ИСТИНА

Background: The predictors of a favorable prognosis regarding radiation exposure in patients with glioblastoma have not been studied enough, therefore, the search for factors determining a tumor response to the combined chemoradiation treatment is an actual task at present. DNA repair protein RAD51 homolog 1 (RAD51) is a crucial protein for homologous recombination and its inhibition has been shown to sensitize glioma stem cells to irradiation. Materials and Methods: G01 primary glioblastoma cell culture was obtained from tumor tissues from patient with long term survival (42 month).An irradiation with the energy of 6 MeV was carried out in 1 fraction 20,40,60,80,100,125,150,200,250 Gy with Linac. mRNA expression of the RAD51 gene, XRCC6, XRCC5 genes, relative amount of RAD51 protein and Ku70, Ku80 proteins, proliferative activity of cell culture was evaluated by RT-PCR, Western blotting, MTT-test, respectively.Results: When G01 cells were irradiated with doses from 5 to 180 Gy there was a uniform linear decrease in the population of proliferating cells compared to the control, but at a dose of 200 Gy a rise to 24% was observed. The mRNA expression of the RAD51 gene increased 2 times after irradiation at a dose of 20 Gy compared with control and then increased, reaching a peak at the level of 100,250 Gy. Minimal expression was observed after irradiation at a dose of 20 and also decreased at 200 Gy. The mRNA expression of the XRCC5 gene increased 2-fold after irradiation at a dose of 20 Gy compared with control and then decreased, remaining at the same level. Minimal expression was observed after irradiation at a dose of 200Gy. The relative amount of Ku80 protein reached a peak at a dose of 100 Gy, followed by a decrease. Maximum expression level of mRNA of the XRCC6 gene was observed after irradiation at a dose of 250Gy. The relative amount of Ku70 protein also decreased at 200 Gy and reached a peak at a dose of 250 Gy. Conclusions: After irradiation transplantable G01 cell culture from patient with long term survival a linear decrease in proliferative activity depending on the dose was observed with an decrease in mRNA expression of Rad51 gene and the relative amount of RAD51,Ku70 in dose level of 200Gy that could potentially indicate sensitivity point to radiation exposure in these cell culture. Further studies using cell cultures from patients may help in understanding the mechanisms of radioresistance and radiosensitivity in glioblastoma.The research was supported financially by RFBR (Project No. 18-29-01061). https://www.abstractsonline.com/cSubmit/SubmitPrinterFriendlyVersion.asp?ControlKey=%7B8F02CD80%2DCDEE%2D4116%2D813E%2DF9E7F27B5290%7D&MeetingActivityKey=%7B20774C0A%2D352D%2D4CF8%2DB527%2D84C77BE63D7F%7D&AKey=%7B384D2523%2DAA39%2D4B08%2DA120%2D38A9AB93ADA3%7D&MKey=%7BC8AD1DA9%2D715B%2D45C7%2DA15E%2D6A01D89D04F6%7D