Effects of Different Glucose Concentrations and Hypoxia and its Impact on the Expression of Sox2 and CAIX in Breast Cancer: In Vitro And Silico Analysis.

[BACKGROUND] Cancer is a an uncontrolled proliferation of transformed cells as a genetic variation in human diseases. In the present study, we investigated how different concentrations of glucose and hypoxia affect the expression of CAIX and Sox2 genes in breast cancer cell lines MCF-7 and MDA-MB-231.

[METHODS] MCF-7 and MDA-MB-231 cells were exposed to different concentrations of glucose (5.5, 11, and 25 mM), normoxia, and hypoxia. SNARF-AM labeling was used to quantify intracellular pH, which was then evaluated using flow cytometry. Finally, the expression levels of CAIX and Sox2 genes were examined using quantitative real-time PCR. In addition, the interaction of the ligand with carbonic anhydrase was analyzed using Chimera software, and the docking results were checked in the corresponding servers. The relationship between structural disorder and pH was investigated using DispHred.

[RESULTS] Metastasis and intracellular pH (pHi) are glucose-dependent in MCF-7 cells, but hypoxia-dependent in MDA-MB-231 cells. Our findings showed a significant increase in the expression of CAIX (P = .0032) and but Sox2 (P = .5309) also had an increase in expression, it was not significant in the MCF-7 cell line compared with control cells maintained in normal oxygen. In addition, the genes CAIX (P = .0712) and Sox2 (P = .0004) were up-regulated in MDA-MB-231 cells. The DispHred results showed that the total CAIX load changes somewhat with pH changes.

[CONCLUSIONS] Increased or decreased glucose concentration and hypoxia lead to changes in the gene expression patterns of cancer cells. Consequently, the genes may be used as biomarkers to aid in the diagnosis and prognosis of breast cancer.