BET Inhibitor JQ1 Blocks Inflammation and Bone Destruction.

BET proteins are a group of epigenetic regulators controlling transcription through reading acetylated histone tails and recruiting transcription complexes. They are considered as potential therapeutic targets in many distinct diseases. A novel synthetic bromodomain and extraterminal domain (BET) inhibitor, JQ1, was proved to suppress oncogene transcription and inflammatory responses. The present study was aimed to investigate the effects of JQ1 on inflammatory response and bone destruction in experimental periodontitis. We found that JQ1 significantly suppressed lipopolysaccharide (LPS)-stimulated inflammatory cytokine transcription, including interleukin (IL)-1ß, IL-6, and tumor necrosis factor alpha (TNF-α), as well as receptor activator of nuclear factor kappa-B ligand (RANKL)-induced osteoclast markers, such as c-Fos, nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1), tartrate-resistant acid phosphatase (TRAP) and cathepsin K in vitro. JQ1 also inhibited toll-like receptors 2/4 (TLR2/4) expression and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) phosphorylation and nuclear translocation. Chromatin immunoprecipitation and quantitative polymerase chain reaction (ChIP-qPCR) revealed that JQ1 neutralized BRD4 enrichment at several gene promoter regions, including NF-κB, TNF-α, c-Fos, and NFATc1. In a murine periodontitis model, systemic administration of JQ1 significantly inhibited inflammatory cytokine expression in diseased gingival tissues. Alveolar bone loss was alleviated in JQ1-treated mice because of reduced osteoclasts in periodontal tissues. These unprecedented results suggest the BET inhibitor JQ1 as a prospective new approach for treating periodontitis.

Deciphering the luteal transcriptome: potential mechanisms mediating stage-specific luteolytic response of the corpus luteum to prostaglandin F2α.

The objective of this study was to identify prostaglandin F(2α) (PG)-induced changes in the transcriptome of bovine corpora lutea (CL) that are specific to mature, PG-responsive (day 11) CL vs. developing (day 4) CL, which do not undergo luteolysis in response to PG administration. CL were collected at 0, 4, and 24 h after PG injection on days 4 and 11 of the estrous cycle (n = 5 per day and time point), and microarray analysis was performed with GeneChip Bovine Genome Arrays. Data normalization was performed with affy package and significance testing with maanova from Bioconductor. Significance (relative to 0 h time point) was declared at fold change >2.0 or <0.5 and false discovery rate of <5%. At 4 and 24 h after PG, 221 (day 4) and 661 (day 11) and 248 (day 4) and 1,421 (day 11) regulated genes, respectively, were identified. The accentuated gene expression response in day 11 CL was accompanied by specific enrichment of PG-regulated genes in distinctive gene ontology categories (immune related and other), particularly at 24 h after injection. Specificity in putative transcription factor binding sites was observed among PG-regulated genes on day 11 vs. day 4, including a potential association of ETS transcription factors with acute PG-induced gene expression specific to day 11 CL. Temporal and PG-induced regulation of abundance of mRNA for ETS transcription factor family members linked to the stage-specific response to PG was not observed. Increased abundance of protein and/or mRNA for six PG-regulated putative ETS-responsive genes was noted in day 11 but not day 4 CL. Results reveal insight into stage-specific gene expression in bovine CL in response to PG and potential transcriptional mediators of luteolysis.

Cardiac glycosides decrease prostate specific antigen expression by down-regulation of prostate derived Ets factor.

PURPOSE: While cardiac glycosides are the mainstay of congestive heart failure treatment, early studies showed that pharmacological doses of cardiac glycosides inhibited prostate cancer cell line proliferation. We evaluated the mechanisms of cardiac glycosides, including digoxin, digitoxin and ouabain (Sigma®), on prostate specific antigen gene expression in vitro. MATERIALS AND METHODS: We cultured LNCaP cells (ATCC®) and used them to determine the effect of cardiac glycosides on prostate derived Ets factor and prostate specific antigen expression. We determined prostate derived Ets factor and prostate specific antigen expression by reverse transcription-polymerase chain reaction, immunoblot, transient gene expression assay or enzyme-linked immunosorbent assay. RESULTS: Noncytotoxic doses (100 nM) of cardiac glycosides for 24 hours inhibited prostate specific antigen secretion by LNCaP cells. Reverse transcriptase-polymerase chain reaction and immunoblot revealed that cardiac glycosides significantly down-regulated prostate specific antigen and prostate derived Ets factor expression. Transient gene expression assays showed that prostate derived Ets factor over expression enhanced prostate specific antigen promoter activity. However, prostate specific antigen and prostate derived Ets factor gene promoter activity was attenuated when LNCaP cells were treated with 100 nM cardiac glycosides. When LNCaP cells were treated with 25 nM digitoxin or digoxin for 60 hours, prostate specific antigen secretion decreased by 30%. CONCLUSIONS: Results suggest that cardiac glycoside inhibition of prostate specific antigen gene expression may be caused by the down-regulation of prostate derived Ets factor gene expression. When cells were chronically treated with digoxin or digitoxin at concentrations close to or at therapeutic plasma levels, prostate specific antigen secretion decreased. This phenomenon merits further study to determine whether it occurs in men on cardiac glycoside therapy.

Curcumin blocks the activation of androgen and interlukin-6 on prostate-specific antigen expression in human prostatic carcinoma cells.

Curcumin, a naturally occurring compound, exhibits anticancer chemopreventive effects. We evaluated the effects and mechanisms of curcumin on the gene expression of prostate-specific antigen (PSA) in human androgen-sensitive prostatic carcinoma cells. LNCaP cells were used to determine the effect of curcumin on PSA expression. Quantitative PSA expression was assessed by reverse transcription polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and immunoblot assay. The modulation of androgen, interlukin-6 (IL-6), and prostate-derived Ets factor (PDEF) on the PSA gene was identified by transient gene expression assay with the use of a PSA reporter vector. The effect of curcumin on the activity of androgen receptors was evaluated by electrophoretic mobility shift assay (EMSA). Immunoblot assays, RT-PCR, and ELISA indicated that curcumin treatments blocked the stimulation of methyltrienolone (R1881) and IL-6 on PSA gene expression in LNCaP cells. The effects of curcumin appear to be mediated via the androgen response element of PSA gene. Results from immunoblot assay and EMSA revealed the modulation of curcumin on the expression of androgen receptor and androgen receptor binding activity on androgen response element of PSA gene. Although overexpression of PDEF dramatically enhanced PSA gene expression, the results of immunoblot assays and transient reporter assays indicated that curcumin treatments did not affect the gene expression of PDEF. Curcumin inhibits R1881- and IL-6-mediated PSA gene expression in LNCaP cells through down-regulation of the expression and activity of androgen receptors.

Prostate-derived Ets transcription factor as a favorable prognostic marker in ovarian cancer patients.

We have previously shown that ovarian tumors express prostate-derived Ets transcription factor (PDEF). However, the precise role of PDEF in the prognosis of ovarian cancer is unknown. In our study, we report for the first time that expression of PDEF in tumor lesions of patients with ovarian cancer is associated with favorable prognosis. Evaluation of samples from 40 patients with ovarian cancer showed that early stage (IA) and borderline (IIB, III) ovarian tumors expressed higher levels of PDEF mRNA and protein and lower levels of survivin compared to late stage ovarian tumors (IIIC and IV, p < 0.05). Normal ovarian tissues expressed the highest levels of PDEF mRNA and protein when compared to tumor tissues (p < 0.05). A Log-Rank test showed that overall survival of patients with PDEF-positive and survivin-negative ovarian tumors was significantly longer than those with PDEF-negative and survivin-positive tumors (p < 0.01). Forced expression of PDEF in PDEF-negative ovarian tumor cells inhibited tumor cell growth, induced apoptosis, downregulated survivin expression and its promoter activity. Furthermore, treatment of ovarian cancer cells with vitamin D or a selenium compound resulted in re-expression of PDEF, downregulation of survivin, induction of apoptosis and inhibition of tumor cell growth when compared to untreated controls (p < 0.05). Together, these observations showed an inverse correlation between PDEF and survivin expression and suggested that increased PDEF expression along with reduced survivin was associated with prolonged survival of patients with ovarian cancer.

Cutting edge: A transcriptional repressor and corepressor induced by the STAT3-regulated anti-inflammatory signaling pathway.

IL-10 regulates anti-inflammatory signaling via the activation of STAT3, which in turn controls the induction of a gene expression program whose products execute inhibitory effects on proinflammatory mediator production. In this study we show that IL-10 induces the expression of an ETS family transcriptional repressor, ETV3, and a helicase family corepressor, Strawberry notch homologue 2 (SBNO2), in mouse and human macrophages. IL-10-mediated induction of ETV3 and SBNO2 expression was dependent upon both STAT3 and a stimulus through the TLR pathway. We also observed that ETV3 expression was strongly induced by the STAT3 pathway regulated by IL-10 but not by STAT3 signaling activated by IL-6, which cannot activate the anti-inflammatory signaling pathway. ETV3 and SBNO2 repressed NF-kappaB- but not IFN regulatory factor 7 (IRF7)-activated transcriptional reporters. Collectively our data suggest that ETV3 and SBNO2 are components of the pathways that contribute to the downstream anti-inflammatory effects of IL-10.