Peroxisome proliferator-activated receptor γ coactivator-1α interacts with the androgen receptor (AR) and promotes prostate cancer cell growth by activating the AR

There are currently few successful therapies for castration-resistant prostate cancer (CRPC). CRPC is thought to result from augmented activation of the androgen/androgen receptor (AR) signaling pathway, which could be enhanced by AR cofactors. In this study, peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) was found to be an AR cofactor. PGC-1α interacted with the N-terminal domain of AR, was involved in the N- and C-terminal interaction of AR, and enhanced the DNA-binding ability of AR to androgen-responsive elements in the prostate-specific antigen enhancer and promoter regions to increase the transcription of AR target genes. Silencing of PGC-1α suppressed cell growth of AR-expressing prostate cancer (PCa) cells by inducing cell-cycle arrest at the G₁ phase, similar to inhibition of androgen/AR signaling. Furthermore, PGC-1α knock-down also suppressed cell growth in the castration-resistant LNCaP-derivatives. These findings indicate that PGC-1α is involved in the proliferation of AR-expressing PCa cells by acting as an AR coactivator. Modulation of PGC-1α expression or function may offer a useful strategy for developing novel therapeutics for PCa, including CRPC, which depends on AR signaling by over-expressing AR and its coactivators.