BACKGROUND: The androgen receptor (AR) nuclear transcription factor is a therapeutic target for prostate cancer (PCa). Unfortunately, patients can develop resistance to AR-targeted therapies and progress to lethal disease, underscoring the importance of understanding the molecular mechanisms that underlie treatment resistance. Inflammation is implicated in PCa initiation and progression and we have previously reported that the inflammatory cytokine, interleukin-1 (IL-1), represses AR messenger RNA (mRNA) levels and activity in AR-positive (AR+ ) PCa cell lines concomitant with the upregulation of prosurvival biomolecules. Thus, we contend that IL-1 can select for AR-independent, treatment-resistant PCa cells. METHODS: To begin to explore how IL-1 signaling leads to the repression of AR mRNA levels, we performed comprehensive pathway analysis on our RNA sequencing data from IL-1-treated LNCaP PCa cells. Our pathway analysis predicted nuclear factor kappa B (NF-κB) p65 subunit (RELA), a canonical IL-1 signal transducer, to be significantly active and potentially regulate many genes, including AR. We used small interfering RNA (siRNA) to silence the NF-κB family of transcription factor subunits, RELA, RELB, c-REL, NFKB1, or NFKB2, in IL-1-treated LNCaP, C4-2, and C4-2B PCa cell lines. C4-2 and C4-2B cell lines are castration-resistant LNCaP sublines and represent progression toward metastatic PCa disease, and we have previously shown that IL-1 represses AR mRNA levels in C4-2 and C4-2B cells. RESULTS: siRNA revealed that RELA alone is sufficient to mediate IL-1 repression of AR mRNA and AR activity. Intriguingly, while LNCaP cells are more sensitive to IL-1-mediated repression of AR than C4-2 and C4-2B cells, RELA siRNA led to a more striking derepression of AR mRNA levels and AR activity in C4-2 and C4-2B cells than in LNCaP cells. CONCLUSIONS: These data indicate that there are RELA-independent mechanisms that regulate IL-1-mediated AR repression in LNCaP cells and suggest that the switch to RELA-dependent IL-1 repression of AR in C4-2 and C4-2B cells reflects changes in epigenetic and transcriptional programs that evolve during PCa disease progression.
BACKGROUND: The androgen receptor (AR) nuclear transcription factor is a therapeutic target for prostate cancer (PCa). Unfortunately, patients can develop resistance to AR-targeted therapies and progress to lethal disease, underscoring the importance of understanding the molecular mechanisms that underlie treatment resistance. Inflammation is implicated in PCa initiation and progression and we have previously reported that the inflammatory cytokine, interleukin-1 (IL-1), represses AR messenger RNA (mRNA) levels and activity in AR-positive (AR+ ) PCa cell lines concomitant with the upregulation of prosurvival biomolecules. Thus, we contend that IL-1 can select for AR-independent, treatment-resistant PCa cells. METHODS: To begin to explore how IL-1 signaling leads to the repression of AR mRNA levels, we performed comprehensive pathway analysis on our RNA sequencing data from IL-1-treated LNCaP PCa cells. Our pathway analysis predicted nuclear factor kappa B (NF-κB) p65 subunit (RELA), a canonical IL-1 signal transducer, to be significantly active and potentially regulate many genes, including AR. We used small interfering RNA (siRNA) to silence the NF-κB family of transcription factor subunits, RELA, RELB, c-REL, NFKB1, or NFKB2, in IL-1-treated LNCaP, C4-2, and C4-2BPCa cell lines. C4-2 and C4-2B cell lines are castration-resistant LNCaP sublines and represent progression toward metastatic PCa disease, and we have previously shown that IL-1 represses AR mRNA levels in C4-2 and C4-2B cells. RESULTS: siRNA revealed that RELA alone is sufficient to mediate IL-1 repression of AR mRNA and AR activity. Intriguingly, while LNCaP cells are more sensitive to IL-1-mediated repression of AR than C4-2 and C4-2B cells, RELA siRNA led to a more striking derepression of AR mRNA levels and AR activity in C4-2 and C4-2B cells than in LNCaP cells. CONCLUSIONS: These data indicate that there are RELA-independent mechanisms that regulate IL-1-mediated AR repression in LNCaP cells and suggest that the switch to RELA-dependent IL-1 repression of AR in C4-2 and C4-2B cells reflects changes in epigenetic and transcriptional programs that evolve during PCa disease progression.
Authors: Boyu Zhang; Oh-Joon Kwon; Gervaise Henry; Alicia Malewska; Xing Wei; Li Zhang; William Brinkley; Yiqun Zhang; Patricia D Castro; Mark Titus; Rui Chen; Mohammad Sayeeduddin; Ganesh V Raj; Ryan Mauck; Claus Roehrborn; Chad J Creighton; Douglas W Strand; Michael M Ittmann; Li Xin Journal: Mol Cell Date: 2016-09-01 Impact factor: 17.970
Authors: Diping Wang; R Bruce Montgomery; Lucy J Schmidt; Elahe A Mostaghel; Haojie Huang; Peter S Nelson; Donald J Tindall Journal: Cancer Res Date: 2009-12-15 Impact factor: 12.701
Authors: Ren Jie Jin; Yongsoo Lho; Linda Connelly; Yongqing Wang; Xiuping Yu; Leshana Saint Jean; Thomas C Case; Katharine Ellwood-Yen; Charles L Sawyers; Neil A Bhowmick; Timothy S Blackwell; Fiona E Yull; Robert J Matusik Journal: Cancer Res Date: 2008-08-15 Impact factor: 12.701
Authors: Ying-Chun Shen; Ali Ghasemzadeh; Christina M Kochel; Thomas R Nirschl; Brian J Francica; Zoila A Lopez-Bujanda; Maria A Carrera Haro; Ada Tam; Robert A Anders; Mark J Selby; Alan J Korman; Charles G Drake Journal: Prostate Cancer Prostatic Dis Date: 2017-12-04 Impact factor: 5.554
Authors: Daniel Compagno; Carole Merle; Aurélie Morin; Cristèle Gilbert; Jacques R R Mathieu; Aline Bozec; Claire Mauduit; Mohammed Benahmed; Florence Cabon Journal: PLoS One Date: 2007-10-10 Impact factor: 3.240
Authors: Z Culig; A Hobisch; M Herold; A Hittmair; M Thurnher; I E Eder; M V Cronauer; C Rieser; R Ramoner; G Bartsch; H Klocker; G Konwalinka Journal: Br J Cancer Date: 1998-10 Impact factor: 7.640
Authors: Haley C Dahl; Mohammed Kanchwala; Shayna E Thomas-Jardin; Amrit Sandhu; Preethi Kanumuri; Afshan F Nawas; Chao Xing; Chenchu Lin; Daniel E Frigo; Nikki A Delk Journal: PLoS One Date: 2020-12-16 Impact factor: 3.240