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Head and neck squamous cell carcinoma (HNSCC) arises from the mucosal lining of the upper aerodigestive tract and display few treatment options in advanced stages. Despite increased knowledge of HNSCC molecular biology, the identification of new players involved in triggering HNSCC recurrence and metastatic disease is needed. We uncover that G‐protein‐coupled receptor kinase‐2 (GRK2) expression is reduced in undifferentiated, high‐grade human HNSCC tumors, whereas its silencing in model human HNSCC cells is sufficient to trigger epithelial‐to‐mesenchymal transition (EMT) phenotypic features, an EMT‐like transcriptional program and enhanced lymph node colonization from orthotopic tongue tumors in mice. Conversely, enhancing GRK2 expression counteracts mesenchymal cells traits by mechanisms involving phosphorylation and decreased functionality of the key EMT inducer Snail1. Our results suggest that GRK2 safeguards the epithelial phenotype, whereas its downregulation contributes to the activation of EMT programs in HNSCC., Our laboratories are supported by Agencia Estatal de Investigación of Spain (grants SAF2014‐55511‐R and SAF2017‐84125‐R to F.M.; SAF2015‐66015‐R and ISCIII PIE15/00081 to J.P.M.; SAF2016‐76504‐R to A.C. and BFU2014‐53128‐R to M.A.N.); CIBERCV‐Instituto de Salud Carlos III, Spain (grant CB16/11/00278 to F.M., co‐funded with European FEDER contribution), CIBERONC‐Instituto de Salud Carlos III (grant CB16/12/00228 and CB16/12/00295 to J.M.P. and A.C., respectively, co‐funded with European FEDER contribution); Instituto de Salud Carlos III, Spain (grant PI14/00201 and PI18/01662 to C.R.; PI18/00263 to R.G.E., co‐funded with European FEDER contribution) and Fundación Ramón Areces (to C.R and F.M.), Swiss National Science Foundation (grant 144637, 153099), Swiss Cancer League (grant KLS 3243‐08‐2013) and Fundacion Anemia de Fanconi (grant 2018/127) to R.G.E.; and Programa de Actividades en Biomedicina de la Comunidad de Madrid‐B2017/BMD‐3671‐INFLAMUNE to F.M. M.S.F. was recipient of a Postdoctoral fellowship from Comunidad de Madrid (PEFD‐2017‐POST/BMD‐4442) and A.A. holds a PhD Fellowship from FPI programme Agencia Estatal de Investigación (PRE2018‐084418). We also acknowledge institutional support to the CBMSO from Fundación Ramón Areces.

Background Exosomes are small membranous vesicles (around 40-130 nm), that have been detected in different biological samples, that play a key role in NSCLC and being relevant in stem cell differentiation as well. The main objective of this study was to analyze the exosomes cargo from NSCLC cell cultures growth in monolayer (2D) and suspension conditions (3D, lung tumorespheres). Methods Cultures were established from NSCLC resected patients and cell lines. Exosomes isolation was performed by ultracentrifugation. Characterization was carried out by NTA, electron microscopy, immunoblot and flow cytometry. Mutational status of EGFR and RAS genes was analyzed by BEAMing dPCR. Transcriptomic analysis has been carried out from exosomal RNA with microarrays, (p ≤ 0.01). Consequently, XAGE1B (significantly expressed gene in exosomes) was analyzed by RTqPCR in 189 paired fresh-frozen tumor and normal tissue samples of resected NSCLC. Prognostic value was assessed by Kaplan‐Meier curves (log rank‐test), considering significant p Results Exosomal characterization through NTA and electron microscopy showed an exosomes size from 108-125 nm. Specific markers were detected by IB and FC. Mutational analysis of EGFR and RAS genes in exosomes shown the same pattern displayed by the origin cells. Transcriptomic analysis showed that the expression of mRNAs, miRNAs and precursors were significantly different between 3D and 2D-derived exosomes. A pathway enrichment was carried out to know in which processes (cancer-related) are involved. Significant differential expression was also found between ADC vs SCC–derived exosomes. Concretely, XAGE1B is overexpressed in ADC-derived exosomes (p = 0.00003). This overexpression in ADC was validated in NSCLC cohort (p = 0.002). Furthermore, it has revealed a significant association with patient prognosis for overall survival in the ADC group (n = 74)(OS 49.8 vs. NR months, p = 0.043). Conclusions Differences in exosomal cargo have been observed between: i) 3D vs. 2D cultures and ii) ADC vs. SCC. In addition, the same mutational pattern was detected in exosomes as compared with parental cells. Therefore, exosomes can be a useful source of biomarkers in NSCLC analysis. Supported by grant GV/2018/026, PI18/00266, & AECC Valencia. Legal entity responsible for the study Fundacion de Investigacion del Hospital General Universitario de Valencia. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.

Non-muscle invasive bladder cancer (NMIBC) represents a crucial problem for the national health care systems due to its high rates of recurrence and the consequent need of frequent follow-ups. Here, gene expression analyses in patients diagnosed as NMIBC were performed to determine those molecular pathways involved in tumor initiation, finding that both MYC and E2F are up regulated and helps to tumor initiation and progression. Our results also support an important involvement of alternative splicing events, modifying key pathways to favour bladder tumor evolution. Finally, since MDM2 showed differential exon usage, mutations in TP53 and its protein expression have been also studied in the same patients. Our data support that recurrence is epigenetically mediated and favoured by an increase protein expression of TP53, which appears more frequently mutated in advanced stages and grades, being associated to a worse prognosis. Therefore, TP53 mutational status could be used as a potential biomarker in the first stages of NMIBC to predict recurrence and prognosis. We express our deepest acknowledgement to patients and their families. The authors also acknowledge the computing resources and technical support provided by Abel Paz-Gallardo and Alfonso Pardo from Extremadura Research Centre for Advanced Technologies (CETA−CIEMAT). This work was supported FEDER cofounded MINECO grant SAF2015-66015-R, ISCIII-RETIC RD12/0036/0009, and PIE15/00076 and CB/16/00228 (to J.M. Paramio); MMF was supported by a Jose Castillejo Fellowship (CAS16/00115).

Metabolism reprogramming is considered a hallmark of cancer. The study of bladder cancer (BC) metabolism could be the key to developing new strategies for diagnosis and therapy. This work aimed to identify tissue and urinary metabolic signatures as biomarkers of BC and get further insight into BC tumor biology through the study of gene-metabolite networks and the integration of metabolomics and transcriptomics data. BC and control tissue samples (n = 44) from the same patients were analyzed by High-Resolution Magic Angle Spinning Nuclear Magnetic Resonance and microarrays techniques. Besides, urinary profiling study (n = 35) was performed in the same patients to identify a metabolomic profile, linked with BC tissue hallmarks, as a potential non-invasive approach for BC diagnosis. The metabolic profile allowed for the classification of BC tissue samples with a sensitivity and specificity of 100%. The most discriminant metabolites for BC tissue samples reflected alterations in amino acids, glutathione, and taurine metabolic pathways. Transcriptomic data supported metabolomic results and revealed a predominant downregulation of metabolic genes belonging to phosphorylative oxidation, tricarboxylic acid cycle, and amino acid metabolism. The urinary profiling study showed a relation with taurine and other amino acids perturbed pathways observed in BC tissue samples, and classified BC from non-tumor urine samples with good sensitivities (91%) and specificities (77%). This urinary profile could be used as a non-invasive tool for BC diagnosis and follow-up.

Epidermal stem cells are responsible for normal tissue homeostasis and contribute to tissue regeneration during injury. Several assays measuring stem cell frequency and function can be used to assess epidermal stem cell potential. However, the ultimate assay that accounts for stemness is the capacity to sustain in vivo long-term tissue regeneration and maintenance. We can use this type of analysis to interrogate whether a specific genetic alteration (e.g., activation or inactivation of any gene thought to be involved in stem cell quiescence or proliferation) confers increased or decreased stem cell potential.

The bidirectional regulation of epithelial–mesenchymal transitions (EMT) is key in tumorigenesis. Rho GTPases regulate this process via canonical pathways that impinge on the stability of cell-to-cell contacts, cytoskeletal dynamics, and cell invasiveness. Here, we report that the Rho GTPase activators Vav2 and Vav3 utilize a new Rac1-dependent and miR-200c-dependent mechanism that maintains the epithelial state by limiting the abundance of the Zeb2 transcriptional repressor in breast cancer cells. In parallel, Vav proteins engage a mir-200c-independent expression prometastatic program that maintains epithelial cell traits only under 3D culture conditions. Consistent with this, the depletion of endogenous Vav proteins triggers mesenchymal features in epithelioid breast cancer cells. Conversely, the ectopic expression of an active version of Vav2 promotes mesenchymal-epithelial transitions using E-cadherin-dependent and independent mechanisms depending on the mesenchymal breast cancer cell line used. In silico analyses suggest that the negative Vav anti-EMT pathway is operative in luminal breast tumors. Gene signatures from the Vav-associated proepithelial and prometastatic programs have prognostic value in breast cancer patients., XRB is supported by grants from the Castilla-León Government (CSI049U16), the Spanish Ministry of Economy and Competitiveness (MINECO) (SAF2015-64556-R), Worldwide Cancer Research (14-1248), the Ramón Areces Foundation, and the Spanish Association against Cancer (GC16173472GARC). MD (BFU2014-52729-P), JMP (SAF2015-66015-R, PIE15/00076), and PMF-S (SAF2014-51813-R) are supported by MINECO grants. Spanish funding is partially supported by the European Regional Development Fund. LFL-M, JC, and SR-F were supported by funding from the Spanish Ministry of Education, Culture and Sports (LFL-M, FPU13/02923) and the MINECO (JC, CD15/00113; SR-F, BES-2013-063573).

// Josefa P. Alameda 1, 2 , Manuel Navarro 1, 2 , Angel Ramirez 1, 2 , Angustias Page 1, 2 , Cristian Suarez-Cabrera 1, 2 , Rodolfo Moreno-Maldonado 3 , Jesus M. Paramio 1, 2 , Maria del Carmen Farina 4 , Marcela Del Rio 5, 6, 7 , Maria Jesus Fernandez-Acenero 8 , Ana Bravo 9 , Maria de los Llanos Casanova 1, 2 1 Molecular Oncology Unit, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Madrid, Spain 2 Molecular Oncology, Institute of Biomedical Investigation University Hospital “12 de Octubre”, Madrid, Spain 3 Present address: SILO Espana, Madrid, Spain 4 Department of Dermatology, Fundacion Jimenez Diaz, Madrid, Spain 5 Epithelial Biomedicine Division, CIEMAT-CIBERER (U714), Madrid, Spain 6 Department of Bioengineering, Carlos III University (UC3M), Leganes, Madrid, Spain 7 Catedra Fundacion Jimenez Diaz (IIS-FJD) of Regenerative Medicine and Tissue Bioengineer, Madrid, Spain 8 Department of Pathology, Hospital Clinico San Carlos, Madrid, Spain 9 Department of Veterinary Clinical Sciences, Faculty of Veterinary Medicine, University of Santiago de Compostela, Lugo, Spain Correspondence to: M. Llanos Casanova, email: llanos.casanova@ciemat.es Keywords: IKKα, keratinocyte differentiation, MMP9, skin, skin cancer Received: July 29, 2016 Accepted: September 29, 2016 Published: October 08, 2016 ABSTRACT IKKα plays a mandatory role in keratinocyte differentiation and exerts an important task in non-melanoma skin cancer development. However, it is not fully understood how IKKα exerts these functions. To analyze in detail the role of IKKα in epidermal stratification and differentiation, we have generated tridimensional (3D) cultures of human HaCaT keratinocytes and fibroblasts in fibrin gels, obtaining human skin equivalents that comprise an epidermal and a dermal compartments that resembles both the structure and differentiation of normal human skin. We have found that IKKα expression must be strictly regulated in epidermis, as alterations in its levels lead to histological defects and promote the development of malignant features. Specifically, we have found that the augmented expression of IKKα results in increased proliferation and clonogenicity of human keratinocytes, and leads to an accelerated and altered differentiation, augmented ability of invasive growth, induction of the expression of oncogenic proteins (Podoplanin, Snail, Cyclin D1) and increased extracellular matrix proteolytic activity. All these characteristics make keratinocytes overexpressing IKKα to be at a higher risk of developing skin cancer. Comparison of genetic profile obtained by analysis of microarrays of RNA of skin equivalents from both genotypes supports the above described findings.

// Clotilde Costa 1, 3 , Mirentxu Santos 1, 2 , Monica Martinez-Fernandez 1, 2 , Corina Lorz 1, 2 , Sara Lazaro 1 , Jesus M. Paramio 1, 2 1 Unidad de Oncologia Molecular, CIEMAT (ed70A), 28040 Madrid, Spain 2 Unidad de Oncologia Molecular y Celular, Instituto de Investigaciones Biomed, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain 3 Present address: Unidad Mixta Roche-Chus, Hospital Universitario, 15706 Santiago de Compostela, Spain Correspondence to: Jesus M. Paramio, email: jesusm.paramio@ciemat.es Mirentxu Santos, email: mirentxu.santos@ciemat.es Keywords: epidermis, Rb, E2F4, mouse, cancer Received: July 16, 2016 Accepted: September 19, 2016 Published: September 30, 2016 ABSTRACT E2F/RB activity is altered in most human tumors. The retinoblastoma family of proteins plays a key role in regulating the progression of the cell cycle from the G1 to S phases. This is achieved through negative regulation of E2F transcription factors, important positive regulators of cell cycle entry. E2F family members are divided into two groups: activators (E2F1-E2F3a) and repressors (E2F3b-E2F8). E2F4 accounts for a large part of the E2F activity and is a main E2F repressor member in vivo . Perturbations in the balance from quiescence towards proliferation contribute to increased mitotic gene expression levels frequently observed in cancer. We have previously reported that combined Rb1 - Rbl1 or Rb1 - E2f1 ablation in epidermis produces important alterations in epidermal proliferation and differentiation, leading to tumor development. However, the possible roles of E2F4 in this context are still to be determined. Here, we show the absence of any discernible phenotype in the skin of mice lacking of E2f4 . In contrast, the inducible loss of Rb1 in the epidermis of E2F4-null mice produced multiple skin abnormalities including altered differentiation and proliferation, spontaneous wounds, carcinoma in situ development and stem cell perturbations. All these phenotypic alterations are associated with extensive gene expression changes, the induction of c-myc and the Akt activation. Moreover the whole transcriptome analyses in comparison with previous models generated also revealed extensive changes in multiple repressive complexes and in transcription factor activity. These results point to E2F4 as a master regulator in multiple steps of epidermal homeostasis in Rb1 absence.

RNA detection in liquid urine biopsy specimens could be an optimal method for noninvasive diagnostic and prognostic procedures in urologic disorders; however, there are no standardized procedures for implementing it in the clinic. We present a systematic evaluation of the best storage conditions and purification methods using four commercially available extraction kits to purify RNA from void urine. We measured different RNA molecules to select good and stable biomarkers and normalizers for analyses in liquid urine biopsy specimens. We have established a new combined procedure for RNA isolation from urine and found good performance in 25 urine samples from healthy volunteers of both sexes. Associations were tested using the t-test for paired samples, and miRNA specimens were selected as the more stable molecules. Stability analysis was performed, and we found miR193a and miR448 as the best normalizers to be used in this biofluid. This is a highly reproducible method that could be used to evaluate urine samples for diagnostic and prognostic purposes.

TPS598 Background: Intravesical Bacillus Calmette-Guerin (BCG) induction + BCG maintenance after transurethral resection (TURBT) is the current standard of care for patients (pt) with high-risk non-muscle invasive bladder cancer (NMIBC). Recurrence rate at 2 years is around 30%, which is clearly unsatisfactory. Programmed death ligand 1 (PD-L1) is a surface glycoprotein that functions as an inhibitor of T-cells and plays a crucial role in suppression of cellular immune response. Atezolizumab is a humanized IgG1 monoclonal antibody targeting PD-L1 and is associated with long-term durable remissions in pts with metastatic urothelial cancer (Powles T. Lancet. 2018). Atezolizumab in combination with standard BCG could be beneficial in pts with NMIBC. BladderGATE (NCT04134000) is a phase Ib-II study aims to evaluate the clinical impact and safety of the combination of Atezolizumab + intravesical BGC (medac strain), including a translational study (microbioma and urobioma) in pts with NMIBC. Methods: Eligible pt have confirmed histopathology of NMIBC, BCG naïve or stopped >3 years ago, WHO PS 0-1, no prior radiation to bladder and adequate hematologic and end-organ function. We propose a de-escalation design to enroll patients to identify DLT and MTD proposed to safety and efficacy expansion cohort. Pt will receive induction BCG, 1 instillation every week (qw) (dose level 0) or BCG, 1/2 instillation qw (dose level -1) + intravenously atezolizumab 1200 mg every 3 w (q3w), during 6 w. After induction, BCG will be administered as maintenance treatment at weeks 12, 24 and 48 and atezolizumab 1200 mg q3w up to 1 year. Pt will be accrued to each dose level in cohorts of 10 pt until the MTD is achieved (the highest dose at which

757 Background: Immune checkpoint inhibitors have increased survival in mRCC across all risk groups. In this new treatment paradigm, inflammatory markers could add prognostic information to the International metastatic Renal Cell Carcinoma Database Consortium (IMDC) model in patients treated with ICI. Methods: We conducted a multicenter retrospective analysis of mRCC patients treated with ICI from 2013 to 2019. Clinical, pathological and laboratory data including blood cell counts were collected. Multivariate Cox-regression models were performed to evaluate the independent prognostic significance of the IMDC score, the derived neutrophil to lymphocyte ratio (dNLR) and LDH at baseline, as well as the inflammatory prognostic index (IPI). Results: A total of 104 patients were included. Of these, 19% were treatment-naïve, 34% had received one previous line of treatment and 47% had received two or more previous lines of treatment. Distribution of IMDC model for favorable, intermediate and poor risk was 23%,57% and 20%. Median OS was 15 months and the disease control rate (DCR) was 51%. The multivariate analysis identified the IMDC risk score, the dNLR and the IPI as independent predictors of OS. In addition, both inflammatory markers, the IPI and the dNLR, were able to improve the prognostic value of the IMDC risk score (p = 0.01 and p = 0.006, respectively). Specifically, in patients with 0 or 1 IMDC risk factors, both the IPI and the dNLR were able to subclassify additional prognostic subgroups (i.e. dNLR > 3 vs ≤3 HR = 3,16; 95% CI; 1.71-5.76). Conclusions: Adding IPI and/or dNLR may add further information about the benefit of ICIs in mRCC patients with 0 or 1 IMDC risk factors. Inflammatory systemic markers may improve the prognostic performance of the IMDC model.[Table: see text]

CYLD is a deubiquitinating enzyme known for its role as a tumor suppressor whose mutation leads to skin appendages tumors and other cancers. In this manuscript we report that the tumor suppressor CYLD, similarly to other renowned tumor suppressor genes, protects from premature aging and cancer. We have generated transgenic mice expressing the mutant CYLDC/S protein, lacking its deubiquitinase function, under the control of the keratin 5 promoter, the K5-CYLDC/S mice. These mice express the transgene in different organs, including those considered to be more susceptible to aging, such as skin and thymus. Our results show that K5-CYLDC/S mice exhibit epidermal, hair follicle, and sebaceous gland alterations; and, importantly, they show signs of premature aging from an early age. Typically, 3-month-old K5-CYLDC/S mice exhibit a phenotype characterized by alopecia and kyphosis, and, the histological examination reveals that transgenic mice show signs of accelerated aging in numerous organs such as skin, thymus, pancreas, liver and lung. Additionally, they spontaneously develop tumors of diverse origin. Over-activation of the NF-κB pathway, along with hyperactivation of Akt, JNK and c-Myc, and chronic inflammation, appear as the mechanisms responsible for the premature aging of the K5-CYLDC/S mice.

Macrophages are major components of the immune infiltration in cancer where they can affect tumor behavior. In the bladder, they play important roles during the resolution of infectious processes and they have been associated with a worse clinical prognosis in bladder cancer. The present review focused on the characteristics of these important immune cells, not only eliciting an innate immune surveillance, but also on their importance during the cancer immunoediting process. We further discuss the potential of targeting macrophages for anticancer therapy, the current strategies and the state of the art as well as the foreseen role on combined therapies on the near future. This review shows how a comprehensive understanding of macrophages within the tumor should translate to better clinical outcome and new therapeutic strategies focusing especially on bladder cancer.

Using Sos1 knockout (Sos1-KO), Sos2-KO, and Sos1/2 double-knockout (Sos1/2-DKO) mice, we assessed the functional role of Sos1 and Sos2 in skin homeostasis under physiological and/or pathological conditions. Sos1 depletion resulted in significant alterations of skin homeostasis, including reduced keratinocyte proliferation, altered hair follicle and blood vessel integrity in dermis, and reduced adipose tissue in hypodermis. These defects worsened significantly when both Sos1 and Sos2 were absent. Simultaneous Sos1/2 disruption led to severe impairment of the ability to repair skin wounds, as well as to almost complete ablation of the neutrophil-mediated inflammatory response in the injury site. Furthermore, Sos1 disruption delayed the onset of tumor initiation, decreased tumor growth, and prevented malignant progression of papillomas in a DMBA (7,12-dimethylbenz[α]anthracene)/TPA (12-O-tetradecanoylphorbol-13-acetate)-induced skin carcinogenesis model. Finally, Sos1 depletion in preexisting chemically induced papillomas resulted also in decreased tumor growth, probably linked to significantly reduced underlying keratinocyte proliferation. Our data unveil novel, distinctive mechanistic roles of Sos 1 and Sos2 in physiological control of skin homeostasis and wound repair, as well as in pathological development of chemically induced skin tumors. These observations underscore the essential role of Sos proteins in cellular proliferation and migration and support the consideration of these RasGEFs as potential biomarkers/therapy targets in Ras-driven epidermal tumors., This study was supported by grants FIS PI16/02137 from ISCIII (MINECO), SA043U16 (UIC 076) from JCyL, and AECC Spain (to E.S.); by MINECO grant SAF2015-66015-R; and by MSyC grants ISCIII-RETIC RD12/0036/0009, PIE 15/00076, and CB/16/00228 (to J.M.P.). This research was cofinanced by FEDER funds

Although Ras genes are frequently mutated in human tumors, these mutations are uncommon in breast cancer. However, many breast tumors show evidences of Ras pathway activation. In this manuscript, we have analyzed and characterized mouse mammary tumors generated by random Sleeping Beauty transposon mutagenesis and identify ERAS -a member of the RAS family silenced in adult tissues- as a new gene involved in progression and malignancy of breast cancer. Forced expression of ERAS in human non-transformed mammary gland cells induces a process of epithelial-to-mesenchymal transition and an increase in stem cells markers; these changes are mediated by miR-200c downregulation. ERAS expression in human tumorigenic mammary cells leads to the generation of larger and less differentiated tumors in xenotransplant experiments. Immunohistochemical, RT-qPCR and bioinformatics analysis of human samples show that ERAS is aberrantly expressed in 8–10% of breast tumors and this expression is associated with distant metastasis and reduced metastasis-free survival. In summary, our results reveal that inappropriate activation of ERAS may be important in the development of a subset of breast tumors. These findings open the possibility of new specific treatments for this subset of ERAS-expressing tumors., This research was supported partially by funds from Fondo Europeo de Desarrollo Regional (FEDER) and by grants from the Spanish Government PI16/00161, PI16/00134, PIE15/00076, PI17/00578, CB/16/00228, CB16/12/00295 and RD12/0036/0009 from Instituto de Salud Carlos III (Ministerio de Economía y Competitividad) and SAF-2015-66015-R from the Ministerio de Economía y Competitividad. Biobanco 1 + 12 is supported by Instituto de Salud Carlos III.

[Background]: MicroRNAs (miRNAs) play a unique role in posttranscriptional regulation of gene expression and control different aspects of skin development, homeostasis, and disease. Although it is generally accepted that thyroid hormone signaling is important in skin pathophysiology, the role of their nuclear receptors (TRs) in cutaneous miRNA expression has yet to be explored., [Methods]: RNAseq was used to compare the skin miRnome of wild-type mice and genetically modified mice lacking both TRα1 and TRβ, the main thyroid hormone binding isoforms. Changes in miRNAs with a crucial role in skin physiopathology were confirmed by stem-loop quantitative polymerase chain reaction in both total skin and isolated keratinocytes, and the levels of their target mRNAs were evaluated by real-time polymerase chain reaction., [Results]: The skin of TRα1/TRβ knockout mice displays altered levels of >50 miRNAs. Among the downregulated species are several miRNAs, including miR-21, miR-31, miR-34, and miR-203, with crucial roles in skin homeostasis. TRα1 appears to be the main isoform responsible for their regulation. Increased levels of gene transcripts previously shown to be bona fide targets of these miRNAs are also found in the skin and keratinocytes of TR-deficient mice. This suggests that multiple miRNAs that are downregulated in the absence of TRs cooperate to regulate gene expression in the skin., [Conclusions]: The miRNAs reduced in TRα1/TRβ knockout mice are known to play crucial roles in epidermal proliferation, hair cycling, wound healing, stem-cell function, and tumor development, all processes altered in the absence of TRs. These results suggest that their regulation could contribute to the skin defects found in these mice and to the skin disorders associated with altered thyroid status in humans., This work was supported by Grants BFU2011-28058, BFU2014-53610-P, and B2017/BMD-3724 to A.A; and SAF2015-66015-R, RD12/0036/0009, PIE 15/00076, and CB/16/00228 to J.M.P.

Background In patients with stage III or IV HGSOC who are not suitable for primary surgery (PDS), 3 cycles of platinum based NACT followed by interval surgery (IDS) and adjuvant chemotherapy is an accepted treatment approach. NACT enhances host immune response by increasing levels of PD1, CTLA4 and PDL1 (Bohm S et al. Clin Cancer Res 2016). Gene expression profiling of tumors has identified prognostic signatures for patient selection with immunotherapy (Ribas A et al. J Clin Oncol 2015). Methods The purpose of this study is to assess the effect of neoadjuvant chemotherapy (NACT) on immune activation in stage IIIC/IV tubo-ovarian high-grade serous carcinoma (HGSOC). We obtained pre- and post-treatment omental biopsies from a total of 45 patients undergoing platinum-based NACT followed by IDS. We measured T-cell density and phenotype, immune activation, and markers of cancer-related inflammation using IHC. Messenger RNA expression was analyzed on the nCounter system using the PanCancer IO360 Panel. Results There was evidence of T-cell activation in omental biopsies after NACT. CD4+ T cells showed enhanced IFNgproduction and antitumor Th1 gene signatures were increased. T-cell activation correlated with therapeutic response to NACT. The CD8 T-cell and CD45RO memory cell density in the tumor microenvironment was unchanged after NACT, but biopsies after a good therapeutic response had significantly fewer FoxP3 + (Treg) cells. Biopsies of good therapeutic responders also showed areduction in a Treg gene signature in post versus pre-NACT samples.Preliminary results according to gene expression of the immune compartment reveal that tumor infiltrating lymphocytes were more abundant in samples from patients showing a good response over those with no or incomplete response to NACT, as well as an increase in gene signatures associated with antigen presentation and Cytokine and Chemokine Signaling. When comparing the expression profiles between samples obtained before or after NACT in patients showing incomplete response,we obtained an expected decreased in cellular proliferation signature. Conclusions NACT may promote an immune modulatory effect that could improve or favour the further use of specific immunotherapy in HGSOC patients. Legal entity responsible for the study Fundacion para la Investigacion 12 de Octubre. Funding Tesaro SL. Disclosure L.M. Manso: Research grant / Funding (self): Tesaro; Advisory / Consultancy: Roche, Novartis, Tesaro, AstraZeneca, Pfizer, Clovis; Speaker Bureau / Expert testimony: Roche, Novartis, Tesaro, AstraZeneca, Pfizer, Clovis; Travel / Accommodation / Expenses: Roche, Novartis, Tesaro, Pfizer. S. Wang: Full / Part-time employment: Tesaro. All other authors have declared no conflicts of interest.

Objectives Phosphatidylinositol 3-kinase catalytic subunit alpha (PIK3CA) is commonly altered in many human tumors, leading to the activation of p110α enzymatic activity that stimulates growth factor-independent cell growth. PIK3CA alterations such as mutation, gene amplification and overexpression are common in head and neck squamous cell carcinoma (HNSCC) and. We aim to explore how these alterations and clinical outcome are associated, as well as the molecular mechanisms involved. Material and methods Mutation and copy-number variation in PIK3CA, and whole-genome expression profiles, were analyzed in primary HNSCC tumors from The Cancer Genome Atlas (TCGA) cohort (n = 243). The results were validated in an independent cohort form the University Hospital of A Coruna (UHAC, n = 62). Expression of the PIK3CA gene protein product (PI3K p110α) and nuclear YAP were assessed in tissue microarrays in a cohort from the University Hospital 12 de Octubre (UH12O, n = 91). Results Only high expression of the PIK3CA gene was associated with poor clinical outcome. The study of gene expression, transcription factor and protein signatures suggested that the activation of the Hippo-YAP pathway, involved in organ size, stem cell maintenance and tumorigenesis, could underlie tumor progression in PI3KCA overexpressing tumors. Tissue arrays showed that PI3K p110α levels correlated with YAP nuclear localization in HNSCC tumors. Conclusions High expression of PIK3CA in HNSCC primary tumors identifies patients at high risk for recurrence. In these tumors, progression could rely on the Hippo-YAP pathway instead of the canonical Akt/mTOR pathway. This observation could have important implications in the therapeutic options for patients.

This is an open-access article distributed under the terms of the Creative Commons Attribution License.-- et al., The TP63 gene codes for two major isoform types, TAp63 and ΔNp63, with probable opposite roles in tumorigenesis. The ΔNp63α protein is frequently amplified and overexpressed in different epithelial tumors. Accordingly, it has been considered a potential oncogene. Nonetheless, a possible metastatic suppressor activity has also been suggested based on the experimental observation that its expression is reduced or even absent in advanced invasive tumors. Such metastatic suppressor activities are often related to tumors bearing point mutated TP53 gene. However, its potential roles in TP53-deficient tumors are poorly characterized. Here we show that in spontaneous tumors, induced by the epidermal-specific Trp53 ablation, the reduction of ΔNp63 expression is an early event, whereas it is re-expressed in the lung metastatic lesions. Using knock down and ectopic expression approaches, we show that ΔNp63 expression opposes the epithelial-mesenchymal transition and reduces the metastatic potential of the cells. This process occurs through the modulation of ΔNp63-dependent downstream targets (including transcription factors and microRNAs) likely to play metastatic roles. Further, ΔNp63 also favors the expression of factors involved in iPS reprogramming, thus suggesting that it can also modulate specific stem cell traits in mouse epidermal tumor cells. Overall, our data assign antimetastatic roles to ΔNp63 in the context of p53 deficiency and epidermis., The study was funded by the following: MINECO grant SAF2012–34378; Comunidad Autónoma de Madrid grant S2010/BMD-2470 (Oncocycle Program); AES grants ISCIII-RETIC RD06/0020/0029 and RD12/0036/0009 to J.M. Paramio. Grants AP99782012 from MMA Foundation to M. Dueñas. AES grant ISCIIIFIS PI12/01959 to M. Santos.

Traditionally, bladder cancer has been classified based on histology features. Recently, some works have proposed a molecular classification of invasive bladder tumors. To determine whether proteomics can define molecular subtypes of muscle invasive urothelial cancer (MIUC) and allow evaluating the status of biological processes and its clinical value. 58 MIUC patients who underwent curative surgical resection at our institution between 2006 and 2012 were included. Proteome was evaluated by high-throughput proteomics in routinely archive FFPE tumor tissue. New molecular subgroups were defined. Functional structure and individual proteins prognostic value were evaluated and correlated with clinicopathologic parameters. 1,453 proteins were quantified, leading to two MIUC molecular subgroups. A protein-based functional structure was defined, including several nodes with specific biological activity. The functional structure showed differences between subtypes in metabolism, focal adhesion, RNA and splicing nodes. Focal adhesion node has prognostic value in the whole population. A 6-protein prognostic signature, associated with higher risk of relapse (5 year DFS 70% versus 20%) was defined. Additionally, we identified two MIUC subtypes groups. Prognostic information provided by pathologic characteristics is not enough to understand MIUC behavior. Proteomics analysis may enhance our understanding of prognostic and classification. These findings can lead to improving diagnosis and treatment selection in these patients.

[Abstract] Background: Several potential predictive markers of efficacy of targeted agents in patients with metastatic renal cell carcinoma (mRCC) have been identified. Interindividual heterogeneity warrants further investigation. Patients and methods: Multicenter, observational, retrospective study in patients with clear-cell mRCC treated with sunitinib. Patients were classified in two groups: long-term responders (LR) (progression-free survival (PFS)≥22 months and at least stable disease), and primary refractory (PR) (progressive disease within 3-months of sunitinib onset). Objectives were to compare baseline clinical factors in both populations and to correlate tumor expression of selected signaling pathways components with sunitinib PFS. Results: 123 patients were analyzed (97 LR, 26 PR). In the LR cohort, overall response rate was 79% and median duration of best response was 30 months. Median PFS and overall survival were 43.2 (95% confidence intervals[CI]:37.2-49.3) and 63.5 months (95%CI:55.1-71.9), respectively. At baseline PR patients had a significantly lower proportion of nephrectomies, higher lactate dehydrogenase and platelets levels, lower hemoglobin, shorter time to and higher presence of metastases, and increased Fuhrman grade. Higher levels of HEYL, HEY and HES1 were observed in LR, although only HEYL discriminated populations significantly (AUC[ROC]=0.704; cut-off=34.85). Increased levels of hsa-miR-27b, hsa-miR-23b and hsa-miR-628-5p were also associated with prolonged survival. No statistical significant associations between hsa-miR-23b or hsa-miR-27b and the expression of c-Met were found. Conclusions: Certain mRCC patients treated with sunitinib achieve extremely long-term responses. Favorable baseline hematology values and longer time to metastasis may predict longer PFS. HEYL, hsa-miR-27b, hsa-miR-23b and hsa-miR-628-5p could be potentially used as biomarkers of sunitinib response. PPfizer; SOGUG-2011-05 Ministerio de Economía, Industria y Competitividad; SAF2015-66015-R Ministerio de Economía, Industria y Competitividad; ISCIII-RETIC RD12/0036/0009 Ministerio de Economía, Industria y Competitividad; PIE 15/00076

Purpose: Bladder cancer is a current clinical and social problem. At diagnosis, most patients present with nonmuscle-invasive tumors, characterized by a high recurrence rate, which could progress to muscle-invasive disease and metastasis. Bone morphogenetic protein (BMP)–dependent signaling arising from stromal bladder tissue mediates urothelial homeostasis by promoting urothelial cell differentiation. However, the possible role of BMP ligands in bladder cancer is still unclear. Experimental Design: Tumor and normal tissue from 68 patients with urothelial cancer were prospectively collected and analyzed for expression of BMP and macrophage markers. The mechanism of action was assessed in vitro by experiments with bladder cancer cell lines and peripheral blood monocyte–derived macrophages. Results: We observed BMP4 expression is associated and favored type II macrophage differentiation. In vitro experiments showed that both recombinant BMP4 and BMP4-containing conditioned media from bladder cancer cell lines favored monocyte/macrophage polarization toward M2 phenotype macrophages, as shown by the expression and secretion of IL10. Using a series of human bladder cancer patient samples, we also observed increased expression of BMP4 in advanced and undifferentiated tumors in close correlation with epithelial–mesenchymal transition (EMT). However, the p-Smad 1,5,8 staining in tumors showing EMT signs was reduced, due to the increased miR-21 expression leading to reduced BMPR2 expression. Conclusions: These findings suggest that BMP4 secretion by bladder cancer cells provides the M2 signal necessary for a protumoral immune environment. In addition, the repression of BMPR2 by miR-21 makes the tumor cells refractory to the prodifferentiating actions mediated by BMP ligands, favoring tumor growth. Clin Cancer Res; 23(23); 7388–99. ©2017 AACR.

BackgroundLong non-coding RNAs (lncRNAs) have emerged as key players in a remarkably variety of biological processes and pathologic conditions, including cancer. Next-generation sequencing technologies and bioinformatics procedures predict the existence of tens of thousands of lncRNAs, from which we know the functions of only a handful of them, and very little is known in cancer types such as head and neck squamous cell carcinomas (HNSCCs).ResultsHere, we use RNA-seq expression data from The Cancer Genome Atlas (TCGA) and various statistic and software tools in order to get insight about the lncRNome in HNSCC. Based on lncRNAs expression across 426 samples, we discover five distinct tumor clusters that we compare with reported clusters based on various genomic/genetic features. Results demonstrate significant associations between lncRNA-based clustering and DNA-methylation, TP53 mutation, and human papillomavirus infection. Using “guilt by association” procedures, we infer the possible biological functions of representative lncRNAs of each cluster. Furthermore, we found that lncRNA clustering is correlated with some important clinical and pathologic features, including patient survival after treatment, tumor grade or sub-anatomical location.ConclusionsWe present a landscape of lncRNAs in HNSCC, and provide associations with important genotypic and phenotypic features that may help to understand the disease.

IKKβ (encoded by

// Cristina Segovia 1, 2, 3, * , Monica Martinez-Fernandez 1, 2, 3, * , Marta Duenas 1, 2, 3, * , Carolina Rubio 2, 3 , Fernando F. Lopez-Calderon 2 , Clotilde Costa 1, 4 , Cristina Saiz-Ladera 1, 5 , Maria Fernandez-Grajera 1 , Jose Duarte 2, 3 , Huberto Garcia Munoz 6 , Federico de la Rosa 2, 3 , Felipe Villacampa 2, 3 , Daniel Castellano 2, 3 , Jesus M. Paramio 1, 2, 3 1 Unidad de Oncologia Molecular, CIEMAT (ed70A), Madrid, Spain 2 Grupo de Oncologia celular y Molecular, Hospital Universitario 12 de Octubre, Madrid, Spain 3 Centro de Investigacion Biomedica en Red de Cancer (CIBER ONC), Spain 4 Unidad Mixta Roche-CHUS, Hospital Universitario de Santiago de Compostela, Travesia de Choupana, s/n, Santiago de Compostela, A Coruna, Spain 5 Departamento de Bioquimica y Biologia Molecular I, Facultad de Biologia, Universidad Complutense, Madrid, Spain 6 Servicio de Anatomia Patologica, Hospital Universitario 12 de Octubre, Instituto de Investigacion 12 de Octubre i+12, UCM, Av Cordoba s/n, Madrid, Spain * These authors have contributed equally to this work Correspondence to: Jesus M. Paramio, email: jesusm.paramio@ciemat.es Keywords: bladder cancer, PIK3CA, genomics, Ezh2, recurrence progression Received: July 20, 2016 Accepted: December 12, 2016 Published: January 02, 2017 ABSTRACT The high rates of tumor recurrence and progression represent a major clinical problem in non-muscle invasive bladder cancer. Previous data showed that EZH2-dependent signaling mediates these processes, whereas the frequent alterations of PIK3CA gene (copy gains and mutations) are predictive of reduced recurrence. Here we show, using clinical samples and bladder cancer cell lines, a functional interaction between EZH2- and PIK3CA-dependent signaling pathways. PIK3CA alterations mediated, on the one hand, the increased expression of two miRNAs, miR-101 and miR-138, which posttranscriptionally downregulate EZH2 expression. On the other hand, PIK3CA alterations facilitate the activation of Akt which phosphorylates EZH2 on Ser21, precluding the trimethylation of histone H3 in K27. Remarkably the increased expression of miR101 or miR138 and the expression of Ser21-phosphorylated EZH2 are good prognostic factors regarding non-muscle invasive bladder cancer recurrence and progression. Collectively, this study provides molecular evidences indicating that the gene expression rewiring occurring in primary bladder tumors, associated with increased EZH2 expression and activity and mediating the increased recurrence and progression risk, are prevented by PIK3CA-dependent signaling. This molecular process may have deep implications in the management of bladder cancer patients and in the design of novel molecularly targeted therapeutic approaches.

Hair follicle stem cells (HF-SCs) alternate between periods of quiescence and proliferation, to finally differentiate into all the cell types that constitute the hair follicle. Also, they have been recently identified as cells of origin in skin cancer. HF-SCs localize in a precise region of the hair follicle, the bulge, and molecular markers for this population have been established. Thus, HF-SCs are good model to study the potential role of oncogenic activations on SC physiology. Expression of a permanently active form of Akt (myrAkt) in basal cells leads to Akt hyperactivation specifically in the CD34+Itga6H population. This activation causes bulge stem cells to exit from quiescence increasing their response to proliferative stimuli and affecting some functions such as cell migration. HF-SC identity upon Akt activation is preserved; in this sense, increased proliferation does not result in stem cell exhaustion with age suggesting that Akt activation does not affect self-renewal an important aspect for normal tissue maintenance and cancer development. Genome-wide transcriptome analysis of HF-SC isolated from myrAkt and wild-type epidermis underscores changes in metabolic pathways characteristic of cancer cells. These differences manifest during a two-step carcinogenesis protocol in which Akt activation in HF-SCs results in increased tumor development and malignant transformation. Stem Cells 2014;32:1917–1928

e16034 Background: There are limited treatment options for mUC after platinum-based chemotherapy failure. Immune checkpoint inhibitors (ICI) have shown a durable benefit but only in a minority of patients (20-25%). Vinflunine remains as a therapeutic option without validated biomarkers. In this study, we sought to analyze the molecular determinants of vinflunine response in mUC. Methods: mUC patients from 4 University Hospitals in Spain who received second-line vinflunine after platinum-based chemotherapy were classified in non-responders (NR: progressive disease ≤3 months; N = 10) or responders (R: response ≥ 6 months, N = 14). Targeted- sequencing of 275 cancer-related genes and a PanCancer Immune Profiling Panel were performed on pre-treatment tumors. Selected genes were evaluated by RT-qPCR and protein expression was detected by immunohistochemistry. Results: The most common alteration, TP53 mutations, had a similar frequency in R (7/14, 50%) and NR (4/10, 40%). Mutations in 5 genes: ERBB3 (4/14; 28,6%), KTM2C (4/14; 28,6%), PI3KCA (4/14; 28,6%), ARID2 (3/14; 21,4%) and FGFR3 (3/14; 21,4%) were identified only in R. Mutations in ERBB4 (3/10, 33,3%) and BCOR (2/10, 20%) were identified only in NR. Estimated TMBs were not significantly different among the R (13 per Mb) and NR (9 per Mb) samples. According to gene expression profiling, NR had high cytotoxic cells infiltrate and T cells as well as high counts of TILs compared to R. In addition, expression of IDO, MAGE A4, and SOCS1, that has been associated with response to ICIs, were down-regulated in R compared with NR. Conclusions: Gene profiling showed that low-expression levels of immune-related genes are significantly associated with clinical benefit from vinflunine. Validation and complementary studies are ongoing in patients treated with ICIs.

449 Background: Immune checkpoint inhibitors (ICIs) have demonstrated clinical benefit in advanced urothelial cancer (UC) patients. An alert was issued about a decrease in survival for bladder cancer patients with PD-L1-low status receiving immunotherapy versus chemotherapy as first-line therapy. We studied a small series of UC patients treated with first-line PD-1 checkpoint inhibition in order to analyze their characteristics and patterns of response to therapy. Methods: Eleven UC samples were obtained from patients before undergoing therapy with ICIs. Patients were classified according to their benefit from therapy in responders (n=5) and non-responders (n=6). Genomic and immunohistochemistry analyses were performed. Results: Both luminal and basal UC subtypes showed benefit from ICIs. Tumors from non-responders showed increased mutations in chromatin remodelling genes and the amplification of 3q26-28 region. Transcriptome analyses showed that tumors from responders displayed a significant enrichment of genes associated with interferon γ and α response, TNFα via NFκB, genes upregulated by MYC or E2F1, genes involved in G2/M checkpoint and epithelial-mesenchymal transition compared to non-responders. Specific immune cell subsets were present in the tumor microenvironment of tumors from responders and non-responders. Immunohistochemistry showed that none of the immune cell markers analyzed individually was sufficient to discriminate between responders and non-responders. However, the increase in FOXP-3, PD-L1, PD-1, CD8, β2 microglobulin and CD68 and the decrease in CD4 and CD163 cells identified UC patients that responded to ICIs. Conclusions: Our findings confirm that the evaluation of pre-treatment UC tumor samples provides valuable information that could influence treatment decisions. Despite the clinical benefit of PD-1/PD-L1 inhibition in UC, only a fraction of patients benefit from therapy. Our data suggest that responders and non-responders display diverse genomic and transcriptome changes as well as specific immune cell subsets in the tumor microenvironment that can be identified by conventional IHC staining.

TPS501 Background: Niraparib (N) is an orally selective poly(ADP-ribose) polymerase (PARP)-1/-2 inhibitor approved for maintenance treatment of patients (pt) with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer after complete or partial response to platinum-based chemotherapy (CT). Cabozantinib (C) is a tyrosine kinase (TK) inhibitor with activity against TKs including VEGFR2, MET and AXL, approved on kidney cancer pt after TK failure, that has demonstrated clinical activity in heavily pretreated, advanced UC pt. c-Met receptor TK is activated in urothelial carcinoma (UC) cells. c-Met activity can decrease response to PARP inhibitors, whereas treatment with c-Met inhibitors renders cells more sensitive to PARP inhibition. UC pt with tumors overexpressing c-Met may benefit from the combination of c-Met and PARP inhibitors. This multicenter, open-label phase (ph) I-II study is to explore the maximum-tolerated dose (MTD) of N + C combination in pt with advanced genitourinary malignancies (UC and kidney cancer) follow by a preliminary efficacy of the combination in advanced UC. Methods: Eligible pt have confirmed histopathology of UC or clear cell renal cell carcinoma, advanced or metastatic disease, age ≥18 years, ECOG PS ≤1, progressive disease after platinum-based CT, measurable lesions, no prior therapy with PARP or c-Met inhibitors and adequate bone marrow, liver and renal functions. The ph I portion is enrolling ≈24 pt to identify the MTD proposed to use in a ph II (RP2D). Pt will receive N and C p.o. once daily in 28-day cycles: Dose level 1 (DL1) N/C 100/20 mg; DL2 200/20 mg; DL3 200/40 mg; DL4 200/60 mg. Pt will be accrued to each dose level in cohorts of 6 pt until the MTD is achieved (the highest dose at which ≤1 out of 6 pt experience a dose-limiting toxicity [DLT]). DLT will be evaluated during the first 2 cycles. The ph 2 portion will enroll 51 UC pt to receive the RP2D. Tumor response will be assessed per RECIST v1.1. Endpoints of the ph 2 are 6-month PFS (primary), overall response rate, disease control rate, duration of response, PFS and OS. Tissue and plasma sample will be collected for translational study. Clinical trial information: NCT03425201.

Bladder cancer (BC) is the fifth most common cancer in the world, being the non-muscle invasive tumors (NMIBC) the most frequent. NMIBC shows a very high frequency of recurrence and, in certain cases, tumor progression. The phosphatidylinositol 3-kinase (PI3K) pathway, which controls cell growth, tumorigenesis, cell invasion and drug response, is frequently activated in numerous human cancers, including BC, in part through alterations of PIK3CA gene. However, the significance of PIK3CA gene alterations with respect to clinicopathological characteristics, and in particular tumor recurrence and progression, remains elusive. Here, we analyzed the presence of mutations in FGFR3 and PIK3CA genes and copy number alterations of PIK3CA gene in bladder tumor and their correspondent paired normal samples from 87 patients. We observed an extremely high frequency of PIK3CA gene alterations (mutations, copy gains, or both) in tumor samples, affecting primarily T1 and T2 tumors. A significant number of normal tissues also showed mutations and copy gains, being coincident with those found in the corresponding tumor sample. In low-grade tumors PIK3CA mutations associated with FGFR3 mutations. Alterations in PIK3CA gene resulted in increased Akt activity in tumors. Interestingly, the presence of PIK3CA gene alterations, and in particular gene mutations, is significantly associated with reduced recurrence of NMIBC patients. Importantly, the presence of FGFR3 mutations may influence the clinical outcome of patients bearing alterations in PIK3CA gene, and increased recurrence was associated to FGFR3 mutated, PIK3CA wt tumors. These findings may have high relevance in terms of using PI3K-targeted therapies for BC treatment.

Squamous cell carcinoma (SCC) or epidermoid cancer is a frequent and aggressive malignancy. However in apparent paradox it retains the squamous differentiation phenotype except for very dysplastic lesions. We have shown that cell cycle stress in normal epidermal keratinocytes triggers a squamous differentiation response involving irreversible mitosis block and polyploidisation. Here we show that cutaneous SCC cells conserve a partial squamous DNA damage-induced differentiation response that allows them to overcome the cell division block. The capacity to divide in spite of drug-induced mitotic stress and DNA damage made well-differentiated SCC cells more genomically instable and more malignant in vivo. Consistently, in a series of human biopsies, non-metastatic SCCs displayed a higher degree of chromosomal alterations and higher expression of the S phase regulator Cyclin E and the DNA damage signal γH2AX than the less aggressive, non-squamous, basal cell carcinomas. However, metastatic SCCs lost the γH2AX signal and Cyclin E, or accumulated cytoplasmic Cyclin E. Conversely, inhibition of endogenous Cyclin E in well-differentiated SCC cells interfered with the squamous phenotype. The results suggest a dual role of cell cycle stress-induced differentiation in squamous cancer: the resulting mitotic blocks would impose, when irreversible, a proliferative barrier, when reversible, a source of genomic instability, thus contributing to malignancy. AG is grateful to Jean-Jeaques Guilhou, Jean-Claude Rossi and the INSERM for professional support and to Renata Polakowska for the generous gift of precious BCCP cell line. We thank Lucía Barbier, Tania Lobato, Evelyn Andrades, Alicia Noriega and María Aramburu for technical assistance and Natalia Sanz for critical reading of the MS. To AG: National grants from Instituto de Salud Carlos III, Fondo de Investigación Sanitaria (ISCIII-FIS/FEDER, Spain): PI08/0890, PI11/02070, PI14/00900; Ligue Nationale Contre la Cancer (La Ligue; France). To AT: ISCIII-FIS PI10/00785. To JP: MINECO grant SAF2015-66015-R; AES grant ISCIII-RETIC RD12/0036/0009. VC was funded by a fellowship from La Ligue (France), PA by IDIVAL (Spain), RM and IdP by AG lab and ISCIII-FIS-FEDER PI11/02070 (Spain).

// Josefa P. Alameda 1, 2 , Miriam Gaspar 1 , Angel Ramirez 1, 2 , Manuel Navarro 1, 2 , Angustias Page 1, 2 , Cristian Suarez-Cabrera 1, 2 , M. Guadalupe Fernandez 3 , Jose R. Merida 3 , Jesus M. Paramio 1, 2 , Rosa A. Garcia-Fernandez 4 , M. Jesus Fernandez-Acenero 5 , M. Llanos Casanova 1, 2 1 Molecular Oncology Unit, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), 28040 Madrid, Spain 2 Molecular Oncology, Institute of Biomedical Investigation University Hospital “12 de Octubre”, 28041 Madrid, Spain 3 Department of Human Anatomy and Embriology, Facultad de Medicina, UCM, 28040 Madrid, Spain 4 Department of Animal Medicine and Surgery, Facultad de Veterinaria, UCM, 28040 Madrid, Spain 5 Department of Pathology, Hospital Clinico San Carlos, 28040 Madrid, Spain Correspondence to: M. Llanos Casanova, email: llanos.casanova@ciemat.es Keywords: nuclear IKKα, cytoplasmic IKKα, skin cancer, Maspin, c-Myc Received: November 06, 2015 Accepted: March 28, 2016 Published: April 18, 2016 SUMMARY Nonmelanoma skin cancers (NMSC) are the most common human malignancies. IKKα is an essential protein for skin development and is also involved in the genesis and progression of NMSC, through mechanisms not fully understood. While different studies show that IKKα protects against skin cancer, others indicate that it promotes NMSC. To resolve this controversy we have generated two models of transgenic mice expressing the IKKα protein in the nucleus (N-IKKα mice) or the cytoplasm (C-IKKα mice) of keratinocytes. Chemical skin carcinogenesis experiments show that tumors developed by both types of transgenic mice exhibit histological and molecular characteristics that make them more prone to progression and invasion than those developed by Control mice. However, the mechanisms through which IKKα promotes skin tumors are different depending on its subcellular localization; while IKKα of cytoplasmic localization increases EGFR, MMP-9 and VEGF-A activities in tumors, nuclear IKKα causes tumor progression through regulation of c-Myc, Maspin and Integrin-α6 expression. Additionally, we have found that N-IKKα skin tumors mimic the characteristics associated to aggressive human skin tumors with high risk to metastasize. Our results show that IKKα has different non-overlapping roles in the nucleus or cytoplasm of keratinocytes, and provide new targets for intervention in human NMSC progression.

p53 is a protein that causes cell cycle arrest, apoptosis or senescence, being crucial in the process of tumor suppression in several cell types. Different in vitro and animal models have been designed for the study of p53 role in skin cancer. These models have revealed opposing results, as in some experimental settings it appears that p53 protects against skin cancer, but in others, the opposite conclusion emerges. We have generated cohorts of mice with efficient p53 deletion restricted to stratified epithelia and control littermates expressing wild type p53 and studied their sensitivity to both chemically-induced and spontaneous tumoral transformation, as well as the tumor types originated in each experimental group. Our results indicate that the absence of p53 in stratified epithelia leads to the appearance, in two-stage skin carcinogenesis experiments, of a higher number of tumors that grow faster and become malignant more frequently than tumors arisen in mice with wild type p53 genotype. In addition, the histological diversity of the tumor type is greater in mice with epidermal p53 loss, indicating the tumor suppressive role of p53 in different epidermal cell types. Aging mice with p53 inactivation in stratified epithelia developed spontaneous carcinomas in skin and other epithelia. Overall, these results highlight the truly protective nature of p53 functions in the development of cancer in skin and in other stratified epithelia.

Cyclin-dependent kinase (Cdk)7, the catalytic subunit of the Cdk-activating kinase (CAK) complex has been implicated in the control of cell cycle progression and of RNA polymerase II (RNA pol II)-mediated transcription. Genetic inactivation of the Cdk7 locus revealed that whereas Cdk7 is completely dispensable for global transcription, is essential for the cell cycle via phosphorylation of Cdk1 and Cdk2. In vivo, Cdk7 is also indispensable for cell proliferation except during the initial stages of embryonic development. Interestingly, widespread elimination of Cdk7 in adult tissues with low proliferative indexes had no phenotypic consequences. However, ablation of conditional Cdk7 alleles in tissues with elevated cellular turnover led to the efficient repopulation of these tissues with Cdk7-expressing cells most likely derived from adult stem cells that may have escaped the inactivation of their targeted Cdk7 alleles. This process, a physiological attempt to maintain tissue homeostasis, led to the attrition of adult stem cell pools and to the appearance of age-related phenotypes, including telomere shortening and early death.

The cyclin-cdk (cyclin-dependent kinase) inhibitor p27Kip1 (p27) has a crucial negative role on cell cycle progression. In addition to its classical role as a cyclin-cdk inhibitor, it also performs cyclin-cdk-independent functions as the regulation of cytoskeleton rearrangements and cell motility. p27 deficiency has been associated with tumor aggressiveness and poor clinical outcome, although the mechanisms underlying this participation still remain elusive. We report here a new cellular function of p27 as a transcriptional regulator in association with p130/E2F4 complexes that could be relevant for tumorigenesis. We observed that p27 associates with specific promoters of genes involved in important cellular functions as processing and splicing of RNA, mitochondrial organization and respiration, translation and cell cycle. On these promoters p27 co-localizes with p130, E2F4 and co-repressors as histone deacetylases (HDACs) and mSIN3A. p27 co-immunoprecipitates with these proteins and by affinity chromatography, we demonstrated a direct interaction of p27 with p130 and E2F4 through its carboxyl-half. We have also shown that p130 recruits p27 on the promoters, and there p27 is needed for the subsequent recruitment of HDACs and mSIN3A. Expression microarrays and luciferase assays revealed that p27 behaves as transcriptional repressor of these p27-target genes (p27-TGs). Finally, in human tumors, we established a correlation with overexpression of p27-TGs and poor survival. Thus, this new function of p27 as a transcriptional repressor could have a role in the major aggressiveness of tumors with low levels of p27.

We have analyzed the role of the thyroid hormone receptors (TRs) in epidermal homeostasis. Reduced keratinocyte proliferation is found in interfollicular epidermis of mice lacking the thyroid hormone binding isoforms TRα1 and TRβ (KO mice). Similar results were obtained in hypothyroid animals, showing the important role of the liganded TRs in epidermal proliferation. In addition, KO and hypothyroid animals display decreased hyperplasia in response to 12-O-tetradecanolyphorbol-13-acetate. Both receptor isoforms play overlapping functional roles in the skin because mice lacking individually TRα1 or TRβ also present a proliferative defect but not as marked as that found in double KO mice. Defective proliferation in KO mice is associated with reduction of cyclin D1 expression and up-regulation of the cyclin-dependent kinase inhibitors p19 and p27. Paradoxically, ERK and AKT activity and expression of downstream targets, such as AP-1 components, are increased in KO mice. Increased p65/NF-κB and STAT3 phosphorylation and, as a consequence, augmented expression of chemokines and proinflammatory cytokines is also found in these animals. These results show that thyroid hormones and their receptors are important mediators of skin proliferation and demonstrate that TRs act as endogenous inhibitors of skin inflammation, most likely due to interference with AP-1, NF-κB, and STAT3 activation., This work was supported by Ministerio de Ciencia e Innovación Grants BFU2007-62402 and SAF2008-00121, Fondo de Investigaciones Sanitarias Grants RD06/0020/0036 and RD06/0020/0029, and European CRESCENDO Grant FP-018652.

Tumor cells arise as a consequence of the acquisition of defined properties, due to gene alterations, which control the equilibrium of cell proliferation and survival. Most targeted therapeutic approaches are focused on the inhibition of those alterations leading to gain of function. This situation is different when these acquired properties are used to loss of function, which usually affect tumor suppressor genes. This accounts for a limited use of these alterations as therapeutic targets. However, this potential problem can be overcome by the use of synthetic lethality approaches (see below).

The infection by mucosal human papillomavirus (HPV) is causally associated with tumor development in cervix and oropharynx. The mechanisms responsible for this oncogenic potential are mainly due to the product activities of two early viral oncogenes: E6 and E7. Although a large number of cellular targets have been described for both oncoproteins, the interaction with tumor suppressors p53 and retinoblastoma protein (pRb) emerged as the key functional activities. E6 degrades tumor suppressor p53, thus inhibiting p53-dependent functions, whereas E7 binds and degrades pRb, allowing the transcription of E2F-dependent genes. Since these two tumor suppressors exert their actions through transcriptional modulation, functional genomics has provided a large body of data that reflects the altered gene expression of HPVinfected cells or tissues. Here we will review the similarities and differences of these findings, and we also compare them with those obtained with transgenic mouse models bearing the deletion of some of the viral oncogene targets. The comparative analysis supports molecular evidences about the role of oncogenes E6 and E7 in the interference with the mentioned cellular functions, and also suggests that the mentioned transgenic mice can be used as models for HPV-associated diseases such as human cervical, oropharynx, and skin carcinomas.

Head and neck squamous cell carcinoma (HNSCC) is a common human neoplasia with poor prognosis and survival that frequently displays Akt overactivation. Here we show that mice displaying constitutive Akt activity (myrAkt) in combination with Trp53 loss in stratified epithelia develop oral cavity tumors that phenocopy human HNSCC. The myrAkt mice develop oral lesions, making it a possible model of human oral dysplasia. The malignant conversion of these lesions, which is hampered due to the induction of premature senescence, is achieved by the subsequent ablation of Trp53 gene in the same cells in vivo. Importantly, mouse oral tumors can be followed by in vivo imaging, show metastatic spreading to regional lymph nodes, and display activation of nuclear factor-κB and signal transducer and activator of transcription-3 pathways and decreased transforming growth factor-β type II receptor expression, thus resembling human counterparts. In addition, malignant conversion is associated with increased number of putative tumor stem cells. These data identify activation of Akt and p53 loss as a major mechanism of oral tumorigenesis in vivo and suggest that blocking these signaling pathways could have therapeutic implications for the management of HNSCC. [Cancer Res 2009;69(3):1099–108]

The sequentiation of the human genome, together with the development of high throughput technologies, particularly gene-expression profiling, is giving us the opportunity to describe biological features in a quantitative manner. Here we review the use of global gene expression analyses in cancer research. Microarray analyses of tumor samples have allowed researchers the development of profiles that can distinguish, identify and classify discrete subsets of disease, predict the disease outcome, or the response to therapy. Profiling of experimental models with activation of certain oncogenic pathways could also be used to ascertain the molecular events involved in the establishment and development of tumors and, consequently, these models could be validated as tools for preclinical therapy. Furthermore, the detailed analysis of gene expression deregulation after response to the therapies in such models would allow us to predict the response to specific drugs, and to target the therapies to patients in search for individualized management of the disease. © 2008 Wiley-Liss, Inc.

Functional inactivation of the pRb-dependent pathway is a general feature of human cancer. However, only a reduced spectrum of tumors displays inactivation of the Rb gene. This can be attributed, at least partially, to the possible overlapping functions carried out by the related retinoblastoma family members p107 and p130. We observed that loss of pRb in epidermis, using the Cre/LoxP technology, results in proliferation and differentiation defects. These alterations are partially compensated by the elevation in the levels of p107. Moreover, epidermis lacking pRb and p107, but not pRb alone, develops spontaneous tumors, and double deficient primary keratinocytes are highly susceptible to Ha-ras-induced transformation. Two-stage chemical carcinogenesis experiments in mice lacking pRb in epidermis revealed a reduced susceptibility in papilloma formation and an increase in the malignant conversion. We have now explored whether the loss of one p107 allele, inducing a decrease in the levels of p107 up to normal levels could restore the susceptibility of pRb-deficient skin to two-stage protocol. We observed partial restoration in the incidence, number, and size of tumors. However, there is no increased malignancy despite sustained p53 activation. We also observed a partial reduction in the levels of proapoptotic proteins in benign papillomas. These data confirm our previous suggestions on the role of p107 as a tumor suppressor in epidermis in the absence of pRb. © 2008 Wiley-Liss, Inc.

Aberrant activation of the Akt pathway has been implicated in several human pathologies including cancer. However, current knowledge on the involvement of Akt signaling in development is limited. Previous data have suggested that Akt-mediated signaling may be an essential mediator of epidermal homeostasis through cell autonomous and noncell autonomous mechanisms. Here we report the developmental consequences of deregulated Akt activity in the basal layer of stratified epithelia, mediated by the expression of a constitutively active Akt1 (myrAkt) in transgenic mice. Contrary to mice overexpressing wild-type Akt1 (Aktwt), these myrAkt mice display, in a dose-dependent manner, altered development of ectodermally derived organs such as hair, teeth, nails, and epidermal glands. To identify the possible molecular mechanisms underlying these alterations, gene profiling approaches were used. We demonstrate that constitutive Akt activity disturbs the bone morphogenetic protein-dependent signaling pathway. In addition, these mice also display alterations in adult epidermal stem cells. Collectively, we show that epithelial tissue development and homeostasis is dependent on proper regulation of Akt expression and activity.

The specific deletion of Rb gene in epidermis leads to altered proliferation and differentiation, but not to the development of spontaneous tumors. Our previous data have demonstrated the existence of a functional compensation of Rb loss by Rbl1 (p107) in as the phenotypic differences with respect to controls are intensified. However, the possible evolution of this aggravated phenotype, in particular in relationship with tumorigenesis, has not been evaluated due to the premature death of the double deficient mice. We have now investigated whether p107 can also act as a tumor suppressor in pRb-deficient epidermis using different experimental approaches. We found spontaneous tumor development in doubly-deficient skin grafts. Moreover, Rb-deficient keratinocytes are susceptible to Ha-ras-induced transformation, and this susceptibility is enhanced by p107 loss. Further functional analyses, including microarray gene expression profiling, indicated that the loss of p107, in the absence of pRb, produces the reduction of p53-dependent pro-apoptotic signals. Overall, our data demonstrate that p107 behaves as a tumor suppressor in epidermis in the absence of pRb and suggest novel tumor-suppressive roles for p107 in the context of functional p53 and activated Ras. © 2007 Wiley-Liss, Inc., This work was partially supported by grants: SAF2002-01037 (MCYT), Oncocycle (CAM), ISCIII-RETIC RD06/0020 (MSC), SAF2005-00033 (MCYT) and Oncology Program from La Caixa Foundation to JMP. SR is recipient of a Juan de la Cierva Fellowship.

NANOG is a key pluripotency factor in embryonic stem cells that is frequently expressed in squamous cell carcinomas (SCCs). However, a direct link between NANOG and SCCs remains to be established. Here, we show that inducible overexpression of NANOG in mouse skin epithelia favours the malignant conversion of skin papillomas induced by chemical carcinogenesis, leading to increased SCC formation. Gene expression analyses in pre-malignant skin indicate that NANOG induces genes associated to epithelial-mesenchymal transition (EMT). Some of these genes are directly activated by NANOG, including EMT-associated genes Zeb1, Zeb2, Twist1, Prrx1 and miR-21. Finally, endogenous NANOG binds to the promoters of theses genes in human SCC cells and, moreover, NANOG induces EMT features in primary keratinocytes. These results provide in vivo evidence for the oncogenic role of NANOG in squamous cell carcinomas.