Research On Radiosensitivity Of Nasopharyngeal Carcinoma Cell Cne1 In Vitro To Inhibitor Of PI3K/Akt Injection

[Objective]To evaluate the radiosensitivity caused by LY294002 On nasopharyngeal carcinoma cell line CNE1 and investigate the possible sensitization mechanism of LY294002.It will provide the basis of exploring the target of nasopharyngeal carcinoma radiotherapy sensitization.[Materials and Methods]1.The experiment was divided into control(A)group,simpledrug(B)goup,simple radiation(C)group and radiation plus drug(D)group.The cell survival curves were determined by cloning assay and cell clone technique for evaluating the cell lethal effects and by multitarget one-lit model and L-Q model.2.The cell cycles and cell apoptosis rates were analyzed by using FCM(Flow cytometry)in the different groups which were given single dose 2Gy radiation.3.The Bad,Ku-70,Ku80mRNA were detected by RT-PCR method,and The expression of pAkt and total Bad were detected by western blot. 4.Statistical analysis was done with SPSS l2.0 and SigmaPlot11.0 software.The data Was expressed as meanl+SD,comparison among groups Was performed by One-Way ANOVA , t-test and pearson linear correlation.Significance Was accepted when p<0.05. [Results]1.Experiment result of radiosensitvity indicated that the abmty of cell line CNE1 forming colony in the testting group degraded contrasting with A group.With the increasing ofradiation dose,forming colony ability decreased obviously.With the same radiation dose,colony rate in the D group was much less than that in the B group.The Do and Dq values were 0.783 Gy and 2.54Gy in the B group,and in the D group,the Do and Dq were 0.522 Gy and 2.16 Gy.The SERDo was l.36.a/βvalue were 1.78Gy and 9.65Gy respectively, LY294002 can increase the radiosensitization of cell line CNE1.2. The measure result of cell cycles by using FCM displayed that the percentage in G2/M phase increased after CNE1 cell was given by LY294002 as well as single dose 2Gy radiation.The cell cycles in G2/M phase were blocked significantly (p<0.05)in the D group .Apoptosis rates in the C group Was higher than that in the B group,which was4.63 times and 3.54 times than that in the A group.Apoptosis rates in the D group was the hightest and was 6.33 times than that in the A group(p<0.05).statistical analysis demonstrated that the percentage in G2/M phase had good relationship with apoptosis rates(rs=0.863,p<0.05).3. According to the control group,the expressive level of Bad mRNA of the D group are higher,and Ku70 mRNA expression are lower,Ku80 mRNA expression is not changed significantly.4. The expressive level of Bad protein of the D group are higher than control group,pAkt protein are lower.Ly294002 could partially inhibit phosphorylated Akt but not radiation.The combination of both could enhance the inhibition of phosphorylated Akt. [Conclusion]1. LY294002 can increase the radiosensitization of nasopharyngeal carcinoma cell line CNE1.2. LY294002 Inhibited the expressive level of pAkt protein and the P13K/Akt signal transduction pathway was suppressed .3.Inhibiting P13K/Akt signal transduction pathway may increase radiosensitization of CNE1 cell in three aspects:①The cell cycles was changed and the percentage in G2/M phase increased signally;②Inhibiting Ku70 to suppress the DNA recovery after damaging ;③Enhancing the expression of Bad to promote cell apoptos.