Open AccessFunctional analysis of a CDKN2A 5’UTR germline variant associated with pancreatic cancer development
Author(s) -
William Bruno,
Virginia Andreotti,
Alessandra Bisio,
Lorenza Pastorino,
Giuseppe Fornarini,
Stefania Sciallero,
Giovanna BianchiScarrà,
Alberto Inga,
Paola Ghiorzo
Publication year - 2017
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0189123
Subject(s) - internal ribosome entry site , untranslated region , cdkn2a , biology , germline , germline mutation , genetics , five prime untranslated region , cancer research , three prime untranslated region , microbiology and biotechnology , mutation , gene , translation (biology) , messenger rna
CDKN2A coding region germline variants are associated with pancreatic adenocarcinoma (PC) susceptibility. Recently, we described functional germline 5’UTR CDKN2A variants from melanoma patients affecting the post-transcriptional regulation of p16 INK4a mRNA that is dependent, at least in part, on an Internal Ribosome Entry Site (IRES) in the 5’UTR region. Here we describe a 5’UTR c.-201_-198delinsCTTT CDKN2A variant (frequency 0.0028 based on 350 PC patients), which seems to be private to PC, since it has never been found in public databases nor in thousands of melanoma patients tested. Functional analyses confirmed IRES activity of the 5’UTR in BX-PC3 PC cells and revealed a functional impact of the identified variant. Using gene reporter assays we observed reduced translation potential in cells treated with the mTOR inhibitor Torin1, a condition that favors the assessment of IRES activity. At the endogenous gene level we quantified allelic imbalance among polysome-associated mRNAs using a patient-derived cell line heterozygous for the c.-201_-198delinsCTTT. Overall, we conclude that this very rare private variant can be considered a potential mutation, specifically associated with PC. Our data indicate that sequencing of the entire 5'UTR of CDKN2A should be included in routine screening of PC cases with suspected inherited susceptibility.