LY2228820 Dimesylate, a Selective Inhibitor of p38 Mitogen-activated Protein Kinase, Reduces Angiogenic Endothelial Cord Formation in Vitro and in Vivo[S]

• Published in: The Journal of biological chemistry Vol. 288; no. 9; pp. 6743 - 6753
• Main Authors: Tate, Courtney M., Blosser, Wayne, Wyss, Lisa, Evans, Glenn, Xue, Qi, Pan, Yong, Stancato, Louis
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.03.2013; American Society for Biochemistry and Molecular Biology
• Subjects: Angiogenesis; Animals; Cancer Therapy; Cell Biology; Cytokines - metabolism; Endothelial Cell; Endothelial Cord Formation; Endothelium, Vascular - enzymology; Endothelium, Vascular - pathology; HSP27 Heat-Shock Proteins - genetics; HSP27 Heat-Shock Proteins - metabolism; Humans; Imidazoles - pharmacology; Intracellular Signaling Peptides and Proteins - genetics; Intracellular Signaling Peptides and Proteins - metabolism; MAP Kinases (MAPKs); Mice; Mice, Nude; Mitogen-Activated Protein Kinase 14 - antagonists & inhibitors; Mitogen-Activated Protein Kinase 14 - genetics; Mitogen-Activated Protein Kinase 14 - metabolism; Neoplasms - drug therapy; Neoplasms - enzymology; Neoplasms - genetics; Neoplasms - pathology; Neovascularization, Pathologic - enzymology; Neovascularization, Pathologic - genetics; Neovascularization, Pathologic - pathology; Protein Kinase Inhibitors - pharmacology; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - metabolism; Pyridines - pharmacology; Tumor Microenvironment - drug effects; Endothelial Cord Formation; Angiogenesis; Cancer Therapy; MAP Kinases (MAPKs); Endothelial Cell; Cell Biology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M112.425553

LY2228820 dimesylate is a highly selective small molecule inhibitor of p38α and p38β mitogen-activated protein kinases (MAPKs) that is currently under clinical investigation for human malignancies. p38 MAPK is implicated in a wide range of biological processes, in particular those that support tumorigenesis. One such process, angiogenesis, is required for tumor growth and metastasis, and many new cancer therapies are therefore directed against the tumor vasculature. Using an in vitro co-culture endothelial cord formation assay, a surrogate of angiogenesis, we investigated the role of p38 MAPK in growth factor- and tumor-driven angiogenesis using LY2228820 dimesylate treatment and by shRNA gene knockdown. p38 MAPK was activated in endothelial cells upon growth factor stimulation, with inhibition by LY2228820 dimesylate treatment causing a significant decrease in VEGF-, bFGF-, EGF-, and IL-6-induced endothelial cord formation and an even more dramatic decrease in tumor-driven cord formation. In addition to involvement in downstream cytokine signaling, p38 MAPK was important for VEGF, bFGF, EGF, IL-6, and other proangiogenic cytokine secretion in stromal and tumor cells. LY2228820 dimesylate results were substantiated using p38α MAPK-specific shRNA and shRNA against the downstream p38 MAPK effectors MAPKAPK-2 and HSP27. Using in vivo models of functional neoangiogenesis, LY2228820 dimesylate treatment reduced hemoglobin content in a plug assay and decreased VEGF-A-stimulated vascularization in a mouse ear model. Thus, p38α MAPK is implicated in tumor angiogenesis through direct tumoral effects and through reduction of proangiogenic cytokine secretion via the microenvironment.