Benzyl isothiocyanate (BITC) induces apoptosis of GBM 8401 human brain glioblastoma multiforms cells via activation of caspase‐8/Bid and the reactive oxygen species‐dependent mitochondrial pathway

Benzyl isothiocyanate (BITC) is one of member of the isothiocyanate family which has been shown to induce cancer cell apoptosis in many human cancer cells. In the present study, we investigated the effects of BITC on the growth of GBM 8401 human brain glioblastoma multiforms cells. Results indicated that BITC‐induced cell morphological changes decreased in the percentage of viable GBM8401 cells and these effects are dose‐dependent manners. Results from flow cytometric assay indicated that BITC induced sub‐G1 phase and induction of apoptosis of GBM 8401 cells. Furthermore, results also showed that BITC promoted the production of reactive oxygen species (ROS) and Ca²⁺ release, but decreased the mitochondrial membrane potential (ΔΨₘ) and promoted caspase‐8, ‐9, and ‐3 activates. After cells were pretreated with Z‐IETD‐FMK, Z‐LEHD‐FMK, and Z‐DEVD‐FMK (caspase‐8, ‐9, and ‐3 inhibitors, respectively) led to decrease in the activities of caspase‐8, ‐9, and ‐3 and increased the percentage of viable GBM 8401 cells that indicated which BITC induced cell apoptosis through caspase‐dependent pathways. Western blotting indicated that BITC induced Fas, Fas‐L, FADD, caspase‐8, caspase ‐3, and pro‐apoptotic protein (Bax, Bid, and Bak), but inhibited the ant‐apoptotic proteins (Bcl‐2 and Bcl‐x) in GBM 8401 cells. Furthermore, BITC increased the release of cytochrome c, AIF, and Endo G from mitochondria that led to cell apoptosis. Results also showed that BITC increased GADD153, GRP 78, XBP‐1, and ATF‐6β, IRE‐1α, IRE‐1β, Calpain 1 and 2 in GBM 8401 cells, which is associated with ER stress. Based on these observations, we may suggest that BITC‐induced apoptosis might be through Fas receptor, ROS induced ER stress, caspase‐3, and mitochondrial signaling pathways. Taken together, these molecular alterations and signaling pathways offer an insight into BITC‐caused growth inhibition and induced apoptotic cell death of GBM 8401 cells. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1751–1760, 2016.