title: Depletion of beta-arrestin-2 promotes tumor growth and angiogenesis in a murine model of lung cancer.
abstract: Arrestins are adaptor/scaffold proteins that complex with activated and phosphorylated G protein-coupled receptor to terminate G protein activation and signal transduction. These complexes also mediate downstream signaling, independently of G protein activation. We have previously shown that beta-arrestin-2 (betaarr2) depletion promotes CXCR2-mediated cellular signaling, including angiogenesis and excisional wound closure. This study was designed to investigate the role of betaarr2 in tumorigenesis using a murine model of lung cancer. To that end, heterotopic murine Lewis lung cancer and tail vein metastasis tumor model systems in betaarr2-deficient mice (betaarr2(-/-)) and control littermates (betaarr2(+/+)) were used. betaarr2(-/-) mice exhibited a significant increase in Lewis lung cancer tumor growth and metastasis relative to betaarr2(+/+) mice. This correlated with decreased number of tumor-infiltrating lymphocytes but with elevated levels of the ELR(+) chemokines (CXCL1/keratinocyte-derived chemokine and CXCL2/MIP-2), vascular endothelial growth factor, and microvessel density. NF-kappaB activity was also enhanced in betaarr2(-/-) mice, whereas hypoxia-inducible factor-1alpha expression was decreased. Inhibition of CXCR2 or NF-kappaB reduced tumor growth in both betaarr2(-/-) and betaarr2(+/+) mice. NF-kappaB inhibition also decreased ELR(+) chemokines and vascular endothelial growth factor expression. Altogether, the data suggest that betaarr2 modulates tumorigenesis by regulating inflammation and angiogenesis through activation of CXCR2 and NF-kappaB.
authors.affiliation: Julius L. Chambers Biomedical/Biotechnology Research Institute, Department of Biology, North Carolina Central University, Durham, NC 27707, USA.
authors.forename: Sandeep K
authors.initials: SK
authors.lastname: Raghuwanshi
authors.forename: Mohd W
authors.initials: MW
authors.lastname: Nasser
authors.forename: Xiaoxin
authors.initials: X
authors.lastname: Chen
authors.forename: Robert M
authors.initials: RM
authors.lastname: Strieter
authors.forename: Ricardo M
authors.initials: RM
authors.lastname: Richardson
mesh_terms: D000818:Animals; D019390:Arrestins / Q000172:deficiency / Q000276:immunology / Q000378:metabolism*; D019743:Chemokines, CXC / Q000276:immunology / Q000378:metabolism*; D004195:Disease Models, Animal; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D008175:Lung Neoplasms / Q000276:immunology / Q000378:metabolism* / Q000473:pathology*; D051379:Mice; D008817:Mice, Mutant Strains; D016328:NF-kappa B / Q000378:metabolism*; D009389:Neovascularization, Pathologic; D023063:Receptors, Interleukin-8B / Q000276:immunology / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins
chemical_list: C000605258:Arrb2 protein, mouse; D019390:Arrestins; D019743:Chemokines, CXC; C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D016328:NF-kappa B; D023063:Receptors, Interleukin-8B; D042461:Vascular Endothelial Growth Factor A; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins