Anti-angiogenic effect of silymarin on colon cancer LoVo cell line

Objective. This study was designed to evaluate the anti-angiogenic effect of silymarin (SM) and its major pure component silibinin (SB), and also thalidomide (TH). Materials and methods. A modified in vitro system using a coculture of endothelial (EA.hy 926) and colon cancer (LoVo) cell lines was adopted in this study. Results. In cytotoxicity assay, SM/SB/TH concentrations causing 20% (IC20) inhibition of cellular growth were 41.8 mug/ml/0.22 mM/0.088 mM for EA.hy 926 cells, and 16.1 mug/ml/0.12 mM/0.099 mM for LoVo cells, respectively. All 3 drugs showed concentration dependent inhibition of migration and differentiation assay. The IC50 inhibiting chemotaxis migration of EA.hy 926 towards LoVo by SM/SB/TH was 1.15 mug/ml/0.66 muM/1.98 muM, respectively. In differentiation assay, SM/SB/TH inhibited in vitro capillary tube formation by 50% at 1.25 mug/ml/2.6 muM/6.3 muM, respectively. In an analysis of vascular endothelial growth factor secreted by LoVo cells, SM/SB/TH decreased 50% secretion at 6.52 mug/ml/6.6 muM/131.7 muM, respectively. Conclusion. SM/SB has a strong anti-angiogenesis effect on the colon cancer cell line, and this might provide an alternative treatment option for anticancer treatment. (C) 2003 Elsevier Inc. All rights reserved.