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© The Author(s) 2020, Pancreatic ductal adenocarcinoma (PDAC), the fourth leading cause of cancer death, has a 5-year survival rate of approximately 7–9%. The ineffectiveness of anti-PDAC therapies is believed to be due to the existence of a subpopulation of tumor cells known as cancer stem cells (CSCs), which are functionally plastic, and have exclusive tumorigenic, chemoresistant and metastatic capacities. Herein, we describe a 2D in vitro system for long-term enrichment of pancreatic CSCs that is amenable to biological and CSC-specific studies. By changing the carbon source from glucose to galactose in vitro, we force PDAC cells to utilize OXPHOS, resulting in enrichment of CSCs defined by increased CSC biomarker and pluripotency gene expression, greater tumorigenic potential, induced but reversible quiescence, increased OXPHOS activity, enhanced invasiveness, and upregulated immune evasion properties. This CSC enrichment method can facilitate the discovery of new CSC-specific hallmarks for future development into targets for PDAC-based therapies., We acknowledge and thank Dr. Nuria Malats and Jaime Villarreal from the Spanish National Cancer Research Center (CNIO) for RNA sequencing and analysis, funded by Fondo de Investigaciones Sanitarias (FIS) grant PI18/01347. We thank Patricia Sánchez-Tomero and Marina Ochando-Garmendia for technical assistance and support and Dr. Raúl Sánchez Lanzas for assistance with autophagy experiments. We want to particularly acknowledge the patients and the BioBank Hospital Ramón y Cajal-IRYCIS (PT13/0010/0002) integrated in the Spanish National Biobanks Network for its collaboration and, in particular, Adrián Povo Retana for macrophage isolation. We would also like to thank the Transmission Electron Microscopy Unit Laboratory, part of the UAM Interdepartmental Investigation Service (SIdI); Coral Pedrero for exceptional help with in vivo experiments; and the laboratories of Dr. Amparo Cano and Dr. José González Castaño for reagents and helpful discussions. S.V. was a recipient of an Ayuda de Movilidad del Personal Investigador del IRYCIS, a mobility grant from the Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain, and a pre-doctoral fellowship from the Comunidad de Madrid, Ayudas Para La Contratación De Investigadores Predoctorales Y Posdoctorales (PEJD-2017-PRE/BMD-5062), Madrid, Spain. This study was supported by a Rámon y Cajal Merit Award (RYC-2012-12104) from the Ministerio de Economía y Competitividad, Spain (to B.S.); funding from la Beca Carmen Delgado/Miguel Pérez-Mateo from AESPANC-ACANPAN Spain (to B.S.); a Conquer Cancer Now Grant from the Concern Foundation (Los Angeles, CA, USA) (to B.S.); a Coordinated grant (GC16173694BARB) from the Fundación Asociación Española Contra el Cáncer (AECC) (to B.S.); FIS grants PI18/00757 (to B.S.), PI16/00789 (to M.A.F.-M.), PI18/00267 (to L.G.-B.; co-financed through Fondo Europeo de Desarrollo Regional (FEDER) “Una manera de hacer Europa”); a Miguel Servet award (CP16/00121) (to P.S.); a Max Eder Fellowship of the German Cancer Aid (111746) (to P.C.H.); and the German Research Foundation (DFG, CRC 1279 “Exploiting the human peptidome for Novel Antimicrobial and Anticancer Agents”; to P.C.H.).

Over past decades, targeted therapies and immunotherapy have improved survival and reduced the morbidity of patients with BRAF-mutated melanoma. However, drug resistance and relapse hinder overall success. Therefore, there is an urgent need for novel compounds with therapeutic efficacy against BRAF-melanoma. This prompted us to investigate the antiproliferative profile of a tachykinin-peptide from the Octopus kaurna, Octpep-1 in melanoma.We evaluated the cytotoxicity of Octpep-1 by MTT assay. Mechanistic insights on viability and cellular damage caused by Octpep-1 were gained via flow cytometry and bioenergetics. Structural and pharmacological characterization was conducted by molecular modelling, molecular biology, CRISPR/Cas9 technology, high-throughput mRNA and calcium flux analysis. In vivo efficacy was validated in two independent xerograph animal models (mice and zebrafish).Octpep-1 selectively reduced the proliferative capacity of human melanoma BRAFWe unravel the intrinsic anti-tumoural properties of a tachykinin peptide. This peptide mediates the selective cytotoxicity in BRAF-mutated melanoma in vitro and prevents tumour progression in vivo, providing a foundation for a therapy against melanoma.

Funding Information: We are grateful to Fundação para a Ciência e a Tecnologia, I.P., through MOSTMICRO-ITQB R&D Unit (UIDB/04612/2020, UIDP/04612/2020) and LS4FUTURE Associated Laboratory (LA/P/0087/2020). The NMR spectrometers at CERMAX are integrated in the national NMR Network and partially supported through project 022162. Oscar A. Lenis-Rojas acknowledge national funds through FCT, POPH-Programa Operacional Potencial Humano, and FSE (European Social Fund) for the CEEC 2017 Initiative. Additionally, this work is financed by national funds from FCT—Fundação para a Ciência e a Tecnologia, I.P., in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences—UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy—i4HB. Publisher Copyright: © 2022 by the authors. Ruthenium(II) arene complexes exhibit promising chemotherapeutic properties. In this study, the effect of the counter anion in Ru(II) complexes was evaluated by analyzing the biological effect of two Ru(II) p-cymene derivatives with the 1,10-phenanthroline-5,6-dione ligand of general-formula [(η6-arene)Ru(L)Cl][X] X = CF3SO3 (JHOR10) and PF6 (JHOR11). The biological activity of JHOR10 and JHOR11 was examined in the ovarian carcinoma cell line A2780, colorectal carcinoma cell line HCT116, doxorubicin-resistant HCT116 (HCT116-Dox) and in normal human dermal fibroblasts. Both complexes JHOR10 and JHOR11 displayed an antiproliferative effect on A2780 and HCT116 cell lines, and low cytotoxicity in fibroblasts. Interestingly, JHOR11 also showed antiproliferative activity in the HCT116-Dox cancer cell line, while JHOR10 was inactive. Studies in A2780 cells showed that JHOR11 induced the production of reactive oxygen species (ROS) that trigger autophagy and cellular senescence, but no apoptosis induction. Further analysis showed that JHOR11 presented no tumorigenicity, with no effect in the cellular mobility, as evaluated by thye wound scratch assay, and no anti- or pro-angiogenic effect, as evaluated by the ex-ovo chorioallantoic membrane (CAM) assay. Importantly, JHOR11 presented no toxicity in chicken and zebrafish embryos and reduced in vivo the proliferation of HCT116 injected into zebrafish embryos. These results show that these are suitable complexes for clinical applications with improved tumor cell cytotoxicity and low toxicity, and that counter-anion alteration might be a viable clinical strategy for improving chemotherapy outcomes in multidrug-resistant (MDR) tumors. publishersversion published

Funding Information: This research was funded by national funds through FCT?Funda??o para a Ci?ncia e a Tecnologia, I.P., Project MOSTMICRO-ITQB (UIDB/04612/2020 and UIDP/04612/2020, Project LISBOA-01-0145-FEDER-007660), and national funds through FCT, POPH-Programa Operacional Po-tencial Humano, and FSE (European Social Fund) for the CEEC 2017 Initiative CEECIND/04566/2017. Additionally, this work was supported by the Portuguese Foundation for Science and Technology (FCT?Funda??o para a Ci?ncia e a Tecnologia) for funding through projects PEst 2015 2020, UID/Multi/04349/2013, RECI/QEQ-QIN/0189/2012, and UID/QUI/00100/2020. This work was financed by national funds from FCT?Funda??o para a Ci?ncia e a Tecnologia, I.P., in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences?UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy?i4HB. The NMR spectrometers at CERMAX are integrated with the national NMR Network and partially supported through project 022162. Funding Information: Funding: This research was funded by national funds through FCT–Fundação para a Ciência e a Tecnologia, I.P., Project MOSTMICRO-ITQB (UIDB/04612/2020 and UIDP/04612/2020, Project LISBOA-01-0145-FEDER-007660), and national funds through FCT, POPH-Programa Operacional Po-tencial Humano, and FSE (European Social Fund) for the CEEC 2017 Initiative CEECIND/04566/2017. Additionally, this work was supported by the Portuguese Foundation for Science and Technology (FCT—Fundação para a Ciência e a Tecnologia) for funding through projects PEst 2015 2020, UID/Multi/04349/2013, RECI/QEQ-QIN/0189/2012, and UID/QUI/00100/2020. This work was financed by national funds from FCT—Fundação para a Ciência e a Tecnologia, I.P., in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences—UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy—i4HB. The NMR spectrometers at CERMAX are integrated with the national NMR Network and partially supported through project 022162. Funding Information: Acknowledgments: This work was funded by national funds through FCT—Fundação para a Ciência e a Tecnologia, I.P., Project MOSTMICRO-ITQB (UIDB/04612/2020 and UIDP/04612/2020, Project LISBOA-01-0145-FEDER-007660). Additionally, this work was supported by the Applied Molecular Biosciences Unit—UCIBIO, which is financed by national funds from FCT (UIDP/04378/2020 and UIDB/04378/2020). The NMR spectrometers at CERMAX are integrated with the national NMR Network and partially supported through project 022162. Oscar A. Lenis-Rojas acknowledge national funds through FCT, POPH—Programa Operacional Potencial Humano, and FSE (European Social Fund) for the CEEC 2017 Initiative. Jhonathan Angel Araujo Fernández acknowledge Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES) and the program CAPES/PRINT Proc. 88887.470075/2019-00. We acknowledge I. Ferreira for preliminary viability testing. We also thank the Analytic Services of ITQB and C. Almeida for elemental analysis. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. Made available in DSpace on 2022-01-28T00:27:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-09-12 publishersversion published

Cancer progression requires cells surrounding tumors be reeducated and activated to support tumor growth. Oncogenic signals from malignant cells directly influence stromal composition and activation, but the factors mediating this communication are still not well understood. We have previously shown that the transcription factor POU class 1 homeobox 1 (POU1F1), also known as Pit-1, induces profound changes on neoplastic cell-autonomous processes favoring metastasis in human breast cancer. Here we describe for the first time Pit-1-mediated paracrine actions on macrophages in the tumor microenvironment by using cell lines in vitro, zebrafish and mouse models in vivo, and samples from human breast cancer patients. Through the release of CXCL12, Pit-1 in tumor cells was found to mediate the recruitment and polarization of macrophages into tumor-associated macrophages (TAMs). In turn, TAMs collaborated with tumor cells to increase tumor growth, angiogenesis, extravasation and metastasis to lung. Our data reveal a new mechanism of cooperation between tumor cells and macrophages favoring metastasis and poor clinical outcome in human breast cancer, which suggests that Pit-1 and CXCL12 should be further studied as potential prognostic and therapeutic indicators. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The human cancer cell xenograft in zebrafish embryos has become a very useful preclinical tool in oncology research. While many anticancer drugs have been assayed with this model, few studies regarding the toxicity limits of these drugs for the host have been addressed. Here, we evaluated the acute toxicity of five approved and routinely used human anticancer drugs embracing different mechanism action types: Carboplatin (CarboPt), Irinotecan (IT), Doxorubicin (DOX), Paclitaxel (PT) and Chloroquine (CQ). They were tested in zebrafish embryos using the Fish Embryo Acute Toxicity (FET) test at 0 and 72 hours per fertilization (hpf). Additionally, we compared those results with in vitro toxicity assays and could find notable differences between both models. Our results indicate that the toxicity data of a compound evaluated in vitro and in a FET test at 0 hpf do not guarantee a reliable toxicity determination for performing xenografts in zebrafish, being necessary additional toxicity studies using 72 hpf embryos, the starting point of drug treatment in this kind of preclinical assays.

© The Author(s) 2021., [Background]: Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal cancer, requiring novel treatments to target both cancer cells and cancer stem cells (CSCs). Altered splicing is emerging as both a novel cancer hallmark and an attractive therapeutic target. The core splicing factor SF3B1 is heavily altered in cancer and can be inhibited by Pladienolide-B, but its actionability in PDAC is unknown. We explored the presence and role of SF3B1 in PDAC and interrogated its potential as an actionable target. [Methods]: SF3B1 was analyzed in PDAC tissues, an RNA-seq dataset, and publicly available databases, examining associations with splicing alterations and key features/genes. Functional assays in PDAC cell lines and PDX-derived CSCs served to test Pladienolide-B treatment effects in vitro, and in vivo in zebrafish and mice. [Results]: SF3B1 was overexpressed in human PDAC and associated with tumor grade and lymph-node involvement. SF3B1 levels closely associated with distinct splicing event profiles and expression of key PDAC players (KRAS, TP53). In PDAC cells, Pladienolide-B increased apoptosis and decreased multiple tumor-related features, including cell proliferation, migration, and colony/sphere formation, altering AKT and JNK signaling, and favoring proapoptotic splicing variants (BCL-XS/BCL-XL, KRASa/KRAS, Δ133TP53/TP53). Importantly, Pladienolide-B similarly impaired CSCs, reducing their stemness capacity and increasing their sensitivity to chemotherapy. Pladienolide-B also reduced PDAC/CSCs xenograft tumor growth in vivo in zebrafish and in mice. [Conclusion]. SF3B1 overexpression represents a therapeutic vulnerability in PDAC, as altered splicing can be targeted with Pladienolide-B both in cancer cells and CSCs, paving the way for novel therapies for this lethal cancer., This work has been supported by Spanish Ministry of Economy [MINECO; BFU2016–80360-R (to JPC)] and Ministry of Science and Innovation [MICINN; PID2019-105201RB-I00 (to JPC), PID2019-105564RB-I00 (to RML)]. Instituto de Salud Carlos III, co-funded by European Union (ERDF/ESF, “Investing in your future”) [FIS Grants PI17/02287 and PI20/01301 (to MDG), PI18/00757 (to BS,Jr); DTS Grant DTS20/00050 (to RML)); Postdoctoral Grant Sara Borrell CD19/00255 (to AIC); Predoctoral contract FI17/00282 (to EAP)]. Coordinated grant (GC16173694BARB) from the Fundación Asociación Española Contra el Cáncer (AECC) (to BS,Jr). Spanish Ministry of Universities [Predoctoral contracts FPU14/04290 (to SPA); FPU16/06190 (to VHA); FPU18/02275 (to RBE)]. Boehringer Ingelheim Fonds travel grant (EAP). Junta de Andalucía (BIO0139). GETNE2016 and GETNE2019 Research grants (to JPC); and CIBERobn. Associazione Italiana Ricerca Cancro (AIRC 5×1000 n. 12182); Fondazione Italiana Malattie Pancreas – Ministero Salute [FIMPCUP_J38D19000690001]; Fondazione Cariverona: Oncology Biobank Project “Antonio Schiavi” (prot.203885/2017).

Despite being frequently observed in cancer cells, chromosomal instability (CIN) and its immediate consequence, aneuploidy, trigger adverse effects on cellular homeostasis that need to be overcome by anti-stress mechanisms. As such, these safeguard responses represent a tumor-specific Achilles heel, since CIN and aneuploidy are rarely observed in normal cells. Recent data have revealed that epitranscriptomic marks catalyzed by RNA-modifying enzymes change under various stress insults. However, whether aneuploidy is associated with such RNA modifying pathways remains to be determined. Through an in silico search for aneuploidy biomarkers in cancer cells, we found TRMT61B, a mitochondrial RNA methyltransferase enzyme, to be associated with high levels of aneuploidy. Accordingly, TRMT61B protein levels are increased in tumor cell lines with an imbalanced karyotype as well as in different tumor types when compared to control tissues. Interestingly, while TRMT61B depletion induces senescence in melanoma cell lines with low levels of aneuploidy, it leads to apoptosis in cells with high levels. The therapeutic potential of these results was further validated by targeting TRMT61B in transwell and xenografts assays. We show that TRM61B depletion reduces the expression of several mitochondrial encoded proteins and limits mitochondrial function. Taken together, these results identify a new biomarker of aneuploidy in cancer cells that could potentially be used to selectively target highly aneuploid tumors.

Published studies show that most of the human cancer xenograft studies in zebrafish embryos have used incubation temperatures in the range of 32&ndash, 34 &deg, C for 3&ndash, 6 days post-injection, trying to find a compromise temperature between the zebrafish embryos (28 &deg, C) and the human injected cells (37 &deg, C). While this experimental setup is widely used, a question remains: is possible to overcome the drawbacks caused by a suboptimal temperature for the injected cells? To clarify the effect of temperature and injected cells on the host, in this study, we analyzed the development and health of the last in response to different temperatures in the presence or absence of injected human cancer cells. Comparing different incubation temperatures (28, 34 and 36 &deg, C), we determined morphological abnormalities and developmental effects in injected and non-injected embryos at different time points. Besides this, the expression of selected genes was determined by qPCR to determine temperature affected metabolic processes in the embryos. The results indicate that an incubation temperature of 36 &deg, C during a period of 48 h is suitable for xenotransplantation without morphological or metabolic changes that could be affecting the host or the injected cells, allowing them to proliferate near their optimal temperature.

This article belongs to the Special Issue Human Cancer Modeling in Zebrafish to Improve Our Understanding and Treatment., The first steps towards establishing xenografts in zebrafish embryos were performed by Lee et al., 2005 and Haldi et al., 2006, paving the way for studying human cancers using this animal species. Since then, the xenograft technique has been improved in different ways, ranging from optimizing the best temperature for xenografted embryo incubation, testing different sites for injection of human tumor cells, and even developing tools to study how the host interacts with the injected cells. Nonetheless, a standard protocol for performing xenografts has not been adopted across laboratories, and further research on the temperature, microenvironment of the tumor or the cell–host interactions inside of the embryo during xenografting is still needed. As a consequence, current non-uniform conditions could be affecting experimental results in terms of cell proliferation, invasion, or metastasis; or even overestimating the effects of some chemotherapeutic drugs on xenografted cells. In this review, we highlight and raise awareness regarding the different aspects of xenografting that need to be improved in order to mimic, in a more efficient way, the human tumor microenvironment, resulting in more robust and accurate in vivo results., Consellería de Educación, Universidade e Formación Profesional (ED431C 2018/28).

Consistent with their diverse pharmacology, peptides derived from venomous animals have been developed as drugs to treat disorders as diverse as hypertension, diabetes and chronic pain. Melanoma has a poor prognosis due in part to its metastatic capacity, warranting further development of novel targeted therapies. This prompted us to examine the anti-melanoma activity of the spider peptides gomesin (AgGom) and a gomesin-like homolog (HiGom). AgGom and HiGom dose-dependently reduced the viability and proliferation of melanoma cells whereas it had no deleterious effects on non-transformed neonatal foreskin fibroblasts. Concordantly, gomesin-treated melanoma cells showed a reduced G0/G1 cell population. AgGom and HiGom compromised proliferation of melanoma cells via activation of the p53/p21 cell cycle check-point axis and the Hippo signaling cascade, together with attenuation of the MAP kinase pathway. We show that both gomesin peptides exhibit antitumoral activity in melanoma AVATAR-zebrafish xenograft tumors and that HiGom also reduces tumour progression in a melanoma xenograft mouse model. Taken together, our data highlight the potential of gomesin for development as a novel melanoma-targeted therapy This work was supported by Perpetual IMPACT Grant IDIPAP2015/1585 (to J.J.M.), Discovery Grants DP1095728 (to J.J.M.) and DP130103813 (to G.F.K.) from the Australian Research Council, and by QIMR Berghofer Medical Research Institute crowd funding and salary support (to M.P.I.). M.P.I. is a “Marie Curie” AMAROUT Fellow. M.A.F.R. is a fellow supported by the Talent Program from the Madrid Government of Spain (Grant No. T1-BIO-1854 to M.A.F.R.). J.J.M. is supported by a NHMRC Career Development Fellowship (APP1131732) and G.F.K. by a NHMRC Principal Research Fellowship (APP1136889) SI

Traditionally, studies to address the characterization of mechanisms promoting tumor aggressiveness and progression have been focused only on primary tumor analyses, which could provide relevant information but have limitations to really characterize the more aggressive tumor population. To overcome these limitations, circulating tumor cells (CTCs) represent a noninvasive and valuable tool for real-time profiling of disseminated tumor cells. Therefore, the aim of the present study was to explore the value of CTC enumeration and characterization to identify markers associated with the outcome and the aggressiveness of triple-negative breast cancer (TNBC). For that aim, the CTC population from 32 patients diagnosed with TNBC was isolated and characterized. This population showed important cell plasticity in terms of expression of epithelia/mesenchymal and stemness markers, suggesting the relevance of epithelial to mesenchymal transition (EMT) intermediate phenotypes for efficient tumor dissemination. Importantly, the CTC signature demonstrated prognostic value to predict the patients&rsquo, outcome and pointed to a relevant role of tissue inhibitor of metalloproteinases 1 (TIMP1) and androgen receptor (AR) for TNBC biology. Furthermore, we also analyzed the usefulness of the AR and TIMP1 blockade to target TNBC proliferation and dissemination using in vitro and in vivo zebra fish and mouse models. Overall, the molecular characterization of CTCs from advanced TNBC patients identifies highly specific biomarkers with potential applicability as noninvasive prognostic markers and reinforced the value of TIMP1 and AR as potential therapeutic targets to tackle the most aggressive breast cancer.

The zebrafish model can play a role in education because of its suitability for manipulation and attractiveness to students compared to traditional lecture-based instruction. Furthermore, zebrafish offer advantages over other model species. Seeing as fewer and fewer students are entering science degree programs, this project has been developed to encourage scientific vocations among secondary school students. To do so, an aquarium was given to 114 schools so that they could look after adult zebrafish, mate them, and visualize embryo development. For training on more sophisticated techniques, a virtual tool was developed to simulate a real genetics laboratory on a personal computer. Results based on teachers' feedback indicate that the students were fully dedicated to the project and achieved better understanding of genetic concepts and techniques. These results demonstrate the potential of alternative teaching methods for engaging students in science learning.

This article belongs to the Special Issue Liquid Biopsy., [Background]: Recent studies showed a relevant role of hematogenous spread in ovarian cancer and the interest of circulating tumor cells (CTCs) monitoring as a prognosis marker. The aim of the present study was the characterization of CTCs from ovarian cancer patients, paying special attention to cell plasticity characteristics to better understand the biology of these cells., [Methods]: CTCs isolation was carried out in 38 patients with advanced high-grade serous ovarian cancer using in parallel CellSearch and an alternative EpCAM-based immunoisolation followed by RT-qPCR analysis to characterize these cells., [Results]: Epithelial CTCs were found in 21% of patients, being their presence higher in patients with extraperitoneal metastasis. Importantly, this population was characterized by the expression of epithelial markers as MUC1 and CK19, but also by genes associated with mesenchymal and more malignant features as TIMP1, CXCR4 and the stem markers CD24 and CD44. In addition, we evidenced the relevance of TIMP1 expression to promote tumor proliferation, suggesting its interest as a therapeutic target., [Conclusions]: Overall, we evidenced the utility of the molecular characterization of EpCAM+ CTCs from advanced ovarian cancer patients to identify biomarkers with potential applicability for disseminated disease detection and as therapeutic targets such as TIMP1., Part of this research was supported by CIBERONC funds (CB16/12/00328).

Background: Zebrafish (Danio rerio) is a model organism that has emerged as a tool for cancer research, cancer being the second most common cause of death after cardiovascular disease for humans in the developed world. Zebrafish is a useful model for xenotransplantation of human cancer cells and toxicity studies of different chemotherapeutic compounds in vivo. Compared to the murine model, the zebrafish model is faster, can be screened using high-throughput methods and has a lower maintenance cost, making it possible and affordable to create personalized therapies. While several methods for cell proliferation determination based on image acquisition and quantification have been developed, some drawbacks still remain. In the xenotransplantation technique, quantification of cellular proliferation in vivo is critical to standardize the process for future preclinical applications of the model. Methods: This study improved the conditions of the xenotransplantation technique - quantification of cellular proliferation in vivo was performed through image processing with our ZFtool software and optimization of temperature in order to standardize the process for a future preclinical applications. ZFtool was developed to establish a base threshold that eliminates embryo auto-fluorescence and measures the area of marked cells (GFP) and the intensity of those cells to define a 'proliferation index'. Results: The analysis of tumor cell proliferation at different temperatures (34 °C and 36 °C) in comparison to in vitro cell proliferation provides of a better proliferation rate, achieved as expected at 36°, a maintenance temperature not demonstrated up to now. The mortality of the embryos remained between 5% and 15%. 5- Fluorouracil was tested for 2 days, dissolved in the incubation medium, in order to quantify the reduction of the tumor mass injected. In almost all of the embryos incubated at 36 °C and incubated with 5-Fluorouracil, there was a significant tumor cell reduction compared with the control group. This was not the case at 34 °C. Conclusions: Our results demonstrate that the proliferation of the injected cells is better at 36 °C and that this temperature is the most suitable for testing chemotherapeutic drugs like the 5-Fluorouracil. Fil: Cabezas-Sainz, Pablo. Universidad de Santiago de Compostela; España Fil: Guerra-Varela, Jorge. Universidad de Santiago de Compostela; España Fil: Carreira, María J.. Universidad de Santiago de Compostela; España Fil: Mariscal, Javier. Universidad de Santiago de Compostela; España Fil: Roel, María. Universidad de Santiago de Compostela; España Fil: Rubiolo, Juan Andrés. Universidad de Santiago de Compostela; España Fil: Sciara, Andres Angel. Universidad Nacional de Rosario; Argentina. Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET) - Facultad de Bioquímica y Ciencias Farmacéuticas, ; Argentina Fil: Abal, Miguel. Universidad de Santiago de Compostela; España Fil: Botana, Luis M.. Universidad de Santiago de Compostela; España Fil: López, Rafael. Universidad de Santiago de Compostela; España Fil: Sánchez, Laura. Universidad de Santiago de Compostela; España

// Maria Roel 1 , Juan A. Rubiolo 1 , Jorge Guerra-Varela 2 , Siguara B. L. Silva 3, 4 , Olivier P. Thomas 3, 5 , Pablo Cabezas-Sainz 2 , Laura Sanchez 2 , Rafael Lopez 6 , Luis M. Botana 1 1 Department of Pharmacology, Universidade de Santiago de Compostela, Campus Lugo, 27002 Lugo, Spain 2 Department of Genetics, Universidade de Santiago de Compostela, Campus Lugo, 27002 Lugo, Spain 3 Geoazur, UMR Universite Nice Sophia Antipolis-CNRS-IRD-OCA, 06560 Valbonne, France 4 Laboratoire de Pharmacognosie, UMR CNRS 8076 BioCIS, LabEx LERMIT, Universite Paris-Sud, Faculte de Pharmacie, 92290 Châtenay-Malabry, France 5 School of Chemistry, Marine Biodiscovery, National University of Ireland Galway, SW4 Galway, Ireland 6 Translational Medical Oncology, Health Research Institute of Santiago (IDIS), Complexo Hospitalario Universitario de Santiago de Compostela (SERGAS), 15706 Santiago de Compostela, Spain Correspondence to: Luis M. Botana, email: luis.botana@usc.es Keywords: crambescidins, cell cycle inhibition, apoptosis, zebrafish xenograft model, cancer treatment Received: March 13, 2016 Accepted: September 27, 2016 Published: November 04, 2016 ABSTRACT The marine environment constitutes an extraordinary resource for the discovery of new therapeutic agents. In the present manuscript we studied the effect of 3 different sponge derived guanidine alkaloids, crambescidine-816, -830, and -800. We show that these compounds strongly inhibit tumor cell proliferation by down-regulating cyclin-dependent kinases 2/6 and cyclins D/A expression while up-regulating the cell cyclin-dependent kinase inhibitors -2A, -2D and -1A. We also show that these guanidine compounds disrupt tumor cell adhesion and cytoskeletal integrity promoting the activation of the intrinsic apoptotic signaling, resulting in loss of mitochondrial membrane potential and concomitant caspase-3 cleavage and activation. The crambescidin 816 anti-tumor effect was fnally assayed in a zebrafish xenotransplantation model confirming its potent antitumor activity against colorectal carcinoma in vivo . Considering these results crambescidins could represent promising natural anticancer agents and therapeutic tools.

Zebrafish is establishing itself as a powerful animal model for understanding human disease, including cancer. Xenotransplantation of human cancer cells into zebrafish is becoming an attractive research tools for studying cancer behaviour, both for established lines and primary tumours, however, its utility as a model for cancer stem cells (CSCs) is still in its infancy. In addition, only when the differences between primary tumours and established cancer cell lines are minimized will we be truly one step closer to developing biologically relevant personalized medicine platforms for cancer. To address these two limitations, we set out to achieve a deeper behavioral understanding of pancreatic CSCs inside the zebrafish embryo. The main methodology of this study was focused on the xenotransplantation of human primary pancreatic ductal adenocarcinoma (PDAC) cells (185 scd line) into zebrafish embryos using two different conditions: adherent cells (non-CSCs) vs sphere-derived cells (CSCs). Marked with a lipophilic dye, cells were injected into zebrafish embryos and incubated at 36ºC during 48h/72h to assess the proliferation of the injected cells. Self-developed Matlab software was used to analyze the intensity and area of the injected cells in order to give a ‘proliferation ratio’. Results obtained indicated that the sphere-derived cells proliferated and migrated at a higher rate than adherent cells. This is likely due to the different CSC content present between the two conditions tested: adherent pancreatic 185 cells contain 1% CSCs versus the 15% enrichment of CSCs in sphere-derived 185 cells. Apart from the differential CSC content, we also hypothesize that the 3D environment afforded by the yolk sac of the zebrafish embryo additionally favors the expansion of CSCs. Importantly, similar results were obtained with CSCs isolated via FACsorting, using autofluorescence as a marker for CSCs. This work not only contributes to the behavioral understanding of pancreatic CSCs using the zebrafish model organism but more importantly concludes that 1) PDAC CSC proliferation and migration can be studied in zebrafish, 2) the zebrafish model represents a potentially powerful surrogate model for the study of PDAC CSC biology in vivo, and 3) this model can potentially be adapted for to test chemotherapeutics that specifically target PADC CSCs, the cell type considered to be the most chemoresistant and tumorigenic in pancreatic cancer. Citation Format: Laura E. Sanchez, Pablo Cabezas Sainz, Bruno Sainz, Laura Muinelo, Rafael Lopez. Zebrafish as a model organism to study human pancreatic CSC's [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 804. doi:10.1158/1538-7445.AM2017-804