RT Journal Article T1 Epigenetic and post-transcriptional regulation of somatostatin receptor subtype 5 (SST5 ) in pituitary and pancreatic neuroendocrine tumors. A1 Pedraza-Arevalo, Sergio A1 Ibañez-Costa, Alejandro A1 Blazquez-Encinas, Ricardo A1 Branco, Miguel R A1 Vazquez-Borrego, Mari C A1 Herrera-Martinez, Aura D A1 Venegas-Moreno, Eva A1 Serrano-Blanch, Raquel A1 Arjona-Sanchez, Alvaro A1 Galvez-Moreno, Maria A A1 Korbonits, Marta A1 Soto-Moreno, Alfonso A1 Gahete, Manuel D A1 Charalambous, Marika A1 Luque, Raúl M A1 Castaño, Justo P K1 SST5 K1 Epigenetics K1 Natural antisense transcript K1 Neuroendocrine tumors K1 Pancreas K1 Pituitary AB Somatostatin receptor subtype 5 (SST5 ) is an emerging biomarker and actionable target in pituitary (PitNETs) and pancreatic (PanNETs) neuroendocrine tumors. Transcriptional and epigenetic regulation of SSTR5 gene expression and mRNA biogenesis is poorly understood. Recently, an overlapping natural antisense transcript, SSTR5-AS1, potentially regulating SSTR5 expression, was identified. We aimed to elucidate whether epigenetic processes contribute to the regulation of SSTR5 expression in PitNETs (somatotropinomas) and PanNETs. We analyzed the SSTR5/SSTR5-AS1 human locus in silico to identify CpG islands. SSTR5 and SSTR5-AS1 expression was assessed by quantitative real-time PCR (qPCR) in 27 somatotropinomas, 11 normal pituitaries (NPs), and 15 PanNETs/paired adjacent (control) samples. We evaluated methylation grade in four CpG islands in the SSTR5/SSTR5-AS1 genes. Results revealed that SSTR5 and SSTR5-AS1 were directly correlated in NP, somatotropinoma, and PanNET samples. Interestingly, selected CpG islands were differentially methylated in somatotropinomas compared with NPs. In PanNETs cell lines, SSTR5-AS1 silencing downregulated SSTR5 expression, altered aggressiveness features, and influenced pasireotide response. These results provide evidence that SSTR5 expression in PitNETs and PanNETs can be epigenetically regulated by the SSTR5-AS1 antisense transcript and, indirectly, by DNA methylation, which may thereby impact tumor behavior and treatment response. PB John Wiley & Sons YR 2021 FD 2021-09-06 LK http://hdl.handle.net/10668/22383 UL http://hdl.handle.net/10668/22383 LA en NO Pedraza-Arevalo S, Ibáñez-Costa A, Blázquez-Encinas R, Branco MR, Vázquez-Borrego MC, Herrera-Martínez AD, et al. Epigenetic and post-transcriptional regulation of somatostatin receptor subtype 5 (SST5 ) in pituitary and pancreatic neuroendocrine tumors. Mol Oncol. 2022 Feb;16(3):764-779 NO This research was funded by Junta de Andalucıa (BIO-0139, P20_00442; PEER-0048-2020); Spanish Ministry of Economy (BFU2016-80360-R), Ministry of Science and Innovation (PID2019-105201RB-I00, PID2019-105564RB-I00); and ISCIII (PI16-00264, CD19/00255), co-funded with EU funds from FEDER Program. People Programme (Marie Curie Actions) ofthe European Union’s Seventh Framework Programme (FP7/2007-2013) under project WHRI-ACADEMY, (FPU14/04290, FPU18/02275); EMBO (short term fellowship 6802); GETNE G2019 Research Grant; Fundacion Eugenio Rodriguez Pascual (FERP2019); project grants from the UK Medical Research Council (MR/R022836/1; MR/L002345/1); and CIBERobn; CIBERFisiopatología de la Obesidad y Nutrición is an initiative of Instituto de Salud Carlos III DS RISalud RD Apr 13, 2025