Synergism from combined immunologic and pharmacologic inhibition of HER2 in vivo.

Journal Article (Journal Article)

The monoclonal antibody trastuzumab and the EGFR/HER2 tyrosine kinase inhibitor lapatinib improve the clinical outcome of patients with HER2-overexpressing breast cancer. However, the majority of metastatic cancers will eventually progress, suggesting the need for other therapies. Because HER2 overexpression persists, we hypothesized that the anti-HER2 immune response induced by cancer vaccines would be an effective strategy for treating trastuzumab- and lapatinib-refractory tumors. Furthermore, we hypothesized that the antibody response could synergize with lapatinib to enhance tumor inhibition. We developed a recombinant adenoviral vector expressing a kinase-inactive HER2 (Ad-HER2-ki) to use as a cancer vaccine. Vaccine-induced polyclonal HER2-specific antiserum was analyzed for receptor internalization and signaling effects alone and in combination with lapatinib. Ad-HER2-ki vaccine-induced potent T cell and antibody responses in mice and the vaccine-induced polyclonal HER2-specific antiserum mediated receptor internalization and degradation much more effectively than trastuzumab. Our in vitro studies demonstrated that HER2 vaccine-induced antibodies effectively caused a decrease in HER2 expression, but when combined with lapatinib caused significant inhibition of HER2 signaling, decreased pERK and pAKT levels and reduced breast tumor cell proliferation. In addition, a known mechanism of resistance to lapatinib, induction of survivin, was inhibited. The combination of Ad-HER2-ki plus lapatinib also showed superior antitumor efficacy in vivo. Based on these results, we feel clinical studies using this approach to target HER2-overexpressing breast cancer, including trastuzumab- and lapatinib-resistant tumors is warranted.

Full Text

Duke Authors

Cited Authors

  • Morse, MA; Wei, J; Hartman, Z; Xia, W; Ren, X-R; Lei, G; Barry, WT; Osada, T; Hobeika, AC; Peplinski, S; Jiang, H; Devi, GR; Chen, W; Spector, N; Amalfitano, A; Lyerly, HK; Clay, TM

Published Date

  • June 15, 2010

Published In

Volume / Issue

  • 126 / 12

Start / End Page

  • 2893 - 2903

PubMed ID

  • 19856307

Pubmed Central ID

  • PMC2856803

Electronic International Standard Serial Number (EISSN)

  • 1097-0215

Digital Object Identifier (DOI)

  • 10.1002/ijc.24995


  • eng

Conference Location

  • United States