title: Inhibition of Wee1, AKT, and CDK4 underlies the efficacy of the HSP90 inhibitor XL888 in an in vivo model of NRAS-mutant melanoma.
abstract: The HSP90 inhibitor XL888 is effective at reversing BRAF inhibitor resistance in melanoma, including that mediated through acquired NRAS mutations. The present study has investigated the mechanism of action of XL888 in NRAS-mutant melanoma. Treatment of NRAS-mutant melanoma cell lines with XL888 led to an inhibition of growth, G2-M phase cell-cycle arrest, and the inhibition of cell survival in three-dimensional spheroid and colony formation assays. In vitro, HSP90 inhibition led to the degradation of ARAF, CRAF, Wee1, Chk1, and cdc2 and was associated with decreased mitogen-activated protein kinase (MAPK), AKT, mTOR, and c-jun NH2 kinase (JNK) signaling. Apoptosis induction was associated with increased BIM expression and a decrease in the expression of the prosurvival protein Mcl-1. The critical role of increased BIM and decreased Mcl-1 expression in the survival of NRAS-mutant melanoma cell lines was shown through siRNA knockdown and overexpression studies. In an animal xenograft model of NRAS-mutant melanoma, XL888 treatment led to reduced tumor growth and apoptosis induction. Important differences in the pattern of client degradation were noted between the in vivo and in vitro studies. In vivo, XL888 treatment led to degradation of CDK4 and Wee1 and the inhibition of AKT/S6 signaling with little or no effect observed upon ARAF, CRAF, or MAPK. Blockade of Wee1, using either siRNA knockdown or the inhibitor MK1775, was associated with significant levels of growth inhibition and apoptosis induction. Together, these studies have identified Wee1 as a key target of XL888, suggesting novel therapeutic strategies for NRAS-mutant melanoma.
authors.affiliation: Department of Molecular Oncology, The Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA.
authors.forename: H Eirik
authors.initials: HE
authors.lastname: Haarberg
authors.forename: Kim H T
authors.initials: KH
authors.lastname: Paraiso
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Wood
authors.forename: Vito W
authors.initials: VW
authors.lastname: Rebecca
authors.forename: Vernon K
authors.initials: VK
authors.lastname: Sondak
authors.forename: John M
authors.initials: JM
authors.lastname: Koomen
authors.forename: Keiran S M
authors.initials: KS
authors.lastname: Smalley
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053961:Azabicyclo Compounds / Q000008:administration & dosage; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000235:genetics*; D045744:Cell Line, Tumor; D051358:Cyclin-Dependent Kinase 4 / Q000037:antagonists & inhibitors / Q000235:genetics*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000235:genetics; D020558:GTP Phosphohydrolases / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D018841:HSP90 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D006801:Humans; D008545:Melanoma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D058990:Molecular Targeted Therapy; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000235:genetics*; D051058:Oncogene Protein v-akt / Q000037:antagonists & inhibitors / Q000235:genetics*; D010795:Phthalic Acids / Q000008:administration & dosage; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics*; D034741:RNA, Small Interfering; D015398:Signal Transduction / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D053961:Azabicyclo Compounds; D018797:Cell Cycle Proteins; D018841:HSP90 Heat-Shock Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; D010795:Phthalic Acids; D034741:RNA, Small Interfering; C559121:XL 888; D011505:Protein-Tyrosine Kinases; C499349:WEE1 protein, human; D051058:Oncogene Protein v-akt; C495900:CDK4 protein, human; D051358:Cyclin-Dependent Kinase 4; D020558:GTP Phosphohydrolases; C579846:NRAS protein, human
references.citation: Nature. 2006 Jan 19;439(7074):358-62
references.pmid: 16273091
references.citation: Clin Cancer Res. 2008 Jan 1;14(1):230-9
references.pmid: 18172275
references.citation: Pigment Cell Melanoma Res. 2008 Oct;21(5):534-44
references.pmid: 18715233
references.citation: Proc Natl Acad Sci U S A. 1993 Apr 15;90(8):3516-20
references.pmid: 7682708
references.citation: PLoS One. 2011 Mar 07;6(3):e17692
references.pmid: 21408192
references.citation: Nat Rev Cancer. 2010 Aug;10(8):537-49
references.pmid: 20651736
references.citation: Mol Cancer Ther. 2006 May;5(5):1136-44
references.pmid: 16731745
references.citation: Nat Rev Cancer. 2003 Jan;3(1):11-22
references.pmid: 12509763
references.citation: Cancer Res. 2007 Jan 15;67(2):782-91
references.pmid: 17234790
references.citation: Nature. 2012 Mar 28;483(7391):603-7
references.pmid: 22460905
references.citation: Genes Dev. 2012 May 15;26(10):1055-69
references.pmid: 22549727
references.citation: Pigment Cell Melanoma Res. 2011 Aug;24(4):666-72
references.pmid: 21615881
references.citation: PLoS One. 2009 May 27;4(5):e5717
references.pmid: 19492075
references.citation: PLoS One. 2012;7(6):e38254
references.pmid: 22719872
references.citation: J Biol Chem. 2003 May 23;278(21):18811-6
references.pmid: 12646560
references.citation: J Invest Dermatol. 2003 Jun;120(6):1081-6
references.pmid: 12787138
references.citation: Cancer. 2012 Aug 15;118(16):4014-23
references.pmid: 22180178
references.citation: Nat Rev Cancer. 2003 Jun;3(6):459-65
references.pmid: 12778136
references.citation: Semin Oncol. 2012 Apr;39(2):204-14
references.pmid: 22484192
references.citation: Nat Struct Mol Biol. 2011 May;18(5):584-91
references.pmid: 21478863
references.citation: Cancer Res. 2010 Aug 15;70(16):6670-81
references.pmid: 20647317
references.citation: Proc Natl Acad Sci U S A. 2007 Apr 24;104(17):7211-6
references.pmid: 17431037
references.citation: Oncogene. 2004 Jul 8;23(31):5301-15
references.pmid: 15241487
references.citation: Oncogene. 2003 May 19;22(20):3138-51
references.pmid: 12789290
references.citation: Cancer Res. 2006 Oct 1;66(19):9483-91
references.pmid: 17018604
references.citation: Cancer Res. 2005 Dec 1;65(23):10686-91
references.pmid: 16322212
references.citation: Cancer Cell. 2005 Oct;8(4):287-97
references.pmid: 16226704
references.citation: Mol Cell Biol. 1999 Sep;19(9):6195-206
references.pmid: 10454566
references.citation: N Engl J Med. 2011 Jun 30;364(26):2507-16
references.pmid: 21639808
references.citation: Mol Cancer Ther. 2012 Jan;11(1):174-82
references.pmid: 22084170
references.citation: J Cell Sci. 2004 Jun 1;117(Pt 13):2641-51
references.pmid: 15169835
references.citation: Cancer Cell. 2010 Jul 13;18(1):39-51
references.pmid: 20609351
references.citation: Mol Cancer Res. 2009 Apr;7(4):549-56
references.pmid: 19372583
references.citation: Oncogene. 2008 May 22;27(23):3301-12
references.pmid: 18246127
references.citation: Oncogene. 2013 Jun 20;32(25):3009-18
references.pmid: 23069660
references.citation: Proteomics Clin Appl. 2011 Aug;5(7-8):383-96
references.pmid: 21656910
references.citation: Cancer Cell. 2011 Nov 15;20(5):620-34
references.pmid: 22094256
references.citation: Cancer Res. 2011 Apr 1;71(7):2750-60
references.pmid: 21317224
references.citation: Nature. 2010 Sep 30;467(7315):596-9
references.pmid: 20823850
references.citation: Nat Med. 2008 Dec;14(12):1351-6
references.pmid: 19029981
references.citation: Mol Cancer Ther. 2012 Apr;11(4):909-20
references.pmid: 22389471
references.citation: Clin Cancer Res. 2012 May 1;18(9):2502-14
references.pmid: 22351686
references.citation: Br J Cancer. 2007 Feb 12;96(3):445-9
references.pmid: 17245336
references.citation: Nat Med. 2012 Oct;18(10):1503-10
references.pmid: 22983396
references.citation: Proc Natl Acad Sci U S A. 2006 Jan 3;103(1):57-62
references.pmid: 16371460
references.citation: Nat Rev Mol Cell Biol. 2010 Jul;11(7):515-28
references.pmid: 20531426
references.citation: Clin Cancer Res. 2011 May 1;17(9):2799-806
references.pmid: 21389100
references.citation: Cancer Res. 2006 Oct 1;66(19):9636-45
references.pmid: 17018621
references.citation: Cell. 2012 Aug 31;150(5):987-1001
references.pmid: 22939624