Quantitative Analysis of Integrin α6 in Bladder Cancer Cell Lines

The integrins, a family of transmembrane proteins, function in cell-to-cell and cell-to-extracellular matrix (ECM) adhesive interactions, and influence cell signaling of cell growth and differentiation. Expression of integrin 6 in three bladder cancer cell lines, HCV29, KK47 and YST1 were quantitatively analyzed by LC-MS using stable isotope labeling by amino acids in cell culture (SILAC), a simple and powerful proteomic strategy. The results showed that the non-invasive bladder cancer cell line KK47 expressed the highest level of integrin alpha 6. The expression of integrin alpha 6 in invasive bladder cancer cell line YTS1 was also higher than in normal bladder epithelial cell line HCV29. Furthermore, these results were confirmed by Western blotting, qPCR, immunohistochemistry and flow cytometry. Clinical data of mRNA 1TGA6 expression pattern from open-access database (www.oncomine.org) showed the same result during bladder cancer progression. All these indicated that integrin alpha 6 is associated with the invasion progress of the bladder cancer. The preliminary data in this study may sparkle the fundamental role of integrin 6 in the research of bladder cancer.