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. 2004 Wiley-Liss, Inc.
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 NFkappaBp65 and C/EBP-beta, and blockade of NFkappaB with IkappaBalpha or CAPE were performed to demonstrate the cooperation between NFkappaBp65 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 NFkappaBp65 and C/EBP-beta did not require a functional IL6-NFkappaB binding site. CONCLUSIONS: These data support a unique role for NFkappaBp65 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. 2004 Wiley-Liss, Inc.
Authors: Erika H Noss; Hung N Nguyen; Sook Kyung Chang; Gerald F M Watts; Michael B Brenner Journal: Proc Natl Acad Sci U S A Date: 2015-11-17 Impact factor: 11.205
Authors: Sizhi Paul Gao; Kevin G Mark; Kenneth Leslie; William Pao; Noriko Motoi; William L Gerald; William D Travis; William Bornmann; Darren Veach; Bayard Clarkson; Jacqueline F Bromberg Journal: J Clin Invest Date: 2007-12 Impact factor: 14.808
Authors: Brett D Hollingshead; Timothy V Beischlag; Brett C Dinatale; Preeti Ramadoss; Gary H Perdew Journal: Cancer Res Date: 2008-05-15 Impact factor: 12.701
Authors: Brian T Kawasaki; Elaine M Hurt; Madhuri Kalathur; Maria Ana Duhagon; John A Milner; Young S Kim; William L Farrar Journal: Prostate Date: 2009-06-01 Impact factor: 4.104