Abstract LB-128: High prevalence of elevated TRPV6 mRNA in pancreatic ductal adenocarcinoma

Abstract

Abstract SOR-C13, a 13-mer peptide derived from soricidin, the paralytic protein component of saliva of the Northern Short-tailed shrew, just completed an open-label, all comers phase I clinical trial for the treatment of epithelial-derived cancers. SOR-C13 is a first-in-class drug candidate that specifically targets and inhibits the TRPV6 calcium channel - a recognized oncochannel over-expressed in a number of epithelial cancers (e.g. breast, ovarian, prostate). TRPV6 over-expression is associated with a poor prognosis particularly with breast and prostate cancers. SOR-C13 is the first TRPV6-targeting drug to enter clinical development. Pancreatic patients were enrolled in the phase I clinical trial for SOR-C13 and for this reason the TRPV6 gene expression in pancreatic tumour biopsies was assessed. Association of TRPV6 oncochannel expression with aggressive pancreatic adenocarcinoma compared to neuroendocrine tumours has never been investigated. Pancreatic adenocarcinoma represents 90% of the pancreatic tumours and is associated with a poor prognosis compared to neuroendocrine tumours. TRPV6 gene expression was assessed in 19 pancreatic tumor biopsies including five adenocarcinoma (Grade I to III), one acinar cell (exocrine), and 13 neuroendocrine (Islet cell) tumors by two-step RT-qPCR. TRPV6 and β-actin (reference gene) mRNA expression was evaluated in duplicate in a reproducible TRPV6 plus β-actin duplex two-step RT-qPCR assay. The acinar cell, and 69% (9/13) of the neuroendocrine tumors had no detectable TRPV6 mRNA expression with >90% of neuroendocrine tumors (12/13) having very little TRPV6 mRNA expression (<30 copies/ng RNA). Of the five pancreatic adenocarcinoma biopsies 4/5 (80%) had 67-285 copies of TRPV6 mRNA/ng RNA, indicating a high level of TRPV6 expression in this type of aggressive pancreatic cancer. The β-actin CT was between 24 and 30 for all tumours (mean 28.5 ± 1.2) indicating that the lack TRPV6 amplification in a majority of the neuroendocrine tumors was not due to RT-qPCR failure or a lack of quality of the biopsy cDNA. Results indicate that drugs specifically targeting TRPV6 oncochannel, like SOR-C13, have the potential to be used to treat the high medical need in pancreatic ductal adenocarcinoma. Citation Format: Tyler Lutes, Dominique Dugourd, Michelle Davey, Christopher Rice, Stephanie St-Pierre, Jack M. Stewart. High prevalence of elevated TRPV6 mRNA in pancreatic ductal adenocarcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-128.