Suppression of E6 Oncogene Induces Apoptosis in CaSki Cervical Cancer Cells.

Objective: The most important casuse of cervical cancer incidence and high mortality rate is infection to the human papillomavirus (HPV). The aim of the present study was to investigate the effect of silencing HPV E6 oncogene on cervical cancer cells using specific siRNAs.
Materials and Methods: CaSki cervical cancer cells, carrying E6 gene, were cultured and then transfected with E6 targeting siRNAs. The cell viability through suppression of E6 expression was explored using MTT assay. Besides, apoptosis induction was investigated by means of flow cytometry using Annexin / PI staining. The changes in the expression of target genes were examined via  Real-Time PCR.
Results: E6 gene silencing caused a significant decrease in the survival rate of CaSki cells through remarkable enhancement of apoptosis induction. Moreover, E6 suppression led to significant upregulation of P53, Bax, Caspase-3, and Caspase-9 mRNA expression while downregulated Bcl-2 expression. Interestingly, it was found that suppression of E6 expression could lead to upregulation of  E5 and E7 expression as a compensatory mechanism for E6 deactivation.
Conclusion: According to the results of this study, suppression of E6 expression using specific siRNAs could be considered as a therapeutic approach for cervical cancer.