Chrysotobibenzyl inhibition of lung cancer cell migration through Caveolin-1-dependent mediation of the integrin switch and the sensitization of lung cancer cells to cisplatin-mediated apoptosis

Background: A Lung cancer death account for approximately 1 in 5 of all cancer-related deaths and is particularly virulent due to its enhanced metastasis and resistance to chemotherapy. Chrysotobibenzyl has been reported to decrease cell metastasis, according to the results of an anchorage-independent growth assay; however, its underlying mechanism has not been investigated yet. Purpose: The aim of this study was to investigate the effect of chrysotobibenzyl on lung cancer cell migration and drug sensitization and its mechanism. Methods: Cell viability, cell proliferation and drug sensitization were determined by MTT assay. Cell migration was analyzed using a wound-healing assay. Transwell migration and invasion were analyzed using Boyden chamber assay. Mechanisms of chrysotobibenzyl against metastasis including cell migration, invasion, and epithelial to mesenchymal transition (EMT) were evaluated by Western blot analysis and immunofluorescence. Results: Treatment with chrysotobibenzyl was applied at concentrations of 0-50 mu M and the results showed non-cytotoxicity in human lung cancer cells (H460, H292, A549, and H23) and other non-cancerous human cells (HCT116, primary DP1 and primary DP2). However, 50 mu M of chrysotobibenzyl significantly altered cell proliferation in H292 cells at 48 h. In addition, 1-50 mu M of chrysotobibenzyl significantly inhibited H460 and H292 cell migration, invasion, filopodia formation, and decreased EMT in a dose-dependent manner at 48 h, which were correlated with reduced protein levels of integrins beta 1, beta 3, and alpha nu, p-FAK, p-AKT, Cdc42, and Cav-1. We also established shRNA-Cav-1-transfected (shCav-1) H460 and H292 cells. shCav-1 transfected cells can decrease cell migration and downregulate the expression of integrins beta 1, beta 3, and alpha nu when compared with the control. Moreover, chrysotobibenzyl was shown to suppress EMT indicated by the reduction of EMT markers (Vimentin, Snail, and Slug), and sensitize lung cancer cells to cisplatin-mediated apoptosis. Conclusion: Treatment with chrysotobibenzyl inhibited lung cancer cell migration via Cav-1, integrins beta 1, beta 3, and alpha nu, and EMT suppressions. The downregulation of integrins in response to the compound not only inhibited cell metastasis, but also sensitized lung cancer cells to cisplatin-mediated apoptosis.