title: Expression and regulation of tumor necrosis factor alpha in normal and malignant ovarian epithelium.
abstract: Epidemiologic studies implicate inflammatory stimuli in the development of ovarian cancer. The proinflammatory cytokine tumor necrosis factor alpha (TNF-alpha) and both its receptors (TNFRI and TNFRII) are expressed in biopsies of this malignancy. Here, we tested the hypothesis that TNF-alpha is a regulator of the proinflammatory microenvironment of ovarian cancer. A cancer profiling array showed higher expression of TNF-alpha in ovarian tumors compared with normal ovarian tissue, and cultured ovarian cancer cells expressed up to 1,000 times more TNF-alpha mRNA than cultured normal ovarian surface epithelial cells; TNF-alpha protein was only detected in the supernatant of tumor cell cultures. Treatment with TNF-alpha induced TNF-alpha mRNA via TNFRI in both malignant and normal cells with evidence for enhanced TNF-alpha mRNA stability in tumor cells. TNF-alpha induced TNF-alpha protein in an autocrine fashion in tumor but not in normal ovarian surface epithelial cells. The TNF-alpha neutralizing antibody infliximab reduced the constitutive levels of TNF-alpha mRNA in tumor cell lines capable of autocrine TNF-alpha production. Apart from TNF-alpha mRNA expression, several other proinflammatory cytokines were constitutively expressed in malignant and normal ovarian surface epithelial cells, including interleukin (IL)-1alpha, IL-6, CCL2, CXCL8, and M-CSF. TNF-alpha treatment further induced these cytokines with de novo transcription of IL-6 mRNA contrasting with the increased stability of CCL2 mRNA. RNA interference directed against TNF-alpha was highly effective in abolishing constitutive IL-6 production by ovarian tumor cells. In summary, we show that TNF-alpha is differentially regulated in ovarian cancer cells compared with untransformed cells and modulates production of several cytokines that may promote ovarian tumorigenesis. Infliximab treatment may have a role in suppressing the TNF-alpha-driven inflammatory response associated with ovarian cancer.
authors.affiliation: Cancer Research UK, Translational Oncology Laboratory, Barts and The London, Queen Mary's School of Medicine and Dentistry, John Vane Science Centre, Charterhouse Square, London EC1M 6BQ, United Kingdom.
authors.forename: Peter W
authors.initials: PW
authors.lastname: Szlosarek
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Grimshaw
authors.forename: Hagen
authors.initials: H
authors.lastname: Kulbe
authors.forename: Julia L
authors.initials: JL
authors.lastname: Wilson
authors.forename: George D
authors.initials: GD
authors.lastname: Wilbanks
authors.forename: Frances
authors.initials: F
authors.lastname: Burke
authors.forename: Frances R
authors.initials: FR
authors.lastname: Balkwill
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology; D045744:Cell Line, Tumor; D018932:Chemokine CCL2 / Q000378:metabolism; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D005260:Female; D006801:Humans; D000069285:Infliximab; D015850:Interleukin-6 / Q000378:metabolism; D010051:Ovarian Neoplasms / Q000235:genetics / Q000378:metabolism*; D010053:Ovary / Q000187:drug effects / Q000378:metabolism*; D034622:RNA Interference; D020871:RNA Stability; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; C111835:CCL2 protein, human; D018932:Chemokine CCL2; D016207:Cytokines; D015850:Interleukin-6; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D000069285:Infliximab