The Effect Of HPV 16 E7-targeting SiRNA On Tumor Suppressor Genes, Cell Proliferation And Apoptosis

Background Persistent infection with high-risk genotypes of human papilloma viruses (HPVs) is the necessary cause for malignant transformation of infected cells in related carcinomas. More than 50% of HPV-associated carcinomas are infected with HPV 16, E6/E7 oncoprotein of which acts as the key role. E6/p53-E7/pRB pathway had been confirmed already to be one of important carcinogenic mechanisms. However, more and more data showed that other pathways could be involved into the HPV 16-associated carcinomas. By use of HPV 16-positive cell lines and clinical samples, scientists found the expression of six genes (MT1G, NMES1, RRAD, FRP1, SPARC, TFPI2) was significantly down-regulated at mRNA level, and the six genes acted as tumor suppressors in malignancy. We speculate that HPV 16 E7 is involved into the down-regulation of these six tumor suppressors. RNA interfering technology was applied to prove our hypothesis. Also, cellular proliferation and apoptosis were studied during the experimental process.Objective To explore the effect of HPV 16 E7 siRNA upon six tumor suppressor genes (MT1G、NMES1、 RRAD、 SFRP1 SPARC、 TFPI2), cell proliferation and apoptosis.Methods SiHa cell was transfected with small interfering RNA (SiRNA) targeting HPV 16 E7 for 48 hours. Then E7 and six tumor suppressor genes were detected by qPCR at mRNA level. Also, cell proliferation and apoptosis were investigated by CCK-8 and flow cytometric analysis, respectively.Results In E7-targeting siRNA transfection group, the mRNA of E7 and 6 tumor suppressor genes was down-regulated (P< 0.05) and up-regualted (P< 0.05 for each gene), respectively. No significant difference of tested mRNA was observed between negative and blank control. The cellular proliferation of E7-targeting siRNA transfection group decreased approximately 45% with significant change compared with negative and blank control (P< 0.05). Also, the frequency of apoptotic cell in E7-targeting siRNA transfection group was 9.222% with significant increase compared with negative and blank control (P< 0.05).Conclusion Our founding suggests that HPV 16 E7 is possibly involved in cellular malignant transformation via influencing the expression of six tumor suppressor genes.