The Inhibitory And Chemosensitivity Of PTEN Adenovirus For Lung Cancer And Its Mechanism

Objective:To explore the inhibitory and chemosensitivity of recombinant adenovirus PTEN( phosphatase and tensin homologue deleted chromatosome10)on lung cancer and its possible mechanisms.Methods:Recombinant adenovirus Ad-PTEN was constructed and transfected into the human embryonic kidney 293 (QBI-293A) cells. The adenovirus completed the amplification in QBI-293A cells and the titration was also detected. The human pulmonary carcinoma cell line NCI-H446 was infected by Ad-PTEN and combined with cisplatin (DDP) in vitro, and were randomly divided into five groups: PBS negative control group(PBS group), idling adenovirus group(Ad group), adenovirus-mediated PTEN group (Ad-PTEN group), DDP positive control group(DDP group) and Ad-PTEN combined with DDP (referred to as joint group). The expression of PTEN in NCI-H446 small cell lung cancer cells was detected by western blotting. The effect of enhanced growth-suppressing and apoptosis-inducing by Ad-PTEN on NCI-H446 small cell lung cancer cells were analyzed by MTT assay and Flow cytometry. The expression of apoptosis-related genes (P53,Bax,Caspase-3,Bcl-2,Survivin) was detected by reverse transcription-PCR (RT-PCR). The human lung cancer mode was established with NCI-H446 cells in athymic nude mouse. Mice of the groups were progressed multi-points injection in tumor, dose of each injection: PBS group: 50μl PBS/only; Ad Group: 50μl 1x107pfu Ad/only; Ad-PTEN Group: 50μl 1x107pfu Ad-PTEN/only; DDP group of drug concentration 2mg/kg, Ad-PTEN+DDP Group: 50μl 1x107pfu Ad-PTEN/only+DDP 1mg/kg. Next day once, a total of 6 injections. The gross tumor volumes were measured dynamically. The ratios of tumor-suppression were calculated. The tumors were observed by HE staining method. Immunohistochemistry for the detection of small cell lung cancer NCI-H446 tumor growth-related factor expression: (1) Caspase3, Bax and other pro-apoptotic factor; (2) Bcl-2, Survivin and other apoptosis inhibitory factor; (3) VEGF and other angiogenesis-related factors.Results:After the amplification of Ad-PTEN in QBI-293A cells, the titration was 108pfu/mL. The expressions of PTEN in NCI-H446 cells were detected by western blotting. Adenovirus-mediated PTEN significantly inhibited NCI-H446 cell growth, induced cell apoptosis, and retarded NCI-H446 human lung cell transplanted tumor growth in athymic nude mouse, exhibiting anti-tumor effect. Furthermore, Ad-PTEN significantly enhanced the chemosensitivity to anticancer drug DDP in lung cancer in vitro and vivo. Ad-PTEN group, DDP group, Ad-PTEN+DDP group of NCI-H446 cells in the P53, Bax, and Caspase-3 expression was significantly increased, while Bcl-2 and Survivin gene expression was significantly reduced; and Ad-PTEN+DDP Group effect than Ad-PTEN group, DDP group is more significant. Is the Ad-PTEN with anti-tumor effect of some molecular biological mechanisms.Conclusion:1. Ad-PTEN had significant effect in suppressing cell growth and inducing cell apoptosis in NCI-H446 small cell lung cell and small cell lung cancer transplanted tumor growth in athymic nude mouse.2. Ad-PTEN enhanced chemosensitivity to DDP effect in suppressing cell growth and inducing cell apoptosis in NCI-H446 small cell lung cell and small cell lung cancer transplanted tumor growth in athymic nude mouse.3. Ad-PTEN+DDP had more potent effect in up-regulating the expression of P53,Caspase3,Bax and down-regulating the expression of Bcl-2,Survivin, which may be responsible for its anti-tumor effect on NCI-H446 small cell lung cell in vitro and in vivo in athymic nude mouse model.4. Ad-PTEN, DDP and Ad-PTEN+DDP had effect in down-regulating the expression of angiogenesis-related factors VEGF, Ad-PTEN+DDP compared with Ad-PTEN, DDP more significantly, which may be another important mechanism involved in its synergetic effect in suppressing lung cancer transplanted tumor growth in athymic nude mouse model.