title: The antineoplastic drug, trastuzumab, dysregulates metabolism in iPSC-derived cardiomyocytes.
abstract: BACKGROUND
  The targeted ERBB2 therapy, trastuzumab, has had a tremendous impact on management of patients with HER2+ breast cancer, leading to development and increased use of further HER2 targeted therapies. The major clinical side effect is cardiotoxicity but the mechanism is largely unknown. On the basis that gene expression is known to be altered in multiple models of heart failure, we examined differential gene expression of iPSC-derived cardiomyocytes treated at day 11 with the ERBB2 targeted monoclonal antibody, trastuzumab for 48 h and the small molecule tyrosine kinase inhibitor of EGFR and ERBB2.
  
  
  RESULTS
  Transcriptome sequencing was performed on four replicates from each group (48 h untreated, 48 h trastuzumab and 48 h lapatinib) and differential gene expression analyses were performed on each treatment group relative to untreated cardiomyocytes. 517 and 1358 genes were differentially expressed, p < 0.05, respectively in cardiomyocytes treated with trastuzumab and lapatinib. Gene ontology analyses revealed in cardiomyocytes treated with trastuzumab, significant down-regulation of genes involved in small molecule metabolism (p = 3.22 × 10-9) and cholesterol (p = 0.01) and sterol (p = 0.03) processing. We next measured glucose uptake and lactate production in iPSC-derived cardiomyocytes 13 days post-plating, treated with trastuzumab up to 96 h. We observed significantly decreased glucose uptake from the media of iPSC-derived cardiomyocytes treated with trastuzumab as early as 24 h (p = 0.001) and consistently up to 96 h (p = 0.03).
  
  
  CONCLUSIONS
  Our study suggests dysregulation of cardiac gene expression and metabolism as key elements of ERBB2 signaling that could potentially be early biomarkers of cardiotoxicity.
authors.affiliation: Department of Cancer Biology, Mayo Clinic, Jacksonville, FL, USA.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Necela
authors.affiliation: Department of Cancer Biology, Mayo Clinic, Jacksonville, FL, USA.
authors.forename: Bianca C
authors.initials: BC
authors.lastname: Axenfeld
authors.affiliation: Department of Health Sciences Research, Mayo Clinic, Jacksonville, FL, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Serie
authors.affiliation: Department of Cancer Biology, Mayo Clinic, Jacksonville, FL, USA.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Kachergus
authors.affiliation: Department of Hematology Oncology, Mayo Clinic, Jacksonville, FL, USA.
authors.forename: Edith A
authors.initials: EA
authors.lastname: Perez
authors.affiliation: Department of Cancer Biology, Mayo Clinic, Jacksonville, FL, USA.
authors.forename: E Aubrey
authors.initials: EA
authors.lastname: Thompson
authors.affiliation: Department of Cancer Biology, Mayo Clinic, Jacksonville, FL, USA. Norton.nadine@mayo.edu.
authors.forename: Nadine
authors.identifier: http://orcid.org/0000-0002-3848-4288
authors.initials: N
authors.lastname: Norton