Investigation of the effects of Biochanin A usage on endoplasmic reticulum stress in glioblastoma cancer cells

Glioblastoma multiform (GBM) is one of the commonly observed malignant primary tumors of the brain. GBM is a central nervous system tumor characterized by a low survival rate and a high risk of recurrence. Surgical tumor resection is performed with temozolomide (TMZ) chemotherapy and radiation therapy as part of the traditional treatment of GBM. Though even with these treatments, the survival rate is around 5% in the first five years. Due to the lack of selectivity of the treatment methods used and the high dose requirement, the effects of flavonoids on treatment have begun to be investigated in current studies. Flavonoids are natural compounds found in vegetables, fruits and herbal beverages and have antioxidant, antimutagenic and antiproliferative properties. Biochanin A, which is included in the isoflavone group, one of the subclasses of flavonoids, is known to have potential chemopreventive and anticancer properties against various cancer cells such as glioblastoma, oral and breast cancer.The aim of this thesis is to investigate the effect of the use of Biochanin A in GBM, which is known to have an effect on various cancers in the literature, on Endoplasmic Reticulum Stress. Within the scope of this thesis, the T98G glioma cell line was used for the experimental studies. In order to determine the optimal concentration of Biochanin A to be applied in the experiments, % cell viability was calculated using the MTT method and it was planned to apply at a concentration of 100uM for 48 hours. Apoptotic cell ratios after treatment of Biochanin A were determined by flow cytometry using Annexin V-FITC. The data obtained showed, after the treatment of Biochanin A, late apoptosis was induced in the treated cells compared to the normal cells without treatment. No statistically significant difference was found between the DMSO-treated cells that were used as controls and the Biochanin-A-treated cells. In order to investigate the relationship of Biochanin A usage on ER stress, the expressions of GADD153, GRP78, ATF4, EIF2S1 and XBP1 genes associated with ER stress were examined using the Quantitative Real-time PCR method. A significant increase in ATF4 gene expression was observed for 48 hours. Finally, intracellular Ca+2 amounts were determined by Calcium flux assay. No change in intracellular Ca+2 release levels was observed after treatment. The results obtained within the scope of the thesis showed that Biochanin A causes a significant change in the expression of the ATF4 gene in T98G cells and induces late apoptosis in treated cells compared to non-treated normal.