BQ788 Induced Glioblastoma Stem Cell Differentiation And Apoptosis Increase Its Radiosensitivity Study

Objective Glioblastoma(GBM) is one of the most lethal tumors. If the patients suffered GBM are not treated in time, the median survival time is only about 3 months. At present, the standard treatment of GBM is for the maximization of surgical resection of the tumor, postoperative radiotherapy, combined with chemotherapy for the treatment of chemotherapy, as well as the comprehensive treatment of immunotherapy. However, after the standard treatment,the median survival time was only 14.6 months. The mostly commonly factor leading to the recurrence and refractory is the resistibility of of glioblastoma cell tumor stem cells(GSCs) to radiotherapy and chemotherapy. Studies have reported that the secretion of endothelin and the expression of its receptor are much higher in many malignant tumors such as prostate cancer, lung cancer, bladder cancer, ovarian cancer and melanoma tumor, suggesting that the endothelin system may be one of the potential target for antitumor therapy. At present, some studies have showed that endothelin receptor antagonist(BQ788) can inhibit the migration of GSCs and induce the apoptosis of GSCs. The study, which are about BQ788 inducing the differentiation of GSCs and on the resistance to radiotherapy of GSCs,have not been reported. Our study mainly explores the effect of BQ788 on the differentiation of GSCs, and the effect of BQ788 on the enhancing sensitivity of radiotherapy, and then evaluate the value of BQ788 in the treatment of patients with malignant glioma.Methods(1)Different concentrations of BQ788 were used to the human gliomatumor stem cell lines, NCH-421 k and NCH-644 cells, 48 hours after application of CCK-8 to detect the growth state.(2) Human glioblastoma stem cell lines NCH-421 k and NCH-644 two cell lines were used 75 umol / L of BQ788 medium for 1 week induced to differentiate into NCH-421k-dif and NCH-644-dif.(3) Using flow cytometry and immunofluorescence staining method to identify differentiated cells Stem cells and expression of molecular markers characteristic.(4) Ordinary glioma stem cell line(NCH-421k) and radioresistance of glioma stem cell line(NCH-421k-IR) were simple application BQ788 treatment, radiotherapy alone application processing, application BQ788 and radiotherapy treatment, they detect changes in radiotherapy(radiation dose 2Gy) after the rate of apoptosis and cell cycle. BQ788 detected by western blot and drug treatment group, radiation treatment combined with radiotherapy group and BQ788 treated apoptosis index pro-casp3. Using SPSS 19.0 statistical software for data statistical analysis.Results(1) BQ788 drugs of glioma stem cells showed a dose-dependent manner, while BQ788 concentration <50umol/L when no inhibition of growth GSCs; and when BQ788 concentration> 50umol/L, namely 75umol/ L, 100umol/L when you showed inhibition GSCs growth.(2) NCH-421 k and NCH-644 were applied containing 75umol/BQ788 week of culture medium L cell morphology part of the cell by a ball of cells gradually become fusiform, appeared adherent growth.(3) Decreased by flow cytometry and immunofluorescence glioma stem cells and differentiated cells NCH-421 k NCH-421k-dif stem cell markers CD133 and Nestin, GFAP and differentiation markers significantly increased.(4) The simple application of BQ788 drug treatment, the simple application of radiotherapy treatment, BQ788 combined with radiotherapy were treated NCH-421kand NCH-421k-IR cells in the two groups, comparing with the control group, the apoptosis rate was significantly increased, while BQ788 combined with radiotherapy group the highest rate of apoptosis, BQ788 drug-treated groups, followed by a relatively low radiotherapy alone group.(5) Comparison of radiation resistant cell NCH-421k-IR with common glioma cells NCH-421 k cells in both groups were BQ788 simple application of drug treatment, radiotherapy treatment and apoptosis rate under conditions BQ788 combined with radiotherapy treatment of the former apoptosis rates were lower than the latter.Conclusions 1. Endothelin receptor antagonist(BQ788) can inhibit GSCs growth. 2. BQ788 induce differentiation of GSCs, after a week,glioblastoma stem cell markers CD133 GSCs and Nestin expression was significantly reduced, and differentiation marker GFAP expression was significantly higher. 3. The higher concentrations of BQ788 can induce GSCs to apoptosis, but had no significant effect on the cell cycle. 4. BQ788 can increase the radiosensitivity GSCs.