Alexandra Matzke-Ogi1, Katharina Jannasch2, Marine Shatirishvili3, Beatrix Fuchs3, Sara Chiblak4, Jennifer Morton5, Bouchra Tawk4, Thomas Lindner6, Owen Sansom5, Frauke Alves2, Arne Warth7, Christian Schwager4, Walter Mier6, Jörg Kleeff8, Helmut Ponta9, Amir Abdollahi4, Véronique Orian-Rousseau10. 1. Karlsruhe Institute of Technology, Institute of Toxicology and Genetics, Eggenstein-Leopoldshafen, Germany; Amcure GmbH, Eggenstein-Leopoldshafen, Germany. 2. Department of Hematology and Oncology, University Medicine Göttingen, Göttingen, Germany. 3. Karlsruhe Institute of Technology, Institute of Toxicology and Genetics, Eggenstein-Leopoldshafen, Germany. 4. Molecular and Translational Radiation Oncology, Heidelberg Institute of Radiation Oncology, University of Heidelberg Medical School and German Cancer Research Center, Heidelberg, Germany; The German Cancer Consortium, Heidelberg, Germany. 5. Cancer Research UK Beatson Institute, Glasgow, United Kingdom. 6. Department of Nuclear Medicine, University of Heidelberg, Heidelberg, Germany. 7. Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany. 8. Department of Surgery, Technische Universität München, Munich, Germany. 9. Amcure GmbH, Eggenstein-Leopoldshafen, Germany. 10. Karlsruhe Institute of Technology, Institute of Toxicology and Genetics, Eggenstein-Leopoldshafen, Germany. Electronic address: veronique.orian-rousseau@kit.edu.
Abstract
BACKGROUND & AIMS: Cancer cells with high metastatic potential and stem cell-like characteristics express the cell surface marker CD44. CD44 isoforms that include the v6 exon are co-receptors for the receptor tyrosine kinases MET and Vascular Endothelial Growth factor Receptor-2 (VEGFR-2). We studied CD44v6 signaling in several pancreatic cancer cell lines, and its role in tumor growth and metastasis in several models of pancreatic cancer. METHODS: We analyzed the effects of v6 peptides that interfere with the co-receptor functions of CD44v6 for MET and VEGFR-2 in tumors and metastases grown from cells that express different CD44 isoforms, including CD44v6. The peptides were injected into rats with syngeneic tumors and mice with orthotopic or xenograft tumors. We also tested the effects of the peptides in mice with xenograft tumors grown from patient tumor samples and mice that express an oncogenic form of RAS and develop spontaneous pancreatic cancer (KPC mice). We measured levels of CD44v6 messenger RNA (mRNA) in pancreatic cancer tissues from 136 patients. RESULTS: Xenograft tumors grown from human cancer cells injected with v6 peptides were smaller and formed fewer metastases in mice. The v6 peptide was more efficient than the MET inhibitor crizotinib and/or the VEGFR-2 inhibitor pazopanib in reducing xenograft tumor growth and metastasis. Injection of KPC mice with the v6 peptide increased their survival time. Injection of mice and rats bearing metastases with the v6 peptide induced regression of metastases. Higher levels of CD44v6 mRNA in human pancreatic tumor tissues were associated with increased expression of MET, tumor metastasis, and shorter patient survival times. CONCLUSIONS: Peptide inhibitors of CD44v6 isoforms block tumor growth and metastasis in several independent models of pancreatic cancer. The v6 peptides induced regression of metastases. Levels of CD44v6 mRNA are increased, along with those of MET mRNA, in patients with metastatic pancreatic tumors, compared with nonmetastatic tumors; the increased levels correlated with shorter patient survival time.
BACKGROUND & AIMS:Cancer cells with high metastatic potential and stem cell-like characteristics express the cell surface marker CD44. CD44 isoforms that include the v6 exon are co-receptors for the receptor tyrosine kinases MET and Vascular Endothelial Growth factor Receptor-2 (VEGFR-2). We studied CD44v6 signaling in several pancreatic cancer cell lines, and its role in tumor growth and metastasis in several models of pancreatic cancer. METHODS: We analyzed the effects of v6 peptides that interfere with the co-receptor functions of CD44v6 for MET and VEGFR-2 in tumors and metastases grown from cells that express different CD44 isoforms, including CD44v6. The peptides were injected into rats with syngeneic tumors and mice with orthotopic or xenograft tumors. We also tested the effects of the peptides in mice with xenograft tumors grown from patienttumor samples and mice that express an oncogenic form of RAS and develop spontaneous pancreatic cancer (KPC mice). We measured levels of CD44v6 messenger RNA (mRNA) in pancreatic cancer tissues from 136 patients. RESULTS:Xenograft tumors grown from humancancer cells injected with v6 peptides were smaller and formed fewer metastases in mice. The v6 peptide was more efficient than the MET inhibitor crizotinib and/or the VEGFR-2 inhibitor pazopanib in reducing xenograft tumor growth and metastasis. Injection of KPC mice with the v6 peptide increased their survival time. Injection of mice and rats bearing metastases with the v6 peptide induced regression of metastases. Higher levels of CD44v6 mRNA in humanpancreatic tumor tissues were associated with increased expression of MET, tumor metastasis, and shorter patient survival times. CONCLUSIONS: Peptide inhibitors of CD44v6 isoforms block tumor growth and metastasis in several independent models of pancreatic cancer. The v6 peptides induced regression of metastases. Levels of CD44v6 mRNA are increased, along with those of MET mRNA, in patients with metastatic pancreatic tumors, compared with nonmetastatic tumors; the increased levels correlated with shorter patient survival time.