The Experimental Study On The Flavopiridol Effects Of The Esophageal ECa-9706Cell Lines Radiosensitive Mechanism

Radiation therapy is one of the main methods of treatment of esophageal cancer.Although in recent years, radiotherapy technology has made rapid progress insignificantly improved the accuracy of tumor treatment, but the ultimate efficacy is notsatisfactory. Therefore, how to improve the efficacy of the treatment of esophagealcarcinoma has become the current problems to be solved.Flavopiridol is a small molecule Cyclin-dependent protein kinases (CDKs)inhibitors, the chemical structure of Flavonoids, originally came from an Indian plant, isthe first clinical trials confirmed CDKs inhibitors on a variety of tumors，founed itcan inhibite prostate cancer, esophageal cancer and so on strongly,which significantlypossible anti-tumor mechanism of inhibition of CDKs activity, inducing cell apoptosisand anti-antigenic, and quiescent cells and proliferation of cells with similar anti-tumoreffect. In addition, Flavopiridol inhibition after radiotherapy of DNA damage repairprocess, improve the sensitivity of cells to radiation therapy. By previous experimentaldetermination of Flavopiridol on ECa-9706cell line IC50(LD50)256nmol/L, andprove that the ECa-9706cell lines with radiation to read sensitive role,51.2nmol/L(that is1/5IC50) the Flavopiridol the SER (radiation to read sensitive ratio) of1.268.But the molecular mechanisms of radiation Zeng Min, esophageal ECa-9706cell linesis still unclear. The study found that VEGF, Survivin, CyclinD1proteins in the people avariety of tumor cells have abnormal expression. In this study, by the combined effectof Flavopiridol and radiation in the ECa-9706cell lines, and the ECa-9706cell cyclechanges of esophageal cancer before and after the experiment, as well as VEGF,CyclinD1and Survivin protein expression level, to analyse the sensitivity radiationmechanismof Flavopiridol with ECa-9706cells of esophageal cancer,which provide the basis of the therapy of esophageal cancer in clinical applicationObjective:Flavopiridol and radiation alone or in combination with the ECa-9706cell lines of the esophageal cancer, according to the changes of cell cycle before andafer treament as well as VEGF, CyclinD1and Survivin in the level, to analyse thesensitivity radiation mechanismof Flavopiridol with ECa-9706cells of esophagealcancer.Methods:The experiment was divided into four groups (control group: notreatment; drug group:0.2x the IC50Flavopiridol; radiation group:6Gy absorbeddose-ray irradiation; experimental group:0.2x the IC50Flavopiridol treatment after24hours6Gy single absorbed doseray irradiation), Detection Flavopiridol and radiationalone and combined effects of ECa-9706cell lines after cell cycle distribution by flowcytometry. Detection Flavopiridol and radiation alone or in combination of VEGF,CyclinD1, and survivin protein expression level changes in esophageal ECa-9706celllines by Western blotting.Results:1.The G0/G1and G2/M phase ratio of experimental group weresignificantly higher than those in control group,which have statistically significantdifference(P<0.05); The S phase ratio of experimental group were significantly lowerthan those in control group,which have statistically significant difference(P<0.05); TheG0/G1phase ratio of drug group were significantly higher than those in controlgroup,which have statistically significant difference(P<0.05); The S phase ratio ofexperimental group were significantly lower than those in drug group and radiationgroup,but the G2/M phase ratio were significantly higher, which both have statisticallysignificant difference(P<0.05).2.By the Western blotting inspect Eca-9706cell lines of esophageal cancer indifferent groups, of which VEGF, Survivin, CyclinD1protein expression of thehorizontal bar with the gray-scale analysis shows that there are VEGF,Survivin, CyclinD1expression in four–groups。The level of VEGF、Survivin、CyclinD1expressed inexperimental group were decreaser than control group(P <0.05); The level of VEGF、Survivin、CyclinD1expressed in experimental group were lower than drug group (P<0.05),so were lower than the radiation group（P<0.05）Conclusion:1. Flavopiridol with radiation in Eca-9706cell line of esophagealcancer, which enable the ECa-9706cell cycle arrest in the radiosensitive G0/G1phaseand G2/M phase, reduce the radiation tolerance of the S phase proportion. 2. The synergy of Flavopiridol and radiation can reduce the level of VEGF andSurvivin, CyclinD1protein expression of line Eca-9706of esophageal cancer,whichinfered that Flavopiridol can arrest cell cycle in the G0/G1phase and G2/M phase ofradiosensitive by reducing the level of CyclinD1expressed, reduce the expression ofapoptosis inhibiting protein, and weak the radiative inhibitor of Eca-9706cells ofesophageal cancer,and achieve ultimately the radiosensitizing effect to the lineEca-9706cell line of esophageal cancer.