Mechanism of Ursolic Acid-Mediated Inhibition of Proliferation in Vascular Endothelial Glioaytoma

Purpose: To investigate the effects of ursolic acid (UA) on expressions of ERK1, C-Jun, C-Myc and Cyclin D1 in Human Umbilical Vein Endothelial Cells (HUVEC), and to explore the mechanism of anticancer activity of UA on glioma. Methods: HUVEC was treated with UA (0, 31.5, 62.5, 125, 250, 500 μg/mL) for 24 h, and 125 μg/mL for 0, 12, 24, 48 h, respectively) and PD98059 in vitro. Real-time polymerase chain reaction (RT-PCR) was performed to measure the endogenous mRNA levels of ERK1, C-Jun, C-Myc, and Cyclin D1, and Western blotting was used to determine the expressions of ERK1, C-Jun, C-Myc, and Cyclin D1 proteins. Results: The results show that the mRNA levels of ERK1, C-Jun, C-Myc, and Cyclin D1 were downregulated, following treatment with UA (in a doseand time-dependent manner) and PD98059 (p < 0.05). In addition, the protein expressions of ERK1, C-Jun, C-Myc, and cyclin D1 were all significantly down-regulated, after treatment with UA (in a doseand time-dependent manner) and PD98059 (p < 0.05). Conclusion: The findings indicate that UA can significantly inhibit the generation of vascular endothelial cells of glioma by down-regulating the expressions of ERK1, C-Jun, C-Myc and Cyclin D1 of ERK signal transduction pathway.