[PKD3 contributes to up-regulation of prostate-specific antigen in prostate cancer cells].

Objective: To investigate the role of PKD3 in prostate-specific antigen (PSA) expression regulation in androgen-dependent prostate cancer cells and explore the mechanism.
Methods: LNCaP cells containing low level of PKD3 were transfected with pEGFP-C2 or pEGFP-PKD3 plasmid followed by dihydrotestosterone (DHT) treatment, and PSA mRNA level was analyzed by RT-QPCR using 2(-delta delta Ct) method. Wild-type or kinase-dead PKD3 plasmids, human androgen receptor plasmid pSVAR0, pMMTV-luc of AR luciferase reporter and renilla luciferase reporter pRL-SV40 were cotransfected into HEK293 cells, and after treatment with DHT for 24 h, the cells were harvested and AR transcriptional activity were determined by dual-luciferase reporter assay. The subcellular localization of endogenous PKD3 and AR and their colocalization induced by DHT were observed by confocal microscopy.
Results: PSA mRNA level triggered by DHT was significantly increased by overexpression of pEGFP-PKD3 in LNCaP cells compared with that in pEGFP-C2 control cells (P<0.001). AR transcription in response to DHT treatment was also significantly up-regulated by wild type PKD3 expression (P<0.001), but partially down-regulated by kinase-dead PKD3 mutant (P<0.01). Endogenous PKD3 and AR in LNCaP cells not only translocated from the cytoplasm to the nucleus, but also colocalized with each other after DHT stimulation.
Conclusion: Elevated AR transcriptional activity and enhanced expression of PSA induced by PKD3 in response to DHT treatment suggest that PKD3 contributes to the proliferation and malignant growth of androgen-dependent prostate cancer cells.