Dipeptidyl peptidase-4 inhibitors: Anti-diabetic drugs with potential effects on cancer

Neuroendocrine tumors and diabetes mellitus: which treatment and which effect

Diabetes mellitus (DM) and neuroendocrine tumors (NET) can exert unfavorable effects on each other prognosis. In this narrative review, we evaluated the effects of NET therapies on glycemic control and DM management and the effects of anti-diabetic therapies on NET outcome and management. For this purpose, we searched the PubMed, Science Direct, and Google Scholar databases for studies reporting the effects of NET therapy on DM as well as the effect of DM therapy on NET. The majority of NET treatments appear to impair glycaemic control, both inducing hypoglycemic or, more commonly, hyperglycemia and even new-onset DM. However, glucose metabolism imbalance can be effectively managed by modulating anti-diabetic therapy and adopting an appropriate nutritional approach. On the other hand, the effects of anti-diabetic treatment, like insulin, sulfonylureas, thiazolidinediones, ipeptidyl-peptidase-4 inhibitors, Glucagon-like peptide-1 receptor agonists, and Sodium-glucose cotransporter-2 inhibitors on NET are unclear. Recently, metformin has been investigated in patients with gastroenteropancreatic NET resulting in improved progression free survival suggesting a potential antineoplastic role. Finally, the management of DM in patients with NET is of great clinical relevance to correctly perform radiological procedures and even more functional imaging procedures, as well as to optimize the therapy and avoid treatment withdrawal or discontinuation. In conclusion, understanding the mechanisms underlying therapy-induced DM and implementing appropriate monitoring and management strategies of DM are essential for optimizing NET patient outcome and quality of life.

Repurposing metabolic regulators: antidiabetic drugs as anticancer agents

Drug repurposing in cancer taps into the capabilities of existing drugs, initially designed for other ailments, as potential cancer treatments. It offers several advantages over traditional drug discovery, including reduced costs, reduced development timelines, and a lower risk of adverse effects. However, not all drug classes align seamlessly with a patient's condition or long-term usage. Hence, repurposing of chronically used drugs presents a more attractive option. On the other hand, metabolic reprogramming being an important hallmark of cancer paves the metabolic regulators as possible cancer therapeutics. This review emphasizes the importance and offers current insights into the repurposing of antidiabetic drugs, including metformin, sulfonylureas, sodium-glucose cotransporter 2 (SGLT2) inhibitors, dipeptidyl peptidase 4 (DPP-4) inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1RAs), thiazolidinediones (TZD), and α-glucosidase inhibitors, against various types of cancers. Antidiabetic drugs, regulating metabolic pathways have gained considerable attention in cancer research. The literature reveals a complex relationship between antidiabetic drugs and cancer risk. Among the antidiabetic drugs, metformin may possess anti-cancer properties, potentially reducing cancer cell proliferation, inducing apoptosis, and enhancing cancer cell sensitivity to chemotherapy. However, other antidiabetic drugs have revealed heterogeneous responses. Sulfonylureas and TZDs have not demonstrated consistent anti-cancer activity, while SGLT2 inhibitors and DPP-4 inhibitors have shown some potential benefits. GLP-1RAs have raised concerns due to possible associations with an increased risk of certain cancers. This review highlights that further research is warranted to elucidate the mechanisms underlying the potential anti-cancer effects of these drugs and to establish their efficacy and safety in clinical settings.

Pancreatitis and Pancreatic Cancer Risk Among Patients With Type 2 Diabetes Receiving Dipeptidyl Peptidase 4 Inhibitors: An Updated Meta-Analysis of Randomized Controlled Trials

PURPOSE

This meta-analysis sought to assess the relationship between dipeptidyl peptidase-4 inhibitors (DPP-4) and the risk of pancreatitis and pancreatic cancer by synthesizing data from randomized, controlled trials, in light of the conflicting findings from observational studies and previous meta-analyses.

METHODS

Cochrane, Embase, ClinicalTrials.gov, and PubMed databases that compared the use of DPP-4 inhibitors and that reported pancreatitis and pancreatic cancer events in patients with diabetes mellitus Type 2 (T2DM) were searched using specific terms. Studies were included if they satisfied the following inclusion criteria: They were randomized trials comparing DPP-4 inhibitors use in patients with T2DM; The study's duration was longer than 24 weeks; And they reported pancreatitis and pancreatic cancer events. Stata 15 MP was used to analyze the data, and odds ratios (OR) with 95% confidence intervals (CI) were used to represent the results.

FINDINGS

A total of 81,737 participants with T2DM were included in the analysis. The results showed that during a mean follow-up period of 24 to 520 weeks, The use of DPP-4 inhibitors was not associated with an increased risk of pancreatitis (Peto-OR 0.97; 95% CI: 0.74, 1.27) or pancreatic cancer (Peto-OR = 0.88; 95% CI: 0.59, 1.30).

IMPLICATIONS

Current evidence fails to validate a significant correlation between DPP-4 therapy and pancreatitis or pancreatic cancer. However, subgroup analyses showed that sitagliptin was associated with a significant reduction in pancreatitis risk compared to the control group; furthermore, when comparing different types of control medications, a significant decrease in pancreatic cancer risk was observed among DPP-4 users compared to GLP-1 users.

Discovery of Nine Dipeptidyl Peptidase-4 Inhibitors from Coptis chinensis Using Virtual Screening, Bioactivity Evaluation, and Binding Studies

The objective of this study was to identify multiple alkaloids in Coptis chinensis that demonstrate inhibitory activity against DPP-4 and systematically evaluate their activity and binding characteristics. A combined strategy that included molecular docking, a DPP-4 inhibition assay, surface plasmon resonance (SPR), and a molecular dynamics simulation technique was employed. The results showed that nine alkaloids in Coptis chinensis directly inhibited DPP-4, with IC50 values of 3.44-53.73 μM. SPR-based binding studies revealed that these alkaloids display rapid binding and dissociation characteristics when interacting with DPP-4, with KD values ranging from 8.11 to 29.97 μM. A molecular dynamics analysis revealed that equilibrium was rapidly reached by nine DPP-4-ligand systems with minimal fluctuations, while binding free energy calculations showed that the ∆Gbind values for the nine test compounds ranged from -31.84 to -16.06 kcal/mol. The most important forces for the binding of these alkaloids with DPP-4 are electrostatic interactions and van der Waals forces. Various important amino acid residues, such as Arg125, His126, Phe357, Arg358, and Tyr547, were involved in the inhibition of DPP-4 by the compounds, revealing a mechanistic basis for the further optimization of these alkaloids as DPP-4 inhibitors. This study confirmed nine alkaloids as direct inhibitors of DPP-4 and characterized their binding features, thereby providing a basis for further research and development on novel DPP-4 inhibitors.

Role of SGLT2 Inhibitors, DPP-4 Inhibitors, and Metformin in Pancreatic Cancer Prevention

Pancreatic carcinoma is a highly aggressive tumor that usually presents when it has already metastasized. Therapeutic options for cure remain scarce and rely on combination chemotherapy with limited sustainability. Diabetes is considered an important risk factor for the development of pancreatic cancer due to the production of proinflammatory cytokines, which result in increased cell proliferation. More than half of patients diagnosed with pancreatic cancer eventually develop diabetes due to the destruction of insulin-producing cells. The interlinkage of both diseases might identify a possible preventative strategy for reducing the incidence of pancreatic carcinoma. This study reviewed the recent literature on the association between pancreatic cancer risk and SGLT2 inhibitors, GLP-1 RA, DPP-4 inhibitors, and biguanides. There are mixed data regarding the relationship between GLP-1 RA and DPP-4 inhibitors and pancreatic cancer, with some trials suggesting that they might increase the risk. In contrast, studies have mostly revealed that SGLT2 inhibitors have an antiproliferative effect on various tumors, such as liver, pancreatic, prostate, bowel, lung, and breast carcinoma, which might be due to their mechanism of blockage of reabsorption of glucose by cells, lowering the amount of available glucose for the growth of tumor cells. Metformin, the first-line agent for diabetes, has also been shown to be associated with decreasing pancreatic cancer risk and improving prognosis in those who already have the disease. Dedicated trials are needed to further delineate the association of antidiabetic drugs with the risk of pancreatic cancer in the general population, as previous studies have mostly focused on diabetic patients.

Synthesis of β-Amino Carbonyl 6-(Aminomethyl)- and 6-(Hydroxymethyl)pyrazolopyrimidines for DPP-4 Inhibition Study

BACKGROUND

Type-2 diabetes is a chronic progressive metabolic disease resulting in severe vascular complications and mortality risk. Recently, DPP-4 inhibitors had been conceived as a favorable class of agents for the treatment of type 2 diabetes due to the minimal side effects.

METHODS

Sitagliptin is the first medicine approved for the DPP-4 inhibitor. Its structure involved three fragments: 2,4,5-triflorophenyl fragment pharmacophore, enantiomerically β-amino carbonyl linker, and tetrahydrotriazolopyridine. Herein, we are drawn to the possibility of substituting tetrahydrotriazolopyridine motif present in Sitagliptin with a series of new fused pyrazolopyrimidine bicyclic fragment to investigate potency and safety.

RESULTS

Two series of fused 6-(aminomethyl)pyrazolopyrimidine and 6-(hydroxymethyl) pyrazolopyrimidine derivatives containing β-amino ester or amide as linkers were successfully designed for the new DPP-4 inhibitors. Most fused 6-methylpyrazolopyrimidines were evaluated against DPP-4 inhibition and selectivity capacity. Based on research study, β-amino carbonyl fused 6-(hydroxymethyl)pyrazolopyrimidine possesses the significant DPP-4 inhibition (IC50 ≤ 59.8 nM) and presents similar with Sitagliptin (IC50 = 28 nM). Particularly, they had satisfactory selectivity over DPP-8 and DPP-9, except for QPP.

CONCLUSION

β-Amino esters and amides fused 6-(hydroxymethyl)pyrazolopyrimidine were developed as the new DPP-4 inhibitors. Those compounds with a methyl group or hydrogen in N-1 position and methyl substituted group in C-3 of pyrazolopyrimidine moiety showed better potent DPP-4 inhibition (IC50 = 21.4-59.8 nM). Furthermore, they had satisfactory selectivity over DPP-8 and DPP-9 Finally, the docking results revealed that compound 9n was stabilized at DPP-4 active site and would be a potential lead drug.

Pharmacotherapy of type 2 diabetes: An update and future directions

Type 2 diabetes (T2D) is a widely prevalent disease with substantial economic and social impact for which multiple conventional and novel pharmacotherapies are currently available; however, the landscape of T2D treatment is constantly changing as new therapies emerge and the understanding of currently available agents deepens. This review aims to provide an updated summary of the pharmacotherapeutic approach to T2D. Each class of agents is presented by mechanism of action, details of administration, side effect profile, cost, and use in certain populations including heart failure, non-alcoholic fatty liver disease, obesity, chronic kidney disease, and older individuals. We also review targets of novel therapeutic T2D agent development. Finally, we outline an up-to-date treatment approach that starts with identification of an individualized goal for glycemic control then selection, initiation, and further intensification of a personalized therapeutic plan for T2D.

The effect of metformin or dipeptidyl peptidase 4 inhibitors on clinical outcomes in metastatic non-small cell lung cancer treated with immune checkpoint inhibitors

BACKGROUND

Preclinical data have shown the immunomodulatory effects of metformin and dipeptidyl peptidase 4 (DPP4) inhibitors in patients with diabetes. However, its clinical impact remains unclear in lung cancer.

METHODS

Between 2017 and 2021, 466 patients received ICI monotherapy. Patients were categorized into concurrent (MET; metformin or combination of metformin and DPP4 inhibitor) and without concomitant (NMET; nonmetformin/DPP4 inhibitors) administration of metformin and DPP4 inhibitors groups at least 8 weeks before and during ICI therapy. The primary objectives were the objective response rate (ORR) and progression-free survival (PFS). The second objective was to evaluate the overall survival (OS) and the occurrence of immune-related adverse events (irAEs).

RESULTS

Among 466 patients, 89 (19.0%) and 377 (81%) were categorized into the MET and NMET groups, respectively. MET group had a significantly higher ORR (MET group: 24.7% vs. NMET group: 14.8%, p = 0.025) and longer PFS than those in the NMET group (MET group 5.1 month vs. NMET group 2.8 months, p = 0.018). After patients were stratified based on the prior line of therapy and PD L1 expression status, the PFS of the second-line therapy and PD L1 ≥50 was significantly higher in the MET than in the NMET group. The proportion of patients experiencing all-grade irAEs was numerically higher in the MET group (19.1%) than in the NMET group (14.3%), without statistical significance (p = 0.382).

CONCLUSIONS

Concurrent use of metformin and DPP4 inhibitors with ICIs significantly improved the clinical outcomes without increasing the incidence of irAEs in NSCLC.

Association of dipeptidyl peptidase IV polymorphism with clinicopathological characters of oral cancer

OBJECTIVE

To evaluate the associations between dipeptidyl peptidase IV (DPP4) single nucleotide polymorphism (SNP) and clinicopathological characters of oral cancer.

METHODS

Four loci of DPP4 SNPs (rs7608798 A/G, rs3788979 C/T, rs2268889 T/C, and rs6741949 G/C) were genotyped by using the TaqMan allelic discrimination in 1238 oral cancers patients and 1197 non-cancer individuals.

RESULTS

The percentage of DPP4 SNP rs2268889 TC+CC was significantly higher in the oral cancer participants compared to the control group (odds ratio (OR): 1.178, 95% confidence interval (CI): 1.004-1.382, P = 0.045). Among 1676 smokers, DPP4 polymorphisms carriers with betel quid chewing were found to have a 8.785- to 10.903-fold risk to have oral cancer compared to DPP4 wild-type carriers without betel quid chewing. Similar trend was found in individuals with alcohol consumption. Moreover, the oral cancer individuals without cigarette smoking history with at least 1 varied C allele of DPP4 rs2268889 had a significantly higher percentage of large tumor size with the wild-type TT homozygote (P= 0.011).

CONCLUSIONS

The DPP4 SNP may correlate to the development of oral cancer in those with cigarette smoking and alcohol consumption. Besides, the DPP4 SNP rs2268889 could relate to worse clinical course of oral cancer in non-smokers.

Decreased Mortality After Long-Term Treatment With Dipeptidyl Peptidase-4 Inhibitors: A Retrospective Study of U.S. Veterans With Type 2 Diabetes

OBJECTIVE

The prevalence of chronic kidney disease (CKD) in the United States is 13% of the general population. Among those with CKD, diabetic nephropathy is the leading cause of end-stage renal disease. This is a retrospective study examining the effect of long-term use of dipeptidyl peptidase-4 (DPP-4) inhibitors on all-cause mortality and progression of renal disease in the veteran population.

METHODS

Data was extracted using the Veterans Administration Informatics and Computing Infrastructure. A large cohort of veterans diagnosed with type 2 diabetes mellitus were used to identify patients on DPP-4 inhibitors and without DPP-4 inhibitors. Groups were compared to determine the effect of DPP-4 inhibitors on the progression of CKD and all-cause mortality. Data were analyzed using SAS.

RESULTS

Subjects in the treatment group (n = 40 558) had baseline variables (age, body mass index, race) similar to the control group (n = 40 558). Diabetes control improved in the treatment group (HgbA1c, 8.3% [67 mmol/mol] to 7.8% [62 mmol/mol]; P < .001) but not in the control group (HgbA1c, 7.4% [57 mmol/mol] to 7.3% [56 mmol/mol]). New diagnoses of heart failure and coronary artery bypass grafts were clinically significant (odds ratios = 0.66 and 0.52). No change in progression of CKD was seen in either group. All-cause mortality was reduced by 59%.

CONCLUSION

We conclude that DPP-4 inhibitors are associated with a significant reduction in all-cause mortality independent of glucose control, albeit with no clear cause, including obtainable cardiovascular outcomes. Our data is consistent with prior trials in that DPP-4 inhibitors did not show a significant change in serum creatinine or microalbuminuria.

Design, synthesis and biological evaluation of glycolamide, glycinamide, and β-amino carbonyl 1,2,4-triazole derivatives as DPP-4 inhibitors

Through modification of the skeleton of Sitagliptin and Vildagliptin, we successfully synthesized and built-up four series of 1,2,4-triazole derivatives, containing N,O-disubstituted glycolamide, N,N'-disubstituted glycinamide, β-amino ester, and β-amino amide as linkers, for the development of new dipeptidyl peptidase 4 (DPP-4) inhibitors. The synthetic strategy for glycolamides or glycinamides involved convenient two-steps reaction: functionalized transformation of 2-chloro-N-(2,4,5-triflurophenyl)acetamide 9 (hydroxylation or amination) and esterification or amidation of 1,2,4-triazole-3-carboxylic acid. On the other hand, the one-pot synthesis procedure, including substitution and deprotection, was developed for the preparation of β-amino carbonyl 1,2,4-triazoles from (1H-1,2,4-triazol-3-yl)methanol 12 or (1H-1,2,4-triazol-3-yl)methanamine 13 and Boc-(R)-3-amino-4-(2,4,5-trifluoro-phenyl)-butyric acid 14. All of glycolamides, glycinamides, and β-amino carbonyl 1,2,4-triazoles were also evaluated against DPP-4 inhibitory activity. Based on the SAR study of DPP-4 inhibitory capacity, β-amino ester 5n and β-amino amide 1,2,4-triazoles 6d and 6p possessed the significant inhibition of DPP-4 (IC₅₀ < 51.0 nM), particularly for compound 6d (IC₅₀ = 34.4 nM). The selectivity evaluation indicated compound 5n and 6p had excellent selectivity over QPP, DPP-8, and DPP-9. In addition, the docking results revealed compounds 5n and 6p provided stronger π-π stacking interaction with residue Phe357 than 1,5-disubstituted 1,2,4-triazole 6d and Sitagliptin 1. In summary, compounds 5n and 6p could be promising lead compounds for further development of DPP-4 inhibitor.

Incretin Hormones in Obesity and Related Cardiometabolic Disorders: The Clinical Perspective

The prevalence of obesity continues to grow rapidly worldwide, posing many public health challenges of the 21st century. Obese subjects are at major risk for serious diet-related noncommunicable diseases, including type 2 diabetes mellitus, cardiovascular disease, and non-alcoholic fatty liver disease. Understanding the mechanisms underlying obesity pathogenesis is needed for the development of effective treatment strategies. Dysregulation of incretin secretion and actions has been observed in obesity and related metabolic disorders; therefore, incretin-based therapies have been developed to provide new therapeutic options. Incretin mimetics present glucose-lowering properties, together with a reduction of appetite and food intake, resulting in weight loss. In this review, we describe the physiology of two known incretins—glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), and their role in obesity and related cardiometabolic disorders. We also focus on the available and incoming incretin-based medications that can be used in the treatment of the above-mentioned conditions.

Diabetic Cardiomyopathy: From Mechanism to Management in a Nutshell

Diabetic cardiomyopathy (DCM) is a significant complication of diabetes mellitus characterized by gradually failing heart with detrimental cardiac remodelings, such as fibrosis and diastolic and systolic dysfunction, which is not directly attributable to coronary artery disease. Insulin resistance and resulting hyperglycemia is the main trigger involved in the initiation of diabetic cardiomyopathy. There is a constellation of many pathophysiological events, such as lipotoxicity, oxidative stress, inflammation, inappropriate activation of the renin-angiotensin-aldosterone system, dysfunctional immune modulation promoting increased rate of cardiac cell injury, apoptosis, and necrosis, which ultimately culminates into interstitial fibrosis, cardiac stiffness, diastolic dysfunction, initially, and later systolic dysfunction too. These events finally lead to clinical heart failure of DCM. Herein, The pathophysiology of DCM is briefly discussed. Furthermore, potential therapeutic strategies currently used for DCM are also briefly mentioned.

Model Optimization and In Silico Analysis of Potential Dipeptidyl Peptidase IV Antagonists from GC-MS Identified Compounds in Nauclea latifolia Leaf Extracts

Dipeptidyl peptidase IV (DPP-IV) is a pharmacotherapeutic target in type 2 diabetes. Inhibitors of this enzyme constitute a new class of drugs used in the treatment and management of type 2 diabetes. In this study, phytocompounds in Nauclea latifolia (NL) leaf extracts, identified using gas chromatography–mass spectroscopy (GC-MS), were tested for potential antagonists of DPP-IV via in silico techniques. Phytocompounds present in N. latifolia aqueous (NLA) and ethanol (NLE) leaf extracts were identified using GC–MS. DPP-IV model optimization and molecular docking of the identified compounds/standard inhibitors in the binding pocket was simulated. Drug-likeness, pharmacokinetic and pharmacodynamic properties of promising docked leads were also predicted. Results showed the presence of 50 phytocompounds in NL extracts of which only 2-O-p-methylphenyl-1-thio-β-d-glucoside, 3-tosylsedoheptulose, 4-benzyloxy-6-hydroxymethyl-tetrahydropyran-2,3,5-triol and vitamin E exhibited comparable or better binding iGEMDOCK and AutoDock Vina scores than the clinically prescribed standards. These four compounds exhibited promising drug-likeness as well as absorption, distribution, metabolism, excretion and toxicity (ADMET) properties suggesting their candidature as novel leads for developing DPP-IV inhibitors.

Clinical Use of DPP-4 Inhibitors

DPP-4 inhibitors were introduced for the treatment of type 2 diabetes in 2006. They stimulate insulin secretion and inhibit glucagon secretion by elevating endogenous GLP-1 concentrations without an intrinsic hypoglycaemia risk. Their efficacy potential to lower HbA1c is in the range between 0.5 and 1.0% and their safety profile is favorable. DPP-4 inhibitors are body weight neutral and they have demonstrated cardiovascular safety. Most compounds can be used in impaired renal function. Guidelines suggest the additional use of DPP-4 inhibitors after metformin failure in patients that do not require antidiabetic therapy with proven cardiovascular benefit. Recently, DPP-4 inhibitors have increasingly replaced sulfonylureas as second line therapy after metformin failure and many metformin/DPP-4 inhibitor fixed dose combinations are available. In later stages of type 2 diabetes, DPP-4 inhibitors are also recommended in the guidelines in triple therapies with metformin and SGLT-2 inhibitors or with metformin and insulin. A treatment with DPP-4 inhibitors should be stopped when GLP-1 receptor agonists are used. DPP-4 inhibitors can be used as monotherapy when metformin is contraindicated or not tolerated. Some studies have shown value of initial metformin-DPP-4 inhibitor combination therapy in special populations. This article gives an overview on the clinical use of DPP-4 inhibitors.