Figure 5.

KS100 reduced total cellular ALDH activity to increase ROS generation, lipid peroxidation, and toxic aldehyde accumulation leading to apoptosis and autophagy. The ALDHs reduce ROS generation, lipid peroxidation, and toxic aldehyde accumulation, the latter of which can lead to cell damage and apoptosis (A). KS100 was the only ALDH inhibitor that significantly reduced ALDH⁺ cells in both UACC 903 (B) and 1205 Lu (C) cells. ALDH⁺ cells were analyzed byflow cytometry following staining with AldeRed. DMSO served as the control. UACC 903 (D) and 1205 Lu (E) cells treated with KS100 had increased ROS activity compared with the other ALDH inhibitors tested. DMSO served as control. No ALDH inhibitor significantly increased ROS activity in normal human fibroblasts (FF2441) compared with the DMSO control (F). UACC 903 (G) and 1205 Lu (H) cells treated with KS100 had increased lipid peroxidation and toxic aldehyde accumulation compared with the other ALDH inhibitors tested. DMSO served as the control. Flow cytometric analysis of apoptosis in UACC 903 (I) and 1205 Lu (J) cells treated with 5 μmol/L of ALDH inhibitor for 24 hours showed significantly increased apoptosis with KS100 compared with the other ALDH inhibitors tested in both cell lines. DMSO served as the control. Western blot of increasing concentrations of KS100 (2, 4, and 6μmol/L) showed increased apoptosis (cleaved-PARP) and autophagy (LC3B) in UACC 903 cells after 24 hours of treatment (K).