The two carcinoma cell lines HeLa and HTM-29 show different behaviour in terms of interleukin-6 (IL-6) production. Analyses of secreted IL-6 by ELISA and of IL-6 mRNA by reverse transcription–PCR revealed that, whereas HeLa cells produced high levels of IL-6 in response to tumour necrosis factor-α (TNF-α) and IL-1β, the HTM-29 cell line failed to produce both IL-6 protein and mRNA. Nevertheless, the transcription factors nuclear factor-κB (NF-κB) and NF-IL6, the main factors involved in IL-6 gene transcriptional activation by cytokines, were activated in both cell lines after treatment with TNF-α or IL-1β. In order to verify that the lack of IL-6 expression in HTM-29 cells was not due to an endogenous IL-6 gene deficiency or to IL-6 mRNA instability, we carried out transient transfection assays with an IL-6 promoter–reporter construct. Strong activation of the IL-6 promoter by cytokines could be observed in HeLa cells, whereas no induction could be detected in cytokine-treated HTM-29 cells. These cytokines induced a very strong stimulation of NF-κB-mediated transcription in HeLa cells transfected with a κB luceriferase reporter construct, whereas no induction could be detected in cytokine-stimulated HTM-29 cells. Thus IL-6 promoter repression in HTM-29 cells probably results from a failure of cytokine-activated NF-κB to exert its transactivating activities. Western blotting experiments demonstrated that the lack of NF-κB-mediated transcription was not due to increased expression of IκB (inhibitor of NF-κB) proteins in HTM-29 cells. Co-transfection experiments with the κB Luc reporter construct and the CBP [CREB (cAMP response element binding protein) binding protein] expression vector showed that the impairment in NF-κB-dependent transcription did not result from a deficiency in the co-activator CBP. Interestingly, both NF-κB-mediated transcription and IL-6 promoter activation could be restored in HTM-29 cells by transfection with RelA. Furthermore, CBP could have a significant synergistic effect on exogenous RelA-mediated transcription. Since sequencing of the endogenous relA gene did not reveal any mutation, it is likely that repression of NF-κB-mediated transcription results from negative cross-talk between NF-κB and another nuclear factor specifically expressed or regulated by TNF-α in HTM-29 cells.
Skip Nav Destination
Follow us on Twitter @Biochem_Journal
Article navigation
August 2000
-
Cover Image
Cover Image
- PDF Icon PDF LinkFront Matter
- PDF Icon PDF LinkTable of Contents
Research Article|
July 25 2000
Regulation of interleukin-6 gene expression by pro-inflammatory cytokines in a colon cancer cell line Available to Purchase
Sylvie LEGRAND-POELS;
Sylvie LEGRAND-POELS
1Laboratory of Virology & Immunology, Institute of Pathology B23, University of Liège, B-4000 Liège, Belgium
Search for other works by this author on:
Sonia SCHOONBROODT;
Sonia SCHOONBROODT
1Laboratory of Virology & Immunology, Institute of Pathology B23, University of Liège, B-4000 Liège, Belgium
Search for other works by this author on:
Jacques PIETTE
Jacques PIETTE
1
1Laboratory of Virology & Immunology, Institute of Pathology B23, University of Liège, B-4000 Liège, Belgium
1To whom correspondence should be addressed (e-mail [email protected]).
Search for other works by this author on:
Publisher: Portland Press Ltd
Received:
October 25 1999
Revision Received:
April 18 2000
Accepted:
May 19 2000
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London © 2000
2000
Biochem J (2000) 349 (3): 765–773.
Article history
Received:
October 25 1999
Revision Received:
April 18 2000
Accepted:
May 19 2000
Citation
Sylvie LEGRAND-POELS, Sonia SCHOONBROODT, Jacques PIETTE; Regulation of interleukin-6 gene expression by pro-inflammatory cytokines in a colon cancer cell line. Biochem J 1 August 2000; 349 (3): 765–773. doi: https://doi.org/10.1042/bj3490765
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
Biochemical Society Member Sign in
Sign InSign in via your Institution
Sign in via your InstitutionGet Access To This Article
Follow us on Twitter @Biochem_Journal
Open Access for all
We offer compliant routes for all authors from 2025. With library support, there will be no author nor reader charges in 5 journals. Check here |
![]() View past webinars > |