Abstract: To investigate the change of mitogen activated protein kinase(MAPK) signaling pathway during prostate cancer progression, and therefore to explore its role on cell proliferation. Methods: MTT assay was used to examine the effects of epidermal growth factor (EGF) and PD98059 on proliferation of prostate cancer cell lines LNCaP, PC3 and DU145, and western blotting to detect the level of total extracellular signalregulated kinase 1/2 (ERK1/2), the level of phosphoERK1/2 before and after the EGF stimulation and PD98059 inhibition. Results: EGF promoted the prostate cancer cell growth, whereas PD98059 inhibited the cell growth and stopped the EGF from stimulating the LNCaP, PC3 and DU145 cells. The total ERK1/2 level was not significantly different in the three cell lines, whereas the phosphoERK1/2 was not detected with western blotting in LNCaP cell line and ERK1/2 activity was found in PC3 and DU145. Conclusion: The MAPK transpass activity is promoted during the prostate cancer progression, suggesting that blocking the MAPK transpass can be used as a method for prostate cancer therapy.

Key words: Prostatic neoplasms, Protein kinases, Mitogens