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The active components of Malus pumila flowers on antioxidant and tyrosinase activity were investigated with the method of spectrum-effect relationship and knock-out. Some compounds were identified by UPLC-MS/MS method. The chemical fingerprints were established by HPLC and the activity of antioxidant and tyrosinase were assayed in vitro. Chromatographic peaks P34, P35, P39, P44, P45 and P49 were identified as phloridzin, hyperoside, astragalin, afzelin, quercetin and kaempferol by UPLC-MS/MS method. Hyperoside and kaempferol were identified in M. pumila flowers for the first time. When the concentration was 1 g/mL of sample (equivalent to raw material), the scavenging capacity of P35 (hyperoside) on DPPH free radicals were consistent with the spectrum-effect relationship. The scavenging capacity of P34 (phloridzin) and P45 (quercetin) on ABTS free radicals were consistent with the spectrum-effect relationship. The activation effect of P45 (quercetin) on tyrosinase was consistent with the spectrum-effect relationship. The inhibitory effect of P34 (phloridzin), P35 (hyperoside) on tyrosinase were consistent with the spectrum-effect relationship., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Type 2 diabetes mellitus is a complex metabolic disorder requiring polypharmacology approaches for effective treatment. Combinatorial library of fifteen new tricyclic benzimidazole derivatives have been designed and synthesized to combine fragments commonly found in allosteric AMPK activators and AT 1 receptor antagonists. It was found that 2'-cyanobiphenyl serves as the pharmacophore of AMPK-activating activity, which also increases with the expansion of the external hydrogenated cycle. Also, pronounced antiplatelet activity is characteristic of the studied compounds. One of derivatives was identified as a potent inhibitor of the formation of advanced protein glycation end-products with reactive dicarbonyl scavenging activity. Two submicromolar AMPK activators 2b and 3b prevents inflammatory activation of murine macrophages. Along with good water solubility and synthetic availability, these results render biphenyl derivatives of fused benzimidazoles as a valuable starting point for the development of AMPK activators with multi-target antidiabetic activity., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Protein-polymer conjugation is a clinically validated approach to enhanced pharmacokinetic properties. However, the permanent attachment of polymers often leads to irreversibly reduced protein bioactivity and poor tissue penetration. As such, the use of protein-polymer conjugates for solid tumors remains elusive. Herein, we report a simple strategy using enzyme-activatable and size-shrinkable protein-polypeptide conjugates to overcome this clinical challenge. Briefly, a matrix metalloproteinase (MMP)-responsive peptide sequence is introduced between a therapeutic protein interferon (IFN) and a synthetic polypeptide P(EG 3 Glu) 20 . The resulting site-specific MMP-responsive conjugate, denoted as PEP 20 -M-IFN, can, therefore, release the attached P(EG 3 Glu) 20 to achieve both protein activation and deep penetration into the tumor microenvironment (TME). Compared to a similarly produced nonresponsive analogue conjugate PEP 20 -IFN, our results find PEP 20 -M-IFN to show higher bioactivity in vitro, improved tumor retention, and deeper penetration in a MMP2-dependent manner. Moreover, systemic administration of PEP 20 -M-IFN shows outstanding antitumor efficacy in both OVCAR3 and SKOV3 ovarian tumor models in mice. This work highlights the releasable PEPylation strategy for protein drug potentiation at the TME and opens up new opportunities in clinics for the treatment of malignant solid tumors.

We have designed novel tropinone-thiazole derivatives that showed high antiproliferative activity against a variety of cancer cell lines via caspase 3/7 activation mechanism. Among the derivatives, compounds 3b-3h were found to exhibit high activity against human leukemia (MV4-11), human lung carcinoma (A549), human breast carcinoma (MCF-7), and skin melanoma (B16-F10) cancer cell lines, with IC 50 values of 5.43-11.06 μM. The lead compound 3g increases caspase 3/7 activity in A549 cells 25 times more than the control, and 2 times more than reference drug camptothecin. We have also found that tropinone-thiazole derivatives exhibit high tyrosinase inhibitory activity. The lead compounds 3g and 3h showed tyrosinase inhibition effect, with IC 50 values 3.22 and 3.51 μM, respectively. These inhibitory activities are 22 times higher than the activity of kojic acid (IC 50 72.27 μM) and 120 times higher than activity of ascorbic acid (IC 50 386.5 μM). For compounds 3g and 3h, the experimentally determined lipophilicity correlates very well with their enzymatic activities. These data suggest that presented compounds could constitute lead anticancer drug candidates., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Proteasomes are multienzyme complexes that maintain protein homeostasis (proteostasis) and important cellular functions through the degradation of misfolded, redundant, and damaged proteins. It is well established that aging is associated with the accumulation of damaged and misfolded proteins. This phenomenon is paralleled by declined proteasome activity. When the accumulation of redundant proteins exceed degradation, undesirable signaling and/or aggregation occurs and are the hallmarks of neurodegenerative diseases and many cancers. Thus, increasing proteasome activity has been recognized as a new approach to delay the onset or ameliorate the symptoms of neurodegenerative and other proteotoxic disorders. Enhancement of proteasome activity has many therapeutic potentials but is still a relatively unexplored field. In this perspective, we review current approaches, genetic manipulation, posttranslational modification, and small molecule proteasome agonists used to increase proteasome activity, challenges facing the field, and applications beyond aging and neurodegenerative diseases.

Pharmacological strategies that boost intracellular NAD + are highly coveted for their therapeutic potential. One approach is activation of nicotinamide phosphoribosyltransferase (NAMPT) to increase production of nicotinamide mononucleotide (NMN), the predominant NAD + precursor in mammalian cells. A high-throughput screen for NAMPT activators and hit-to-lead campaign yielded SBI-797812, a compound that is structurally similar to active-site directed NAMPT inhibitors and blocks binding of these inhibitors to NAMPT. SBI-797812 shifts the NAMPT reaction equilibrium towards NMN formation, increases NAMPT affinity for ATP, stabilizes phosphorylated NAMPT at His247, promotes consumption of the pyrophosphate by-product, and blunts feedback inhibition by NAD + . These effects of SBI-797812 turn NAMPT into a "super catalyst" that more efficiently generates NMN. Treatment of cultured cells with SBI-797812 increases intracellular NMN and NAD + . Dosing of mice with SBI-797812 elevates liver NAD + . Small molecule NAMPT activators such as SBI-797812 are a pioneering approach to raise intracellular NAD + and realize its associated salutary effects.

Deazaflavin-dependent nitroreductase (Ddn) is an emerging target in the field of anti-tuberculosis agents. In the present study, 2-nitroimidazooxazine derivatives as Ddn activators were aligned for CoMFA, CoMSIA and HQSAR analysis. The best CoMFA and CoMSIA model were generated with leave-one-out correlation coefficients (q 2 ) of 0.585 and 0.571, respectively. Both the CoMFA and CoMSIA models were also validated by a test set of 11 compounds with satisfactory [Formula: see text] value of 0.701 and 0.667, respectively. Results of 3D QSAR and HQSAR study were used for the designing of novel and potent nitroimidazooxazine derivatives as Ddn activators. 21 novel compounds were designed, and docked into the Ddn enzyme. In docking study compound ng11 showed interaction with key amino acid residues such as Tyr65 and Tyr133, and also showed better ADMET compatibility. The ADMET prediction, docking study and the predicted activity of novel designed compounds revealed that compound ng11 showed good potential as Ddn activators for the treatment of tuberculosis.

A novel strategy for enhancing the activity and stability of metal-activated enzymes by allosteric control and confinement of metal-nulceobase hybrid coordination was reported in this study. Despite the lack of active Mg2+ ions, methionine adenosyltransferase (MAT) immobilized by Zn2(adenine) still exhibited robust catalytic activity and stability at pH 3 and 80 °C.

Multiple lines of evidence have indicated that pyruvate kinase M2 (PKM2) is upregulated in most cancer cells and it is increasingly recognized as a potential therapeutic target in oncology. In a continuation of our discovery of lead compound 5 and SAR study, the 7-azaindole moiety in compound 5 was systematically optimized. The results showed that compound 6f, which has a difluoroethyl substitution on the 7-azaindole ring, exhibited high PKM2 activation potency and anti-proliferation activities on A375 cell lines. In a xenograft mouse model, oral administration of compound 6f led to significant tumor regression without obvious toxicity. Further mechanistic studies revealed that 6f could influence the translocation of PKM2 into nucleus, as well as induction of apoptosis and autophagy of A375 cells. More importantly, compound 6f significantly inhibited migration of A375 cells in a concentration-dependent manner. Collectively, 6f may serve as a lead compound in the development of potent PKM2 activators for cancer therapy., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

In the present study, several decursin analogues (KC1-3) were synthesized and evaluated in terms of their anti-septic activities on high mobility group box 1 (HMGB1)-mediated septic responses and survival rate in a mouse model of sepsis. KC1 and KC3, but not KC2, significantly reduced HMGB1 release in lipopolysaccharide (LPS)-activated human umbilical vein endothelial cells (HUVECs) and attenuated the cecal ligation and puncture (CLP)-induced release of HMGB1. Additionally, in vitro analyses revealed that KC1 and KC3 both alleviated HMGB1-mediated vascular disruptions and inhibited hyperpermeability in mice, and in vivo analyses revealed that KC1 and KC3 reduced sepsis-related mortality and tissue injury. Taken together, the present results suggest that KC1 and KC3 both reduced HMGB1 release and septic mortality and, thus, may be useful for the treatment of sepsis., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The soluble guanylyl cyclase (sGC) plays a key role in NO/cGMP signalling and is widely recognised to be important in different disease pathomechanisms. The discovery of sGC agonists provides a new opportunity to stimulate the NO/cGMP pathway. One class of compounds are the heme-independent sGC activators, which are thought to bind to oxidised or heme-free sGC. This enzyme is preferentially formed under disease situations accompanied by oxidative stress. Accordingly, this binding mode of sGC activators has quite some appeal for the clinical use of sGC activator drugs in diseases with high oxidative stress burden. However, none of the previous sGC activators, most of them dicarboxylic acid derivatives, has passed clinical trials to date, also because of the potent blood pressure lowering effects. In the current study, we investigate the effects of a new monocarboxylic drug BR 11257 in vitro and in vivo. Activity measurements with purified enzyme indicated gentle sGC activation for BR 11257 resembling a partial agonistic behaviour. In thermal shift measurements, we observed an unexpected difference between BR 11257 and the sGC activators from the dicarboxylic acid type. While activators from the dicarboxylic acid type had a highly thermostabilising influence on sGC, this effect was absent with BR 11257. We hypothesize that the key interaction partner for thermostabilisation is the second carboxylic acid in BAY 60-2770 which is missing in BR 11257. The absence of this thermodynamic receptor stabilisation and the partial agonism may be advantageous to overcome limitations of this class of drugs by avoiding excessive hypotension., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Protein kinase A (PKA), the main effector of cAMP in eukaryotes, is a paradigm for the mechanisms of ligand-dependent and allosteric regulation in signalling. Here we report the orthologous but cAMP-independent PKA of the protozoan Trypanosoma and identify 7-deaza-nucleosides as potent activators (EC 50  ≥ 6.5 nM) and high affinity ligands (K D  ≥ 8 nM). A co-crystal structure of trypanosome PKA with 7-cyano-7-deazainosine and molecular docking show how substitution of key amino acids in both CNB domains of the regulatory subunit and its unique C-terminal αD helix account for this ligand swap between trypanosome PKA and canonical cAMP-dependent PKAs. We propose nucleoside-related endogenous activators of Trypanosoma brucei PKA (TbPKA). The existence of eukaryotic CNB domains not associated with binding of cyclic nucleotides suggests that orphan CNB domains in other eukaryotes may bind undiscovered signalling molecules. Phosphoproteome analysis validates 7-cyano-7-deazainosine as powerful cell-permeable inducer to explore cAMP-independent PKA signalling in medically important neglected pathogens.

A series of 4-substituted-spinaceamine (4,5,6,7-tetrahydro-imidazolo[4,5-c]pyridine) were prepared from histamine and aromatic aldehydes Schiff bases, and investigated as activators of four human (h) carbonic anhydrase (CA, EC 4.2.1.1) isoforms, the cytosolic hCA I, II and VII, and the membrane-associated hCA IV. All isoforms were effectively activated by the new derivatives, and the nature of the moiety in position 4 of the bicyclic system was the factor influencing activation properties against all isoforms. For hCA I, these compounds showed K A s in the range of 2.52-21.5 µM, the most effective activator being 4-(2-hydroxyphenyl)-spinaceamine. For hCA II the activation constants ranged between 0.60 and 17.2 µM, with 4-(2,3,5,6-tetrafluorophenyl)- spinaceamine the best activator. Affinity for hCA IV was in the range of 0.52-63.8 µM, and the same compound as for hCA II was the most effective activator. The most sensitive isoform for activation was the brain-associated hCA VII, for which K A s in the range of 82 nM-4.26 µM were observed. Effective hCA VII activators were the (2-bromophenyl)-, 2,3,5,6-tetrafluorophenyl- and furyl-substituted spineaceamines (K A s of 82-95 nM). As CA activators may have pharmacologic applications in various fields, this work provides interesting derivatives for further studies., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Gaucher's disease is a lysosomal disease caused by mutations in the β-glucocerebrosidase gene ( GBA1 and GCase) that have been also linked to increased risk of Parkinson's disease (PD) and Diffuse Lewy body dementia. Prior studies have suggested that mutant GCase protein undergoes misfolding and degradation, and therefore, stabilization of the mutant protein represents an important therapeutic strategy in synucleinopathies. In this work, we present a structure-activity relationship (SAR) study of quinazoline compounds that serve as inhibitors of GCase. Unexpectedly, we found that N-methylation of these inhibitors transformed them into GCase activators. A systematic SAR study further revealed that replacement of the key oxygen atom in the linker of the quinazoline derivative also contributed to the activity switch. PD patient-derived fibroblasts and dopaminergic midbrain neurons were treated with a selected compound (9q) that partially stabilized GCase and improved its activity. These results highlight a novel strategy for therapeutic development of noninhibitory GCase modulators in PD and related synucleinopathies.

Phytoecdysteroids exert their non-hormonal anabolic and adaptogenic effects in mammals, including humans, through a partially revealed mechanism of action involving the activation of protein kinase B (Akt). We have recently found that poststerone, a side-chain cleaved in vivo metabolite of 20-hydroxyecdysone, exerts potent anabolic activity in rats. Here we report the semi-synthetic preparation of a series of side-chain cleaved ecdysteroids and their activity on the Akt phosphorylation in murine skeletal muscle cells. Twelve C-21 ecdysteroids including 8 new compounds were obtained through the oxidative side-chain cleavage of various phytoecdysteroids, or through the base-catalyzed autoxidation of poststerone. The complete 1 H and 13 C NMR spectroscopic assignments of the new compounds are presented. Among the tested compounds, 9 could activate Akt stronger than poststerone revealing that side-chain cleaved derivatives of phytoecdysteroids other than 20-hydroxyecdysone are valuable bioactive metabolites. Thus, our results suggest that the expectable in vivo formation of such compounds should contribute to the bioactivity of herbal preparations containing ecdysteroid mixtures., (Copyright © 2018 Elsevier Inc. All rights reserved.)

AMP-activated protein kinase (AMPK) is an attractive therapeutic target for managing metabolic diseases. A class of pharmacological activators, including Merck 991, binds the AMPK ADaM site, which forms the interaction surface between the kinase domain (KD) of the α-subunit and the carbohydrate-binding module (CBM) of the β-subunit. Here, we report the development of two new 991-derivative compounds, R734 and R739, which potently activate AMPK in a variety of cell types, including β 2 -specific skeletal muscle cells. Surprisingly, we found that they have only minor effects on direct kinase activity of the recombinant α 1 β 2 γ 1 isoform yet robustly enhance protection against activation loop dephosphorylation. This mode of activation is reminiscent of that of ADP, which activates AMPK by binding to the nucleotide-binding sites in the γ-subunit, more than 60 Å away from the ADaM site. To understand the mechanisms of full and partial AMPK activation, we determined the crystal structures of fully active phosphorylated AMPK α 1 β 1 γ 1 bound to AMP and R734/R739 as well as partially active nonphosphorylated AMPK bound to R734 and AMP and phosphorylated AMPK bound to R734 in the absence of added nucleotides at <3-Å resolution. These structures and associated analyses identified a novel conformational state of the AMPK autoinhibitory domain associated with partial kinase activity and provide new insights into phosphorylation-dependent activation loop stabilization in AMPK., (© 2019 Yan et al.)

Over-expression of the Hsp70 molecular chaperone prevents protein aggregation and ameliorates neurodegenerative disease phenotypes in model systems. We identified an Hsp70 activator, MAL1-271, that reduces α-synuclein aggregation in a Parkinson's Disease model. We now report that MAL1-271 directly increases the ATPase activity of a eukaryotic Hsp70. Next, twelve MAL1-271 derivatives were synthesized and examined in a refined α-synuclein aggregation model as well as in an assay that monitors maturation of a disease-causing Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) mutant, which is also linked to Hsp70 function. Compared to the control, MAL1-271 significantly increased the number of cells lacking α-synuclein inclusions and increased the steady-state levels of the CFTR mutant. We also found that a nitrile-containing MAL1-271 analog exhibited similar effects in both assays. None of the derivatives exhibited cellular toxicity at concentrations up to 100 μm, nor were cellular stress response pathways induced. These data serve as a gateway for the continued development of a new class of Hsp70 agonists with efficacy in these and potentially other disease models., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Soluble Guanylate Cyclase (sGC) is the intracellular receptor of Nitric Oxide (NO). The activation of sGC results in the conversion of Guanosine Triphosphate (GTP) to the secondary messenger cyclic Guanosine Monophosphate (cGMP). cGMP modulates a series of downstream cascades through activating a variety of effectors, such as Phosphodiesterase (PDE), Protein Kinase G (PKG) and Cyclic Nucleotide-Gated Ion Channels (CNG). NO-sGC-cGMP pathway plays significant roles in various physiological processes, including platelet aggregation, smooth muscle relaxation and neurotransmitter delivery. With the approval of an sGC stimulator Riociguat for the treatment of Pulmonary Arterial Hypertension (PAH), the enthusiasm in the discovery of sGC modulators continues for broad clinical applications. Notably, through activating the NO-sGC-cGMP pathway, sGC stimulator and activator potentiate for the treatment of various diseases, such as PAH, Heart Failure (HF), Diabetic Nephropathy (DN), Systemic Sclerosis (SS), fibrosis as well as other diseases including Sickle Cell Disease (SCD) and Central Nervous System (CNS) disease. Here, we review the preclinical and clinical studies of sGC stimulator and activator in recent years and prospect for the development of sGC modulators in the near future., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

The current review is intended to highlight recent advances in the search of new and effective modulators of the metalloenzymes Carbonic Anhydrases (CAs, EC 4.2.1.1) expressed in humans (h). CAs reversibly catalyze the CO2 hydration reaction, which is of crucial importance in the regulation of a plethora of fundamental processes at cellular level as well as in complex organisms. The first section of this review will be dedicated to compounds acting as activators of the hCAs (CAAs) and their promising effects on central nervous system affecting pathologies mainly characterized from memory and learning impairments. The second part will focus on the emerging chemical classes acting as hCA inhibitors (CAIs) and their potential use for the treatment of diseases., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Introduction: Caspase-3 plays a leading role in apoptosis and on activation, it cleaves many protein substrates in cells and causes cell death. Since many chemotherapeutics are known to induce apoptosis in cancer cells, promotion or activation of apoptosis via targeting apoptosis regulators has been suggested as a promising strategy for anticancer drug discovery. In this paper, we studied the interaction of 1,2,4-Oxadiazoles derivatives with anticancer drug target enzymes (PDB ID 3SRC)., Methods: Molecular docking studies were performed on a series of 1,2,4-Oxadiazoles derivatives to find out molecular arrangement and spatial requirements for their binding potential for caspase-3 enzyme agonistic affinity to treat cancer. The Autodock 4.2 and GOLD 5.2 molecular modeling suites were used for the molecular docking analysis to provide information regarding important drug receptor interaction., Results and Conclusion: Both suites explained the spatial disposition of the drug with the active amino acid in the ligand binding domain of the enzyme. The amino acid asparagine 273 (ASN 273) of target has shown hydrogen bond interaction with the top ranked ligand., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: Paraoxonase 1 (PON1) is a paraoxonase, arylesterase and lactonase associated with protection of lipoproteins and cell membranes against oxidative modification., Objective: Based on antioxidative properties of PON1 and significance of 1,3,4-thiadiazoles in pharmaceutical chemistry, herein we aimed to evaluate the potentials of 1,3,4-thiadiazole derivatives as PON1 activators., Methods: 2-[[5-(2,4-Difluoro/dichlorophenylamino)-1,3,4-thiadiazol-2-yl]thio]acetophenone derivatives (1-18) were in vitro evaluated for their activator effects on PON1 which was purified using ammonium sulfate precipitation (60-80%) and DEAE-Sephadex anion exchange chromatography. Molecular docking studies were performed for the detection of affinities of all compounds to the active site of PON1. Moreover, Absorption, Distribution, Metabolism and Excretion (ADME) properties of all compounds were also in silico predicted. In silico molecular docking and ADME studies were carried out according to modules of Schrodinger's Maestro molecular modeling package., Results: All compounds, particularly compounds 10, 13 and 17, were determined as promising PON1 activators and apart from compound 1, all of them were detected in the active site of PON1. Besides, ADME results indicated that all compounds were potential orally bioavailable drug-like molecules., Conclusion: PON1 activators, compounds 10, 13 and 17 stand out as potential drug candidates for further antioxidant studies and these compounds can be investigated for their therapeutic effects in many disorders such as atherosclerosis, diabetes mellitus, obesity, chronic liver inflammation and many more., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

A new series of nonquaternary conjugates for reactivation of both nerve agents and pesticides inhibited hAChE were described in this paper. It was found that substituted salicylaldehydes conjugated to aminobenzamide through piperidine would produce efficient reactivators for sarin, VX and tabun inhibited hAChE, such as L6M1R3, L6M1R5 to L6M1R7, L4M1R3 and L4M1R5 to L4M1R7. The in vitro reactivation experiment for pesticides inhibited hAChE of these new synthesized oximes were conducted for the first time. Despite they were less efficient than obidoxime, some of them were highlighted as equal or more efficient reactivators in comparison to 2-PAM. It was found that introduction of peripheral site ligands could increase oximes' binding affinity for inhibited hAChE in most cases, which resulted in greater reactivation ability., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Lecithin:cholesterol acyltransferase (LCAT) and LCAT-activating compounds are being investigated as treatments for coronary heart disease (CHD) and familial LCAT deficiency (FLD). Herein we report the crystal structure of human LCAT in complex with a potent piperidinylpyrazolopyridine activator and an acyl intermediate-like inhibitor, revealing LCAT in an active conformation. Unlike other LCAT activators, the piperidinylpyrazolopyridine activator binds exclusively to the membrane-binding domain (MBD). Functional studies indicate that the compound does not modulate the affinity of LCAT for HDL, but instead stabilizes residues in the MBD and facilitates channeling of substrates into the active site. By demonstrating that these activators increase the activity of an FLD variant, we show that compounds targeting the MBD have therapeutic potential. Our data better define the substrate binding site of LCAT and pave the way for rational design of LCAT agonists and improved biotherapeutics for augmenting or restoring reverse cholesterol transport in CHD and FLD patients., Competing Interests: KM, SY, BB, LC, AG, WY, LF, DM, AS, AR, AJ, JT No competing interests declared

2-Hydroxy-oleic acid (2OHOA) is a potent anticancer drug that induces cancer cell cycle arrest and apoptosis. Previous studies have suggested that 2OHOA's anticancer effect is mediated by SMS activation in cancer cells, including A549 and U118 cells. To confirm this phenomenon, in this study, we treated both A549 and U118 cells with 2OHOA and measured SMS activity. To our surprise, we found neither 2OHOA-mediated SMS activation nor sphingomyelin accumulation in the cells. However, we noted that 2OHOA significantly reduces phosphatidylcholine in these cells. We also did not observe 2OHOA-mediated SMS activation in mouse tissue homogenates. Importantly, 2OHOA inhibited rather than activated recombinant SMS1 (rSMS1) and rSMS2 in a dose-dependent fashion. Intra-gastric treatment of C57BL/6J mice with 2OHOA for 10 days had no effects on liver and small intestine SMS activities and plasma sphingomyelin levels. The treatment inhibited lysophosphatidylcholine acyltransferase (LPCAT) activity, consistent with the aforementioned reduction in plasma phosphatidylcholine. Because total cellular phosphatidylcholine is used as a predictive biomarker for monitoring tumor responses, the previously reported 2OHOA-mediated cancer suppression could be related to this phosphatidylcholine reduction, which may influence cell membrane structure and properties. We conclude that 2OHOA is not a SMS activator and that its anticancer property may be related to an effect on phosphatidylcholine metabolism.

The NAD + -dependent deacetylase SIRT1 plays important roles in several physiological processes such as transcription, genome stability, stress responses, and aging. Due to its diverse role in metabolisms, SIRT1 has emerged as a potential therapeutic target in many human disorders such as type II diabetes, cardiovascular and neurodegenerative diseases, and cancer. Recent studies have reported that modulation of SIRT1 activity by phenolic activators like resveratrol and some 1,4-dihydropyridines (1,4-DHPs) can inhibit tumor growth by promoting apoptosis in cancer cells. However, the mechanism of SIRT1 activation is still not clear. In this report, we have tried to elucidate the mechanism of SIRT1 activation from studies on its interaction with a synthetic 1,4-DHP derivative (DHP-8; 3,5-diethoxy carbonyl-4-(4-nitrophenyl)-2,6-dimethyl-1,4-dihydropyridine) using molecular modeling, docking, simulation, and free energy analyses. Owing to the absence of full-length human SIRT1 structure, multi-template based modeling approach was opted followed by docking of DHP-8 at its allosteric site. In presence of DHP-8, the overall conformation of SIRT1 was found to be more stable (especially at its substrate binding sites) with a large structural variation at its N-terminal domain while bound to substrate p53 or p53-W. Determination of the MM/PBSA free energy indicated that the binding of DHP-8 to SIRT1 significantly increased the binding affinity of SIRT1 to its substrate p53-W as well as to NAD + . Overall, this study depicts the atomistic detailed mechanism for the direct activation of SIRT1 by a 1,4-DHP. This would serve to develop new SIRT1 activators for future therapeutic perspectives.

Antithrombin (AT) is a serpin that inhibits mainly thrombin and fXa after being activated by binding to glycosaminoglycans as heparin and heparan sulfate. Upon binding, the native AT conformation, relatively inactive as a protease inhibitor, is converted to an activated form. Recently, a new compound, named TMI, was discovered in our group with nanomolar affinity to antithrombin, and shown to be able to induce a partial activation of antithrombin. As TMI represents an original scaffold for structural optimizations aiming the development of new antithrombotic drugs, the present work demonstrated, through a series of molecular dynamics simulations, that TMI is able to modulate AT reactive center loop flexibility similarly to what is observed to heparin, as well as exposing AT P1 residue, Arg393. These results represent the first atomic level indication of AT conformational activation by TMI, and may offer a predictive basis for future studies aiming TMI structural optimization.

Among cationic molecules that can modulate ribozyme activities, polyamines act as both activator and inhibitor of ribozyme reactions partly due to their structural flexibility. Restriction of structural flexibility of polyamines may allow them to emphasize particular modulation effects. We examined eight stereoisomers of a synthetic pentamine bearing three cyclopentane rings. In the reaction of a structurally unstable group I ribozyme, three stereoisomers exhibited distinct effects as inhibitor, an additive with a neutral effect, and also as an activator., (Copyright © 2018 Elsevier Inc. All rights reserved.)

ZFAND5/ZNF216, a member of the zinc finger AN1-type domain family, is abundant in heart and brain, but is induced in skeletal muscle during atrophy (although not in proteotoxic stress). Because mice lacking ZFAND5 exhibit decreased atrophy, a role in stimulating protein breakdown seemed likely. Addition of recombinant ZFAND5 to purified 26S proteasomes stimulated hydrolysis of ubiquitinated proteins, short peptides, and ATP. Mutating its C-terminal AN1 domain abolished the stimulation of proteasomal peptidase activity. Mutating its N-terminal zinc finger A20 domain, which binds ubiquitin chains, prevented the enhanced degradation of ubiquitinated proteins without affecting peptidase activity. Mouse embryonic fibroblast (MEF) cells lacking ZFAND5 had lower rates of protein degradation and proteasomal activity than WT MEFs. ZFAND5 addition to cell lysates stimulated proteasomal activity and protein degradation. Unlike other proteasome regulators, ZFAND5 enhances multiple 26S activities and overall cellular protein breakdown., Competing Interests: The authors declare no conflict of interest.

Naturally occurring phytohormones have shown distinguished potential in chemoprevention and treatment of chronic inflammatory diseases in mammalian cells. Strigolactones (SLs) are a class of carotenoid-derived lactones regulating many aspects of plant development and recently recognized as phytohormones with promising anticancer activity. In this study, GR24, a synthetic analog and representative of SLs, induced the expression of phase II detoxifying enzymes such as HO-1 and NQO1 in hepatic and macrophage cell lines under normal and inflammatory conditions, respectively. This effect has been found to be mediated by Nrf2 activation. In silico molecular docking against 16-mer peptide binding site on Keap1 suggested that GR24 may exert its biological activity by interfering with Keap1 and Nrf2 binding. GR24 also displayed remarkably potent inhibitory activity against the production of nitric oxide (NO) and molecular docking analysis on iNOS supported experimental data. Furthermore, GR24 dose dependently suppressed the LPS-induced iNOS expression at both mRNA and protein level. It also significantly decreased IL-1β release, mRNA expression of IL-1β and COX-2, as well as nuclear accumulation of NFҡB at the low micro molar range in LPS-stimulated murine macrophages. GR24 promoted AKT activation in insulin resistant skeletal muscle cells and downregulated the expression of enzymes, PEPCK and G6Pase control the rate limiting steps of gluconeogenesis in hepatic cells. The results of molecular docking and ADMET analyses indicated that GR24 might be classified as druggable molecule in drug design. Taken together, all results suggest that SLs can be promising multi-potent botanical leads for the mitigation of inflammatory-mediated chronic disorders., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Non-alcoholic fatty liver disease (NAFLD) is a clinical syndrome characterized by hepatic steatosis. NAFLD is closely linked to obesity, insulin resistance and dyslipidemia. AMP-activated protein kinase (AMPK) functions as an energy sensor and plays a central role in regulating lipid metabolism. In this study, we identified a series of novel pyrazolone AMPK activators using a homogeneous time-resolved fluorescence assay (HTRF) based on the AMPKα2β1γ1 complex. Compound 29 (C29) is a candidate compound that directly activated the kinase domain of AMPK with an EC50 value of 2.1-0.2 μmol/L and acted as a non-selective activator of AMPK complexes. Treatment of HepG2 cells with C29 (20, 40 μmol/L) dose-dependently inhibited triglyceride accumulation. Chronic administration of C29 (10, 30 mg/kg every day, po, for 5 weeks) significantly improved lipid metabolism in both the liver and the plasma of ob/ob mice. These results demonstrate that the AMPK activators could be part of a novel treatment approach for NAFLD and associated metabolic disorders.

In our search for novel small cytotoxic molecules potentially activating procaspase-3, we have designed and synthesized a series of novel N'-[(E)-arylidene]-2-(2,3-dihydro-3-oxo-4H-1,4-benzoxazin-4-yl)acetohydrazides (5, 6). Biological evaluation revealed that seven compounds, including 5h, 5j, 5k, 5l, 5n, 6a, and 6b, exhibited moderate to strong cytotoxicity against three human cancer cell lines (SW620, colon cancer; PC-3, prostate cancer; NCI-H23, lung cancer). Among these compounds, two most cytotoxic compounds (5h and 5j) displayed from 3- up to 10-fold higher potency than PAC-1 and 5-FU in three cancer cell lines tested. Three compounds 5j, 5k, and 5n were also found to display better caspases activation activity in comparison to PAC-1. Especially, compound 5k activated the level of caspases activity by 200% higher than that of PAC-1. From this study, three compounds 5j, 5k, and 5n could be considered as potential leads for further design and development of caspase activators and anticancer agents., (© 2018 Wiley-VHCA AG, Zurich, Switzerland.)

Background: Buckwheat is an important alternative crop and a raw material for functional food formulation. Phase II detoxification proteins/enzymes provide cytoprotective roles against oxidative stress and inflammation originating from various stressors. We aimed to identify and characterize potential phase II enzyme inducers from methanolic extracts of buckwheat flour, using an activity-guided fractionation based on the induction of quinone reductase (QR) (EC 1.6.5.2) in Hepa 1c1c7 cells., Results: We isolated the QR inducers N-trans-feruloyltyramine (I), syringic acid (II), quercetin (III) and myricetin (IV). The relative QR-inducing ability, as well as the concentration required to double QR specific activity (CD values, in parentheses), decreased in the order: quercetin (3.0 µmol L -1 ) > N-trans-feruloyltyramine (24 µmol L -1 ) > myricetin (58 µmol L -1 ) > syringic acid (5.4 mmol L -1 ). Quercetin and N-trans-feruloyltyramine exhibited the greatest extent of QR induction of an approximately four-fold maximum induction and these compounds also exhibited the greatest values for the ratio of IC 50 (i.e. level to reduce viability by 50%): CD values of 11 and > 8.3, respectively, among the four QR inducers isolated. Isobologram analyses for binary combinations of compounds I-IV revealed primarily antagonistic interactions for QR induction., Conclusion: These findings add to our understanding of the nutraceutical potential of buckwheat as a chemoprophylactic dietary component. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)

Carbonic anhydrase (CA) plays a key role in neuronal signaling, providing bicarbonate and proton ions for GABAergic and glutamatergic neuronal function. Activation of CA isoforms expressed in neurons have been shown to have implications in the prognosis of Alzheimer's disease and dementia, while inhibitors of CAs are clinically used in the treatment of epilepsy, emphasizing the importance of this family of enzymes in both disease and normal neuronal function. Previously, compounds have been reported to enhance activity of CAs in an aging rat model, but their mechanism of action was not known. We report the 1.6 Å resolution structure of an imidazole-based CA activator in complex with the ubiquitously-expressed human CA II. Based on the structure, a proposed mechanism of CA activation by the compound and its potential applications in the neurobiology of aging are discussed.

Glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) play an important function in various biochemical processes as they generate reducing power of the cell. Thus, metabolic reprogramming of reduced nicotinamide adenine dinucleotide phosphate (NADPH) homeostasis is reported to be a vital step in cancer progression as well as in combinational therapeutic approaches. In this study, N-benzoylindoles 9a--9d, which form the main framework of many natural indole derivatives such as indomethacin and N-benzoylindoylbarbituric acid, were synthesized through three easy and effective steps as an in vitro inhibitor effect of G6PD and 6PGD. The N-benzoylindoles inhibited the enzymatic activity with IC 50 in the range of 3.391505 μM for G6PD and 2.19-990 μM for 6PGD., (© 2018 Wiley Periodicals, Inc.)

PTPRJ is a receptor-like protein tyrosine phosphatase mainly known for its antiproliferative and tumor-suppressive functions. PTPRJ dephosphorylates several growth factors and their receptors, negatively regulating cell proliferation and migration. We recently identified a disulfide-bridged nonapeptide, named PTPRJ-19 (H-[Cys-His-His-Asn-Leu-Thr-His-Ala-Cys]-OH), which activates PTPRJ, thereby causing cell growth inhibition and apoptosis of both cancer and endothelial cells. With the aim of replacing the disulfide bridge by a chemically more stable moiety, we have synthesized and tested a series of lactam analogues of PTPRJ-19. This replacement led to analogues with higher activity and greater stability than the parent peptide., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The Polo-like kinases (Plks) are an evolutionary conserved family of Ser/Thr protein kinases that possess, in addition to the classical kinase domain at the N-terminus, a C-terminal polo-box domain (PBD) that binds to phosphorylated proteins and modulates the kinase activity and its localization. Plk1, which regulates the formation of the mitotic spindle, has emerged as a validated drug target for the treatment of cancer, because it is required for numerous types of cancer cells but not for the cell division in noncancer cells. Here, we employed chemical biology methods to investigate the allosteric communication between the PBD and the catalytic domain of Plk1. We identified small compounds that bind to the catalytic domain and inhibit or enhance the interaction of Plk1 with the phosphorylated peptide PoloBoxtide in vitro. In cells, two new allosteric Plk1 inhibitors affected the proliferation of cancer cells in culture and the cell cycle but had distinct phenotypic effects on spindle formation. Both compounds inhibited Plk1 signaling, indicating that they specifically act on Plk1 in cultured cells.

Glucokinase (GK) is an enzyme that plays an important role as a glucose sensor while maintaining whole body glucose homeostasis. Allosteric activators of GK (GKAs) have the potential to treat type 2 diabetes mellitus. To identify novel GKAs, a series of compounds based on a thiophenyl-pyrrolidine scaffold were designed and synthesized. In this series, compound 38 was found to inhibit glucose excursion in an oral glucose tolerance test (OGTT) in mice. Optimization of 38 using a zwitterion approach led to the identification of the novel GKA 59. GKA 59 exhibited potent blood glucose control in the OGTT test as well as a favorable safety profile. Owing to low pancreatic distribution, compound 59 primarily activates GK in the liver. This characteristic could overcome limitations of other GKAs, such as hypoglycemia, increased plasma triglycerides, and loss of efficacy., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Polyamines are a promising class of molecules that can modulate RNA enzyme activities. To analyze the effects of the number of amine moieties systematically, we employed four polyamines sharing dimethylene units to connect amine moieties. As a model RNA enzyme, we used a structurally unstable group I ribozyme, which was activated most and least efficiently by tetraethylenepentamine and diethylenetriamine respectively.

AMP-activated protein kinase (AMPK) is an evolutionary conserved and ubiquitously expressed serine/threonine kinase playing a central role in the coordination of energy homeostasis. Based on the beneficial outcomes of its activation on metabolism, AMPK has emerged as an attractive target for the treatment of metabolic diseases. Identification of novel downstream targets of AMPK beyond the regulation of energy metabolism has renewed considerable attention in exploiting AMPK signaling for novel therapeutic targeting strategies including treatment of cancer and inflammatory diseases. The complexity of AMPK system with tissue- and species-specific expression of multiple isoform combination regulated by various inputs, post-traductional modifications and subcellular locations presents unique challenges for drug discovery. Here, we review the most recent advances in the understanding of the mechanism(s) of action of direct small molecule AMPK activators and the potential therapeutic opportunities., (Copyright © 2018 Elsevier Inc. All rights reserved.)

As one of the main receptors of a second messenger, cGMP, cGMP-dependent protein kinase (PKG) isoforms I and II regulate distinct physiological processes. The design of isoform-specific activators is thus of great biomedical importance and requires detailed structural information about PKG isoforms bound with activators, including accurate positions of hydrogen atoms and a description of the hydrogen bonding and water architecture. Here, we determined a 2.2 Å room-temperature joint X-ray/neutron (XN) structure of the human PKG II carboxyl cyclic nucleotide binding (CNB-B) domain bound with a potent PKG II activator, 8-pCPT-cGMP. The XN structure directly visualizes intermolecular interactions and reveals changes in hydrogen bonding patterns upon comparison to the X-ray structure determined at cryo-temperatures. Comparative analysis of the backbone hydrogen/deuterium exchange patterns in PKG II:8-pCPT-cGMP and previously reported PKG Iβ:cGMP XN structures suggests that the ability of these agonists to activate PKG is related to how effectively they quench dynamics of the cyclic nucleotide binding pocket and the surrounding regions.

Across all families of enzymes, only a dozen or so distinct classes of non-natural small molecule activators have been characterized, with only four known modes of activation among them. All of these modes of activation rely on naturally evolved binding sites that trigger global conformational changes. Among the enzymes that are of greatest interest for small molecule activation are the seven sirtuin enzymes, nicotinamide adenine dinucleotide (NAD+)-dependent protein deacylases that play a central role in the regulation of healthspan and lifespan in organisms ranging from yeast to mammals. However, there is currently no understanding of how to design sirtuin-activating compounds beyond allosteric activators of SIRT1-catalyzed reactions that are limited to particular substrates. Here, we introduce a general mode of sirtuin activation that is distinct from the known modes of enzyme activation. Based on the conserved mechanism of sirtuin-catalyzed deacylation reactions, we establish biophysical properties of small molecule modulators that can in principle result in enzyme activation for diverse sirtuins and substrates. Building upon this framework, we propose strategies for the identification, characterization and evolution of hits for mechanism-based enzyme activating compounds.

Mutations in PINK1, which impair its catalytic kinase activity, are causal for autosomal recessive early-onset Parkinson's disease (PD). Various studies have indicated that the activation of PINK1 could be a useful strategy in treating neurodegenerative diseases, such as PD. Herein, it is shown that the anthelmintic drug niclosamide and its analogues are capable of activating PINK1 in cells through the reversible impairment of the mitochondrial membrane potential. With these compounds, for the first time, it is demonstrated that the PINK1 pathway is active and detectable in primary neurons. These findings suggest that niclosamide and its analogues are robust compounds for the study of the PINK1 pathway and may hold promise as a therapeutic strategy in PD and related disorders., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Carbonic anhydrases (CAs) play an important function in various physiological and pathological processes. Therefore, many researchers work in this field in order to design and synthesize new drugs. Both inhibitors and activators of CAs, which are associated with the diagnosis and treatment of many diseases, are very important. The emergence of the use of CA activators in the treatment of Alzheimer has led many scholars to work on this issue. In this study, CA activators and inhibitors are determined. The crown ethers compounds (1, 2, 3, 6, 7, 8, and 9) were found to cause activation on enzyme activities of hCA I and II. The AC 50 values on hCA I and II of the compounds are in the range of 4.6565-374.979 μM. The 4 (IC 50 ; 1.301 and 3.215 μM for hCA I and II) and 5 (IC 50 ; 73.96 and 378.5 μM for hCA I and II) compounds were found to cause inhibition on enzyme activities of hCA I and II., (© 2018 Wiley Periodicals, Inc.)

Panax ginseng as a traditional Chinese medicine has been extensively used for the treatment of many diseases, especially in prolonging life and anti-tumor. Dammarane-type triterpenoids from P. ginseng have diverse beneficial effects and their chemical structures can be modified in the gastrointestinal tract after oral administration. In this paper, the dammarane-type triterpenoids were isolated from artificial gastric juice incubate of total saponins in the stems and leaves of P. ginseng through column chromatographic methods and their chemical structures were determined based on spectral data. Two new dammarane-type triterpenoids named ginsenotransmetins B (1) and C (2), along with twenty-nine known compounds (3-31), were obtained. All 31 compounds isolated were investigated for their activities of SIRT1 using SIRT1 fluorometric drug discovery assay kit. Among them, compounds 11, 17, 18, 20, 23, 24, 28, and 29, which were found to be potential as SIRT1 activators, exhibited significant stimulation of SIRT1 activity. The results showed that these compounds may be considered to be a useful medicinal resource for prolonging life and anti-tumor. In addition, the results were helpful to explain the longevity effect of ginseng from the new field of view., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Telomerase Activator 65 (TA-65), a compound extracted from Astragalus membranaceus has been used in Chinese traditional medicine for extending lifespan. Scarce information exists on the effects of TA-65 on parameters of metabolic syndrome (MetS)., Methods: We recruited 40 patients with MetS to determine the effects of TA-65 on dyslipidemias, hypertension, and oxidative stress in this at-risk population. The study was a double-blind, randomized crossover design in which patients were allocated to consume either 16 mg daily of a TA-65 supplement or a placebo for 12 weeks. Following a 3-week washout, participants were allocated to the alternate treatment for an additional 12 weeks. Anthropometric and biological markers were measured at the end of each treatment. Plasma lipids, glucose, CReactive Protein (CRP), liver enzymes, and glycosylated hemoglobin were measured using a Cobas c-111. Inflammatory cytokines were measured by Luminex technology and markers of oxidative stress by the use of spectroscopy., Results: Compared to the placebo period, HDL cholesterol (HDL-C) was higher while body mass index, waist circumference, and the LDL/HDL ratio were lower (p < 0.05) during TA-65 treatment. In addition, plasma tumor necrosis factor-α (TNF-α) was lower during the TA-65 period (p < 0.05). Positive correlations were observed in changes between the placebo and the TA-65 periods in HDL-C and CRP (r = -0.511, p < 0.01), alanine aminotransferase (r = -0.61, p < 0.001) and TNF-α (r = -0.550, p < 0.001) suggesting that the favorable changes observed in HDL were associated with decreases in inflammation., Conclusion: TA-65 improved key markers of cardiovascular disease risk, which were also associated with reductions in inflammation., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Protein-ligand interactions can be evaluated by a number of different biophysical methods. Here we describe some of the experimental methods that we have used to generate AMPK protein reagents and characterize its interactions with direct synthetic activators. Recombinant heterotrimeric AMPK complexes were generated using standard molecular biology methods by expression either in insect cells via infection with three different viruses or more routinely in Escherichia coli with a tricistronic expression vector. Hydrogen/deuterium exchange (HDX) coupled with mass spectrometry was used to probe protein conformational changes and potential binding sites of activators on AMPK. X-ray crystallographic studies were carried out on crystals of AMPK with bound ligands to reveal detailed molecular interactions formed by AMPK activators at near-atomic resolution. In order to gain insights into the mechanism of enzyme activation and to probe the effects of AMPK activators on kinetic parameters such as Michaelis-Menten constant (K m ) or maximal reaction velocity (V max ), we performed classical enzyme kinetic studies using radioactive 33 P-ATP-based filter assay. Equilibrium dissociation constants (K D ) and on and off rates of ligand binding were obtained by application of surface plasmon resonance (SPR) technique.

Recent bioinformatic analyses identified proteasome assembly chaperone-like proteins, PbaA and PbaB, in archaea. PbaB forms a homotetramer and functions as a proteasome activator, whereas PbaA does not interact with the proteasome despite the presence of an apparent C-terminal proteasome activation motif. We revealed that PbaA forms a homopentamer predominantly in the closed conformation with its C-terminal segments packed against the core domains, in contrast to the PbaB homotetramer with projecting C-terminal segments. This prompted us to create a novel proteasome activator based on a well-characterized structural framework. We constructed a panel of chimeric proteins comprising the homopentameric scaffold of PbaA and C-terminal segment of PbaB and subjected them to proteasome-activating assays as well as small-angle X-ray scattering and high-speed atomic force microscopy. The results indicated that the open conformation and consequent proteasome activation activity could be enhanced by replacement of the crystallographically disordered C-terminal segment of PbaA with the corresponding disordered segment of PbaB. Moreover, these effects can be produced just by incorporating two glutamate residues into the disordered C-terminal segment of PbaA, probably due to electrostatic repulsion among the negatively charged segments. Thus, we successfully endowed a functionally undefined protein with proteasome-activating activity by modifying its C-terminal segment., (© The Author(s) 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Introduction: It is well known that cancer cells have an altered metabolism both to meet the energy needs and to provide initial molecules for the synthesis of macromolecules. To cope with the new metabolic state, different forms of certain enzymes are expressed in extreme amounts. These enzymes are seen as very attractive targets to deal with cancer. Pyruvate kinases isoenzyme M2 (PKM2) is a key enzyme that determines whether glucose is used for energy or synthesis of biosynthetic molecules. The dimeric form of PKM2 main form in several cancer cells serves the formation of synthetic precursors required for the cell growth and proliferation from glycolytic intermediates., Areas Covered: This article reviews appropriate publications on PKM2 activators from the points of view of synthesis and biological activities between 2011-2017. Herein, based on the chemical structure, PKM2 activators are classified into sulfonamide, phenolic, carboxamide and pyridopyrimidinone derivatives., Expert Opinion: PKM2 activation inhibits cell growth and proliferation by decreasing a number of biomolecules required for cell building. Therefore; PKM2 activators are considered as an ideal drug for or the treatment of many cancer pathogens. It is necessary to discover new, more active and selective compounds for PKM2 activation.

Background: Clinical treatment of heart failure is still suffering from limited efficacy and unfavorable side effects. The recently developed group of agents, the myosin motor activators, act directly on cardiac myosin resulting in an increased force generation and prolongation of contraction. The lead molecule, omecamtiv mecarbil is now in human 3 stage. In addition to the promising clinical data published so far, there are new in vitro results indicating that the effect of omecamtiv mecarbil on contractility is rate-dependent. Furthermore, omecamtiv mecarbil was shown to activate cardiac ryanodine receptors, an effect that may carry proarrhythmic risk., Methods: These new results, together with the controversial effects of the drug on cardiac oxygen consumption, are critically discussed in this review in light of the current literature on omecamtiv mecarbil., Results: In therapeutically relevant concentrations the beneficial inotropic effect of the agent is not likely affected by these new results - in accordance with the good clinical data. At supratherapeutic concentrations, however, activation of cardiac ryanodine receptors may increase arrhythmia propensity, and the stronger effect on diastolic than systolic cell shortening, observed at higher pacing frequencies, may decrease or offset the inotropic effect of omecamtiv mecarbil., Conclusion: Further studies with definitely supratherapeutical concentrations of omecamtiv mecarbil should be designed to map the actual risk of these potentially harmful side-effects., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

The microtubule motor kinesin-1 interacts via its cargo-binding domain with both microtubules and organelles, and hence plays an important role in controlling organelle transport and microtubule dynamics. In the absence of cargo, kinesin-1 is found in an autoinhibited conformation. The molecular basis of how cargo engagement affects the balance between kinesin-1's active and inactive conformations and roles in microtubule dynamics and organelle transport is not well understood. Here we describe the discovery of kinesore, a small molecule that in vitro inhibits kinesin-1 interactions with short linear peptide motifs found in organelle-specific cargo adaptors, yet activates kinesin-1's function of controlling microtubule dynamics in cells, demonstrating that these functions are mechanistically coupled. We establish a proof-of-concept that a microtubule motor-cargo interface and associated autoregulatory mechanism can be manipulated using a small molecule, and define a target for the modulation of microtubule dynamics., Competing Interests: The authors declare no conflict of interest.