title: TNFα-Induced Mucin 4 Expression Elicits Trastuzumab Resistance in HER2-Positive Breast Cancer.
abstract: OBJECTIVE
  Although trastuzumab administration improved the outcome of HER2-positive breast cancer patients, resistance events hamper its clinical benefits. We demonstrated that TNFα stimulation in vitro induces trastuzumab resistance in HER2-positive breast cancer cell lines. Here, we explored the mechanism of TNFα-induced trastuzumab resistance and the therapeutic strategies to overcome it.
  
  
  METHODS
  Trastuzumab-sensitive breast cancer cells, genetically engineered to stably overexpress TNFα, and de novo trastuzumab-resistant tumors, were used to evaluate trastuzumab response and TNFα-blocking antibodies effectiveness respectively. Immunohistochemistry and antibody-dependent cell cytotoxicity (ADCC), together with siRNA strategy, were used to explore TNFα influence on the expression and function of its downstream target, mucin 4 (MUC4). The clinical relevance of MUC4 expression was studied in a cohort of 78 HER2-positive breast cancer patients treated with adjuvant trastuzumab.
  
  
  RESULTS
  TNFα overexpression turned trastuzumab-sensitive cells and tumors into resistant ones. Histopathologic findings revealed mucin foci in TNFα-producing tumors. TNFα induced upregulation of MUC4 that reduced trastuzumab binding to its epitope and impaired ADCC. Silencing MUC4 enhanced trastuzumab binding, increased ADCC, and overcame trastuzumab and trastuzumab-emtansine antiproliferative effects in TNFα-overexpressing cells. Accordingly, administration of TNFα-blocking antibodies downregulated MUC4 and sensitized de novo trastuzumab-resistant breast cancer cells and tumors to trastuzumab. In HER2-positive breast cancer samples, MUC4 expression was found to be an independent predictor of poor disease-free survival (P = 0.008).
  
  
  CONCLUSIONS
  We identified TNFα-induced MUC4 expression as a novel trastuzumab resistance mechanism. We propose MUC4 expression as a predictive biomarker of trastuzumab efficacy and a guide to combination therapy of TNFα-blocking antibodies with trastuzumab. Clin Cancer Res; 23(3); 636-48. ©2016 AACR.
authors.affiliation: Laboratorio de Mecanismos Moleculares de Carcinogénesis, Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina.
authors.forename: María F
authors.initials: MF
authors.lastname: Mercogliano
authors.affiliation: Laboratorio de Mecanismos Moleculares de Carcinogénesis, Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina.
authors.forename: Mara
authors.initials: M
authors.lastname: De Martino
authors.affiliation: Laboratorio de Mecanismos Moleculares de Carcinogénesis, Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina.
authors.forename: Leandro
authors.initials: L
authors.lastname: Venturutti
authors.affiliation: Department of Medicine, Weill Cornell Medical College, New York, New York.
authors.forename: Martín A
authors.initials: MA
authors.lastname: Rivas
authors.affiliation: Laboratorio de Mecanismos Moleculares de Carcinogénesis, Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina.
authors.forename: Cecilia J
authors.initials: CJ
authors.lastname: Proietti
authors.affiliation: Servicio de Patología, Sanatorio Mater Dei, Buenos Aires, Argentina.
authors.forename: Gloria
authors.initials: G
authors.lastname: Inurrigarro
authors.affiliation: Servicio de Patología, Sanatorio Mater Dei, Buenos Aires, Argentina.
authors.forename: Isabel
authors.initials: I
authors.lastname: Frahm
authors.affiliation: Unidad de Patología Mamaria, Hospital General de Agudos "Juan A. Fernández," Buenos Aires, Argentina.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Allemand
authors.affiliation: Instituto Oncológico Henry Moore, Buenos Aires, Argentina.
authors.forename: Ernesto Gil
authors.initials: EG
authors.lastname: Deza
authors.affiliation: Instituto Oncológico Henry Moore, Buenos Aires, Argentina.
authors.forename: Sandra
authors.initials: S
authors.lastname: Ares
authors.affiliation: Instituto Oncológico Henry Moore, Buenos Aires, Argentina.
authors.forename: Felipe G
authors.initials: FG
authors.lastname: Gercovich
authors.affiliation: Departamento de Anatomía Patológica (BIOREN), Universidad de La Frontera, Temuco, Chile.
authors.forename: Pablo
authors.initials: P
authors.lastname: Guzmán
authors.affiliation: Departamento de Anatomía Patológica (BIOREN), Universidad de La Frontera, Temuco, Chile.|Department of Pathology. Advanced Center for Chronic Diseases (ACCDIS), Pontificia Universidad Catolica de Chile, Santiago de Chile, Chile.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Roa
authors.affiliation: Laboratorio de Mecanismos Moleculares de Carcinogénesis, Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina.
authors.forename: Patricia V
authors.initials: PV
authors.lastname: Elizalde
authors.affiliation: Laboratorio de Mecanismos Moleculares de Carcinogénesis, Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina. roxanaschillaci@gmail.com rschillaci@ibyme.conicet.gov.ar.
authors.forename: Roxana
authors.initials: R
authors.lastname: Schillaci
mesh_terms: D000080044:Ado-Trastuzumab Emtansine; D000818:Animals; D000920:Antibody-Dependent Cell Cytotoxicity; D000074322:Antineoplastic Agents, Immunological / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D045744:Cell Line, Tumor; D018572:Disease-Free Survival; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000502:physiology*; D004357:Drug Synergism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D018796:Immunoconjugates / Q000494:pharmacology; D008453:Maytansine / Q000031:analogs & derivatives / Q000494:pharmacology; D051379:Mice; D008819:Mice, Nude; D055264:Mucin-4 / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D009363:Neoplasm Proteins / Q000032:analysis* / Q000037:antagonists & inhibitors; D034622:RNA Interference; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis* / Q000037:antagonists & inhibitors; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013274:Stomach Neoplasms / Q000473:pathology; D000068878:Trastuzumab / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D015854:Up-Regulation / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D000080044:Ado-Trastuzumab Emtansine; D000074322:Antineoplastic Agents, Immunological; D018796:Immunoconjugates; D008453:Maytansine; D055264:Mucin-4; D009363:Neoplasm Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; D000068878:Trastuzumab; D014409:Tumor Necrosis Factor-alpha; C524658:MUC4 protein, human; C508053:ERBB2 protein, human