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 μg/ml/0.22 mM/0.088 mM for EA.hy 926 cells, and 16.1 μg/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 μg/ml/0.66 μM/1.98 μM, respectively. In differentiation assay, SM/SB/ TH inhibited in vitro capillary tube formation by 50% at 1.25 μg/ml/2.6 μM/6.3 μM, respectively. In an analysis of vascular endothelial growth factor secreted by LoVo cells, SM/SB/TH decreased 50% secretion at 6.52 μg/ml/6.6 μM/131.7 μM, 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 anti-cancer treatment.