title: Downregulation of Mcl-1 through inhibition of translation contributes to benzyl isothiocyanate-induced cell cycle arrest and apoptosis in human leukemia cells.
abstract: Benzyl isothiocyanate (BITC) is one of the compounds of ITCs' family that has attracted a great deal of interest because of its ability to exhibit anticancer activity. In this study, we investigated the effects of BITC on cell cycle arrest and apoptosis in human leukemia cell lines, primary leukemia cells, and nude mice Jurkat xenograft. Exposure of Jurkat cells to BITC resulted in dose- and time-dependent increase in apoptosis, caspase activation, cytochrome c release, nuclear apoptosis-inducing factor (AIF) accumulation, Bcl2-associated X protein (Bax) translocation, and myeloid cell leukemia-1 (Mcl-1) downregulation. Treatment with these cells also resulted in cell cycle arrest at the G2/M phase. The G2/M-arrested cells are more sensitive to undergoing Mcl-1 downregulation and apoptosis mediated by BITC. BITC downregulates Mcl-1 expression through inhibition of translation, rather than through a transcriptional, post-translational, or caspase-dependent mechanism. 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.
authors: Department of Pharmacognosy, School of Pharmacy, 3rd Military Medical University, Chongqing, China.
authors: T
authors: T
authors: Zhou
authors: G
authors: G
authors: Li
authors: B
authors: B
authors: Cao
authors: L
authors: L
authors: Liu
authors: Q
authors: Q
authors: Cheng
authors: H
authors: H
authors: Kong
authors: C
authors: C
authors: Shan
authors: X
authors: X
authors: Huang
authors: J
authors: J
authors: Chen
authors: N
authors: N
authors: Gao
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D051033:Apoptosis Inducing Factor / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D039603:Eukaryotic Initiation Factor-4G / Q000378:metabolism; D059565:G2 Phase Cell Cycle Checkpoints / Q000187:drug effects*; D018922:HL-60 Cells; D006801:Humans; D017879:Isothiocyanates / Q000627:therapeutic use / Q000633:toxicity*; D019169:Jurkat Cells; D007938:Leukemia / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D059566:M Phase Cell Cycle Checkpoints / Q000187:drug effects*; D051379:Mice; D008819:Mice, Nude; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D014176:Protein Biosynthesis / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D051033:Apoptosis Inducing Factor; D039603:Eukaryotic Initiation Factor-4G; D017879:Isothiocyanates; C579094:Mcl1 protein, mouse; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D051028:bcl-2-Associated X Protein; C031403:benzyl isothiocyanate