The Potentiation Of Radiosensitivity By Cell Cycle Regulators In Cancer Cell Lines And Its Mechanisms

According to the statistic data reported by Chinese Ministry of Public Health, Tumor, which replaced of cardiovascular disease and cerebrovascular disease, has been the first factor of death in the city of China in Augst 2000. In china, more than 70% of patients with tumor were carried on radiotherapy, but radiotherapy failed to show satisfactory antitumor effects in human. The average cure rate by radiotherapy was < 40%. One of the most promising and intense research field of cancer radiotherapy research focus on the discovery of agents that enhance radiosensitivity.Tet is an alkaloid isolated from stephania tetrandra, which has the effects of expanding blood vessel, anti-inflammation, anti-fibrosis. Recently research reported that Tet can potentiate the anti-tumor effect of y -ray on lung cancer cells and leukemia cells. Staurosporine (STP), originally isolated from the culture broth of streptomyces, is a potent protein kinase antagonist that exhibits cytotoxicity toward cancer cells. In this study, we investigate the mechanisms and potentiations of radiosencetivity on cancer cells by Tet and STP.1. Potentiation of radiosensitivity by Tetrandrine in human tumor cells and its mechanismClonogenic (colony-forming) assay showed that the effect of Tet on tumor cells was in dose-dependent manner. IC50 value of Tet was 0.80, 0.91 and 1.07 uM in MCF-7, MCF-7/ADR and HT-29 cells, respectively. We choose 0.1 μM Tet for our synergy experiments according to the reported data.The cytotoxicity of X-ray to human breast cancer and colon carcinoma cells...