Effect Of Recombinant Adenovirus P53(rAd-p53) Injection Combined With Radiotherapy On Nasopharyngeal Carcinoma Cell

Radiation therapy has become routine treatment for cancer therapy. However, in the same treatment conditions, even if the tumor types, pathological grade, location of the patients are the same, the effects of the same treatment are quite different. It indicates that the intrinsic radio-sensitivity of tumor cells are significantly different. The relative studies on the intrinsic radio-sensitivity of tumor molecules and cell biology show that radiotherapy initiates apoptosis of tumor cells mainly by making DNA damages of tumor cells and apoptosis-related changes in gene or protein, it has been proved that, DNA-PK, Ku70, Ku80, ATM protein, p53 protein in connection with the repair capacity of the damage of DNA double-strand breaks and p53, p16, bcl-2 and other gene expression products in connection with apoptosis and control-related cycle are related with the tumor radio-sensitivity.Objective:To evaluate the effect of the recombinant adenovirus p53 (rAd-p53) injection on the radio-sensitivity of nasopharyngeal carcinoma cell line CNE2 cells.Methods:Divide CNE2 cells into 5 groups:the blank group (B group), the control group (C group), the plus rAd-p53 group (D group), the radio-therapy group(R group), and the combined treatment group (D+R group). Firstly transfect rAd-p53 into CNE2 cells to assay the growth inhibition rate of CNE2 cells under the different concentrations of rAd-p53 by MTT, Secondly choose the best one; Then analysis the effect of CNE2 cells' apoptosis combining rAd-p53 with radiotherapy using flow cytometry.Results:1.Before the experiment the CNE2 cells are close-wall and spindle cells, which are in close arrangement and fast growth (2 to 3 days per generation).After adding rAd-p53 for 12 hours, it is observed by microscope that the shape of cell changes to round; the volume shrinks small; the density increase; the cell membrance and nuclear membrane is integrated; the mitochondria concentrate and chromatin shrinks and collapse outwards to from one or more block-sharp "high-density sphere" or "burgeon" out-wards to form small sphere with grape bunch sharp. After 24 hours, it is observed by microscope that the membrane is damaged, swelled and cra-cked.2.It is found by MTT that with the increase of concentration of rAd-p53 the growth inhibition rate of CNE2 cells of nasopharyngeal carcinoma cell line increases. The growth inhibition rate of the high concentration group reaches 85.46% with a good dose-effect relationship (P=0.000). The best concentration of rAd-p53(IC50) is 8.72×107VP/ml.3.The results of flow cytometry analysis are as follows:the CNE2 cells apoptosis rate of C group is (5.363±0.347)%, D group is (10.450±0.507)%, R group is (20.373±0.970)%, D+R is(27.207±6.000)%(P< 0.05). The CNE2 cells apoptosis rate of D+R group obviously increases.Conclusion:1.rAd-p53 injection have a significantly inhibition of CNE2 cells of nasopharyngeal carcinoma cell lines. The higher the concentration is, the better inhibition effect get which shows a good quantity-effect relation.2.Radiotherapy has the ability of killing CNE2 cells of nasopharyngeal carcinoma cell lines and rAd-p53 injection combined with radiotherapy enhanced the radio-sensitivity of CNE2 cells of nasopharyngeal carcinoma cell line.3.This experiment is a part of the clinical trial, which has a quantity of shortages due to the limited time, finite knowledge and experiment skills. It is necessary to take further study as to the issue of the dose-effect relation between radiotherapy effection and rAd-p53 injection.