Objective: To study whether TGF-α possesses similar EGF effect of enforcing neuroendocrine differentiation (NED) in prostate cancer cell line DU145 and determine the influence of NED induced by TGF-α on chemoresistance.
Methods: DU145 cells were divided into 3 groups: a group with 2% FBS, a group with 2%FBS+TGF-α 5 ng/mL and a group with 2%FBS+TGF-α 10 ng/mL. Morphological change in DU145 cells was observed after TGF-α treatment. Expression levels of NSE mRNA were detected with real time RT-PCR. Western blot was used to detect the expression levels of protein NSE, P-gp, MRP1 and Bcl-2. Cell cycles of DU145 cells in the 3 groups were examined with flow cytometry. MTT assay was used to evaluate the influence of TGF-α in chemoresistance.
Results: Compared with DU145 cells cultured with 2% FBS, cells treated with 2% FBS+TGF-α were pleomorphic and pseudopodia extended. The expression level of NSE mRNA upregulated to (3.6±0.5) folds (P<0.05) and (10.1±0.1) folds (P<0.01). Western blot showed that the expression levels of protein NSE, Bcl-2, and MRP1 increased after treatment with different concentrations of TGF-α; P-gp was not detected. The proportion of DU145 cells in phase G1 decreased; proportions of cells in phase S and phase G2/M were increased after TGF-α treatment (5 μg/mL). At the same time, chemoresistance of DU145 cells to cisplatin increased.
Conclusion: TGF-α can increase NED in DU145 cells and enforce the chemoresistance to cisplatin.