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From the Laboratory of Tumor Biology and Genetics, Neurosurgery Department, University Hospital
(CHUV), 1011 Lausanne, Switzerland
Leukocyte infiltration and necrosis are two biological phenomena associated with the development of neovascularization during the malignant progression of human astrocytoma. Here, we
demonstrate expression of interleukin (IL)-8, a cytokine with chemotactic and angiogenic
properties, and of IL-8-binding receptors in astrocytoma. IL-8 expression is first observed in
low grade astrocytoma in perivascular tumor areas expressing inflammatory cytokines. In glioblastoma, it further localizes to oxygen-deprived cells surrounding necrosis. Hypoxic/anoxic
insults on glioblastoma cells in vitro using anaerobic chamber systems or within spheroids developing central necrosis induced an increase in IL-8 messenger RNA (mRNA) and protein
expression. mRNA for IL-8-binding chemokine receptors CXCR1, CXCR2, and the Duffy
antigen receptor for chemokines (DARC) were found in all astrocytoma grades by reverse
transcription/PCR analysis. In situ hybridization and immunohistochemistry localized DARC
expression on normal brain and tumor microvascular cells and CXCR1 and CXCR2 expression to infiltrating leukocytes. These results support a model where IL-8 expression is initiated
early in astrocytoma development through induction by inflammatory stimuli and later in tumor progression increases due to reduced microenvironmental oxygen pressure. Augmented
IL-8 would directly and/or indirectly promote angiogenesis by binding to DARC and by inducing leukocyte infiltration and activation by binding to CXCR1 and CXCR2.
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