The effect of small interfering RNAs agaist cytochrome P450 17α-hydroxylase/17,20-lyase (CYP17) on androgen biosynthesis in theca cells obtained from women with polycystic ovarian syndrome

Objective: To investigate the effects of Cytochrome P450 17α-hydroxylase/17, 20-lyase(CYP17)small interfering RNA (siRNA) on the expression of CYP17 and androgen biosynthesis in theca cells from women with polycystic ovarian syndrome(PCOS). Methods: Four siRNAs targeting the CYP17 gene and one non-specific siRNA were synthesized. 0.4μg of plasmid, in which expressed the enhanced green fluorescent protein(EGFP)reporter gene, the CYP17 gene, and a siRNA were co-transfected into HeLa cells, After transfection the silencing EGFP was measured by fluorescence microscopy and flow cytometry. Theca cells were isolated from five women with PCOS and five women without PCOS then were cultured in the presence or absence of the most effective siRNA at the most effective concentration. After 72 hours in cultured, the media was collected to evaluate androstenedione and progesterone production. The suppressive effect of the siRNA on CYP17 mRNA was determined by real-time reverse transcription-polymerase chain reaction analysis. Results: Following treatment with siRNA 1221, the expression of exogenous CYP17 in HeLa cells was reduced by up to 50%. The CYP17 mRNA expression and androstenedione production of thecal cells were slightly, but not significantly,reduced compared to cell exposed to the non-specific siRNA. Conclusion:RNAi may have applications as gene therapy for reducing hyperandrogenism associated with PCOS.