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The endoplasmic reticulum (ER) of cancer cells needs to adapt to the enhanced proteotoxic stress associated with the accumulation of unfolded, misfolded and transformation-associated proteins. One way by which tumors thrive in the context of ER stress is by promoting ER-Associated Degradation (ERAD), although the mechanisms are poorly understood. Here, we show that the Small p97/VCP Interacting Protein (SVIP), an endogenous inhibitor of ERAD, undergoes DNA hypermethylation-associated silencing in tumorigenesis to achieve this goal. SVIP exhibits tumor suppressor features and its recovery is associated with increased ER stress and growth inhibition. Proteomic and metabolomic analyses show that cancer cells with epigenetic loss of SVIP are depleted in mitochondrial enzymes and oxidative respiration activity. This phenotype is reverted upon SVIP restoration. The dependence of SVIP hypermethylated cancer cells on aerobic glycolysis and glucose was also associated with sensitivity to an inhibitor of the glucose transporter GLUT1. This could be relevant to the management of tumors carrying SVIP epigenetic loss, because these occur in high-risk patients who manifest poor clinical outcomes. Overall, our study provides insights into how epigenetics helps deal with ER stress and how SVIP epigenetic loss in cancer may be amenable to therapies that target glucose transporters. ; This work was supported by the Health Department PERIS project number SLT/002/16/00374 and AGAUR project numbers 2017SGR1080, 2014SGR633, 2017SGR1033, and 2009SGR1315 of the Catalan Government (Generalitat de Catalunya); the Spanish Institute of Health Carlos III (ISCIII) project number DTS16/00153 and Ministerio de Economía y Competitividad (MINECO) project numbers SAF2014-55000-R, BFU2014-57466-P, SAF2017-89673-R, and SAF2015-70270-REDT co-financed by the European Development Regional Fund, A way to achieve Europe ERDF; the Cellex Foundation; and "la Caixa" Bank Foundation (LCF/PR/PR15/11100003). MC acknowledges the prize "ICREA Academia" for excellence in research, funded by ICREA foundation. We thank the Scientific and Technological Centre (CCiTUB) of the University of Barcelona for technical support with cell cytometry and sorting. We also thank the Regenerative Medicine Center (CMRB) Electron Microscopy and Histology facility.

Resultado clínico; Epitranscriptómica; Glioma ; Clinical outcome; Epitranscriptomics; Glioma ; Resultat clínic; Epitranscriptòmica; Glioma ; Tumors have aberrant proteomes that often do not match their corresponding transcriptome profiles. One possible cause of this discrepancy is the existence of aberrant RNA modification landscapes in the so-called epitranscriptome. Here, we report that human glioma cells undergo DNA methylation-associated epigenetic silencing of NSUN5, a candidate RNA methyltransferase for 5-methylcytosine. In this setting, NSUN5 exhibits tumor-suppressor characteristics in vivo glioma models. We also found that NSUN5 loss generates an unmethylated status at the C3782 position of 28S rRNA that drives an overall depletion of protein synthesis, and leads to the emergence of an adaptive translational program for survival under conditions of cellular stress. Interestingly, NSUN5 epigenetic inactivation also renders these gliomas sensitive to bioactivatable substrates of the stress-related enzyme NQO1. Most importantly, NSUN5 epigenetic inactivation is a hallmark of glioma patients with long-term survival for this otherwise devastating disease. ; This work was supported by a European Research Council (ERC) Advanced Grant under the European Community's Seventh Framework Program (FP7/2007-2013)/ERC Grant Agreement No. 268626—EPINORC project (to M. Esteller), the Ministerio de Economía y Competitividad (MINECO) under Grant No. SAF2014-55000-R (to M. Esteller) and the Instituto de Salud Carlos III (ISCIII), under the FIS PI16/01278 Project (to J. Seoane), the Integrated Project of Excellence no. PIE13/00022 (ONCOPROFILE) (to M. Esteller), CIBER 2016 CB16/12/00312 (CIBERONC) (to M. Esteller), co-financed by the European Development Regional Fund, 'A way to achieve Europe' ERDF, the AGAUR—Catalan Government (Project No. 2009SGR1315 and 2014SGR633) (to M. Esteller), the Cellex Foundation (to M. Esteller), Obra Social "La Caixa" (to M. Esteller), the CERCA Program and the Health and Science Departments of the Catalan Government (Generalitat de Catalunya) (to M. Esteller) and a grant from the National Health and Medical Research Council of Australia (APP1061551, to TP). M.W. Boudreau is a member of the NIH Chemistry-Biology Interface Training Program (T32-GM070421).

© 2019 The Authors. ; Somatic epigenetic inactivation of the DNA repair protein O6-methylguanine DNA methyltransferase (MGMT) is frequent in colorectal cancer (CRC); however, its involvement in CRC predisposition remains unexplored. We assessed the role and relevance of MGMT germline mutations and epimutations in familial and early-onset CRC. Mutation and promoter methylation screenings were performed in 473 familial and/or early-onset mismatch repair-proficient nonpolyposis CRC cases. No constitutional MGMT inactivation by promoter methylation was observed. Of six rare heterozygous germline variants identified, c.346C > T (p.H116Y) and c.476G > A (p.R159Q), detected in three and one families respectively, affected highly conserved residues and showed segregation with cancer in available family members. In vitro, neither p.H116Y nor p.R159Q caused statistically significant reduction of MGMT repair activity. No evidence of somatic second hits was found in the studied tumors. Case-control data showed over-representation of c.346C > T (p.H116Y) in familial CRC compared to controls, but no overall association of MGMT mutations with CRC predisposition. In conclusion, germline mutations and constitutional epimutations in MGMT are not major players in hereditary CRC. Nevertheless, the over-representation of c.346C > T (p.H116Y) in our familial CRC cohort warrants further research. ; This work was funded by the Spanish Ministry of Science, Innovation and Universities, co-funded by FEDER funds -a way to build Europe- [SAF2016-80888-R (LV), SAF2014-55000-R (ME), SAF2015-68016-R (GC/MP), Juan de la Cierva and Sara Borrell postdoctoral contracts (PM)]; Instituto de Salud Carlos III [DTS16/00153 (ME) and CIBERONC CB16/12/00234]; the Government of Catalonia [Pla Estratègic de Recerca i Innovació en Salut SLT002/16/0037, 2017SGR1282, 2017SGR1080, 2014SGR633 and 2009SGR1315]; and Fundación Olga Torres. We thank the CERCA/Generalitat de Catalunya Program for institutional support. This study has been enabled by COST Action CA17118.

Somatic epigenetic inactivation of the DNA repair protein O6-methylguanine DNA methyltransferase (MGMT) is frequent in colorectal cancer (CRC); however, its involvement in CRC predisposition remains unexplored. We assessed the role and relevance of MGMT germline mutations and epimutations in familial and early-onset CRC. Mutation and promoter methylation screenings were performed in 473 familial and/or early-onset mismatch repair-proficient nonpolyposis CRC cases. No constitutional MGMT inactivation by promoter methylation was observed. Of six rare heterozygous germline variants identified, c.346C > T (p.H116Y) and c.476G > A (p.R159Q), detected in three and one families respectively, affected highly conserved residues and showed segregation with cancer in available family members. In vitro, neither p.H116Y nor p.R159Q caused statistically significant reduction of MGMT repair activity. No evidence of somatic second hits was found in the studied tumors. Case-control data showed over-representation of c.346C > T (p.H116Y) in familial CRC compared to controls, but no overall association of MGMT mutations with CRC predisposition. In conclusion, germline mutations and constitutional epimutations in MGMT are not major players in hereditary CRC. Nevertheless, the over-representation of c.346C > T (p.H116Y) in our familial CRC cohort warrants further research ; This work was funded by the Spanish Ministry of Science, Innovation and Universities, co-funded by FEDER funds -a way to build Europe- [SAF2016-80888-R (LV), SAF2014-55000-R (ME), SAF2015- 68016-R (GC/MP), Juan de la Cierva and Sara Borrell postdoctoral contracts (PM)]; Instituto de Salud Carlos III [DTS16/00153 (ME) and CIBERONC CB16/12/00234]; the Government of Catalonia [Pla Estratègic de Recerca i Innovació en Salut SLT002/16/0037, 2017SGR1282, 2017SGR1080, 2014SGR633 and 2009SGR1315]; and Fundación Olga Torres. We thank the CERCA/Generalitat de Catalunya Program for institutional support. This study has been enabled by COST Action CA17118

Publisher's version (útgefin grein). ; Human tumors show altered patterns of protein isoforms that can be related to the dysregulation of messenger RNA alternative splicing also observed in transformed cells. Although somatic mutations in core spliceosome components and their associated factors have been described in some cases, almost nothing is known about the contribution of distorted epigenetic patterns to aberrant splicing. Herein, we show that the splicing RNA-binding protein CELF2 is targeted by promoter hypermethylation-associated transcriptional silencing in human cancer. Focusing on the context of breast cancer, we also demonstrate that CELF2 restoration has growth-inhibitory effects and that its epigenetic loss induces an aberrant downstream pattern of alternative splicing, affecting key genes in breast cancer biology such as the autophagy factor ULK1 and the apoptotic protein CARD10. Furthermore, the presence of CELF2 hypermethylation in the clinical setting is associated with shorter overall survival of the breast cancer patients carrying this epigenetic lesion. ; We thank CERCA Program/Generalitat de Catalunya for institutional support. This work was supported by the Health Department PERIS-project no. SLT/002/16/00374 and AGAURprojects nos. 2017SGR1080, 2014SGR633, and 2009SGR1315 of the Catalan Government (Generalitat de Catalunya); the Spanish Institute of Health Carlos III (ISCIII) project no. DTS16/00153 and Ministerio de Economía y Competitividad (MINECO) project no. SAF2014–55000-R, co-financed by the European Development Regional Fund, "A way to achieve Europe" ERDF; the Cellex Foundation; and "la Caixa" Banking Foundation (LCF/PR/PR15/ 11100003). ; Peer Reviewed

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Download ; Human tumors show altered patterns of protein isoforms that can be related to the dysregulation of messenger RNA alternative splicing also observed in transformed cells. Although somatic mutations in core spliceosome components and their associated factors have been described in some cases, almost nothing is known about the contribution of distorted epigenetic patterns to aberrant splicing. Herein, we show that the splicing RNA-binding protein CELF2 is targeted by promoter hypermethylation-associated transcriptional silencing in human cancer. Focusing on the context of breast cancer, we also demonstrate that CELF2 restoration has growth-inhibitory effects and that its epigenetic loss induces an aberrant downstream pattern of alternative splicing, affecting key genes in breast cancer biology such as the autophagy factor ULK1 and the apoptotic protein CARD10. Furthermore, the presence of CELF2 hypermethylation in the clinical setting is associated with shorter overall survival of the breast cancer patients carrying this epigenetic lesion. ; Health Department PERIS-project of the Catalan Government (Generalitat de Catalunya) AGAUR of the Catalan Government (Generalitat de Catalunya) Instituto de Salud Carlos III Ministerio de Economia y Competitividad (MINECO) European Union (EU) Foundation CELLEX La Caixa Foundation

Tumors have aberrant proteomes that often do not match their corresponding transcriptome profiles. One possible cause of this discrepancy is the existence of aberrant RNA modification landscapes in the so-called epitranscriptome. Here, we report that human glioma cells undergo DNA methylation-associated epigenetic silencing of NSUN5, a candidate RNA methyltransferase for 5-methylcytosine. In this setting, NSUN5 exhibits tumor-suppressor characteristics in vivo glioma models. We also found that NSUN5 loss generates an unmethylated status at the C3782 position of 28S rRNA that drives an overall depletion of protein synthesis, and leads to the emergence of an adaptive translational program for survival under conditions of cellular stress. Interestingly, NSUN5 epigenetic inactivation also renders these gliomas sensitive to bioactivatable substrates of the stress-related enzyme NQO1. Most importantly, NSUN5 epigenetic inactivation is a hallmark of glioma patients with long-term survival for this otherwise devastating disease. ; This work was supported by a European Research Council (ERC) Advanced Grant under the European Community's Seventh Framework Program (FP7/2007-2013)/ERC Grant Agreement No. 268626—EPINORC project (to M. Esteller), the Ministerio de Economía y Competitividad (MINECO) under Grant No. SAF2014-55000-R (to M. Esteller) and the Instituto de Salud Carlos III (ISCIII), under the FIS PI16/01278 Project (to J. Seoane), the Integrated Project of Excellence no. PIE13/00022 (ONCOPROFILE) (to M. Esteller), CIBER 2016 CB16/12/00312 (CIBERONC) (to M. Esteller), co-financed by the European Development Regional Fund, 'A way to achieve Europe' ERDF, the AGAUR—Catalan Government (Project No. 2009SGR1315 and 2014SGR633) (to M. Esteller), the Cellex Foundation (to M. Esteller), Obra Social "La Caixa" (to M. Esteller), the CERCA Program and the Health and Science Departments of the Catalan Government (Generalitat de Catalunya) (to M. Esteller) and a grant from the National Health and Medical Research Council of Australia (APP1061551, to TP). M.W. Boudreau is a member of the NIH Chemistry-Biology Interface Training Program (T32-GM070421).