Figure 4. Phenformin treatment combined with siRNA of ALDH1L1 synergistically reduced ATP production.

(A, B) After incubation with ALDH1L1 siRNA, cells were treated with 100 μM phenformin for 24 h before assessment of NADH/NAD+ (A), ATP (B). (C) Immunoblot analysis was performed to confirm ALDH1L1 knockdown. (D) Tetramethylrhodamine ethyl ester (TMRE) staining was performed to examine changes in mitochondrial membrane potential. Data are representative of the mean and standard deviation of three independent experiments. **p < 0.01, ***p < 0.001 compared to vehicle control.