Effect of small interfering RNAs of cytochrome P450 17α‐hydroxylase/17,20‐lyase (CYP17) on androgen biosynthesis in theca cells

Polycystic ovary syndrome (PCOS) is associated with a variety of endocrinologic and metabolic abnormalities, with clinical features of hyperandrogenism and hyperandrogenemia. Cytochrome P450 17alpha-hydroxylase/17,20-lyase (CYP17) is critical in androgen biosynthesis, and CYP17 mRNA expression was proven augmented in PCOS theca cells. To demonstrate whether RNA interference (RNAi) could lower the androgen concentration in theca cells, small interfering RNA (siRNA) targeting the CYP17 gene was co-cultured with exogenous CYP17 in HeLa cells and endogenous CYP17 of theca cells. CYP17 gene expression was measured by fluorescent microscopy, flow cytometry and real-time reverse transcription-polymerase chain reaction analysis. Androstenedione and progesterone concentrations were measured by ELISA. RNAi effectively reduced the expression of exogenous CYP17 in HeLa cells by up to 50%. The CYP17 mRNA and androstenedione production of theca cells were slightly, but not significantly, reduced when compared with non-specific siRNA.