RESUMO
Background and purpose: It has been reported that activation of Notch1 could strongly inhibit proliferation of HPV (human papilloma virus)-positive HeLa cells by down-regulation of the E6 and E7 genes. The aim of this paper was to investigate the role of the Notch signaling pathway in growth arrest of EC109 cells in vitro and the molecular mechanism. Methods: EC109 cell lines, a well differentiated human ESCC (esophageal squamous cell carcinoma) cell line with HPV18-positive, was used in the study. Exogenous intracellular domain of Notch1(ICN) was transfected into cultured EC109 cells by lipofectamine transfection, the proliferation of the transfected cells was measured by an MTT assay. Cell cycle distribution was analyzed by flow cytometry. Human papilloma virus type 18 (HPV18) E6/E7 mRNA expression was detected by RT-PCR, and p53 protein expression was detected by Western blot.Results: Activation of Notchl signaling resulted in inhibition of EC109 cell proliferation with the induction of G_2/ M arrest. There was a significant difference in terms of the percentage of G_2/M phase cells among the ICN-transfected group (42.57±1.57)% and the non-transfected group (1.88±0.66)% or the empty plasmid transfected group (1.99±1.02)% (P<0.01). Down modulation of HPV18 E6/E7 gene expression and upregulation of p53 expression was (2.15±0.23) in ICN-transfected group higher than non- transfected group (0.45±0.07) and empty plasmid transfected group (0.46±0.02) (P<0.01). Conclusion: Repression of HPV18 E6/E7 expression by Notch1 signaling results in growth suppression of HPV18-positive EC109 cells with concomitant activation of p53-mediated pathways.
RESUMO
Objective In order to study the pathogenesis of human papillomavirus(HPV) and seek for a therapeutic approach of the diseases caused by HPV, the construction of HPV18 E6E7 antisense RNA expressing recombinants was studied. Methods We amplified the HPV18 E6E7 816bp by PCR with HPV18 plasmid DNA as the template. pLNSX retroviruses were used as vectors,the HPV18 E6E7 retrovirus recombinants were constructed. And then the recombinants were cleaved with restriction endonuclease and hybridized with Southern blot for identifying the inserting direction and special check respectively. Results and conclusion The HPV18 E6E7 antisense RNA retrovirus expressing recombinants were screened and obtained,which had laid the foundation of studying the function of E6E7 genes further and explore whether the antisense technique can adjust and control the expression of E6E7 genes.