Differentiation-inducing factor-1 suppresses cyclin D1-induced cell proliferation of MCF-7 breast cancer cells by inhibiting S6K-mediated signal transducer and activator of transcription 3 synthesis.

Differentiation-inducing factor-1 (DIF-1) has been reported to inhibit the proliferation of various mammalian cells by unknown means, although some possible mechanisms of its action have been proposed, including the activation of glycogen synthase kinase-3 (GSK-3). Here, we report an alternative mechanism underlying the action of DIF-1 in human breast cancer cell line MCF-7, on which the effects of DIF-1 have not been examined previously. Intragastric administration of DIF-1 reduced the tumor growth from MCF-7 cells injected into a mammary fat pad of nude mice, without causing adverse effects. In cultured MCF-7, DIF-1 arrested the cell cycle in G0 /G1 phase and suppressed cyclin D1 expression, consistent with our previous results obtained in other cell species. However, DIF-1 did not inhibit the phosphorylation of GSK-3. Investigating an alternative mechanism for the reduction of cyclin D1, we found that DIF-1 reduced the protein levels of signal transducer and activator of transcription 3 (STAT3). The STAT3 inhibitor S3I-201 suppressed cyclin D1 expression and cell proliferation and the overexpression of STAT3 enhanced cyclin D1 expression and accelerated proliferation. Differentiation-inducing factor-1 did not reduce STAT3 mRNA or reduce STAT3 protein in the presence of cycloheximide, suggesting that DIF-1 inhibited STAT3 protein synthesis. Seeking its mechanism, we revealed that DIF-1 inhibited the activation of 70 kDa and/or 85 kDa ribosomal protein S6 kinase (p70S6K /p85S6K ). Inhibition of p70S6K /p85S6K by rapamycin also reduced the expressions of STAT3 and cyclin D1. Therefore, DIF-1 suppresses MCF-7 proliferation by inhibiting p70S6K /p85S6K activity and STAT3 protein synthesis followed by reduction of cyclin D1 expression.

Suvorexant for insomnia in patients with psychiatric disorder: A 1-week, open-label study.

AIM: There have been no previous reports on the efficacy and safety of suvorexant for insomnia in people with psychiatric disorders. METHODS: This one-week, prospective, single-arm, clinical trial of fixed dose of suvorexant (20 mg if ages 18-64 or 15 mg if age ≥ 65 years) for insomnia included 57 patients with psychiatric disorders who had experienced any of the following insomnia symptoms for four or more nights during the week prior to the start of the study: total sleep time (TST) <6 hours, time to sleep onset (TSO) ≥30 minutes, or two or more episodes of wake after sleep onset. RESULTS: The mean age of the patients was 49.4 ± 17.3 years; 54.4% were women, 49.1% had a major depressive disorder, and 77.2% completed the trial. Compared with the baseline scores (the mean scores for the two days before the start of the study), taking suvorexant was associated with significant improvements in TST, TSO, wake time after sleep onset, and the patients' sleep satisfaction level at week 1. Adverse events included at least one adverse event (43.9%), sleepiness (28.8%), fatigue (11.5%), nightmares (5.8%), headache (3.8%), dizziness (3.8%), and vomiting (1.9%). CONCLUSION: Suvorexant was beneficial for the treatment of insomnia in people with psychiatric disorders. However, this study was of short duration and included only a relatively small number of patients. A larger, long-term study is needed to investigate the efficacy and safety of suvorexant for insomnia in people with psychiatric disorders.

Anti-tumor effects of differentiation-inducing factor-1 in malignant melanoma: GSK-3-mediated inhibition of cell proliferation and GSK-3-independent suppression of cell migration and invasion.

Differentiation-inducing factor-1 (DIF-1) isolated from Dictyostelium discoideum strongly inhibits the proliferation of various mammalian cells through the activation of glycogen synthase kinase-3 (GSK-3). To evaluate DIF-1 as a novel anti-cancer agent for malignant melanoma, we examined whether DIF-1 has anti-proliferative, anti-migratory, and anti-invasive effects on melanoma cells using in vitro and in vivo systems. DIF-1 reduced the expression levels of cyclin D1 and c-Myc by facilitating their degradation via GSK-3 in mouse (B16BL6) and human (A2058) malignant melanoma cells, and thereby strongly inhibited their proliferation. DIF-1 suppressed the canonical Wnt signaling pathway by lowering the expression levels of transcription factor 7-like 2 and ß-catenin, key transcription factors in this pathway. DIF-1 also inhibited cell migration and invasion, reducing the expression of matrix metalloproteinase-2; however, this effect was not dependent on GSK-3 activity. In a mouse lung tumor formation model, repeated oral administrations of DIF-1 markedly reduced melanoma colony formation in the lung. These results suggest that DIF-1 inhibits cell proliferation by a GSK-3-dependent mechanism and suppresses cell migration and invasion by a GSK-3-independent mechanism. Therefore, DIF-1 may have a potential as a novel anti-cancer agent for the treatment of malignant melanoma.

Histamine H3 Receptor Antagonists for Alzheimer's Disease: A Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Trials.

BACKGROUND: No comprehensive meta-analysis has been performed concerning the efficacy and tolerability of histamine H3 receptor antagonists (H3R-ANTs) in Alzheimer's disease patients. OBJECTIVE: We performed a systematic review and meta-analysis of double-blind randomized placebo-controlled trials (RCTs) of H3R-ANTs for Alzheimer's disease. METHODS: Relevant studies were identified through searches of PubMed, databases of the Cochrane Library, and PsycINFO citations up to June 19, 2015. The primary outcome was a change in the Mini-Mental State Examination (MMSE) scores. Secondary outcomes were Neuropsychiatric Inventory (NPI) scores, discontinuation rate, and individual adverse events/side effects. Risk ratios, numbers-needed-to-treat/harm, and standardized mean differences were calculated based on a random effects model. RESULTS: The computerized search initially yielded 33 studies after excluding duplicates. We excluded 29 of these articles following a review of titles and abstracts and one RCT including healthy subjects after full-text review. We identified three RCTs (two on GSK239512 and one on ABT-288) including 402 patients. Pooled H3R-ANTs were not superior to placebo for improvement in MMSE and NPI scores. Discontinuation rate and individual adverse events/side effects did not differ among the pooled groups. CONCLUSIONS: Our results suggest that H3R-ANTs are not effective in treating cognitive dysfunction in Alzheimer's disease. However, further studies with larger samples are required for definitive conclusions regarding responsive subpopulations.