Benzyl isothiocyanate (BITC) is among the compounds of ITCs’ family that has attracted a great deal of interest because of its ability to exhibit anticancer activity. Dephosphorylation of eukaryotic initiation factor 4G could contribute to the inhibition of Mcl-1 translation mediated by BITC. Furthermore, ectopic expression of Mcl-1 substantially attenuates BITC-mediated lethality in these cells, whereas knockdown of Mcl-1 through small interfering RNA significantly enhances BITC-mediated lethality. Finally, administration of BITC markedly inhibited tumor growth and induced apoptosis in Jurkat xenograft model in association with the downregulation of Mcl-1. Taken together, these findings represent a novel mechanism by which agents targeting Mcl-1 potentiate BITC lethality in transformed and primary human leukemia cells and inhibitory activity of tumor growth of Jurkat xenograft model. mice by BITC has also been documented.5, 6 Preclinical data has illustrated that BITC emerges as a promising anticancer agent and it would be meaningful and challenging to develop this compound to be a novel antitumor drug.7 Currently, ITCs are in human clinical trial for treating cancer.8 Evidence supports that BITC exerts its antiproliferative effects through inducing cell cycle arrest and apoptosis.9 Several signaling pathways have been reported to be involved in BITC-triggered apoptosis, for example, p53-independent X-linked inhibitor of apoptosis (XIAP) downregulation, and reactive oxygen species (ROS) and Bcl2-associated X protein (Bax)/Bak-dependent pathway found in breast cancer cells,10, 11 and ROS, p38- mitogen-activated protein kinases, signal transducer and activator of transcription-3, PI3K/Akt/Foxo, and nuclear factor-results indicate that BITC-mediated inhibition of growth of mouse Jurkat xenograft tumors was in association with the downregulation of Mcl-1 and induction of apoptosis. The results of this study further elucidate the mechanism of BITC as an antileukemic agent. Results BITC potently induces apoptosis in dose- and time-dependent manners A dose-dependent study in Chlorthalidone Jurkat cells revealed a moderate increase in apoptosis 12?h after exposure to 4?and nuclear apoptosis-inducing factor (AIF) accumulation (Figure 1c). The increased level of AIF was determined in the nucleus of cells treated with BITC in a time-dependent manner (Figure 1d). Exposure of Jurkat cells to BITC results in the downregulation of Mcl-1 and translocation of Bax The effects of BITC on the expression of antiapoptotic B-cell lymphoma 2 (Bcl-2) family proteins were examined in Jurkat cells. A marked dose-dependent decrease of Mcl-1 expression was mentioned in BITC-treated cells. Publicity of cells to 8?launch, and Mcl-1 downregulation (Numbers 3b and c). Nevertheless, HL-60 cells tend to be more refractory to apoptosis induction by BITC than those cells, and exhibited much less examples of -3 and caspase-9 activation, cytochrome launch, and Mcl-1 downregulation. Open up in another window Physique 3 Exposure to BITC results in a marked increase in apoptosis in Mouse monoclonal to OLIG2 association with Mcl-1 downregulation in multiple leukemia cell lines and primary human leukemia cells but not normal human peripheral blood mononuclear cells. (a) U937, Jurkat, and HL-60 cells were treated with or without 8?luciferase was monitored as described in the Materials and Methods section. Values for firefly luciferase activity were normalized to those obtained for luciferase activity, after which values obtained for (?203/+10-Mcl-1-pGL2)-transfected cells were divided by the corresponding values obtained for pGL2-Basic-transfected cells. The graph shown represents the meanS.D. in four individual experiments. (c) Jurkat cells were treated with MG132 (10?and (Figures 6a and b). Although a slight Chlorthalidone reduction in the expression of ectopic Mcl-1 was Chlorthalidone observed in infectants exposed to 8?test; test; (Physique 6e). Furthermore, contamination of cells with Mcl-1 siRNA reduced levels of total Mcl-1 compared with control cells. Exposure of these cells to BITC resulted in a significant reduction of Mcl-1 expression compared with control cells (Physique 6f). Taken together, these findings indicate that Mcl-1 downregulation has a significant functional role in BITC-mediated lethality. BITC exhibits antitumor Chlorthalidone activity in xenografts of leukemia Jurkat cells by induction of apoptosis and downregulation of Mcl-1 The antitumor activity of BITC on leukemia Jurkat cells was further evaluated in.