[Kindlin-2 promotes gallbladder cancer metastasis and invasion by inducing epithelial-mesenchymal transition]

Objective: To investigate the effects of Kindlin-2 on malignant phenotypes of human gallbladder cancer cells and discuss the mechanisms. Methods: The expression level of Kindlin-2 in 30 cases of gallbladder cancer tissues and adjacent non-tumoral tissues collected from the First Affiliated Hospital of Zhengzhou University between September 2012 and May 2013 was assessed by real-time PCR and immunohistochemistry.Lentivirus-mediated Kindlin-2 overexpression was used in gallbladder cancer cell lines GBC-SD and SGC-996.Transwell assay and adhesion assay were investigated to explore the functional role of Kindlin-2 on gallbladder cancer cells.Western Blot was used to test the protein change of epithelial-mesenchymal transition(EMT) characteristics. The t-test was used to analyzed results. Results: The RNA and protein levels of Kindlin-2 in gallbladder cancer tissues were higher than in the non-tumoral tissues (t=4.372, P=0.001; t=7.477, P=0.000). The expression level of Kindlin-2 in gallbladder cancer tissues was correlated with Nevin stage(χ(2)=5.932, P=0.035). Compared with control groups, the cell-matrix adhesion ability of GBC-SD and SGC-996 with Kindlin-2 overexpression was obviously promoted(1.66±0.03 vs. 1.07±0.22, t=2.710, P=0.041; 2.66±0.24 vs. 1.03±0.02, t=6.610, P=0.020). The number of GBC-SD and SGC-996 cells with Kindlin-2 overexpression passing through the Transwell chamber matrix increased significantly compared with the control groups(116.1±13.9 vs. 54.7±8.4, t=3.781, P=0.019; 136.3±7.5 vs. 64.3±6.4, t=7.302, P=0.002). The wound healing rate of GBC-SD with Kindlin-2 overexpression at 12-hour and 24-hour was higher than that of the group ((42.9±2.2)% vs. (29.7±1.7)%, t=4.690, P=0.009; (65.0±2.4)% vs.(40.4±2.0)%, t=7.945, P=0.001). The wound healing rate of SGC-996 with Kindlin-2 overexpression at 12-hour and 24-hour was also higher than that of the group ((32.9±1.3)% vs. (24.1±1.5)%, t=4.518, P=0.011; (51.3±1.1)% vs. (39.2±1.1)%, t=8.001, P=0.001). The characteristics of EMT were induced in gallbladder cancer cells with Kindlin-2 overexpression, including the up-regulation of N-cadherin, Vemintin and the down-regulation of E-cadherin. Conclusion: The expression of Kindlin-2 is up-regulated in gallbladder cancer tissues and Kindlin-2 promoted the malignant phenotypes of gallbladder cancer cells partially by epithelial-mesenchymal transition.