The antiepidermal growth factor receptor monoclonal antibody cetuximab C225 reduces hypoxia-inducible factor-1 alpha, leading to transcriptional inhibition of vascular endothelial growth factor expression

• Published in: Oncogene Vol. 24; no. 27; pp. 4433 - 4441
• Main Authors: LUWOR, Rodney B, YANG LU, XINQUN LI, MENDELSOHN, John, ZHEN FAN
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing 23.06.2005; Nature Publishing Group
• Subjects: 1-Phosphatidylinositol 3-kinase; Angiogenesis; Animal models; Antibodies, Monoclonal - immunology; Antibodies, Monoclonal - pharmacology; Antibodies, Monoclonal, Humanized; Antineoplastic Agents - immunology; Antineoplastic Agents - pharmacology; Apoptosis; Biological and medical sciences; Cell culture; Cell cycle; Cell Line, Tumor; Cell physiology; Cell receptors; Cell structures and functions; Cell transformation and carcinogenesis. Action of oncogenes and antioncogenes; Cetuximab; Chromosome 10; Colorectal cancer; Colorectal carcinoma; Epidermal growth factor; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Neoplastic - drug effects; Gene Expression Regulation, Neoplastic - genetics; Humans; Hypoxia; Hypoxia-inducible factor 1; Hypoxia-Inducible Factor 1, alpha Subunit; Hypoxia-inducible factor 1a; Kinases; Lactacystin; Lung cancer; MAP kinase; Metastases; Metastasis; Miscellaneous; Molecular and cellular biology; Molecular genetics; Monoclonal antibodies; Mutation - genetics; Phosphoric Monoester Hydrolases - genetics; Phosphoric Monoester Hydrolases - metabolism; Proteasome inhibitors; Protein biosynthesis; Protein kinase; Proteins; PTEN Phosphohydrolase; PTEN protein; ras Proteins - genetics; ras Proteins - metabolism; Tensin; Transcription; Transcription Factors - metabolism; Transcription, Genetic - drug effects; Transcription. Transcription factor. Splicing. Rna processing; Tumor Suppressor Proteins - genetics; Tumor Suppressor Proteins - metabolism; Tumors; Vascular endothelial growth factor; Vascular Endothelial Growth Factor A - genetics; Vascular Endothelial Growth Factor A - metabolism; Antineoplastic agent; Protein kinase B; Transcription; Ras; PTEN; Esterases; HIF-1α; Monoclonal antibody; Carcinogenesis; Inhibition; Cetuximab; Tumor suppressor gene; G protein; Biological receptor; Oxygen; Enzyme; Triphosphoric monoester hydrolases; VEGF; dGTPase; Akt; Gene expression; Vascular endothelium growth factor; Hydrolases; Hypoxia; EGF receptor; Growth factor
• ISSN: 0950-9232; 1476-5594
• DOI: 10.1038/sj.onc.1208625

We have previously shown that the antiepidermal growth factor receptor monoclonal antibody cetuximab (C225; Erbitux), which was recently approved for the treatment of metastatic colorectal cancer, has antiangiogenic properties, inhibiting vascular endothelial growth factor (VEGF) secretion in culture and in animal models. Here, we have furthered the study by demonstrating that cetuximab reduces cellular levels of hypoxia-inducible factor-1 alpha (HIF-1alpha), a transcriptional regulator of VEGF expression, in A431 epidermoid carcinoma cells under both normoxic and hypoxic culture conditions. Expression of a constitutively active Ras in A431 cells rendered cellular resistance to the cetuximab-mediated reduction of the HIF-1alpha level. Cell lines with naturally occurring phosphatase and tensin homologue deleted on chromosome 10 mutations or deletions were also resistant to cetuximab-mediated reduction of the HIF-1alpha level. Pharmacologic inhibition of phosphatidylinositol 3-kinase with LY294002 reduced the HIF-1alpha level in both normoxic and hypoxic A431 cells, whereas inhibition of the mitogen-activated protein kinase kinase by PD98059 reduced the level of HIF-1alpha only in normoxic A431 cells. In addition, cetuximab reduced the cellular level of HIF-1alpha in the presence of a proteasome inhibitor, lactacystin, indicating that cetuximab acts mainly at the level of protein synthesis. The reduction of HIF-1alpha in response to cetuximab treatment was accompanied by transcriptional inhibition of VEGF expression, measured by a luciferase assay in A431 cells transfected with a vector containing the VEGF hypoxia response element. Taken together, our results indicate that the previously demonstrated inhibition of VEGF by cetuximab occurs at the level of transcription in response to a reduced level of HIF-1alpha and justify further testing of therapeutic strategies that combine cetuximab with approaches inhibiting the function of VEGF or the VEGF receptor.