ABSTRACT
By using a yeast two-hybrid system,a yeast two-hybrid bait vector was constructed and identified for screening of the HPV18 E6-interacting proteins,and its effects on the growth of yeast cells and the activation of reporter genes were investigated.Total mRNA extracted from Hela cells was reversely transcribed into cDNA.Fragment of HPV18 E6 cDNA was amplified using RT-PCR and directly ligated to the pGBKT7 vector.The recombinant plasmid was confirmed by restriction endonuclease analysis and DNA sequencing.The recombinant pGBKT7-HPV18 E6 plasmid and empty pGBKT7 vector were transformed into the yeast cell AH109,respectively.After they were cultured respectively in YPDA liquid medium and nutrition-deficient culture medium,their toxicity and transcriptional activation were tested by both the phenotype assay and the color assay.The bait plasmid HPV18 E6 was successfully obtained.After being cultured in YPDA liquid medium for 16h,the A600 nm values of two yeast fluids were 0.98±0.03 and 0.99±0.02,respectively.The recombinant pGBKT7-HPV18 E6 plasmid and empty pGBKT7 vector could grow to white colonies on SD/-Trp/X-α-gal plates,while no colony could survive on SD/-His/-Trp/X-α-gal,SD/-Ade/-Trp/X-α-gal plates,indicating that the bait plasmid pGBKT7-HPV18 E6 was constructed successfully and expressed correctly,and could not activate the transcription of reporter gene alone.The yeast two-hybrid GAL4 system 3 can be utilized to find HPV18 E6 interacting proteins.
ABSTRACT
Objective To elucidates the effects of HPV18 E6 siRNA targeting at human papillomavirus(HPV)18 E6 gene on the proliferative activity of HeLa cells and chemotherapy sensitivity.Methods HPV18 E6 expression of HeLa cells was inhibited by siRNA interference,the change of P53 and P21 proteins expression level was measured by Western blot.MTT assay was used to detected proliferative activity and sensitivity to paclitaxel liposome of HeLa cells.Results After inhibition of E6 expression,P53 and P21 proteins increased and the growth of HeLa cells was decreased(P ＜0.01).The inhibition rate of HeLa was markedly increased after transfection of HPV18 E6 siRNA and paclitaxel liposome.Conclusion HPV18 E6 siRNA can effectively silence gene expression of E6 and inhibit proliferation of HeLa cells.HeLa cells are more sensitive to combine HPV18 E6 siRNA with paclitaxel liposome than that of control groups.
ABSTRACT
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.
ABSTRACT
To screen for novel binding proteins interacting with high-risk HPV 18 E6 oncogene, the strain AH109 was transformed with pGBKT7-HPV18 E6 plasmid, and subsequent transference was utilized to screen for interacting proteins with HPV 18 E6 in human Hela cDNA library. HPVl8 E6 mRNA was expressed in yeast and there was no self-activation and toxicity in AH109. Seven proteins that interacted with HPV18 E6, including transmembrane protein 87B, phosphonoformate im- muno-associated protein 5, vimentin, KM-HN-1 protein, dedicator of cytokinesis 7, vaccinia related kinase 2 and a hypothetical protein, were identified. It was suggested that yeast two-hybrid system is an efficient for screening interacting proteins. The high-risk HPV 18 E6 oncogene may interact with the proteins, which may be associated with signal transduction and transeriptional control, epithelial cell invasion and migration, as well as humoral and cellular immune etc. This investigation provides functional clues for further exploration of potential oncogenesis targets for cancer biotherapy.
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Objective To study the effect of small interfering RNA(siRNA) of human papillomavirus(HPV) 18(E6) gene on apoptosis of HPV-related cervical HeLa cell line.Methods siRNA targeting HPV18 E6 mRNA was designed and generated by PCR amplification.The PCR products containing U6 promoter and the siRNA sequence were then transfected into HeLa cells via Lipofectamine()~(TM)2000.Cell viability was determined by MTT assay.Apoptosis was detected by morphological observation and flow cytometry analysis.The expression level of HPV18 E6 mRNA was assayed by RT-PCR.Results The cell growth and viability of(siRNA) transfected group were significantly inhibited(P
ABSTRACT
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.