Objective  This study investigates the growth inhibition effect of small interfering RNA (siRNA) targeting Phosphoinositide 3-kinase Regulatory Subunit p85 alpha (PI3Kp85α) on ovarian carcinoma cells.

  Methods  RNA interference (RNAi) technology was used to observe the inhibitory effect of siRNA on the growth of human ovarian carcinoma SKOV3 cells. The expression of PI3Kp85α mRNA was detected through real-time polymerase chain reaction after the transfection. The expression of PI3Kp85α, AKT1, AKT2, and Ki-67 was also studied using Western blot and immunofluorescence staining after transfection. Moreover, MTT methods and annexin V staining were used to evaluate cell proliferation and apoptosis. Flow cytometry was used for cell cycle analysis, and tumor invasion was examined through Transwell analysis.

  Results  SKOV3 PI3Kp85α mRNA expression was significantly knocked down after transfection with siRNA. The SKOV3 cells transfected with siRNA targeting PI3Kp85α showed lower proliferation activity, whereas the expression of PI3Kp85α, AKT1, AKT2, and Ki-67 was downregulated compared with the control and nonsense siRNA transfected cells. The transfected cells had higher apoptosis rate and most cells arrested in the G₀/G₁ phase. Moreover, the migration and invasive ability of the ovarian carcinoma cells was attenuated.

  Conclusion  Silencing PI3Kp85α genes with siRNA downregulated the mRNA expression of PI3Kp85α in ovarian carcinoma endothelial cells, blocked cell proliferation and migration, arrested cell cycle, and induced apoptosis in vitro. Therefore, P13Kp85α can be a candidate gene for ovarian cancer gene therapy.