Abstract
Purpose::
Bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF), has shown promising preclinical and clinical activity against various cancers. The aim of this study is to evaluate the inhibitory effect of bevacizumab on an angiogenesis model in co-culture with Rb cells in vitro and a retinoblastoma xenograft model in vivo.
Methods::
Y 79 human retinoblastoma cells, human umbilical vein endothelial cells (HUVEC) and its co-culture cells were treated with 0.01 mg/mL, 0.02 mg/mL and 0.04mg/mL of bevacizumab for 3 days. Cell viability and VEGF in the media were measured using CyQUANT® NF cell proliferation assay kit and ELISA kit. To test whether bevacizumab may inhibit the growth of tumor in retinoblastoma xenograft model, 40 athymic nude mice (4-6 weeks old) were injected subcutaneously with 1 X 107 Y 79 cells. Five days after tumor injection, the mice were randomized to 4 groups of 10 mice each. The each group received 0.2 mL of intraperitoneal injection twice a week; 10 µg, 50 µg and 100 µg of bevacizumab respectively and PBS. Injections were continued for 4 weeks, during which tumor size was individually measured. The mice were then killed and the weight of each tumor was determined.
Results::
Bevacizumab had no significant effect on the viability or the growth of both Y 79 cells and HUVECs. The growth of HUVECs in co-culture with Y 79 cells was increased to 156±1 % compared to that of HUVECs monoculture, which corresponds with increased VEGF in co-culture. This increased HUVECs proliferation was suppressed to 58 ± 5 % by complete blockage of VEGF with bevacizumab treatment. Mice treated with bevacizumab showed significantly smaller final tumor size; 515 mm3, 542 mm3 and 608 mm3 in 100 µg, 50 µg and 10 µg of bevacizumab treated groups than in the control group (833 mm3) in dose dependent manner. (P<0.05) The final tumor weights; 0.25±0.17g, 0.18±0.15g, 0.21±0.12g in 100µg, 50µg and 10µg of bevacizumab treated groups were also significantly smaller than in the control group,0.55±0.55 g.(P<0.05)
Conclusions::
Treatment with bevacizumab, anti-VEGF monoclonal Ab, inhibited the growth of HUVECs in co-culture with Y79 cells in vitro and suppressed the growth of tumor in retinoblastoma xenograft model in vivo.
Keywords: retinoblastoma • tumors