[circDDX17 targets miR-223-3p / RIP3 to regulate the proliferation and apoptosis of non-small cell lung cancer cells]

Objective: To explore the molecular mechanism of circDDX17 regulating the proliferation and apoptosis of non-small cell lung cancer cells by targeting the miR-223-3p/RIP3 molecular axis. Methods: The expression levels of circDDX17, miR-223-3p, and RIP3 in human normal lung epithelial cell lines BEAS-2B and non-small cell lung cancer cells H1299, A549, and H446 were detected by reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR). The plasmids of pcDNA, pcDNA-circDDX17, anti-miR-con, anti-miR-223-3p, pcDNA-circDDX17 and miR-con, pcDNA-circDDX17 and miR-223-3p mimics were transfected into H1299 cells. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide (MTT) assay was used to detect the cell proliferation. Flow cytometry was used to detect the cell cycle and cell apoptosis. Plate cloning experiment was used to detect cell proliferation ability. The dual luciferase report experiment was applied to verify the targeting relationship between miR-223-3p with circDDX17 and RIP3. Western blot was used to detect the protein expression of cyclinD1, CDK2, cleaved caspase-3 and Bax. Results: The expression levels of circDDX17 and RIP3 mRNA in H1299, A549, and H446 cells were significantly reduced (P<0.05), the expression level of miR-223-3p mRNA was significantly increased (P<0.05) compared with BEAS-2B. The cell viability [(69.46±4.68)%], the number of cell clones (83.49±7.86), the proportion of cells in S phase [(22.52±1.41) %], the protein expression levels of cyclinD1 and CDK2 in PCDNa-CircDDX17 group were lower than those in pcDNA group [(97.54±7.72)%, 205.03±13.37, (28.69±1.49)%, respectively, P<0.05], while the percentage of G0/G1 phase cells [(64.45±3.56)%], apoptosis rate [(18.36±1.63)%], the protein expression levels of cleaved caspase-3 and Bax in pcDNA-circDDX17 group were higher than those of pcDNA group [(51.33±2.76) % and (5.21±0.54) %, respectively, P<0.05]. The viability [(72.64±5.44)%], the number of cell clones (78.16±8.23), the proportion of S-stage cells [(21.34±1.59) %], the protein expression levels of CyclinD1 and CDK2 in anti-miR-223-3p group were lower than those in anti-miR-con group [(103.47±6.25)%, 169.32±14.53, (28.43±1.26)%, respectively, P<0.05]. Percentage of G0/G1 phase cells [(62.86±3.28)%], apoptosis rate [(14.64±1.67)%], the protein expression levels of cleaved caspase-3 and Bax in the anti-miR-223-3p group were higher than those of anti-miR-con group [(51.33±2.71)% and (4.83±0.39)%, respectively, P<0.05]. MiR-223-3p has complementary sites with circDDX17 or RIP3. The viability [(135.45±9.28)%], the number of cell clones (174.64±10.68), the proportion of S-phase cells [(26.39±2.25)%], the protein expression levels of cyclinD1 and CDK2 in pcDNA-circDDX17+miR-223-3p group were higher than those in pcDNA-circDDX17+miR-con group [(101.56±6.68)%, 107.65±7.62, (21.64±1.72)%, P<0.05]. Percentage of G0/G1 phase cells [(56.64±2.76)%], apoptosis rate [(8.34±0.76)%], the protein expression levels of cleaved caspase-3 and Bax in pcDNA-circDDX17+miR-223-3p group were lower than those of pcDNA-circDDX17+miR-con group [(64.03±3.48)% and (15.21±1.18)%, respectively, P<0.05]. Conclusion: circDDX17 could inhibit the proliferation and induce apoptosis of non-small cell lung cancer cells via targeting the miR-223-3p / RIP3 molecular axis.

A Novel Small Molecular Inhibitor of DNMT1 Enhances the Antitumor Effect of Radiofrequency Ablation in Lung Squamous Cell Carcinoma Cells

Radiofrequency ablation (RFA) is a relatively new and effective therapeutic strategy for treating lung squamous cell carcinomas (LSCCs). However, RFA is rarely used in the clinic for LSCC which still suffers from a lack of effective comprehensive treatment strategies. In the present work, we investigate iDNMT, a novel small molecular inhibitor of DNMT1 with a unique structure. In clinical LSCC specimens, endogenous DNMT1 was positively associated with methylation rates of miR-27-3p's promoter. Moreover, endogenous DNMT1 was negatively correlated with miR-27-3p expression which targets PSEN-1, the catalytic subunit of γ-secretase, which mediates the cleavage and activation of the Notch pathway. We found that DNMT1 increased activation of the Notch pathway in clinical LSCC samples while downregulating miR-27-3p expression and hypermethylation of miR-27-3p's promoter. In addition of inhibiting activation of the Notch pathway by repressing methylation of the miR-27-3p promoter, treatment of LSCC cells with iDNMT1 also enhanced the sensitivity of LSCC tumor tissues to RFA treatment. These data suggest that iDNMT-induced inhibition of DNMT-1 enhances miR-27-3p expression in LSCC to inhibit activation of the Notch pathway. Furthermore, the combination of iDNMT and RFA may be a promising therapeutic strategy for LSCC.

Berberine activates the β-catenin/TCF4 signaling pathway by down-regulating miR-106b to promote GLP-1 production by intestinal L cells

Berberine facilitates the production of glucagon-like peptide-1 (GLP-1) by intestinal L cells. Here, we aimed to reveal the mechanism of berberine facilitating the production of GLP-1 by intestinal L cells. In this study, we confirmed that the 100 mg/kg berberine daily through diet decreased the miR-106b expression and elevated the expressions of β-catenin and T-cell factor 4 (TCF4) in colon tissues of high-fat diet mice; berberine decreased the concentrations of triglycerides, total cholesterol and the ratio of low-density lipoprotein cholesterol and high-density lipoprotein cholesterol in mouse serum samples; berberine decreased the blood glucose in the mouse tail vein blood and promoted GLP-1 production by intestinal L cells in mouse serum samples and elevated the GLP-1 expression in mouse colon tissues. Meanwhile, the mechanism analysis demonstrated that a dose of 100 μM berberine down-regulated the miR-106b expression by elevating the methylation levels of miR-106b in STC-1 cells and miR-106b bound to TCF4 in 293T cells. Moreover, the 100 mg/kg berberine daily through diet activated the β-catenin/TCF4 signaling pathway by decreasing miR-106b, thereby facilitating GLP-1 production in intestinal L cells through the in vivo assays. Conclusively, our experimental data illustrated that berberine decreased miR-106b expression by increasing its methylation levels and then activated the β-catenin/TCF4 signaling pathway, thereby facilitating GLP-1 production by intestinal L cells.

Metabolic profiling of nanosilver toxicity in the gills of common carp

Studies have shown silver nanoparticles (AgNPs) exposure can result in a series of toxic effects in fish gills. However, it is still unclear how AgNPs affect metabolite expression and their related molecular metabolic pathways in fish gills. In this study, we employed untargeted metabolomics to study the effects of AgNPs and silver supernatant ions on fish gill metabolites. The results showed that AgNPs can induce significant changes in 96 differentially expressed metabolites, which mainly affect amino acid metabolism and energy metabolism in fish gills. Among these metabolites, AgNPs specifically induce significant changes in 72 differentially expressed metabolites, including L-histidine, L-isoleucine, L-phenylalanine, and citric acid. These metabolites were significantly enriched in the pathways of aminoacyl-tRNA biosynthesis, ABC transporters, and the citrate cycle. In contrast, Ag⁺ supernatant exposure can specifically induce significant changes in 14 differentially expressed metabolites that mainly interfere with sphingolipid metabolism in fish gills. These specifically regulated fish gill metabolites include sphinganine, sphingosine, and phytosphingosine, which were significantly enriched in the sphingolipid metabolism pathway. Our results clearly reveal the effects and potential toxicity mechanisms of AgNPs on fish gill metabolites. Furthermore, our study further determined the unique functions of released silver ions in AgNPs toxicity in fish gills.

Effect of silver nanoparticles on gill membranes of common carp: Modification of fatty acid profile, lipid peroxidation and membrane fluidity

Although the toxicity of silver nanoparticles (AgNPs) in aquatic organisms has been extensively investigated, the mechanism by which AgNPs damage membranes remains unclear. This study investigated the toxic effects of a series of sub-lethal concentrations of AgNPs on the membranes of freshwater carp (Cyprinus carpio) gills, based on changes in membrane fatty acid (FA) profile, membrane fluidity, membrane lipid peroxidation, and histopathology. Most of the FAs in fish gill membrane was not significantly affected by exposure to multiple AgNPs concentrations, only few significant changes occurred in some specific FAs species at a high concentration of AgNPs exposure. In particular, high concentrations of AgNPs significantly decreased the proportions of two important long-chain n-3 series polyunsaturated FAs (C20: 5n3, and C22: 6n3), resulting in a decreased ratio of n-3 polyunsaturated FAs to n-6 polyunsaturated FAs (Σn-3UFA/Σn-6UFA). The AgNPs also caused a dose-dependent decrease in fish gill membrane fluidity, increased the level of lipid peroxidation, and inhibited Na⁺/K⁺-ATPase enzyme activity. Further histopathological examination revealed that exposure to AgNPs can cause toxic responses in the lamellae, including the thinning of the basement membrane, malformation, and inflammation. Together, the results suggest that the mechanism of AgNPs membrane toxicity involves the oxidization of long-chain omega-3 unsaturated FAs to saturated FAs via lipid peroxidation, resulting in, decreased membrane fluidity and ultimately the destruction of the normal physiological function of the fish gill membrane. The findings contribute significantly to our understanding of nanoparticle-induced membrane toxicity and potential risks in aquatic environments.

High glucose contributes to the proliferation and migration of non-small cell lung cancer cells via GAS5-TRIB3 axis

Despite the growing number of studies exhibited an association of diabetes mellitus (DM) and lung cancer progression, the concrete mechanism of DM aggravating lung cancer has not been elucidated. This study was to investigate whether and how high glucose (HG) contribute to the proliferation and migration of non-small cell lung cancer (NSCLC) cells in vitro. In the present study, we confirmed that HG promoted the proliferation and migration of NSCLC cells, and also induced an anti-apoptosis effect on NSCLC cells. Moreover, HG inhibited the expression of GAS5 in NSCLC cells but elevated the protein level of TRIB3. GAS5 overexpression promoted the degradation of TRIB3 protein by ubiquitination and inhibited the HG induced-proliferation, anti-apoptosis and migration of NSCLC cells. Importantly, TRIB3 overexpression reversed the effects of GAS5 on the HG-treated NSCLC cells. Taken together, down-regulated GAS5 by HG significantly enhanced the proliferation, anti-apoptosis and migration in NSCLC cells through TRIB3, thus promoting the carcinogenesis of NSCLC.

[Expression of microRNA-146a in lipopolysaccharide challenged alveolar macrophages in vitro]

OBJECTIVE

To investigate the expression of microRNA-146a (miRNA-146a) in NR8383 alveolar macrophages treated with lipopolysaccharides (LPS).

METHODS

NR8383 alveolar macrophages were divided into two groups: LPS treated group and phosphate buffer saline (PBS) control group, and they cultured for 6 hours. The production of tumor necrosis factor-α (TNF-α) in the supernatant of cells was determined with enzyme-linked immunosorbent assay (ELISA), and the expression of miRNA-146a of cells was detected by real-time polymerase chain reaction (PCR).

RESULTS

Compared with PBS control group, the TNF-α content (ng/L) in LPS treated group was significantly increased (650.26±40.53 vs. 6.23±1.76, P<0.01), and miRNA-146a in LPS treated group increased by about (5.33±0.81) folds (P<0.01).

CONCLUSION

The expression of miRNA-146a was increased in LPS treated NR8383 cells, and miRNA-146a may be involved in the modulation inflammatory response of the NR8383 alveolar macrophage.

Discovery of (R)-7-cyano-2,3,4, 5-tetrahydro-1-(1H-imidazol-4-ylmethyl)-3- (phenylmethyl)-4-(2-thienylsulfonyl)-1H-1,4-benzodiazepine (BMS-214662), a farnesyltransferase inhibitor with potent preclinical antitumor activity

Continuing structure-activity studies were performed on the 2,3,4, 5-tetrahydro-1-(imidazol-4-ylalkyl)-1,4-benzodiazepine farnesyltransferase (FT) inhibitors. These studies demonstrated that a 3(R)-phenylmethyl group, a hydrophilic 7-cyano group, and a 4-sulfonyl group bearing a variety of substituents provide low-nanomolar FT inhibitors with cellular activity at concentrations below 100 nM. Maximal in vivo activity in the mutated K-Ras bearing HCT-116 human colon tumor model was achieved with analogues carrying hydrophobic side chains such as propyl, phenyl, or thienyl attached to the N-4 sulfonyl group. Several such compounds achieved curative efficacy when given orally in this model. On the basis of its excellent preclinical antitumor activity and promising pharmacokinetics, compound 20 (BMS-214662, (R)-7-cyano-2,3,4, 5-tetrahydro-1-(1H-imidazol-4-ylmethyl)-3-(phenylmethyl)-4-(2-thie nyl sulfonyl)-1H-1,4-benzodiazepine) has been advanced into human clinical trials.

3-Imidazolylmethylaminophenylsulfonyltetrahydroquinolines, a novel series of farnesyltransferase inhibitors

Design, synthesis and structure-activity relationship of a series of 3-imidazolylmethylaminophenylsulfonyltetrahydroquinolines as farnesyltransferase inhibitors are presented. A working pharmacophore of inhibiting farnesyltransferase by this series of inhibitors is proposed.

Discovery and structure-activity relationships of imidazole-containing tetrahydrobenzodiazepine inhibitors of farnesyltransferase

2,3,4,5-Tetrahydro-1-(imidazol-4-ylalkyl)-1,4-benzodiazepines were found to be potent inhibitors of farnesyltransferase (FT). A hydrophobic substituent at the 4-position of the benzodiazepine, linked via a hydrogen bond acceptor, was important to enzyme inhibitory activity. An aryl ring at position 7 or a hydrophobic group linked to the 8-position through an amide, carbamate, or urea linkage was also important for potent inhibition. 2,3,4, 5-Tetrahydro-1-(1H-imidazol-4-ylmethyl)-7-(4-pyridinyl)-4-[2-(t rifluo romethoxy)benzoyl]-1H-1,4-benzodiazepine (36), with an FT IC(50) value of 24 nM, produced 85% phenotypic reversion of Ras transformed NIH 3T3 cells at 1.25 microM and had an EC(50) of 160 nM for inhibition of anchorage-independent growth in soft agar of H-Ras transformed Rat-1 cells. Selected analogues demonstrated ip antitumor activity against an ip Rat-1 tumor in mice.

Cardioselective antiischemic ATP-sensitive potassium channel (K(ATP)) openers. 6. Effect of modifications at C6 of benzopyranyl cyanoguanidines

The effect on potency and selectivity of modifications at the C6 position of the cardioprotective K(ATP) opener BMS-180448 (2) is described. Structure-activity studies show that a variety of electron-withdrawing groups (ketone, sulfone, sulfonamide, etc.) are tolerated for cardioprotective activity as measured by EC(25) values for an increase in time to the onset of contracture in globally ischemic rat hearts. Changes made to the sulfonamido substituent indicate that compounds derived from secondary lipophilic amines are preferred for good cardioprotective potency and selectivity. The diisobutyl analogue 27 (EC(25) = 0.04 microM) is the most potent compound of this series. The cardiac selectivity of 27 results from a combination of reduced vasorelaxant potency and enhanced cardioprotective potency relative to the potent vasodilating K(ATP) openers (e.g., cromakalim). The diisobutylsulfonamide analogue 27 is over 4 orders of magnitude more cardiac selective than cromakalim (1). These results support the hypothesis that the cardioprotective and vasorelaxant properties of K(ATP) openers follow distinct structure-activity relationships. The mechanism of action of 27 appears to involve opening of the cardiac K(ATP) as its cardioprotective effects are abolished by the K(ATP) blocker glyburide.

Inactivation of monoamine oxidase B by benzyl 1-(aminomethyl) cyclopropane-1-carboxylate

Monoamine oxidase (MAO) is a flavoenzyme that catalyzes the oxidation of various biogenic and xenobiotic amines. Benzyl 1-(aminomethyl)cyclopropane-1-carboxylate (1) was designed as a diactivated cyclopropane mechanism-based inactivator of MAO (Silverman, R.B.: Ding, C.Z.; Borrillo, J.L.; Chang, J.T.J. Am. Chem. Soc. 1993, 115, 2982). [1,1-2H2]-1 exhibits a deuterium isotope effect of 4.5 on inactivation, but in D2O the isotope effect is only 2.3. [1-3H]-1 and [1-14C]-1 were synthesized; upon inactivation of MAO, 1.1 and 2.0 equiv of radioactivity, respectively, are incorporated into the enzyme. Tritium as 3H2O, is released during inactivation with [1-3H]-1. The flavin absorption spectrum changes from that of oxidized to that of reduced flavin after inactivation; denaturation of the inactivated enzyme shows a reduced flavin spectrum, suggesting the formation of a modified flavin. Tryptic digestion of the enzyme labeled with [1-3H]-1 or [1-14C]-1, followed by HPLC analysis, monitoring at 310 nm [corrected] (flavin), shows that the radioactivity comigrates with the 310 nm [corrected] absorptions. The metabolites that are generated during inactivation are benzyl 1-formylcyclopropane-1-carboxylate, benzyl alcohol, and 1-formylcyclopropane-1-carboxylic acid; no ring-cleaved products were detected. The partition ratio, as determined from the ratio of nonamines to enzyme, is 110. These results are rationalized in terms of a single-electron transfer mechanism leading to the imine of benzyl 1-formylcyclopropane-1-carboxylate, which alkylates the flavin coenzyme.

Cardioselective antiischemic ATP-sensitive potassium channel (KATP) openers. 5. Identification of 4-(N-aryl)-substituted benzopyran derivatives with high selectivity

This paper describes our studies aimed at the discovery of structurally distinct analogs of the cardioprotective KATP opener BMS-180448 (2) with improved selectivity for the ischemic myocardium. The starting compound 6, derived from the indole analog 4. showed good cardioprotective potency and excellent selectivity compared to 2 and the first-generation KATP opener cromakalim (1). The structure-activity studies indicate that increasing the size of the alkyl ester leads to diminished potency as does its replacement with a variety of other groups (nitrile, methyl sulfone). Replacement of the ethyl ester of 6 with an imidazole gave the best compound 3 (BMS-191095) of this series which maintains the potency and selectivity of its predecessor 6. The results described in this publication further support that there is no correlation between vasorelaxant and cardioprotective potencies of KATP openers. Compound 3 is over 20- and 4000-fold more selective for the ischemic myocardium than 2 and cromakalim (1), respectively. The selectivity for the ischemic myocardium is achieved by reduction of vasorelaxant potency rather than enhancement in antiischemic potency. As for cromakalim (1) and 2, the cardioprotective effects of compound 3 are inhibited by cotreatment with the KATP blocker glyburide, indicating that the KATP opening is involved in its mechanism of cardioprotection. With its good oral bioavailability (47%) and plasma elimination half-life (3 h) in rats, compound 3 offers an excellent candidate to investigate the role of residual vasorelaxant potency of 2 toward its cardioprotective activity in vivo.

Cardioselective antiischemic ATP-sensitive potassium channel openers. 4. Structure-activity studies on benzopyranylcyanoguanidines: replacement of the benzopyran portion

The results of our efforts aimed at the replacement of the benzopyran ring of the lead cardiac selective antiischemic ATP-sensitive potassium channel (KATP) opener (4) are described. Systematic modification of the benzopyran ring of 4 resulted in the discovery of a structurally simpler acyclic analog (8) with slightly lower antiischemic potency than the lead compound 4. Further structure-activity studies on the acyclic analog 8 provided the 2-phenoxy-3-pyridylurea analog 18 with improved antiischemic potency and selectivity compared to the benzopyran-based compound 4. These data demonstrate that the benzopyran ring of 4 and its congeners is not mandatory for antiischemic activity and cardiac selectivity. The results described in this paper also show that, as for the benzopyran class of compounds, the structure-activity relationships for the antiischemic and vasorelaxant activities of KATP openers are distinct. The mechanism of action of the acyclic analogs (e.g., 18) still appears to involve KATP opening as their cardioprotective effects are abolished by pretreatment with the KATP blocker glyburide.

Transformation of heterocyclic reversible monoamine oxidase-B inactivators into irreversible inactivators by N-methylation

3-[4-[(3-Chlorophenyl)methoxy]phenyl]-5-[(methylamino)methyl]- 2-oxazolidinone (1) is a secondary amine known to be a potent time-dependent irreversible inactivator of monoamine oxidase B (MAO-B). The primary amine analogues of derivatives of 1, as well as of the corresponding dihydrofuranone and pyrrolidinone, had been shown to be time-dependent, but reversible, inhibitors of MAO-B. Here it is shown that the primary amine analogue of 1 is a time-dependent reversible inhibitor of MAO-B and that the secondary and tertiary amine analogues of the corresponding oxazolidinone, dihydrofuranone, and pyrrolidinone are time-dependent irreversible inhibitors of MAO-B. The reaction leading to the irreversible enzyme adduct formation with 1 can be reversed by increasing the temperature. These results are consistent with a stabilizing stereoelectronic effect on the enzyme adduct caused by N-methylation which hinders free rotation and prevents the sp3-orbital containing the nitrogen nonbonded electrons from being trans to the active site amino acid leaving group.

Transformation of monoamine oxidase-B primary amine substrates into time-dependent inhibitors. Tertiary amine homologues of primary amine substrates

A family of N-methylated and N,N-dimethylated alkyl and arylalkylamines was prepared and more than half of the analogues were shown to be time-dependent pseudo-first-order inhibitors of monoamine oxidase-B. Some of the time-dependent inactivators were reversible and others were irreversible with respect to prolonged dialysis following inactivation. Partition ratios ranged from zero to 11,000. These results are rationalized in terms of a combination of an inductive effect and a stereoelectronic effect as a result of hindered rotation of an active site covalent adduct. A molecular mechanics calculation indicates that there is at least 10 kcal/mol of torsional energy to be overcome in order for the enzyme adduct to be released. These findings show that tertiary amine homologues of primary amine substrates of monoamine oxidase are time-dependent inhibitors, and this should be useful in the design of new inactivators of this enzyme.

4-(Aminomethyl)-1-aryl-2-pyrrolidinones, a new class of monoamine oxidase B inactivators

Both 4-(aminomethyl)-1-phenyl-2-pyrrolidinone (4a) and 4-(aminomethyl)-1- (methoxyphenyl)-2-pyrrolidinone (4b) hydrochlorides were synthesized via a six-step sequence, which represents a general approach to 1,4-disubstituted 2-pyrrolidinones. Both of these compounds inactivated monoamine oxidase B and represent the first in a new class of monomamine oxidase inactivators.