Study Of The Role Of Gep100in Pancreatic Cancer Cell Invasion And Metastasis And Corresponding Molecular Mecnanism

Background:Invasion and metastasis are major reasons for pancreatic cancer death. It will be of great significance to identify the molecules that specifically used by cancer cell invasion and its underlying molecular mechanism. Recent study showed that GEP100was involved in breast cancer cell invasion, while its functional role in other cancers remains largely unknown and the molecular mechanism is elusive. The purpose of this study was to elucidate the role of GEP100in pancreatic cancer cell invasion and metastasis and its corresponding molecular mechanism.Methods:The expression of GEP100in six pancreatic cancer cell lines was investigated by using RT-PCR and western blot. The proper cell lines were chosen and transfected with GEP100shRNA plasmid to establish stable cell lines by selecting with puromycin. The abilities of invasion, adhesion, migration and proliferation were Matrigel invasion assay, collagen adhesion assay, crossing-river assay and MTT assay. Liver metastasis was investigated by spleen injection of the corresponding indicated cancer cells accompanied by splenectomy. The expressions of E-cadherin and its corresponding transcription factors were investigated with RT-PCR or western blot and intracellular localization of E-cadherin was examined by immunofluorescence study.Results:We found that:1) The expression levels of GEP100protein were closely related with the invasive abilities of different human pancreatic cancer cell lines.2) Down-regulation of GEP100in pancreatic cancer cells significantly decreased the invasive activity, without affecting viability, adhesion and migration. The inhibited invasive activity was rescued by over-expression of GEP100cDNA.3) In vivo study showed that liver metastasis was significantly inhibited in pancreatic cancer cells with GEP100stably knocked-down.4) An epithelial-like morphological change, mimicking a mesenchymal to epithelial transition (MET) was induced by GEP100down-regulation.5) The expression of E-cadherin protein was up-regulated by GEP100knock-down, while the mRNA expression of E-cadherin was not affected. The mRNA expression of Slug, one of the transcription factors, was increased.6) Redistribution of E-cadherin to the cell-cell contacts was induced by GEP100knock-down.Conclusion:These findings provide important evidence that GEP100plays a significant role in pancreatic cancer invasion through regulating the expression of E-cadherin and the process of mesenchymal to epithelial transiton, indicating its possibility of becoming a potential therapeutic target against pancreatic cancer.