Expression of TMEFF2 in Human Pancreatic Cancer Tissue and the Effects of TMEFF2 Knockdown on Cell, Proliferation, and Apoptosis in Human Pancreatic Cell Lines.

BACKGROUND The TMEFF2 gene encodes the transmembrane protein with EGF like and two follistatin-like domains 2 and has been reported to be a tumor suppressor gene, but its role remains unknown in pancreatic cancer. This study aimed to investigate the expression of TMEFF2 in human pancreatic cancer tissue and the effects of knockdown of TMEFF2 on cell, proliferation, and apoptosis in human pancreatic cell lines. MATERIAL AND METHODS Thirty-five samples of human pancreatic tissue and adjacent normal pancreatic tissue, and five human pancreatic cancer cell lines, CAPAN1, ASPC1, BXPC3, SW1990, and CFPAC were studied. RNA expression, protein expression, cell proliferation, and apoptosis were studied using real-time polymerase chain reaction (RT-PCR), Western blot, the cell counting kit-8 (CCK-8) assay, and flow cytometry, respectively. A co-immunoprecipitation assay evaluated protein interactions. RESULTS TMEFF2 expression was down-regulated in pancreatic cancer tissue compared with normal pancreas. In human pancreatic cancer cell lines, overexpression of TMEFF2 suppressed cell proliferation and enhanced apoptosis, suppressed the expression of p-STAT3, MCL1, VEGF and increased the expression of the tyrosine-specific protein phosphatase, SHP-1. The co-immunoprecipitation assay showed that TMEFF2 interacted with SHP-1. Knockdown of expression of TMEFF2 resulted in the increased expression of p-STAT3, MCL1, and VEGF, increased cell proliferation and decreased cell apoptosis, which were reversed by overexpression of SHP-1. CONCLUSIONS In pancreatic cancer, TMEFF2 exerted as a tumor suppressor effect by regulating p-STAT3, MCL1, and VEGF via SHP-1.