OBJECTIVETo establish an implanted model of human colonic carcinoma on chick embryo, and to study the effects of anti-angiopoietin-2 antibody on its vascularization.

METHODSThe human colonic adenocarcinoma cell line HT-29 was transplanted on the chick embryo's chorioallantoic membrane(CAM), and the angiogenesis characteristics were observed by stero-microscope, light microscope and immunohistochemistry. Furthermore, the effects of anti-angiopoietin-2 antibody on angiogenesis and tumor growth were also investigated.

RESULTSThree to seven days after HT-29 cell line was implanted into CAM, tumors grew rapidly and new blood vessels grew toward tumors. Five days after anti-angiopoietin-2 antibody was given, the number of blood vessels in anti-angiopoietin-2 antibody group was significantly down-regulated than that in tumor control group observed by stero-microscope (37.2+/-4.6 vs 56.8+/-7.4, P<0.01), but was up-regulated than that in normal control group (37.2+/-4.6 vs 9.6+/-2.4, P<0.01). Microvessel density(MVD) in anti-angiopoietin-2 antibody group was much lower than that in tumor control group by histological examination (9.6+/-2.4 vs 20.2+/-5.8, P<0.01).

CONCLUSIONAngiopoietin-2 antibody is able to inhibit the angiogenesis induced by colorectal cancer cell line HT-29 obviously. The anti-angiopoietin-2 antibody may be potentially useful for clinical treatment of colonic carcinoma.