Glucokinase activators. Pharm Pat Anal. 2012;1:301-311. [PMID: 24236843 DOI: 10.4155/ppa.12.26]

Design, Synthesis, Molecular Docking and In vitro Biological Evaluation of Benzamide Derivatives as Novel Glucokinase Activators

Background:

Glucokinase (GK) is a cytoplasmic enzyme that metabolises glucose to glucose-6-phosphate and supports adjusting blood glucose levels within the normal range in humans. In pancreatic β-cells, it plays a leading role in governing the glucose-stimulated secretion of insulin, and in liver hepatocyte cells, it controls the metabolism of carbohydrates. GK acts as a promising drug target for treating patients with type 2 diabetes mellitus (T2DM).

Objectives:

The present work has been designed to discover some novel substituted benzamide derivatives

Method:

This work involved designing novel benzamide derivatives and their screening by docking studies to determine the binding interactions for the best-fit conformations in the binding site of the GK enzyme. Based on the results of docking studies, the selected molecules were synthesized and tested for in vitro GK enzyme assay. The structures of newly synthesized products were confirmed by IR, NMR, and mass spectroscopy.

Results:

Amongst the designed derivatives, compounds 4c, 4d, 4e, 5h, 5j, 5l, 5m, 5n, 5p, and 5r have shown better binding energy than the native ligand present in the enzyme structure. The synthesized compounds were subjected to in vitro GK enzyme assay. Out of all, compounds 4c, 4d, 5h, 5l, and 5n showed more GK activation than control.

Conclusion::

From the present results, we have concluded that the synthesized derivatives can activate the human GK enzyme effectively, which can be helpful in the treatment of T2DM.

Investigation of phytoconstituents of Enicostemma littorale as potential glucokinase activators through molecular docking for the treatment of type 2 diabetes mellitus

Glucokinase (GK) is an enzyme involved in synthesising glucose into glucose-6 phosphate and serves a crucial function in glucose sensing. Therefore, agents that induce GK activation could be used to treat T2DM. The present work has been carried out to investigate the GK activation potential of phytoconstituents of Enicostemma littorale through molecular docking. All the phytoconstituents have been screened through the Lipinski rule of 5, Veber's rule, and ADMET properties. From these initial screening, only Apigenin, Ferulic acid, Genkwanin, p-coumaric acid, Protocatechuic acid, Syringic acid, and Vanillic acid have been selected to perform molecular docking studies. The binding free energy and binding mode of the native ligand in the allosteric site of the enzyme have been considered the reference for the other molecules' validation. The native ligand has exhibited - 7.2 kcal/mol binding free energy, whereas; it has formed four hydrogen bonds with THR-228, LYS-169, ASP-78, and GLY-81. Based on these findings, the interactions of phytoconstituents have been justified. Apigenin, genkwanin, and swertiamarin exhibited - 8.7, - 7.5, and - 8.3 kcal/mol binding free energy, respectively, which indicates better enzyme activation than the native ligand. Swertiamarin has formed 08 hydrogen bonds with allosteric amino acid residues, which confirms the excellent enzyme activation by these phytoconstituents. We concluded that if we can isolate and consume the exact active phytoconstituents (GK activators) from this plant, we can use them effectively to treat T2DM. More GK activators can be developed by considering them as a natural lead moiety.

Recent Developments in Medicinal Chemistry of Allosteric Activators of Human Glucokinase for Type 2 Diabetes Mellitus Therapeutics

BACKGROUND

Glucokinase (GK), a cytoplasmic enzyme catalyzes the metabolism of glucose to glucose- 6-phosphate with the help of ATP and aids in the controlling of blood glucose levels within the normal range in humans. In pancreatic β-cells, it plays a chief role by controlling the glucose-stimulated secretion of insulin and in liver hepatocyte cells, it controls the metabolism of carbohydrates. GK acts as a promising drug target for the pharmacological treatment of patients with type 2 diabetes mellitus (T2DM) as it plays an important role in the control of carbohydrate metabolism.

METHODS

Data used for this review was based on the search from several science databases as well as various patent databases. The main data search terms used were allosteric GK activators, diabetes mellitus, type 2 diabetes, glucokinase, glucokinase activators and human glucokinase.

RESULTS

This article discusses an overview of T2DM, the biology of GK, the role of GK in T2DM, recent updates in the development of small molecule GK activators reported in recent literature, mechanism of action of GK activators and their clinical status.

CONCLUSION

GK activators are the novel class of pharmacological agents that enhance the catalytic activity of GK enzyme and display their antihyperglycemic effects. Broad diversity of chemical entities including benzamide analogues, carboxamides, acrylamides, benzimidazoles, quinazolines, thiazoles, pyrimidines, pyridines, orotic acid amides, amino acid derivatives, amino phosphates and urea derivatives have been synthesized in past two decades as potent allosteric activators of GK. Presently, the pharmaceutical companies and researchers are focusing on the design and development of liver-selective GK activators for preventing the possible adverse effects associated with GK activators for the long-term treatment of T2DM.

In-silico evidences for binding of Glucokinase activators to EGFR C797S to overcome EGFR resistance obstacle with mutant-selective allosteric inhibition

The tyrosine kinase inhibitors (TKI) against epidermal growth factor receptor (EGFR) are generally utilized as a part of patients with non-small cell lung carcinoma (NSCLC). However, EGFR T790M mutation results in resistance to most clinically available EGFR TKIs. Third-generation EGFR TKIs against the T790M mutation has been in active clinical development to triumph the resistance problem; they covalently bind with conserved Cys797 inside the EGFR active site, offering both potency and kinase-selectivity. Third generation drugs target C797, which makes the C797S resistance mutation more subtle. EGFR C797S mutation was accounted to be a main mechanism of resistance to the third-generation inhibitors. The C797S mutation gives off an impression of being an ideal target for conquering the acquired resistance to the third generation inhibitors. We have performed structure based-virtual screening strategies for binding of glucokinase activator to EGFR C797S, which can overcome EGFR resistance impediment with mutant-selective allosteric inhibition towards all kinds of mutant EGFR (T790M, L858R, TMLR) and WT EGFR. The final filter of Lipinski's Rule of Five, Jargan's Rule of Three and in silico ADME predictions gave 23 hits, which conform to Lipinski's rule and Jorgensen's rule and all their pharmacokinetic parameters are inside the appropriate range characterized for human use, in this manner demonstrating their potential as a drug-like molecule.

Pyridoxine dipharmacophore derivatives as potent glucokinase activators for the treatment of type 2 diabetes mellitus

Glucokinase is one of the promising targets for glucose-lowering agents, and the development of GK activators are now considered as one of the most promising strategies for the treatment of type 2 diabetes mellitus. In this work, a series of novel symmetric molecular constructs, in which two pyridoxine moieties are connected via sulfur-containing linkers, have been synthesized and tested in vitro for glucokinase activation potential. The enzyme activation rates by two most active compounds at 100 μM (~150% and 130%) were comparable to that of the reference agent PF-04937319 (~154%). Both leading compounds demonstrated low cytotoxicity and excellent safety profile in acute toxicity experiment in rats after oral administration with LD₅₀ exceeding 2000 mg/kg of body weight. Binding mode of the active compounds in comparison with the reference agent was studied using molecular docking. The leading compounds represent viable preclinical candidates for the treatment of type 2 diabetes mellitus, as well as a promising starting point for the design of structural analogs with improved activity.

Discovery of 2-pyridylureas as glucokinase activators

Glucokinase (GK) is the rate-limiting step for insulin release from the pancreas in response to high levels of glucose. Flux through GK also contributes to reducing hepatic glucose output. Since many individuals with type 2 diabetes appear to have an inadequacy or defect in one or both of these processes, identifying compounds that can allosterically activate GK may address this issue. Herein we report the identification and initial optimization of a novel series of glucokinase activators (GKAs). Optimization led to the identification of 33 as a compound that displayed activity in an oral glucose tolerance test (OGTT) in normal and diabetic mice.

Novel and emerging diabetes mellitus drug therapies for the type 2 diabetes patient

Type 2 diabetes mellitus is a metabolic disorder of deranged fat, protein and carbohydrate metabolism resulting in hyperglycemia as a result of insulin resistance and inadequate insulin secretion. Although a wide variety of diabetes therapies is available, yet limited efficacy, adverse effects, cost, contraindications, renal dosage adjustments, inflexible dosing schedules and weight gain significantly limit their use. In addition, many patients in the United States fail to meet the therapeutic HbA1c goal of < 7% set by the American Diabetes Association. As such new and emerging diabetes therapies with different mechanisms of action hope to address some of these drawbacks to improve the patient with type 2 diabetes. This article reviews new and emerging classes, including the sodium-glucose cotransporter-2 inhibitors, 11β-Hydroxysteroid dehydrogenase type 1 inhibitors, glycogen phosphorylase inhibitors; protein tyrosine phosphatase 1B inhibitors, G Protein-Coupled receptor agonists and glucokinase activators. These emerging diabetes agents hold the promise of providing benefit of glucose lowering, weight reduction, low hypoglycemia risk, improve insulin sensitivity, pancreatic β cell preservation, and oral formulation availability. However, further studies are needed to evaluate their safety profile, cardiovascular effects, and efficacy durability in order to determine their role in type 2 diabetes management.

A patent review of glucokinase activators and disruptors of the glucokinase--glucokinase regulatory protein interaction: 2011-2014

INTRODUCTION

Glucokinase (GK) is a key regulator of glucose homeostasis, and development of small molecule activators of this enzyme represents a promising new approach for the treatment of type 2 diabetes mellitus.

AREAS COVERED

This manuscript reviews small molecule patent disclosures between late 2011 and February 2014 for both GK activators (GKAs) and GK-glucokinase regulatory protein (GK-GKRP) disruptors. The review is organized by company and structural class.

EXPERT OPINION

The field of GKA research continues to progress, driven by research across many organizations. To date, > 20 candidates have entered clinical development with the most advanced in Phase II trials. Despite promising efficacy, a significant number of early candidates have been discontinued for various reasons including increased risk of hypoglycemia and lack of durability. Recent work in the field has focused on liver-selective activators, which have shown lower hypoglycemia risk, including the development of novel GK-GKRP disruptors that act to indirectly increase hepatic GK activity.

GKAs for diabetes therapy: why no clinically useful drug after two decades of trying?

Results of basic biochemical and physiological research, strongly endorsed by findings in human pathophysiology and genetics, had characterized the glucose phosphorylating enzyme glucokinase as a critical player in normal glucose homeostasis, diabetes mellitus, and hyperinsulinemic hypoglycemia, and identified the enzyme as a promising new drug target. R&D initiated in the early 1990s and directed at this target discovered glucokinase activators (GKAs) as a new class of potentially antidiabetic drugs. GKAs were characterized as nonessential allosteric activators that increase glucose affinity and V(max) of the enzyme, thus stimulating glucose metabolism in glucokinase expressing tissue, of foremost functional significance in the insulin producing pancreatic beta cells and the liver. The results of preclinical testing of GKAs by many pharmaceutical companies demonstrated uniformly high hypoglycemic efficacy in normal and diabetic animals. GKAs were also highly effective in Phase I trials in patients with type 2 diabetes mellitus (T2DM). However, results of a recent Phase II trial were less encouraging because patients developed hyperlipidemia and vascular hypertension, and the drug lost efficacy within several months. This outcome is prompting a reappraisal of the GKA strategy. In this opinion article, the 'pros and cons' of the strategy to use these compounds in diabetes management are critically reexamined and suggestions are made that might facilitate progress of GKA R&D that could still result in a novel antidiabetic medicine.

Strategies for the design of hepatoselective glucokinase activators to treat type 2 diabetes

INTRODUCTION

Type 2 diabetes mellitus (T2DM) represents a rapidly expanding healthcare challenge. There is a significant need for novel therapies to help patients achieve and maintain glycemic control in order to avoid the long-term microvascular and macrovascular complications associated with the disease. Small molecule allosteric activators of the glucokinase enzyme, an important regulator of glucose homeostasis, have emerged as a potential new class of therapeutics. Glucokinase activators have been shown to effectively lower fasting and postprandial glucose in T2DM patients; however, hypoglycemia emerged as a potential risk limiting their therapeutic potential. To mitigate this risk, recent efforts have focused on the design of liver-specific activators that seek to normalize hepatic glucose uptake and production without potentiating glucose-stimulated insulin secretion.

AREAS COVERED

The article reviews the various drug discovery strategies that have emerged for the development of candidates that selectively activate glucokinase in the liver. Literature from 2000 to 2012 is surveyed including scientific publications, patent applications, conferences and clinical trials.

EXPERT OPINION

Liver selective agents have proven to be an effective strategy for mitigating the hypoglycemia risk that has been historically associated with this mechanism. The ultimate therapeutic potential of this approach will depend on the results of longer patient studies which are currently being conducted with several clinical candidates. The discovery of these liver-specific activators has highlighted several challenges in the design of tissue-selective therapeutics, which will need to be overcome in the future.

The design and synthesis of indazole and pyrazolopyridine based glucokinase activators for the treatment of type 2 diabetes mellitus

Glucokinase activators represent a promising potential treatment for patients with Type 2 diabetes. Herein, we report the identification and optimization of a series of novel indazole and pyrazolopyridine based activators leading to the identification of 4-(6-(azetidine-1-carbonyl)-5-fluoropyridin-3-yloxy)-2-ethyl-N-(5-methylpyrazin-2-yl)-2H-indazole-6-carboxamide (42) as a potent activator with favorable preclinical pharmacokinetic properties and in vivo efficacy.