Dipeptidyl peptidase 4 inhibitors as novel agents in improving survival in diabetic patients with colorectal cancer and lung cancer: A Surveillance Epidemiology and Endpoint Research Medicare study

Cancer biology in diabetes update: Focusing on antidiabetic drugs

The association of type 2 diabetes with certain cancer risk has been of great interest for years. However, the effect of diabetic medications on cancer development is not fully understood. Prospective clinical trials have not elucidated the long-term influence of hypoglycemic drugs on cancer incidence and the safety for cancer-bearing patients with diabetes, whereas numerous preclinical studies have shown that antidiabetic drugs could have an impact on carcinogenesis processes beyond the glycemic control effect. Because there is no evidence of the safety profile of antidiabetic agents on cancer biology, careful consideration would be required when prescribing any medicines to patients with diabetes and existing tumor. In this review, we discuss the potential influence of each diabetes therapy in cancer 'initiation', 'promotion' and 'progression'.

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.

Effect of DPP4/CD26 expression on SARS‑CoV‑2 susceptibility, immune response, adenosine (derivatives m62A and CD) regulations on patients with cancer and healthy individuals

The worldwide COVID‑19 pandemic was brought on by a new coronavirus (SARS Cov‑2). A marker/receptor called Dipeptidyl peptidase 4/CD26(DPP4/CD26) may be crucial in determining susceptibility to tumors and coronaviruses. However, the regulation of DPP4 in COVID‑invaded cancer patients and its role on small molecule compounds remain unclear. The present study used the Human Protein Atlas, Monaco, and Schmiedel databases to analyze the expression of DPP4 in human tissues and immune cells. The association between DPP4 expression and survival in various tumor tissues was compared using GEPIA 2. The DNMIVD database was used to analyze the correlation between DPP4 expression and promoter methylation in various tumors. On the cBioPortal network, the frequency of DPP4 DNA mutations in various cancers was analyzed. The correlation between DPP4 expression and immunomodulators was analyzed by TISIDB database. The inhibitory effects of cordycepin (CD), N6, N6‑dimethyladenosine (m⁶₂A) and adenosine (AD) on DPP4 in cancer cells were evaluated. DPP4 was mainly expressed in endocrine tissue, followed by gastrointestinal tract, female tissue (mainly in placenta), male tissue (mainly in prostate and seminal vesicle), proximal digestive tract, kidney, bladder, liver, gallbladder and respiratory system. In immune cells, DPP4 mRNA was mainly expressed in T cells, and its expression was upregulated in esophageal carcinoma, kidney renal papillary cell carcinoma (KIRP), liver hepatocellular carcinoma (LIHC), lung adenocarcinoma, pancreatic adenocarcinoma, prostate adenocarcinoma, stomach adenocarcinoma, thyroid carcinoma and thymoma. However, it was downregulated in breast invasive carcinoma, kidney chromophobe, lung squamous cell carcinoma and skin cutaneous melanoma. Thus, DPP4 is involved in viral invasion in most types of cancer. The expression of DPP4 could be inhibited by CD, m⁶₂A and AD in different tumor cells. Moreover, CD significantly inhibited the formation of GFP‑positive syncytial cells. In vivo experiments with AD injection further showed that AD significantly inhibited lymphocyte activating factor 3 expression. These drugs may have potential to treat COVID‑19 by targeting DPP4. Thus, DPP4 may be medically significant for SARS‑CoV‑2‑infected cancer patients, providing prospective novel targets and concepts for the creation of drugs against COVID‑19.

The many facets of CD26/dipeptidyl peptidase 4 and its inhibitors in disorders of the CNS - a critical overview

Dipeptidyl peptidase 4 is a serine protease that cleaves X-proline or X-alanine in the penultimate position. Natural substrates of the enzyme are glucagon-like peptide-1, glucagon inhibiting peptide, glucagon, neuropeptide Y, secretin, substance P, pituitary adenylate cyclase-activating polypeptide, endorphins, endomorphins, brain natriuretic peptide, beta-melanocyte stimulating hormone and amyloid peptides as well as some cytokines and chemokines. The enzyme is involved in the maintenance of blood glucose homeostasis and regulation of the immune system. It is expressed in many organs including the brain. DPP4 activity may be effectively depressed by DPP4 inhibitors. Apart from enzyme activity, DPP4 acts as a cell surface (co)receptor, associates with adeosine deaminase, interacts with extracellular matrix, and controls cell migration and differentiation. This review aims at revealing the impact of DPP4 and DPP4 inhibitors for several brain diseases (virus infections affecting the brain, tumours of the CNS, neurological and psychiatric disorders). Special emphasis is given to a possible involvement of DPP4 expressed in the brain.While prominent contributions of extracerebral DPP4 are evident for a majority of diseases discussed herein; a possible role of "brain" DPP4 is restricted to brain cancers and Alzheimer disease. For a number of diseases (Covid-19 infection, type 2 diabetes, Alzheimer disease, vascular dementia, Parkinson disease, Huntington disease, multiple sclerosis, stroke, and epilepsy), use of DPP4 inhibitors has been shown to have a disease-mitigating effect. However, these beneficial effects should mostly be attributed to the depression of "peripheral" DPP4, since currently used DPP4 inhibitors are not able to pass through the intact blood-brain barrier.

Dipeptidyl peptidase 4 (DPP-4) inhibitors and the risk of lung cancer: current evidence and future directions

INTRODUCTION

Recent evidence has linked long-term use of angiotensin converting enzyme (ACE) inhibitors with the risk of developing lung cancer by increasing levels of substance P (SP) and bradykinin in lung tissue. DPP-4 inhibitors, by virtue of their mechanism of action, may increase the level of SP and pose a similar risk of incident lung cancer. Concomitant use of DPP-4 inhibitors and ACE inhibitors may further exaggerate this plausible risk.

AREA COVERED

Here we discuss both direct and indirect evidence involving mechanisms by which DPP-4 inhibitors may increase the risk of lung cancer in treated patients. We highlight that increased levels of SP with DPP-4 inhibitor monotherapy and raised levels of both SP and bradykinin with add-on ACE inhibitor therapy may further enhance this risk.

EXPERT OPINION

DPP-4 inhibitors are prescribed in type-2 diabetes mellitus patients with or without cardiovascular disease. When used together, ACE inhibitors and DPP-4 inhibitors may act synergistically and further amplify the lung cancer risk. Consequently, physicians should consider this plausible association while prescribing them concomitantly especially in high-risk individuals. Well-planned research studies are required to assess the association of DPP-4 inhibitors with lung cancer and other adverse effects linked to increased levels of SP and bradykinin.

Crosstalk between incretin hormones, Th17 and Treg cells in inflammatory diseases

Intestinal epithelial cells constantly crosstalk with the gut microbiota and immune cells of the gut lamina propria. Enteroendocrine cells, secrete hormones, such as incretin hormones, which participate in host physiological events, such as stimulating insulin secretion, satiety, and glucose homeostasis. Interestingly, evidence suggests that the incretin pathway may influence immune cell activation. Consequently, drugs targeting the incretin hormone signaling pathway may ameliorate inflammatory diseases such as inflammatory bowel diseases, cancer, and autoimmune diseases. In this review, we discuss how these hormones may modulate two subsets of CD4 + T cells, the regulatory T cells (Treg)/Th17 axis important for gut homeostasis: thus, preventing the development and progression of inflammatory diseases. We also summarize the main experimental and clinical findings using drugs targeting the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide (GLP-1) signaling pathways and their great impact on conditions in which the Treg/Th17 axis is disturbed such as inflammatory diseases and cancer. Understanding the role of incretin stimulation in immune cell activation and function, might contribute to new therapeutic designs for the treatment of inflammatory diseases, autoimmunity, and tumors.

Neutrophil extracellular traps (NETs) reduce the diffusion of doxorubicin which may attenuate its ability to induce apoptosis of ovarian cancer cells

Purpose

Although neutrophil extracellular traps (NETs) are present in various tumors, their roles in tumor biology have not been clarified yet. In this study, we examined how NETs affect the pharmacokinetics and effects of doxorubicin (DOX).

Methods

NETs were generated by neutrophils stimulated with phorbol 12-myristate 13-acetate (PMA) or lipopolysaccharide (LPS). DOX was added to NETs and their distribution was observed under fluorescein microscopy, and the diffusion of DOX through 3 μM pores from lower to upper chambers was evaluated with a fluorescence-based assay. Ovarian cancer cells, KOC-2S and SKOV3, were embedded in collagen gel droplets and cultured in 3D way and their apoptosis was examined with flow cytometry.

Results

DOX was mostly co-localized with NETs. The transfer of DOX to upper chambers increased over time, which was significantly decreased by the presence of neutrophils stimulated with PMA or LPS in the lower chamber. DOX outside of the gel increased the rates of annexin V (+) apoptotic cells, which were significantly reduced by the addition of LPS-stimulated neutrophils in media both in KOC-2S and SKOV3. The reduced diffusion and apoptosis were mostly restored by the destruction of the NETs structure with 1000 u/ml DNAse I.

Conclusion

NETs efficiently trap and inhibit the diffusion of DOX which may attenuate its ability to induce apoptosis of ovarian cancer cells. Degradation of NETs with DNAse I may augment the response of ovarian cancer to DOX.

•

Doxorubicin is efficiently trapped by neutrophil extracellular traps (NETs).

•

NETs suppress diffusion of doxorubicin through micro-pores and infiltration into resected tumor.

•

NETs suppress doxorubicin-induced apoptosis of tumor cells in 3-D culture.

•

DNAse may augment the effect of anti-cancer drugs by modulating pharmacokinetics.

Does DPP-IV Inhibition Offer New Avenues for Therapeutic Intervention in Malignant Disease?

Simple Summary

There is growing interest in identifying the effects of antidiabetic agents on cancer risk, progression, and anti-cancer treatment due to the long-term use of these medications and the inherently increased risk of malignancies in diabetic patients. Tumor development and progression are affected by multiple mediators in the tumor microenvironment, several of which may be proteolytically modified by the multifunctional protease dipeptidyl peptidase-IV (DPP-IV, CD26). Currently, low-molecular-weight DPP-IV inhibitors (gliptins) are used in patients with type 2 diabetes based on the observation that DPP-IV inhibition enhances insulin secretion by increasing the bioavailability of incretins. However, the DPP-IV-mediated cleavage of other biopeptides and chemokines is also prevented by gliptins. The potential utility of gliptins in other areas of medicine, including cancer, is therefore being evaluated. Here, we critically review the existing evidence on the role of DPP-IV inhibitors in cancer pathogenesis, their potential to be used in anti-cancer treatment, and the possible perils associated with this approach.

Abstract

Dipeptidyl peptidase IV (DPP-IV, CD26) is frequently dysregulated in cancer and plays an important role in regulating multiple bioactive peptides with the potential to influence cancer progression and the recruitment of immune cells. Therefore, it represents a potential contributing factor to cancer pathogenesis and an attractive therapeutic target. Specific DPP-IV inhibitors (gliptins) are currently used in patients with type 2 diabetes mellitus to promote insulin secretion by prolonging the activity of the incretins glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). Nevertheless, the modulation of the bioavailability and function of other DPP-IV substrates, including chemokines, raises the possibility that the use of these orally administered drugs with favorable side-effect profiles might be extended beyond the treatment of hyperglycemia. In this review, we critically examine the possible utilization of DPP-IV inhibition in cancer prevention and various aspects of cancer treatment and discuss the potential perils associated with the inhibition of DPP-IV in cancer. The current literature is summarized regarding the possible chemopreventive and cytotoxic effects of gliptins and their potential utility in modulating the anti-tumor immune response, enhancing hematopoietic stem cell transplantation, preventing acute graft-versus-host disease, and alleviating the side-effects of conventional anti-tumor treatments.

The impact of oral hypoglycemics and statins on outcomes in myelodysplastic syndromes

Observational studies suggest an anti-neoplastic effect associated with statins, metformin, and dipeptidyl peptidase-4 inhibitors (DPP4i), while sulfonylureas may have a neutral or detrimental effect. We linked the Ontario subset of a prospective Canadian myelodysplastic syndromes (MDS) registry with provincial administrative databases. We assessed the impact of statin/oral hypoglycemic medication exposure on overall survival (OS) using Cox regression analysis, controlling for comorbidities and sociodemographic factors. Five hundred thirty-three patients aged ≥ 66 years were included: 49.3% used statins, 18.9% used metformin, 9.0% used sulfonylureas, and 6.4% used DPP4i. Three hundred ninety-five patients were lower-risk based on the International Prognostic Scoring System. On univariate analysis, we identified a marginal improvement in OS in the lower-risk group using DPP4i (HR 0.98, 95% CI 0.95-1.00, P = 0.05), while there was no impact on mortality for higher-risk DPP4i users (HR 1.03, CI 0.99-1.07, P = 0.21). There was no mortality difference for statins (HR 1.00, CI 1.00-1.01, P = 0.93), metformin (HR 1.00, CI 0.99-1.01, P = 0.81), or sulfonylureas (HR 1.00, CI 0.99-1.02, P = 0.43) in the entire cohort, as well as when stratified into lower/higher-risk groups. On multivariable analysis in the lower-risk group, there was no association between DPP4i and OS (HR 0.98, CI 0.95-1.00, P = 0.06). Prospective studies with larger cohorts of patients and longer follow-up are required to further study the impact of DPP4i in MDS.

Differential Risk of Cancer Associated with Glucagon-like Peptide-1 Receptor Agonists: Analysis of Real-world Databases

BACKGROUND

Glucagon-like peptide 1 receptor agonists (GLP1Ra) are commonly used in type 2 diabetes mellitus (T2DM). However, differential risk of various cancers among GLP1Ra recipients is unknown.

METHODS

We inquired an aggregated electronic health record database, Explorys, and compared the adjusted odds ratio (aOR) of cancers between GLP1Ra and metformin users. Findings were validated in the FDA Adverse Event Reporting System (FDA FAERS).

RESULTS

From 1/2005 to 6/2019, we identified 619 340 and 64 230 patients in the metformin and GLP1Ra group, respectively. Within 5 years of starting antidiabetic medications, GLP1Ra was associated with significantly lower incident risk of prostate (aOR 0.81, p = .03), lung (aOR 0.81, p = .05), and colon cancer (aOR 0.85, p = .03), while the risk of thyroid cancer was significantly higher (aOR 1.65, p < .01). Similar findings were seen in the FDA FAERS database, where GLP1Ra was associated with lower risk of prostate (aOR 0.72, p = .08), lung (aOR 0.52, p < .01), colon cancer (aOR 0.82, p = .31), and higher risk of thyroid cancer (aOR 4.33, p < .01). In addition, with longer duration of GLP1Ra use, the risk of prostate, lung, and colon cancer further decreased, suggesting an exposure duration-response relationship.

CONCLUSIONS

GLP1Ra is associated with lower risks of prostate, lung, and colon cancer, but higher risk of thyroid cancer.

Validating Cell Surface Proteases as Drug Targets for Cancer Therapy: What Do We Know, and Where Do We Go?

Simple Summary

Cell surface proteases (so-called ectoproteases) are associated with cancer, and their targeting may confer valuable options for the improvement of cancer treatment outcome. Over the past 20 years, the permanent development of a multitude of inhibitors against several ectoproteases (including DPP4, FAP, APN, ADAM17, MMP2, and MMP9) has made it into clinical evaluation in haematological and solid tumours. Among them, a few show some efficacy, albeit limited, to cure cancer in the near future. This Review summarizes the efforts thus far undertaken in the development of ectoprotease inhibitors and highlights new directions for targeting ectoproteases as an additional weapon in the fight against cancer.

Abstract

Cell surface proteases (also known as ectoproteases) are transmembrane and membrane-bound enzymes involved in various physiological and pathological processes. Several members, most notably dipeptidyl peptidase 4 (DPP4/CD26) and its related family member fibroblast activation protein (FAP), aminopeptidase N (APN/CD13), a disintegrin and metalloprotease 17 (ADAM17/TACE), and matrix metalloproteinases (MMPs) MMP2 and MMP9, are often overexpressed in cancers and have been associated with tumour dysfunction. With multifaceted actions, these ectoproteases have been validated as therapeutic targets for cancer. Numerous inhibitors have been developed to target these enzymes, attempting to control their enzymatic activity. Even though clinical trials with these compounds did not show the expected results in most cases, the field of ectoprotease inhibitors is growing. This review summarizes the current knowledge on this subject and highlights the recent development of more effective and selective drugs targeting ectoproteases among which small molecular weight inhibitors, peptide conjugates, prodrugs, or monoclonal antibodies (mAbs) and derivatives. These promising avenues have the potential to deliver novel therapeutic strategies in the treatment of cancers.

CD26 Induces Colorectal Cancer Angiogenesis and Metastasis through CAV1/MMP1 Signaling

CD26 has been reported as a marker for colorectal cancer stem cells endowed with tumor-initiating properties and capable of colorectal cancer (CRC) metastasis. In this study, we investigated the functional effect of CD26 on CRC angiogenesis and metastasis, and the potential underlying mechanism. The functional effects of CD26 overexpression or repression were determined by a wound healing experiment, and cell migration and invasion assays in vitro and in mouse models. Differentially expressed genes regulated by CD26 were identified by genome-wide mRNA expression array and validated by quantitative PCR. CD26 functionally regulated CRC cell migration and invasion in vitro and angiogenesis and metastasis in vivo. Genome-wide mRNA expression array and qPCR showed that MMP1 was up-regulated in CD26+ subpopulation, and a subsequent experiment demonstrated the regulatory effect of CD26 on MMP1 in CRC cell lines with CD26 repression or overexpression. Furthermore, overexpression of CAV1 abrogated the CD26-regulated MMP1 induction in CRC cell lines. This study demonstrated the functional roles of CD26 in inducing CRC migration, invasion, angiogenesis and metastasis and identified the potential involvement of MMP1 and CAV1 in such process. CD26 is an attractive therapeutic target for combating tumor progression to improve the prognosis of CRC patients.

The Roles of Dipeptidyl Peptidase 4 (DPP4) and DPP4 Inhibitors in Different Lung Diseases: New Evidence

CD26/Dipeptidyl peptidase 4 (DPP4) is a type II transmembrane glycoprotein that is widely expressed in various organs and cells. It can also exist in body fluids in a soluble form. DPP4 participates in various physiological and pathological processes by regulating energy metabolism, inflammation, and immune function. DPP4 inhibitors have been approved by the Food and Drug Administration (FDA) for the treatment of type 2 diabetes mellitus. More evidence has shown the role of DPP4 in the pathogenesis of lung diseases, since it is highly expressed in the lung parenchyma and the surface of the epithelium, vascular endothelium, and fibroblasts of human bronchi. It is a potential biomarker and therapeutic target for various lung diseases. During the coronavirus disease-19 (COVID-19) global pandemic, DPP4 was found to be an important marker that may play a significant role in disease progression. Some clinical trials on DPP4 inhibitors in COVID-19 are ongoing. DPP4 also affects other infectious respiratory diseases such as Middle East respiratory syndrome and non-infectious lung diseases such as pulmonary fibrosis, lung cancer, chronic obstructive pulmonary disease (COPD), and asthma. This review aims to summarize the roles of DPP4 and its inhibitors in infectious lung diseases and non-infectious diseases to provide new insights for clinical physicians.

The Serine Protease CD26/DPP4 in Non-Transformed and Malignant T Cells

Simple Summary

The transmembrane serine protease CD26/Dipeptidylpeptidase 4 modulates T-cell activation, proliferation, and effector function. Due to their remarkable tumoricidal properties CD26-positive T cells are considered promising candidates for T cell-based immunotherapies while in cutaneous T cell lymphoma CD26/DPP4 expression patterns are established markers for diagnosis and possibly prognosis. With a focus on T cells, we review current knowledge on the regulation of CD26/DPP4 expression and release, its implication in T-cell effector function and the suitability CD26/DPP4 as a diagnostic and/or prognostic factor in T-cell malignancies.

Abstract

CD26/Dipeptidylpeptidase 4 is a transmembrane serine protease that cleaves off N-terminal dipeptides. CD26/DPP4 is expressed on several immune cell types including T and NK cells, dendritic cells, and activated B cells. A catalytically active soluble form of CD26/DPP4 can be released from the plasma membrane. Given its wide array of substrates and interaction partners CD26/DPP4 has been implicated in numerous biological processes and effects can be dependent or independent of its enzymatic activity and are exerted by the transmembrane protein and/or the soluble form. CD26/DPP4 has been implicated in the modulation of T-cell activation and proliferation and CD26/DPP4-positive T cells are characterized by remarkable anti-tumor properties rendering them interesting candidates for T cell-based immunotherapies. Moreover, especially in cutaneous T-cell lymphoma CD26/DPP4 expression patterns emerged as an established marker for diagnosis and treatment monitoring. Surprisingly, besides a profound knowledge on substrates, interaction partners, and associated signal transduction pathways, the precise role of CD26/DPP4 for T cell-based immune responses is only partially understood.

Dipeptidyl Peptidase (DPP)-4 Inhibitor Impairs the Outcomes of Patients with Type 2 Diabetes Mellitus After Curative Resection for Colorectal Cancer

Dipeptidyl peptidase IV inhibitor (DPP-4i) has been shown to act either as a promoter or as a suppressor for cancer. Although epidemiologic studies suggest that DPP-4i does not correlate with the development of malignancies, its effects on cancer metastases are controversial. We evaluated the impact of DPP-4i on postoperative outcomes of the diabetic patients with colorectal cancer and microscopic features of the resected tumors. In 260 consecutive patients with type 2 diabetes mellitus (T2DM) who underwent curative resection of colorectal cancer, the correlation between DPP-4i use and prognosis was retrospectively examined. Expression of Zeb1 on tumor cells and density of infiltrating immune cells were quantitatively evaluated with multicolor IHC in 40 tumors from DPP-4i users, 40 tumors from propensity score-matched users, and 40 tumors from nonusers. Postoperative disease-free survival (DFS) was significantly lower in 135 patients treated with DPP-4i compared with 125 nontreated patients [5-year DFS, 73.7% vs. 87.4%; HR, 1.98; 95% confidence interval (CI), 1.05-3.71; P = 0.035]. IHC revealed that the number of Zeb1⁺ tumor cells increased in tumors from DPP-4i-treated patients than tumors from nonusers (P < 0.01). The densities of CD3⁺ and CD8⁺ T cells were significantly lower in tumors from DPP-4i users (P < 0.01) with decreased density of tertiary lymphoid structures (P < 0.001). However, the density of M2-type tumor-associated macrophages with CD68⁺ CD163⁺ phenotypes was significantly higher (P < 0.01) in tumors from DPP-4i users. Exposure of colorectal cancer to DPP-4i may accelerate epithelial-to-mesenchymal transition (EMT) creating a tumor-permissive immune microenvironment, which might impair the outcomes of the patients with colorectal cancer and T2DM.

Significance

DPP-4i has been shown to enhance the antitumor effects of immunotherapy. However, we found that DPP-4i significantly impairs the outcomes of patients with colorectal cancer who underwent curative resection, possibly through acceleration of EMT and creation of a tumor-permissive immune microenvironment. This suggests that DPP-4i must be used with caution until its safety is fully confirmed by further studies of the mechanistic effects on existing cancers in humans.

Sodium-Glucose Co-Transporter 2 Inhibitors May Change the Development of Urinary Tract and Hematological Malignancies as Compared With Dipeptidyl Peptidase-4 Inhibitors: Data of the Post-Hoc Analysis of a Nationwide Study

Background

In diabetes mellitus, during the last years, cancer became of equivalent importance as a cardiovascular disease in terms of mortality. In an earlier study, we have analyzed data of the National Health Insurance Fund (NHIF) of Hungary with regards all patients treated with sodium-glucose co-transporter 2 (SGLT2) inhibitors (SGLT2is) vs. those treated with dipeptidyl peptidase-4 (DPP-4) inhibitors (DPP-4is) in a given timeframe. In propensity score-matched groups of SGLT2i- vs. DPP-4i-treated patients, we found a lower incidence of cancer in general. In this post-hoc analysis, we aimed to obtain data on the incidence of site-specific cancer.

Patients and Methods

All patients starting an SGLT2i or a DPP-4i between 2014 and 2017 in Hungary were included; the two groups (SGLT2i vs. DPP-4i) were matched for 54 clinical and demographical parameters. The follow-up period was 639 vs. 696 days, respectively. Patients with a letter “C” International Classification of Diseases, 10th Revision (ICD-10) code have been chosen, and those with a known malignancy within a year before the onset of the study have been excluded from the analysis.

Results

We found a lower risk of urinary tract [HR 0.50 (95% CI: 0.32–0.79) p = 0.0027] and hematological malignancies [HR 0.50 (95% CI: 0.28–0.88) p = 0.0174] in patients treated with SGLT2i vs. those on DPP-4i. Risk of other types of cancer (including lung and larynx, lower gastrointestinal (GI) tract, rectum, pancreas, non-melanoma skin cancers, breast, or prostate) did not differ significantly between the two groups. When plotting absolute risk difference against follow-up time, an early divergence of curves was found in case of prostate, urinary tract, and hematological malignancies, whereas late divergence can be seen in case of cancers of the lung and larynx, the lower GI tract, and the breast.

Conclusions

Urinary tract and hematological malignancies were less frequent in patients treated with SGLT2i vs. DPP-4i. An early vs. late divergence could be observed for different cancer types, which deserves further studies.

Dipeptidyl Peptidase Inhibition Enhances CD8 T Cell Recruitment and Activates Intrahepatic Inflammasome in a Murine Model of Hepatocellular Carcinoma

Simple Summary

This study reported, for the first time, on the expression and activity of the dipeptidyl peptidase 4 (DPP4) family during the development of hepatocellular carcinoma (HCC). We also demonstrated that the pan-DPP inhibitory compound ARI-4175 significantly reduced the number of macroscopic liver nodules in a mouse HCC model. ARI-4175 increased intrahepatic inflammatory cell infiltration, CD8⁺ T cell numbers and caspase-1-mediated inflammasome activation in the HCC-bearing liver. Thus, this study provides promising data on the efficacy of ARI-4175 in the treatment of early-stage HCC. Targeting the DPP4 family may be a novel and effective approach to promote anti-tumour immunity in HCC via caspase-1 activation.

Abstract

The mRNA expression of the dipeptidyl peptidase 4 (DPP4) gene family is highly upregulated in human hepatocellular carcinoma (HCC) and is associated with poor survival in HCC patients. Compounds that inhibit the DPP4 enzyme family, such as talabostat and ARI-4175, can mediate tumour regression by immune-mediated mechanisms that are believed to include NLRP1 activation. This study investigated the expression and activity of the DPP4 family during the development of HCC and evaluated the efficacy of ARI-4175 in the treatment of early HCC in mice. This first report on this enzyme family in HCC-bearing mice showed DPP9 upregulation in HCC, whereas intrahepatic DPP8/9 and DPP4 enzyme activity levels decreased with age. We demonstrated that ARI-4175 significantly lowered the total number of macroscopic liver nodules in these mice. In addition, ARI-4175 increased intrahepatic inflammatory cell infiltration, including CD8⁺ T cell numbers, into the HCC-bearing livers. Furthermore, ARI-4175 activated a critical component of the inflammasome pathway, caspase-1, in these HCC-bearing livers. This is the first evidence of caspase-1 activation by a pan-DPP inhibitor in the liver. Our data suggest that targeting the DPP4 enzyme family may be a novel and effective approach to promote anti-tumour immunity in HCC via caspase-1 activation.

Chromatin Remodeling of Colorectal Cancer Liver Metastasis is Mediated by an HGF-PU.1-DPP4 Axis

Colorectal cancer (CRC) metastasizes mainly to the liver, which accounts for the majority of CRC-related deaths. Here it is shown that metastatic cells undergo specific chromatin remodeling in the liver. Hepatic growth factor (HGF) induces phosphorylation of PU.1, a pioneer factor, which in turn binds and opens chromatin regions of downstream effector genes. PU.1 increases histone acetylation at the DPP4 locus. Precise epigenetic silencing by CRISPR/dCas9KRAB or CRISPR/dCas9HDAC revealed that individual PU.1-remodeled regulatory elements collectively modulate DPP4 expression and liver metastasis growth. Genetic silencing or pharmacological inhibition of each factor along this chromatin remodeling axis strongly suppressed liver metastasis. Therefore, microenvironment-induced epimutation is an important mechanism for metastatic tumor cells to grow in their new niche. This study presents a potential strategy to target chromatin remodeling in metastatic cancer and the promise of repurposing drugs to treat metastasis.

The Role of Post-Translational Modifications of Chemokines by CD26 in Cancer

Chemokines are a large family of small chemotactic cytokines that fulfill a central function in cancer. Both tumor-promoting and -impeding roles have been ascribed to chemokines, which they exert in a direct or indirect manner. An important post-translational modification that regulates chemokine activity is the NH₂-terminal truncation by peptidases. CD26 is a dipeptidyl peptidase (DPPIV), which typically clips a NH₂-terminal dipeptide from the chemokine. With a certain degree of selectivity in terms of chemokine substrate, CD26 only recognizes chemokines with a penultimate proline or alanine. Chemokines can be protected against CD26 recognition by specific amino acid residues within the chemokine structure, by oligomerization or by binding to cellular glycosaminoglycans (GAGs). Upon truncation, the binding affinity for receptors and GAGs is altered, which influences chemokine function. The consequences of CD26-mediated clipping vary, as unchanged, enhanced, and reduced activities are reported. In tumors, CD26 most likely has the most profound effect on CXCL12 and the interferon (IFN)-inducible CXCR3 ligands, which are converted into receptor antagonists upon truncation. Depending on the tumor type, expression of CD26 is upregulated or downregulated and often results in the preferential generation of the chemokine isoform most favorable for tumor progression. Considering the tight relationship between chemokine sequence and chemokine binding specificity, molecules with the appropriate characteristics can be chemically engineered to provide innovative therapeutic strategies in a cancer setting.

Antidiabetic drugs and the risk of cancer: beneficial, neutral, or detrimental?

The prevalence of diabetes mellitus is rapidly rising, especially in low- and middle-income countries. Also, early-onset diabetes is on the rise, and millions of individuals have to be on antidiabetic medications for a prolonged period. Therefore, more people are getting exposed to the adverse effects of antidiabetic medications.

Cancer is among the top ranking causes of death worldwide. Researches are still ongoing to understand the etiologies, precipitants, risk factors, correlates, and predictors of cancers. Diabetes mellitus is associated with various cancers, as extensively documented in the literature. There are conflicting reports about the association between antidiabetic drugs and cancer. This is even of crucial importance, considering that the prevalence of diabetes is rising.

Insulin glargine is reported to be associated with cancers, but clinical trials have not confirmed this. Metformin is largely believed to be beneficial in oncologic practice. Glibenclamide is reported to reduce tumor growth. The association between pioglitazone and bladder cancer is still an area for further research. Meglitinides have also been associated with cancers. Incretin-based therapy and the α-glucosidase inhibitors appear to have beneficial effects on cancers.

There is still a need for randomized multicentric clinical trials to further substantiate and clarify reports from epidemiological studies. Further in vitro studies will also be necessary to characterize the interaction of these pharmacological agents with other molecules in the body.

Repurposing DPP-4 Inhibitors for Colorectal Cancer: A Retrospective and Single Center Study

Simple Summary

Colorectal cancer is one of the most common causes and the leading cause of cancer deaths worldwide. Its poor prognosis highlights the urgent need for more effective treatments. Repurposing approved drugs is a promising strategy as preclinical screenings can be minimized. The aim of our retrospective study was to investigate the potential of Dipeptidyl-peptidase 4 (DPP4)-inhibitors, which are safe Food and Drug Association (FDA)-approved drugs for treating diabetes, in treating CRC patients. Our findings conclude that CRC patients with diabetes and treated with DPP4-inhibitors in our hospital during 2006–2015, their 5-year prognosis following curative resection was significantly better than those treated with metformin. We further showed that their prognosis was associated with immune cell population features that associated with better prognosis, and immune cell profile is a biomarker for predicting the prognosis of DPP4-inhibitors treated CRC patients.

Abstract

Background: There have been studies reporting the crucial roles of Dipeptidyl-peptidase 4 (DPP4) in colorectal cancer (CRC) initiation and progression, whereas DPP4-inhibitors are safe Food and Drug Association (FDA)-approved drugs for treating diabetes. This study aims to investigate the association between DPP4-inhibitor treatment and the prognosis of CRC patients. Methods: Clinical data of CRC patients with diabetes and the prescription of DPP4-inhibitors who had undergone curative surgery in our hospital between January 2006 and December 2015 were retrieved. Their survival data and immune cell population in circulatory blood were compared to those treated with metformin. Results: The DPP4-inhibitor patient group showed a significantly better 5-year disease-free survival (median DFS = 1733 days, 95% CI = 1596 to 1870 days) when compared to the metformin group (p = 0.030, median DFS = 1382 days, 95% CI = 1246 to 1518 days). 33 out of the 92 patients in the metformin group showed recurrence whereas only 3 of the 26 patients in the DPP4-inhibitor group showed recurrence (p = 0.033). Cox regression analysis demonstrated that DPP4-inhibitor application is a favorable factor associated with a lower risk of recurrence (Hazard ratio = 0.200, p = 0.035). Furthermore, our results suggested that the immune cell profile of CRC patients is a potential biomarker for response to DPP4-inhibitor treatment. Conclusion: This study demonstrated the association of DPP4-inhibitor treatment with a better prognosis of CRC patients.

CD26/DPP-4: Type 2 Diabetes Drug Target with Potential Influence on Cancer Biology

Simple Summary

Dipeptidyl peptidase (DPP)-4 inhibitor is widely used for type 2 diabetes. Although DPP-4/CD26 has been recognized as both a suppressor and inducer in tumor biology due to its various functions, how DPP-4 inhibitor affects cancer progression in diabetic patients is still unknown. The aim of this review is to summarize one unfavorable aspect of DPP-4 inhibitor in cancer-bearing diabetic patients.

Abstract

DPP-4/CD26, a membrane-bound glycoprotein, is ubiquitously expressed and has diverse biological functions. Because of its enzymatic action, such as the degradation of incretin hormones, DPP-4/CD26 is recognized as the significant therapeutic target for type 2 diabetes (T2DM); DPP-4 inhibitors have been used as an anti-diabetic agent for a decade. The safety profile of DPP-4 inhibitors for a cardiovascular event in T2DM patients has been widely analyzed; however, a clear association between DPP-4 inhibitors and tumor biology is not yet established. Previous preclinical studies reported that DPP-4 suppression would impact tumor progression processes. With regard to this finding, we have shown that the DPP-4 inhibitor induces breast cancer metastasis and chemoresistance via an increase in its substrate C-X-C motif chemokine 12, and the consequent induction of epithelial-mesenchymal transition in the tumor. DPP-4/CD26 plays diverse pivotal roles beyond blood glucose control; thus, DPP-4 inhibitors can potentially impact cancer-bearing T2DM patients either favorably or unfavorably. In this review, we primarily focus on the possible undesirable effect of DPP-4 inhibition on tumor biology. Clinicians should note that the safety of DPP-4 inhibitors for diabetic patients with an existing cancer is an unresolved issue, and further mechanistic analysis is essential in this field.

A Multi-Center Retrospective Analysis Examining the Effect of Dipeptidyl Peptidase-4 Inhibitors on Progression-Free Survival in Patients With Prostate Cancer

Background

Cluster of differentiation 26/dipeptidyl peptidase-4 (DPP4) is a cell surface glycoprotein with multifaceted roles, including immune regulation, glucose metabolism, and tumorigenesis. Recent literature has identified DPP4 inhibitors to improve survival in diabetic patients with prostate cancer. DPP4 inhibitors have been proposed to play a role in prostate cancer, as DPP4 is found at higher levels in malignant prostate tissue compared to benign and correlates with PSA levels and cancer stage. In this multi-center retrospective study, we aim to define the effects of DPP4 inhibitors on progression-free survival (PFS) in diabetic patients with advanced-stage prostate cancer.

Methodology

We performed a retrospective analysis of 161 patients with diabetes and advanced-stage (III or IV) prostate cancer at the University of Florida Health Cancer Center and Moffitt Cancer Center. Our cohort included 120 patients on metformin (control group) and 41 on a DPP4 inhibitor (study group).

Results

No significant difference in progression of prostate cancer was identified between those on DPP4 inhibitors versus metformin (hazard ratio [HR]: 1.01; 95% confidence interval [CI]: 0.64-1.61; p = 0.955). Median time to progression was 3.5 years (range: 2.4-4.6 years).

Conclusions

Despite prior literature indicating survival benefit of DPP4 inhibitors in prostate cancer, our study did not identify a statistically significant improvement of PFS in diabetic patients with advanced prostate cancer. Additional analysis with larger sample sizes and prospective investigation with study of tumor microenvironment are needed to evaluate clinical impact and potential survival benefit of DPP4 inhibitors in prostate cancer.

Attenuation of diethyl nitrosamine-induced hepatocellular carcinoma by taxifolin and/or alogliptin: The interplay between toll-like receptor 4, transforming growth factor beta-1, and apoptosis

Hepatocellular carcinoma (HCC) is the most common form of liver malignancies worldwide. Alogliptin is an anti-diabetic that may have effective anticancer properties against many types of malignancies. Taxifolin is a flavonoid that has potent antioxidant, and anti-inflammatory properties. The objective of this study was to explore the impact of alogliptin and/or taxifolin on diethyl nitrosamine-induced HCC in rats. One hundred male Wistar rats were divided into five equal groups as follows: Control; HCC; HCC + Alogliptin; HCC + Taxifolin; and HCC + Alogliptin + Taxifolin group. The survival rate, liver function tests, tissue antioxidant enzymes, malondialdehyde (MDA), nuclear factor (erythroid derived 2)-like 2 (Nrf2), transforming growth factor beta 1 (TGF-β1), interleukin 1 alpha (IL-1α), and toll-like receptor 4 (TLR4) were measured. Also, hepatic caspase 3, caspase 9, beclin-1, and c-Jun NH2-terminal kinase (JNK) in addition to serum alpha-fetoprotein (AFP) and α-L-Fucosidase (AFU) were assessed. Specimens of the liver were subjected to histopathological examination. Alogliptin and/or taxifolin induced significant improvement of liver function tests with significant increase in the survival rate, tissue antioxidant enzymes, Nrf2, caspase 3, caspase 9, Beclin-1 and JNK activities associated with significant decrease in serum AFP and AFU, tissue MDA, TGF-β1, IL-1α and TLR4 expression compared to HCC group. These results were significant with taxifolin/alogliptin combination when compared to the use of each of these agents alone. In conclusion, taxifolin/alogliptin combination might be used as adjuvant therapy for attenuation of HCC.

Immune Interaction Map of Human SARS-CoV-2 Target Genes: Implications for Therapeutic Avenues

There exists increasing evidence that people with preceding medical conditions, such as diabetes and cancer, have a higher risk of infection with SARS-CoV-2 and are more vulnerable to severe disease. To get insights into the possible role of the immune system upon COVID-19 infection, 2811 genes of the gene ontology term “immune system process GO: 0002376” were selected for coexpression analysis of the human targets of SARS-CoV-2 (HT-SARS-CoV-2) ACE2, TMPRSS2, and FURIN in tissue samples from patients with cancer and diabetes mellitus. The network between HT-SARS-CoV-2 and immune system process genes was analyzed based on functional protein associations using STRING. In addition, STITCH was employed to determine druggable targets. DPP4 was the only immune system process gene, which was coexpressed with the three HT-SARS-CoV-2 genes, while eight other immune genes were at least coexpressed with two HT-SARS-CoV-2 genes. STRING analysis between immune and HT-SARS-CoV-2 genes plotted 19 associations of which there were eight common networking genes in mixed healthy (323) and pan-cancer (11003) tissues in addition to normal (87), cancer (90), and diabetic (128) pancreatic tissues. Using this approach, three commonly applicable druggable connections between HT-SARS-CoV-2 and immune system process genes were identified. These include positive associations of ACE2—DPP4 and TMPRSS2—SRC as well as a negative association of FURIN with ADAM17. Furthermore, 16 drugs were extracted from STITCH (score <0.8) with 32 target genes. Thus, an immunological network associated with HT-SARS-CoV-2 using bioinformatics tools was identified leading to novel therapeutic opportunities for COVID-19.

CD26/Dipeptidyl Peptidase IV and Its Multiple Biological Functions

CD26/Dipeptidyl peptidase IV (DPPIV) is a cell surface glycoprotein with numerous roles including glucose metabolism, immunomodulation, and tumorigenesis. CD26/DPPIV is well recognized in diabetes, with DPPIV inhibitors being a class of oral hypoglycemic drugs called gliptins that are commonly used to treat type two diabetes mellitus. Recent work also indicated a potential role for CD26 in infectious diseases, including COVID-19, and immune-mediated disorders such as rheumatoid arthritis, inflammatory bowel disease, and graft-versus-host disease.

In cancer, CD26/DPPIV expression has been characterized in numerous tumors such as hematologic malignancies, malignant pleural mesothelioma (MPM), renal cell carcinoma (RCC), hepatocellular carcinoma (HCC), gastrointestinal stromal tumor (GIST), and prostate, lung, colorectal, and ovarian (PLCO) cancer. Hence, CD26 has been frequently studied as a tumor biomarker and therapeutic target. CD26/DPPIV-targeted therapies have been evaluated in various cancers, including the use of anti-CD26 monoclonal antibodies as anticancer treatment in selected neoplasms.

This review highlights our current understanding of the role of CD26 in cancer, diabetes, immune-mediated diseases, and infectious diseases. Enhanced understanding of CD26 biology and function may lead to novel therapeutic approaches in multiple human diseases.

A Novel Purification Procedure for Active Recombinant Human DPP4 and the Inability of DPP4 to Bind SARS-CoV-2

Proteases catalyse irreversible posttranslational modifications that often alter a biological function of the substrate. The protease dipeptidyl peptidase 4 (DPP4) is a pharmacological target in type 2 diabetes therapy primarily because it inactivates glucagon-like protein-1. DPP4 also has roles in steatosis, insulin resistance, cancers and inflammatory and fibrotic diseases. In addition, DPP4 binds to the spike protein of the MERS virus, causing it to be the human cell surface receptor for that virus. DPP4 has been identified as a potential binding target of SARS-CoV-2 spike protein, so this question requires experimental investigation. Understanding protein structure and function requires reliable protocols for production and purification. We developed such strategies for baculovirus generated soluble recombinant human DPP4 (residues 29–766) produced in insect cells. Purification used differential ammonium sulphate precipitation, hydrophobic interaction chromatography, dye affinity chromatography in series with immobilised metal affinity chromatography, and ion-exchange chromatography. The binding affinities of DPP4 to the SARS-CoV-2 full-length spike protein and its receptor-binding domain (RBD) were measured using surface plasmon resonance and ELISA. This optimised DPP4 purification procedure yielded 1 to 1.8 mg of pure fully active soluble DPP4 protein per litre of insect cell culture with specific activity >30 U/mg, indicative of high purity. No specific binding between DPP4 and CoV-2 spike protein was detected by surface plasmon resonance or ELISA. In summary, a procedure for high purity high yield soluble human DPP4 was achieved and used to show that, unlike MERS, SARS-CoV-2 does not bind human DPP4.

Type 2 diabetes and cancer: problems and suggestions for best patient management

Diabetes and cancer are widespread worldwide and the number of subjects presenting both diseases increased over the years. The management of cancer patients having diabetes represents a challenge not only because of the complexity and heterogeneity of these pathologies but also for the lack of standardised clinical guidelines. The diagnosis of cancer is traumatizing and monopolizes the attention of both patients and caregivers. Thus, pre-existent or new-onset diabetes can be overshadowed thus increasing the risk for short- and long-term adverse events. Moreover, drugs used for each disease can interfere with the clinical course of the concomitant disease, making challenging the management of these patients. Over the years, this issue has become more relevant because of the increased patients’ life expectancy due to the improved efficacy of diabetes and cancer therapies. The purpose of this review is to highlight what is known and what should be taken into consideration to optimise the clinical management of patients with diabetes and cancer. Due to the complexity of these diseases, a multidisciplinary, shared approach, including all the protagonists involved, is necessary to improve patients’ quality of life and lifespan.

Vildagliptin, a CD26/DPP4 inhibitor, ameliorates bleomycin-induced pulmonary fibrosis via regulating the extracellular matrix

BACKGROUND

Idiopathic pulmonary fibrosis is a debilitating lung disease. CD26/DPP4 plays promotive roles in pulmonary damage and fibrosis. This study aimed to explore the roles of vildagliptin in bleomycin-induced pulmonary fibrosis, and to address its ameliorative effect on the extracellular matrix (ECM).

METHODS

Idiopathic pulmonary fibrosis mice models were induced by intratracheal injection of bleomycin. DPP4 activity was evaluated, and the fibrosis was investigated by Hematoxylin-eosin, Masson's trichrome staining and hydroxyproline assay. Expression of extracellular matrix proteins including α-SMA, collagen IV, collagen I, FN and TGF-β were analyzed by immunochemistry and western blot. Percentages of the numbers of monocytes, leukocytes, basophils and lymphocytes were classified, and inflammatory factors in plasma as well as lung tissues were examined by enzyme-linked immunosorbent assay and western blot. The influences of vildagliptin on TGF-β1-induced cell proliferation, differentiation and inflammatory factors in MRC-5 cells were detected.

RESULTS

Vildagliptin effectively attenuated inflammation and fibrosis in bleomycin-induced pulmonary tissue via inhibiting the activity of CD26/DPP4. extracellular matrix proteins were suppressed by vildagliptin. Thus, lung tissue fibrosis was efficiently alleviated by vildagliptin.

CONCLUSION

As an inhibitor of CD26/DPP4, Vildagliptin could be a promising therapeutic candidate for idiopathic pulmonary fibrosis.

Pleiotropic effects of anti-diabetic drugs: A comprehensive review

Diabetes mellitus characterized by hyperglycaemia presents an array of comorbidities such as cardiovascular and renal failure, dyslipidemia, and cognitive impairments. Populations above the age of 60 are in an urgent need of effective therapies to deal with the complications associated with diabetes mellitus. Widely used anti-diabetic drugs have good safety profiles and multiple reports indicate their pleiotropic effects in diabetic patients or models. This review has been written with the objective of identifying the widely-marketed anti-diabetic drugs which can be efficiently repurposed for the treatment of other diseases or disorders. It is an updated, comprehensive review, describing the protective role of various classes of anti-diabetic drugs in mitigating the macro and micro vascular complications of diabetes mellitus, and differentiating these drugs on the basis of their mode of action. Notably, metformin, the anti-diabetic drug most commonly explored for cancer therapy, has also exhibited some antimicrobial effects. Unlike class specific effects, few instances of drug specific effects in managing cardiovascular complications have also been reported. A major drawback is that the pleiotropic effects of anti-diabetic drugs have been mostly investigated only in diabetic patients. Thus, for effective repurposing, more clinical trials devoted to analyse the effects of anti-diabetic drugs in patients irrespective of their diabetic condition, are required.

Impact of DPP4 Inhibitors in Survival of Patients With Prostate, Pancreas, and Breast Cancer

Background: Dipeptidyl peptidase-4 (DPP4), a cell surface protein, exhibits a crucial role in tumor biology and regulation of the immune system. We aim to study the impact of DPP4 inhibitors (DPP4i) in patients with prostate cancer (PRC), pancreatic cancer (PC) and breast cancer (BC).

Methods: Using the SEER and Medicare linked database, we identified patients with PRC or PC or BC with coexisting type II diabetes mellitus between 2007 and 2015. Patients were classified into four groups: (1) not on either DPP4i or metformin (reference group), this group included patient that were on anti-diabetic agents other than metformin or DPP4i (2) metformin only, (3) DPP4i only, and (4) DPP4i along with metformin (combination group). Overall survival (OS) analyses were performed using SAS®, version 9.4.

Results: We identified 15,330 patients with PRC, 5,359 patients with PC and 16,085 patients with BC. In PRC cohort, patients on DPP4i had significant survival advantage with HR 0.77 (95% CI: 0.64–0.93), P = 0.005 when compared to the reference group. Patients taking metformin also had significant OS benefit with HR 0.87 (95% CI: 0.81–0.93), P < 0.0001 when compared to the reference group. However, in BC cohort, OS did not favor the patients taking DPP4i with HR 1.07 (95% CI: 0.93–1.25, P = 0.33). Similarly, in PC cohort, OS was indifferent for the patients on DPP4i with HR 1.07 (95% CI: 0.93–1.24, P = 0.68). Upon subgroup analyses of PRC patients, the survival favored the group taking DPP4i, irrespective of stage, use of chemotherapy, androgen-deprivation therapy, and prostatectomy or radiation therapy.

Conclusions: DPP4i seems to improve survival in PRC patients; however, not in PC or BC patients. While the exact mechanism involved remains to be elucidated, a prospective clinical trial would help to confirm these findings.

The emerging role of dipeptidyl-peptidase-4 as a therapeutic target in lung disease

Introduction: Dipeptidyl-peptidase-4 (DPP-4) is a surface bound ectopeptidase that is commonly known as CD26 or adenosine deaminase binding protein. DPP-4 is membrane anchored but it can be cleaved by numerous proteases including matrix-metalloproteinases (MMPs). DPP-4 is expressed by endothelial and epithelial cells, the kidney, intestine and cells of the immune system; it has a broad spectrum of biological functions in immune regulation, cancer biology and glucose metabolism.Areas covered: This article sheds light on the functions of DPP-4, the molecular mechanisms that govern its expression, it's role in the pathogenesis of common respiratory illnesses and potential as a therapeutic target.Expert opinion: DPP-4 has a deleterious role in respiratory disease. Its biological functions, key molecular pathways, interactions and associations are slowly being elucidated. Progressing our knowledge of the role of this multi-faceted molecule may yield vital and novel therapies for respiratory diseases such as lung cancer, asthma, and chronic obstructive pulmonary disease (COPD).

Design, synthesis, molecular simulation, and biological activities of novel quinazolinone-pyrimidine hybrid derivatives as dipeptidyl peptidase-4 inhibitors and anticancer agents

Twelve novel quinazolinone–pyrimidine hybrids were synthesized, of which some of them showed dual functions as DPP-4 inhibitors and anti-cancer agents.

Metformin in colorectal cancer: molecular mechanism, preclinical and clinical aspects

Growing evidence showed the increased prevalence of cancer incidents, particularly colorectal cancer, among type 2 diabetic mellitus patients. Antidiabetic medications such as, insulin, sulfonylureas, dipeptyl peptidase (DPP) 4 inhibitors and glucose-dependent insulinotropic peptide (GLP-1) analogues increased the additional risk of different cancers to diabetic patients. Conversely, metformin has drawn attention among physicians and researchers since its use as antidiabetic drug exhibited beneficial effect in the prevention and treatment of cancer in diabetic patients as well as an independent anticancer drug. This review aims to provide the comprehensive information on the use of metformin at preclinical and clinical stages among colorectal cancer patients. We highlight the efficacy of metformin as an anti-proliferative, chemopreventive, apoptosis inducing agent, adjuvant, and radio-chemosensitizer in various colorectal cancer models. This multifarious effects of metformin is largely attributed to its capability in modulating upstream and downstream molecular targets involved in apoptosis, autophagy, cell cycle, oxidative stress, inflammation, metabolic homeostasis, and epigenetic regulation. Moreover, the review highlights metformin intake and colorectal cancer risk based on different clinical and epidemiologic results from different gender and specific population background among diabetic and non-diabetic patients. The improved understanding of metformin as a potential chemotherapeutic drug or as neo-adjuvant will provide better information for it to be used globally as an affordable, well-tolerated, and effective anticancer agent for colorectal cancer.

The perceptions of natural compounds against dipeptidyl peptidase 4 in diabetes: from in silico to in vivo

Dipeptidyl peptidase IV (DPP-4), an incretin glucagon-like peptide-1 (GLP-1) degrading enzyme, contains two forms and it can exert various physiological functions particular in controlling blood glucose through the action of GLP-1. In diabetic use, the DPP-4 inhibitor can block the DDP-4 to attenuate GLP-1 degradation and prolong GLP-1 its action and sensitize insulin activity for the purpose of lowering blood glucose. Nonetheless the adverse effects of DPP-4 inhibitors severely hinder their clinical applications, and notably there is a clinical demand for novel DPP-4 inhibitors from various sources including chemical synthesis, herbs, and plants with fewer side effects. In this review, we highlight various strategies, namely computational biology (in silico), in vitro enzymatic and cell assays, and in vivo animal tests, for seeking natural DPP-4 inhibitors from botanic sources including herbs and plants. The pros and cons of all approaches for new inhibitor candidates or hits will be under discussion.

Dipeptidyl peptidase 4 inhibitors as novel agents in improving survival in diabetic patients with colorectal cancer and lung cancer: A Surveillance Epidemiology and Endpoint Research Medicare study

Background

Dipeptidyl peptidase 4 (DPP4) is a cell surface protein that can act as a tumor suppressor or activator, depending upon the level of expression and interaction with the microenvironment and chemokines. DPP4 inhibitors are used to treat diabetes.

Methods

We conducted this Surveillance Epidemiology and Endpoint Research‐Medicare database study to evaluate the role of DPP4 inhibitors on the overall survival (OS) of diabetic patients diagnosed with colorectal (CRC) and lung cancers.

Results

Diabetic patients with CRC or lung cancer who were treated with DPP4 inhibitors exhibited a statistically significant survival advantage (hazard ratio [HR] of 0.89; CI: 0.82‐0.97, P = 0.007) that remained significant after controlling for all other confounders. When DPP4 inhibitors were used in combination of metformin which is known to suppress cancer, the survival advantage was even more pronounced (HR of 0.83; CI: 0.77‐0.90, P < 0.0001). Data were then analyzed separately for two cancer types. In the CRC‐only cohort, the use of DPP4 inhibitors alone had a positive trend but did not meet statistically significant threshold (HR of 0.87; CI: 0.75‐1.00, P = 0.055), while the combined use of DPP4 inhibitors and metformin was associated with statistically significant survival advantage (HR of 0.77; CI: 0.67‐0.89, P = 0.003). Similarly, for the lung cancer cohort, use of DPP4 alone was not found to be statistically significant (HR of 0.93; CI: 0.83‐1.03, P = 0.153), whereas lung cancer patients treated with the combination of DPP4 inhibitors and metformin showed statistically significant survival advantage (HR of 0.88; CI: 0.80‐0.97, P = 0.010).

Conclusions

DPP4 inhibition in CRC and lung cancer is associated with improved OS, which possibly may be due to the effect of DPP4 inhibition on immunoregulation of cancer.