title: Anti-tumor effect of endostatin mediated by retroviral gene transfer in mice bearing renal cell carcinoma.
abstract: We investigated whether transfer of the gene encoding the angiogenesis inhibitor endostatin into the NIH/3T3 fibroblast cell line could inhibit renal tumor growth in vivo. NIH/3T3 cells were transduced with retroviral vectors containing the murine endostatin (ES) gene. SCID mice bearing CaKi-1 derived tumors were given a subcutaneous injection of either ES-transduced cells or control cells and were monitored for tumor growth. At the end of the in vivo experiment, the mean tumor volume of treated mice was 51.6 +/- 2.4 mm3, while the tumor volume of control was 234.5 +/- 14.8 mm3. Microvascular density was significantly decreased on treatment (control 9.79 vs. ES 2.53%, <0.001) accompanied by a 23-fold increase in intratumoral necrotic area and a 2.94-fold increase in the apoptotic index, determined by immunohistochemistry with anti-activated caspase-3. Apoptotic cells were found in foci enriched in infiltrating leukocytes. In conclusion, retroviral endostatin gene transfer led to secretion of functional endostatin that was sufficiently active to inhibit tumor angiogenesis and tumor growth. A second mechanism may also be implied in endostatin-dependent tumor regression, associated with tumor infiltration of leukocytes. Besides its antiangiogenic properties, endostatin may be a promising adjuvant to immunotherapy.
authors.affiliation: Division of Nephrology, Department of Medicine, Universidade Federal de São Paulo, SP, Brazil.
authors.forename: Enia Lúcia
authors.initials: EL
authors.lastname: Coutinho
authors.forename: Luciana Nogueira de Sousa
authors.initials: LN
authors.lastname: Andrade
authors.forename: Roger
authors.initials: R
authors.lastname: Chammas
authors.forename: Ligia
authors.initials: L
authors.lastname: Morganti
authors.forename: Nestor
authors.initials: N
authors.lastname: Schor
authors.forename: Maria Helena
authors.initials: MH
authors.lastname: Bellini
mesh_terms: D020533:Angiogenesis Inhibitors / Q000378:metabolism*; D000818:Animals; D000970:Antineoplastic Agents / Q000378:metabolism*; D017209:Apoptosis / Q000502:physiology; D002292:Carcinoma, Renal Cell / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D045744:Cell Line, Tumor; D043169:Endostatins / Q000235:genetics / Q000378:metabolism; D018014:Gene Transfer Techniques; D006801:Humans; D008297:Male; D051379:Mice; D016513:Mice, SCID; D041681:NIH 3T3 Cells; D009368:Neoplasm Transplantation; D012190:Retroviridae / Q000235:genetics / Q000378:metabolism; D014161:Transduction, Genetic; D014183:Transplantation, Heterologous
chemical_list: D020533:Angiogenesis Inhibitors; D000970:Antineoplastic Agents; D043169:Endostatins