title: X-linked inhibitor of apoptosis protein mediates tumor cell resistance to antibody-dependent cellular cytotoxicity.
abstract: Inflammatory breast cancer (IBC) is the deadliest, distinct subtype of breast cancer. High expression of epidermal growth factor receptors [EGFR or human epidermal growth factor receptor 2 (HER2)] in IBC tumors has prompted trials of anti-EGFR/HER2 monoclonal antibodies to inhibit oncogenic signaling; however, de novo and acquired therapeutic resistance is common. Another critical function of these antibodies is to mediate antibody-dependent cellular cytotoxicity (ADCC), which enables immune effector cells to engage tumors and deliver granzymes, activating executioner caspases. We hypothesized that high expression of anti-apoptotic molecules in tumors would render them resistant to ADCC. Herein, we demonstrate that the most potent caspase inhibitor, X-linked inhibitor of apoptosis protein (XIAP), overexpressed in IBC, drives resistance to ADCC mediated by cetuximab (anti-EGFR) and trastuzumab (anti-HER2). Overexpression of XIAP in parental IBC cell lines enhances resistance to ADCC; conversely, targeted downregulation of XIAP in ADCC-resistant IBC cells renders them sensitive. As hypothesized, this ADCC resistance is in part a result of the ability of XIAP to inhibit caspase activity; however, we also unexpectedly found that resistance was dependent on XIAP-mediated, caspase-independent suppression of reactive oxygen species (ROS) accumulation, which otherwise occurs during ADCC. Transcriptome analysis supported these observations by revealing modulation of genes involved in immunosuppression and oxidative stress response in XIAP-overexpressing, ADCC-resistant cells. We conclude that XIAP is a critical modulator of ADCC responsiveness, operating through both caspase-dependent and -independent mechanisms. These results suggest that strategies targeting the effects of XIAP on caspase activation and ROS suppression have the potential to enhance the activity of monoclonal antibody-based immunotherapy.
authors.affiliation: Division of Surgical Sciences, Department of Surgery, Duke University Medical Center, Durham, NC, USA.|Department of Pathology, Duke University Medical Center, Durham, NC, USA.
authors.forename: M K
authors.initials: MK
authors.lastname: Evans
authors.affiliation: Division of Surgical Sciences, Department of Surgery, Duke University Medical Center, Durham, NC, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Sauer
authors.affiliation: Division of Surgical Sciences, Department of Surgery, Duke University Medical Center, Durham, NC, USA.
authors.forename: S
authors.initials: S
authors.lastname: Nath
authors.affiliation: Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Robinson
authors.affiliation: Department of Medicine, Duke University Medical Center, Durham, NC, USA.|Duke Cancer Institute, Duke University Medical Center, Durham, NC, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Morse
authors.affiliation: Division of Surgical Sciences, Department of Surgery, Duke University Medical Center, Durham, NC, USA.|Department of Pathology, Duke University Medical Center, Durham, NC, USA.|Duke Cancer Institute, Duke University Medical Center, Durham, NC, USA.
authors.forename: G R
authors.initials: GR
authors.lastname: Devi
mesh_terms: D000920:Antibody-Dependent Cell Cytotoxicity / Q000187:drug effects; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology; D045744:Cell Line, Tumor; D000068818:Cetuximab / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D005260:Female; D055785:Gene Knockdown Techniques; D006801:Humans; D007167:Immunotherapy / Q000379:methods; D058922:Inflammatory Breast Neoplasms / Q000235:genetics / Q000276:immunology* / Q000473:pathology / Q000628:therapy*; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology; D016328:NF-kappa B / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis; D000068878:Trastuzumab / Q000494:pharmacology; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000172:deficiency / Q000235:genetics / Q000276:immunology*
chemical_list: D000068818:Cetuximab; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; D051636:X-Linked Inhibitor of Apoptosis Protein; C496866:XIAP protein, human; C508053:ERBB2 protein, human
references.citation: Cell. 2000 Jul 7;102(1):43-53
references.pmid: 10929712
references.citation: Cell Death Differ. 2010 Jan;17(1):54-60
references.pmid: 19590513
references.citation: Proc Natl Acad Sci U S A. 2005 Oct 25;102(43):15545-50
references.pmid: 16199517
references.citation: Sci Signal. 2012 Mar 20;5(216):ra22
references.pmid: 22434933
references.citation: Br J Cancer. 2007 Sep 3;97(5):659-69
references.pmid: 17700572
references.citation: Cell Death Differ. 2010 Apr;17(4):616-23
references.pmid: 20075940
references.citation: Trends Immunol. 2012 Nov;33(11):535-45
references.pmid: 22836014
references.citation: PLoS One. 2011;6(7):e20659
references.pmid: 21789165
references.citation: Immunol Rev. 2010 May;235(1):105-16
references.pmid: 20536558
references.citation: Clin Cancer Res. 2010 Sep 15;16(18):4496-502
references.pmid: 20682709
references.citation: Int J Cancer. 2009 Feb 1;124(3):511-5
references.pmid: 19003982
references.citation: Cell Mol Immunol. 2009 Feb;6(1):15-25
references.pmid: 19254476
references.citation: Proc Natl Acad Sci U S A. 2006 May 16;103(20):7795-800
references.pmid: 16682622
references.citation: Cancer Chemother Pharmacol. 1997;40(4):321-9
references.pmid: 9225950
references.citation: Cancer Lett. 2013 May 28;332(2):215-24
references.pmid: 22776562
references.citation: Invest Ophthalmol Vis Sci. 2011 Apr;52(5):2640-8
references.pmid: 21212175
references.citation: Arch Biochem Biophys. 1997 Nov 15;347(2):256-62
references.pmid: 9367533
references.citation: Cell Death Differ. 2015 May;22(5):862-74
references.pmid: 25361078
references.citation: Cancer Res. 2009 Mar 1;69(5):1782-91
references.pmid: 19223549
references.citation: Discov Med. 2011 Mar;11(58):221-31
references.pmid: 21447281
references.citation: Cancer Lett. 2013 Aug 28;337(1):77-89
references.pmid: 23689139
references.citation: Nat Biotechnol. 2014 Feb;32(2):182-90
references.pmid: 24463573
references.citation: Semin Cell Dev Biol. 2015 Mar;39:132-8
references.pmid: 25550219
references.citation: Breast Cancer Res Treat. 2013 Jan;137(2):359-71
references.pmid: 23225169
references.citation: J Immunol Res. 2014;2014:923135
references.pmid: 24741632
references.citation: Cancer. 2010 Mar 1;116(5):1234-42
references.pmid: 20082448
references.citation: Genes Dev. 2008 Aug 15;22(16):2256-66
references.pmid: 18708583
references.citation: Int J Cancer. 1994 Sep 15;58(6):763-8
references.pmid: 7927865
references.citation: J Clin Oncol. 2002 Apr 1;20(7):1800-8
references.pmid: 11919237
references.citation: FEBS Lett. 2004 Jul 30;571(1-3):50-4
references.pmid: 15280016
references.citation: J Clin Invest. 1991 Jul;88(1):282-9
references.pmid: 1905328
references.citation: PLoS One. 2013;8(1):e53150
references.pmid: 23341929
references.citation: Eur J Immunol. 1990 Nov;20(11):2445-8
references.pmid: 1701392
references.citation: Mol Cancer Ther. 2012 Jul;11(7):1518-27
references.pmid: 22508521
references.citation: Nat Rev Cancer. 2012 Apr;12(4):252-64
references.pmid: 22437870
references.citation: Breast Cancer Res Treat. 2012 Feb;132(1):109-19
references.pmid: 21559822
references.citation: BMC Biol. 2010;8:7
references.pmid: 20100315
references.citation: Immunity. 2010 Jun 25;32(6):790-802
references.pmid: 20605485
references.citation: Free Radic Biol Med. 2014 Mar;68:302-14
references.pmid: 24334253
references.citation: J Biol Chem. 2009 Aug 7;284(32):21209-17
references.pmid: 19531477
references.citation: Nat Rev Mol Cell Biol. 2001 Jul;2(7):550-6
references.pmid: 11433370
references.citation: Nat Rev Immunol. 2008 May;8(5):362-71
references.pmid: 18379575
references.citation: CA Cancer J Clin. 2010 Nov-Dec;60(6):351-75
references.pmid: 20959401
references.citation: Oxid Med Cell Longev. 2014;2014:646909
references.pmid: 24693337
references.citation: Mol Cancer Ther. 2008 Jan;7(1):38-47
references.pmid: 18202008
references.citation: Immunity. 2003 Mar;18(3):355-65
references.pmid: 12648453
references.citation: Cell Res. 2011 Jan;21(1):103-15
references.pmid: 21187859
references.citation: Mol Cell. 2007 Jun 8;26(5):689-702
references.pmid: 17560374
references.citation: N Engl J Med. 2001 Mar 15;344(11):783-92
references.pmid: 11248153
references.citation: Clin Cancer Res. 2007 Oct 15;13(20):6056-63
references.pmid: 17947468
references.citation: Leuk Lymphoma. 2014 Mar;55(3):645-51
references.pmid: 23697877
references.citation: Trends Immunol. 2004 Dec;25(12):677-86
references.pmid: 15530839
references.citation: Adv Exp Med Biol. 2012;946:135-46
references.pmid: 21948366
references.citation: Nature. 2001 Mar 1;410(6824):112-6
references.pmid: 11242052
references.citation: Mol Cancer Ther. 2004 Jun;3(6):699-707
references.pmid: 15210856
references.citation: J Biol Chem. 2004 Mar 5;279(10):9023-9
references.pmid: 14701799
references.citation: Mol Cancer Ther. 2010 May;9(5):1432-42
references.pmid: 20406946
references.citation: PLoS One. 2014;9(2):e88557
references.pmid: 24551119
references.citation: Science. 2010 May 7;328(5979):749-52
references.pmid: 20339029
references.citation: Front Immunol. 2013 Mar 27;4:76
references.pmid: 23543707
references.citation: Ann Oncol. 2007 Jun;18(6):1021-9
references.pmid: 17351259
references.citation: Biostatistics. 2003 Apr;4(2):249-64
references.pmid: 12925520