title: The MAPK pathway signals telomerase modulation in response to isothiocyanate-induced DNA damage of human liver cancer cells.
abstract: 4-methylthiobutyl isothiocyanate (MTBITC), an aliphatic, sulphuric compound from Brassica vegetables, possesses in vitro and in vivo antitumor activity. Recently we demonstrated the potent growth inhibitory potential of the DNA damaging agent MTBITC in human liver cancer cells. Here we now show that MTBITC down regulates telomerase which sensitizes cells to apoptosis induction. This is mediated by MAPK activation but independent from production of reactive oxygen species (ROS). Within one hour, MTBITC induced DNA damage in cancer cells correlating to a transient increase in hTERT mRNA expression which then turned into telomerase suppression, evident at mRNA as well as enzyme activity level. To clarify the role of MAPK for telomerase regulation, liver cancer cells were pre-treated with MAPK-specific inhibitors prior to MTBITC exposure. This clearly showed that transient elevation of hTERT mRNA expression was predominantly mediated by the MAPK family member JNK. In contrast, activated ERK1/2 and P38, but not JNK, signalled to telomerase abrogation and consequent apoptosis induction. DNA damage by MTBITC was also strongly abolished by MAPK inhibition. Oxidative stress, as analysed by DCF fluorescence assay, electron spin resonance spectroscopy and formation of 4-hydroxynonenal was found as not relevant for this process. Furthermore, N-acetylcysteine pre-treatment did not impact MTBITC-induced telomerase suppression or depolarization of the mitochondrial membrane potential as marker for apoptosis. Our data therefore imply that upon DNA damage by MTBITC, MAPK are essential for telomerase regulation and consequent growth impairment in liver tumor cells and this detail probably plays an important role in understanding the potential chemotherapeutic efficacy of ITC.
authors: Department of Environmental Health Sciences, University Medical Center Freiburg, Freiburg, Germany. evelyn.lamy@uniklinik-freiburg.de
authors: Evelyn
authors: E
authors: Lamy
authors: Corinna
authors: C
authors: Herz
authors: Sabine
authors: S
authors: Lutz-Bonengel
authors: Anke
authors: A
authors: Hertrampf
authors: Melinda-Rita
authors: MR
authors: Márton
authors: Volker
authors: V
authors: Mersch-Sundermann
mesh_terms: D000970:Antineoplastic Agents / Q000008:administration & dosage*; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D004249:DNA Damage / Q000187:drug effects / Q000235:genetics; D015536:Down-Regulation / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D017879:Isothiocyanates / Q000008:administration & dosage*; D008113:Liver Neoplasms / Q000188:drug therapy / Q000235:genetics*; D048670:MAP Kinase Kinase 4 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress; D015398:Signal Transduction; D019098:Telomerase / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism
chemical_list: C447639:4-(methylthio)-3-butenyl isothiocyanate; D000970:Antineoplastic Agents; D017879:Isothiocyanates; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases; D019098:Telomerase
references: Mol Cancer. 2005 Jul 15;4:24
references: 16022731
references: Nucleic Acids Res. 2000 Feb 1;28(3):669-77
references: 10637317
references: Free Radic Biol Med. 2006 May 1;40(9):1578-91
references: 16632118
references: Nat Genet. 1999 Feb;21(2):220-4
references: 9988278
references: Leukemia. 2003 Oct;17(10):2007-15
references: 14513051
references: Nat Rev Cancer. 2009 Aug;9(8):537-49
references: 19629069
references: Mutat Res. 2004 Nov 2;555(1-2):191-202
references: 15476860
references: Methods. 2001 Dec;25(4):402-8
references: 11846609
references: Acta Pharmacol Sin. 2009 May;30(5):501-12
references: 19417730
references: Curr Drug Metab. 2002 Jun;3(3):233-55
references: 12083319
references: Br J Cancer. 2000 Jun;82(11):1819-26
references: 10839297
references: Apoptosis. 2006 May;11(5):789-98
references: 16554963
references: Ann N Y Acad Sci. 2007 Oct;1114:56-68
references: 17934056
references: DNA Repair (Amst). 2006 Feb 3;5(2):145-52
references: 15878696
references: Environ Mol Mutagen. 2009 Apr;50(3):190-200
references: 19177499
references: Toxicol Lett. 2004 Jan 15;146(2):103-9
references: 14643962
references: Nature. 1970 Aug 15;227(5259):680-5
references: 5432063
references: Cancer Lett. 2010 Sep 28;295(2):260-6
references: 20451318
references: Leukemia. 2002 Jun;16(6):1112-20
references: 12040441
references: Anal Biochem. 1976 May 7;72:248-54
references: 942051
references: Biofactors. 2003;17(1-4):287-96
references: 12897450
references: Eur J Cancer. 1997 Apr;33(5):787-91
references: 9282118
references: Proc Natl Acad Sci U S A. 2005 Jun 7;102(23):8222-7
references: 15928077
references: Mutat Res. 2010 Jun 1;688(1-2):72-7
references: 20363232
references: Oncogene. 1999 Feb 4;18(5):1219-26
references: 10022128
references: Oncogene. 2004 Apr 12;23(16):2838-49
references: 15077147
references: J Biol Chem. 2001 Jul 27;276(30):28546-53
references: 11352915
references: Cell Mol Life Sci. 2003 Jul;60(7):1489-503
references: 12943235
references: Drug Metab Rev. 2004 Oct;36(3-4):655-67
references: 15554241
references: J Nutr. 1999 Mar;129(3):768S-774S
references: 10082787
references: J Biol Chem. 2006 Sep 1;281(35):25588-600
references: 16785237
references: Mol Cell Biol. 2005 Sep;25(18):8037-43
references: 16135795
references: Prog Liver Dis. 1986;8:33-50
references: 3520663
references: Cancer Res. 1982 Nov;42(11):4519-24
references: 6290039
references: Environ Mol Mutagen. 2009 Apr;50(3):164-70
references: 19253337
references: J Nutr Biochem. 2010 Sep;21(9):818-26
references: 19733043
references: Age (Dordr). 2012 Apr;34(2):281-93
references: 21465338
references: Cell Biol Int. 2000;24(10):757-60
references: 11023655
references: Biochem Biophys Res Commun. 2012 Apr 27;421(1):91-7
references: 22487794
references: Cancer Lett. 2002 Apr 25;178(2):187-97
references: 11867204
references: Cell Signal. 2008 Jan;20(1):50-9
references: 17881189
references: Cancer Res. 2000 Apr 15;60(8):2116-21
references: 10786671
references: Mol Cell Biochem. 2009 Oct;330(1-2):9-22
references: 19363674
references: Apoptosis. 2012 Sep;17(9):964-74
references: 22684843
references: Oncogene. 2006 Aug 3;25(33):4505-14
references: 16619047
references: J Agric Food Chem. 2011 Oct 26;59(20):10955-63
references: 21928849
references: Cancer Res. 1982 Sep;42(9):3858-63
references: 6286115
references: Cancer Res. 2002 Aug 15;62(16):4575-8
references: 12183409
references: Cancer Res. 1999 Feb 1;59(3):551-7
references: 9973199
references: J Environ Pathol Toxicol Oncol. 2009;28(4):269-82
references: 20102325
references: Anal Biochem. 1981 Apr;112(2):195-203
references: 6266278
references: FASEB J. 2003 Apr;17(6):767-9
references: 12594176
references: Planta Med. 2008 Oct;74(13):1570-9
references: 18671201
references: Forum Nutr. 2009;61:170-181
references: 19367121
references: PLoS One. 2010 Jul 06;5(7):e11457
references: 20625516