Antitumor activity of rhein lysinate against human glioma U87 cells in vitro and in vivo

In previous studies, we demonstrated that rhein lysinate (RHL), the salt of rhein and lysine that is easily dissolved in water, inhibited the growth of tumor cells derived from breast and ovarian cancer, hepatocellular carcinoma, cervical cancer and lung carcinoma. Based on these observations, human glioma U87 cells and a xenograft model in BALB/c nude mice were used to examine the antitumor activity of RHL against human glioma. Notably, RHL statistically significantly suppressed the growth of human glioma U87 xenografts in BALB/c nude mice. In vitro, there was a significant reduction in cell proliferation after treatment with RHL in a dose- and time-dependent manner. The overall growth inhibition was correlated with the increase in reactive oxygen species (ROS) production and cell apoptosis. The apoptosis- and cell cycle-related proteins including BAX and Bim were increased, whereas Bcl-2 and cyclin D were decreased in the RHL-treated cells. The results demonstrated that RHL is highly effective against the growth of human glioma U87 xenografts in BALB/c nude mice. The potent antitumor activity of RHL may be mediated through downregulation of Bcl-2 and cyclin D expression and upregulation of BAX and Bim expression.