Phosphoproteomic mass spectrometry profiling links Src family kinases to escape from HER2 tyrosine kinase inhibition

B. N. Rexer, A. J.L. Ham, C. Rinehart, S. Hill, N. De Matos Granja-Ingram, A. M. González-Angulo, G. B. Mills, B. Dave, J. C. Chang, D. C. Liebler, C. L. Arteaga

    Research output: Contribution to journalArticlepeer-review

    98 Scopus citations

    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.

    Original languageEnglish (US)
    Pages (from-to)4163-4174
    Number of pages12
    JournalOncogene
    Volume30
    Issue number40
    DOIs
    StatePublished - Oct 6 2011

    Keywords

    • HER2
    • Src kinases
    • breast cancer
    • lapatinib
    • tyrosine phosphorylation

    ASJC Scopus subject areas

    • Molecular Biology
    • Genetics
    • Cancer Research

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