title: Role of PI3K/Akt and MEK/ERK signaling pathways in sulforaphane- and erucin-induced phase II enzymes and MRP2 transcription, G2/M arrest and cell death in Caco-2 cells.
abstract: Isothiocyanate sulforaphane is an extensively studied cancer chemopreventive agent in human diet. In this study, the effects of sulforaphane (SFN) and its sulfide analog, erucin (ERN), have been examined on the induction of the phase II enzymes, quinine oxidoreductase (NQO1) and UDP-glucuronosyl transferase (UGT1A1), multidrug transporter (MRP2), cell cycle arrest and cell death in human colon adenocarcinoma Caco-2 cells. Additionally, the roles of PI3K/Akt and MEK/ERK signaling pathways have been assessed in these sulforaphane- and erucin-induced events. Although erucin and sulforaphane have similar IC50 values (21 and 23 microM after 72 h treatment), erucin was more effective in the induction of G2/M accumulation, depletion of mitochondrial potential, induction of cell death and mRNA induction of phase II enzymes and MRP2. Erucin (20 microM) induced the mRNAs of NQO1, UGT1A1 and MRP2 by 11.1-, 11.6- and 6.7-fold, whereas sulforaphane (20 microM) induced 3.3-, 5.3- and 2.2-fold, respectively. Both erucin and sulforaphane induced activation (phosphorylation) of ERK1/2 and Akt kinases but had no effect on JNK and p38 activation. Erucin-induced phase II enzyme transcriptions were decreased by PI3K and MEK1 inhibitors (LY294002 and PD98059), but the decreases in sulforaphane-induced transcription were less marked. Erucin induced a large increase in G2/M cell number than sulforaphane. The ability of kinase inhibitors to overcome G2/M block was low with the exception of PD98059 in sulforaphane-treated cells. Both, sulforaphane and erucin at high concentrations induced accumulation of sub-G1 cells, cell death and dissipation of mitochondrial membrane potential. Taken together, these results demonstrate that PI3K/Akt and MEK/ERK signals are important intracellular mediators in erucin- and sulforaphane-mediated phase II enzyme transcription and cell cycle arrest in Caco-2 cells.
authors.affiliation: Nutrition Division, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
authors.forename: Jana
authors.initials: J
authors.lastname: Jakubíková
authors.forename: Ján
authors.initials: J
authors.lastname: Sedlák
authors.forename: Richard
authors.initials: R
authors.lastname: Mithen
authors.forename: Yongping
authors.initials: Y
authors.lastname: Bao
mesh_terms: D018938:Caco-2 Cells; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology*; D004790:Enzyme Induction / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000502:physiology; D016195:G2 Phase / Q000187:drug effects / Q000502:physiology*; D014453:Glucuronosyltransferase / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D017879:Isothiocyanates; D020930:MAP Kinase Kinase Kinases / Q000502:physiology; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics* / Q000378:metabolism; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000096:biosynthesis / Q000235:genetics; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D051057:Proto-Oncogene Proteins c-akt; D013440:Sulfides / Q000494:pharmacology*; D013454:Sulfoxides; D013861:Thiocyanates / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects / Q000502:physiology; D000099148:UGT1A1 Enzyme
chemical_list: D004791:Enzyme Inhibitors; D048049:Extracellular Signal-Regulated MAP Kinases; D014453:Glucuronosyltransferase; D017879:Isothiocyanates; D020930:MAP Kinase Kinase Kinases; D026901:Membrane Transport Proteins; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D016660:NAD(P)H Dehydrogenase (Quinone); D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D013440:Sulfides; D013454:Sulfoxides; D013861:Thiocyanates; D000099148:UGT1A1 Enzyme; C000715087:ABCC2 protein, human; C073539:erucin; C447479:NQO1 protein, human; C494918:AKT1 protein, human; C016766:sulforaphane