IL (interleukin)-1alpha promotes nuclear factor-kappaB and AP-1-induced IL-8 expression, cell survival, and proliferation in head and neck squamous cell carcinomas.
Interleukin 1alpha (IL-1alpha) is an important regulatory cytokine, the release of which after an injury can induce activation of transcription factors nuclear factor (NF)kappaB and activator protein (AP-1), which promote expression of genes involved in cell survival, proliferation, and angiogenesis. IL-1alpha is expressed autonomously by head and neck squamous cell carcinomas (HNSCCs) and a variety of other cancers, raising the possibility that IL-1alpha may serve as an autocrine factor that stimulates the activation of prosurvival transcription factors and target genes in cancer. In this study, we examined the role of IL-1alpha in the activation of NFkappaB and AP-1, the expression of proangiogenic cytokine IL-8, and in the survival and proliferation of HNSCC cell lines. HNSCCs were found to secrete and respond to functional IL-1alpha, in that culture supernatant from a high IL-1alpha-secreting line, UM-SCC-11B, could induce secretion of cytokine IL-8 by a low IL-1alpha-secreting line, UM-SCC-9; and the induction of IL-8 secretion could be blocked by the anti-IL-1alpha-neutralizing antibody or the IL-1 receptor antagonist (IL-1RA). Furthermore, IL-1alpha could induce the expression of IL-8 through an autocrine mechanism, in that transfection of UM-SCC-9 cells with a plasmid encoding IL-1alpha resulted in the increased coexpression of IL-1alpha and IL-8; whereas transfection with a plasmid encoding IL-1RA lacking the secretory leader sequence led to the decreased coexpression of IL-1alpha and IL-8. IL-1alpha was found to induce coexpression of IL-8 through the activation of NFkappaB and AP-1, in that mutation of the NFkappaB site within the IL-8 promoter abolished autocrine- and recombinant IL-1alpha-induced IL-8 reporter gene activity, whereas mutation in AP-1 partially decreased IL-8 reporter gene activity in UM-SCC-9 cells. Intracellular expression of IL-1RA decreased NFkappaB reporter gene activity, indicating that endogenously expressed IL-1alpha contributes to constitutive NFkappaB activation in this HNSCC line. Expression of IL-1alpha affected survival of UM-SCC-9, inasmuch as transfection of cells with plasmid encoding IL-1alpha or IL-1RA led to the increased or decreased survival of cells cotransfected with a beta-galactosidase reporter gene, respectively. IL-1alpha was also found to promote the increased growth of UM-SCC-9 cells in vitro. We demonstrate that exogenous and endogenous IL-1alpha contributes to the transcriptional activation of NFkappaB and AP-1, to the expression of IL-8, and to cell survival and the growth of HNSCC in vitro.
Wolf
J S
JS
Tumor Biology Section, Head and Neck Surgery Branch, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, Maryland, 20892, USA.
Chen
Z
Z
Dong
G
G
Sunwoo
J B
JB
Bancroft
C C
CC
Capo
D E
DE
Yeh
N T
NT
Mukaida
N
N
Van Waes
C
C
D002294:Carcinoma, Squamous Cell / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival; D004396:Coloring Agents / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D017930:Genes, Reporter; D005822:Genetic Vectors; D006258:Head and Neck Neoplasms / Q000378:metabolism*; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism*; D016209:Interleukin-8 / Q000096:biosynthesis / Q000378:metabolism*; D009154:Mutation; D016328:NF-kappa B / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D013778:Tetrazolium Salts / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology; D013997:Time Factors; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection; D014407:Tumor Cells, Cultured
D004396:Coloring Agents; D007375:Interleukin-1; D016209:Interleukin-8; D016328:NF-kappa B; D011994:Recombinant Proteins; D013778:Tetrazolium Salts; D013844:Thiazoles; D018808:Transcription Factor AP-1; C022616:thiazolyl blue