Involvement of interleukin-1b mediated nuclear factor kB signalling pathways to down-regulate prostate-specific antigen and cell proliferation in LNCaP prostate cancer cells Yosra Bouraoui*, Nawfel Ben Rais { , Zoran Culig { and Ridha Oueslati 1 * * Unit of Immuno-Microbio Environmental and Carcinogenesis, Faculty of Sciences of Bizerte, University of Carthage, 7021, Zarzouna, Bizerte, Tunisia { Department of Urology, Military Hospital (H.M.P.T), Tunis, Tunisia { Department of Urology, Innsbruck Medical University, Anichstrasse 35, A-6020 Innsbruck, Austria Abstract Involvement of NF-kB (nuclear factor kB) mediated by IL-1b (interleukin-1b) on cell proliferation and PSA (prostate-specific antigen) production of LNCaP prostate cell lines and the possible cross-talk with Akt (also known as protein kinase B) signalling pathway has been investigated. NF-kB and Akt were analysed by Western blotting from LNCaP cells treated by IL-1b before proliferation and PSA production were measured. IL-1b inhibited proliferation and decreased PSA production. The Akt pathway was not sensitive, whereas NF-kB phosphorylation occurred as a result of treatment. PSA production and proliferation of LNCaP cells were down-regulated by NF-kB mediated by IL-1b promoting anti-apoptotic signalling and co- suppressor factors of PSA expression. IL-1b through NF-kB activation provides a rationale for therapeutic approaches in the anticancer treatment of prostate. Keywords: interleukin-1b (IL-1b); nuclear factor kB (NF-kB); prostate-specific antigen (PSA); signalling pathways 1. Introduction Prostate cancer is the most frequently diagnosed cancer among men and the second leading cause of male cancer deaths (Jemal et al., 2010). PSA (prostate-specific antigen) is a 33 kDa serine protease belongs to the tissue kallikrein family and is pro- duced by the prostate gland (Balk et al., 2003), which is released at increased levels in blood early in the development of the prostate cancer and in parallel with disease progression. PSA expression is regulated by androgens through the AR (androgen receptor; Trapman and Cleutjens, 1997; Grossmann et al., 2001). In spite of initial sensitivity, prostate cancer cells became resistant to current therapies, but the mechanism responsible for the development of androgen-independent cancer remains unknown. However, accumulating evidence suggests that the androgen-independent phenotype arises when prostate cancer cells acquire a paracrine or autocrine growth mechanism through production of growth factors and cytokines (Nickerson et al., 2001; Taplin and Balk, 2004; Huang et al., 2006). At this state of disease, the PSA gene continues to be expressed (Heinlein and Chang, 2004). Several intracellular transduction pathways are involved in the regulation of PSA expression and production such as MAPK (mitogen-activated protein kinase), JAK (Janus kinase), STAT (signal transducer and activator of transcription), PKA (protein kinase A) and PI3K (phosphoinositide 3-kinase)/Akt (also known as protein kinase B) (Ueda et al., 2002; Jia et al., 2004). The PI3K/Akt pathway is a major survival system in human cancer relating to the development and progression of specific malignancies, such as prostate cancer (Paez and Seller, 2003; Edwards et al., 2003; Wu et al., 1998). The NF-kB (nuclear factor kB; p50/p65) pathway is affected by Akt (Romashkova and Makarov, 1999; Ozes et al., 1999). The NF-kB (p50/65) pathway plays a role in the control of the in- flammation, immune responses, proliferation, differentiation and apoptosis (Li and Verma, 2002; Chen et al., 2001; Li and Stark 2002; Caamano and Hunter, 2002) as well as cell development and progression of various human malignancies (Karin et al., 2002). The NF-kB signalling pathway is constitutively activated in human prostate cancer, and involved in the development and progression of prostate cancer (Sweeney et al., 2004; Jin et al., 2008). In addition, NF-kB activates a transcription-regulatory element of the PSA-encoding gene (Chen and Sawyers, 2002; Lee et al., 2003). IL-1b (interleukin-1b) is a classical inducer of phosphorylation and activation of NF-kB (p50/p65) signalling pathway and recent reports showed that Akt also regulates the NF-kB pathway induced by this cytokine (Sizemore et al.,1999; Madrid et al., 2001). IL-b stimulation triggers p65 phosphorylation at residue Ser 536 and TBK-1 {TANK [TRAF (tumour necrosis-factor-receptor- associated factor)-associated nuclear factor-kB activator]-binding kinase-1} activity with this NF-kB protein has been reported. Genistein, an inhibitor of protein kinase provokes inhibition of NF- kB activation mediated Akt signalling pathways in PC-3 prostate cells (Buss et al., 2004; Fujita et al., 2003; Li and Sarkar, 2002). IL- 1b is a potent multifunctional pro-inflammatory cytokine involved 1 To whom correspondence should be addressed (email oridha2003@yahoo.fr). Abbreviations: Akt, protein kinase B; AR, androgen receptor; FCS, fetal calf serum; IL-1b, interleukin-1b; MAPK, mitogen-activated protein kinase; NF-kB, nuclear factor kB; PI3K, phosphoinositide 3-kinase; PSA, prostate-specific antigen; STAT, signal transducer and activator of transcription; TNFa, tumour necrosis factor a. Cell Biol. Int. (2012) 36, 449–454 (Printed in Great Britain) Research Article E The Author(s) Journal compilation E 2012 International Federation for Cell Biology Volume 36 (5) N pages 449–454 N doi:10.1042/CBI20100922 N www.cellbiolint.org 449