ABSTRACT
AR (androgen receptor) and CCAT2 are two prostate cancer (PCa)-related genes whereas their relationship is not yet reported. AR is the classical major functional gene in PCa progression. CCAT2, a non-coding gene, was identified based on big-data GWAS (Genome-Wide Association Studies) in the year of 2013. Androgen deprivation therapy (ADT) is usually used to treat PCa in the early stage. After persistent androgen deprivation, PCa would generally lead to castration resistant prostate cancer (CRPC), whereas the mechanism is yet unclear. Here we explore the function of AR and CCAT2 in PCa progression, especially their relation in androgen sensitive and insensitive cell model LNCap and DU145. We found a loop between AR and CCAT2 transcription by over-expression and knock-down strategies. In DU145 cells, G-CCAT2 activated AR mRNA level 2. 6 times, while T-CCAT2 inhibited it to 0. 2 times (P<0. 05). In LNCaP cells, G-CCAT2 could activate AR mRNA levels 1. 5 times, and TCCAT2 had no significant effect (P<0. 05). Under overexpression of AR in DU145 cells, the expression of CCAT2 increased 2. 9 times (P < 0. 05). The abundance of CCAT2 decreased to 0. 48 (P < 0. 05) in LNCaP cells by AR knock-down. Reporter gene analysis showed that CCAT2 could function on the AR promoter. We then performed CCK8 assays and AR protein level detection as supplement for the new gene CCAT2 studies. Finally we primarily studied some target genes that are related to AR and CCAT2 . The results showed that the G-CCAT2 transcript could activate AR expression in LNCap cells while UCCAT2 had no significant effect. In DU145 cells, G-CCAT2 exhibited a more relative stronger activation effect on AR, and U-CCAT2 could inhibit AR transcription. AR activates the transcriptional activity of CCAT2 in both cell lines, suggesting a feedback regulation between them. Our data showed that there would be a feedback loop between CCAT2 and AR, which may indicate a new method for PCa treatment.