A small-molecule activation mechanism that directly opens the KCNQ2 channel.

Pharmacological activation of voltage-gated ion channels by ligands serves as the basis for therapy and mainly involves a classic gating mechanism that augments the native voltage-dependent open probability. Through structure-based virtual screening, we identified a new scaffold compound, Ebio1, serving as a potent and subtype-selective activator for the voltage-gated potassium channel KCNQ2 and featuring a new activation mechanism. Single-channel patch-clamp, cryogenic-electron microscopy and molecular dynamic simulations, along with chemical derivatives, reveal that Ebio1 engages the KCNQ2 activation by generating an extended channel gate with a larger conductance at the saturating voltage (+50 mV). This mechanism is different from the previously observed activation mechanism of ligands on voltage-gated ion channels. Ebio1 caused S6 helices from residues S303 and F305 to perform a twist-to-open movement, which was sufficient to open the KCNQ2 gate. Overall, our findings provide mechanistic insights into the activation of KCNQ2 channel by Ebio1 and lend support for KCNQ-related drug development.

Discovery of a novel GPR35 agonist with high and equipotent species potency for oral treatment of IBD.

The G protein-coupled receptor 35 (GPR35) has been identified as a potential target in the treatment of inflammatory bowel disease (IBD). However, the lack of high and equipotent agonists on both human and mouse GPR35 has limited the in vivo study of GPR35 agonists in mouse models of IBD. In this study, structural modifications to lodoxamide provides a series of high and equivalent agonists on human, mouse, and rat GPR35. These molecules eliminate the species selectivity of human to mouse and rat orthologs that have been prevalent with GPR35 agonists including lodoxamide. The cLogP properties are also optimized to make the compounds more obedient to drug-like rules, yielding compound 4b (cLogP = 2.41), which activates human, mouse or rat GPR35 with EC50 values of 76.0, 63.7 and 77.8 nM, respectively. Oral administration of compound 4b at 20 mg/kg alleviates clinical symptoms of DSS-induced IBD in mice, and is slightly more effective than 5-ASA at 200 mg/kg. In summary, it can serve as a new start point for exploiting more potent GPR35 agonists without species differences for the treatment of IBD, and warrants further study.

Phenotypic screening-based drug discovery of furan-2-carboxylic acid derivatives for the amelioration of type 2 diabetes mellitus (T2DM).

Phenotypic screening still plays an important role in discovering new drugs, especially for diseases with complex pathogenesis, such as diabetes. As excessive gluconeogenesis is considered an important factor in the occurrence of hyperglycemia in T2DM, we previously screened our compounds library for active molecules which inhibit gluconeogenesis, resulting in the discovery of SL010110 with a unique mechanism, different from metformin and a thienopyridine derivative (DMT). The SARs study of SL010110 led to the discovery of 10v. Compared with SL010110, 10v showed improved anti-gluconeogenesis potency and pyruvate tolerance. A further pharmacokinetic study demonstrated that 10v displayed a relatively short half-life, moderate volume of distribution, and moderate to high oral bioavailability. In vivo chronic experiments showed an improved capability of 10v in ameliorating hyperglycemia as the 5 mg/kg 10v treatment greatly reduced non-fasting and fasting blood glucose levels, making it a promising candidate for the treatment of T2DM. The progression from in vitro screening to in vivo testing of the derivatized compounds provided a useful phenotypic screening drug discovery strategy based on the inhibition of gluconeogenesis.

Coronarin A modulated hepatic glycogen synthesis and gluconeogenesis via inhibiting mTORC1/S6K1 signaling and ameliorated glucose homeostasis of diabetic mice.

Promotion of hepatic glycogen synthesis and inhibition of hepatic glucose production are effective strategies for controlling hyperglycemia in type 2 diabetes mellitus (T2DM), but agents with both properties were limited. Herein we report coronarin A, a natural compound isolated from rhizomes of Hedychium gardnerianum, which simultaneously stimulates glycogen synthesis and suppresses gluconeogenesis in rat primary hepatocytes. We showed that coronarin A (3, 10 µM) dose-dependently stimulated glycogen synthesis accompanied by increased Akt and GSK3ß phosphorylation in rat primary hepatocytes. Pretreatment with Akt inhibitor MK-2206 (2 µM) or PI3K inhibitor LY294002 (10 µM) blocked coronarin A-induced glycogen synthesis. Meanwhile, coronarin A (10 µM) significantly suppressed gluconeogenesis accompanied by increased phosphorylation of MEK, ERK1/2, ß-catenin and increased the gene expression of TCF7L2 in rat primary hepatocytes. Pretreatment with ß-catenin inhibitor IWR-1-endo (10 µM) or ERK inhibitor SCH772984 (1 µM) abolished the coronarin A-suppressed gluconeogenesis. More importantly, we revealed that coronarin A activated PI3K/Akt/GSK3ß and ERK/Wnt/ß-catenin signaling via regulation of a key upstream molecule IRS1. Coronarin A (10, 30 µM) decreased the phosphorylation of mTOR and S6K1, the downstream target of mTORC1, which further inhibited the serine phosphorylation of IRS1, and subsequently increased the tyrosine phosphorylation of IRS1. In type 2 diabetic ob/ob mice, chronic administration of coronarin A significantly reduced the non-fasting and fasting blood glucose levels and improved glucose tolerance, accompanied by the inhibited hepatic mTOR/S6K1 signaling and activated IRS1 along with enhanced PI3K/Akt/GSK3ß and ERK/Wnt/ß-catenin pathways. These results demonstrate the anti-hyperglycemic effect of coronarin A with a novel mechanism by inhibiting mTORC1/S6K1 to increase IRS1 activity, and highlighted coronarin A as a valuable lead compound for the treatment of T2DM.

General Pharmacological Activation Mechanism of K+ Channels Bypassing Channel Gates.

Under the known pharmacological activation mechanisms, activators allosterically or directly open potassium channel gates. However, herein, molecular dynamics simulations on TREK-1, a member of the channel class gated at the filter, suggested that negatively charged activators act with a gate-independent mechanism where compounds increase currents by promoting ions passing through the central cavity. Then, based on studies of KCNQ2, we uncovered that this noncanonical activation mechanism is shared by the other channel class gated at the helix-bundle crossing. Rational drug design found a novel KCNQ2 agonist, CLE030, which stably binds to the central cavity. Functional analysis, molecular dynamics simulations, and calculations of the potential of mean force revealed that the carbonyl oxygen of CLE030 influences permeant ions in the central cavity to contribute to its activation effects. Together, this study discovered a ligand-to-ion activation mechanism for channels that bypasses their gates and thus is conserved across subfamilies with different gates.

Discovery of novel ketoxime ether derivatives with potent FXR agonistic activity, oral effectiveness and high liver/blood ratio.

The farnesoid X receptor (FXR) is a promising therapeutic target for nonalcoholic steatohepatitis (NASH) and other bile acid related diseases because it plays a critical role in fibrosis, inflammation and bile acid homeostasis. Obeticholic acid (OCA), a FXR agonist which was synthesized from chenodeoxycholic acid, showed desirable curative effects in clinical trials. However, the pruritus which was the main side effect of OCA limited its further applications in NASH. Although pruritus was also observed in the clinical trials of non-steroidal FXR agonists, the proportion of patients with pruritus was much smaller than that of OCA. Thus, we decided to develop non-steroidal FXR agonists and discovered a series of novel FXR agonists which were synthesized from GW4064 by replacing the stilbene group with ketoxime ether. Encouragingly, in the following biological tests, our target compounds 13j and 13z not only showed potent FXR agonistic activities in vitro, but also effectively promoted the expression of target genes in vivo. More importantly, in the pharmacokinetic experiments, compounds 13j and 13z displayed high liver/blood ratio characteristics which were helpful to reduce the potential side effects which were caused by prolonged systemic activation of FXR. In summary, our compounds were good choices for the development of non-steroidal FXR agonists and were deserved further investigation.

SL010110, a lead compound, inhibits gluconeogenesis via SIRT2-p300-mediated PEPCK1 degradation and improves glucose homeostasis in diabetic mice.

Suppression of excessive hepatic gluconeogenesis is an effective strategy for controlling hyperglycemia in type 2 diabetes (T2D). In the present study, we screened our compounds library to discover the active molecules inhibiting gluconeogenesis in primary mouse hepatocytes. We found that SL010110 (5-((4-allyl-2-methoxyphenoxy) methyl) furan-2-carboxylic acid) potently inhibited gluconeogenesis with 3 µM and 10 µM leading to a reduction of 45.5% and 67.5%, respectively. Moreover, SL010110 caused suppression of gluconeogenesis resulted from downregulating the protein level of phosphoenolpyruvate carboxykinase 1 (PEPCK1), but not from affecting the gene expressions of PEPCK, glucose-6-phosphatase, and fructose-1,6-bisphosphatase. Furthermore, SL010110 increased PEPCK1 acetylation, and promoted PEPCK1 ubiquitination and degradation. SL010110 activated p300 acetyltransferase activity in primary mouse hepatocytes. The enhanced PEPCK1 acetylation and suppressed gluconeogenesis caused by SL010110 were blocked by C646, a histone acetyltransferase p300 inhibitor, suggested that SL010110 inhibited gluconeogenesis by activating p300. SL010110 decreased NAD+/NADH ratio, inhibited SIRT2 activity, and further promoted p300 acetyltransferase activation and PEPCK1 acetylation. These effects were blocked by NMN, an NAD+ precursor, suggested that SL010110 inhibited gluconeogenesis by inhibiting SIRT2, activating p300, and subsequently promoting PEPCK1 acetylation. In type 2 diabetic ob/ob mice, single oral dose of SL010110 (100 mg/kg) suppressed gluconeogenesis accompanied by the suppressed hepatic SIRT2 activity, increased p300 activity, enhanced PEPCK1 acetylation and degradation. Chronic oral administration of SL010110 (15 or 50 mg/kg) significantly reduced the blood glucose levels in ob/ob and db/db mice. This study reveals that SL010110 is a lead compound with a distinct mechanism of suppressing gluconeogenesis via SIRT2-p300-mediated PEPCK1 degradation and potent anti-hyperglycemic activity for the treatment of T2D.

Design of G-protein-coupled bile acid receptor 1 (GPBAR1, TGR5) soft drugs with reduced gallbladder-filling effects.

The G-protein-coupled bile acid receptor TGR5 agonists were widely developed in type 2 diabetes and gastrointestinal disorders, but were also full of challenges, due to the systemic on-targeted side effects, especially the gallbladder-filling effects. Here, to circumvent these risks, several TGR5 agonists with soft-drug designation had been designed and synthesized with the properties of rapid metabolized after drug effect. Among them, compound 19 showed negligible systemic exposure and favorable gallbladder safety on a 3-day continuous administration, providing a novel strategy for developing TGR5 agonists.

TGR5 agonist ameliorates insulin resistance in the skeletal muscles and improves glucose homeostasis in diabetic mice.

BACKGROUND AND PURPOSE: TGR5 plays an important role in many physiological processes. However, the functions of TGR5 in the regulation of the glucose metabolism and insulin sensitivity in the skeletal muscles have not been fully elucidated. We synthesized MN6 as a potent and selective TGR5 agonist. Here, the effect of MN6 on insulin resistance in skeletal muscles was evaluated in diet-induced obese (DIO) mice and C2C12 myotubes, and the underlying mechanisms were explored. METHODS: The activation of MN6 on human and mouse TGR5 was evaluated by a cAMP assay in HEK293 cell lines stable expressing hTGR5/CRE or mTGR5/CRE cells. GLP-1 secretion was measured in NCI-H716 cells and CD1 mice. The acute and chronic effects of MN6 on regulating metabolic abnormalities were observed in ob/ob and DIO mice. 2-deoxyglucose uptake was examined in isolated skeletal muscles. Akt phosphorylation, glucose uptake and glycogen synthesis were examined to assess the effects of MN6 on palmitate-induced insulin resistance in C2C12 myotubes. RESULTS: MN6 potently activated human and mouse TGR5 with EC50 values of 15.9 and 17.9 nmol/L, respectively, and stimulated GLP-1 secretion in NCI-H716 cells and CD1 mice. A single oral dose of MN6 significantly decreased the blood glucose levels in ob/ob mice. Treatment with MN6 for 15 days reduced the fasting blood glucose and HbA1c levels in ob/ob mice. MN6 improved glucose and insulin tolerance and enhanced the insulin-stimulated glucose uptake of skeletal muscles in DIO mice. The palmitate-induced impairment of insulin-stimulated Akt phosphorylation, glucose uptake and glycogen synthesis in C2C12 myotubes could be prevented by MN6. The effect of MN6 on palmitate-impaired insulin-stimulated Akt phosphorylation was abolished by siRNA-mediated knockdown of TGR5 or by the inhibition of adenylate cyclase or protein kinase A, suggesting that this effect is dependent on the activation of TGR5 and the cAMP/PKA pathway. CONCLUSIONS: Our study identified that a TGR5 agonist could ameliorate insulin resistance by the cAMP/PKA pathway in skeletal muscles; this uncovered a new effect of the TGR5 agonist on regulating the glucose metabolism and insulin sensitivity in skeletal muscles and further strengthened its potential value for the treatment of type 2 diabetes.

Linderane Suppresses Hepatic Gluconeogenesis by Inhibiting the cAMP/PKA/CREB Pathway Through Indirect Activation of PDE 3 via ERK/STAT3.

The role of phosphodiesterase 3 (PDE3), a cyclic AMP (cAMP)-degrading enzyme, in modulating gluconeogenesis remains unknown. Here, linderane, a natural compound, was found to inhibit gluconeogenesis by activating hepatic PDE3 in rat primary hepatocytes. The underlying molecular mechanism and its effects on whole-body glucose and lipid metabolism were investigated. The effect of linderane on gluconeogenesis, cAMP content, phosphorylation of cAMP-response element-binding protein (CREB) and PDE activity were examined in cultured primary hepatocytes and C57BL/6J mice. The precise mechanism by which linderane activates PDE3 and inhibits the cAMP pathway was explored using pharmacological inhibitors. The amelioration of metabolic disorders was observed in ob/ob mice. Linderane inhibited gluconeogenesis, reduced phosphoenolpyruvate carboxykinase (Pck1) and glucose-6-phosphatase (G6pc) gene expression, and decreased intracellular cAMP concentration and CREB phosphorylation in rat primary hepatocytes under both basal and forskolin-stimulated conditions. In rat primary hepatocytes, it also increased total PDE and PDE3 activity but not PDE4 activity. The suppressive effect of linderane on the cAMP pathway and gluconeogenesis was abolished by the non-specific PDE inhibitor 3-isobutyl-1-methylxanthine (IBMX) and the specific PDE3 inhibitor cilostazol. Linderane indirectly activated PDE3 through extracellular regulated protein kinase 1/2 (ERK1/2) and signal transducer and activator of transcription 3 (STAT3) activation. Linderane improved glucose and lipid metabolism after chronic oral administration in ob/ob mice. Our findings revealed linderane as an indirect PDE3 activator that suppresses gluconeogenesis through cAMP pathway inhibition and has beneficial effects on metabolic syndromes in ob/ob mice. This investigation highlighted the potential for PDE3 activation in the treatment of type 2 diabetes.

Design, synthesis and structure-activity relationship studies of GPR40 agonists containing amide linker.

Free fatty acid receptor 1 (FFAR1/GPR40) attracted significant attention as a potential target for developing novel antidiabetic drugs because of its unique mechanism in glucose homeostasis. Several reports have expressed concerns about central nervous system (CNS) penetration of GPR40 agonists, which is possibly attributed to their high lipophilicity and low total polar surface area. Herein, we report our efforts to improve the physicochemical properties and pharmacokinetic profiles of LY2881835, a GPR40 agonist that had undergone Phase I clinical trial, through a series of structural optimizations. We identified an orally efficacious compound, 15k, which possessed increased plasma exposure, prolonged half-life and reduced CNS exposure and liver to plasma distribution ratio compared with LY2881835. 15k is a potentially valuable lead compound in the development of safe and efficacious GPR40-targeted drugs to treat type 2 diabetes mellitus.

Orally Administrated Small Molecule Drugs with Intestine Targeted Profile: Recent Development and Prospects.

BACKGROUND: Intestine targeted drugs are orally administered compounds exerting their therapeutic effects locally in the intestinal tract, thus avoiding side effects related to systemic exposure. OBJECTIVE: Both academic and pharmaceutical research has, therefore, focused on such agents, but the systematic methodology needed for their design and evaluation has been unclear. Thus, careful summary of this kind of drugs is vital for drug design. METHOD: This review summarizes achievements from 2013 to 2016, through literatures, patents and related websites, in developing orally administrated small molecule drugs with intestine targeted profile. RESULTS: This review summarized six categories of intestine targeted drugs, based on various design strategies, with careful analysis of recent examples from each category. CONCLUSION: Our analysis indicated that the intestine targeted profile could expand the therapeutic window of drugs while retaining their efficacy. Thus, we describe simple approaches suitable for rational design of intestine targeted drugs.

Intestinally-targeted TGR5 agonists equipped with quaternary ammonium have an improved hypoglycemic effect and reduced gallbladder filling effect.

TGR5 activation of enteroendocrine cells increases glucagon-like peptide 1 (GLP-1) release, which maintains glycemic homeostasis. However, TGR5 activation in the gallbladder and heart is associated with severe side effects. Therefore, intestinally-targeted TGR5 agonists were suggested as potential hypoglycemic agents with minimal side effects. However, until now no such compounds with robust glucose-lowering effects were reported, especially in diabetic animal models. Herein, we identify a TGR5 agonist, 26a, which was proven to be intestinally-targeted through pharmacokinetic studies. 26a was used as a tool drug to verify the intestinally-targeted strategy. 26a displayed a robust and long-lasting hypoglycemic effect in ob/ob mice (once a day dosing (QD) and 18-day treatment) owing to sustained stimulation of GLP-1 secretion, which suggested that robust hypoglycemic effect could be achieved with activation of TGR5 in intestine alone. However, the gallbladder filling effect of 26a was rather complicated. Although the gallbladder filling effect of 26a was decreased in mice after once a day dosing, this side effect was still not eliminated. To solve the problem above, several research strategies were raised for further optimization.

OL3, a novel low-absorbed TGR5 agonist with reduced side effects, lowered blood glucose via dual actions on TGR5 activation and DPP-4 inhibition.

AIM: TGR5 agonists stimulate intestinal glucagon-like peptide-1 (GLP-1) release, but systemic exposure causes unwanted side effects, such as gallbladder filling. In the present study, linagliptin, a DPP-4 inhibitor with a large molecular weight and polarity, and MN6, a previously described TGR5 agonist, were linked to produce OL3, a novel low-absorbed TGR5 agonist with reduced side-effects and dual function in lowering blood glucose by activation of TGR5 and inhibition of DPP-4. METHODS: TGR5 activation was assayed in HEK293 cells stably expressing human or mouse TGR5 and a CRE-driven luciferase gene. DPP-4 inhibition was assessed based on the rate of hydrolysis of a surrogate substrate. GLP-1 secretion was measured in human enteroendocrine NCI-H716 cells. OL3 permeability was tested in Caco-2 cells. Acute glucose-lowering effects of OL3 were evaluated in ICR and diabetic ob/ob mice. RESULTS: OL3 activated human and mouse TGR5 with an EC50 of 86.24 and 17.36 nmol/L, respectively, and stimulated GLP-1 secretion in human enteroendocrine NCI-H716 cells (3-30 µmol/L). OL3 inhibited human and mouse DPP-4 with IC50 values of 18.44 and 69.98 µmol/L, respectively. Low permeability of OL3 was observed in Caco-2 cells. In ICR mice treated orally with OL3 (150 mg/kg), the serum OL3 concentration was 101.10 ng/mL at 1 h, and decreased to 13.38 ng/mL at 5.5 h post dose, confirming the low absorption of OL3 in vivo. In ICR mice and ob/ob mice, oral administration of OL3 significantly lowered the blood glucose levels, which was a synergic effect of activating TGR5 that stimulated GLP-1 secretion in the intestine and inhibiting DPP-4 that cleaved GLP-1 in the plasma. In ICR mice, oral administration of OL3 did not cause gallbladder filling. CONCLUSION: OL3 is a low-absorbed TGR5 agonist that lowers blood glucose without inducing gallbladder filling. This study presents a new strategy in the development of potent TGR5 agonists in treating type 2 diabetes, which target to the intestine to avoid systemic side effects.

Discovery and Structure-Activity Relationship Study of 4-Phenoxythiazol-5-carboxamides as Highly Potent TGR5 Agonists.

A novel therapy that stimulates endogenous glucagon-like peptide-1 (GLP-1) secretion by Takeda G-protein-coupled receptor 5 (TGR5) agonists might be a superior alternative for the treatment of type 2 diabetes mellitus. A series of 4-phenoxythiazol-5-carboxamides were developed as highly potent TGR5 agonists using a bioisosteric replacement strategy based on the scaffold of 4-phenoxynicotinamides. The structure-activity relationship on the bottom phenyl ring and the thiazole ring was extensively studied, and the 2-methyl-thiazole derivatives 30c and e displayed the best in vitro potency toward human TGR5, with EC50 values of approximately 1 nM. While endowed with excellent in vitro potency, the 2-methyl-thiazoles were flawed with high microsomal clearance.

Discovery of Intestinal Targeted TGR5 Agonists for the Treatment of Type 2 Diabetes.

Activation of TGR5 stimulates intestinal glucagon-like peptide-1 (GLP-1) release, but activation of the receptors in gallbladder and heart has been shown to cause severe on-target side effects. A series of low-absorbed TGR5 agonists was prepared by modifying compound 2 with polar functional groups to limit systemic exposure and specifically activate TGR5 in the intestine. Compound 15c, with a molecular weight of 1401, a PSA value of 223 Å(2), and low permeability on Caco-2 cells, exhibited satisfactory potency both in vitro and in vivo. Low levels of 15c were detected in blood, bile, and gallbladder tissue, and gallbladder-related side effects were substantially decreased compared to the absorbed small-molecule TGR5 agonist 2.

Design, synthesis, and structure-activity relationships of 3,4,5-trisubstituted 4,5-dihydro-1,2,4-oxadiazoles as TGR5 agonists.

Given its role in the mediation of energy and glucose homeostasis, the G-protein-coupled bile acid receptor 1 (TGR5) is considered a potential target for the treatment of type 2 diabetes mellitus and other metabolic disorders. By thorough analysis of diverse structures of published TGR5 agonists, a hypothetical ligand-based pharmacophore model was built, and a new class of potent TGR5 agonists, based on the novel 3,4,5-trisubstituted 4,5-dihydro-1,2,4-oxadiazole core, was discovered by rational design. Three distinct synthetic methods for constructing 4,5-dihydro-1,2,4-oxadiazoles and extensive structure-activity relationship studies are reported herein. Compound (R)-54 n, the structure of which was determined by single-crystal X-ray diffraction and quantum chemical solid-state TDDFT-ECD calculations, showed the best potency, with an EC50 value of 1.4 nM toward hTGR5. Its favorable properties in vitro warrant further investigation.

Pyrimidinyl-arylpropionic acid derivatives: viable resources in the development of new antineoplastic agents.

Numerous studies have documented that various naturally derived ligands or synthetic non-thiazolidinediones (TZD) as peroxisome proliferator-activated receptor gamma (PPARgamma) agonists have shown moderate or potent antitumor activities, which is PPARgamma independent or partially dependent. However, the PPARgamma agonistic or glucose-lowering activity is ranked first more often than antitumor activity to determine promising novel PPARgamma agonists for potential clinical use. In this study, we hypothesized that there might exist some compounds with less PPARgamma agonistic activity but potent antitumor activity. Thereafter, we evaluated the PPARgamma agonistic and antitumor activity of a novel series of alpha-aryloxy-alpha-methylhydrocinnamic acid derivatives synthesized with the initial aim of developing novel PPARgamma agonists as hypoglycemic agents. MTT assay results revealed that several compounds were able to inhibit cell proliferation in a dose-dependent manner with IC(50) 12.7-29.7 microM, better than that of rosiglitazone (45.9-141 microM), although the PPARgamma agonistic activity of most compounds is much lower than rosiglitazone. Some compounds induced cell cycle arrest and apoptosis tested by Flow Cytometry. Oral administration of DH9 (100 mg/kg/d) for 21 days to BALB/c nude mice bearing xenografts including MGC-803, NCI-H460, HT-29 and OS-RC-2 cells significantly retarded tumor growth. DG8 and DJ5 showed benefits in some of the above four xenografts. Our findings demonstrate that these compounds have potent antitumor activity in vitro and in vivo and pyrimidinyl-arylpropionic acid derivatives might be viable resources in the development of new antineoplastic agents.

Antitumor efficacy of two novel non-thiazolidinedione compounds as peroxisome proliferator-activated receptor-gamma agonists in human osteosarcoma cells in vitro.

BACKGROUND: Due to chemotherapy resistance in osteosarcoma subgroups, the prognosis of these patients is still poor, and the development of new agents is of utmost importance. The aim of our study was to test the antitumor effects of two novel alpha-aryloxy-alpha-methylhydrocinnamic acid derivatives as peroxisome proliferator-activated receptor (PPAR) gamma agonists, together with rosiglitazone, a well-known thiazolidinedione (TZD) acting on several osteosarcoma cell lines. METHODS/RESULTS: The MTT assay revealed that cell viability was inhibited in a dose-dependent manner with IC(50) 6.2-15.8 microM for the two novel compounds and rosiglitazone (48.4-83.5 microM). Exposure to DG8 and DH9 at low micromolar concentrations induced a dose-dependent block of DNA synthesis and colony formation. In these antitumor assays, DG8 and DH9 were more effective than rosiglitazone, although the PPARgamma agonistic activity of rosiglitazone is much higher. The SiRNA approach to downregulate specifically PPARgamma in U-2OS cells did not affect the cytotoxic efficiency of either the two novel compounds or rosiglitazone. CONCLUSION: These observations suggest that non-TZDs with less PPARgamma agonistic activity might show more potent antitumor efficacy independent of PPARgamma in human osteosarcoma cells, which supports the possibility that they could be beneficial in the treatment of osteosarcoma patients.

Discovery of novel dual functional agent as PPARgamma agonist and 11beta-HSD1 inhibitor for the treatment of diabetes.

PPARgamma and 11beta-HSD1 are attractive therapeutic targets for type 2 diabetes. However, PPARgamma agonists induce adipogenesis, which causes the side effect of weight gain, whereas 11beta-HSD1 inhibitors prevent adipogenesis and may be beneficial for the treatment of obesity in diabetic patients. For the first time, we designed, synthesized a series of alpha-aryloxy-alpha-methylhydrocinnamic acids as dual functional agents which activate PPARgamma and inhibit 11beta-HSD1 simultaneously. The compound 11e exhibited the most potent inhibitory activity compared to that of the lead compound 2, with PPARgamma (EC(50)=6.76 microM) and 11beta-HSD1 (IC(50)=0.76 microM) in vitro. Molecular modeling study for compound 11e was also presented. Compound 11e showed excellent efficacy for lowering glucose, triglycerides, body fat, in well established mice and rats models of diabetes and obesity and had a favorable ADME profile.