Enhanced expression of trophinin promotes invasive and metastatic potential of human gallbladder cancer cells

To study effects of trophinin on the metastatic potential of human gallbladder cancer cells and its potential mechanism. Expression of trophinin in the highly metastatic GBC-SDHi cells was investigated by real time RT-PCR and western blot. Recombinant expression plasmid vector of the human trophinin gene was constructed and transfected into GBC-SD cells. Effects of trophinin on the invasion of GBC-SD cells were investigated by adhesion assay and invasion assay in vitro. The siRNA was used to down-regulate the expression of trophinin. Some genes related to the invasion and metastasis of cancer were determined by real time RT-PCR and western blot. The pulmonary metastasis regulated by trophinin was determined in the nude mice. Overexpression of trophinin in GBC-SDHi cells was confirmed compared with its parental counterparts. Up-regulation of trophinin enhanced the in vitro invasion in the GBC-SD/TRO cells. The enhancement was associated with increasing integrin alpha 3, MMP-7, MMP-9, and Ets-1 expression. The results were further demonstrated by RNA interference experiment in vitro. In in vivo study, we also demonstrated that trophinin-transfected gallbladder cancer cells had more pulmonary metastases than the vector-transfected one or its parental counterparts. Overexpression of trophinin leads to a more invasive phenotype and metastatic potential in human gallbladder cancer, at least in part, through regulating integrin alpha 3, MMP-7, MMP-9, and Ets-1 expression.