title: PEITC-mediated inhibition of mRNA translation is associated with both inhibition of mTORC1 and increased eIF2α phosphorylation in established cell lines and primary human leukemia cells.
abstract: Increased mRNA translation drives carcinogenesis and is an attractive target for the development of new anti-cancer drugs. In this work, we investigated effects of phenethylisothiocyanate (PEITC), a phytochemical with chemopreventive and anti-cancer activity, on mRNA translation. PEITC rapidly inhibited global mRNA translation in human breast cancer-derived MCF7 cells and mouse embryonic fibroblasts (MEFs). In addition to the known inhibitory effects of PEITC on mTORC1 activity, we demonstrate that PEITC increased eIF2α phosphorylation. PEITC also increased formation of stress granules which are typically associated with eIF2α phosphorylation and accumulation of translationally stalled mRNAs. Analysis of genetically modified MEFs demonstrated that optimal inhibition of global mRNA translation by PEITC was dependent on eIF2α phosphorylation, but not mTORC1 inhibition. We extended this study into primary leukemic B cells derived from patients with chronic lymphocytic leukaemia (CLL). CLL cells were stimulated in vitro with anti-IgM to mimic binding of antigen, a major driver of this leukemia. In CLL cells, PEITC increased eIF2α phosphorylation, inhibited anti-IgM-induced mTORC1 activation and decreased both basal and anti-IgM-induced global mRNA translation. PEITC also inhibited transcription and translation of MYC mRNA and accumulation of the MYC oncoprotein, in anti-IgM-stimulated cells. Moreover, treatment of CLL cells with PEITC and the BTK kinase inhibitor ibrutinib decreased anti-IgM-induced translation and induced cell death to a greater extent than either agent alone. Therefore, PEITC can inhibit both global and mRNA specific translation (including MYC) via effects on multiple regulatory pathways. Inhibition of mRNA translation may contribute to the chemopreventive and anti-cancer effects of PEITC.
authors: Cancer Research UK Centre, Faculty of Medicine, University of Southampton, Southampton, UK.
authors: Alison
authors: A
authors: Yeomans
authors: Cancer Research UK Centre, Faculty of Medicine, University of Southampton, Southampton, UK.
authors: Elizabeth
authors: E
authors: Lemm
authors: Cancer Research UK Centre, Faculty of Medicine, University of Southampton, Southampton, UK.
authors: Sarah
authors: S
authors: Wilmore
authors: Cancer Research UK Centre, Faculty of Medicine, University of Southampton, Southampton, UK.|Current Address: Public Health England, Porton Down, Salisbury, UK.
authors: Breeze E
authors: BE
authors: Cavell
authors: Cancer Research UK Centre, Faculty of Medicine, University of Southampton, Southampton, UK.
authors: Beatriz
authors: B
authors: Valle-Argos
authors: Cancer Research UK Centre, Faculty of Medicine, University of Southampton, Southampton, UK.|Current Address: Bart's Cancer Institute, Queen Mary University of London, London, UK.
authors: Sergey
authors: S
authors: Krysov
authors: Cancer Research UK Centre, Faculty of Medicine, University of Southampton, Southampton, UK.|Current Address: Department of Pharmacology, Faculty of Pharmacy, University of Seville, Seville, Spain.
authors: Marina Sanchez
authors: MS
authors: Hidalgo
authors: Cancer Research UK Centre, Faculty of Medicine, University of Southampton, Southampton, UK.|Current Address: XPE Pharma and Science, Wavre, Belgium.
authors: Elodie
authors: E
authors: Leonard
authors: MRC Toxicology Unit, Leicester, UK.
authors: Anne E
authors: AE
authors: Willis
authors: Haematology Oncology Group, Cancer Sciences Unit, Cancer Research UK Centre, University of Southampton, Faculty of Medicine, Southampton, UK.|Department of Haematology, University Hospital Southampton NHS Trust, Southampton, UK.
authors: Francesco
authors: F
authors: Forconi
authors: Cancer Research UK Centre, Faculty of Medicine, University of Southampton, Southampton, UK.
authors: Freda K
authors: FK
authors: Stevenson
authors: Cancer Research UK Centre, Faculty of Medicine, University of Southampton, Southampton, UK.
authors: Andrew J
authors: AJ
authors: Steele
authors: Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, UK.
authors: Mark J
authors: MJ
authors: Coldwell
authors: Cancer Research UK Centre, Faculty of Medicine, University of Southampton, Southampton, UK.
authors: Graham
authors: G
authors: Packham
mesh_terms: D000888:Antibodies, Anti-Idiotypic / Q000494:pharmacology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism*; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects; D016259:Genes, myc; D006801:Humans; D017879:Isothiocyanates / Q000494:pharmacology*; D007938:Leukemia / Q000235:genetics* / Q000378:metabolism*; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics / Q000378:metabolism; D061986:MCF-7 Cells; D000076222:Mechanistic Target of Rapamycin Complex 1 / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D014176:Protein Biosynthesis / Q000187:drug effects*; D012333:RNA, Messenger / Q000235:genetics; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism; D013312:Stress, Physiological; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D000888:Antibodies, Anti-Idiotypic; D015852:Eukaryotic Initiation Factor-2; D017879:Isothiocyanates; D012333:RNA, Messenger; D011947:Receptors, Antigen, B-Cell; C044203:anti-IgM; C058305:phenethyl isothiocyanate; D000076222:Mechanistic Target of Rapamycin Complex 1
keywords: MYC; eIF2α; mRNA translation; mTORC1; phenethylisothiocyanate