Rhein lysinate induced S-phase arrest and increased the anti-tumor activity of 5-FU in HeLa cells.

Rhein lysinate (RHL), easily dissolved in water, is one of the anthraquinones, and has been shown to have anti-tumor activity in different human cancer cell lines. In the present study, we observed that RHL could cause vacuolar degeneration in HeLa cells, which was not observed in human umbilical vein endothelial cells (HUVECs) and other cell lines (SKOV-3 and SK-BR-3). Therefore, the purpose of this study was to investigate the anti-tumor effect of rhein lysinate on human cervix cancer HeLa cells. The results indicated that RHL could induce HeLa cell S-phase arrest and RHL (higher than 80 μM) also induced HeLa cell G2/M-phase arrest in a dose-dependent manner. Compared to the HeLa cells, RHL induced HUVECs G1-phase arrest at all dose levels tested in a dose-dependent manner. Treatment with RHL led to a significant S or G2/M-phase arrest through promoting the expression of p53 and p21 and the phosphorylation of p53. Moreover, 80 μM RHL could increase 5-FU anti-tumor activity. In conclusion, RHL could be a novel chemotherapeutic drug candidate for the treatment of human cervix cancer in the future.