Epidermal growth factor induces p38 MAPK-dependent G0/G1-to-S transition in prostate cancer cells upon androgen deprivation conditions

摘要

Epidermal growth factor (EGF) is thought to contribute to the emergence of castration-resistant (CR) prostate tumors by inducing proliferation of cancer cells despite the low levels of circulating androgens achieved by androgen deprivation therapy. We show that, in LNCaP cells, androgen deprivation induces arrest in the G(0)/G(1) cell cycle phase, and that EGF partially rescues this arrest without affecting cell death. Inhibition of p38 MAPK, but not MEK or IKK-, completely abrogates the EGF-induced proliferation of LNCaP cells in androgen-depleted medium, and decreases the fraction of G(0)/G(1)-arrested cells. Our results suggest that EGF enables prostate cancer cells to overcome the growth restriction imposed by androgen deprivation by stimulating G(0)/G(1)-to-S transition via p38 MAPK. These results suggest the potential of developing therapies for advanced prostate cancer that block the G(0)/G(1) to S transition, such as by targeting p38 MAPK, or that aim to induce apoptosis in G(0)/G(1)-arrested cancer cells.