To investigate the effect of a microsomal prostaglandin E synthase-1 (mPGES-1) inhibitor MK886 on cell cycle of the human acute myeloid leukemia HL-60 cells. HL-60 cells were treated with different concentration of MK886 (10, 25, 50 µmol/L) for 24 h. Flow cytometry, Western blot and ELISA were used to measure cell cycle, cyclin D1, mPGES-1, PGE(2), Akt, P-Akt and C-MYC. The results indicated that after treated with MK886, the percentage of HL-60 cells decreased in G(0)/G(1) phase and increased in S phase, and expressions of mPGES-1, cyclin D1, P-Akt and C-MYC and synthesis of PGE(2) decreased significantly. It is concluded that MK886 can arrest HL-60 cells in G(0)/G(1) phase, the mechanism of which is possibly associated to inhibition of mPGES-1 expression, reduction of PGE(2) synthesis, suppression of Akt phosphorylation and C-MYC expression, down-regulation of cyclin D1 expression.
Cell Cycle ; drug effects ; HL-60 Cells ; Humans ; Indoles ; pharmacology ; Intramolecular Oxidoreductases ; antagonists & inhibitors ; Leukemia ; metabolism ; pathology ; Prostaglandin-E Synthases

Objective To investigate the effect of 15-Deoxy-△(12,14)-prostaglandin J2 (15 d-PGJ2) on the expression of macrophage migration inhibitory factor (MIF) and its underlying mechanism in J774A.1. Methods The murine monocyte/macrophage cell line J774A.1 were divided into six groups:lipopolysaccharide (LPS) group,incubated with 1 μg/ml LPS for 1 h;normal control group,incubated with PBS for 1 h;negative control group,incubated with 5 μmol/L 15 d-PGJ2 for 1 h;15 d-PGJ2 group,incubated with 5 μmol/L 15 d-PGJ2 for 1 h followed by 1 μg/ml LPS for 1 h;GW9662 group,incubated with 5 μmol/L 15 d-PGJ2 for 1 h following GW9662 10 μmol/L for 1 h,and then incubated with 1 μg/ml LPS for 1 h;and Vehicle group,control of GW9662,GW9662 was replaced by its solvent DMSO. The expression of MIF was detected via immunofluorescence and agarose gel electrophoresis. RT-qPCR and Western blotting were used to test whether 15 d-PGJ2 could regulate mRNA and protein expression of MIF in J774A.1 upon LPS challenge. The effect of peroxisome proliferator-activated receptor-γ (PPAR-γ) antagonist GW9662 on the regulation of MIF by 15 d-PGJ2 was observed. The effects of 15 d-PGJ2 on the nuclear translocation of PPAR-γ upon LPS challenge were detected via high content screening analysis. Results MIF DNA and protein expressions were detected in J774A.1. MIF mRNA expression was up-regulated (1.75±0.09,P=0.037) when challenged with LPS and 15 d-PGJ2 inhibited its upregulation (0.84±0.08,P=0.026) in J774A.1. The protein level was consistent with the mRNA level. PPAR-γ antagonist GW9662 reversed the effect of 15 d-PGJ2 (mRNA,1.48±0.06,P=0.016;protein,1.28). Furthermore,nuclear translocation of PPAR-γ was regulated by 15 d-PGJ2 in J774A.1 upon LPS challenge(1.39±0.02 vs. 1.01±0.03,P=0.003). Conclusion 15 d-PGJ2 may down-regulate the MIF expression in J774A.1 in a PPAR-γ-dependent manner.
Anilides ; pharmacology ; Animals ; Cell Line ; Intramolecular Oxidoreductases ; metabolism ; Lipopolysaccharides ; Macrophage Migration-Inhibitory Factors ; metabolism ; Mice ; Monocytes ; drug effects ; PPAR gamma ; antagonists & inhibitors ; Prostaglandin D2 ; analogs & derivatives ; pharmacology

Xanthohumol (XH), the principal prenylflavonoid of the hop plant (Humulus lupulus L.), dose-dependently inhibited isobutylmethylxanthine (IBMX)-induced melanogenesis in B16 melanoma cells, with little cytotoxicity at the effective concentrations. Decreased melanin content was accompanied by reduced tyrosinase enzyme activity, protein and mRNA expression. The levels of tyrosinase-related protein 1 and 2 mRNAs were decreased by XH. XH also inhibited alpha-melanocyte stimulating hormone- or forskolin-induced increases in melanogenesis, suggesting an action on the cAMP-dependent melanogenic pathway. XH downregulated the protein and mRNA expression of microphthalmia-associated transcription factor (MITF), a master transcriptional regulator of key melanogenic enzymes. These results suggest that XH might act as a hypo-pigmenting agent through the downregulation of MITF in the cAMP-dependent melanogenic pathway.
1-Methyl-3-isobutylxanthine/pharmacology ; Animals ; Cell Line ; Cell Survival/drug effects ; Dose-Response Relationship, Drug ; Down-Regulation ; Drug Antagonism ; Forskolin/pharmacology ; *Humulus ; Intramolecular Oxidoreductases/antagonists & inhibitors/biosynthesis ; Melanins/antagonists & inhibitors/*biosynthesis ; Melanocytes/*drug effects/*metabolism ; Melanoma, Experimental ; Membrane Glycoproteins/antagonists & inhibitors/biosynthesis ; Mice ; Microphthalmia-Associated Transcription Factor/antagonists & inhibitors ; Monophenol Monooxygenase/antagonists & inhibitors/biosynthesis/genetics ; Oxidoreductases/antagonists & inhibitors/biosynthesis ; Propiophenones/*pharmacology ; Signal Transduction/drug effects ; alpha-MSH/metabolism

The aim of this study was to, from the point of neurogenic inflammation, explore the pathogenesis of colitis and to provide direct evidence for the neurogenic colitis hypothesis. Male Sprague-Dawley rats (180-220 g) anesthetized with chloral hydrate were intrathecally (ith) implanted with polyethylene-10 (PE-10) catheter to reach the spinal cord T₁₂-L₅ level. Substance P (SP) was ith injected once a day for 14 d. The disease active index (DAI) score was calculated by rat body weight and stool. The macroscopic and HE staining-microscopic pathologies of colon/spinal tissue were evaluated. By immunofluorescence staining, the protein expression of a pro-inflammatory cytokine, migration inhibitory factor (MIF), in colon tissue was detected and was semi-quantitatively analyzed. The results showed that in the colon tissue, inflammation was dose-dependently aggravated by ith SP 10 μ and 20 μ, whereas in the spinal tissue, only slight edema and congestion were seen in SP 20 μ group. The MIF protein of colon tissue was increased in ith SP 10 μ and 20 μ groups (P<0.05, P<0.01 as compared to normal saline group respectively), but in the spinal tissue, there was no obvious MIF protein expression either in SP groups or in normal saline group. Pretreatment with neurokinin-1 (NK₁) receptor antagonist ([D-Pro2, D-Trp7, 9] -SP, 22.4 μ, ith, 10 min before ith SP) prolonged the latency of DAI rising and reduced the DAI amplitude, as well as prevented the high MIF expression induced by ith SP. These results suggest that rat colitis can be induced by direct SP stimulation in lumbar spine via activating central NK₁ receptor; and that colonic MIF is possibly one of the inflammatory factors involved in this pathogenesis. These data provide a reasonable support to the hypothesis of colitis being a neurogenic inflammation. In addition, a potential clinical significance for the finding that higher concentration of spinal SP can induce colitis via NK₁ receptor is discussed.
Animals ; Colitis ; chemically induced ; Colon ; pathology ; Disease Models, Animal ; Inflammation ; pathology ; Injections, Spinal ; Intramolecular Oxidoreductases ; metabolism ; Macrophage Migration-Inhibitory Factors ; metabolism ; Male ; Neurokinin-1 Receptor Antagonists ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptors, Neurokinin-1 ; metabolism ; Spinal Cord ; pathology ; Substance P ; adverse effects