Targeted dual inhibition of c-Met/VEGFR2 signalling by foretinib improves antitumour effects of nanoparticle paclitaxel in gastric cancer models.

Elevated expression of multiple growth factors and receptors including c-Met and VEGFR has been reported in gastric adenocarcinoma (GAC) and thus provides a potentially useful therapeutic target. The therapeutic efficacy of foretinib, a c-Met/VEGFR2 inhibitor, was determined in combination with nanoparticle paclitaxel (NPT) in GAC. Animal studies were conducted in NOD/SCID mice in subcutaneous and peritoneal dissemination xenografts. The mechanism of action was assessed by Immunohistochemical and Immunoblot analyses. In c-Met overexpressing MKN-45 cell-derived xenografts, NPT and foretinib demonstrated inhibition in tumour growth, while NPT plus foretinib showed additive effects. In c-Met low-expressing SNU-1 or patient-derived xenografts, the foretinib effect was smaller, while NPT had a similar effect compared with MKN-45, as NPT plus foretinib still exhibited an additive response. Median mice survival was markedly improved by NPT (83%), foretinib (100%) and NPT plus foretinib (230%) in peritoneal dissemination xenografts. Subcutaneous tumour analyses exhibited that foretinib increased cancer cell death and decreased cancer cell proliferation and tumour vasculature. NPT and foretinib suppressed the proliferation of GAC cells in vitro and had additive effects in combination. Further, foretinib caused a dramatic decrease in phosphorylated forms of c-Met, ERK, AKT and p38. Foretinib led to a decrease in Bcl-2, and an increase in p27, Bax, Bim, cleaved PARP-1 and cleaved caspase-3. Thus, these findings highlight the antitumour impact of simultaneous suppression of c-Met and VEGFR2 signalling in GAC and its potential to enhance nanoparticle paclitaxel response. This therapeutic approach might lead to a clinically beneficial combination to increase GAC patients' survival.

Alternative polyadenylation drives oncogenic gene expression in pancreatic ductal adenocarcinoma.

Alternative polyadenylation (APA) is a gene regulatory process that dictates mRNA 3'-UTR length, resulting in changes in mRNA stability and localization. APA is frequently disrupted in cancer and promotes tumorigenesis through altered expression of oncogenes and tumor suppressors. Pan-cancer analyses have revealed common APA events across the tumor landscape; however, little is known about tumor type-specific alterations that may uncover novel events and vulnerabilities. Here, we integrate RNA-sequencing data from the Genotype-Tissue Expression (GTEx) project and The Cancer Genome Atlas (TCGA) to comprehensively analyze APA events in 148 pancreatic ductal adenocarcinomas (PDACs). We report widespread, recurrent, and functionally relevant 3'-UTR alterations associated with gene expression changes of known and newly identified PDAC growth-promoting genes and experimentally validate the effects of these APA events on protein expression. We find enrichment for APA events in genes associated with known PDAC pathways, loss of tumor-suppressive miRNA binding sites, and increased heterogeneity in 3'-UTR forms of metabolic genes. Survival analyses reveal a subset of 3'-UTR alterations that independently characterize a poor prognostic cohort among PDAC patients. Finally, we identify and validate the casein kinase CSNK1A1 (also known as CK1alpha or CK1a) as an APA-regulated therapeutic target in PDAC. Knockdown or pharmacological inhibition of CSNK1A1 attenuates PDAC cell proliferation and clonogenic growth. Our single-cancer analysis reveals APA as an underappreciated driver of protumorigenic gene expression in PDAC via the loss of miRNA regulation.