Overexpression of Pim-1 in bladder cancer

Abstract. background. pim-1 is a serine-threonine kinase which promotes early transformation,cell proliferation and cell survival during tumorigenesis. several studies have demonstrated that pim-1 kinase play a role in different cancer types,however,the function of pim-1 in bladder cancer is poorly understood. methods. expression and localization of pim-1 in human normal and malignant bladder specimens were examined by immunohistochemistry and pim-1 staining score was compared with several clinicopathologic parameters. to further demonstrate the biological function of pim-1 in bladder cancer,its expression was validated in five bladder cancer cell lines by western blot and immunohistochemistry analyses. subsequent knockdown of pim-1 was achieved by lentivirus encoding small interfering rna,and the effect of pim-1 on bladder cell survival and drug sensitivity were further assessed by colony formation and cell proliferation assays. results. when compared with normal epithelium,pim-1 was overexpressed in bladder cancer epithelium,and the expression level was higher in invasive bladder cancer than non-invasive bladder cancer specimens. pim-1 was also detected in all the bladder cancer cell lines examined in our study. moreover,the knockdown of pim-1 significantly inhibited bladder cancer cell growth and also sensitized cells to chemotherapeutic drugs in vitro. conclusions. our results in this study suggest that pim-1 may play a role in bladder cancer initiation and progression. since pim-1 is also involved in bladder cancer cell survival and drug resistance,pim-1 is a potential candidate for targeted therapy in bladder cancer. © 2010 guo et al; licensee biomed central ltd.