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

Incretin-Based Therapies and Cancer: What's New?

Growing interest in incretin-based therapies for diabetes mellitus has led to an increased evaluation of their potential effects on cancer development. This review aims to synthesize recent evidence regarding the relationship between incretin-based therapies and cancer risk. We conducted a comprehensive literature review focusing on studies investigating dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists, and dual GLP-1/glucose-dependent insulinotropic polypeptide (GIP) receptor agonists in relation to various malignancies. Current findings suggest that while these therapies demonstrate potential benefits, including weight reduction and metabolic regulation, concerns remain regarding their long-term safety profile. Notably, some studies indicate an increased risk of thyroid and pancreatic cancers, while others report protective effects against prostate, colorectal, and breast cancers. Given the complexity of their effects, further long-term studies and post-marketing surveillance are warranted. This review highlights the need for careful clinical assessment when prescribing incretin-based therapies to patients who may be at increased risk of cancer.

Epithelium-derived exosomal dipeptidyl peptidase-4 involved in arecoline-induced oral submucous fibrosis

INTRODUCTION

Dipeptidyl peptidase-4 is known to be involved in the progression of several fibrogenic diseases, but its association with oral submucous fibrosis remains unclear. This study aims to ascertain whether dipeptidyl peptidase-4 plays a role in the pathogenesis of arecoline-induced oral submucous fibrosis.

METHODS

We assessed the expression of dipeptidyl peptidase-4 in arecoline-treated epithelial cells and the exosomes derived from cells. We cocultured the fibroblast and exosomes derived from epithelium cells and assessed fibrogenic activity by measuring collagen secretion, α-SMA expression, and gel contraction capability. An animal study was conducted to confirm the fibrogenic activity of exosomes derived from arecoline-treated epithelial cells. Additionally, we employed a dipeptidyl peptidase-4 inhibitor to assess its efficacy in mitigating fibrogenesis.

RESULTS

Following arecoline treatment, an increase dipeptidyl peptidase-4 expression was observed in exosomes from the treated epithelium cells. When these exosomes cocultured with fibroblast, fibrogenic gene α-SMA was upregulated, increased collagen secretion, and enhanced gel contraction capability. In a mouse model, the administration of arecoline-treated epithelium-derived exosomes induced oral submucous fibrosis phenotype, characterized by a reduction in incisal distance and epithelial atrophy.

CONCLUSIONS

These findings offer valuable insights into clinical strategies for combating oral fibrotic disease and contribute to the foundation of future research in this field.

Association of serum and salivary dipeptidyl peptidase-4 (DPP-4) with oral cancerous and precancerous lesions; an observational diagnostic accuracy study

BACKGROUND

Enhancing the prognosis and treatment outcomes of oral cancer relies heavily on its early detection. This study aims to establish a connection between serum and salivary dipeptidyl peptidase-4 (DPP-4) levels and oral squamous cell carcinoma (OSCC), comparing them with oral potentially malignant lesions (OPMLs) and control subjects and validating salivary DPP-4 as a diagnostic marker for the early detection of oral cancer.

METHODOLOGY

Forty-five systemically healthy individuals were categorized into three groups: Group I consisted of 15 patients diagnosed with OSCC, Group II comprised 15 patients with OPMLs (including leukoplakia and oral lichen planus), and Group III included 15 participants without any oral mucosal lesions. Serum and whole unstimulated salivary samples were collected from all participants to assess DPP-4 levels using an enzyme-linked immunosorbent assay (ELISA) kit. Receiver operating characteristic (ROC) analysis was conducted to determine the area under the curve (AUC), sensitivity, specificity, and diagnostic accuracy of DPP-4.

RESULTS

Both serum and salivary DPP-4 levels were highest in the healthy group, followed by OPMLs, and lowest in the OSCC group, with statistically significant differences observed. ROC analysis demonstrated excellent diagnostic accuracy of salivary DPP-4 in distinguishing OSCC from healthy individuals, OPMLs from healthy individuals, and OSCC from OPMLs, with accuracies of 100%, 100%, and 96.67%, respectively. Salivary DPP-4 levels also exhibited a statistically significant correlation with OSCC grades.

CONCLUSIONS

DPP-4 appears to play a protective, anti-oncogenic role in maintaining oral tissue health. The remarkable diagnostic accuracy of both serum and salivary DPP-4 in discriminating between OSCC, OPMLs, and healthy controls suggests its potential utility as a well-established marker for early oral cancer diagnosis. Salivary DPP-4, being non-invasive, could serve as a convenient chair-side diagnostic tool for the early detection of OSCC.

CLINICAL TRIAL REGISTRATION

The study was retrospectively registered on clinicaltrial.gov with NCT06087042, date of registration (first posted date): 17/10/2023.

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'.

Comprehensive safety profile of dipeptidyl peptidase-4 inhibitors: a post-marketing study based on FAERS database using signal detection algorithms

BACKGROUND

Dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors) have acquired a foothold in managing type 2 diabetes mellitus, but few concerns have arisen regarding their overall safety profile. The aim of this study is to assess the potential risk of DPP-4 inhibitors by analyzing data from the FDA Adverse Event Reporting System (FAERS) database.

RESEARCH DESIGN AND METHODS

This is a retrospective study which explored the FAERS database till March 2023 for the collection of safety reports. The disproportionality analysis was performed using signal detection algorithms (SDAs) incorporating frequentist-based data mining approach such as relative reporting ratio (RRR), reporting odds ratio (ROR) and proportional reporting ratio (PRR) with 95% confidence interval (CI).

RESULTS

A total of 14,573 adverse event reports were reported in the FAERS public dashboard associated with all the included DPP-4 inhibitors. The computed PRR, ROR, and RRR indicated positive signals for DPP-4 inhibitors with cardiac failure, pancreatitis, pemphigoid, hypoglycemia, acute kidney injury and lactic acidosis. Saxagliptin showed a higher signal score for cardiac failure, while sitagliptin was more associated with pancreatitis. Moreover, alogliptin exhibited an elevated signal score associated with pancreatic carcinoma.

CONCLUSION

Several significant disproportionality signals were observed with DPP-4 inhibitors. However, clinicians have to consider the comorbidities and concomitant drugs while prescribing these drugs.

Metformin may improve the outcome of patients with colorectal cancer and type 2 diabetes mellitus partly through effects on neutrophil extracellular traps

BACKGROUND

Although metformin reduces the risk of cancer-related mortality in patents with type 2 diabetes, the mechanism of its anti-cancer effects has not been fully understood.

METHOD

Impact of metformin on survival was examined in patients who underwent curative colectomy for colorectal cancer (CRC). The effects of metformin in neutrophil extracellular traps (NETs) were examined with in-vitro experiments and multiplex immunohistochemistry of surgically resected CRC specimens.

RESULTS

Prior intake of metformin prolonged relapse-free (P = 0.036) and overall survival (P = 0.041) in 289 patients with T2DM to the comparable levels to those of 1576 non-diabetic patients. Metformin reduced the production of NETs stimulated with lipopolysaccharide or HT-29 colon cancer cells to 60% of control. Neutrophils markedly suppressed the chemotactic migration of activated T cells in an NET-dependent manner, which was reversed by metformin treatment up to approximately half of the migration without neutrophils. Immunohistochemical analysis revealed a significant association between metformin intake and a reduction in the numbers of tumor-associated neutrophils (TANs) and NETs. Simultaneously, metformin intake was found to increase the presence of CD3(+) and CD8(+) tumor-infiltrating T cells (TILs), particularly at the tumor-invasion front, especially in areas with fewer TANs and NETs.

CONCLUSION

Metformin suppresses the diabetes-associated enhancement of NET formation, which can augment the infiltration of TILs in CRC tissues. The anti-tumor effect of metformin in patients with T2DM may be, at least partly, attributable to the inhibition of NETs.

Inhibition of Dipeptidyl Peptidase-4 Activates Autophagy to Promote Survival of Breast Cancer Cells via the mTOR/HIF-1α Pathway

Autophagy plays a complex role in breast cancer cell survival, metastasis, and chemotherapeutic resistance. Dipeptidyl peptidase (DPP)-4, a therapeutic target for type 2 diabetes mellitus, is also involved in autophagic flux. The potential influence of DPP-4 suppression on cancer biology remains unknown. Here, we report that DPP-4 deficiency promotes breast cancer cell survival via the induction of autophagy by the C-X-C motif chemokine 12 (CXCL12)/C-X-C receptor 4 (CXCR4)/mammalian target of rapamycin (mTOR)/hypoxia inducible factor (HIF)-1α axis. DPP-4 knockdown and DPP-4 inhibitor KR62436 (KR) treatment both increased the levels of LC3II and HIF-1α in cultured human breast and mouse mammary cancer cells. The KR-induced autophagic phenotype in cancer cells was inhibited by treatment with the CXCR4 inhibitor AMD3100 and rapamycin. HIF-1α knockdown also suppressed breast cancer autophagy induced by KR. The autophagy inhibitor 3-methyladenine significantly blocked the KR-mediated suppression of cleaved caspase-3 levels and apoptosis in breast cancer cell lines. Finally, we found that the metformin-induced apoptosis of DPP-4-deficient 4T1 mammary cancer cells was associated with the suppression of autophagy. Our findings identify a novel role for DPP-4 inhibition in the promotion of breast cancer survival by inducing CXCL12/CXCR4/mTOR/HIF-1α axis-dependent autophagy. Metformin is a potential drug that counteracts the breast cancer cell survival system.