Effects Of Silencing Livin Gene By RNA Interference Carried By Lentiviral Vector On Tumor Growth And Apoptosis In Nude Mice

BackgroundLung cancer is one of the most common malignancies worldwide ,Recent studies have suggested that Livin is highly expressed in lung cancer. It may be involved in tumorigenesis and development of lung cancer.In this study,we used RNA interference technology to silence Livin expression,then observed the effects of the proliferation of adenocarcinoma of lung cell SPC-A1, and then we established the tumor-bearing nude mice model of SPC-A-1, explored the possible mechanism in vivo.Objective:To inhibit the livin gene expression in nude mice by livin shRNA carried by lentiviral vector and to observe its effect in tumor growth and apoptosis in transplantation tumor of lung adenocarcinoma.Methods:SPC-A-1 was injected into nude mice to form subcutaneous lung adenocarcinoma model. All the nude mice were randomly divided into three groups according to tumor size the eighth day after inoculation:the blank group;the negative group;the experimental group. Different interventions were given for different groups in four consecutive days.①Experimental group:lentivirus-delivered livin shRNA were injected into tumo(r2×106TU,5ui)②Negative group:non-transfected lentivirus vectors were injected into tumor(2×106TU,5ul)③Blank group:NS were injected into tumor(5ul). The tumor growth was observed at the same time. The volume and weight of these tumors was measured in different time points. The curve of tumor growth was then described by SPSS18.0 software, and the inhibition rate was calculated The tumor growth was observed at the same time. The volume and weight of these tumors was measured in different time points ; The expression of livin were detected by western-blot. Apoptosis was evaluated by terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling assay. Then the cell apoptosis and cell cycle were detected according to the manual instruction of Annexin V-fluorescein isothiocyanate / Propidium Iodide (Annexin V-FITC/PI) .Cell proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromideResults:The study showed that livin gene expression was successfully silenced after the transplantation models were injected with lentivirus-delivered livin shRNA. The tumor growth and a lighter tumor weight in experimental group than the blank and negative control groups (P<0.01) Further more, higher levels of cell apoptosis were measured by flow cytometry analysis and tunnel analysis, but lower levels of cell proliferation were detected by MTT in the experiment group(KD) with Livin expression silenced than that in controls (P<0.01). After livin gene expression was knocked down, cell cycle was arrested in G0/G1 phase. The results suggest that Livin may promote the development of tumor through regulating cell cycle progression and thus livin maybe a potent target for cancer treatment.Conclusions:The lentivirus-delivered livinshRNA can inhibite the proliferation of transplantation tumor of lung carcinoma effectively, and livin may promote the development of tumor through regulating cell cycle progression and thus Livin maybe a potent target for cancer treatment.