title: Combined targeting of mTOR and c-MET signaling pathways for effective management of epithelioid sarcoma.
abstract: BACKGROUND
  Epithelioid sarcoma (EpS) is a high-grade malignant soft-tissue sarcoma characterized by local recurrences and distant metastases. Effective treatments for EpS have not been established and thus novel therapeutic approaches against EpS are urgently required. mTOR inhibitors exert antitumor effects on several malignancies but AKT reactivation by mTOR inhibition attenuates the antitumor effects of mTOR inhibitors. This reactivation is receptor tyrosine kinase (RTK)-dependent due to a release of negative feedback inhibition. We found that c-MET was the most highly activated RTK in two human EpS cell lines, Asra-EPS and VAESBJ. Here we investigated the functional and therapeutic relevance of mTOR and/or c-MET signaling pathways in EpS both in vitro and in vivo.
  
  
  METHODS
  We first examined the effects of an mTOR inhibitor, RAD001 (everolimus), on cell proliferation, cell cycle, AKT/mTOR signaling, and xenograft tumor growth in EpS cell lines. Next, we determined whether RAD001-induced AKT reactivation was blocked by silencing of c-MET or treatment with a selective c-MET inhibitor, INC280. Finally, we evaluated the antitumor effects of RAD001 combined with INC280 on EpS cell lines compared with either single agent or control in vitro and in vivo.
  
  
  RESULTS
  Constitutive AKT phosphorylation was observed in Asra-EPS and VAESBJ cells. RAD001 suppressed EpS cell growth by inducing cell cycle arrest but enhanced AKT phosphorylation, which resulted in intrinsic resistance to mTOR inhibitors. In both EpS cell lines, RAD001-induced AKT phosphorylation was dependent on c-MET signaling. INC280 inhibited phosphorylation of c-MET and its downstream molecules, and decreased RAD001-induced phosphorylation of both AKT and ERK in EpS. Compared with a single agent or control, the combination of RAD001 and INC280 exerted superior antitumor effects on the growth of EpS cell lines in vitro and in vivo.
  
  
  CONCLUSIONS
  Targeting of mTOR and c-MET signaling pathways significantly abrogates the growth of EpS in preclinical models and may be a promising therapeutic approach for patients with EpS.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Imura
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Yasui
authors.forename: Hidetatsu
authors.initials: H
authors.lastname: Outani
authors.forename: Toru
authors.initials: T
authors.lastname: Wakamatsu
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Hamada
authors.forename: Takaaki
authors.initials: T
authors.lastname: Nakai
authors.forename: Shutaro
authors.initials: S
authors.lastname: Yamada
authors.forename: Akira
authors.initials: A
authors.lastname: Myoui
authors.forename: Nobuhito
authors.initials: N
authors.lastname: Araki
authors.forename: Takafumi
authors.initials: T
authors.lastname: Ueda
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Itoh
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan. nnaka@ort.med.osaka-u.ac.jp.
authors.forename: Norifumi
authors.initials: N
authors.lastname: Naka
mesh_terms: D000368:Aged; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology / Q000627:therapeutic use*; D019898:Autocrine Communication / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D000068338:Everolimus; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005260:Female; D017228:Hepatocyte Growth Factor / Q000378:metabolism; D006801:Humans; D008297:Male; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008875:Middle Aged; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D019859:Proto-Oncogene Proteins c-met / Q000037:antagonists & inhibitors* / Q000378:metabolism; D012509:Sarcoma / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology*; D015398:Signal Transduction / Q000187:drug effects; D020123:Sirolimus / Q000031:analogs & derivatives / Q000494:pharmacology / Q000627:therapeutic use; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D017228:Hepatocyte Growth Factor; D000068338:Everolimus; D019859:Proto-Oncogene Proteins c-met; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D020123:Sirolimus
references.citation: Cell. 1998 Oct 2;95(1):29-39
references.pmid: 9778245
references.citation: Cancer Res. 2005 May 15;65(10):4012-9
references.pmid: 15899790
references.citation: Am J Surg Pathol. 1985 Apr;9(4):241-63
references.pmid: 4014539
references.citation: Cancer Res. 2012 Sep 1;72(17):4537-50
references.pmid: 22738909
references.citation: Nature. 2001 May 17;411(6835):355-65
references.pmid: 11357143
references.citation: Mol Cancer Ther. 2013 Jun;12(6):1060-72
references.pmid: 23576573
references.citation: Oncogene. 1997 Oct 2;15(14):1635-42
references.pmid: 9349496
references.citation: Cancer Res. 2012 Aug 1;72(15):3828-38
references.pmid: 22617325
references.citation: J Clin Invest. 2007 Mar;117(3):730-8
references.pmid: 17290308
references.citation: Cancer Res. 2006 Feb 1;66(3):1500-8
references.pmid: 16452206
references.citation: Clin Cancer Res. 2011 Sep 15;17(18):5901-12
references.pmid: 21821699
references.citation: J Clin Oncol. 2013 Jul 1;31(19):2485-92
references.pmid: 23715582
references.citation: Clin Cancer Res. 2011 Nov 15;17(22):7127-38
references.pmid: 21918175
references.citation: Mayo Clin Proc. 1996 Jul;71(7):636-42
references.pmid: 8656704
references.citation: Clin Cancer Res. 2012 Mar 15;18(6):1777-89
references.pmid: 22422409
references.citation: J Clin Oncol. 2013 Feb 1;31(4):412-9
references.pmid: 23169517
references.citation: Cancer Res. 2001 Aug 1;61(15):5911-8
references.pmid: 11479233
references.citation: PLoS Med. 2008 Jan 22;5(1):e8
references.pmid: 18215105
references.citation: Pathol Int. 1998 Oct;48(10):757-62
references.pmid: 9788258
references.citation: J Clin Oncol. 2012 Jan 1;30(1):78-84
references.pmid: 22067397
references.citation: Mol Cancer Ther. 2009 Feb;8(2):376-85
references.pmid: 19190120
references.citation: Cancer Res. 2010 Jan 15;70(2):639-45
references.pmid: 20068147
references.citation: Cancer Chemother Pharmacol. 2009 Apr;63(5):783-91
references.pmid: 18641990
references.citation: Clin Cancer Res. 2011 Jun 15;17(12):3943-55
references.pmid: 21540237
references.citation: EXS. 1995;74:89-121
references.pmid: 8527903
references.citation: Nat Rev Cancer. 2002 Jul;2(7):489-501
references.pmid: 12094235
references.citation: Biochem J. 2007 Aug 15;406(1):57-66
references.pmid: 17506723
references.citation: J Clin Invest. 2008 Sep;118(9):3065-74
references.pmid: 18725988
references.citation: J Biol Chem. 2002 Jul 12;277(28):25203-8
references.pmid: 11994287
references.citation: Cancer. 1970 Nov;26(5):1029-41
references.pmid: 5476785
references.citation: Mol Cell Biol. 1997 Mar;17(3):1595-606
references.pmid: 9032287
references.citation: J Pathol. 2007 Feb;211(3):323-30
references.pmid: 17152049
references.citation: Ann Surg Oncol. 2000 Apr;7(3):218-25
references.pmid: 10791853
references.citation: Nature. 1998 Jul 9;394(6689):203-6
references.pmid: 9671307
references.citation: Cancer Res. 2012 Sep 1;72(17):4515-25
references.pmid: 22787122
references.citation: Int J Oncol. 1995 Jul;7(1):51-6
references.pmid: 21552805
references.citation: Oncogene. 2014 Jun 5;33(23):3024-32
references.pmid: 23851500
references.citation: Cancer Res. 2003 Nov 15;63(22):7926-35
references.pmid: 14633723
references.citation: Cell. 1995 Jun 2;81(5):727-36
references.pmid: 7774014
references.citation: Am J Surg Pathol. 2009 Apr;33(4):542-50
references.pmid: 19033866
references.citation: Oncogene. 1995 Feb 16;10(4):739-49
references.pmid: 7862451
references.citation: Virchows Arch. 1998 Apr;432(4):337-42
references.pmid: 9565343
references.citation: Nat Rev Mol Cell Biol. 2003 Dec;4(12):915-25
references.pmid: 14685170
references.citation: Cancer. 2006 Aug 1;107(3):606-12
references.pmid: 16804932
references.citation: PLoS One. 2012;7(3):e33379
references.pmid: 22428038
references.citation: J Clin Oncol. 2011 Aug 20;29(24):3307-15
references.pmid: 21768463
references.citation: BMC Res Notes. 2013 Aug 01;6:305
references.pmid: 23915498