The effect of all-trans retinoic acid on the expressions of VEGF and VEGF receptors,and growth inhibition of human colon cancer Lovo cell line

Objective To investigate the effect of all-trans retinoic acid(ATRA) on the expressions of VEGF and its receptors,and growth inhibition of Lovo cells,and analyze its possible mechanisms.Methods Lovo cells were treated with ATRA at different concentrations for different times,and MTT assay was used to measure cell growth inhibition.The growth stimulation of exogenous recombinant human VEGF165 to Lovo cells and its inhibitory effect of ATRA were also examined.Cell cycle and apoptosis were evaluated by flow cytometry(FCM).The level of VEGF secreted by Lovo cells and expressions of VEGF receptors were measured using ELISA technique and flow cytometry respectively..Results ATRA greatly inhibited the proliferation of Lovo cells in dose-and time-dependent manners.Exogenous recombinant human VEGF165 stimulated Lovo cell growth and such growth stimulation was inhibited dose-dependently by ATRA.With the increasement of ATRA concentrtation,the proportion of cell cycle G0/G1 cells increased from(60.10±1.27)% to(84.80±1.40)%,and the apoptosis rate increased to(39.79±3.96)%.The level of VEGF secreted by Lovo cells and expressions of its receptors were decreased with ATRA treatment..Conclusions ATRA decreases the expressions of VEGF and its receptors,and inhibits tumor cell growth.The possible mechanisms may be involved in blockade of the paracrine and autocrine pathways of VEGF,acceleration of tumor cell apoptosis and blockade of cell cycle.