title: Regulation of interleukin 8 expression in human malignant melanoma cells.
abstract: Here, we report the molecular regulation of interleukin (IL)-8 expression in human melanoma cells. The inflammatory cytokines IL-1beta and tumor necrosis factor-alpha (TNF-alpha) up-regulated IL-8 expression, in a time- and concentration-dependent manner, in three metastatic melanoma variants, SBC-2 (nonmetastatic), A375P (low metastatic), and A375SM (high metastatic), by increased transcription of the IL-8 gene, leading to increased levels of IL-8 mRNA and protein production. Furthermore, we report that IFN-alpha and IFN-beta did not inhibit steady-state IL-8 production. However, IFN-alpha and IFN-beta inhibited IL-1beta or TNF-alpha-mediated up-regulation of IL-8 mRNA. In addition, IFN-beta demonstrated a more potent inhibitory effect at a lower concentration than did IFN-alpha. Both pretreatment and simultaneous treatment of melanoma cells with IFN-alpha or IFN-beta inhibited the IL-1beta and TNF-alpha up-regulation of IL-8 mRNA levels. This inhibition was at the transcriptional levels and was unaffected by a protein synthesis inhibitor, suggesting that this did not require de novo protein synthesis. Further, modulation of IL-8 levels by IL-1beta, alone or in combination with IFN-beta, affected the proliferation of melanoma cells. In summary, our data suggest that the up-regulation of IL-8 expression in melanoma cells is regulated at the transcriptional level and is rapidly and specifically inhibited by IFN-alpha or IFN-beta, independent of de novo protein synthesis, perhaps due to a transient modification of a preexisting factor(s).
authors.affiliation: Department of Pathology and Microbiology, The University of Nebraska Medical Center, Omaha 68198-5660, USA. rsingh@mail.unmc.edu
authors.forename: R K
authors.initials: RK
authors.lastname: Singh
authors.forename: M L
authors.initials: ML
authors.lastname: Varney
mesh_terms: D000818:Animals; D002455:Cell Division / Q000502:physiology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics; D006801:Humans; D016899:Interferon-beta / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000378:metabolism; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology / Q000556:secondary; D051379:Mice; D008819:Mice, Nude; D012333:RNA, Messenger / Q000378:metabolism; D013268:Stimulation, Chemical; D014158:Transcription, Genetic / Q000187:drug effects; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D015854:Up-Regulation
chemical_list: D007375:Interleukin-1; D016209:Interleukin-8; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D016899:Interferon-beta; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases