| This thesis observed the different expressions of DNA repair genes ofesophageal carcinoma cells at different time after X-ray irradiation,andinvestigated the role of those DNArepair genes in radiation resistance.Oesophageal cancer parent cell lines Seg-1 were treated withcontinuous 2Gy fractionated irradiation (total dose 60 Gy), andradioresistant cell lines Seg-1R were established. Total RNA was extractedfrom each cell line at different time before irradiation (0h) and afterirradiation (8h, 24h). Identified differentially expressed genes betweenparent and radioresistant cells on illumine Human-6 V3 chip, and observedthe gene expression variances of each cell line. By Cluster analysis, thesimilar gene expressions of three samples at different time after irradiation(0h, 8h, 24h) were compared. By Gene Ontology analysis, some genes ofdifferent expression involved in DNA repair were obtaind, the varioustrends of these genes at different time after irradiation were analyzed,andthese data were authenticated by RT-PCR.The gene expression of cell sample at 24h after irradiation was similarto that of cell sample at 0h after irradiation, and that of cell sample at 8hafter irradiation was more diversely expressed. The genes expresseddifferentially were involved in signal transduction, cell cycle,phosphorylation, DNA repair and so on. 5 DNA repair genes associatedwith DNA repair of different expression were found by Gene Ontologyanalysis. SLK,HMGB1 and PMS1 were expressed more obviously notonly between parent cell line and radioresistant cell line, but also atdifferent time after irradiation in the same cell line,which were coincidentto the results of RT-PCR . The gene expressions of parent and radioresistant cells at 24h afterirradiation were mainly recovered to the incipient level,but the geneexpression of cell sample at 8h after irradiation was still in changingperiod,PMS1 may play an important role in the mechanism of radiationresistance of esophageal carcinoma cells. |
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