BAF53A regulates androgen receptor-mediated gene expression and proliferation in LNCaP cells.

The actin-like protein of the SWI/SNF complex, BAF53A, regulates gene expression by the gene-specific chromatin remodeling of target genes. However, the function of BAF53A in the androgen receptor pathway in prostate cancer cells remains unclear. Here, we demonstrated that BAF53A positively regulates the expression of endogenous AR target genes (e.g. PSA, TMPRSS2, FKBP5, and KLK2) in LNCaP cells. It functions as a coactivator in AR-mediated transcription by interacting with other nuclear receptor coactivators, such as p300 and FLII, and is associated with AR in the presence of dihydrotestosterone (DHT). The DHT-induced recruitment of BAF53A to the proximal and distal androgen response elements (AREs) of the PSA gene in the presence of BRG1 (but not BRM) was inhibited by an AR antagonist, suggesting the coactivator function of BAF53A in the SWI/SNF complex. Depletion of BAF53A in LNCaP cells resulted in a significant decrease in growth rate. Furthermore, the expression of BAF53A in prostate cancer tissue was significantly elevated, compared to that in normal prostate tissue, and correlated with the expression of AR, and BRG1, but not BRM. Therefore, our results suggested that BAF53A plays an important role in the expression of AR target genes in prostate cancer, and can be used clinically for the treatment of prostate cancer.