Experimental inhibition of corneal neovascularization by endostatin gene transfection in vivo

Objective To investigate endostatin gene therapy of rat corneal neovascularization induced by acid cauterization. Methods pBlast-hEndostatin and pBlast-Mcs were identified by digestion with Nhe Ⅰand Sal Ⅰ, by PCR reaction, by sequence, and then by alignment of PCR products with the geneBank using NCBIBLAST software. They were then purified with QIAGEN Endofree plasmid maxi kit. Rat corneal neovascularization models were made with 75% AgNO 3 and 25% KNO 3 cauterization. The treatment method was subconjunctive injection of the pBlast-hEndostatin with the control of pBlast-Mcs. Results pBlast-hEndostatin was found to contain the human endostatin gene. The rat corneal neovascularization induced by acid cauterization was significantly suppressed after subconjunctive injection of the pBlast-hEndostatin with inhibition rates of 37%, 40.2%, and 42.8% respectively on the sixth, tenth, and fifteenth day. The inhibition rate for the density of corneal neovascularization was 40%. However, no inhibition effect on the length of the neovascularization and corneal inflammatory cells was observed. Corneal neovascularization areas were positively correlated with edema and corneal opacity.Conclusions The plasmid of pBlast-hEndostatin contained the human endostatin gene. The rat corneal neovascularization induced by acid cauterization can be partially inhibited by subconjunctive injection of the pBlast-hEndostatin mediated by liposomes. Endostatin produced by transfected fibroblast cells directly inhibits corneal neovascularization. This is not caused by inflammatory reaction inhibition.

Retroviral endostatin gene transfer inhibits human colon cancer cell growth in vivo

Objective To investigate the therapeutic effect of retroviral endostatin gene transfer on the human colon cancer cell line,LoVo.Methods A retroviral vector pLESSN expressing secretable endostatin was constructed and packaged with a titer of 8.2×10 5 CFU/ml. A LoVo cell line was subjected to retrovirus-mediated endostatin gene transfer. The proviral integration of endostatin was analyzed with PCR. The function of endostatin was tested by MTT assay in vitro and a mouse xenograft model in vivo.Results After transfection and superinfection,amphotropic retrovirus was collected,and transduction with amphotropic retroviruses resulted in endostatin proviral integration. The endostatin secreted by transduced LoVo cells markedly inhibited endothelial cell growth up to 67% ( P <0.001),compared with the control cells. The gene expression of endostatin in LoVo colon tumor cells significantly inhibited tumor growth in vivo. There was an 86% reduction in tumor size in the endostatin-transduced group,accompanied by a reduction in vessels,compared with the control group ( P <0.01). Conclusion Retroviruses can allow functional expression of the endostatin gene in human colon tumors,showing promise for an antitumor strategy using antiangiogenesis.