Correlation Between Endoglin and Malignant Phenotype in Human Melanoma Cells: Analysis of hsa-mir-214 and hsa-mir-370 in Cells and Their Extracellular Vesicles.

Endoglin (CD105) is an auxiliary receptor of transforming growth factor (TGF)-β family members that is expressed in human melanomas. It is heterogeneously expressed by primary and metastatic melanoma cells, and endoglin targeting as a therapeutic strategy for melanoma tumors is currently been explored. However, its involvement in tumor development and malignancy is not fully understood. Here, we find that endoglin expression correlates with malignancy of primary melanomas and cultured melanoma cell lines. Next, we have analyzed the effect of ectopic endoglin expression on two miRNAs (hsa-mir-214 and hsa-mir-370), both involved in melanoma tumor progression and endoglin regulation. We show that compared with control cells, overexpression of endoglin in the WM-164 melanoma cell line induces; (i) a significant increase of hsa-mir-214 levels in small extracellular vesicles (EVs) as well as an increased trend in cells; and (ii) significantly lower levels of hsa-mir-370 in the EVs fractions, whereas no significant differences were found in cells. As hsa-mir-214 and hsa-mir-370 are not just involved in melanoma tumor progression, but they can also target endoglin-expressing endothelial cells in the tumor vasculature, these results suggest a complex and differential regulatory mechanism involving the intracellular and extracellular signaling of hsa-mir-214 and hsa-mir-370 in melanoma development and progression.S

DEK expression in Merkel cell carcinoma and small cell carcinoma

Background The chromatin architectural factor DEK maps to chromosome 6p and is frequently overexpressed in several neoplasms, including small cell lung carcinoma, where it is associated with poor prognosis, tumor initiation activity and chemoresistance. DEK expression has not been studied in cutaneous Merkel cell carcinoma. Methods We applied a DEK monoclonal antibody to 15 cases of Merkel cell carcinoma and 12 cases of small cell carcinoma. DEK nuclear immunoreactivity was scored based on percentage (0, negative; 1+, 50%) and intensity (weak, moderate or strong). Results All 15 Merkel cell carcinoma cases (100%) showed diffuse (3+) nuclear positivity (14 strong, 1 weak). Six of 12 small cell carcinoma cases (50%) showed diffuse (3+) and strong nuclear positivity, while one case exhibited focal (1+) weak nuclear positivity. The remaining five cases were negative for DEK expression. Conclusions Our results suggest that DEK may be involved in the pathogenesis of Merkel cell carcinoma and therefore may provide therapeutic implications for Merkel cell carcinomas. In addition, the difference in DEK expression between Merkel cell carcinoma and small cell carcinoma suggests possible separate tumorigenesis pathways for the two tumors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92401/1/cup1941.pd

Intermittent Hypoxia Is Associated With High Hypoxia Inducible Factor-1α but Not High Vascular Endothelial Growth Factor Cell Expression in Tumors of Cutaneous Melanoma Patients

Epidemiological associations linking between obstructive sleep apnea and poorer solid malignant tumor outcomes have recently emerged. Putative pathways proposed to explain that these associations have included enhanced hypoxia inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF) cell expression in the tumor and altered immune functions via intermittent hypoxia (IH). Here, we examined relationships between HIF-1α and VEGF expression and nocturnal IH in cutaneous melanoma (CM) tumor samples. Prospectively recruited patients with CM tumor samples were included and underwent overnight polygraphy. General clinical features, apnea-hypopnea index (AHI), desaturation index (DI4%), and CM characteristics were recorded. Histochemical assessments of VEGF and HIF-1α were performed, and the percentage of positive cells (0, 75%) was blindly tabulated for VEGF expression, and as 0, 0-5.9, 6.0-10.0, >10.0% for HIF-1α expression, respectively. Cases with HIF-1α expression >6% (high expression) were compared with those 75% of cells was compared with those with <75%. 376 patients were included. High expression of VEGF and HIF-1α were seen in 88.8 and 4.2% of samples, respectively. High expression of VEGF was only associated with increasing age. However, high expression of HIF-1α was significantly associated with age, Breslow index, AHI, and DI4%. Logistic regression showed that DI4% [OR 1.03 (95% CI: 1.01-1.06)] and Breslow index [OR 1.28 (95% CI: 1.18-1.46)], but not AHI, remained independently associated with the presence of high HIF-1α expression. Thus, IH emerges as an independent risk factor for higher HIF-1α expression in CM tumors and is inferentially linked to worse clinical CM prognostic indicators.IA is supported by SEPAR (086/2014 and 595/2017). MM-G is supported by the Instituto de Salud Carlos III (PI16/01772) and cofinanced by the European Development Regional Find “A way to achieve Europe” (ERDF) and SEPAR (211/2012). ER-F is the recipient of a postdoctoral fellowship from “Fundación Científica de la Asociación Española Contra el Cáncer” and supported by FMM-2013/0075 of “Fundación Mutua Madrileña.” JR-P is supported by FIS 2014/1737 from the Spanish Ministry of Health. RF is supported in part by the Spanish Ministry of Economy and Competitiveness—Instituto de Salud Carlos III (FIS-PI14/00004); DG is supported by National Institutes of Health grant 1R01HL130984 and by the Herbert T. Abelson Chair in Pediatrics

p62/SQSTM1 Fuels Melanoma Progression by Opposing mRNA Decay of a Selective Set of Pro-metastatic Factors

Modulators of mRNA stability are not well understood in melanoma, an aggressive tumor with complex changes in the transcriptome. Here we report the ability of p62/SQSTM1 to extend mRNA half-life of a spectrum of pro-metastatic factors. These include FERMT2 and other transcripts with no previous links to melanoma. Transcriptomic, proteomic, and interactomic analyses, combined with validation in clinical biopsies and mouse models, identified a selected set of RNA-binding proteins (RBPs) recruited by p62, with IGF2BP1 as a key partner. This p62-RBP interaction distinguishes melanoma from other tumors where p62 controls autophagy or oxidative stress. The relevance of these data is emphasized by follow-up analyses of patient prognosis revealing p62 and FERMT2 as adverse determinants of disease-free survival.M.S.S. is funded by grants from the Spanish Ministry of Economy and Innovation (SAF2014-56868-R; SAF2017-89533-R), the Asociación Española Contra el Cáncer (AECC), TV’13-20131430 (Marato de TV3), the Worldwide Cancer Research, an Established Investigator Award by the Melanoma Research Alliance (MRA), and a L'Oreal-Paris USA-MRA Team Science Award for Women in Scientific Research. M.S.S. also acknowledges a donation from “Fundación Causa Alexandra”, Spain. P.K. was a recipient of a predoctoral fellowship from Fundación La Caixa. E.R.-F. was funded by Fundación Mutua Madrileña (FMM-2013) and was a recipient of a fellowship from ‘‘Fundación Científica de la Asociación Española Contra el Cáncer”. The CNIO Proteomics Unit belongs to ProteoRed, PRB2-ISCIII, supported by grant PT13/0001. J.M. is also supported by Ramon y Cajal Programme (MINECO) RYC-2012-10651. J.L.R.-P. is funded by FIS 2014/173711/02568 and CIBERONC, and P.L.O.-R. by FIS 11/17592014/01784, from the Spanish Ministry of Health

EWS-FLI1 Utilizes Divergent Chromatin Remodeling Mechanisms to Directly Activate or Repress Enhancer Elements in Ewing Sarcoma

SummaryThe aberrant transcription factor EWS-FLI1 drives Ewing sarcoma, but its molecular function is not completely understood. We find that EWS-FLI1 reprograms gene regulatory circuits in Ewing sarcoma by directly inducing or repressing enhancers. At GGAA repeat elements, which lack evolutionary conservation and regulatory potential in other cell types, EWS-FLI1 multimers induce chromatin opening and create de novo enhancers that physically interact with target promoters. Conversely, EWS-FLI1 inactivates conserved enhancers containing canonical ETS motifs by displacing wild-type ETS transcription factors. These divergent chromatin-remodeling patterns repress tumor suppressors and mesenchymal lineage regulators while activating oncogenes and potential therapeutic targets, such as the kinase VRK1. Our findings demonstrate how EWS-FLI1 establishes an oncogenic regulatory program governing both tumor survival and differentiation

RAB7 Controls Melanoma Progression by Exploiting a Lineage-Specific Wiring of the Endolysosomal Pathway

Although common cancer hallmarks are well established, lineage-restricted oncogenes remain less understood. Here, we report an inherent dependency of melanoma cells on the small GTPase RAB7, identified within a lysosomal gene cluster that distinguishes this malignancy from over 35 tumor types. Analyses in human cells, clinical specimens, and mouse models demonstrated that RAB7 is an early-induced melanoma driver whose levels can be tuned to favor tumor invasion, ultimately defining metastatic risk. Importantly, RAB7 levels and function were independent of MITF, the best-characterized melanocyte lineage-specific transcription factor. Instead, we describe the neuroectodermal master modulator SOX10 and the oncogene MYC as RAB7 regulators. These results reveal a unique wiring of the lysosomal pathway that melanomas exploit to foster tumor progression.M.S.S. is funded by Projects SAF2011-28317 and Consolider RNAREG from the Spanish Ministry of Economy and Innovation, R01CA125017 from the NIH, and a Team Science Award by the Melanoma Research Foundation. J.L.R.-P. and P.O.-R. are funded by grants FIS 11/025685 and FIS 11/1759, respectively, from the Spanish Ministry of Health. J.L.R.-P. was also supported by grant FMM-2008-106 of Fundación Mutua Madrileña, and P.O.-R. by Red Tematica de Investigacion Cooperativa en Cancer. D.A.-C. and E.P.-G. are recipients of Scientists in Training predoctoral fellowships from the Spanish Ministry of Science and Innovation. M.C. and P.K. are funded by predoctoral fellowships of Fundación La Caixa. E.R.-F. is the recipient of a postdoctoral fellowship from Fundación Científica de la Asociación Española Contra el Cáncer, and J.A.J. and H.-W.W. are funded by the American Cancer Society (RSG-12-076-01-LIB)

Intermittent hypoxia is associated with high hypoxia inducible factor-1α but not high vascular endothelial growth factor cell expression in tumors of cutaneous melanoma patients

Epidemiological associations linking between obstructive sleep apnea and poorer solid malignant tumor outcomes have recently emerged. Putative pathways proposed to explain that these associations have included enhanced hypoxia inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF) cell expression in the tumor and altered immune functions via intermittent hypoxia (IH). Here, we examined relationships between HIF-1α and VEGF expression and nocturnal IH in cutaneous melanoma (CM) tumor samples. Prospectively recruited patients with CM tumor samples were included and underwent overnight polygraphy. General clinical features, apnea-hypopnea index (AHI), desaturation index (DI4%), and CM characteristics were recorded. Histochemical assessments of VEGF and HIF-1α were performed, and the percentage of positive cells (0, 75%) was blindly tabulated for VEGF expression, and as 0, 0-5.9, 6.0-10.0, >10.0% for HIF-1α expression, respectively. Cases with HIF-1α expression >6% (high expression) were compared with those 75% of cells was compared with those with <75%. 376 patients were included. High expression of VEGF and HIF-1α were seen in 88.8 and 4.2% of samples, respectively. High expression of VEGF was only associated with increasing age. However, high expression of HIF-1α was significantly associated with age, Breslow index, AHI, and DI4%. Logistic regression showed that DI4% [OR 1.03 (95% CI: 1.01-1.06)] and Breslow index [OR 1.28 (95% CI: 1.18-1.46)], but not AHI, remained independently associated with the presence of high HIF-1α expression. Thus, IH emerges as an independent risk factor for higher HIF-1α expression in CM tumors and is inferentially linked to worse clinical CM prognostic indicators