Specific roles for the PI3K and the MEK-ERK pathway in IGF-1-stimulated chemotaxis, VEGF secretion and proliferation of multiple myeloma cells: study in the 5T33MM model

• Published in: British journal of cancer Vol. 90; no. 5; pp. 1076 - 1083
• Main Authors: Menu, E, Kooijman, R, Van Valckenborgh, E, Asosingh, K, Bakkus, M, Van Camp, B, Vanderkerken, K
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 08.03.2004
• Subjects: Angiogenesis; Animals; Bone marrow; Cancer research; Cell Division - drug effects; Cell Movement - drug effects; Chemotaxis - drug effects; Disease Models, Animal; Down-Regulation; Experimental Therapeutics; Flavonoids - pharmacology; Hematology; Humans; Immunology; Insulin; Insulin-Like Growth Factor I - pharmacology; Insulin-like growth factors; Medical prognosis; Medical research; Mice; Mice, Inbred C57BL; Mitogen-Activated Protein Kinase 1 - antagonists & inhibitors; Mitogen-Activated Protein Kinase 1 - metabolism; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinase Kinases - metabolism; Mitogen-Activated Protein Kinases - metabolism; Multiple myeloma; Multiple Myeloma - metabolism; Multiple Myeloma - pathology; Neovascularization, Pathologic - metabolism; Phosphatidylinositol 3-Kinases - metabolism; Phosphorylation - drug effects; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins - metabolism; Proto-Oncogene Proteins c-akt; Signal transduction; Signal Transduction - drug effects; Tumor Cells, Cultured; Vascular endothelial growth factor; Vascular Endothelial Growth Factor A - metabolism; Belgium
• ISSN: 0007-0920; 1532-1827
• DOI: 10.1038/sj.bjc.6601613

Insulin-like growth factor-1 (IGF-1) has been described as an important factor in proliferation, cell survival and migration of multiple myeloma (MM) cells. Angiogenesis correlates with development and prognosis of the MM disease. Vascular endothelial growth factor (VEGF) is one of the prominent factors involved in this process. The different functions of IGF-1 were investigated in the 5TMM mouse model with emphasis on proliferation, migration and VEGF secretion, and the signalling pathways involved. Western Blot analysis revealed that ERK1/2 and Akt (PKB) were activated after IGF-1 stimulation. The activation of ERK1/2 was reduced by the PI3K inhibitor Wortmannin, implying that the PI3K pathway is involved in its activation. Insulin-like growth factor-1 induced an increase in DNA synthesis in MM cells, which was mediated by a PI3K/Akt-MEK/ERK pathway. Insulin-like growth factor-1 enhanced F-actin assembly and this process was only PI3K mediated. Stimulation by IGF-1 of VEGF production was reduced by PD98059, indicating that only the MEK-ERK pathway is involved in IGF-1-stimulated VEGF production. In conclusion, IGF-1 mediates its multiple effects on MM cells through different signal transduction pathways. In the future, we can study the potential in vivo effects of IGF-1 inhibition on tumour growth and angiogenesis in MM.