Effects of all-trans retinoic acid combined with gamma radiation on proliferation and apoptosis of esophageal carcinoma TE13 cells / 肿瘤

ABSTRACT

Objective: To investigate the effects of ATRA (all-trans-retinoicacid) combined with gamma radiation on proliferation and apoptosis of human esophageal carcinoma TE13 cells, and to explore the possible mechanism. Methods: The effect of ATRA on the proliferation of TE13 cells was detected by MTT method. When the cell growth RI (inhibitory rate) reached levels of 25%, 50% and 75%, the TE13 cells were treated with the corresponding inhibitory doses of ATRA combined with 4 Gy gamma radiation. The effects of this combination intervention on cell cycle distribution and apoptosis of TE13 cells were detected by FCM (flow cytometry). The colony-formation ability and cell viability were detected using colony-formation experiment. The expression of cyclinD1 protein was detected by FCM. Results: The inhibitory effect of ATRA on the proliferation of TE13 cells was significant in a dose- and time-dependent manner. The cell growth IRs reached 22.0%, 55.1% and 71.1% at ATRA concentrations of 0.78, 6.25 and 12.5 μmol/L, respectively. The cell viability and colony-formation efficiency were significantly decreased in TE13 cells treated with ATRA in combination with 4 Gy gamma radiation, as compared with TE13 cells receiving administration of ATRA alone. The proliferative ability of TE13 cells was significantly reduced after ATRA treatment in combination with 4 Gy gamma radiation for 24 and 48 h; furthermore, the percentage of the cells arrested at phase G0/G 1 was increased accompanying with a significantly elevated apoptotic rate. Although the combination treatment (0.78 μmol/L ATRA and gamma radiation) had a weak influence on the expression of cyclinD1 protein, which was significantly decreased in other groups (6.25 and 12.5 μmol/L ATRA). Conclusion: ATRA exerts an inhibitory influence on the proliferation of TE13 cells through down-regulating cyclinD1 expression, arresting the cells at phase G0/G1, and inducing apoptosis. A higher-concentration of ATRA combined with gamma radiation can significantly decrease the expression of cyclinD1, promote G0/G1 cell cycle arrest, accelerate apoptosis, and limit the colony formation, but a lower concentration of ATRA combined with gamma radiation exerts a little influence on cyclinD1 expression, although it may accelerate apoptosis and limit the colony-formation at some periods of time after treatment. Copyright © 2012 by TUMOR.