Objective   To construct an eukaryotic expression vector encoding human papilloma virus E7

and investigate the effect of E7 overexpression on the proliferation and invasion of human epithelial carcinoma cell line A431.    Methods   After total RNA from Caski cells was obtained by Tripurer

cDNA was amplified by RT-PCR and then cloned into pEGFP-N1 vector using gene engineering technology. Recombinant expression vector pEGFP-E7 was confirmed by restriction digestion and sequencing

and then tran

sfected into A431 cells by liposome. Expression of E7 protein was detected by Western blotting. WST-1 assay and Transwell system were used to observe the growth and invasion of A431 cells. Cell cycle was measured by flow cytometry

and the expression of TGF-β in the supernatant was measured by ELISA.    Results   The recombinant expression vector pEGFP-E7 was successfully constructed. Western blotting indicated that E7 protein was overexpressed in A431 cells. Overexpression of E7 significantly increased cell proliferation and invasion. Flow cytometry showed there were more cells arresting in S phase and lesser in G

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phase. Overexpression of E7 significantly improved the secretion of TGF-β in A431 cells.    Conclusion   Overexpression of E7 enhances tumor cell proliferation and invasion

although TGF-β secretion is increased at the same time.