Co-operative functions between nuclear factors NFkappaB and CCAT/enhancer-binding protein-beta (C/EBP-beta) regulate the IL-6 promoter in autocrine human prostate cancer cells

Prostate. 2004 Dec 1;61(4):354-70. doi: 10.1002/pros.20113.


Background: IL-6 is a growth and survival factor for prostate cancer cells through autocrine pathways. Here, we have systematically examined the transcriptional regulation mechanisms of IL-6 in autocrine prostate cancer cells.

Methods: RT-PCR and immunohistochemical staining were used to determine IL-6 production in the cells. Serial mutant IL-6 promoter luciferase reporters were generated and their transcriptional activities were examined. The transcription factors involved in IL-6 regulation were identified with super-shift EMSA. Overexpression of NFkappaB p65 and C/EBP-beta, and blockade of NFkappaB with IkappaBalpha or CAPE were performed to demonstrate the cooperation between NFkappaB p65 and C/EBP-beta in activation of IL-6.

Results: Transcription factor regulatory sites IL6-NFkappaB, IL6-C/EBP, IL6-CREB, and IL6-AP1, are responsive to constitutively activated IL-6 production in autocrine prostate cancer cell lines. Among these sites, IL6-AP1 and IL6-C/EBP appear most important, while IL6-NFkappaB shows the least effect for IL-6 promoter activity as determined by mutant IL-6 promoter luciferase reporter assay. Nevertheless, nuclear factor NFkappaB is activated and required. Such activation is minimally dependent upon the IL6-NFkappaB site, occurring through cooperation with other transcription factors that bind the IL-6 promoter. Cooperation between NFkappaB p65 and C/EBP-beta did not require a functional IL6-NFkappaB binding site.

Conclusions: These data support a unique role for NFkappaB p65 as the primary trigger in autocrine production of IL-6 in prostate cancer cells. Furthermore, we describe a novel transcriptional activation mechanism for NFkappaB that is independent of its regulatory binding site, occurring through cooperation with other transcription factors that facilitate the neighboring regulatory site.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Sequence
  • Binding Sites
  • Blotting, Western
  • CCAAT-Enhancer-Binding Protein-beta / genetics
  • CCAAT-Enhancer-Binding Protein-beta / physiology*
  • Caffeic Acids / pharmacology
  • DNA / chemistry
  • DNA / metabolism
  • Gene Expression Regulation / drug effects
  • Humans
  • I-kappa B Proteins / pharmacology
  • Immunohistochemistry
  • Interleukin-6 / biosynthesis
  • Interleukin-6 / genetics*
  • Male
  • Molecular Sequence Data
  • NF-KappaB Inhibitor alpha
  • NF-kappa B / antagonists & inhibitors
  • NF-kappa B / genetics
  • NF-kappa B / physiology*
  • Phenylethyl Alcohol / analogs & derivatives*
  • Phenylethyl Alcohol / pharmacology
  • Promoter Regions, Genetic / genetics*
  • Prostatic Neoplasms / genetics
  • Prostatic Neoplasms / metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transcription Factors
  • Transcription, Genetic / drug effects
  • Transfection
  • Tumor Cells, Cultured


  • CCAAT-Enhancer-Binding Protein-beta
  • Caffeic Acids
  • I-kappa B Proteins
  • Interleukin-6
  • NF-kappa B
  • NFKBIA protein, human
  • Transcription Factors
  • NF-KappaB Inhibitor alpha
  • DNA
  • caffeic acid phenethyl ester
  • Phenylethyl Alcohol