Visualizing the dynamics of EGFR activity and antiglioma therapies in vivo.

Abstract

Many altered pathways in cancer cells depend on growth factor receptors. In primary malignant gliomas, the amplification/alteration of the epidermal growth factor receptor (EGFR) has been shown to play a significant role in enhancing glioma burden. In an effort to dissect the role of EGFR expression in glioma progression in vivo and evaluate targeted therapies for gliomas, we have genetically engineered glioma cells to visualize the dynamics of EGFR and targeted therapies in real time in vivo. Using engineered lentiviral vectors bearing fusions between EGFR and its exon 2 to 7 deleted variant (EGFRvIII) with green fluorescent protein (GFP) and Renilla luciferase (Rluc), we show that there is a direct correlation between EGFR expression and glioma cell proliferation in the initial stages of glioma progression. To monitor and evaluate EGFR-targeted therapies, we have engineered (a) short hairpin RNAs (shRNA) and (b) clinically used monoclonal antibody, cetuximab. Using EGFR-GFP-Rluc/firefly luciferase (Fluc)-DsRed2 glioma model, we show that both shRNAs and cetuximab result in a considerable reduction in glioma cell proliferation in culture and glioma burden in vivo that can be monitored in real time at a cellular resolution. This study serves as a template to follow the role of growth factor receptor expression in tumor progression and to image therapeutic efficacy of targeted therapies in cancer.

• Authors: Esther Arwert, Shawn Hingtgen, Jose-Luiz Figueiredo, Henry Bergquist, Umar Mahmood, Ralph Weissleder, Khalid Shah
• Journal: Cancer research (Cancer Res) Vol. 67 Issue 15 Pg. 7335-42 (Aug 01 2007) ISSN: 0008-5472 [Print] United States
• PMID: 17671203 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies, Monoclonal
• Antibodies, Monoclonal, Humanized
• RNA, Small Interfering
• epidermal growth factor receptor VIII
• ErbB Receptors
• Cetuximab

Topics

• Animals
• Antibodies, Monoclonal (therapeutic use)
• Antibodies, Monoclonal, Humanized
• Blotting, Western
• Brain Neoplasms (genetics, immunology, therapy)
• Cell Proliferation
• Cetuximab
• Combined Modality Therapy
• ErbB Receptors (antagonists & inhibitors, genetics, immunology)
• Flow Cytometry
• Genetic Engineering
• Genetic Therapy
• Glioma (genetics, immunology, therapy)
• Humans
• Lentivirus (genetics)
• Mice
• Mice, Nude
• RNA Interference
• RNA, Small Interfering (therapeutic use)
• Tumor Cells, Cultured