Phosphoproteomic mass spectrometry profiling links Src family kinases to escape from HER2 tyrosine kinase inhibition. Academic Article uri icon

Overview

abstract

  • Despite the initial effectiveness of the tyrosine kinase inhibitor lapatinib against HER2 gene-amplified breast cancers, most patients eventually relapse after treatment, implying that tumors acquire mechanisms of drug resistance. To discover these mechanisms, we generated six lapatinib-resistant HER2-overexpressing human breast cancer cell lines. In cells that grew in the presence of lapatinib, HER2 autophosphorylation was undetectable, whereas active phosphoinositide-3 kinase (PI3K)-Akt and mitogen-activated protein kinase (MAPK) were maintained. To identify networks maintaining these signaling pathways, we profiled the tyrosine phosphoproteome of sensitive and resistant cells using an immunoaffinity-enriched mass spectrometry method. We found increased phosphorylation of Src family kinases (SFKs) and putative Src substrates in several resistant cell lines. Treatment of these resistant cells with Src kinase inhibitors partially blocked PI3K-Akt signaling and restored lapatinib sensitivity. Further, SFK mRNA expression was upregulated in primary HER2+ tumors treated with lapatinib. Finally, the combination of lapatinib and the Src inhibitor AZD0530 was more effective than lapatinib alone at inhibiting pAkt and growth of established HER2-positive BT-474 xenografts in athymic mice. These data suggest that increased Src kinase activity is a mechanism of lapatinib resistance and support the combination of HER2 antagonists with Src inhibitors early in the treatment of HER2+ breast cancers in order to prevent or overcome resistance to HER2 inhibitors.

publication date

  • April 18, 2011

Research

keywords

  • Mass Spectrometry
  • Phosphoproteins
  • Protein Kinase Inhibitors
  • Proteomics
  • Receptor, ErbB-2
  • src-Family Kinases

Identity

PubMed Central ID

  • PMC3204390

Scopus Document Identifier

  • 85027940454

Digital Object Identifier (DOI)

  • 10.1038/onc.2011.130

PubMed ID

  • 21499296

Additional Document Info

volume

  • 30

issue

  • 40