Interleukin-3 Stimulation of mcl-1 Gene Transcription Involves Activation of the PU.1 Transcription Factor through a p38 Mitogen-Activated Protein Kinase-Dependent Pathway

Institute of Molecular Biology, Academia Sinica, 128 Yen-Jiou Yuan Road, Section 2, Nankang, Taipei 11529, Taiwan, Republic of China.
Molecular and Cellular Biology (Impact Factor: 4.78). 04/2003; 23(6):1896-909. DOI: 10.1128/MCB.23.6.1896-1909.2003
Source: PubMed


We have previously demonstrated that the antiapoptotic gene mcl-1 is activated by interleukin-3 (IL-3) in Ba/F3 pro-B cells through two promoter elements designated the CRE-2 and SIE motifs. While the CRE-2-binding complex contains the CREB protein and is activated by IL-3 through the phosphatidylinositol 3-kinase/Akt-dependent pathway, the identity and cytokine activation pathway of the SIE-binding complex remains unclear. In this report, we demonstrated that PU.1 is one component of the SIE-binding complex. A chromatin immunoprecipitation assay further confirmed that PU.1 binds to the mcl-1 promoter region containing the SIE motif in vivo. While IL-3 stimulation does not significantly alter the SIE-binding activity of PU.1, it markedly increases PU.1's transactivation activity. The latter effect coincides with the increased phosphorylation of PU.1 following IL-3 activation of a p38 mitogen-activated protein kinase (p38(MAPK))-dependent pathway. A serine-to-alanine substitution at position 142 significantly weakens PU.1's ability to be phosphorylated by the p38(MAPK) immunocomplex. Furthermore, this S142A mutant is impaired in the ability to be further stimulated by IL-3 to transactivate the mcl-1 reporter through the SIE motif. Taken together, our results demonstrate that IL-3 stimulation of mcl-1 gene transcription through the SIE motif involves phosphorylation of PU.1 at serine 142 by a p38(MAPK)-dependent pathway.

Download full-text


Available from: Ju Ming Wang, Oct 07, 2015
5 Reads
  • Source
    • "Analysis of human Mcl-1 gene 5′-flanking promoter regions for potential transcription factor binding sites revealed consensus sequences including STAT, SRE, Ets, Sp1, CRE-BP [9]. Multiple intracellular signaling pathways and transcription factors have been confirmed to influence Mcl-1 expression, including PI3K/Akt [10], Stat3 [11,12], CREB [10], Ets family members Elk-1 [13] and PU.1 [14]. In addition, putative binding sites for NF-κB were identified in the Mcl-1 promoter region [9]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Esophageal squamous cell carcinoma (ESCC) is one of the most lethal malignancies with a 5-year survival rate less than 15%. Understanding of the molecular mechanisms involved in the pathogenesis of ESCC becomes critical to develop more effective treatments. Mcl-1 expression was measured by reverse transcription (RT)-PCR and Western blotting. Human Mcl-1 promoter activity was evaluated by reporter gene assay. The interactions between DNA and transcription factors were confirmed by electrophoretic mobility shift assay (EMSA) in vitro and by chromatin immunoprecipitation (ChIP) assay in cells. Four human ESCC cell lines, TE-1, Eca109, KYSE150 and KYSE510, are revealed increased levels of Mcl-1 mRNA and protein compare with HaCaT, an immortal non-tumorigenic cell line. Results of reporter gene assays demonstrate that human Mcl-1 promoter activity is decreased by mutation of kappaB binding site, specific NF-kappaB inhibitor Bay11-7082 or dominant inhibitory molecule DNMIkappaBalpha in TE-1 and KYSE150 cell lines. Mcl-1 protein level is also attenuated by Bay11-7082 treatment or co-transfection of DNMIkappaBalpha in TE-1 and KYSE150 cells. EMSA results indicate that NF-kappaB subunits p50 and p65 bind to human Mcl-1-kappaB probe in vitro. ChIP assay further confirm p50 and p65 directly bind to human Mcl-1 promoter in intact cells, by which regulates Mcl-1 expression and contributes to the viability of TE-1 cells. Our data provided evidence that one of the mechanisms of Mcl-1 expression in human ESCC is regulated by the activation of NF-kappaB signaling. The newly identified mechanism might provide a scientific basis for developing effective approaches to treatment human ESCC.
    BMC Cancer 02/2014; 14(1):98. DOI:10.1186/1471-2407-14-98 · 3.36 Impact Factor
  • Source
    • "TNFSF10 or TNFSF10 agonists bind to TNFRSF10A or TNFRSF10B and form deathinducing signalling complex (DISC), which is a multi-protein complex consisting of an adaptor molecule, FADD and the initiator of extrinsic pathway caspase-8. (Wang and El-Deiry, 2003; Johnstone et al., 2008) Activated caspase-8 is capable of both initiating an extrinsic apoptotic pathway in type I cells (through activation of caspase-3, -6, and -7) and triggering the intrinsic pathway in type II cells (through activation of Bid) (Li et al., 1998; Johnstone et al., 2008). CS-1008 is a novel TNFRSF10B agonist that exerts TNFSF10-like activity. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Background and purpose: Previously, we have shown that sorafenib sensitizes hepatocellular carcinoma (HCC) to apoptosis induced by TNF-related apoptosis-inducing ligand (TNFSF10; TRAIL). Here, we report that sorafenib and SC-49 sensitize HCC cells to CS-1008, a novel anti-human death receptor 5 (TNFRSF10B) antibody. Experimental approach: HCC cell lines (PLC5, Huh-7, and Hep3B) were treated with CS-1008 and/or sorafenib and analysed in terms of apoptosis and signal transductions. Key results: SC-49 is a sorafenib derivative, which is devoid of kinase inhibitory activity. Both sorafenib and SC-49 down-regulated the phosphorylation of STAT3 at Tyr(705) and subsequently reduced the levels of STAT3-regulated proteins, Mcl-1, survivin and cylcin D1, in CS-1008-treated HCC cells. Knockdown of STAT3 by RNA interference overcame apoptotic resistance to CS-1008 in HCC cells, and ectopic expression of STAT3 in HCC cells abolished the sensitizing effects of sorafenib and SC-49 on CS-1008-induced apoptosis, indicating that inhibition of STAT3 mediates the enhancing effects of these compounds when combined with CS-1008. Importantly, inhibition of SHP-1 by adding a specific SHP-1 inhibitor reduced the effects of SC-49 and CS-1008 on p-STAT3 and apoptosis, whereas co-treatment of CS-1008 with SC-49 increased the activity of SHP-1. These data indicate that the combined effects of CS-1008 and SC-49 on HCC are mediated by SHP-1. Moreover, the combination of CS-1008 and SC-49 inhibited HCC xenograft tumour growth in vivo. Conclusions and implications: Sorafenib and its derivative SC-49 sensitize HCC cells to the antitumour effects of CS-1008 through SHP-1-dependent inactivation of STAT3.
    British Journal of Pharmacology 09/2012; 168(3). DOI:10.1111/j.1476-5381.2012.02212.x · 4.84 Impact Factor
  • Source
    • "In this way, glucocorticoids are able to regulate apoptosis at the mitochondrial level (Fig. 1). In addition, many studies have confirmed the importance of PI3K and p38 MAPK in neutrophils and other cell types that respond to pro-survival agents by enhancing Mcl-1 [34, 35, 86]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Neutrophil-dominated inflammation plays an important role in many airway diseases including asthma, chronic obstructive pulmonary disease (COPD), bronchiolitis and cystic fibrosis. In cases of asthma where neutrophil-dominated inflammation is a major contributing factor to the disease, treatment with corticosteroids can be problematic as corticosteroids have been shown to promote neutrophil survival which, in turn, accentuates neutrophilic inflammation. In light of such cases, novel targeted medications must be developed that could control neutrophilic inflammation while still maintaining their antibacterial/anti-fungal properties, thus allowing individuals to maintain effective innate immune responses to invading pathogens. The aim of this review is to describe the molecular mechanisms of neutrophil apoptosis and how these pathways are modulated by glucocorticoids. These new findings are of potential clinical value and provide further insight into treatment of neutrophilic inflammation in lung disease.
    Current drug targets 04/2011; 12(4):556-62. DOI:10.2174/138945011794751555 · 3.02 Impact Factor
Show more