Objective: To elucidate the regulation of epidermal growth factor receptor (EGFR) expression by transforming growth factor (TGFalpha) and epidermal growth factor (EGF) in human prostate androgen-unresponsive cancer cells.
Methods: EGFR mRNA expression and its protein level were measured by means of RT-PCR and Western blot respectively in human prostate cancer androgen-unresponsive cell lines, ARCaP and PC3, all treated with exogenous TGFalpha.
Results: In the TGFalpha group, the levels of EGFR mRNA were 5.01 0.45 and 9.05 0.63 in PC3 and ARCaP respectively, significantly higher than in the control group (P < 0.05). The level of EGFR protein in PC3 treated with TGFalpha was 2.28 0.53, higher than in the control group (P < 0.05); however, the level of EGFR protein in ARCaP treated with TGFalpha was only 1.24 0.22, not different from the control (P > 0.05).
Conclusion: TGFalpha/EGF-EGFR pathway serves as a key growth regulator in prostate cancer. TGFalpha, but not EGF, preferentially maintains an autocrine loop in human androgen-unresponsive prostate cancer.