Analysis of interleukin (IL)-8 expression in human astrocytomas: associations with IL-6, cyclooxygenase-2, vascular endothelial growth factor, and microvessel morphometry

Hum Immunol. 2009 Jun;70(6):391-7. doi: 10.1016/j.humimm.2009.03.011. Epub 2009 Mar 27.

Abstract

Malignant astrocytomas are highly vascular neoplasms with potent angiogenic activity. The present study aimed to investigate peripheral and local expression of interleukin (IL)-8 in astrocytomas with possible associations to IL-6, cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF) expression, and microvessel morphometry. IL-6- and IL-8-secreting peripheral blood monocytes (PBMCs) were evaluated in 17 glioblastoma (WHO grade IV), 5 anaplastic astrocytoma (WHO grade III), and 6 diffuse astrocytoma patients (WHO grade II), in parallel with 23 healthy controls using enzyme-linked immunosorbent spot (ELISPOT) assay. The IL-8 expression was assessed immunohistochemically in patients' tumor tissue sections and correlated with the expression of COX-2, VEGF, IL-6, and microvessel morphometry (assessed using CD34 antibody). Eighteen cases were also stained for CD31 and used as an additional vessel marker to validate our results regarding microvessel morphometry. IL-6 and IL-8 were highly secreted in the PBMCs of glioma patients compared with controls (p = 0.0001, p < 0.0001, respectively), with a positive correlation between IL-8 expression and secretion levels (p = 0.001). IL-8 immunoreactivity was detected in malignant cells or macrophages in perivascular areas and in pseudopalisading cells around necrosis and was positively correlated with histological grade (p = 0.0175) and tumor necrosis (p = 0.0793). IL-6 and IL-8 expression levels were positively correlated (p = 0.0036) and associated with COX-2 and VEGF expression (IL-6: p = 0.0133, p = 0.065; IL-8: p = 0.0139, p = 0.0101), but not with microvessel morphometry, by either CD31 or CD34. The coordinate expression and topographical relationship of IL-6, IL-8, COX-2, and VEGF in the same tumor areas (e.g., perinecrotic areas) attest to their intimate liaison in terms of cancer-induced angiogenesis, which is probably secondary to the induction of multiple interdependent molecular pathways. Moreover, our study seems to be the first attempt to link IL-8 expression by tumor cells with histological grade, implicating its potent role in gliomagenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Antigens, CD34 / immunology
  • Astrocytoma / blood supply
  • Astrocytoma / immunology*
  • Astrocytoma / pathology
  • Brain Neoplasms / blood supply
  • Brain Neoplasms / immunology*
  • Brain Neoplasms / pathology
  • Cyclooxygenase 2 / immunology*
  • Female
  • Humans
  • Interleukin-6 / immunology
  • Interleukin-8 / immunology
  • Leukocytes, Mononuclear / immunology
  • Male
  • Microvessels / immunology*
  • Microvessels / pathology
  • Middle Aged
  • Neovascularization, Pathologic / pathology
  • Vascular Endothelial Growth Factor A / immunology*
  • Young Adult

Substances

  • Antigens, CD34
  • Interleukin-6
  • Interleukin-8
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • Cyclooxygenase 2