title: Antitumor effects of human ribonuclease inhibitor gene transfected on B16 melanoma cells.
abstract: Human ribonuclease inhibitor (RI) is a cytoplasmic acidic protein. The experiment demonstrated that it might effectively inhibit tumor-induced angiogenesis and inhibit tumor growth. Ribonuclease inhibitor is constructed almost entirely of leucine-rich repeats, which might be involved in unknown biological effects besides inhibiting RNase A and angiogenin activities. The exact molecular mechanism of antitumor on ribonuclease inhibitor remains unclear so far. In order to further understand the function of ribonuclease inhibitor and investigate the relationship with tumor growth, our study established a transfection of human ribonuclease inhibitor cDNA into the murine B16 cells by the retroviral packaging cell line PA317. The cell line transfected with a stably high expression of ribonuclease inhibitor was identified. We found that the transfected ribonuclease inhibitor could obviously inhibit cell proliferation, regulate cell cycle and induce cell apoptosis in vitro. Mice that were injected with the B16 cells transfected RI cDNA showed a significant inhibition of the tumor growth with lighter tumor weight, lower density of microvessels, longer latent periods, and survival time than those in the other two control groups. In conclusion, the results reveal the novel mechanism that antitumor effect of ribonuclease inhibitor is also associated with inducing apoptosis, regulating cell cycle and inhibiting proliferation besides antiangiogenesis. These results suggest that ribonuclease inhibitor might be a candidate of tumor suppressor gene in some tissues. RI could become a target gene for gene therapy. Our study may be of biological and clinical importance.
authors.affiliation: Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116027, Liaoning Province, China.
authors.forename: Jun-Xia
authors.initials: JX
authors.lastname: Chen
authors.forename: Ying
authors.initials: Y
authors.lastname: Gao
authors.forename: Ji-Wei
authors.initials: JW
authors.lastname: Liu
authors.forename: Yu-Xiang
authors.initials: YX
authors.lastname: Tian
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.forename: Xiu-Yun
authors.initials: XY
authors.lastname: Cui
mesh_terms: D020533:Angiogenesis Inhibitors / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3; D020169:Caspases / Q000096:biosynthesis; D006801:Humans; D008546:Melanoma, Experimental / Q000188:drug therapy / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D010926:Placental Hormones / Q000235:genetics* / Q000494:pharmacology* / Q000627:therapeutic use; D014162:Transfection
chemical_list: D020533:Angiogenesis Inhibitors; D010926:Placental Hormones; C022052:placental ribonuclease inhibitor; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases