A comprehensive review on glucokinase activators: Promising agents for the treatment of Type 2 diabetes

Targeting Protein Kinases to Protect Beta-Cell Function and Survival in Diabetes

The prevalence of diabetes is increasing worldwide. Massive death of pancreatic beta-cells causes type 1 diabetes. Progressive loss of beta-cell function and mass characterizes type 2 diabetes. To date, none of the available antidiabetic drugs promotes the maintenance of a functional mass of endogenous beta-cells, revealing an unmet medical need. Dysfunction and apoptotic death of beta-cells occur, in particular, through the activation of intracellular protein kinases. In recent years, protein kinases have become highly studied targets of the pharmaceutical industry for drug development. A number of drugs that inhibit protein kinases have been approved for the treatment of cancers. The question of whether safe drugs that inhibit protein kinase activity can be developed and used to protect the function and survival of beta-cells in diabetes is still unresolved. This review presents arguments suggesting that several protein kinases in beta-cells may represent targets of interest for the development of drugs to treat diabetes.

Clinical investigation of glucokinase activators for the restoration of glucose homeostasis in diabetes

As a sensor, glucokinase (GK) controls glucose homeostasis, which progressively declines in patients with diabetes. GK maintains the equilibrium of glucose levels and regulates the homeostatic system set points. Endocrine and hepatic cells can both respond to glucose cooperatively when GK is activated. GK has been under study as a therapeutic target for decades due to the possibility that cellular GK expression and function can be recovered, hence restoring glucose homeostasis in patients with type 2 diabetes. Five therapeutic compounds targeting GK are being investigated globally at the moment. They all have distinctive molecular structures and have been clinically shown to have strong antihyperglycemia effects. The mechanics, classification, and clinical development of GK activators are illustrated in this review. With the recent approval and marketing of the first GK activator (GKA), dorzagliatin, GKA's critical role in treating glucose homeostasis disorder and its long-term benefits in diabetes will eventually become clear.

Molecular docking, pharmacokinetic prediction and molecular dynamics simulations of tankyrase inhibitor compounds with the protein glucokinase, induced in the development of diabetes

GCK is a protein that plays a crucial role in the sensing and regulation of glucose homeostasis, which associates it with disorders of carbohydrate metabolism and the development of several pathologies, including gestational diabetes. This makes GCK an important therapeutic target that has aroused the interest of researchers to discover GKA that are simultaneously effective in the long term and free of side effects. TNKS is a protein that interacts directly with GCK; recent studies have shown that it inhibits GCK action, which affects glucose detection and insulin secretion. This justifies our choice of TNKS inhibitors as ligands to test their effects on the GCK-TNKS complex. For this purpose, we investigated the interaction of the GCK-TNKS complex with 13 compounds (TNKS inhibitors and their analogues) using the molecular docking approach as a first step, after which the compounds that generated the best affinity scores were evaluated for drug similarity and pharmacokinetic properties. Subsequently, we selected the six compounds that generated high affinity and that were in accordance with the parameters of the drug rules as well as pharmacokinetic properties to ensure a molecular dynamics study. The results allowed us to favor the two compounds (XAV939 and IWR-1), knowing that even the tested compounds (TNKS 22, (2215914) and (46824343)) produced good results that can also be exploited. These results are therefore interesting and encouraging, and they can be exploited experimentally to discover a treatment for diabetes, including gestational diabetes.Communicated by Ramaswamy H. Sarma.

Efficacy and safety of dorzagliatin, a novel glucokinase activators, in the treatment of T2DM: A meta-analysis of randomized controlled trials

OBJECT

To evaluate the efficacy and safety of dorzagliatin for the treatment of type 2 diabetes (T2DM).

METHODS

Seven databases were systematically searched, spanning the interval from 2016 to August 2023. Randomized controlled trials (RCTS) comparing dorzagliatin with placebo for the treatment of T2DM were applicable for containing this study. The relevant data were extracted, and a meta-analysis was implemented using RevMan 5.4 software.

RESULTS

A total of 3 studies involving 1332 patients were included. We use glycated hemoglobin (HbA1c) levels as the major indicator of efficacy, FBG, 2h postprandial blood glucose, Homa-β and Homa-IR to be Secondary outcome measures. Compared with placebo group, dorzagliatin significantly reduced blood glucose levels as well as enhanced insulin resistance. In terms of safety, no serious adverse events occurred. However, lipid-related indicators, especially triglycerides levels, and the incidence of hypoglycemia were higher in patients in the dorzagliatin group compared with those in the control group, but the increase from baseline was mild.

CONCLUSIONS

Dorzagliatin exerted favorable effects in hypoglycemic control, effectively reduced the HbA1c, FBG, and 2h postprandial blood glucose levels in T2DM patients, stimulated the secretion of insulin during the initial phase, and exerted a consistent hypoglycemic effect. However, the incidence of adverse events such as elevated blood lipids and cardiovascular risk warrants further investigations through long-term clinical trials.

Glucokinase Inhibition: A Novel Treatment for Diabetes?

Chronic hyperglycemia increases pancreatic β-cell metabolic activity, contributing to glucotoxicity-induced β-cell failure and loss of functional β-cell mass, potentially in multiple forms of diabetes. In this perspective we discuss the novel paradoxical and counterintuitive concept of inhibiting glycolysis, particularly by targeted inhibition of glucokinase, the first enzyme in glycolysis, as an approach to maintaining glucose sensing and preserving functional β-cell mass, thereby improving insulin secretion, in the treatment of diabetes.

Transporter-Mediated Drug Delivery

Transmembrane transport of small organic and inorganic molecules is one of the cornerstones of cellular metabolism. Among transmembrane transporters, solute carrier (SLC) proteins form the largest, albeit very diverse, superfamily with over 400 members. It was recognized early on that xenobiotics can directly interact with SLCs and that this interaction can fundamentally determine their efficacy, including bioavailability and intertissue distribution. Apart from the well-established prodrug strategy, the chemical ligation of transporter substrates to nanoparticles of various chemical compositions has recently been used as a means to enhance their targeting and absorption. In this review, we summarize efforts in drug design exploiting interactions with specific SLC transporters to optimize their therapeutic effects. Furthermore, we describe current and future challenges as well as new directions for the advanced development of therapeutics that target SLC transporters.

Efficacy and safety of novel dual glucokinase activator dorzagliatin in type-2 diabetes A meta-analysis

BACKGROUND & AIMS

Glucokinase has a critical role in regulating glucose homeostasis in humans, and has been a target for diabetes drug development since 1990s. Dorzagliatin is a novel allosteric dual glucokinase activator targeting both pancreatic and hepatic glucokinase. No meta-analysis has analysed the efficacy and safety of dorzagliatin in type-2 diabetes (T2DM). We undertook this meta-analysis to address this knowledge-gap.

METHODS

Electronic databases were searched for RCTs involving T2DM patients receiving dorzagliatin in intervention arm, and placebo/active comparator in control arm. Primary outcome was to evaluate changes in HbA1c. Secondary outcomes were to evaluate alterations in blood glucose parameters, lipids, insulin-resistance and adverse events.

RESULTS

From initially screened 17 articles, data from 3 RCTs (1333 patients) was analysed. Over 12-24 weeks use, dorzagliatin had significantly higher lowering of HbA1c [MD -0.66% (95%CI: -0.74 to -0.59); P < 0.01; I² = 99%], fasting glucose [MD -32.03 mg/dl (95%CI: 45.12 to -18.94); P < 0.01; I² = 100%], 2-h post-prandial glucose [MD -43.49 mg/dl (95%CI: -46.26 to -40.72); P < 0.01; I² = 90%] along with greater number of patients achieving HbA1c<7% [OR 6.01 (95% CI: 2.50-14.46); P < 0.01; I² = 83%], as compared to placebo. Dorzagliatin was associated with significant elevation of triglycerides [MD 0.43 mmol/L (95%CI:0.30-0.56); P < 0.01; I² = 0%], greater occurrence of hyperlipidaemia [RR 1.52 (95% CI:1.05-2.18); P = 0.03; I² = 0%], and increase in body-weight [MD 0.40 kg (95%CI:0.06-0.75); P = 0.03; I² = 0%], compared to placebo. The occurrence of total-adverse-events [RR 1.43 (95%CI:1.11-1.83); P < 0.01; I² = 0%] but not severe adverse-events [RR 0.92 (95%CI:0.54-1.57); P = 0.76; I² = 0%] was significantly higher with dorzagliatin.

CONCLUSION

Dorzagliatin has good glycaemic efficacy and well tolerated over 6-months use. Mild increase in body-weight, serum triglycerides and overall adverse events remain issues of concern warranting further evaluation in longer clinical trials with active controls.

Efficacy and safety of dorzagliatin for type 2 diabetes mellitus: A meta-analysis and trial sequential analysis

Objective

To evaluate the efficacy and safety of dorzagliatin in the treatment of type 2 diabetes mellitus (T2DM) by using meta-analysis and trial sequential analysis (TSA).

Method

Search for clinical trials of dorzagliatin for T2DM in eight databases, with a time limit of build to July 2022. The included studies that met the requirements were carried out for meta-analysis and TSA.

Results

In terms of efficacy endpoints, meta-analysis showed that dorzagliatin decreased glycated hemoglobin A1c(HbA1c) [mean difference (MD) -0.65%, 95% confidence interval (CI) -0.76 ~ -0.54, P < 0.00001], fasting plasma glucose (FPG) (MD -9.22 mg/dL, 95% CI -9.99 ~ -8.44, P < 0.00001), 2 h postprandial glucose (2h-PPG) (MD -48.70 mg/dL, 95% CI -55.45 ~ -41.96, P < 0.00001), homeostasis model assessment 2 of insulin resistance (HOMA2-IR) (MD -0.07, 95% CI -0.14 ~ -0.01, P = 0.03) and increased homeostasis model assessment 2 of ß-cells function (HOMA2-β) (MD 2.69, 95% CI 1.06 ~ 4.31, P = 0.001) compared with placebo. And TSA revealed that the benefits observed for the current information set were conclusive, except for HOMA2-IR. In comparison with placebo, dorzagliatin increased triglyceride(TG) (MD 0.43 mmol/L, 95% CI 0.30 ~ 0.56, P < 0.00001), total cholesterol (TC) (MD 0.13 mmol/L, 95% CI 0.05 ~ 0.21, P = 0.001), body weight (MD 0.38 kg, 95% CI 0.12-0.63, P = 0.004) and body mass index (BMI) (MD 0.14 kg/m², 95% CI 0.05-0.24, P = 0.003), while low density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were comparable. And TSA demonstrated that TG, TC, body weight, and BMI were conclusive. In terms of safety endpoints, dorzagliatin increased total adverse events (AEs) [risk ratio (RR) 1.56, 95% CI 1.06 ~ 2.30, P = 0.03], while serious AEs, hyperlipidemia, and hypoglycaemia were all comparable. And TSA indicated that the results need to be confirmed by additional studies. Harbord regression showed no publication bias.

Conclusion

Dorzagliatin was effective in lowering glycemia, reducing insulin resistance and improving islet ß-cells function without affecting blood pressure, LDL-C, and HDL-C. Although dorzagliatin caused a mild increase in TG and TC, it did not increase the incidence of hyperlipidemia, and the small increases in body weight and BMI were not clinically significant enough. In terms of safety, the total AEs caused by dorzagliatin may be a cumulative effect of single AEs, with no drug-related adverse event being reported at a higher incidence than placebo alone. Dorzagliatin's serious AEs, hyperlipidemia, and hypoglycemia are comparable to that of placebo, and dorzagliatin has a good safety profile.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=371802 identifier: CRD42022371802.

Genetic and Pharmacological Inhibition of GCN2 Ameliorates Hyperglycemia and Insulin Resistance in Type 2 Diabetic Mice

It is well recognized that there is a strong and complex association between nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes (T2D). We previously demonstrated that genetic knockout or pharmacological inhibition of general control nondepressible kinase 2 (GCN2), a well-known amino acid sensor, alleviated hepatic steatosis and insulin resistance in obese mice. However, whether GCN2 affects the development of T2D remains unclear. After a high-fat diet (HFD) plus low-dose streptozotocin (STZ) treatments, Gcn2−/− mice developed less hyperglycemia, insulin resistance, hepatic steatosis, and oxidative stress than wild-type (WT) mice. Inhibition of GCN2 by intraperitoneal injection of 3 mg/kg GCN2iB (a specific inhibitor of GCN2) every other day for 6 weeks also ameliorated hyperglycemia, insulin resistance, hepatic steatosis, and oxidative stress in HFD/STZ- and leptin receptor deletion (db/db)-induced T2D mice. Moreover, depletion of hepatic GCN2 in db/db mice by tail vein injection of an AAV8-shGcn2 vector resulted in similar improvement in those metabolic disorders. The protective mechanism of GCN2 inhibition in T2D mice was associated with regulation of the glucose metabolic pathway, repression of lipogenesis genes, and activation of the Nrf2 pathway. Together, our data provide evidence that strategies to inhibit hepatic GCN2 activity may be novel approaches for T2D therapy.

Disruptions in hepatic glucose metabolism are involved in the diminished efficacy after chronic treatment with glucokinase activator

Glucokinase activators are regarded as potent candidates for diabetes treatment, however, in clinical studies on patients with type 2 diabetes, a diminishing efficacy was observed after chronic treatment with them. The mechanism of this reduction has not been elucidated, and whether it is a class effect of glucokinase activators remains inconclusive. Here, we firstly identified a diabetic animal model that shows the diminished efficacy after long-term treatment with MK-0941, a glucokinase activator that exhibited diminished efficacy in a clinical study, and we analyzed the mechanism underlying its diminished efficacy. In addition, we evaluated the long-term efficacy of another glucokinase activator, TMG-123. Goto-Kakizaki rats were treated with MK-0941 and TMG-123 for 24 weeks. The results showed that glycated hemoglobin A1C levels and plasma glucose levels decreased transiently but increased over time with the continuation of treatment in the MK-0941-treated group, while decreased continuously in the TMG-123-treated group. Only in the TMG-123-treated group, higher plasma insulin levels were shown at the later stage of the treatment period. For the mechanism analysis, we conducted a hepatic enzyme assay and liver perfusion study in Goto-Kakizaki rats after chronic treatment with MK-0941 and TMG-123, and revealed that, only in the MK-0941-treated group, the activity of glucose-6-phosphatase was increased, and hepatic glucose utilization was decreased compared to the non-treated group. These data indicate that disruptions in hepatic glucose metabolism are involved in the diminished efficacy of glucokinase activators.

Advances in computer-aided drug design for type 2 diabetes

INTRODUCTION

The number of diabetic patients is increasing, posing a heavy social and economic burden worldwide. Traditional drug development technology is time-consuming and costly, and the emergence of computer-aided drug design (CADD) has changed this situation. This study reviews the applications of CADD in diabetic drug designing.

AREAS COVERED

In this article, the authors focus on the advance in CADD in diabetic drug design by elaborating the discovery, including peroxisome proliferator-activated receptor (PPAR), G protein-coupled receptor 40 (GPR40), dipeptidyl peptidase-IV (DDP-IV), protein tyrosine phosphatase 1B (PTP1B), sodium-dependent glucose transporter 2 (SGLT-2), and glucokinase (GK). Some drug discovery of these targets is related to CADD strategies.

EXPERT OPINION

There is no doubt that CADD has contributed to the discovery of novel anti-diabetic agents. However, there are still many limitations and challenges, such as lack of co-crystal complex, dynamic simulations, water, and metal ion treatment. In the near future, artificial intelligence (AI) may be a promising strategy to accelerate drug discovery and reduce costs by identifying candidates. Moreover, AlphaFold, a deep learning model that predicts the 3D structure of proteins, represents a considerable advancement in the structural prediction of proteins, especially in the absence of homologous templates for protein structures.