Beta-eleostearic acid induce apoptosis in T24 human bladder cancer cells through reactive oxygen species (ROS)-mediated pathway

Beta-eleostearic acid (β-ESA, 9E11E13E-18:3), a linolenic acid isomer with a conjugated triene system, is a natural and biologically active compound. Herein, we investigated effects of β-eleostearic acid on T24 human bladder cancer cells. In this study, results showed that β-eleostearic acid had strong cytotoxicity to induce cell apoptosis, which was mediated by reactive oxygen species (ROS) in T24 cells. The cell viability assay results showed that incubation with β-eleostearic acid concentrations of 10-80μmol/L caused a dose- and time-dependent decrease of T24 cell viability, and the IC(50) value was 21.2μmol/L at 24h and 13.1μmol/L at 48h. Annexin V/PI double staining was used to assess apoptosis with flow cytometry. Treatment with β-eleostearic acid caused massive ROS accumulation and GSH decrease, which lead to activation of caspase-3 and down-regulation of Bcl-2 indicating induction of apoptosis. Subsequently, N-acetyl-l-cysteine (NAC) and PEG-catalase effectively blocked the ROS elevated effect of β-eleostearic acid, which suggested that β-eleostearic acid-induced apoptosis involved ROS generated. Additionally, we found that treating T24 cells with β-eleostearic acid induced activation of PPARγ. A PPARγ-activated protein kinase inhibitor was able to partially abrogate the effects of β-eleostearic acid. These results suggested that β-eleostearic acid can induce T24 cells apoptosis via a ROS-mediated pathway which may be involved PPARγ activation.