Safety and antitumor activity of metformin plus lanreotide in patients with advanced gastro-intestinal or lung neuroendocrine tumors: the phase Ib trial MetNET2

In retrospective studies, metformin use has been associated with better clinical outcomes in diabetic patients with advanced, well-differentiated neuroendocrine tumors (WDNETs). However, prospective evidence of metformin safety and activity is lacking. Here, we conducted the first-in-human phase Ib MetNET2 trial to investigate the safety and antitumor activity of metformin in combination with the somatostatin analog lanreotide autogel (ATG) in both diabetic and non-diabetic patients with advanced WDNETs of the gastrointestinal (GI) or thoracic tract. Enrolled patients received lanreotide ATG 120 mg plus oral metformin, up to a maximum dosage of 2550 mg/day. We enrolled 20 patients, of whom 18 (90%) and 2 (10%) had WDNETs of the GI and thoracic tract, respectively. Fourteen patients (70%) were non-diabetic. With a 5% incidence of SAEs, the study met its primary objective of demonstrating treatment safety. With a median follow-up of 39 months (95% CI 28-NE), median PFS was 24 months (95% CI 16-NE), with 12-month and 24-month PFS probability of 75% (95% CI 58-97) and 49% (95% CI 31-77), respectively. We found no statistically significant PFS differences between diabetic and non-diabetic patients. Among exploratory analyses, the presence of tumor genomic alterations in DNA damage pathways was associated with trend towards worse PFS, whereas a precocious reduction of HOMA-IR index and plasma cholesterol concentration showed a trend towards an association with better PFS. In conclusion, metformin plus lanreotide ATG is a safe and well tolerated combination treatment that is associated with promising antitumor activity in both non-diabetic and diabetic patients with WDNETs, and that warrants further investigation in larger clinical trials.

Metformin: A Potential Treatment for Acne, Hidradenitis Suppurativa and Rosacea

Metformin is a widely used drug for treatment of diabetes mellitus, due to its safety and efficacy. In addition to its role as an antidiabetic drug, numerous beneficial effects of metformin have enabled its use in various diseases. Considering the anti-androgenic, anti-angiogenic, anti-fibrotic and antioxidant properties of metformin, it may have the potential to improve chronic inflammatory skin diseases. However, further evidence is needed to confirm the efficacy of metformin in dermatological conditions, This review focuses on exploring the therapeutic targets of metformin in acne vulgaris, hidradenitis suppurativa and rosacea, by studying their pathogeneses.

Evaluating the protective effect of metformin against diclofenac-induced oxidative stress and hepatic damage: In vitro and in vivo studies

Diclofenac (DIC) is one of the most commonly prescribed non-steroidal anti-inflammatory drugs and has been shown to cause oxidative stress and liver injury. The current study investigated protective effects of metformin against DIC-induced hepatic toxicity in both in vitro and in vivo models. For the in vitro study, HepG2 cells were exposed to DIC in the presence or absence of metformin. The effect of metformin on cell viability was evaluated by MTT assay. Oxidative stress parameters (malondialdehyde (MDA), total thiol molecules (TTM), and total antioxidant capacity (TAC)) were assessed. For the in vivo study, thirty-six male Wistar rats were randomly divided into 6 groups. These groups were normal saline, metformin (200 mg/kg), DIC (50 mg/kg/day), DIC + metformin (50, 100, and 200 mg/kg/day). Histopathological studies and serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), albumin, direct and total bilirubin were measured. Also, oxidative stress parameters were assessed in liver tissue. Furthermore, expression of glutathione peroxidase (GPX)-1, -3, and -4, catalase (CAT), superoxide dismutase (SOD)-1, and -3 was examined using the real-time PCR method in hepatic tissue. In the in vitro study, metformin significantly prevented DIC-induced loss in cell viability in HepG2 cells. Metformin markedly reduced DIC-induced elevation of MDA levels and increased the TAC and TTM levels. In the in vivo study, metformin significantly prevented DIC-induced changes in hematological and histological markers. Administration of metformin significantly improved oxidative stress parameters in liver tissue. In addition, metformin increased the expression of antioxidant enzymes. Our results suggest that metformin exerts a significant protective effect against DIC-induced hepatic toxicity.

Insulin feedback is a targetable resistance mechanism of PI3K inhibition in glioblastoma

BACKGROUND

Insulin feedback is a critical mechanism responsible for the poor clinical efficacy of phosphatidylinositol 3-kinase (PI3K) inhibition in cancer, and hyperglycemia is an independent factor associated with poor prognosis in glioblastoma (GBM). We investigated combination anti-hyperglycemic therapy in a mouse model of GBM and evaluated the association of glycemic control in clinical trial data from patients with GBM.

METHODS

The effect of the anti-hyperglycemic regimens, metformin and the ketogenic diet, was evaluated in combination with PI3K inhibition in patient-derived GBM cells and in an orthotopic GBM mouse model. Insulin feedback and the immune microenvironment were retrospectively evaluated in blood and tumor tissue from a Phase 2 clinical trial of buparlisib in patients with recurrent GBM.

RESULTS

We found that PI3K inhibition induces hyperglycemia and hyperinsulinemia in mice and that combining metformin with PI3K inhibition improves the treatment efficacy in an orthotopic GBM xenograft model. Through examination of clinical trial data, we found that hyperglycemia was an independent factor associated with poor progression-free survival in patients with GBM. We also found that PI3K inhibition increased insulin receptor activation and T-cell and microglia abundance in tumor tissue from these patients.

CONCLUSION

Reducing insulin feedback improves the efficacy of PI3K inhibition in GBM in mice, and hyperglycemia worsens progression-free survival in patients with GBM treated with PI3K inhibition. These findings indicate that hyperglycemia is a critical resistance mechanism associated with PI3K inhibition in GBM and that anti-hyperglycemic therapy may enhance PI3K inhibitor efficacy in GBM patients.

Metformin Inefficiency to Lower Lipids in Vitamin B12 Deficient HepG2 Cells Is Alleviated via Adiponectin-AMPK Axis

Background: Prolonged metformin treatment decreases vitamin B12 (B12) levels, whereas low B12 is associated with dyslipidaemia. Some studies have reported that metformin has no effect on intrahepatic triglyceride (TG) levels. Although AMP-activated protein kinase (AMPK) activation via adiponectin lowers hepatic TG content, its role in B12 deficiency and metformin has not been explored. We investigated whether low B12 impairs the beneficial effect of metformin on hepatic lipid metabolism via the AMPK-adiponectin axis. Methods: HepG2 was cultured using custom-made B12-deficient Eagle's Minimal Essential Medium (EMEM) in different B12-medium concentrations, followed by a 24-h metformin/adiponectin treatment. Gene and protein expressions and total intracellular TG were measured, and radiochemical analysis of TG synthesis and seahorse mitochondria stress assay were undertaken. Results: With low B12, total intracellular TG and synthesized radiolabelled TG were increased. Regulators of lipogenesis, cholesterol and genes regulating fatty acids (FAs; TG; and cholesterol biosynthesis were increased. FA oxidation (FAO) and mitochondrial function were decreased, with decreased pAMPKα and pACC levels. Following metformin treatment in hepatocytes with low B12, the gene and protein expression of the above targets were not alleviated. However, in the presence of adiponectin, intrahepatic lipid levels with low B12 decreased via upregulated pAMPKα and pACC levels. Again, combined adiponectin and metformin treatment ameliorated the low B12 effect and resulted in increased pAMPKα and pACC, with a subsequent reduction in lipogenesis, increased FAO and mitochondrion function. Conclusions: Adiponectin co-administration with metformin induced a higher intrahepatic lipid-lowering effect. Overall, we emphasize the potential therapeutic implications for hepatic AMPK activation via adiponectin for a clinical condition associated with B12 deficiency and metformin treatment.

Metformin Hydrochloride Loaded Mucoadhesive Microspheres and Nanoparticles for Anti-Hyperglycemic and Anticancer Effects Using Factorial Experimental Design

Background

Metformin hydrochloride (HCl) microspheres and nanoparticles were formulated to enhance bioavailability and minimize side effects through sustained action and optimized drug-release characteristics. Initially, the same formulation design with different ratios of metformin HCl and Eudragit RSPO was used to formulate four batches of microspheres and nanoparticles using solvent evaporation and nanoprecipitation methods, respectively.

Methods

The produced formulations were evaluated based on particle size and shape (particle size distribution (PSD), scanning electron microscope (SEM)), incompatibility (differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR)), drug release pattern, permeation behavior, in vivo hypoglycemic effects, and in vitro anticancer potential.

Results

Compatibility studies concluded that there was minimal interaction between metformin HCl and the polymer, whereas SEM images revealed smoother, more spherical nanoparticles than microspheres. Drug release from the formulations was primarily controlled by the non-Fickian diffusion process, except for A1 and A4 by Fickian, and B3 by Super case II. Korsmeyer-Peppas was the best-fit model for the maximum formulations. The best formulations of microspheres and nanoparticles, based on greater drug release, drug entrapment, and compatibility characteristics, were attributed to the study of drug permeation by non-everted intestinal sacs, in vivo anti-hyperglycemic activity, and in vitro anticancer activity.

Conclusion

This study suggests that the proposed metformin HCl formulation can dramatically reduce hyperglycemic conditions and may also have anticancer potential.

Drug Repositioning of Metformin Encapsulated in PLGA Combined with Photothermal Therapy Ameliorates Rheumatoid Arthritis

Purpose

Rheumatoid arthritis (RA) is a highly prevalent form of autoimmune disease that affects nearly 1% of the global population by causing severe cartilage damage and inflammation. Despite its prevalence, previous efforts to prevent the perpetuation of RA have been hampered by therapeutics' cytotoxicity and poor delivery to target cells. The present study exploited drug repositioning and nanotechnology to convert metformin, a widely used antidiabetic agent, into an anti-rheumatoid arthritis drug by designing poly(lactic-co-glycolic acid) (PLGA)-based spheres. Moreover, this study also explored the thermal responsiveness of the IL-22 receptor, a key regulator of Th-17, to incorporate photothermal therapy (PTT) into the nanodrug treatment.

Materials and Methods

PLGA nanoparticles were synthesized using the solvent evaporation method, and metformin and indocyanine green (ICG) were encapsulated in PLGA in a dropwise manner. The nanodrug's in vitro anti-inflammatory properties were examined in J744 and FLS via real-time PCR. PTT was induced by an 808 nm near-infrared (NIR) laser, and the anti-RA effects of the nanodrug with PTT were evaluated in DBA/1 collagen-induced arthritis (CIA) mice models. Further evaluation of anti-RA properties was carried out using flow cytometry, immunofluorescence analysis, and immunohistochemical analysis.

Results

The encapsulation of metformin into PLGA allowed the nanodrug to enter the target cells via macropinocytosis and clathrin-mediated endocytosis. Metformin-encapsulated PLGA (PLGA-MET) demonstrated promising anti-inflammatory effects by decreasing the expression of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), increasing the expression of anti-inflammatory cytokines (IL-10 and IL-4), and promoting the polarization of M1 to M2 macrophages in J774 cells. The treatment of the nanodrug with PTT exhibited more potent anti-inflammatory effects than free metformin or PLGA-MET in CIA mice models.

Conclusion

These results demonstrated that PLGA-encapsulated metformin treatment with PTT can effectively ameliorate inflammation in a spatiotemporal manner.

Metformin ameliorates valve interstitial cell calcification by promoting autophagic flux

Calcific aortic valve disease (CAVD) is the most common heart disease of the developed world. It has previously been established that metformin administration reduces arterial calcification via autophagy; however, whether metformin directly regulates CAVD has yet to be elucidated. In the present study we investigated whether metformin alleviates valvular calcification through the autophagy-mediated recycling of Runx2. Calcification was reduced in rat valve interstitial cells (RVICs) by metformin treatment (0.5-1.5 mM) (P < 0.01), with a marked decrease in Runx2 protein expression compared to control cells (P < 0.05). Additionally, upregulated expression of Atg3 and Atg7 (key proteins required for autophagosome formation), was observed following metformin treatment (1 mM). Blocking autophagic flux using Bafilomycin-A1 revealed colocalisation of Runx2 with LC3 puncta in metformin treated RVICs (P < 0.001). Comparable Runx2 accumulation was seen in LC3 positive autolysosomes present within cells that had been treated with both metformin and hydroxychloroquine in combination (P < 0.001). Mechanistic studies employing three-way co-immunoprecipitation with Runx2, p62 and LC3 suggested that Runx2 binds to LC3-II upon metformin treatment in VICs. Together these studies suggest that the utilisation of metformin may represent a novel strategy for the treatment of CAVD.

Low glucose availability potentiates the effects of metformin on model T cell activation and exhaustion markers in vitro

Modulation of immune cell metabolism is one of promising strategies to improve cancer immunotherapies. Metformin is an anti-diabetic drug with potential anti-cancer effects, ranging from normalization of blood glucose and insulin levels, direct anti-proliferative effects on cancer cells to emerging immunomodulatory effects on anti-tumor immunity. Metformin can reduce tumor hypoxia and PD-L1 expression, as well as normalize or improve T cell function and potentiate the effect of immune checkpoint inhibitors, making it a promising adjuvant to immunotherapy of tumors with poor response such as triple negative breast cancer (TNBC). However, although the effects of metformin on cancer cells are glucose-dependent, the role of glucose in modulating its effect on T cells has not been systematically studied. We thus investigated the effect of metformin as a function of glucose level on Jurkat cell and PBMC T cell models in vitro. While low metformin concentrations had little effect on T cell function, high concentration reduced proliferation and IFN-γ secretion in both models and induced a shift in T cell populations from memory to effector subsets. The PD-1/CD69 ratio was improved by high metformin in T cells from PBMC. Low glucose and metformin synergistically reduced PD-1 and CD69 expression and IFN-γ secretion in T cells from PBMC. Low glucose level itself suppressed Jurkat cell function due to their limited metabolic plasticity, but had limited effects on T cells from PBMC apart from reduced proliferation. Conversely, high glucose did not strongly affect either T cell model. Metformin in combination with glycolysis inhibitor 2-deoxy-D-glucose (2DG) reduced PD-1 in Jurkat cells, but also strongly suppressed their function. However, low, physiologically achievable 2DG concentration itself reduced PD-1 while mostly maintaining IL-2 secretion and, interestingly, even strongly increased IFN-γ secretion regardless of glucose level. Overall, glucose metabolism can importantly influence some of the effects of metformin on T cell functionality in the tumor microenvironment. Additionally, we show that 2DG could potentially improve the anti-tumor T cell response.

Metformin-Loaded Hyaluronic Acid-Derived Carbon Dots for Targeted Therapy against Hepatocellular Carcinoma by Glutamine Metabolic Reprogramming

Metabolic reprogramming is a significant hallmark of cancer that promotes chemoresistance by allowing tumor tissues to adapt to changes in the tumor microenvironment caused by anticancer therapies. Hepatocellular carcinoma (HCC), one of the most common types of primary tumors, is associated with recurrent metabolic reprogramming that maximizes cancer cell growth and proliferation. Herein, we developed metformin (MET)-loaded hyaluronic acid (HA)-derived carbon dots (HA-CD-MET) by a simple and green method with no involvement of any additives. HA-CD-MET was utilized for specifically binding the CD44 receptor overexpressed in HCC and induced glutamine metabolic rewiring to inhibit HCC cell proliferation. Exposure to HA-CD-MET resulted in ∼6.5-fold better anticancer efficacy against CD44+ Hep3B cells in comparison to CD44-, HepG2, and noncancerous HEK293 cells at a very low dose of 80 μg/mL. Moreover, treatment of three-dimensional (3D) tumor spheroid model of HCC (Hep3B) with HA-CD-MET resulted in ∼4.9-fold reduction in tumor size. This improved anticancer efficacy of HA-CD-MET was attributed to the inhibition of glutaminase-1 (GLS-1), a mitochondrial enzyme that hydrolyzes glutamine into glutamate as confirmed from immunofluorescence and immunoblotting experiments. Furthermore, treatment with HA-CD-MET resulted in downregulation of glucose transporter-1 (GLUT-1) in Hep3B cells. Consequently, cancer cells were starved from essential nutrients, glutamine, and glucose, leading to the enhancement in intracellular ROS generation. This increase in intracellular ROS accumulation activated AMP-activated protein kinase (AMPK) and inhibited AKT phosphorylation, leading to cancer cell apoptosis. Thus, this study offers the targeting of metabolic reprogramming by HA-CD-MET that opens up a promising strategy for therapeutic intervention in hepatocarcinoma.

Protective effects of metformin on pancreatic β-cell ferroptosis in type 2 diabetes in vivo

Metformin (Met) is the recommended first-line therapeutic drug for type 2 diabetes mellitus (T2DM) and exerts protective effects on β-cell damage. Ferroptosis, a new form of cell death, is associated with pancreatic islet injury in patients with T2DM. However, the protective effects of Met treatment against β-cell damage through ferroptosis modulation remain under-reported. This study investigated the in vivo effects of Met treatment on pancreatic β-cell ferroptosis using two different diabetic mouse models, namely, low-dose streptozotocin (STZ) and high-fat diet (HFD)-induced diabetic mice and db/db mice. Met treatment significantly restored insulin release, reduced cell mortality, and decreased the overproduction of lipid-related reactive oxygen species in the islets of both STZ/HFD-induced diabetic mice and db/db mice. Administration of the Ras-selective lethal 3 injection significantly attenuated the antiferroptosis effects of Met. Mechanistically, Met treatment alleviated β-cell ferroptosis in T2DM, which was associated with the regulation of the GPX4/ACSL4 axis in the islets. In conclusion, our findings highlight the significance of ferroptosis in T2DM β-cell damage and provide novel insights into the protective effects of Met against islet β cells.

The metabolic response of human trophoblasts derived from term placentas to metformin

AIMS/HYPOTHESIS

Metformin is increasingly used therapeutically during pregnancy worldwide, particularly in the treatment of gestational diabetes, which affects a substantial proportion of pregnant women globally. However, the impact on placental metabolism remains unclear. In view of the association between metformin use in pregnancy and decreased birthweight, it is essential to understand how metformin modulates the bioenergetic and anabolic functions of the placenta.

METHODS

A cohort of 55 placentas delivered by elective Caesarean section at term was collected from consenting participants. Trophoblasts were isolated from the placental samples and treated in vitro with clinically relevant doses of metformin (0.01 mmol/l or 0.1 mmol/l) or vehicle. Respiratory function was assayed using high-resolution respirometry to measure oxygen concentration and calculated [Formula: see text]. Glycolytic rate and glycolytic stress assays were performed using Agilent Seahorse XF assays. Fatty acid uptake and oxidation measurements were conducted using radioisotope-labelled assays. Lipidomic analysis was conducted using LC-MS. Gene expression and protein analysis were performed using RT-PCR and western blotting, respectively.

RESULTS

Complex I-supported oxidative phosphorylation was lower in metformin-treated trophoblasts (0.01 mmol/l metformin, 61.7% of control, p<0.05; 0.1 mmol/l metformin, 43.1% of control, p<0.001). The proton efflux rate arising from glycolysis under physiological conditions was increased following metformin treatment, up to 23±5% above control conditions following treatment with 0.1 mmol/l metformin (p<0.01). There was a significant increase in triglyceride concentrations in trophoblasts treated with 0.1 mmol/l metformin (p<0.05), particularly those of esters of long-chain polyunsaturated fatty acids. Fatty acid oxidation was reduced by ~50% in trophoblasts treated with 0.1 mmol/l metformin compared with controls (p<0.001), with no difference in uptake between treatment groups.

CONCLUSIONS/INTERPRETATION

In primary trophoblasts derived from term placentas metformin treatment caused a reduction in oxidative phosphorylation through partial inactivation of complex I and potentially by other mechanisms. Metformin-treated trophoblasts accumulate lipids, particularly long- and very-long-chain polyunsaturated fatty acids. Our findings raise clinically important questions about the balance of risk of metformin use during pregnancy, particularly in situations where the benefits are not clear-cut and alternative therapies are available.

Regulation of Intestinal Flora and Immune Response by Cyanidin Exhibits Protective Effect against Type-2 Diabetes in Rat Model

In the current study the effects of metformin and cyanidin on the immune system and intestinal flora in rats with type-2 diabetes was investigated. The findings showed that metformin or cyanidin treatment considerably reduced the rise in body weight and glucose levels induced by type-2 diabetes. The type-2 diabetic rats' glucose tolerance was significantly increased by cyanidin administration comparable to that of metformin. Cyanidin administration resulted in a significant reduction in serum cholesterol and low-density lipoprotein (LDL) levels in rats with type-2 diabetes. Treatment with cyanidin significantly increased the ratio of high-density lipoprotein to low-density lipoprotein in type-2 diabetes rats. Cyanidin administration significantly raised the ratio of Firmicutes to Bacteroidetes in the fecal samples of type-2 diabetic rats compared to the model group. In comparison to the model group, it also significantly raised the levels of Lactobacillus intestinalis, Lactobacillus gasseri, and Lactobacillus reuteri in the type-2 diabetes rats. In type-2 diabetes rat fecal samples, the abundance of Christensenellaceae significantly increased while Enterobacteriaceae and Proteobacteria were found to decrease upon cyanidin administration. Furthermore, cyanidin administration to the rats with type-2 diabetes significantly improved the glucose homeostasis. In conclusion, the study demonstrates that cyanidin enhances glucose homeostasis in rats with type-2 diabetes, potentially through controlling intestinal flora. Thus, cyanidin may be looked into more as a possible therapeutic agent for type 2 diabetes.

Hepatic mitochondrial NAD + transporter SLC25A47 activates AMPKα mediating lipid metabolism and tumorigenesis

BACKGROUND AIMS

SLC25A47 was initially identified as a mitochondrial HCC-downregulated carrier protein, but its physiological functions and transport substrates are unknown. We aimed to investigate the physiological role of SLC25A47 in hepatic metabolism.

APPROACH RESULTS

In the treatment of hepatocytes with metformin, we found that metformin can transcriptionally activate the expression of Slc25a47 , which is required for AMP-activated protein kinase α (AMPKα) phosphorylation. Slc25a47 -deficient mice had increased hepatic lipid content, triglycerides, and cholesterol levels, and we found that Slc25a47 deficiency suppressed AMPKα phosphorylation and led to an increased accumulation of nuclear SREBPs, with elevated fatty acid and cholesterol biosynthetic activities. Conversely, when Slc25a47 was overexpressed in mouse liver, AMPKα was activated and resulted in the inhibition of lipogenesis. Moreover, using a diethylnitrosamine-induced mouse HCC model, we found that the deletion of Slc25a47 promoted HCC tumorigenesis and development through the activated mammalian target of rapamycin cascade. Employing homology modeling of SLC25A47 and virtual screening of the human metabolome database, we demonstrated that NAD + was an endogenous substrate for SLC25A47, and the activity of NAD + -dependent sirtuin 3 declined in Slc25a47 -deficient mice, followed by inactivation of AMPKα.

CONCLUSIONS

Our findings reveal that SLC25A47, a hepatocyte-specific mitochondrial NAD + transporter, is one of the pharmacological targets of metformin and regulates lipid homeostasis through AMPKα, and may serve as a potential drug target for treating NAFLD and HCC.

mTORC1 inhibition may improve T lymphocytes affected by aging

BACKGROUND

Due to the increase of the elderly's population and related social and economic problems, it is very important to provide strategies on health. In this regard, induction of T lymphocytes responses, the most important cells of the immune system, may be a good approach. Among different agents considered as antiaging factors, mTORC1 pathway inhibitors are significant. So, the purpose of this study was to evaluate the effect of two mTORC1 inhibitors, Everolimus and Metformin, on age-related features of activated T cells.

MATERIALS AND METHODS

Optimum doses of drugs was determined with evaluating the effect of treatments on IL-2 gene expression. T cells isolated from old and young mice were treated with drugs and PHA. IL-2 production was evaluated by ELISA. Also, the expression of CD28, PD-1, and KLRG-1, proliferation, and intracellular oxidative stress were assessed by flow cytometry-based assays, phenotyping, CFSE, and DCF-DA assay respectively.

RESULTS

Both drugs increased IL-2 production in the T cells of old mice. Also, using drugs especially Metformin could improve age-related phenotypical markers and increase the proliferation of T cells of old mice significantly. In addition, Metformin and Everolimus reduced intracellular oxidative stress in aged cells. However, the effect of both drugs on the T cells of young mice wasn't significant or was in opposite to the results of old mice T cells.

DISCUSSION

In line with studies noting mTOR inhibitors as antiaging drugs, Metformin and Everolimus may improve T cells affected from aging in vitro, and a decrease in intracellular oxidative stress may be one of their mechanism of function.

Transferrin functionalized poloxamer-chitosan nanoparticles of metformin: physicochemical characterization, in-vitro, and Ex-vivo studies

OBJECT

We report the preparation, characterization, and in-vitro therapeutic evaluation of Metformin-Loaded, Transferrin-Poloxamer-Functionalized Chitosan Nanoparticles (TPMC-NPs) for their repurposing in Alzheimer's disease (AD).

SIGNIFICANCE

Usefulness of this work to establish the repurposing of metformin for the treatment of AD.

METHODS

The TPMC-NPs were prepared by ionic gelation method using sodium tripolyphosphate. The modification and functionalization were confirmed by FTIR and 1H-NMR spectroscopy. The physicochemical characterization was performed using DLS, FTIR,1H-NMR, CD spectroscopy, SEM, DSC, PXRD, HR-TEM, and hot-stage microscopy.

RESULTS

The size, PDI, percent entrapment efficiency, and percent drug loading of TPMC-NPs were found to be 287.4 ± 9.5, 0.273 ± 0.067, 81.15 ± 7.17%, 11.75%±8.21%, respectively. Electron microscope analysis revealed smooth and spherical morphology. The transferrin conjugation efficiency was found to be 46% by the BCA method. CD spectroscopy confirmed no significant loss of the secondary structure of transferrin after conjugation. PXRD data indicated the amorphous nature of the TPMC-NPs. Hot-stage microscopy and DSC confirmed the thermal stability of TPMC-NPs. The in-vitro drug release showed a sustained release at pH 7.4. The DPPH assay displayed 80% antioxidant activity of TPMC-NPs in comparison with metformin and blank NPs. The in-vitro cytotoxicity assay revealed 69.60% viable SH- SY5Y cells at 100 µg/mL of TPMC NPs. The ex-vivo nasal ciliotoxicity and mucoadhesion studies showed no significant toxicity, and 98.16% adhesion, respectively. The nasal permeability study showed the release of metformin within 30 min from TPMC-NPs.

CONCLUSION

The obtained results suggested the usefulness of TPMC-NPs in the treatment of AD via the intranasal route.

Metformin HCl-loaded transethosomal gel; development, characterization, and antidiabetic potential evaluation in the diabetes-induced rat model

Herein we designed, optimized, and characterized the Metformin Hydrochloride Transethosomes (MTF-TES) and incorporate them into Chitosan gel to develop Metformin Hydrochloride loaded Transethosomal gel (MTF-TES gel) that provides a sustained release, improved transdermal flux and improved antidiabetic response of MTF. Design Expert® software (Ver. 12, Stat-Ease, USA) was applied for the statistical optimization of MTF-TES. The formulation with Mean Particle Size Distribution (MPSD) of 165.4 ± 2.3 nm, Zeta Potential (ZP) of -21.2 ± 1.9 mV, Polydispersity Index (PDI) of 0.169 ± 0.033, and MTF percent Entrapment Efficiency (%EE) of 89.76 ± 4.12 was considered to be optimized. To check the chemical incompatibility among the MTF and other formulation components, Fourier Transform Infrared (FTIR) spectroscopy was performed and demonstrated with no chemical interaction. Surface morphology, uniformity, and segregation were evaluated through Transmission Electron Microscopy (TEM). It was revealed that the nanoparticles were spherical and round in form with intact borders. The fabricated MTF-TES has shown sustained release followed by a more pronounced effect in MTF-TES gel as compared to the plain MTF solution (MTFS) at a pH of 7.4. The MTF-TES has shown enhanced permeation followed by MTF-TES gel as compared to the MTFS at a pH of 7.4. In vivo antidiabetic assay was performed and results have shown improved antidiabetic potential of the MTF-TES gel, in contrast to MTF-gel. Conclusively, MTF-TES is a promising anti-diabetic candidate for transdermal drug delivery that can provide sustained MTF release and enhanced antidiabetic effect.

Efficacy of Bee Products (Anzer Honey, Pollen and Propolis) in Detection and Healing of Damage Induced by Antidiabetic Drug Vildagliptin/Metformin Hydrochloride in Healthy Human Pancreatic Cells: Cytotoxic, Genotoxic and Biochemical Studies

BACKGROUND AND OBJECTIVE

Although drugs are powerful therapeutic agents, they have a range of side effects. These side effects are sometimes cellular and not clinically noticeable. Vildagliptin/metformin hydrochloride is one of the most widely used oral antidiabetic drugs with two active ingredients. In this study, we investigated its harmful effects on the metabolic activation system in healthy human pancreatic cells "hTERT-HPNE", and we aimed to improve these harmful effects by natural products. To benefit from the healing effect, we used the unique natural products produced by the bees of the Anzer Plateau in the Eastern Black Sea Region of Turkey.

METHODS

Cytotoxic and genotoxic effects of the drug were investigated by different tests, such as MTT, flow cytometry-apoptosis and comet assays. Anzer honey, pollen and propolis were analyzed by gas chromatography/mass spectrometry (G/C-MS). A total of 19 compounds were detected, constituting 99.9% of the samples.

RESULTS

The decrease in cell viability at all drug concentrations was statistically significant compared to the negative control (P<0.05). A statistically significant decrease was detected in the apoptosis caused by vildagliptin/metformin hydrochloride with the supplementation of Anzer honey, pollen and propolis in hTERT-HPNE cells (P<0.05).

CONCLUSION

This study can contribute to other studies testing the healing properties of natural products against the side effects of oral antidiabetics in human cells. In particular, Anzer honey, pollen and propolis can be used as additional foods to maintain cell viability and improve heal damage and can be evaluated against side effects in other drug studies.

Effects of metformin on parasitological, pathological changes in the brain and liver and immunological aspects during visceral toxocariasis in mice

There are currently insufficient anthelmintic medications available for the treatment of toxocariasis. For instance, Albendazole (ABZ) is the preferred medication, but its effectiveness against tissue-dwelling parasites is limited. In addition, Metformin (MTF) is a widely used oral antidiabetic medication that is considered to be safe for treatment. This study aimed to investigate any potential effects of MTF, alone or in combination with ABZ, on mice infections caused by Toxocara canis (T. canis). The efficacy of the treatment was assessed in the acute and chronic phases of the infection by larval recovery and histopathological, immunohistochemical, and biochemical studies. The results showed that combined therapy significantly reduced larval counts in the liver, brain, and muscles and ameliorated hepatic and brain pathology. It reduced oxidative stress and TGF-β mRNA expression and increased FGF21 levels in the liver. It decreased TNF-α levels and MMP-9 expression in the brain. In addition, it increased serum levels of IL-12 and IFN-γ and decreased serum levels of IL-4 and IL-10. In the acute and chronic phases of the infection, the combined treatment was more effective than ABZ alone. In conclusion, this study highlights the potential role of MTF as an adjuvant in the treatment of experimental T. canis infection when administered with ABZ.

Anticancer potentials of metformin loaded coconut oil nanoemulsion on MCF-7, HepG2 and HCT-116 cell lines

In order to load metformin in a nano formula and evaluate the produced nano form towards cancer cells, metformin was loaded on natural carrier coconut oil. The formed metformin-loaded coconut oil nanoemulsion was characterized by Zeta potential, particle size, drug content, drug release, and drug stability. The formed nanoemulsion was evaluated towards MCF-7, HepG2, and HCT-116 cell lines. Cell cycle analysis and apoptosis mechanism were studied. The nanoemulsion was created using deionized water, 1.5% Span 20, 1.5% Tween 80, 1.5% coconut oil, and 0.5% Metformin in an ultrasonicator to produce a homogenous solution. The anticancer activities of the metformin-loaded coconut nanoemulsion were highly improved compared to non-formulated metformin with IC50s of 8.3 ± 0.1 µg/ml, 12 ± 1.5 µg/ml, 2.685 ± 0.3 µg/ml for MCF-7, HepG2, and HCT-116 cell lines, respectively. There was a 76.5 ± 2.3 and 78.3 ± 3.2% increase in the number of apoptotic cells of MCF-7 and HepG2 cells after nanoemulsion treatment. This formula may be considered a new anticancer medication.

Enhanced fatty acid oxidation through metformin and baicalin as therapy for COVID-19 and associated inflammatory states in lung and kidney

Progressive respiratory failure is the primary cause of death in the coronavirus disease 2019 (COVID-19) pandemic. It is the final outcome of the acute respiratory distress syndrome (ARDS), characterized by an initial exacerbated inflammatory response, metabolic derangement and ultimate tissue scarring. A positive balance of cellular energy may result crucial for the recovery of clinical COVID-19. Hence, we asked if two key pathways involved in cellular energy generation, AMP-activated protein kinase (AMPK)/acetyl-CoA carboxylase (ACC) signaling and fatty acid oxidation (FAO) could be beneficial. We tested the drugs metformin (AMPK activator) and baicalin (CPT1A activator) in different experimental models mimicking COVID-19 associated inflammation in lung and kidney. We also studied two different cohorts of COVID-19 patients that had been previously treated with metformin. These drugs ameliorated lung damage in an ARDS animal model, while activation of AMPK/ACC signaling increased mitochondrial function and decreased TGF-β-induced fibrosis, apoptosis and inflammation markers in lung epithelial cells. Similar results were observed with two indole derivatives, IND6 and IND8 with AMPK activating capacity. Consistently, a reduced time of hospitalization and need of intensive care was observed in COVID-19 patients previously exposed to metformin. Baicalin also mitigated the activation of pro-inflammatory bone marrow-derived macrophages (BMDMs) and reduced kidney fibrosis in two animal models of kidney injury, another key target of COVID-19. In human epithelial lung and kidney cells, both drugs improved mitochondrial function and prevented TGF-β-induced renal epithelial cell dedifferentiation. Our results support that favoring cellular energy production through enhanced FAO may prove useful in the prevention of COVID-19-induced lung and renal damage.

Metformin restores prohormone processing enzymes and normalizes aberrations in secretion of proinsulin and insulin in palmitate-exposed human islets

AIM

To elucidate how proinsulin synthesis and insulin was affected by metformin under conditions of nutrient overstimulation.

MATERIALS AND METHODS

Isolated human pancreatic islets from seven donors were cultured at 5.5 mmol/L glucose and 0.5 mmol/L palmitate for 12, 24 or 72 h. Metformin (25 μmol/L) was introduced after initial 12 h with palmitate. Proinsulin and insulin were measured. Expression of prohormone convertase 1/3 (PC1/3) and carboxypeptidase E (CPE), was determined by western blot. Adolescents with obesity, treated with metformin and with normal glucose tolerance (n = 5), prediabetes (n = 14), or type 2 diabetes (T2DM; n = 7) were included. Fasting proinsulin, insulin, glucose, 2-h glucose and glycated haemoglobin were measured. Proinsulin/insulin ratio (PI/I) was calculated.

RESULTS

In human islets, palmitate treatment for 12 and 24 h increased proinsulin and insulin proportionally. After 72 h, proinsulin but not insulin continued to increase which was coupled with reduced expression of PC1/3 and CPE. Metformin normalized expression of PC1/3 and CPE, and proinsulin and insulin secretion. In adolescents with obesity, before treatment, fasting proinsulin and insulin concentrations were higher in subjects with T2DM than with normal glucose tolerance. PI/I was reduced after metformin treatment in subjects with T2DM as well as in subjects with prediabetes, coupled with reduced 2-h glucose and glycated haemoglobin.

CONCLUSIONS

Metformin normalized proinsulin and insulin secretion after prolonged nutrient-overstimulation, coupled with normalization of the converting enzymes, in isolated islets. In adolescents with obesity, metformin treatment was associated with improved PI/I, which was coupled with improved glycaemic control.

Targeted Inhibition of Hsp90 in Combination with Metformin Modulates Programmed Cell Death Pathways in A549 Lung Cancer Cells

The pathophysiology of lung cancer is dependent on the dysregulation in the apoptotic and autophagic pathways. The intricate link between apoptosis and autophagy through shared signaling pathways complicates our understanding of how lung cancer pathophysiology is regulated. As drug resistance is the primary reason behind treatment failure, it is crucial to understand how cancer cells may respond to different therapies and integrate crosstalk between apoptosis and autophagy in response to them, leading to cell death or survival. Thus, in this study, we have tried to evaluate the crosstalk between autophagy and apoptosis in A549 lung cancer cell line that could be modulated by employing a combination therapy of metformin (6 mM), an anti-diabetic drug, with gedunin (12 µM), an Hsp90 inhibitor, to provide insights into the development of new cancer therapeutics. Our results demonstrated that metformin and gedunin were cytotoxic to A549 lung cancer cells. Combination of metformin and gedunin generated ROS and promoted MMP loss and DNA damage. The combination further increased the expression of AMPKα1 and promoted the nuclear localization of AMPKα1/α2. The expression of Hsp90 was downregulated, further decreasing the expression of its clients, EGFR, PIK3CA, AKT1, and AKT3. Inhibition of the EGFR/PI3K/AKT pathway upregulated TP53 and inhibited autophagy. The combination was promoting nuclear localization of p53; however, some cytoplasmic signals were also detected. Further increase in the expression of caspase 9 and caspase 3 was observed. Thus, we concluded that the combination of metformin and gedunin upregulates apoptosis by inhibiting the EGFR/PI3K/AKT pathway and autophagy in A549 lung cancer cells.

Imeglimin profoundly affects the circadian clock in mouse embryonic fibroblasts

OBJECTIVE

Imeglimin is a novel antidiabetic drug structurally related to metformin. Metformin has been shown to modulate the circadian clock in rat fibroblasts. Accordingly, in the present study, we aimed to determine whether imeglimin can impact the circadian oscillator in mouse embryonic fibroblasts (MEFs).

METHODS

MEFs carrying a Bmal1-Emerald luciferase (Bmal1-ELuc) reporter were exposed to imeglimin (0.1 or 1 mM), metformin (0.1 or 1 mM), a nicotinamide phosphoribosyltransferase inhibitor FK866, and/or vehicle. Subsequently, Bmal1-ELuc expression and clock gene mRNA expression levels were measured at 10-min intervals for 55 h and 4-h intervals for 32 h, respectively.

RESULTS

Imeglimin significantly prolonged the period (from 26.3 to 30.0 h at 0.1 mM) and dose-dependently increased the amplitude (9.6-fold at 1 mM) of the Bmal1-ELuc expression rhythm; however, metformin exhibited minimal effects on these parameters. Moreover, imeglimin notably impacted the rhythmic mRNA expression of clock genes (Bmal1, Per1, and Cry1). The concurrent addition of FK866 partly inhibited the effects of imeglimin on both Bmal1-ELuc expression and clock gene mRNA expression.

CONCLUSION

Collectively, these results reveal that imeglimin profoundly affects the circadian clock in MEFs. Further studies are needed to evaluate whether imeglimin treatment could exert similar effects in vivo.

NDUFA4 promotes the progression of head and neck paraganglioma by inhibiting ferroptosis

NDUFA4 is a component of respiratory chain-oxidative phosphorylation pathway. NDUFA4 is highly expressed in tumor tissues, but little is known about the function of NDUFA4 in head and neck paraganglioma (HNPGL). We examined NDUFA4 expression in tissues from 10 HNPGL patients and 6 controls using qRT-PCR and Western blotting. NDUFA4 knockdown PGL-626 cells were established by using lentivirus infection and puromycin screening. Cell viability, ATP production, lipid reactive oxygen species, and mitochondrial membrane potential assays were performed to investigate the ferroptotic effects in NDUFA4 deficiency HNPGL cancer cells. Xenograft mouse model was created to detect the synergetic antitumor action between NDUFA4 deficiency and Metformin. NDUFA4 was upregulated in tumor tissues of HNPGL patients. NDUFA4 knockdown impaired the assembly of mitochondrial respiratory chain complexes and decreased the production of ATP and reduced cancer cell viability. Mechanistically, NDUFA4 knockdown increased cell ferroptosis, which further promoted Metformin-induced ferroptosis in PGL-626 cells. Therefore, NDUFA4 deficiency enhanced Metformin-mediated inhibition of the HNPGL progression in mice. In conclusion, NDUFA4 promotes the progression of HNPGL, and NDUFA4 knockdown enhances Metformin-mediated inhibition of the HNPGL progression in a mouse model.

Dalbergiella welwitschia (Baker) Baker f. alkaloid-rich extracts attenuate liver damage in streptozotocin-induced diabetic rats

This experiment was conducted to evaluate the Dalbergiella welwitschia alkaloid-rich extracts on liver damage in streptozotocin-induced diabetic rats. Hence, to induce diabetes, 45 mg/kg body weight of streptozotocin was intraperitoneally injected into the Wistar rats. Subsequently, 5 % (w/v) of glucose water was given to the induced animals for 24 h. Thus, the animals (48) were grouped into five groups (n = 8), containing normal control (NC), diabetic control (DC), diabetic rats placed on low (50 mg/kg body weight) and high (100 mg/kg body weight) doses of D. welwitschi alkaloid-rich leaf extracts (i.e. DWL and DWH respectively), and diabetic rats administered 200 mg/kg body weight of metformin (MET). The animals were sacrificed on the 21st day of the experiment, blood and liver were harvested, and different liver damage biomarkers were evaluated. The results obtained demonstrated that diabetic rats administered DWL, DWH and MET significantly (p < 0.05) increased hepatic AST, ALT, albumin, SOD, CAT, GSH, and GPX levels when compared to DC with no significant (p > 0.05) different when compared with NC. Also, diabetic rats administered DWL, DWH and MET revealed a significant (p < 0.05) decrease in GGT and MDA levels, as well as, fragmented DNA and protein carbonyl levels when compared to DC with no significant (p > 0.05) different when compared with NC. In addition, histological examination revealed that diabetic rats placed on DWL, DWH and MET normalized the hepatocytes. Consequently, it can be inferred that alkaloid-rich extracts from D. welwitschi leaf could be helpful in improving liver damage associated with diabetes mellitus rats.

Metformin alleviates sodium arsenite-induced hepatotoxicity and glucose intolerance in mice by suppressing oxidative stress, inflammation, and apoptosis

BACKGROUND

Epidemiological studies have shown that exposure to sodium arsenite (NaAsO2) causes diabetes and hepatotoxicity. Metformin (MET), an oral hypoglycemic agent, has long been used in diabetes therapy. In addition, MET has been shown to have hepatoprotective effects. In this study, we investigated the effects of MET on NaAsO2-induced hepatotoxicity and glucose intolerance in mice.

METHODS

Mice were divided into four groups: Groups I and II received distilled water and NaAsO2 (10 mg/kg, p.o.) for five weeks, respectively. Groups III and IV were treated with NaAsO2 (10 mg/kg, p.o.) for three weeks, followed by MET (125 and 250 mg/kg, p.o.) for the last two weeks before NaAsO2. A glucose tolerance test was performed on day 35. The serum and tissue parameters were also evaluated.

RESULTS

Histopathological examination revealed NaAsO2-induced liver and pancreatic damage. NaAsO2 caused hyperglycemia, glucose intolerance, and a significant increase in liver function enzymes. Administration of NaAsO2 significantly reduced hepatic superoxide dismutase, catalase, glutathione peroxidase, and total thiol levels and increased the content of reactive thiobarbituric acid substances. In addition, it led to an increase in liver nitric oxide levels and protein expression of tumor necrosis factor-α, nuclear factor kappa B, and cysteine-aspartic proteases-3. In contrast, treatment with MET (250 mg/kg) significantly improved NaAsO2-induced biochemical and histopathological changes.

CONCLUSION

Our findings suggest that the significant effects of MET against NaAsO2-induced hepatotoxicity and glucose intolerance may be exerted via the regulation of oxidative stress, followed by suppression of inflammation and apoptosis.

The Differential Effect of Metformin on Osteocytes, Osteoblasts, and Osteoclasts

PURPOSE OF REVIEW

Metformin is an anti-glycemic agent, which is widely prescribed to diabetes patients. Although its alleged role on bone strength has been reported for some time, this review focuses primarily on the recent mechanistical insights of metformin on osteocytes, osteoblasts, and osteoclasts.

RECENT FINDINGS

Overall, metformin contributed to steering anabolic activity in osteocytes. It caused lower expression in osteocytes of the negative regulators of bone formation sclerostin and DKK1. Likewise, the osteoclastogenesis function of osteoblasts was also skewed towards lower RANKL and higher OPG expressions. Osteoblast lineage cells generally responded to metformin by activating bone formation parameters, such as alkaline phosphatase activity, higher expression of anabolic members of the Wnt pathway, transcription factor Runx2, bone matrix protein proteins, and subsequent mineralization. Metformin affected osteoclast formation and activity in a negative way, reducing the number of multinucleated cells in association with lower expression of typical osteoclast markers and with inhibited resorption. A common denominator studied in all three cell types is its beneficial effect on activating phosphorylated AMP kinase (AMPK) which is associated with the coordination of energy metabolism. Metformin differentially affects bone cells, shifting the balance to more bone formation. Although metformin is a drug prescribed for diabetic patients, the overall bone anabolic effects on osteocytes and osteoblasts and the anti-catabolic effect on osteoclast suggest that metformin could be seen as a promising drug in the bone field.

On the wake of metformin: Do anti-diabetic SGLT2 inhibitors exert anti-aging effects?

Here we propose that SGLT2 inhibitors (SGLT2i), a class of drugs primarily used to treat type 2 diabetes, could also be repositioned as anti-aging senomorphic drugs (agents that prevent the extrinsic harmful effects of senescent cells). As observed for metformin, another anti-diabetic drug with established anti-aging potential, increasing evidence suggests that SGLT2i can modulate some relevant pathways associated with the aging process, such as free radical production, cellular energy regulation through AMP-activated protein kinase (AMPK), autophagy, and the activation of nuclear factor (NF)-kB/inflammasome. Some interesting pro-healthy effects were also observed on human microbiota. All these mechanisms converge on fueling a systemic proinflammatory condition called inflammaging, now recognized as the main risk factor for accelerated aging and increased risk of age-related disease development and progression. Inflammaging can be worsened by cellular senescence and immunosenescence, which contributes to the increased burden of senescent cells during aging, perpetuating the proinflammatory condition. Interestingly, increasing evidence suggested the direct effects of SGLT-2i against senescent cells, chronic activation of immune cells, and metabolic alterations induced by overnutrition (meta-inflammation). In this framework, we analyzed and discussed the multifaceted impact of SGLT2i, compared with metformin effects, as a potential anti-aging drug beyond diabetes management. Despite promising results in experimental studies, rigorous investigations with well-designed cellular and clinical investigations will need to validate SGLT2 inhibitors' anti-aging effects.

Metformin Improves Comorbid Depressive Symptoms in Mice with Allergic Rhinitis by Reducing Olfactory Bulb Damage

Allergic rhinitis (AR) is a widespread disease that is frequently comorbid with depression. However, the mechanisms and treatments for depression in AR remain underexplored. Metformin, a widely used antidiabetic drug, has shown antidepressant effects. The aim of this study was to explore the effects and potential mechanisms of metformin on depression-like behaviors in an AR mouse model. In the present study, mice were sensitized and challenged with ovalbumin (OVA) to induce AR. Results showed that mice with AR exhibited significant depression-like behavior which was attenuated by metformin. In addition, the levels of expression of synaptic plasticity markers (anti-microtubule-associated protein 2, synaptophysin, postsynaptic density protein 95), neurogenesis markers (doublecortin and Ki-67), and brain-derived neurotrophic factor were decreased in the olfactory bulb (OB) of mice with AR, while metformin ameliorated all these alterations and reduced apoptosis in the OB of these mice. Furthermore, it enhanced the phosphorylation of AMP-activated kinase (AMPK) and the levels of ten-eleven translocation 2 (TET2) and 5-hydroxymethylcytosine in the OB. In conclusion, our findings suggest that metformin might be a viable strategy for treating AR-related depression, possibly by modulating neuroplasticity, neurogenesis, apoptosis, and BDNF signaling in the OB via the AMPK/TET2 pathway.

Metformin exhibits antineoplastic effects on Pten-deficient endometrial cancer by interfering with TGF-β and p38/ERK MAPK signalling

Metformin is a widespread antidiabetic agent that is commonly used as a treatment against type 2 diabetes mellitus patients. Regarding its therapeutic potential, multiple studies have concluded that Metformin exhibits antineoplastic activity on several types of cancer, including endometrial carcinoma. Although Metformin's antineoplastic activity is well documented, its cellular and molecular anticancer mechanisms are still a matter of controversy because a plethora of anticancer mechanisms have been proposed for different cancer cell types. In this study, we addressed the cellular and molecular mechanisms of Metformin's antineoplastic activity by using both in vitro and in vivo studies of Pten-loss driven carcinoma mouse models. In vivo, Metformin reduced endometrial neoplasia initiated by Pten-deficiency. Our in vitro studies using Pten-deficient endometrial organoids focused on both cellular and molecular levels in Metformin's tumor suppressive action. At cellular level, we showed that Metformin is involved in not only the proliferation of endometrial epithelial cells but also their regulation via a variety of mechanisms of epithelial-to-mesenchymal transition (EMT) as well as TGF-β-induced apoptosis. At the molecular level, Metformin was shown to affect the TGF-β signalling., a widely known signal that plays a pivotal role in endometrial carcinogenesis. In this respect, Metformin restored TGF-β-induced apoptosis of Pten-deficient endometrial organoids through a p38-dependent mechanism and inhibited TGF-β-induced EMT on no-polarized endometrial epithelial cells by inhibiting ERK/MAPK signalling. These results provide new insights into the link between the cellular and molecular mechanism for Metformin's antineoplastic activity in Pten-deficient endometrial cancers.

An AMPK agonist suppresses the progress of colorectal cancer by regulating the polarization of TAM to M1 through inhibition of HIF-1α and mTOR signal pathway

OBJECTIVE

This study aimed to evaluate the impact of an adenosine monophosphate-activated protein kinase (AMPK) agonist, metformin (MET), on the antitumor effects of macrophages and to determine the underlying mechanism involved in the process.

MATERIALS AND METHODS

M0 macrophages were derived from phorbol-12-myristate-13-acetate-stimulated THP-1 cells.

RESULTS

The levels of tumor necrosis factor-alpha (TNF-α) and human leukocyte antigen-DR (HLA-DR) were decreased in macrophages incubated with HCT116 cells, whereas those of arginase-1 (Arg-1), CD163, and CD206 were elevated; these effects were reversed by MET. The transfection of small interfering (si) RNA abrogated the influence of MET on the expression of the M1/M2 macrophage biomarkers. MET significantly suppressed the proliferation and migration abilities of HCT116 cells incubated with M0 macrophages; these actions were reversed by siRNA transfection against AMPK. The hypoxia-inducible factor 1-alpha (HIF-1α), phosphorylated protein kinase B (p-AKT), and phosphorylated mammalian target of rapamycin (p-mTOR) levels were reduced by the introduction of MET and promoted by siRNA transfection against AMPK. In addition, the levels of HIF-1α, p-AKT, and p-mTOR suppressed by MET were markedly increased following the transfection of siRNA against AMPK.

CONCLUSION

These findings indicate that MET can repress the progression of colorectal cancer by transforming tumor-associated macrophages to the M1phenotype via inhibition of the HIF-1α and mTOR signaling pathways.

Metformin mediates MicroRNA-21 regulated circulating matrix metalloproteinase-9 in diabetic nephropathy: an in-silico and clinical study

Metformin is commonly used as an oral hypoglycaemic agent in type 2 diabetes mellitus (T2DM). MicroRNA-21 is widely studied in diabetic and diabetic nephropathy (DN) patients. Matrix metalloproteinase-9 (MMP9) is involved in extracellular matrix degradation and tissue repair processes. However, the effect of metformin administration on hsa-miR-21-5p and MMP9 has not been evaluated in T2DM and DN patients. The study subjects were divided into three groups (Healthy controls = 36, T2DM = 38, DN = 35). Anthropometric measurements were taken and biochemical tests were carried out on fasting blood samples. Reverse transcriptase PCR was employed for whole blood gene expression analysis of hsa-miR-21-5p and MMP9. Bioinformatics analyses including drug-gene interaction, protein-protein interaction, functional enrichment analyses and co-expression networks were performed. In the present study, MMP9 and hsa-miR-21-5p levels were downregulated and upregulated respectively in T2DM and DN patients when compared with healthy controls. However, in metformin-treated group, a downregulation of hsa-miR-21-5p and upregulation of MMP9 was observed. In-silico analysis revealed the target genes involved in the miR-21 and MMP9 interaction network. Metformin directly targets miR-21 and regulates MMP9 expression in T2DM patients, influencing the pathogenesis of DN.HighlightsMMP-9 and hsa-miR-21-5p were downregulated and upregulated respectively in T2DM and DN patients in a Western Indian population.The patients treated with metformin showed downregulation of hsa-miR-21-5p and upregulation of MMP9.In-silico analysis revealed MMP-9 as well as PTEN to be targets of hsa-miR-21-5p.Metformin regulates MMP9 expression in T2DM and DN patient populations through hsa-miR-21-5p.

[Protective effect of metformin on pulmonary fibrosis caused by paraquat through activating AMP-activated protein kinase pathway]

OBJECTIVE

To observe whether metformin (MET) inhibits transforming growth factor-β1 (TGF-β1)/Smad3 signaling pathway by activating adenosine activated protein kinase (AMPK), so as to alleviate the pulmonary fibrosis caused by paraquat (PQ) poisoning in mice.

METHODS

Male C57BL/6J mice were randomly divided into the Control group, PQ poisoning model group (PQ group), MET intervention group (PQ+MET group), AMPK agonist group (PQ+AICAR group), and AMPK inhibitor group (PQ+MET+CC group), according to a random number table method. A mouse model of PQ poisoning was established by one-time peritoneal injection of 1 mL PQ solution (20 mg/kg). The Control group was injected with the same volume of normal saline. After 2 hours of modeling, the PQ+MET group was given 2 mL of 200 mg/kg MET solution by gavage, the PQ+AICAR group was given 2 mL of 200 mg/kg AICAR solution by intraperitoneal injection, the PQ+MET+CC group was given 2 mL of 200 mg/kg MET solution by gavage and then 1 mL complex C (CC) solution (20 mg/kg) was intraperitoneally injected, the Control group and PQ group were given 2 mL of normal saline by gavage. The intervention was given once a day for 21 consecutive days. The 21-day survival rate of ten mice in each group was calculated, and the lung tissues of remaining mice were collected at 21 days after modeling. The pathological changes of lung tissues were observed under light microscope after hematoxylin-eosin (HE) staining and Masson staining, and the degree of pulmonary fibrosis was evaluated by Ashcroft score. The content of hydroxyproline in lung tissue and oxidative stress indicators such as malondialdehyde (MDA) and superoxide dismutase (SOD) were detected. The protein expressions of E-cadherin, α-smooth muscle actin (α-SMA), phosphorylated AMPK (p-AMPK), TGF-β1 and phosphorylated Smad3 (p-Smad3) in lung tissue were detected by Western blotting.

RESULTS

Compared with the Control group, the 21 days survival rate was significantly reduced, lung fibrosis and Ashcroft score were significantly increased in PQ group. In addition, the content of hydroxyproline, MDA and the protein expressions of α-SMA, TGF-β1 and p-Smad3 in lung tissue were significantly increased, while the activity of SOD and the protein expressions of E-cadherin and p-AMPK were significantly decreased in PQ group. Compared with the PQ group, the 21 days survival rates of mice were significantly improved in the PQ+MET group and PQ+AICAR group (70%, 60% vs. 20%, both P < 0.05). The degree of pulmonary fibrosis and the Ashcroft score were significantly reduced (1.50±0.55, 2.00±0.63 vs. 6.67±0.52, both P < 0.05). The content of hydroxyproline and MDA in lung tissue, as well as α-SMA, TGF-β1 and p-Smad3 protein expressions were significantly reduced [hydroxyproline (mg/L): 2.03±0.11, 3.00±0.85 vs. 4.92±0.65, MDA (kU/g): 2.06±1.48, 2.10±1.80 vs. 4.06±1.33, α-SMA/GAPDH: 0.23±0.06, 0.16±0.06 vs. 1.00±0.09, TGF-β1/GAPDH: 0.28±0.03, 0.53±0.05 vs. 0.92±0.06 p-Smad3/GAPDH: 0.52±0.04, 0.69±0.06 vs. 1.11±0.10, all P < 0.05], SOD activity and the protein expressions of E-cadherin and p-AMPK were significantly increased [SOD (μmol/g): 39.76±1.35, 33.03±1.28 vs. 20.08±1.79, E-cadherin/GAPDH: 0.91±0.08, 0.72±0.08 vs. 0.26±0.04, p-AMPK/GAPDH: 0.62±0.04, 0.60±0.01 vs. 0.20±0.04, all P < 0.05]. However, these protective effects of MET were inhibited by the addition of AMPK inhibitor CC solution.

CONCLUSIONS

MET can effectively alleviate the degree of pulmonary fibrosis in mice poisoned with PQ, and its mechanism may be related to the activation of AMPK and inhibition of TGF-β1/Smad3 signaling pathway, which can be inhibited by AMPK inhibitor CC.

Metformin attenuates inflammation and boosts autophagy in the liver and intestine of chronologically aged rats

BACKGROUND

Our previous studies found that autophagy levels in liver and intestinal segments of naturally aging rats were downregulated, and the expression of pro-inflammatory factors was increased. The increased expression of pro-inflammatory factors might be related to the downregulation of autophagy. AMPK is the most critical upstream targeting and regulating molecule of autophagy, and Metformin, as an agonist of AMPK, has the effects of anti-inflammation and anti-aging. We pretreated 29-month-old naturally aging rats with Metformin for a short period and observed the changes in autophagy levels and pro-inflammatory factors in the liver, ileum, and colon after 31 days of intervention and preliminarily investigated the mechanism of its action.

METHODS

29-month-old SPF male Wistar rats were divided into three groups: The control group, the Metformin 100 mg/kg intervention group, and the Metformin 250 mg/kg intervention group, with eight rats in each group. At 29 months, different concentrations of Metformin (100 mg/kg, 250 mg/kg) were given by gavage once a day until 30 months, and the control group was kept generally until 30 months. Western Blot was used to assess the expression levels of AMPK, P-AMPK, LC3, and P62 proteins in the liver and intestinal tissues. Intestinal and liver tissues were immunofluorescence labeled for LC3 and P62 proteins. Moreover, RT-qPCR was conducted to detect the expression levels of pro-inflammatory factors IL-1β, TNF-α, IL-6, and MMP-9 mRNA in liver and intestinal tissues.

RESULTS

Short-term Metformin pretreatment (31 days) in naturally aging rats (29 months old) increased autophagy levels and down-regulated the expression of various pro-inflammatory cytokines (IL-1β, TNF-α, MMP-9, and IL-6) in various intestinal segments and the liver-the expression of LC3II protein enriched with the increase of Metformin concentration. The level of P62 protein decreased with the accumulation of Metformin concentration. And a higher concentration of Metformin was associated with increased expression of P-AMPK protein.

CONCLUSIONS

Metformin intervention can boost the autophagy level in the liver and intestine and reduce the expression of aging-related inflammatory factors in aged rats, and these effects may be related to the increase of the AMPK phosphorylation level.

Anti-hyperglycemic effects of propolis or metformin in type 2 diabetes mellitus

Background: The aim of this study was to evaluate the effect of propolis or metformin versus placebo on glycemic control in pharmacological treatment-naïve patients with type 2 diabetes mellitus (T2DM). Methods: A double-blind, randomized, placebo-controlled in parallel groups clinical trial was performed in 36 pharmacological treatment-naïve patients with T2DM. They received propolis (300 mg), metformin (850 mg), or placebo twice daily before breakfast and dinner for 12 weeks. At the beginning and end of the study, fasting plasma glucose (FPG), 2-h postload glucose (2-h PG) during a 75-g oral glucose tolerance test, glycated hemoglobin A1c (A1C) and a metabolic profile were measured. Areas under the curve (AUC) of glucose and insulin, total insulin secretion (insulinogenic index), the first phase of insulin secretion (Stumvoll index), and insulin sensitivity (Matsuda index) were calculated. Statistical analyses: Kruskal-Wallis, Mann-Whitney U and Wilcoxon tests. Results: The propolis and metformin groups exhibited significant reductions in FPG (p=0.009 and p=0.001, respectively), 2-h PG (p=0.034 and p=0.001, respectively) levels, AUC of insulin, Stumvoll index, and an increment in the Matsuda index. The comparison of the changes from baseline to the end showed significant differences between placebo and propolis in FPG (p=0.004) and A1C (p=0.049) levels, while between placebo and metformin were in FPG (p=0.002), 2-h PG (p=0.004) and A1C (p=0.007) levels. Conclusions: The administration of propolis and metformin compared to placebo reduced FPG and A1C levels; in addition, metformin decreased 2-h PG, AUC of glucose and insulin, high-density lipoprotein cholesterol, and increased the insulin sensitivity.

Vitamin D3 alleviates lung fibrosis of type 2 diabetic rats via SIRT3 mediated suppression of pyroptosis

PURPOSE

We aimed to evaluate whether pulmonary fibrosis occurs in type 2 diabetes rat models and whether VD3 can prevent it by inhibiting pyroptosis.

METHODS

Sprague-Dawley rats were assigned to normal control (NC), diabetic model control (MC), low-dose VD3 (LVD), medium-dose VD3 (MVD), high-dose VD3 (HVD) and metformin positive control (PC) groups. Type 2 diabetes model was induced by a high-sugar, high-fat diet combined with STZ injection, and subsequently intervened with VD3 or metformin for 10 weeks. Blood glucose, body weight, food intake, water intake, urine volume, morphology, lung hydroxyproline level, immunohistochemistry, TUNEL staining, inflammatory cytokines secretion and related protein expression were analyzed.

RESULTS

Diabetic rats exhibited significant impairments in fasting blood glucose, insulin resistance, body weight, food intake, water intake, and urine volume. While morphological parameters, diabetic rats exhibited severe lung fibrosis. Intriguingly, VD3 intervention reversed, at least in part, the diabetes-induced alterations. The expression of pyroptosis-related proteins was up-regulated in diabetic lungs whereas the changes were reversed by VD3. In the meanwhile, SIRT3 expression was down-regulated in diabetic lungs while VD3 up-regulated it.

CONCLUSION

Fibrotic changes were observed in diabetic rat lung tissue and our study indicates that VD3 may effectively ameliorate diabetic pulmonary fibrosis via SIRT3-mediated suppression of pyroptosis.

Metformin Versus Insulin for Gestational Diabetes: Cognitive and Neuropsychological Profiles of Children Aged 9 years

OBJECTIVE

We compared cognitive profile and neuropsychological performance in 9-year-old offspring of mothers who were treated with metformin or insulin for gestational diabetes mellitus (GDM).

METHODS

A total of 172 children whose mothers were randomly assigned to receive either metformin or insulin for GDM were studied at the age of 9 years. Of these children, 127 were from Turku, Finland (63 metformin and 64 insulin), and 45 from Oulu, Finland (19 metformin and 26 insulin). Clinical and demographic background characteristics were obtained at enrolment, birth, and 9-year follow-up. Cognitive profiles were examined at age 9 years with the Wechsler Intelligence Scale for Children. Neuropsychological functions were examined with 2 subtests of the Developmental Neuropsychological Assessment test battery assessing comprehension of instructions and narrative memory, Trail Making Test assessing attention and with Behavioral Rating Inventory of Executive Functioning, including parent-rated and teacher-rated evaluations. Academic functioning was studied with reading fluency subtest of the Screening test for reading, writing, and calculus for first to sixth grades and information about educational support received at school reported by parents.

RESULTS

The cognitive profiles, including indexes of verbal comprehension, perceptual reasoning, working memory, and processing speed, did not differ significantly between metformin-treated and insulin-treated groups. Significant differences were not found between the treatment groups in assessed neuropsychological functions, reading fluency, or received level of support at school.

CONCLUSION

Cognitive and neuropsychological outcomes were similar in 9-year-old children whose mothers had either metformin or insulin treatment of GDM.

Effects of pioglitazone and linagliptin on glycemic control, lipid profile and hs-CRP in metformin-treated patients with type 2 diabetes: a comparative study

OBJECTIVES

The purpose of this study was to compare the effects of pioglitazone and linagliptin on glycemic control, lipid profile and high-sensitivity C-reactive protein (hs-CRP) parameters in patients with type 2 diabetes treated with metformin.

METHODS

The present randomized clinical trial was conducted on 60 patients with type 2 diabetes treated with metformin in the age range of 30-60 years. The participants with informed consent were randomly assigned to receive pioglitazone or linagliptin. The first intervention group (n=30) received 30 mg of pioglitazone daily and the second intervention group (n=30) received 5 mg of linagliptin daily for 12 weeks. Fasting blood samples were taken from patients at the baseline and after 12 weeks to measure related variables. The current study was approved in Kashan University of Medical Sciences (with the code of ethics of IR.KAUMS.MEDNT.REC.1398.016), and the Iranian Registry of Clinical Trials (with the registration number of IRCT20170513033941N66).

RESULTS

The linagliptin administration significantly reduced serum levels of fasting blood sugar (p=0.03), blood sugar 2 h after a meal (p=0.02), glycosylated hemoglobin (p=0.02) and hs-CRP (p=0.005) after 12 weeks compared with pioglitazone. In contrast, the pioglitazone administration significantly decreased triglyceride levels (p=0.01) and increased HDL-cholesterol (p=0.002) compared to linagliptin. In addition, the administration of both linagliptin and pioglitazone drugs had no significant effect on LDL-cholesterol, total cholesterol, systolic and diastolic blood pressure, creatinine and blood urea.

CONCLUSIONS

The present study demonstrated the superiority of linagliptin over pioglitazone for glycemic control, although pioglitazone compared to linagliptin showed greater efficacy in reducing triglycerides and raising HDL-cholesterol.

Metformin inhibits digestive proteases and impairs protein digestion in mice

Metformin is among the most prescribed medications worldwide and the first-line therapy for type 2 diabetes. However, gastrointestinal side effects are common and can be dose limiting. The total daily metformin dose frequently reaches several grams, and poor absorption results in high intestinal drug concentrations. Here, we report that metformin inhibits the activity of enteropeptidase and other digestive enzymes at drug concentrations predicted to occur in the human duodenum. Treatment of mouse gastrointestinal tissue with metformin reduces enteropeptidase activity; further, metformin-treated mice exhibit reduced enteropeptidase activity, reduced trypsin activity, and impaired protein digestion within the intestinal lumen. These results indicate that metformin-induced protein maldigestion could contribute to the gastrointestinal side effects and other impacts of this widely used drug.

Salsalate and/or metformin therapy confer beneficial metabolic effects in olanzapine treated female mice

Antipsychotic medications are used in the management of schizophrenia and a growing number of off-label conditions. While effective at reducing psychoses, these drugs possess noted metabolic side effects including weight gain, liver lipid accumulation and disturbances in glucose and lipid metabolism. To counter the side effects of antipsychotics standard of care has typically included metformin. Unfortunately, metformin does not protect against antipsychotic induced metabolic disturbances in all patients and thus additional treatment approaches are needed. One potential candidate could be salsalate, the prodrug of salicylate, which acts synergistically with metformin to improve indices of glucose and lipid metabolism in obese mice. The purpose of the current investigation was to compare the effects of salsalate, metformin and a combination of both drugs, on weight gain and indices of metabolic health in female mice treated with the antipsychotic, olanzapine. Herein we demonstrate that salsalate was equally as effective as metformin in protecting against olanzapine induced weight gain and liver lipid accumulation with no additional benefit of combining both drugs. Conversely, metformin treatment, either alone or in combination with salsalate, improved indices of glucose metabolism and increased energy expenditure in olanzapine treated mice. Collectively, our findings provide evidence that dual therapy with both metformin and salsalate could be an efficacious approach with which to dampen the metabolic consequences of antipsychotic medications.

Metformin and Trehalose-Modulated Autophagy Exerts a Neurotherapeutic Effect on Parkinson's Disease

Since the number of aged people will increase in the next years, neurodegenerative diseases, including Parkinson's Disease (PD), will also rise. Recently, we demonstrated that autophagy stimulation with rapamycin decreases dopaminergic neuronal death mediated by oxidative stress in the paraquat (PQ)-induced PD model. Assessing the neurotherapeutic efficacy of autophagy-inducing molecules is critical for preventing or delaying neurodegeneration. Therefore, we evaluated the autophagy inducers metformin and trehalose effect in a PD model. Autophagy induced by both molecules was confirmed in the SH-SY5Y dopaminergic cells by detecting increased LC3-II marker and autophagosome number compared to the control by western blot and transmission electron microscopy. Both autophagy inducers showed an antioxidant effect, improved mitochondrial activity, and decreased dopaminergic cell death induced by PQ. Next, we evaluated the effect of both inducers in vivo. C57BL6 mice were pretreated with metformin or trehalose before PQ administration. Cognitive and motor deteriorated functions in the PD model were evaluated through the nest building and the gait tests and were prevented by metformin and trehalose. Both autophagy inducers significantly reduced the dopaminergic neuronal loss, astrocytosis, and microgliosis induced by PQ. Also, cell death mediated by PQ was prevented by metformin and trehalose, assessed by TUNEL assay. Metformin and trehalose induced autophagy through AMPK phosphorylation and decreased α-synuclein accumulation. Therefore, metformin and trehalose are promising neurotherapeutic autophagy inducers with great potential for treating neurodegenerative diseases such as PD.

Gallic acid improves the metformin effects on diabetic kidney disease in mice

OBJECTIVES

Metformin is an antidiabetic agent that is used as the first-line treatment of type 2 diabetes mellitus. Gallic acid is a type of phenolic acid that has been shown to be a potential drug candidate to treat diabetic kidney disease, an important complication of diabetes. We aimed to test whether a combination of gallic acid and metformin can exert synergetic effect on diabetic kidney disease in diabetic mice model.

METHODS

Streptozotocin (65 mg/kg) intraperitoneal injection was used to induce diabetic kidney disease in mice. The diabetic mice were treated with saline (Vehicle), gallic acid (GA) (30 mg/kg), metformin (MET) (200 mg/kg), or the combination of gallic acid (30 mg/kg) and metformin (200 mg/kg) (GA + MET).

RESULTS

Our results demonstrated that compared to the untreated diabetic mice, all three strategies (GA, MET, and GA + MET) exhibited various effects on improving renal morphology and functions, reducing oxidative stress in kidney tissues, and restoring AMP-activated protein kinase (AMPK)/silent mating type information regulation 2 homolog 1 (SIRT1) signaling in kidney tissues of diabetic mice. Notably, the combination strategy (GA + MET) provided the most potent renal protection effects than any single strategies (GA or MET).

CONCLUSION

Our results support the hypothesis that gallic acid might serve as a potential supplement to metformin to enhance the therapeutical effect of metformin.

Integration of metabolomics and transcriptomics reveals metformin suppresses thyroid cancer progression via inhibiting glycolysis and restraining DNA replication

The anti-tumoral effects of metformin have been widely studied in several types of cancer, including thyroid cancer; however, the underlying molecular mechanisms remain poorly understood. As an oral hypoglycemic drug, metformin facilitates glucose catabolism and disrupts metabolic homeostasis. Metabolic reprogramming, particularly cellular glucose metabolism, is an important characteristic of malignant tumors. This study aimed to explore the therapeutic effects of metformin in thyroid cancer and the underlying metabolic mechanism. In the present study, it was shown that metformin reduced cell viability, invasion, migration, and EMT, and induced apoptosis and cell cycle G1 phase arrest in thyroid cancer. Transcriptome analysis demonstrated that the differentially expressed genes induced by metformin were involved in several signaling pathways including apoptosis singling pathways, TGF-β signaling, and cell cycle regulation in human thyroid cancer cell lines. In addition, the helicase activity of the CDC45-MCM2-7-GINS complex and DNA replication related genes such as RPA2, RAD51, and PCNA were downregulated in metformin-treated thyroid cancer cells. Moreover, metabolomics analysis showed that metformin-induced significant alterations in metabolic pathways such as glutathione metabolism and polyamine synthesis. Integrative analysis of transcriptomes and metabolomics revealed that metformin suppressed glycolysis by downregulating the key glycolytic enzymes LDHA and PKM2 and upregulating IDH1 expression in thyroid cancer. Furthermore, the anti-tumor role of metformin in thyroid cancer in vivo was shown. Together these results show that metformin plays an anti-tumor role by inhibiting glycolysis and restraining DNA replication in thyroid cancer.

New insights on the potential anti-epileptic effect of metformin: Mechanistic pathway

Epilepsy is a chronic neurological disease characterized by recurrent seizures. Epilepsy is observed as a well-controlled disease by anti-epileptic agents (AEAs) in about 69%. However, 30%-40% of epileptic patients fail to respond to conventional AEAs leading to an increase in the risk of brain structural injury and mortality. Therefore, adding some FDA-approved drugs that have an anti-seizure activity to the anti-epileptic regimen is logical. The anti-diabetic agent metformin has anti-seizure activity. Nevertheless, the underlying mechanism of the anti-seizure activity of metformin was not entirely clarified. Henceforward, the objective of this review was to exemplify the mechanistic role of metformin in epilepsy. Metformin has anti-seizure activity by triggering adenosine monophosphate-activated protein kinase (AMPK) signalling and inhibiting the mechanistic target of rapamycin (mTOR) pathways which are dysregulated in epilepsy. In addition, metformin improves the expression of brain-derived neurotrophic factor (BDNF) which has a neuroprotective effect. Hence, metformin via induction of BDNF can reduce seizure progression and severity. Consequently, increasing neuronal progranulin by metformin may explain the anti-seizure mechanism of metformin. Also, metformin reduces α-synuclein and increases protein phosphatase 2A (PPA2) with modulation of neuroinflammation. In conclusion, metformin might be an adjuvant with AEAs in the management of refractory epilepsy. Preclinical and clinical studies are warranted in this regard.

EGR1-mediated metabolic reprogramming to oxidative phosphorylation contributes to ibrutinib resistance in B-cell lymphoma

The use of Bruton tyrosine kinase inhibitors, such as ibrutinib, to block B-cell receptor signaling has achieved a remarkable clinical response in several B-cell malignancies, including mantle cell lymphoma (MCL) and diffuse large B-cell lymphoma (DLBCL). Acquired drug resistance, however, is significant and affects the long-term survival of these patients. Here, we demonstrate that the transcription factor early growth response gene 1 (EGR1) is involved in ibrutinib resistance. We found that EGR1 expression is elevated in ibrutinib-resistant activated B-cell-like subtype DLBCL and MCL cells and can be further upregulated upon ibrutinib treatment. Genetic and pharmacological analyses revealed that overexpressed EGR1 mediates ibrutinib resistance. Mechanistically, TCF4 and EGR1 self-regulation induce EGR1 overexpression that mediates metabolic reprogramming to oxidative phosphorylation (OXPHOS) through the transcriptional activation of PDP1, a phosphatase that dephosphorylates and activates the E1 component of the large pyruvate dehydrogenase complex. Therefore, EGR1-mediated PDP1 activation increases intracellular adenosine triphosphate production, leading to sufficient energy to enhance the proliferation and survival of ibrutinib-resistant lymphoma cells. Finally, we demonstrate that targeting OXPHOS with metformin or IM156, a newly developed OXPHOS inhibitor, inhibits the growth of ibrutinib-resistant lymphoma cells both in vitro and in a patient-derived xenograft mouse model. These findings suggest that targeting EGR1-mediated metabolic reprogramming to OXPHOS with metformin or IM156 provides a potential therapeutic strategy to overcome ibrutinib resistance in relapsed/refractory DLBCL or MCL.

Metformin Regulates the miR-205/VEGFA Axis in Renal Cell Carcinoma Cells: Exploring a Clinical Synergism with Tyrosine Kinase Inhibitors

INTRODUCTION

Metformin (MF) intake could be associated with a favorable outcome in sunitinib (SUT)- and axitinib (AX)-treated clear cell renal cell carcinoma (ccRCC) patients. Functionally, MF induces miR-205, a microRNA serving as a tumor suppressor in several cancers.

METHODS

Real-time quantitative PCR, viability assays, and Western blotting analyzed MF and SUT/AX effects in RCC4 and 786-O cells. A tetracycline-inducible overexpression model was used to study the role of miR-205 and its known target gene, VEGFA. We analyzed miR-205 and VEGFA within a public and an in-house ccRCC cohort. Human umbilical vein endothelial cell (HUVEC) sprouting assays examined miR-205 effects on angiogenesis initiation. To determine the influence of the von Hippel-Lindau tumor suppressor (VHL), we examined VHLwt reexpressing RCC4 and 786-O cells.

RESULTS

Viability assays confirmed a sensitizing effect of MF toward SUT/AX in RCC4 and 786-O cells. Overexpression of miR-205 diminished VEGFA expression - as did treatment with MF. Tumor tissue displayed a downregulation of miR-205 and an upregulation of VEGFA. Accordingly, miR-205 caused less and shorter vessel sprouts in HUVEC assays. Finally, VHLwt-expressing RCC4 and 786-O cells displayed higher miR-205 and lower VEGFA levels.

CONCLUSION

Our results support the protective role of MF in ccRCC and offer functional insights into the clinical synergism with tyrosine kinase inhibitors.

Predictors of HbA1c treatment response to add-on medication following metformin monotherapy: a population-based cohort study

Evidence on the influence of patient characteristics on HbA1c treatment response for add-on medications in patients with type 2 diabetes (T2D) is unclear. This study aims to investigate the predictors of HbA1c treatment response for three add-on medications (sulfonylureas (SU), dipeptidyl peptidase-4 (DPP-4) and sodium-glucose cotransporter-2 (SGLT-2) inhibitor) in metformin monotherapy treated patients with T2D. This retrospective cohort study was conducted using the electronic health record data from six primary care clinics in Singapore. A total of 9748 adult patients with T2D on metformin monotherapy receiving SU, DPP-4 or SGLT-2 add-on were 1:1 propensity score matched to patients receiving other add-on medications. Patient demographics, laboratory results, diabetes related complications, comedications, and treatment response at two endpoints (HbA1c reduction ≥ 1% at 6th month, HbA1c goal attainment < 7% at 12th month) were examined. Multiple logistic regression analyses were used to identify patient characteristics associated with the treatment responses. After matching, there were 1073, 517, and 290 paired cohorts of SU, DPP-4 and SGLT-2 respectively. Besides baseline HbA1c, patients with longer hypertension disease duration and higher cholesterol HDL were associated with better treatment response to SU medication add-on. Lower estimated glomerular filtration rate (eGFR), and angiotensin-II receptor medications were associated with better treatment response to DPP-4 add-on. Lower cholesterol HDL, higher creatinine serum, absence of renal complications and beta-blockers medications were associated with better treatment response to SGLT-2 add-on. The cholesterol HDL, creatinine serum, eGFR, hypertension disease duration, angiotensin-II receptors and beta-blockers class of medications can influence the HbA1c treatment response for SU, DPP-4 and SGLT-2 add-on medications. Knowing the patients' characteristics that influence treatment response can assist in guiding clinical decisions when selecting the appropriate add-on medication, ultimately helping to prevent the development of diabetes-related complications.

Metformin Prevents Cocaine Sensitization: Involvement of Adenosine Monophosphate-Activated Protein Kinase Trafficking between Subcellular Compartments in the Corticostriatal Reward Circuit

Repeated cocaine exposure produces an enhanced locomotor response (sensitization) paralleled by biological adaptations in the brain. Previous studies demonstrated region-specific responsivity of adenosine monophosphate-activated protein kinase (AMPK) to repeated cocaine exposure. AMPK maintains cellular energy homeostasis at the organismal and cellular levels. Here, our objective was to quantify changes in phosphorylated (active) and total AMPK in the cytosol and synaptosome of the medial prefrontal cortex, nucleus accumbens, and dorsal striatum following acute or sensitizing cocaine injections. Brain region and cellular compartment selective changes in AMPK and pAMPK were found with some differences associated with acute withdrawal versus ongoing cocaine treatment. Our additional goal was to determine the behavioral and molecular effects of pretreatment with the indirect AMPK activator metformin. Metformin potentiated the locomotor activating effects of acute cocaine but blocked the development of sensitization. Sex differences largely obscured any protein-level treatment group effects, although pAMPK in the NAc shell cytosol was surprisingly reduced by metformin in rats receiving repeated cocaine. The rationale for these studies was to inform our understanding of AMPK activation dynamics in subcellular compartments and provide additional support for repurposing metformin for treating cocaine use disorder.