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Cancer Res. 2007 Jan 15;67(2):585-92.

The inflammatory cytokine tumor necrosis factor-alpha generates an autocrine tumor-promoting network in epithelial ovarian cancer cells.

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  • 1Centre for Translational Oncology, Institute of Cancer and the Cancer Research-UK Clinical Centre and Bone and Joint Research Unit, William Harvey Research Institute, Barts and The London, Queen Mary's School of Medicine and Dentistry, United Kingdom.

Abstract

Constitutive expression of the inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) is characteristic of malignant ovarian surface epithelium. We investigated the hypothesis that this autocrine action of TNF-alpha generates and sustains a network of other mediators that promote peritoneal cancer growth and spread. When compared with two ovarian cancer cell lines that did not make TNF-alpha, constitutive production of TNF-alpha was associated with greater release of the chemokines CCL2 and CXCL12, the cytokines interleukin-6 (IL-6) and macrophage migration-inhibitory factor (MIF), and the angiogenic factor vascular endothelial growth factor (VEGF). TNF-alpha production was associated also with increased peritoneal dissemination when the ovarian cancer cells were xenografted. We next used RNA interference to generate stable knockdown of TNF-alpha in ovarian cancer cells. Production of CCL2, CXCL12, VEGF, IL-6, and MIF was decreased significantly in these cells compared with wild-type or mock-transfected cells, but in vitro growth rates were unaltered. Tumor growth and dissemination in vivo were significantly reduced when stable knockdown of TNF-alpha was achieved. Tumors derived from TNF-alpha knockdown cells were noninvasive and well circumscribed and showed high levels of apoptosis, even in the smallest deposits. This was reflected in reduced vascularization of TNF-alpha knockdown tumors. Furthermore, culture supernatants from such cells failed to stimulate endothelial cell growth in vitro. We conclude that autocrine production of TNF-alpha by ovarian cancer cells stimulates a constitutive network of other cytokines, angiogenic factors, and chemokines that may act in an autocrine/paracrine manner to promote colonization of the peritoneum and neovascularization of developing tumor deposits.

PMID:
17234767
[PubMed - indexed for MEDLINE]
PMCID:
PMC2679985
Free PMC Article

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