Figure 6

Expression of Na ⁺ /K ⁺ -ATPase subunits in LN229/T98G cells and human astrocytes. The expression of Na⁺/K⁺-ATPase three α subunits was detected using reverse transcriptase PCR analysis in glioblastoma cell lines LN229 and T98G as well as in human astrocytes. A. RT-PCR result shows different mRNA levels of α1, α2 and α3 subunits in the three cell types. Ribosomal protein-19 (RPL-19) was measured as a housekeeper gene for loading control. B. Quantified data in the bar graph show that T98G cells express higher α1 mRNA levels compared to LN229 cells but there is no difference in α1 mRNA levels compared to human astrocytes. N = 3 in each group; * P < 0.05 vs. human astrocytes; ^# P < 0.05 vs. LN229 cells. C and D. Quantified RT-PCR data on α2 (C) and α3 (D) subunits. Both subunits were highly expressed in T98G cells and were significant different from those in LN229 cells and human astrocytes. E. MTT assay of cell viability showed that ouabain treatment (0.1 - 5 μM for 6 hrs) significantly reduced the cell viability in T98G cells compared to LN229 cells. F. MTT assay confirmed a higher resistance of T98G cells to TMZ (0.01 – 100 μM for 24 hrs) compared to LN229 cells. ^* P < 0.05 vs. LN229 cells. G. MTT assay showed that co-treatment of ouabain (0.1 μM) and TMZ (100 μM) for 24 hrs significantly augmented the cell vulnerability to TMZ. ^* P < 0.05 vs. control, ^# P < 0.05 vs. TMZ alone.