The Radiosensitivity Of Celecoxib On Human Breast Cancer By Blocking PI3K/Akt Signal Pathway

Objective:Celecoxib has obvious radiotherapy sensitization effect on human tumor, but the mechanism of radiotherapy sensitization effect is not understood. The purpose of the present experiment is to investigate the effect of Celecoxib on the radiosensitivity of human breast cancer cell.Methods:MDA-MB-231 cells were cultured in vitro. Thiazolyl blue(MTT) colorimetric assay was used to measure the inhibition of breast cancer MDA-MB-231 cell survival by different concentrations of celecoxib (10μmol/L,20μmol/L,30μmol/L,40μmol/L,50μmol/L,60μmol/L), Calculated IC₂₀, IC₅₀, selected IC20 drug concentration as the concentration of the follow-up experiment. Flow Cytometry(FCM) colorimetric assay was used to measure the cell cycle of breast cancer MDA-MB-231 by different concentrations of celecoxib (0μmol/L,20μmol/L,40μmol/L,60μmol/L). The MDA-MB-231 cell line in logarithmic phase measured radiosensitivity, which was divided into four groups: control group: without Celecoxib and radiation interference. drug group: Celecoxib exposed to MDA-MB-231 cell. radiation group: X-ray exposed to MDA-MB-231 cell. The case group: After Celecoxib exposed to MDA-MB-231 cell, X-ray was given. The apoptosis rate was analysed by Flow Cytometry(FCM). The radiotherapy sensitization effect was detected by Clone Formation Experiment, and calculated the survival fraction, cell survival curves drawn. Akt, pAkt and COX-2 protein expression were detected by Western blot method, as of Celecoxib on the MDA-MB-231 cells in the mechanism of radiosensitization.Results:1. The effect of the dose-dpendent growth inhibition was observed by the MTT analysis in human breast MDA-MB-231 cell line. And the IC50 and IC20 were (50.14±2.42)μmol/L, (20.21±1.34)μmol/L respectively.2 The Flow Cytometry showed that Celeeoxib could induce G1/G0 Phase arrest(P<0.05), and the reduction of S phase were significantly decreased in the group(P<0.05), and G2/M phase was no significant difference(P>0.05).3 Both Celecoxib and radiation induced MDA-MB-231 cells apoptosis. Apoptosis rate of case group was significantly higher than radiation group, at (31.20±1.27)% and (17.99±1.01)%, respectively(P<0.05).4 Clone Formation Experiment showed that the values of Dq, Do, SF2 in case group were significantly decreased compared with those in radiation group. SERDo was at 1.277 according to the clonogenic assay.5 Western blot assay showed that Celecoxib inhibited pAkt expression, whereas radiation increased the pAkt expression, but both Celecoxib and radiation in case group significantly inhibited the pAkt expression. Celecoxib inhibited COX-2 expression, whereas radiation increased the COX-2 expression, but both Celecoxib and radiation in case group significantly inhibited the COX-2 expression.Conclusion:1 Celecoxib obviously has a radiotherapy sensitization effect on human breast cancer MDA-MB-231 cell.2 Celecoxib can enhance the radiosensitivity of human breast cancer by blocking the activation of PI3K/Akt signaling pathway to increase radiosensitivity of breast cancer.