[Effect of siRNA inhibiting HPV16 E6 gene expression on proliferation and cell cycle of cervical cancer cell line CaSki].

Objective: To observe whether human papillomavirus 16 (HPV16) E6-specific small interfering RNAs (siRNAs) can be employed to inhibit the growth of cervical cancer cell line, and to investigate the associated mechanism.
Methods: RNAi was performed using synthetic small interfering RNAs transferred into CaSki cell line by lipofectamine. The cell growth curves, live cell ratio and inhibition ratio of cells were measured by using cell counting. At various time points of post-transfection, the distributions of cell cycle, the expression levels of HPV16 E6, p53, p21 mRNA and proteins were detected by using flow cytometry (FCM) and real-time quantitative reverse transcription-polymerase chain reaction (real-time RT-PCR).
Results: The growth inhibition of E6 siRNA to CaSki cells was demonstrated after cells treated with E6 siRNA. No substantial G1 arrest was observed by FCM analysis. For 24 hours after cell transfection, the level of E6 mRNA was decreased by 20. 11 folds compared with control (P < 0.05). However, p53 and p21 mRNA levels appeared unaffected. 48 hours after cell transfection, the expression level of E6 protein was efficiently decreased, but the P53 and P21 protein levels increased in comparison.
Conclusions: The inhibitory effect of HPV16 E6 siRNA to CaSki cell maybe due to specially and efficiently silence E6 mRNA expression, decrease the degradation of wild type P53 protein, and then recover the function activity of P53 protein.