Combination of Aloe-Emodin with Radiation Enhances Radiation Effects and Improves Differentiation in Human Cervical Cancer Cells

The aim of the present study was to investigate the effects of aloe-emodin (AE) on the radiosensitivity and differentiation of HeLa human cervical cancer cells. Cell proliferation was assessed in the HeLa cervical cancer cell line by a methylthiazolyldiphenyl-tetrazolium bromide assay. Radiosensitivity was determined by a colony-forming assay. Flow cytometry was used for analysis of cell cycle distribution and apoptosis. The expression of gamma-H2AX and Gyclin B was assessed by western blotting. Alkaline phosphatase (ALP) activity was measured by an ALP activity kit. It was demonstrated that AE inhibited the proliferation of HeLa cells in a concentration- and time-dependent manner, induced G(2)/M and S phase cell cycle arrest and enhanced the radiosensitivity of HeLa cells. The combination of AE and radiation induced apoptosis, upregulated cyclin B and gamma-H2AX expression and further improved ALP activity compared with treatment with AE or radiation alone. AE enhanced the radiosensitivity of HeLa human cervical cancer cells in vitro, inhibited the proliferation of HeLa cells, induced G(2)/M phase cell cycle arrest and, in combination with radiation, induced the apoptosis and improved the differentiation of HeLa cells.