Inhibition of Growth and Metastasis of Tumor in Nude Mice after Intraperitoneal Injection of Bevacizumab.

Objective: To explore the inhibitory effect of bevacizumab, a vascular endothelial growth factor antibody, on angiogenesis in human osteosarcoma of nude mice.

Methods: Twenty-one nude mice were inoculated with red fluorescent protein (RFP)-labeled human osteosarcoma cell line 143B-RFP, that is, clones that expressed RFP in the cytoplasm, and randomly assigned to one of three groups: G1 (Control group, injected with saline solution); G2 (intraperitoneal bevacizumab 2 mg/kg twice per week) and G3 (intraperitoneal bevacizumab 5 mg/kg, twice per week). The tumor-bearing mice were examined in a fluorescence light box that was illuminated periodically. The primary tumors were measured by fluorescence imaging weekly and their volumes calculated.

Results: The mean tumor volumes were significantly smaller in the G3 (186.4 ± 100.8 mm(3) ) than the control group (587.0 ± 406.8 mm(3) ) (P < 0.05) on Day 31, and again significantly smaller in the G3 (677.3 ± 461.9 mm(3) ) than the control group (3162.6 ± 1529.2 mm(3) ) on Day 38 (P < 0.01). The average tumor volume in the G2 group was 493.5 ± 425.4 mm(3) on Day 31 and 1870.1 ± 1524.8 mm(3) on Day 38. The effect on tumor volume was greater in the G3 than the G2 group. Three mice in the G2 group, four in the G3 group and four in the control group developed lung metastases that were confirmed by pathological examination; these differences were not statistically significant (P < 0.05).

Conclusions: Bevacizumab exhibits strong antiangiogenesis activity in experimental osteosarcoma in a nude mouse model but does not influence the incidence of lung metastasis. Our findings may have considerable potential for the treatment of osteosarcoma.