WNT5A -: target of CUTL1 and potent modulator of tumor cell migration and invasion in pancreatic cancer

Previously, we have identified the transcription factor CUTL1 as an important mediator of tumor invasion and target of tumor growth factor-beta. Using high-throughput approaches, we identified several putative downstream effectors of CUTL1, among them WNT5A, a secreted member of the Wnt multigene family. The aim of this study was to investigate the role of WNT5A as a novel target of CUTL1 in pancreatic cancer. CUTL1 and WNT5A were stably over-expressed as well as transiently and stably knocked down by RNA interference. Effects on proliferation, migration and invasiveness were investigated by thymidine incorporation, Boyden chamber experiments and time-lapse microscopy. Expression of WNT5A in pancreatic cancer tissues was analyzed by real-time polymerase chain reaction (RT-PCR) and immunohistochemistry. We found that CUTL1 transcriptionally upregulated WNT5A on RNA, protein and promoter level. WNT5A significantly enhanced migration, proliferation and invasiveness, mediating the pro-invasive effects of CUTL1 to a major extent. WNT5A effects were accompanied by a marked modulation of marker genes associated with epithelial-mesenchymal transition. Using RT-PCR and immunohistochemistry, we found that WNT5A is up-regulated early during pancreatic cancerogenesis in pancreatic intraepithelial neoplasias lesions and in invasive pancreatic adenocarcinomas, as compared with normal pancreas tissues. These data identify WNT5A as important target of CUTL1 and as novel mediator of invasiveness and tumor progression in pancreatic cancer.