Research Of Damage Efficiency By Livin/Survivin RNA Interference On Animal Models Of Colorectal Cancer Mediated By MPEGylated-chitosan Nanoparticles

Objective:to explore the gene expression of livin/survivin in the animal models of colorectal cancer and to study the damage efficiency by livin/survivin RNA interference on animal models of colorectal cancer mediated by mPEGylated -chitosan nanoparticles. So as to explore the feasibility of double gene interference for colorectal cancer.Methods:Animal models of colorectal cancer were made by injection of colorectal cancer cell HT-29 into the subcutaneus of BALB/C-nu rats. Subcellular localization of livin/survivin was analyzed by immunohistochemical technique. The tumor size was registered after the transfection of livin/survivin genes.livin and survivin gene expression respectively.Using HE staining to observe tumour tissue. Immunohistochemical SP to analyze livin and urvivin protein expression after sgenes interference, TUNEL apoptosis dyeing to observe tumor cell apoptosis.Results:After the injection of colorectal cancer cell HT-29 into the subcutaneus of BALB/C-nu rats, sensible tumour could be observed after 2 weeks, and spring up during the following 3 weeks. The HE staining results of tumor coincided with colorectal cancer cell HT-29.After immunohistochemistry,the totalpositive rate of Survivin was 81%, Subcellular localization of Survivin was mainly in the cytoplasma(48.5%) , cell nucleus (49.2%), cell membrane(2.3%),and there were no significantly differences in the expressions of cytoplasma and cell nucleus (P<0.05). The totalpositive rate of Livin was 76.9%(strong postive rate 23.2%, moderate positive rate12.7%,low postive rate 11.0%), Subcellular localization of Survivin was mainly in the cytoplasma(49.6%), cell nucleus (50.4%), and there were no significantly differences in theexpressions of cytoplasma and cell nucleus (P<0.01). livin/survivin RNA interference by mPEGylated-chitosan nanoparticles could result in significant inhibition of the tumor growth and significantly decreased the level of livin/survivin protein.Conclusion:The animal models of colorectal cancer which were made by injection of colorectal cancer cell HT-29 into the subcutaneus of BALB/C-nu rats were feasible.Both survivin and livin were observed in the animal models of colorectal cancer by immunohistochemical technique, livin and survivin double gene silence mediated by mPEG-CS nanoparticles can reduce Livin and Survivin protein expression. It also can induce cell apoptosis, and the function is stronger than livin or survivin gene interference single.