PTP1B inhibitors from stems of Angelica keiskei (Ashitaba).

Three new chalcones, xanthoangelols K-M (1-3), together with 19 known compounds were isolated from the stems of Angelica keiskei Koidzumi, a well-known rejuvenated and anti-diabetic plant originated from Japan. The structures of compounds 1-3 were elucidated on the basis of spectroscopic data and Mosher's method. All compounds were evaluated for their inhibitory activity against protein tyrosine phosphatase 1B (PTP1B). Among them, six chalcones, xanthoangelol K (1), xanthoangelol (4), xanthoangelol F (5), 4-hydroxyderricin (6), xanthoangelol D (7), xanthoangelol E (8), and a coumarin, methoxsalen (17), showed strong PTP1B inhibitory effect with IC50 values of 0.82, 1.97, 1.67, 2.47, 3.97, 1.43, and 2.53µg/mL, respectively. A kinetic study revealed that compound 1 inhibited PTP1B with characteristics typical of a competitive inhibitor. Molecular docking simulations elucidated that ring B of 1 may anchor in a pocket of PTP1B and the molecule is stabilized by hydrogen bonds with Arg47, Asp48, and π-π interaction with Phe182 of PTP1B.

2-(3-Benzoylthioureido)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylic acid ameliorates metabolic disorders in high-fat diet-fed mice.

AIM: Sterol-regulatory element binding proteins (SREBPs) are major transcription factors that regulate liver lipid biosynthesis. In this article we reported a novel synthetic compound 2-(3-benzoylthioureido)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylic acid (ZJ001) that inhibited the SREBP-1c pathway, and effectively reduced hepatic lipid accumulation in diet-induced obesity (DIO) mice. METHODS: A luciferase reporter driven by an SRE-containing promoter transfected into HepG2 cells was used to discover the compound. Two approaches were used to evaluate the lipid-lowering effects of ZJ001: (1) diet-induced obesity (DIO) mice that were treated with ZJ001 (15 mg·kg(-1)·d(-1), po) for 7 weeks; and (2) HepG2 cells and primary hepatocytes used as in vitro models. RESULTS: ZJ001 (10, 20 µmol/L) dose-dependently inhibited the activity of SRE-containing promoter. ZJ001 administration ameliorated lipid metabolism and improved glucose tolerance in DIO mice, accompanied by significantly reduced mRNA levels of SREBP-1C and SREBP-2, and their downstream genes. In HepG2 cells and insulin-treated hepatocytes, ZJ001 (10-40 µmol/L) dose-dependently inhibited lipid synthesis, and reduced mRNA levels of SREBP-1C and SREBP-2, and their downstream genes. Furthermore, ZJ001 dose-dependently increased the phosphorylation of AMPK and regulatory-associated protein of mTOR (Raptor), and suppressed the phosphorylation of mTOR in insulin-treated hepatocytes. Moreover, ZJ001 increased the ADP/ATP ratio in insulin-treated hepatocytes. CONCLUSION: ZJ001 exerts multiple beneficial effects in diet-induced obesity mice. Its lipid-lowering effects may result from the suppression of mTORC1, which regulates SREBP-1c transcription. The results suggest that the SREBP-1c pathway may be a potential therapeutic target for the treatment of lipid metabolic disorders.

Autophagy Accompanied with Bisdemethoxycurcumin-induced Apoptosis in Non-small Cell Lung Cancer Cells.

OBJECTIVE: To investigate the effects of bisdemethoxycurcumin (BDMC) on non-small cell lung cancer (NSCLC) cell line, A549, and the highly metastatic lung cancer 95D cells. METHODS: CCK-8 assay was used to assess the effect of BDMC on cytotoxicity. Flow cytometry was used to evaluate apoptosis. Western blot analysis, electron microscopy, and quantification of GFP-LC3 punctuates were used to test the effect of BDMC on autophagy and apoptosis of lung cancer cells. RESULTS: BDMC inhibited the viability of NSCLC cells, but had no cytotoxic effects on lung small airway epithelial cells (SAECs). The apoptotic cell death induced by BDMC was accompanied with the induction of autophagy in NSCLC cells. Blockage of autophagy by the autophagy inhibitor 3-methyladenine (3-MA) repressed the growth inhibitory effects and induction of apoptosis by BDMC. In addition, BDMC treatment significantly decreased smoothened (SMO) and the transcription factor glioma-associated oncogene 1 (Gli1) expression. Furthermore, depletion of Gli1 by siRNA and cyclopamine (a specific SMO inhibitor) induced autophagy. CONCLUSION: Aberrant activation of Hedgehog (Hh) signaling has been implicated in several human cancers, including lung cancers. The present findings provide direct evidence that BDMC-induced autophagy plays a pro-death role in NSCLC, in part, by inhibiting Hedgehog signaling.

Synthesis and biological evaluation of novel bis-aromatic amides as novel PTP1B inhibitors.

A series of bis-aromatic amides was designed, synthesized, and evaluated as a new class of inhibitors with IC50 values in the micromolar range against protein tyrosine phosphatase 1B (PTP1B). Among them, compound 15 displayed an IC50 value of 2.34±0.08 µM with 5-fold preference over TCPTP. More importantly, the treatment of CHO/HIR cells with compound 15 resulted in increased phosphorylation of insulin receptor (IR), which suggested extensive cellular activity of compound 15. These results provided novel lead compounds for the design of inhibitors of PTP1B as well as other PTPs.

Design and synthesis of paracaseolide A analogues as selective protein tyrosine phosphatase 1B inhibitors.

A series of structurally related analogues of the natural product paracaseolide A were synthesized and identified as potent PTP1B inhibitors. Among these analogues, compound 10 in particular showed improved PTP1B enzyme inhibitory activity, high selectivity for PTP1B over TC-PTP, and improved cellular effects.

4-Quinolone-3-carboxylic acids as cell-permeable inhibitors of protein tyrosine phosphatase 1B.

Protein tyrosine phosphatase 1B is a negative regulator in the insulin and leptin signaling pathways, and has emerged as an attractive target for the treatment of type 2 diabetes and obesity. However, the essential pharmacophore of charged phosphotyrosine or its mimetic confer low selectivity and poor cell permeability. Starting from our previously reported aryl diketoacid-based PTP1B inhibitors, a drug-like scaffold of 4-quinolone-3-carboxylic acid was introduced for the first time as a novel surrogate of phosphotyrosine. An optimal combination of hydrophobic groups installed at C-6, N-1 and C-3 positions of the quinolone motif afforded potent PTP1B inhibitors with low micromolar IC50 values. These 4-quinolone-3-carboxylate based PTP1B inhibitors displayed a 2-10 fold selectivity over a panel of PTP's. Furthermore, the bidentate inhibitors of 4-quinolone-3-carboxylic acids conjugated with aryl diketoacid or salicylic acid were cell permeable and enhanced insulin signaling in CHO/hIR cells. The kinetic studies and molecular modeling suggest that the 4-quinolone-3-carboxylates act as competitive inhibitors by binding to the PTP1B active site in the WPD loop closed conformation. Taken together, our study shows that the 4-quinolone-3-carboxylic acid derivatives exhibit improved pharmacological properties over previously described PTB1B inhibitors and warrant further preclinical studies.

1H-2,3-dihydroperimidine derivatives: a new class of potent protein tyrosine phosphatase 1B inhibitors.

A series of 1H-2,3-dihydroperimidine derivatives was designed, synthesized, and evaluated as a new class of inhibitors of protein tyrosine phosphatase 1B (PTP1B) with IC50 values in the micromolar range. Compounds 46 and 49 showed submicromolar inhibitory activity against PTP1B, and good selectivity (3.48-fold and 2.10-fold respectively) over T-cell protein tyrosine phosphatases (TCPTP). These results have provided novel lead compounds for the design of inhibitors of PTP1B as well as other PTPs.

Synthesis and biological evaluation of 4,4-dimethyl lithocholic acid derivatives as novel inhibitors of protein tyrosine phosphatase 1B.

Protein tyrosine phosphatase 1B (PTP1B) is a major negative regulator of both insulin and leptin signals. For years, inhibiting of PTP1B has been considered to be a potential therapeutics for treating Type 2 diabetes and obesity. Recently, we recognized lithocholic acid (LCA) as a natural inhibitor against PTP1B (IC(50)=12.74 µM) by a vertical screen for the first time. Further SAR research was carried out by synthesizing and evaluating a series of compounds bearing two methyls at C-4 position and a fused heterocycle to ring A. Among them, compound 14b achieved a PTP1B inhibitory activity about eightfold than LCA and a 14-fold selectivity over the homogenous enzyme TCPTP.

[Expression and significance of P311 and ITGB4BP in non-small cell lung cancer].

OBJECTIVE: The aim of this study was to investigate the expression and significance of P311 and ITGB4BP in non-small cell lung cancer (NSCLC). METHODS: Tissue microarrays were prepared from 80 NSCLC specimens and examined by immunohistochemistry. RESULTS: The positive rates of P311 and ITGB4BP expression were 77.5% (62/80) and 82.5% (66/80), respectively. The double positive expression rate was 73.8% (59/80). The consistency rate was 87.5%, and there was a significant consistency between P311 and ITGB4BP expressions (Kappa = 0.611, P < 0.001). CONCLUSION: There may be a new signaling pathway P311-ITGB4BP in NSCLC, and it may regulate the lung cancer cell migration.

SIRT5 Regulates Brown Adipocyte Differentiation and Browning of Subcutaneous White Adipose Tissue.

The unique thermogenic capacity of brown adipocyte makes it an attractive target for antiobesity treatments. Several epigenetic regulators can control brown adipocyte development. In this study, we show that SIRT5, a member of the sirtuins, is required for brown adipocyte differentiation and essential for brown adipogenic gene activation in vitro. Furthermore, we find out that knockdown of SIRT5 reduces intracellular α-ketoglutarate concentration, which leads to elevated H3K9me2 and H3K9me3 levels at promoter regions of Pparγ and Prdm16 loci. Finally, we discover that SIRT5 knockout mice on the Sv129 background exhibit less browning capacity in subcutaneous white adipose tissue compared with controls and show apparent cold intolerance, suggesting that SIRT5 can modulate the browning process in vivo. Thus, our study uncovers a new biological function of SIRT5 in brown adipocyte differentiation and a mechanism by which SIRT5 regulates brown adipogenic gene activation at least partly through an indirect effect on histone modifications. Our study extends the linkage between epigenetics and cell differentiation.

Role of Wnt Inhibitory Factor-1 in Inhibition of Bisdemethoxycurcumin Mediated Epithelial-to-Mesenchymal Transition in Highly Metastatic Lung Cancer 95D Cells.

BACKGROUND: Bisdemethoxycurcumin (BDMC) is an active component of curcumin and a chemotherapeutic agent, which has been suggested to inhibit tumor growth, invasion and metastasis in multiple cancers. But its contribution and mechanism of action in invasion and metastasis of non-small cell lung cancer (NSCLC) are not very clear. Therefore, we tried to study the effects of BDMC on regulation of epithelial-to-mesenchymal transition (EMT), which is closely linked to tumor cell invasion and metastasis. METHODS: In this study, we first induced transforming growth factor-ß1 (TGF-ß1) mediated EMT in highly metastatic lung cancer 95D cells. Thereafter, we studied the effects of BDMC on invasion and migration of 95D cells. In addition, EMT markers expressions were also analyzed by western blot and immunofluorescence assays. The contribution of Wnt inhibitory factor-1 (WIF-1) in regulating BDMC effects on TGF-ß1 induced EMT were further analyzed by its overexpression and small interfering RNA knockdown studies. RESULTS: It was observed that BDMC inhibited the TGF-ß1 induced EMT in 95D cells. Furthermore, it also inhibited the Wnt signaling pathway by upregulating WIF-1 protein expression. In addition, WIF-1 manipulation studies further revealed that WIF-1 is a central molecule mediating BDMC response towards TGF-ß1 induced EMT by regulating cell invasion and migration. CONCLUSIONS: Our study concluded that BDMC effects on TGF-ß1 induced EMT in NSCLC are mediated through WIF-1 and elucidated a novel mechanism of EMT regulation by BDMC.

Design, synthesis, and biological evaluation of novel 2-ethyl-5-phenylthiazole-4-carboxamide derivatives as protein tyrosine phosphatase 1B inhibitors with improved cellular efficacy.

Protein tyrosine phosphatase 1B (PTP1B) is implicated as a key negative regulator of the insulin and leptin signal-transduction pathways. PTP1B inhibitors have emerged as attractive and potent pharmaceutical agents for the treatment of type 2 diabetes and obesity. We identified a series of 2-ethyl-5-phenylthiazole-4-carboxamide (PTA) derivatives, inspired from the ACT scaffold of Scleritodermin A, as a novel class of PTP1B inhibitors. Structure-activity relationship (SAR) analysis and docking studies revealed the molecular basis of PTP1B inhibition by these compounds. PTA derivative 18g was capable of inhibiting intracellular PTP1B and subsequently activating the insulin signaling pathway. Treatment of cells with 18g markedly increased the phosphorylation levels of IRß and Akt as well as the rate of glucose uptake.

Hypomethylation effects of curcumin, demethoxycurcumin and bisdemethoxycurcumin on WIF-1 promoter in non-small cell lung cancer cell lines.

The tumor suppressor gene Wnt inhibitory factor-1 (WIF-1) has been found to be promoter hypermethylated and silenced in lung cancer cell lines and tissues. Curcuminoids are major active components of the spice turmeric, and have recently been reported to be potential hypomethylation agents. In the present study, the hypomethylation effects of three major curcuminoids, curcumin, demethoxycurcumin and bisdemethoxycurcumin, were compared in vitro using ELISA, and their demethylation potential was confirmed by methylation-specific PCR. It was found that bisdemethoxycurcumin possesses the strongest demethylation function in vitro compared to the other two curcuminoids, exerting its effect at a minimal demethylation concentration of 0.5-1 µM. The WIF-1 promoter region was demethylated after treatment with 20 µM demethoxycurcumin and bisdemethoxycurcumin, but failed to respond to 20 µM curcumin. In the A549 cell line, RT-PCR and Western blotting were used to confirm that WIF-1 expression was restored after curcuminoid-induced promoter hypermethylation. Since the results regarding the demethylation potential of the three major curcuminoids to restore WIF-1 expression indicated that bisdemethoxycurcumin has the strongest hypomethylation effect, this curcuminoid may have therapeutic use in the restoration of WIF-1 expression in NSCLC.