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Background: Prostate cancer (PCa) dissemination shows a tendency to develop in the bone, where heme oxygenase 1 (HO-1) plays a critical role in bone remodeling. Previously by LC/ESI-MSMS, we screened for HO-1 interacting proteins and identified annexin 2 (ANXA2). The aim of this study was to analyze the relevance of ANXA2/HO-1 in PCa and bone metastasis. Methods: We assessed ANXA2 levels using a co-culture transwell system of PC3 cells (pre-treated or not with hemin, an HO-1 specific inducer) and the pre-osteoclastic Raw264.7 cell line. Results: Under co-culture conditions, ANXA2 mRNA levels were significantly modulated in both cell lines. Immunofluorescence analysis unveiled a clear ANXA2 reduction in cell membrane immunostaining for Raw264.7 under the same conditions. This effect was supported by the detection of a decrease in Ca2+ concentration in the conditioned medium. HO-1 induction in tumor cells prevented both, the ANXA2 intracellular relocation and the decrease in Ca2+ concentration. Further, secretome analysis revealed urokinase (uPA) as a key player in the communication between osteoclast progenitors and PC3 cells. To assess the clinical significance of ANXA2/HO-1, we performed a bioinformatics analysis and identified that low expression of each gene strongly associated with poor prognosis in PCa regardless of the clinico-pathological parameters assessed. Further, these genes appear to behave in a dependent manner. Conclusions: ANXA2/HO-1 rises as a critical axis in PCa. Fil: Anselmino, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Bizzotto, Juan Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Sanchis, Pablo Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Lage Vickers, Sofia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Ortiz, Emiliano Germán. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Valacco, Maria Pia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Paez, Alejandra. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Labanca, Estefania. University of Texas; Estados Unidos Fil: Meiss, Roberto. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Navone, Nora. University of Texas; Estados Unidos Fil: Cotignola, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Vazquez, Elba Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Gueron, Geraldine. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina

An abrupt increase in metastatic growth as a consequence of the removal of primary tumors suggests that the concomitant resistance (CR) phenomenon might occur in human cancer. CR occurs in murine tumors and ROS-damaged phenylalanine, meta-tyrosine (m-Tyr), was proposed as the serum anti-tumor factor primarily responsible for CR. Herein, we demonstrate for the first time that CR happens in different experimental human solid tumors (prostate, lung anaplastic, and nasopharyngeal carcinoma). Moreover, m-Tyr was detected in the serum of mice bearing prostate cancer (PCa) xenografts. Primary tumor growth was inhibited in animals injected with m-Tyr. Further, the CR phenomenon was reversed when secondary implants were injected into mice with phenylalanine (Phe), a protective amino acid highly present in primary tumors. PCa cells exposed to m-Tyr in vitro showed reduced cell viability, downregulated NFκB/STAT3/Notch axis, and induced autophagy; effects reversed by Phe. Strikingly, m-Tyr administration also impaired both, spontaneous metastasis derived from murine mammary carcinomas (4T1, C7HI, and LMM3) and PCa experimental metastases. Altogether, our findings propose m-Tyr delivery as a novel approach to boost the therapeutic efficacy of the current treatment for metastasis preventing the escape from tumor dormancy. Fil: Gueron, Geraldine. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Anselmino, Nicolás. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Chiarella, Paula. Academia Nacional de Medicina de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Ortiz, Emiliano Germán. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Lage Vickers, Sofia. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Paez, Alejandra. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Giudice, Jimena. University Of North Carolina School Of Medicine; . Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Contin, Mario Daniel. Universidad de Buenos Aires; Argentina Fil: Leonardi, Daiana Beatriz. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Jaworski, Felipe Martín. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Manzano, Veronica Elena. University Of North Carolina School Of Medicine; Fil: Strazza, Ariel Ramiro. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Montagna, Daniela Romina. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Labanca, Estefania. Roswell Park Cancer Institute; Fil: Cotignola, Javier Hernan. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Daccorso, Norma. Universidad de Buenos Aires; Argentina Fil: Woloszynska-Read, Anna. University Of Texas Md Anderson Cancer Center; Fil: Navone, Nora. Roswell Park Cancer Institute; Fil: Meissl, Roberto Jose. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Ruggiero, Raul Alejandro. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Vazquez, Elba Susana. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina

Chagas disease has been described more than 100 years ago and has existed or coexisted with man for millennia.

5-Aminolevulinic acid (ALA) seems to be responsible for the neuropsychiatric manifestations of acute intermittent porphyria (AIP). Our aim was to study the effect of ALA on the different metabolic pathways in the mouse brain to enhance our knowledge about the action of this heme precursor on the central nervous system. Heme metabolism, the cholinergic system, the defense enzyme system, and nitric oxide metabolism were evaluated in the encephalon of CF-1 mice receiving a single (40 mg/kg body mass) or multiple doses of ALA (40 mg/kg, every 48 h for 14 days). We subsequently found ALA accumulation in the encephalon of the mice. ALA also altered the brain cholinergic system. After one dose of ALA, a decrease in superoxide dismutase activity and a reduction in glutathione levels were detected, whereas malondialdehyde levels and catalase activity were increased. Heme oxygenase was also increased as an antioxidant response to protect the encephalon against injury. All nitric oxide synthase isoforms were induced by ALA, these changes were more significant for the inducible isoform in glial cells. In conclusion, ALA affected several metabolic pathways in mouse encephalon. Data indicate that a rapid response to oxidative stress was developed; however, with long-term intoxication, the redox balance was probably restored, thereby minimizing oxidative damage.

Metabolic syndrome (MeS) has been identified as a risk factor for breast cancer. C-terminal binding protein 1 (CtBP1) is a co-repressor of tumor suppressor genes that is activated by low NAD+/NADH ratio. High fat diet (HFD) increases intracellular NADH. We investigated the effect of CtBP1 hyperactivation by HFD intake on mouse breast carcinogenesis. We generated a MeS-like disease in female mice by chronically feeding animals with HFD. MeS increased postnatal mammary gland development and generated prominent duct patterns with markedly increased CtBP1 and Cyclin D1 expression. CtBP1 induced breast cancer cells proliferation. Serum from animals with MeS enriched the stem-like/progenitor cell population from breast cancer cells. CtBP1 increased breast tumor growth in MeS mice modulating multiple genes and miRNA expression implicated in cell proliferation, progenitor cells phenotype, epithelial to mesenchymal transition, mammary development and cell communication in the xenografts. These results define a novel function for CtBP1 in breast carcinogenesis. Fil: de Luca, Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Dalton, Guillermo Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Scalise, Georgina Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Moiola, Cristian Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Porretti, Juliana Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Massillo, Cintia Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Kordon, Edith Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentina Fil: Gardner, Kevin. National Institutes of Health; Estados Unidos Fil: Zalazar, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Flumian, Carolina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Todaro, Laura Beatriz. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Vazquez, Elba Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Meiss, Roberto. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: de Siervi, Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina

Loss of normal development is a hallmark of cancer. Thus, understanding the mechanisms of tissue-specific developmental regulation and the changes that occur during tumorigenesis may provide insights of both diagnostic and therapeutic importance. In breast cancer, several members of the receptor tyrosine kinases (RTK) family that are well known to promote aggressive breast cancers also have roles in normal breast. We found that Ret, a RTK member, is normally expressed in the mouse glands in lactation. We determined that inhibition of Ret activity in vivo does not alter lactation, however impacts in the transition to involution. Involution is the period with high inflammation which returns the lactating mammary gland to a quiescent state after weaning. Involution has been well described as a post-lactation stage that drives cancer progression. Ret is overexpressed in about 40% of human breast tumors. Previously, using a doxycycline-inducible transgenic mouse model (Ret/MTB) we determined that chronic expression of Ret is oncogenic in the mammary epithelium. However, the stage of development at which Ret expression results in increase mammary tumor incidence has not been identified. To address this, we used the Ret/MTB system, to conditionally overexpress Ret during discrete periods of mammary gland development. We found that Ret is required for efficient transition to involution. We determined that the induction of Ret in Ret/MTB females promotes the expression of factors that drives involution, including premature Stat3 activation. RNA-seq data in Ret-overexpressing glands is supporting these findings, which were confirmed by several techniques. In addition, sustained expression of Ret during post-lactation enhances cancer potential showing a significant increase in pre-neoplastic lesions, defective milk recycling and disrupting Stat3 signaling. These results demonstrate that Ret deregulation increases cancer potential in post-lactation and might be considered as a prognostic marker for post-partum breast cancer. Citation Format: Sabrina A. Vallone, Martín García Solá, Robert D. Cardiff, Roberto P. Meiss, Lewis A. Chodosh, Carolina Shere-Levy, Edith C C. Kordon, Nancy E. Hynes, Albana Gattelli. Sustained Ret expression during mammary gland post-lactation induces premature involution and enhances cancer potential [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3685.

R-spondin3 (RSPO3) is a member of a family of secreted proteins that enhance Wnt signaling pathways in diverse processes, including cancer. However, the role of RSPO3 in mammary gland and breast cancer development remains unclear. In this study, we show that RSPO3 is expressed in the basal stem cell-enriched compartment of normal mouse mammary glands but is absent from committed mature luminal cells in which exogenous RSPO3 impairs lactogenic differentiation. RSPO3 knockdown in basal-like mouse mammary tumor cells reduced canonical Wnt signaling, epithelial-to-mesenchymal transition-like features, migration capacity, and tumor formation in vivo. Conversely, RSPO3 overexpression, which was associated with some LGR and RUNX factors, highly correlated with the basal-like subtype among patients with breast cancer. Thus, we identified RSPO3 as a novel key modulator of breast cancer development and a potential target for treatment of basal-like breast cancers., Facultad de Ciencias Médicas, Centro de Investigaciones Inmunológicas Básicas y Aplicadas

Purpose: Conditioning strategies constitute a relatively unexplored and exciting opportunity to shape tumor fate by targeting the tumor microenvironment. In this study, we assessed how hemin, a pharmacologic inducer of heme oxygenase-1 (HO-1), has an impact on prostate cancer development in an in vivo conditioning model. Experimental Design: The stroma of C57BL/6 mice was conditioned by subcutaneous administration of hemin prior to TRAMP-C1 tumor challenge. Complementary in vitro and in vivo assays were performed to evaluate hemin effect on both angiogenesis and the immune response. To gain clinical insight, we used prostate cancer patient-derived samples in our studies to assess the expression of HO-1 and other relevant genes. Results: Conditioning resulted in increased tumor latency and decreased initial growth rate. Histologic analysis of tumors grown in conditioned mice revealed impaired vascularization. Hemin-treated human umbilical vein endothelial cells (HUVEC) exhibited decreased tubulogenesis in vitro only in the presence of TRAMP-C1-conditioned media. Subcutaneous hemin conditioning hindered tumor-associated neovascularization in an in vivo Matrigel plug assay. In addition, hemin boosted CD8+ T-cell proliferation and degranulation in vitro and antigen-specific cytotoxicity in vivo. A significant systemic increase in CD8+ T-cell frequency was observed in preconditioned tumor-bearing mice. Tumors from hemin-conditioned mice showed reduced expression of galectin-1 (Gal-1), key modulator of tumor angiogenesis and immunity, evidencing persistent remodeling of the microenvironment. We also found a subset of prostate cancer patient-derived xenografts and prostate cancer patient samples with mild HO-1 and low Gal-1 expression levels. Conclusions: These results highlight a novel function of a human-used drug as a means of boosting the antitumor response. Fil: Jaworski, Felipe Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina Fil: Gentilini, Lucas Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina Fil: Gueron, Geraldine. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina Fil: Meiss, Roberto P.. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Ortiz, Emiliano Germán. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina Fil: Berguer, Paula Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina Fil: Ahmed, Asif. University of Aston; Reino Unido Fil: Navone, Nora. University of Texas; Estados Unidos Fil: Rabinovich, Gabriel Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina Fil: Compagno, Daniel Georges. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina Fil: Laderach, Diego Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina. Universidad Nacional de Luján. Departamento de Ciencias Básicas; Argentina Fil: Vazquez, Elba Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina

Due to some inconsistencies in the figures provided by the first author that have come to light, and after a thorough investigation we would like to retract our paper: “Low doses of CPS49 and flavopiridol combination as potential treatment for advanced prostate cancer. By: Zalazar F, De Luca P, Gardner K, Figg WD, Meiss R, Spallanzani RG, Vallecorsa P, Elguero B, Cotignola J, Vazquez E, De Siervi A. Curr. Pharm. Biotechnol., 2015, 16(6), 553-63. : Submission of a manuscript to the respective journals implies that all authors have read and agreed to the content of the Copyright Letter or the Terms and Conditions. As such this article represents a severe abuse of the scientific publishing system. Bentham Science Publishers takes a very strong view on this matter and apologizes to the readers of the journal for any inconvenience this may cause.

Hemolytic Uremic Syndrome (HUS) caused by infections with Shiga toxin (Stx)-producing E. coli is a life-threatening complication characterized by acute renal failure, thrombocytopenia and hemolytic anemia. Stx is the main pathogenic factor. Therefore, the mouse model by intravenous administration of a single lethal dose of Stx is often used to explore its pathogenic mechanisms. The aim of this work was to develop an alternative mouse model of Stx type 2 (Stx2) intoxication to evaluate new therapeutic strategies. Fil: Mejias, María Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Fernández Brando, Romina Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Ramos, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Abrey Recalde, Maria Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Zotta, Elsa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; Argentina Fil: Meissl, Roberto Jose. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Palermo, Marina Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina

Concomitant tumor resistance (CR) is a phenomenon in which a tumor-bearing host is resistant to the growth of secondary tumor implants and metastasis. Although previous studies indicated that T-cell-dependent processes mediate CR in hosts bearing immunogenic small tumors, manifestations of CR induced by immunogenic and nonimmunogenic large tumors have been associated with an elusive serum factor. In a recently published study, we identified this factor as meta-tyrosine and ortho-tyrosine, 2 isomers of tyrosine that would not be present in normal proteins. In 3 different murine models of cancer that generate CR, both meta- and orthotyrosine inhibited tumor growth. Additionally, we showed that both isoforms of tyrosine blocked metastasis in a fourth model that does not generate CR but is sensitive to CR induced by other tumors. Mechanistic studies showed that the antitumor effects of the tyrosine isomers were mediated in part by early inhibition of the MAP/ERK pathway and inactivation of STAT3, potentially driving tumor cells into a state of dormancy in G 0-phase. Other mechanisms, putatively involving the activation of an intra-S-phase checkpoint, would also inhibit tumor proliferation by accumulating cells in S-phase. By revealing a molecular basis for the classical phenomenon of CR, our findings may stimulate new generalized approaches to limit the development of metastases that arise after resection of primary tumors or after other stressors that may promote the escape of metastases from dormancy, an issue that is of pivotal importance to oncologists and their patients. ©2012 AACR. Fil: Ruggiero, Raul Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Bruzzo Iraola, Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Chiarella, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Bustuoabad, Oscar David. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Meiss, Roberto P.. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Pasqualini, Christiane D.. Academia Nacional de Medicina de Buenos Aires; Argentina

Concomitant tumor resistance (CR) is a phenomenon originally described in 1906 in which a tumor-bearing host is resistant to the growth of secondary tumor implants and metastasis. Although recent studies have indicated that T-cell-dependent processes mediate CR in hosts bearing immunogenic small tumors, manifestations of CR induced by immunogenic and nonimmunogenic large tumors have been associated with an elusive serum factor. In this study, we identify this serum factor as tyrosine in its meta and ortho isoforms. In three different murine models of cancer that generate CR, both meta-tyrosine and ortho-tyrosine inhibited tumor growth. In addition, we showed that both isoforms of tyrosine blocked metastasis in a fourth model that does not generate CR but is sensitive to CR induced by other tumors. Mechanistic studies showed that the antitumor effects of the tyrosine isoforms were mediated, in part, by early inhibition of mitogen-activated protein/extracellular signal-regulated kinase pathway and inactivation of STAT3, potentially driving tumor cells into a state of dormancy. By revealing a molecular basis for the classical phenomenon of CR, our findings may stimulate new generalized approaches to limit the development of metastases that arise after resection of primary tumors, an issue of pivotal importance to oncologists and their patients. ©2011 AACR. Fil: Ruggiero, Raul Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Bruzzo Iraola, Juan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Chiarella, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Di Gianni, Pedro. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Isturiz, Martín Amadeo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Linskens, Susana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina Fil: Speziale, Norma. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina Fil: Meiss, Roberto P.. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Bustuoabad, Oscar David. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Pasqualini, Christiane D.. Academia Nacional de Medicina de Buenos Aires; Argentina

An abrupt increase in metastatic growth as a consequence of the removal of primary tumors suggests that the concomitant resistance (CR) phenomenon might occur in human cancer. CR occurs in murine tumors and ROS-damaged phenylalanine, meta-tyrosine (m-Tyr), was proposed as the serum anti-tumor factor primarily responsible for CR. Herein, we demonstrate for the first time that CR happens in different experimental human solid tumors (prostate, lung anaplastic, and nasopharyngeal carcinoma). Moreover, m-Tyr was detected in the serum of mice bearing prostate cancer (PCa) xenografts. Primary tumor growth was inhibited in animals injected with m-Tyr. Further, the CR phenomenon was reversed when secondary implants were injected into mice with phenylalanine (Phe), a protective amino acid highly present in primary tumors. PCa cells exposed to m-Tyr in vitro showed reduced cell viability, downregulated NFκB/STAT3/Notch axis, and induced autophagy; effects reversed by Phe. Strikingly, m-Tyr administration also impaired both, spontaneous metastasis derived from murine mammary carcinomas (4T1, C7HI, and LMM3) and PCa experimental metastases. Altogether, our findings propose m-Tyr delivery as a novel approach to boost the therapeutic efficacy of the current treatment for metastasis preventing the escape from tumor dormancy. Citation Format: Nicolás Anselmino, Paula Chiarella, Emiliano G. Ortiz, Daiana B. Leonardi, Felipe M. Jaworski, Sofia Lage Vikers, Jimena Giudice, Anna Woloszynska-Read, Roberto P. Meiss, Raul Rugiero, Geraldine Gueron, Elba S. Vazquez. Game-changing restraint of Ros-damaged phenylalanine, upon tumor metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4180.

Background: The phenomenon of hormesis is characterized by a biphasic dose-response, exhibiting opposite effects in the low- and high-dose zones. In this study, we explored the possibility that the hormesis concept may describe the interactions between two tumors implanted in a single mouse, such that the resulting tumors are of different sizes. Materials and methods: We used two murine tumors of spontaneous origin and undetectable immunogenicity growing in BALB/c mice. A measure of cell proliferation was obtained by immunostaining for Ki-67 protein and by using the [3H] thymidine uptake assay. For serum fractionation, we utilized dialysis and chromatography on Sephadex G-15. Results: The larger primary tumor induced inhibitory or stimulatory effects on the growth of the smaller secondary one, depending on the ratio between the mass of the larger tumor relative to that of the smaller one, with high ratios rendering inhibition and low ratios inducing stimulation of the secondary tumor. Conclusion: Since metastases can be considered as natural secondary tumor implants in a tumor-bearing host and that they constitute the main problem in cancer pathology, the use of the concept of hormesis to describe those biphasic effects might have significant clinical implications. In effect, if the tumor-bearing host were placed in the inhibitory window, tumor extirpation could enhance the growth of distant metastases and, reciprocally, if placed in the stimulatory window, tumor extirpation would result not only in a reduction or elimination of primary tumor load but also in a slower growth or inhibition of metastases. © 2010 Springer-Verlag. Fil: Bruzzo Iraola, Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Chiarella, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Meissl, Roberto Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Ruggiero, Raul Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina

Summary Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 infections are considered a public health problem in both developed and developing countries because of their increasing incidence and the severity of clinical presentation. Approximately 10% of infected patients develop complications such as haemolytic uraemic syndrome (HUS) characterized by acute renal failure, thrombocytopenia and haemolytic anaemia. The precise sequence of events leading to HUS is still understood incompletely. Because of the lack of a reproducible small animal model for EHEC infections, in vivo studies examining EHEC–host early interactions are limited and insufficient. The aim of this study was to characterize the weaned BALB/c mouse as a model of E. coli O157:H7 infection. In this paper we report that human Shiga toxin 2 (Stx2)-producing EHEC strains can adhere to the intestinal epithelium of weaned BALB/c mice, and produce local damage which leads to systemic disease and death in a percentage of infected mice. The lethality of the EHEC strain is closely age-dependent, and is related to the bacterial ability to colonize intestine and to produce Stx2. It can be concluded that the weaned BALB/c mouse can be used as a small animal model to study host early responses, and the role of bacterial pathogenic factors in the induction of systemic disease, thus providing a useful tool for the evaluation of therapeutic or vaccine approaches.

Background : Nitric oxide (NO) is an endogenous vasodilator and platelet inhibitor. An enhanced NO production has been detected in patients with hemolytic uremic syndrome (HUS), although its implication in HUS pathogenesis has not been clarified. Methods : A mouse model of Shiga toxin 2 (Stx2)-induced HUS was used to study the role of NO in the development of the disease. Modulation of L-arginine-NO pathway was achieved by oral administration of NO synthase (NOS) substrate or inhibitors, and renal damage, mortality and platelet activity were evaluated. The involvement of platelets was studied by means of a specific anti-platelet antibody. Results : Inhibition of NO generation by the NOS inhibitor L-NAME enhanced Stx2-mediated renal damage and lethality; this effect was prevented by the addition of L-arginine. The worsening effect of L-NAME involved enhanced Stx2-mediated platelet activation, and it was completely prevented by platelet depletion. Conclusions : NO exerts a protective role in the early pathogenesis of HUS, and its inhibition potentiates renal damage and mortality through a mechanism involving enhanced platelet activation. Fil: Dran, Graciela Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Fernández, Gabriela Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Rubel, Carolina J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Bermejo, Emilse. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Gómez, Sonia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Meiss, Roberto Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Isturiz, Martín Amadeo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Palermo, Marina Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina

We studied the effect of deferoxamine (DFX), an iron chelator, which can also act as a free radical scavenger, in an experimental murine model of sepsis. In vivo studies demonstrated that pretreatment of mice with DFX reduces tumor necrosis factor alpha (TNF-alpha) serum levels and increases the rate of survival of mice inoculated with lethal doses of lipopolysaccharide (LPS) or Escherichia coli O111:B4. By using the iron chelated form of DFX (ferrioxamine) the same results were obtained, suggesting that in this model, DFX could act as a free radical scavenger. On the other hand, DFX prevents mortality induced either by LPS or murine recombinant TNF-alpha in D(+)-galactosamine (GalN)-sensitized mice. These protective actions of DFX correlate with an attenuated tissue damage observed in lungs, livers and kidneys of LPS-treated animals and GalN-sensitized mice inoculated with TNF-alpha.

Prostate cancer (PCa) is a leading cause of death among males. It is currently estimated that inflammatory responses are linked to 15-20% of all deaths from cancer worldwide. PCa is dominated by complications arising from metastasis to the bone where the tumor cells interact with the bone microenvironment impairing the balance between bone formation and degradation. However, the molecular nature of this interaction is not completely understood. Heme oxygenase-1 (HO-1) counteracts oxidative damage and inflammation. Previous studies from our laboratory showed that HO-1 is implicated in PCa, demonstrating that endogenous HO-1 inhibits bone derived-prostate cancer cells proliferation, invasion and migration and decreases tumor growth and angiogenesis in vivo. The aim of this work was to analyze the impact of HO-1 modulated PCa cells on osteoblasts proliferation in vitro and on bone remodeling in vivo. Using a co-culture system of PC3 cells with primary mice osteoblasts (PMOs), we demonstrated that HO-1 pharmacological induction (hemin treatment) abrogated the diminution of PMOs proliferation induced by PCa cells and decreased the expression of osteoclast-modulating factors in osteoblasts. No changes were detected in the expression of genes involved in osteoblasts differentiation. However, co-culture of hemin pre-treated PC3 cells (PC3 Hem) with PMOs provoked an oxidative status and activated FoxO signaling in osteoblasts. The percentage of active osteoblasts positive for HO-1 increased in calvarias explants co-cultured with PC3 Hem cells. Nuclear HO-1 expression was detected in tumors generated by in vivo bone injection of HO-1 stable transfected PC3 (PC3HO-1) cells in the femur of SCID mice. These results suggest that HO-1 has the potential to modify the bone microenvironment impacting on PCa bone metastasis. Fil: Ferrando, María Mercedes Catalina. DTO.DE QUIMICA BIOLOGICA; Fil: Wan, Xinahi. Fil: Meissl, Roberto Jose. Academia Nacional de Medicina de Buenos Aires; Fil: Yang, Yung. Fil: de Siervi, Adriana. Consejo Nacional de Invest.cientif.y Tecnicas. Instituto de Biologia y Medicina Experimental (i); Fil: Navone, Nora. Fil: Vazquez, Elba Susana. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Quimica Biologica

Clinical and experimental evidence suggest that primary tumors may exert a controlling action on its metastases. The phenomenon, by which a tumor-bearing host is resistant to the growth of secondary tumor implants and metastasis, is known as concomitant tumor resistance (CR). We have previously showed in murine T-lymphoma (LB) tumors, that meta-tyrosine (m-Tyr) an isomer of tyrosine not present in normal proteins, is the main serum anti-tumoral factor responsible for CR. In this work, we assess for the first time the CR phenomenon in human prostate cancer (PCa). Athymic nude mice were inoculated with PC3 cells (primary implant) and after 14 days the animals received a second inoculation (secondary implant). Strikingly, the growth of the secondary implant was significantly reduced after 27 days, in animals carrying the primary xenograft. When phenylalanine (Phe), a protective amino acid highly present in primary tumors, and precursor of p-tyrosine, was periodically inoculated at the site of a secondary tumor implant (otherwise inhibited by CR), this secondary implant grew similarly to controls. On the contrary, when m-Tyr was inoculated at the site of a primary tumor implant or systemically, this implant did not grow. Tumor inhibition was associated with low expression of Ki-67 and STAT3. In vitro analyses demonstrate the higher inhibitory activity of the serum from tumor-bearing mice on PC3 cell proliferation, compared to serum from control animals. m-Tyr could account for most of the growth-inhibitory activity present in the serum. Furthermore, we observed an increase in the frequency of Gr1+ CD11b+ MDSCs in bone marrow, spleen and lymph nodes from tumor-bearing mice compared to control mice. This expansion correlated with a significantly higher production of reactive oxygen species and enhanced suppressor function upon CD8+ T cell proliferation. Further, in vitro studies also showed that exposure of PC3 cells to m-Tyr inhibited cell growth, induced G0/G1 cell cycle arrest, altered the expression levels of survivin, Ki67 and Hes1; impaired the NFκB/STAT3 pathway and induced autophagy; effects reversed by Phe treatment. Strikingly, m-Tyr periodic intravenous administration provoked a dramatic reduction of experimental lung metastases generated in mice bearing PC3 human tumors. Altogether, we demonstrate for the first time that RC occurs in experimental human solid tumors, that this effect is mediated by m-Tyr, a non-cytotoxic metabolite with high potential clinical implications for metastatic PCa. Citation Format: Geraldine Gueron, Nicolás Anselmino, Paula Chiarella, Emiliano Ortiz, Alejandra Paez, Jimena Giudice, Federico Schuster, Daiana Leonardi, Felipe Jaworski, Estefania Labanca, Verónica Manzano, Javier Cotignola, Roberto Meiss, Norma D′Accorso, Nora Navone, Raul Ruggiero, Elba Vazquez. Clinical implications for m-tyrosine, an isomer of p-tyrosine, for the treatment of aggressive prostate tumors. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4717.

Concomitant tumor resistance (CR) is a phenomenon in which a tumor-bearing host is resistant to the growth of secondary tumor implants. This phenomenon has been described in human and animal systems and it can be generated by both immunogenic and non-immunogenic tumors. The relevance of CR to the mechanisms of metastases control has been highlighted by numerous observations showing that the removal of human and murine tumors may be followed by an abrupt increase in metastatic growth, suggesting that a primary tumor may exert a controlling action on its metastases which could be considered as secondary tumor implants developed spontaneously during the primary tumor growth. A more profound understanding of the different mechanisms claimed to be associated with the phenomenon of CR could contribute to develop new and more harmless means to manage malignant diseases, especially by limiting the development of metastases that arise after resection of primary tumors or after other stressors that may promote the escape of metastases from dormancy. Fil: Chiarella, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Bruzzo Iraola, Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Meiss, Roberto P.. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Ruggiero, Raul Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina

Prostate cancer (PCa) is the second leading cause of cancer-associated death in men. Once a tumor is established it may attain further characteristics via mutations or hypoxia, which stimulate new blood vessels. Angiogenesis is a hallmark in the pathogenesis of cancer and inflammatory diseases that may predispose to cancer. Heme oxygenase-1 (HO-1) counteracts oxidative and inflammatory damage and was previously reported to play a key role in prostate carcinogenesis. To gain insight into the anti-tumoral properties of HO-1, we investigated its capability to modulate PCa associated-angiogenesis. In the present study, we identified in PC3 cells a set of inflammatory and pro-angiogenic genes down-regulated in response to HO-1 overexpression, in particular VEGFA, VEGFC, HIF1α and α5β1 integrin. Our results indicated that HO-1 counteracts oxidative imbalance reducing ROS levels. An in vivo angiogenic assay showed that intradermal inoculation of PC3 cells stable transfected with HO-1 (PC3HO-1) generated tumours less vascularised than controls, with decreased microvessel density and reduced CD34 and MMP9 positive staining. Interestingly, longer term grown PC3HO-1 xenografts displayed reduced neovascularization with the subsequent down-regulation of VEGFR2 expression. Additionally, HO-1 repressed nuclear factor κB (NF-κB)-mediated transcription from an NF-κB responsive luciferase reporter construct, which strongly suggests that HO-1 may regulate angiogenesis through this pathway. Taken together, these data supports a key role of HO-1 as a modulator of the angiogenic switch in prostate carcinogenesis ascertaining it as a logical target for intervention therapy. Fil: Ferrando M. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Gueron geraldine. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Elguero, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Giudice J. Baylor College Of Medicine; Estados Unidos Fil: Salles A. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Leskow FC. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Jares-Erijman EA. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina Fil: Colombo L. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina Fil: Meissl, Roberto Jose. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Navone, Nora. M. D. Anderson Cancer Center; Estados Unidos Fil: de Siervi, Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Vazquez Elba. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina

Severe sepsis is associated with early release of inflammatory mediators that contribute to the morbidity and mortality observed during the first stages of this syndrome. Although sepsis is a deadly, acute disease, high mortality rates have been observed in patients displaying evidence of sepsis-induced immune deactivation. Although the contribution of experimental models to the knowledge of pathophysiological and therapeutic aspects of human sepsis is undeniable, most of the current studies using animal models have focused on the acute, proinflammatory phase. We developed a murine model that reproduces the early acute phases but also the long-term consequences of human sepsis. We induced polymicrobial acute peritonitis (AP) by establishing a surgical connection between the cecum and the peritoneum, allowing the exit of intestinal bacteria. Using this model, we observed an acute phase with high mortality, leukopenia, increased interleukin-6 levels, bacteremia, and neutrophil activation. A peak of leukocytosis on day 9 or 10 revealed the persistence of the infection within the lung and liver, with inflammatory hepatic damage being shown by histological examination. Long-term (20 days) derangements in both innate and adaptive immune responses were found, as demonstrated by impaired systemic tumor necrosis factor alpha production in response to an inflammatory stimulus; a decreased primary humoral immune response and T cell proliferation, associated with an increased number of myeloid suppressor cells (Gr-1 CD11b ) in the spleen; and a low clearance capacity. This model provides a good approach to attempt novel therapeutic interventions directed to augmenting host immunity during late sepsis. Severe sepsis is associated with early release of inflammatory mediators that contribute to the morbidity and mortality observed during the first stages of this syndrome. Although sepsis is a deadly, acute disease, high mortality rates have been observed in patients displaying evidence of sepsis-induced immune deactivation. Although the contribution of experimental models to the knowledge of pathophysiological and therapeutic aspects of human sepsis is undeniable, most of the current studies using animal models have focused on the acute, proinflammatory phase. We developed a murine model that reproduces the early acute phases but also the long-term consequences of human sepsis. We induced polymicrobial acute peritonitis (AP) by establishing a surgical connection between the cecum and the peritoneum, allowing the exit of intestinal bacteria. Using this model, we observed an acute phase with high mortality, leukopenia, increased interleukin-6 levels, bacteremia, and neutrophil activation. A peak of leukocytosis on day 9 or 10 revealed the persistence of the infection within the lung and liver, with inflammatory hepatic damage being shown by histological examination. Long-term (20 days) derangements in both innate and adaptive immune responses were found, as demonstrated by impaired systemic tumor necrosis factor alpha production in response to an inflammatory stimulus; a decreased primary humoral immune response and T cell proliferation, associated with an increased number of myeloid suppressor cells (Gr-1 CD11b ) in the spleen; and a low clearance capacity. This model provides a good approach to attempt novel therapeutic interventions directed to augmenting host immunity during late sepsis.

The role of oxidative stress in prostate cancer has been increasingly recognised. Acute and chronic inflammations generate reactive oxygen species that result in damage to cellular structures. Haeme oxygenase-1 (HO-1) has cytoprotective effects against oxidative damage. We hypothesise that modulation of HO-1 expression may be involved in the process of prostate carcinogenesis and prostate cancer progression. We thus studied HO-1 expression and localisation in 85 samples of organ-confined primary prostate cancer obtained via radical prostatectomy (Gleason grades 4-9) and in 39 specimens of benign prostatic hyperplasia (BPH). We assessed HO-1 expression by immunohistochemical staining. No significant difference was observed in the cytoplasmic positive reactivity among tumours (84%), non-neoplastic surrounding parenchyma (89%), or BPH samples (87%) (P=0.53). Haeme oxygenase-1 immunostaining was detected in the nuclei of prostate cancer cells in 55 of 85 (65%) patients but less often in non-neoplastic surrounding parenchyma (30 of 85, 35%) or in BPH (9 of 39, 23%) (P

Concomitant tumor resistance (CR) is the phenomenon according to which a tumor-bearing host inhibits the growth of secondary tumor implants. Ehrlich first described it in 1906, but this phenomenon remained forgotten for about 60 years. After its renascence, some groups have demonstrated that both immunogenic and non-immunogenic tumors can induce CR in different animal models. Metastases could be considered as secondary tumor implants developed spontaneously during the primary tumor growth, thus CR could be relevant for cancer progression. Clinical and experimental evidence suggest that the removal of human and murine tumors might be followed by an abrupt increase in metastatic growth, hence the primary tumor could exert a controlling action on its metastases. In previous papers we demonstrated that, in mice, two temporally separate peaks of CR can be detected during murine T-lymphoma (LB) primary tumor growth. The second peak of CR is mediated by most large-sized immunogenic and non-immunogenic tumors and is associated with the anti-tumor and anti-metastatic serum factor meta-tyrosine (m-tyr), an isomer of tyrosine not present in normal proteins. Based on this background, in this work we assessed whether CR was also occurring in human tumor experimental models. Athymic nude mice were inoculated s.c. in the right flank, with the human prostate cancer cell line PC3 (1 × 106, primary implant). After 14 days the animals received a second inoculation of PC3 cells in the left flank (1 × 106, secondary implant). The control group only received the secondary implant. The growth of the secondary implant was significantly reduced (92%; P Citation Format: Geraldine Gueron, Nicolás Anselmino, Damian Manchuca, Emiliano G. Ortiz, Maria Noelia Carabelos, Federico Schuster, Paula Chiarella, Alejandra Paez, Felipe M. Jaworski, Javier Cotignola, Roberto Meiss, Raul Ruggiero, Elba S. Vazquez. A second round for concomitant resistance in human cancer: A restraint upon metastasis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5199. doi:10.1158/1538-7445.AM2015-5199

Breast cancer is still one of the most important public health problems in the entire world. Obesity and metabolic syndrome (MS) increases the incidence and aggressiveness of breast cancer. C-Terminal Binding Protein (CtBP1) is a transcriptional corepressor of tumor suppressor genes and is considered a molecular sensor of cell metabolic state due to is activated in high energy conditions (high NADH). In this work we studied the effects of the activation of CtBP1 pathway by metabolic syndrome on breast tumor development and progression. We generated a murine model of MS by chronic high fat diet (HFD) administration. By histological and whole mount methods, we found that breast tissue of animals receiving HFD presented higher levels of immature adipose tissue and an increased glandular area with more generation of lateral branches and terminal end buds of mammary ducts. Breast tissue of HFD animals also showed higher expression of the proliferation markers (cyclin D1) and epithelial markers (E-cadherin). Interestingly, HFD induced CtBP1 expression in the mammary ducts. Furthermore, the number and size of mamospheres generated with LM38-LP breast cancer cells were significantly increased when cells were incubated with serum from HFD fed mice compared to the serum of animals under control diet (CD). In addition, to investigate CtBP1 role in tumor progression we performed xenografts in nude mice fed with CD or HFD by subcutaneous injecton of breast tumor cells MDA MB 231 with depleted CtBP1 expression (shRNA CtBP1) or control cells (shRNA scramble). We found that CtBP1 depletion dramatically decreased tumor growth and KI67 expression relative to control tumors. Furthermore, xenografts developed in HFD fed mice were less differentiated compared to CD. Finally, CtBP1 diminished expression tumors showed lower mesenchymal markers expression, progenitor cells markers and markers involved in mammary development. Our studies demonstrated for the first time that gene transcription regulation by CtBP1 provides an important molecular link among MS, CtBP1 function and tumor growth. Hence, these results suggest an association to understand metabolism and breast cancer. Citation Format: Paola De Luca, Nicolás Dalton, Cristian Pablo Moiola, Carolina Flumian, Georgina Scalise, Juliana Porretti, Cintia Massillo, Edith Kordon, Laura Todaro, Elba Vazquez, Roberto Meiss, Adriana De Siervi. CtBP1 is the molecular link that associates breast cancer and metabolic syndrome. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1160. doi:10.1158/1538-7445.AM2015-1160

The spontaneous non-obese diabetic (NOD) mouse model of Sjögren's syndrome provides a valuable tool to study the onset and progression of both the autoimmune response and secretory dysfunction. Our purpose was to analyse the temporal decline of salivary secretion in NOD mice in relation to the autoimmune response and alterations in various signalling pathways involved in saliva secretion within each salivary gland. A progressive loss of nitric oxide synthase activity in submandibular and parotid glands started at 12 weeks of age and paralleled the decline in salivary secretion. This defect was associated with a lower response to vasoactive intestinal peptide in salivary flow rate, cAMP and nitric oxide/cGMP production. No signs of mononuclear infiltrates or local cytokine production were detectable in salivary glands in the time period studied (10-16 weeks of age). Our data support a disease model for sialadenitis in NOD mice in which the early stages are characterized by defective neurotransmitter-mediated signalling in major salivary glands that precedes the autoimmune response. Fil: Rosignoli, F.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad Complutense de Madrid; España Fil: Roca, Valeria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Meiss, R.. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Leceta, J.. Universidad Complutense de Madrid; España Fil: Gomariz, R.P.. Universidad Complutense de Madrid; España Fil: Perez Leiros, Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina

A small primary or secondary tumor load can occasionally induce more deleterious effects than a histologically identical larger one. In the four murine models studied herein this enhanced tumor aggressiveness could not be attributed to NRAS mutations or other hereditary changes, differential vascularization of live tumor tissues, or necrosis content. Instead, the main tumor feature associated with a more aggressive behavior was the presence of a high number of vessels, sometimes filled with inflammatory cells, inside a tumor area, which we have identified and designated as the transition zone between the live and the necrotic zones. Our experiments suggest that during tumor growth, different cachectic factors are produced within the transition and necrotic zones by dying tumor cells and by tumor infiltrating macrophages only reaching the general circulation through the vessels present in the transition zone. Therefore, a small tumor displaying high vascularization of its transition area could be harmful to its host, while, in contrast, a large tumor could behave as a relatively benign one if its transition zone exhibited little or no vascularization, and in consequence its cachectic factors remained "trapped." Similar histological images to those observed in mice were seen in a significant percentage of human cancer biopsies, raising the possibility that such images might have a prognostic value.

In this paper we demonstrate, using the C7-2-HI metastatic transplantable ductal mammary tumor, that endocrine therapy can induce complete regression of spontaneous lymph node and lung metastases in a mouse model of breast cancer progression. This tumor expresses high levels of estrogen and progesterone receptors and shows a high incidence of early axillary lymph nodes and lung metastases; using this model we had previously shown complete tumor regression of subcutaneous implants. Interestingly, although the metastases showed a more differentiated histology as compared with the primary growth, they underwent complete regression when treated with estrogens or antiprogestins. This phenomenon was associated with sustained cytostasis and apoptosis accompanied by increases in p21 and p27 expression and early tissue remodeling. These results highlight the essential role of PR in regulating cell proliferation in this model as well as its possible use as therapeutic target. Fil: Vanzulli, Silvia. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Soldati, Rocío. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Meiss, Roberto. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Colombo, Lucas Luis. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología ; Argentina Fil: Molinolo, Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Public Health Service. National Institute Of Health; Estados Unidos Fil: Lanari, Claudia Lee Malvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina

Clinical and epidemiological data suggest that obesity is associated with more aggressive forms of prostate cancer (PCa), poor prognosis and increased mortality. In addition, high calorie intake decreases intracellular NAD+/NADH ratio. C-terminal Binding Protein 1 (CtBP1) is a transcription repressor of several important tumor suppressor genes and is activated by NADH binding. The aim of this work was to assess the effect of a high fat diet (HFD) and CtBP1 expression modulation over PCa tumor development in a murine xenograft model. We developed a metabolic syndrome-like disease in vivo model. Male nude mice fed with HFD or control diet (CD) for 16 weeks showed hypercholesterolemia, low testosterone serum levels, liver steatosis and glomeruli enlargement with edema at the kidney ephitelium collecting duct. In addition, at week 12 of diet, prostate tumor PC3 cells stable transfected with shCtBP1 or control (pGIPZ) plasmids were s.c. inoculated into randomly divided mice groups. No significant differences were observed in tumor growth on CD fed mice; however, we found that only 60 % of HFD fed mice inoculated with CtBP1 depleted cells developed a tumor; even more these tumors were significantly smaller than those generated by PC3.pGIPZ control xenografts. Furthermore, CtBP1 depletion in xenograft tumors was validated by IHQ and RT-qPCR. Genome-wide expression profiles (HUGENE ST1.0 Affymetrix) from PC3.shCtBP1 versus PC3.pGIPZ HFD fed mice tumors showed 823 genes differentially expressed (1.5 fold change and p < 0.05). By biological process GO classification, we found that most of these genes correspond to cell adhesion, metabolic process, apoptosis and cell cycle among others GO terms. In addition, we performed Gene Set Enrichment Analyses (GSEA) from our expression datasets and contrasted our results using MSigDB (C2 and C5 gene sets collection). We identified gene sets associated with metabolic and cellular processes. Interestingly, E-cadherin (CDH1) and aromatase (CYP19A1) expression were up-regulated in CtBP1 depleted tumors, and we validated this evidence by RT-qPCR. Our results suggested that metabolic syndrome-like diseases and CtBP1 expression might cooperate to PCa tumor development. Hence, CtBP1 expression might be considered for PCa management and therapy in the subset of patient with metabolic syndromes. Citation Format: Cristian P. Moiola, Paola De Luca, Florencia Zalazar, Santiago Rodriguez Segui, Javier Cotignola, Roberto Meiss, Elba Vazquez, Nicolas Dalton, Estefania Labanca, Kevin Gardner, Adriana De Siervi. CtBP1 is implicated in prostate tumor development in a metabolic syndrome-like disease in vivo model. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 247. doi:10.1158/1538-7445.AM2014-247

Mutations in exons 4-8 of the p53 gene by the PCR-SSCP analysis in preneoplastic and neoplastic lesions of the colon (n=11) and esophagus (n=18) were screened. p53 overexpression by immunohistochemistry in 11 colonic lesions and 13 microsatellites, in all the patients (n=29), were also studied. A positive result concordancy between the three techniques was found in 1 adenoma and 2 adenocarcinomas of the colon, each with loss of heterozygocity of microsatellites. Metaplastic lesions of esophagus showed biallelic mutations and low frequency of microsatellite alterations. The relationship between genetic alterations in p53, microsatellites and type of colon and esophageal lesions is discussed.

We show here, for the first time, in two very different murine tumors, a mammary one (ectoderm) and a lung one (endoderm), that: tumors have day/night differences of spontaneous apoptosis additional to the well-known circadian rhythm of mitosis. The times of maximal and minimal mitosis and apoptosis changed for a tumor cell line when growing in different organs (as metastasis) or anatomical sites. Both tumor lines, have identical circadian curves when growing in a specific organ or anatomical site. The peaks of apoptosis match with the valleys of mitosis and vice versa. Fil: Colombo, Lucas Luis. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Mazzoni, Esteban O.. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología; Argentina Fil: Meiss, Roberto Pablo. Academia Nacional de Medicina de Buenos Aires; Argentina

Concomitant resistance (CR) is the phenomenon according to which a tumor-bearing host inhibits the growth of a secondary implant of the same tumor at a distant site. Confirming and extending previous results of our laboratory, histological studies have revealed that two temporally separate peaks of CR can be detected throughout tumor evolution. The first peak induced by immunogenic small tumors, in euthymic but not in nude mice, is associated with extensive necrosis of the secondary tumor implant and a profuse infiltration of polymorphonuclear granulocytes and mononuclear cells resulting in its final destruction; these features correspond to a typical immunological rejection. The second peak of CR induced by both immunogenic and non-immunogenic large tumors, in euthymic as well as in nude mice, is characterized by a dormant tumor stage with scarce or null mononuclear infiltration, associated with a significant reduction of tumor mitotic index and of the number of PCNA+ cells along with an increase in apoptosis and an arrest in S phase. In previous reports we suggested that a 1000 D serum fraction from mice bearing large tumors could be responsible for the induction of this dormant tumor stage. In this study tumor cells incubated in vitro with that serum factor mimicked the inhibition and cellular alterations observed in vivo in the secondary tumor inhibited by the second peak of CR. Moreover, the passive transfer of this factor by the intra-peritoneal (i.p.) route induced an in vivo inhibition of an i.p. tumor reproducing the image characteristic of the second peak of CR. This represents a direct proof that this serum factor can restrain tumor growth in vivo and that it is, most probably, the effector of the second peak of CR.

One of the most promising substances used in photodynamic therapy (PDT) is 5-aminolevulinic acid (ALA), which induces endogenous synthesis and accumulation of porphyrins in malignant cells. In this paper we have shown that both topical and intratumoral administration of ALA in a subcutaneously implanted mammary carcinoma produced a significant synthesis of porphyrins and subsequent sensitization to laser light. Porphyrin accumulation was greater when ALA was administered intratumorally and tumour/normal skin porphyrin concentration ratios were higher compared with topical application. Irradiation was optimal between 2 and 3 h after topical application of 50 mg of a 20% ALA cream and 2–4 h after intratumoral administration of 30 mg ALA/cm3. The pattern of tumour response evaluated as the delay of tumour growth was similar following either route of drug administration. Applications of PDT were performed once, twice or three times in the study. The response to successive applications was constant for the same tumour, indicating that no resistance was acquired. Microscopic analysis showed both induction of foci of necrosis and haemorrhage, morphological features of apoptotic cells and total absence of cellular immune response. This paper reports on PDT with topical ALA in a subcutaneous carcinoma leading to tumour growth delay. These findings may have great relevance in the treatment of cutaneous metastasis of mammary carcinomas.

Murine lung metatases growing undisturbed by the primary tumor were significantly inhibited by the concomitant resistance induced by a secondary subcutaneous implant of two unrelated tumors. Such inhibition was T-independent since it was also observed in nude mice; its full expression was dependent on the presence of the secondary tumor implant and it was exerted on both macroscopic and microscopic established metastases and not on the process of tumor cell dissemination from the primary tumor. Direct and indirect mechanisms seemed to be involved, the former affecting the metastatic cells per se by causing a decrease in proliferation and an increase in apoptosis while the latter affected neo-vascularization. These antitumor and antiangiogenic effects could be attributed to a serum factor induced by the unrelated tumors generating concomitant resistance. This factor proved to be heat, acid and alkaline resistant and dialysable; it was recovered in an HPLC column with maximum absorption at 215 and 266 nm; it was anionic at neutral pH, exhibiting free carboxil groups and one or more molecules of tyrosine, with a molecular weight between 870 and 1300 Dalton. Intravenous administration of this factor significantly inhibited lung metastases, decreasing mitosis and increasing apoptosis similar to that observed in the presence of the unrelated tumors.

Prostate Cancer (PCa) is one of the most common invasive tumors in men. Epidemiological studies indicate that diet and overweight are important factors implicated in prostate carcinogenesis. Obesity is associated with PCa aggressiveness, poorer prognosis and increased mortality. Breast cancer susceptibility gene 1 (BRCA1) interacts with several transcriptional regulators to modulate the androgen receptor (AR) signaling in PCa cell lines. Germline mutations in this gene increase breast cancer risk and are associated with high grade PCa. Previously, it had been reported that C-terminal Binding Protein 1 (CtBP1) acts as a switch to control BRCA1 transcription in response to the metabolic status of the cells. The release of CtBP1 from BRCA1 promoter through estrogen induction and high NAD+/NADH ratio (similar to high caloric intake) increases BRCA1 transcription in breast cancer cells. The aim of this work was to assess the effect of androgens and/or high fat diet over the BRCA1/CtBP1 axis and PCa tumor growth. We found that BRCA1 and CtBP1 proteins associate to BRCA1 proximal promoter region in PC3 cells and suppress BRCA1 transcription. Testosterone stimulation released these factors from BRCA1 promoter increasing its transcription. To assess whether this activation is mediated by testosterone or the estrogen, synthesized from testosterone by the aromatase (CYP19A1), we investigated this mechanism in the presence of letrozol (LTZ), an aromatase inhibitor. We found that LTZ abolished BRCA1 induction by testosterone, suggesting that BRCA1 activation is mediated by estrogen in these cells. Furthermore, we generated PC3 cell lines transfected with pcDNA3-CtBP1 (PC3-CtBP1) or shRNA-CtBP1 (PC3-shCtBP1) plasmids, to overexpress or knock down CtBP1 expression, respectively. CtBP1 induction decreased BRCA1 expression in these cells and this effect was reverted by CtBP1 depletion. In addition, PC3-CtBP1 cells showed increased clonogenic capacity and proliferation compared to PC3-shCtBP1 cells. Moreover, we developed an in vivo model to investigate the effect of high caloric diet on PCa growth after CtBP1 modulated-expression. High fat or control diet fed male nude mice were inoculated with PC3-CtBP1 and PC3-shCtBP1 stable cells. We found that CtBP1 depleted cells growing as xenografts in high fat diet fed mice dramatically decreased prostate tumor growth. Molecular analysis of tumors by RT-qPCR showed that CtBP1 depletion correlated with high BRCA1 expression. In addition, serum from high fat fed mice significantly induced PC3-CtBP1 cell proliferation in vitro. These results strongly suggest that the potential oncogenic role of CtBP1 is dependent on the caloric diet intake. Hence, BRCA1 regulation by CtBP1 provides an important molecular link between caloric intake and tumor suppressor expression. Citation Format: Cristian P. Moiola, Paola De Luca, Florencia Zalazar, Javier Cotignola, Estefania Labanca, Roberto Meiss, Elba S. Vazquez, Kevin Gardner, Adriana De Siervi. Molecular link that associates high fat diet and prostate tumor growth. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3697. doi:10.1158/1538-7445.AM2013-3697

Prostate cancer (PCa) still ranks as the second most commonly diagnosed cancer and metastatic castration-resistant prostate cancer (CRPC) is a leading cause of cancer death in men around the world. The common treatment for patients with CRPC is chemotherapy based on docetaxel. While there are currently seven agents approved for CRPC and four regimens have shown some survival benefit, those survival prolongations have been modest and unfortunately all patients will eventually progress. Thus, there is a need for new agents and regimens for this disease. 2-(2,4-Difluoro-phenyl)-4,5,6,7-tetrafluoro-1H-isoindole-1,3(2H)-dione (CPS49) is a member of a class of redox-reactive thalidomide analogs that show selective killing of leukemic cells by increasing intracellular reactive oxygen species (ROS) and targeting multiple transcriptional pathways. Flavopiridol is a semisynthetic flavonoid that inhibits cyclin dependent kinases and also provokes lethality against leukemic cells. We previously found that CPS49 and flavopiridol combination induced selective cytotoxicity associated with mitochondrial dysfunction and elevations of ROS in leukemic cells ranging from additive to synergistic activity at low micromolar concentrations. The goal of this study was to investigate the selectivity and efficacy of CPS49-flavopiridol combination in prostate cancer preclinical models. Our results showed that flavopiridol enhanced CPS49 cytotoxicity in all human prostate tumor cell lines analyzed (PC3, C4-2, LNCaP and 22RV1); however non tumor cell lines (293HEK and MCF10) were resistant to the tested doses. Furthermore, it was previously reported, high doses of flavopiridol (10 μM) or CPS49 (12 μM) were needed to inhibit tumor growth in PC3 xenograft mice compared with vehicle treated mice. Here, we demonstrated that combining these two agents, antitumor activity was synergistically enhanced with low doses. Injecting subcutaneously PC3 cells in nu/nu mice, we found that CPS49-flavopiridol administration reduced tumor volume approximately 83% after 2 weeks of co-treatment and 54% after 1 week of low dose flavopiridol pretreatment and 2 weeks of drug combination. In addition, we performed RT-qPCR array containing 26 genes from PC3 cells exposed to CPS49 and flavopiridol combination. We determined that this treatment shut down the expression of several genes involved in cell cycle, DNA damage and tumor progression. Histological analysis of xenograft PC3 tumor samples showed extensive areas of necrosis induced by the treatment. Furthermore, we assessed the efficacy of CPS49 in combination with paclitaxel (docetaxel analog). All the prostate tumor cell lines tested were highly sensitive to this combination. However, this combination did not reduce the tumor volume in PC3 xenografts. These results indicate that the CPS49 and flavopiridol is a promising new alternative for the treatment of CRPC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2340. doi:1538-7445.AM2012-2340

Prostate cancer metastasis is well characterized by its tropism to the bone with metastatic lesions being typically osteoblastic. Osteoblasts produce factors that promote growth and survival of prostate cancer cells, but the molecular nature of this interaction is still unknown. Previous reports from our laboratory documented that heme oxygenase-1 (HO-1) is expressed in primary prostate carcinomas and is localized in the nucleus. Recently, the involvement of HO-1 in bone metabolism has been reported. The aim of this study is to investigate the role of HO-1 in the interaction between prostate cancer cells and bone. We analyzed the expression of HO-1 by immunohistochemistry using a tissue microarray generated from 12 castrate-resistant prostate cancer specimens (MDA Anderson Cancer Center), growing as xenografts in male CB17 SCID wild or castrated mice. Each of these tumors led to clinically relevant biological models to study human prostate cancer progression. All samples showed cytoplasmic HO-1 staining of varying intensity. Intense positive nuclear staining was also detected in 3/5 tumors with neuroendocrine morphology. HO-1 expression was correlated with other markers such as PSA, AR and Ki-67 expression. Co-cultures of the osteolytic PC3 cancer cell line with PMO (primary mice osteoblasts) demonstrated that HO-1 induction in PC3 cells abolished the PC3-induced loss of osteoblasts and significantly increased Dickkopf-1 expression in tumor cells. Furthermore, using PC3-PMO co-cultures, we found that HO-1 induction in prostate cancer cells increased mRNA levels of Runx-2 and Cyclin D1 and diminished β-catenin protein expression in PMO. These results clearly indicate the involvement of HO-1 in the interaction between prostate cancer cells and bone. The study of the molecular mechanisms of this interaction will provide effective therapeutic interventions. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5260. doi:10.1158/1538-7445.AM2011-5260

Prostate cancer (PCa) is the second leading cause of cancer-associated death in men. The metastatic spread of PCa cells and the ability to survive when reaching the metastatic nitch is affected by growth factors, chemokines, angiogenic factors and hormones. Heme oxygenase-1 (HO-1), the inducible isoform of the rate-limiting enzyme in heme degradation, counteracts oxidative and inflammatory damage. Here we investigated its nuclear translocation in androgen sensitive (MDAPCa2b and LNCaP) and insensitive (PC3) PCa cell lines. Our results show that endogenous levels of HO-1 are markedly lower in PC3 compared to MDAPCa2b and LNCaP. Hemin treatment, a potent and specific inducer of HO-1, increased protein levels with a resulting nuclear translocation in PCa cell lines. Stable transfection of HO-1 in PC3 (PC3HO-1) also showed a significant nuclear translocation. Furthermore, human prostate cancer PC3HO-1 cells growing subcutaneously in athymic nude mice showed significant HO-1 nuclear staining (detected by immunohistochemsitry and immunofluorescence) compared to PC3pcDNA3 xenografts. Using RT-qPCR-generated gene array we observed a set of inflammatory and angiogenic genes up- or down-regulated in response to HO-1 overexpression, identifying VEGFA as a novel downstream target of HO-1. HO-1 modulation limited the metastatic potential of neoplastic cells by down-regulating VEGFA production. An in vivo angiogenic assay also demonstrated that PC3HO-1 tumors presented less neovascularization than tumors derived from control cells, giving further evidence to support HO-1 anti-angiogenic function. These results implicate for the first time HO-1 in the regulation of key proinflammatory factors, involved in PCa progression. Taken together our results suggest that HO-1 may be a potential target for therapeutic interventions. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-245.

Experimental autoimmune orchitis (EAO) induced in Swiss mice could be reduced by means of the utilization of micronized frustules of fossil diatoms (DS) containing 54% of SiO2. Experimental mice were sensitized with testicular Antigen (Ag) in Complete Freund’s Adjuvant (CFA) inoculated twice, on day 0 and day 21. 100 μg of DS suspension was inoculated into sensitized mice 10 times, once every 4 days, subcutaneously, starting on day 7 after the first Ag inoculation. Mice receiving the DS treatment showed a diminution of the delayed hypersensitivity reaction, lower antibody titer and decreased incidence of testicular injury as well as reduced grade and extension of the lesions. Possible explanation of these results would suggest alteration of monocyte and/or macrophage normal behaviour as well as alteration of antibody synthesis by different mechanisms.

The non-metastatic murine mammary adenocarcinoma M3 and its metastatic variant MM3 were used to evaluate the role of intratumoral necrosis in cell detachment and metastasis. Accelular extracts from necrotic areas of both tumors increased in vitro cellular detachment from M3 but not from MM3 fragments. Furthermore, the in vivo inoculation of the necrotic extracts within non-metastatic M3 tumors gave rise to pulmonary metastases. Histological studies revealed in M3 a central necrosis limited by an uninterrupted peripheral ring of well preserved cells, while in MM3 necrotic and non-necrotic areas alternated. It is concluded that the distribution of necrosis within the primary tumor by facilitating cell detachment is, at least in part, responsible for the development of metastases.

Various immunization assays were used to demonstrate the lack of immunogenicity of three BALB/c tumours of spontaneous origin and of a fourth one resulting from foreign body tumorigenesis. All four tumours inhibited the growth of a second implant of the same tumour into the contralateral flank. In our tumour models "concomitant immunity" (1) was not mediated by macrophage or T-cell dependent immune reactions: both thymectomized BALB/c and nude mice (treated or untreated with silica) gave the same results as intact mice; (2) showed some degree of non-specificity, inhibiting the growth of a different tumour in 3/4 cases; though, the existence of a specific component could not be discarded; (3) was proportional to the volume of the primary tumour at the time of the second challenge; (4) was dependent on actively growing primary tumour, not being obtained with progressively increasing daily inocula of irradiated tumour cells; (5) was detectable in an actively growing secondary tumour; recurrent growth after partial surgical excision was inhibited and (6) involved cytostasis of the secondary tumour: a syngeneic graft of the overlying skin led to tumour growth while histological studies revealed the presence of viable tumour cells. It is postulated that "concomitant immunity" or resistance can be generated without the active participation of the immune system and that tumour-related factors are, in certain cases, responsible for blocking the growth of secondary tumours. Images Figure 5

Twenty-eight (1.69%) cases of primary synchronous bilateral breast cancer (PSBC) out of 1,654 new cases were studied. PSBC compared with unilateral cases had a significantly higher (p less than 0.001) first degree family history of breast cancer; high frequency of subareolar location; no predominance of lobular and non-invasive types; no significantly different percentage of pathological stage I presentation. As there is no complete agreement on what constitutes a PSBC, studies should be carried out to formulate a more precise definition of this entity.

The presence and distribution of cytokeratins (CK) have been investigated using an epidermal keratin antiserum in various dilutions and the PaP (peroxidase-antiperoxidase) and avidin-biotin-peroxidase (ABC) immunohistochemical methods. A total of 44 samples of prostatic tissue were divided into alcohol-fixed (22 cases) and formaldehyde-fixed (22 cases). Each group included 12 non-malignant lesions (hyperplasias and prostatitis) and 10 adenocarcinomas. The best results were achieved with the ABC method in alcohol-fixed tissues, while formaldehyde-fixed tissues gave poor staining despite the use of different enzymes to unmask antigenic determinants. With similar dilutions of the specific antiserum the PaP method gave less intense staining. Cytokeratins were detected in basal and columnar cells, in areas of transitional and squamous metaplasia and in normal transitional epithelium. Columnar cells showed strong staining in the supranuclear portion. Adenocarcinomas gave positive staining for cytokeratins varying from weak to strong. The intensity of staining showed no correlation with the degree of differentiation of the tumor. Different degrees of intensity were frequently observed within the same tumor. High dilutions of the specific antiserum (greater than 1/400) failed to stain carcinomas or stained them poorly, whereas they still stained normal or hyperplastic tissues. Gland-forming tumors showed a highly polarized labelling with the strongest staining in the luminal portion of the cell. The conclusion is that all epithelial prostatic tissues, benign and malignant, express cytokeratins.

Concomitant resistance to a second tumor implant was induced in both conventional and nude BALB/c mice by two nonimmunogenic syngeneic tumors of spontaneous origin, an epidermoid carcinoma and a lymphoid leukemia. In the secondary tumor, which was significantly inhibited by concomitant resistance, histologic examination revealed the presence of well-preserved tumor cells without any sign of necrosis and without any host cell infiltration, contrasting with classical immunologic rejection. Tumor cell proliferation as evaluated by the number of mitoses per high-power field was significantly inhibited in the secondary tumor as compared with the corresponding controls. No effect of concomitant resistance could be detected on primary tumor growth.

Thirty cases of vulvar intraepithelial neoplasia (VIN) were analyzed in order to determine the frequency of association with human papillomavirus (HPV) infection, and the relationship between this association and patient's age, extent of vulvar lesions, and coexistence with cervicovaginal neoplasia. The presence of condyloma or moderate to marked koilocytosis, now considered as morphological evidence of HPV infection, was observed in 66.6% of our cases. A search for HPV antigens, using the peroxidase-antiperoxidase (PAP) method, was performed in 13 selected cases, and positive staining was detected in 3 of them. The presence of HPV infection correlates with a mean age of 48.8 years, 50% of multicentricity of VIN and coexistence with cervical neoplasia in 30% of the cases, as opposed to a mean age of 55.5 years, 10% of multicentricity of VIN and absence of cervical neoplasia in patients without HPV infection. The demonstration of multiple foci of early stromal invasion in a 43-year-old woman, with multicentric VIN lesions associated with HPV infection, indicates that, even in the presence of such clinicopathological features, the risk of developing stromal invasion should be considered. Considerations are made in relation with the presence of HPV antigen in morphological normal epithelium adjacent to the lesion. Therapeutic implications were also investigated.

Prostate cancer (PCa) still ranks as the second most frequently diagnosed cancer and metastatic castrationresistantprostate cancer (CRPC) is a foremost cause of men cancer death around the world. The aim of this work was toinvestigate the selectivity and efficacy of new drug combinations for CRPC. We combined three compounds: paclitaxel(PTX: taxane that inhibits microtubule polymerization); 2-(2,4-Difluoro-phenyl)-4,5,6,7-tetrafluoro-1H-isoindole-1,3(2H)-dione (CPS49; redox-reactive thalidomide analog with anti-angiogenic properties) and flavopiridol (flavo: semisyntheticflavonoid that inhibits cyclin dependent kinases). We assessed CPS49-flavo or -PTX combinations cytotoxicityin a panel of PCa cell lines and PC3 xenografts. We found that CPS49 enhanced flavo or PTX cytotoxicity in human PCacell lines while showed resistance in a non-tumor cell line. Furthermore, xenografts generated by inoculation of humanprostate carcinoma PC3 cells in nu/nu mice showed that CPS49/flavo administration reduced tumor growth both after 2weeks of co-treatment and after 1 week of pretreatment with a low dose of flavo followed by 2 weeks of co-treatment.PTX and CPS49 combination did not significantly reduce tumor growth in PC3 xenografts. Histological analysis ofxenograft PC3 tumor samples from CPS49/flavo combination showed extensive areas of necrosis induced by the treatment.RT-qPCR array containing 23 genes from PC3 cells or PC3 xenografts exposed to CPS49/flavo combinationshowed that this treatment shut down the expression of several genes involved in adhesion, migration or invasion. Insummary, the antitumor activity of CPS49 or flavopiridol was improved by the combination of these compounds and usinghalf dose of that previously reported. Hence, CPS49-flavo combination is a promising new alternative for PCa therapy. Fil: Zalazar, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: de Luca, Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Gardner, Kevin. National Institutes Of Health. Departament Of Healt & Human; Estados Unidos Fil: Figg, William D.. National Institutes of Health; Estados Unidos Fil: Meiss, Roberto. Academia Nacional de Medicina de Buenos Aires; Argentina Fil: Spallanzani, Raúl Germán. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Vallecorsa, Pablo Daniel. Academia Nacional de Medicina de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Elguero, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Cotignola, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Vazquez, Elba Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: de Siervi, Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina