Fig. 6
Overexpression of TRPA1 Induced Cell Apoptosis and ROS Production via Increased Intracellular Ca2+ Levels in TMZ-Stimulated U251 Cells. A Transfection of U251 cells with TRPA1 shRNA upregulated (TRPA1+/+) TRPA1 protein expression at 12 h compared with control shRNA (Con) treatment. The cropped blots are displayed. B The level of Ca2+ influx changed. TMZ stimulation showed different effects on cell viability (C), the expression of the Cleaved Caspase-3 protein (D), the activity of Caspase-3 (E) and Caspase-9 (F), and the level of apoptosis proteins (G) in Con and TRPA1+/+ U251 cells. Additionally, the effects of TMZ on the protein expression of MGMT (H), the levels of the cell antioxidant genes MnSOD, NQO1 and HO-1, and antioxidants GSH (I). intracellular ROS (J) and mitochondrial ROS (K), as well as the levels of mitochondrial structural proteins (L) in Con and TRPA1+/+ U251 cells. GAPDH was used as an internal reference. The cropped blots were displayed, and the expression level was quantified densitometry with ImageJ software. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001