• Open Access

Radiosensitization of glioma cells by modulation of Met signalling with the hepatocyte growth factor neutralizing antibody, AMG102

Authors

  • Ian M. Buchanan,

    1. Radiation Oncology Branch, National Cancer Institute, Bethesda, MD, USA
    2. Howard Hughes Medical Institute-National Institutes of Health, Research Scholars Program, Bethesda, MD, USA
    3. The Warren Alpert Medical School of Brown University, Providence, RI, USA
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  • Tamalee Scott,

    1. Radiation Oncology Branch, National Cancer Institute, Bethesda, MD, USA
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  • Anita T. Tandle,

    1. Radiation Oncology Branch, National Cancer Institute, Bethesda, MD, USA
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  • William E. Burgan,

    1. Molecular Radiation Therapeutics Branch & Science Applications International Corporation-Frederick, National Cancer Institute-Frederick, Frederick, MD, USA
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  • Teresa L. Burgess,

    1. Amgen, Inc., Thousand Oaks, CA, USA
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  • Philip J. Tofilon,

    1. Drug Discovery Program, H. Lee Moffitt Cancer Center, Tampa, FL, USA
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  • Kevin Camphausen

    Corresponding author
    1. Radiation Oncology Branch, National Cancer Institute, Bethesda, MD, USA
      Kevin CAMPHAUSEN, M.D., Radiation Oncology Branch, National Cancer Institute, 10 Center Drive B2-3561, Bethesda, MD 20892, USA. Tel.: 301-496-5457 Fax: 301-480-5439 E-mail: camphauk@mail.nih.gov
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Kevin CAMPHAUSEN, M.D., Radiation Oncology Branch, National Cancer Institute, 10 Center Drive B2-3561, Bethesda, MD 20892, USA. Tel.: 301-496-5457 Fax: 301-480-5439 E-mail: camphauk@mail.nih.gov

Abstract

The hepatocyte growth factor (HGF)/Met signalling pathway is up-regulated in many cancers, with downstream mediators playing a role in DNA double strand break repair. Previous studies have shown increased radiosensitization of tumours through modulation of Met signalling by genetic methods. We investigated the effects of the anti-HGF monoclonal antibody, AMG102, on the response to ionizing radiation in a model of glioblastoma multiforme in vitro and in vivo. Radiosensitivity was evaluated in vitro in the U-87 MG human glioma cell line. Met activation was measured by Western blot, and the effect on survival following radiation was evaluated by clonogenic assay. Mechanism of cell death was evaluated by apoptosis and mitotic catastrophe assays. DNA damage was quantitated by γH2AX foci and neutral comet assay. Growth kinetics of subcutaneous tumours was used to assess the effects of AMG102 on in vivo tumour radiosensitivity. AMG102 inhibited Met activation after irradiation. An enhancement of radiation cell killing was shown with no toxicity using drug alone. Retention of γH2AX foci at 6 and 24 hrs following the drug/radiation combination indicated an inhibition of DNA repair following radiation, and comet assay confirmed DNA damage persisting over the same duration. At 48 and 72 hrs following radiation, a significant increase of cells undergoing mitotic catastrophe was seen in the drug/radiation treated cells. Growth of subcutaneous tumours was slowed in combination treated mice, with an effect that was greater than additive for each modality individually. Modulation of Met signalling with AMG102 may prove a novel radiation sensitizing strategy. Our data indicate that DNA repair processes downstream of Met are impaired leading to increased cell death through mitotic catastrophe.

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