Effect Of Metformin In Combination Research Articles

Combination of Metformin and Epigallocatechin-3-Gallate Lowers Cortisol, 11β-Hydroxysteroid Dehydrogenase Type 1, and Blood Glucose Levels in Sprague Dawley Rats with Obesity and Diabetes.

The combined effects of metformin and epigallocatechin-3-gallate (EGCG) on cortisol, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), and blood glucose levels have not been investigated. This study evaluated the effectiveness of combining EGCG with metformin in regulating those levels in a rat model of diet-induced diabetes and obesity. Thirty diabetic and obese rats on a high-fat diet were treated daily for 28 days with EGCG (100 mg/kg of body weight/day), metformin (200 mg/kg of body weight/day), or both. Control groups comprised lean rats, untreated obese diabetic rats, and metformin-only-treated rats. Blood samples were collected to measure cortisol and fasting blood glucose (FBG) levels and liver tissue samples were examined for 11β-HSD1 levels. Rats receiving combination therapy had significantly reduced cortisol levels (from 36.70±15.13 to 31.25±7.10 ng/mL) compared with the untreated obese diabetic rats but not the rats receiving monotherapy. Rats receiving combination therapy and EGCG monotherapy had significantly lower 11β-HSD1 levels compared with the untreated obese diabetic rats (92.68±10.82 and 93.74±18.11 ng/L vs. 120.66±14.00 ng/L). Combination therapy and metformin monotherapy significantly reduced FBG levels (440.83±133.30 to 140.50±7.36 mg/dL and 480.67±86.32 to 214.17±102.78 mg/dL, respectively) by approximately 68.1% and 55.4% compared with rats receiving EGCG monotherapy and untreated obese diabetic rats. Combining EGCG with metformin exhibited synergistic effects compared with monotherapy for managing diabetes, leading to improved outcomes in reduction of baseline cortisol levels along with reduction in 11β-HSD1 and blood glucose levels.

Metformin enhances the anti-tumor effects mediated by attenuated Salmonella typhimurium

In bacterial-based cancer therapy, while attenuated Salmonella treatment effectively inhibits tumor progression, single bacterial therapy struggles to completely suppress tumor growth and metastasis. Metformin, a natural compound derived from Galega officinalis L. and known for its antidiabetic properties, also demonstrates significant anti-tumor activity. However, the combined effect of metformin and attenuated Salmonella on tumor treatment has not been thoroughly investigated. In this study, we observed that metformin enhances attenuated Salmonella-mediated recruitment of tumor-infiltrating immune cells, such as NK cells, neutrophils, M1 macrophages, CD4+, and CD8+T lymphocytes in CT26 tumor-bearing mice. Furthermore, the combined treatment of metformin and attenuated Salmonella increases the protein expression of PEN2, PD1, and PD-L1. This finding is likely associated with the enhanced anti-tumor effects of S.t ΔppGpp by metformin, indicating that the combination of S.t ΔppGpp and metformin holds promise as a synergistic strategy for attenuated Salmonella-based immunotherapy.

Abstract P423: Individual and Combined Effects of Diet, Exercise, and Metformin on Risk of Microvascular Complications in Older Type 2 Diabetes Patients: Post-Hoc Analysis of Action to Control Cardiovascular Risk in Diabetes (ACCORD) Trial Data

Introduction: Microvascular complications are a major burden on the health of type 2 diabetes (T2D) patients. The literature has yielded mixed results regarding synergistic effects of common diabetes treatments (i.e., metformin, exercise, and diet) on microvascular complication risk. Some trials demonstrated that the combination of metformin and exercise diminished beneficial effects. We aimed to explore this ambiguity in findings by examining the effects of metformin, exercise, and diet on microvascular complication risk over time among T2D patients in the U.S. and Canada. Hypothesis: We hypothesize that the combined effects of metformin, exercise, and diet would be better than their individual effects on microvascular complication risk. Methods: We analyzed data from 923 participants [mean age: 62.6; 39.2% female; mean years with diabetes: 10.7] of the Action to Control Cardiovascular Risk in Diabetes (ACCORD) (2003-2009) trial. Adequate exercise was defined as > 150 mins of moderate-intensity physical activity per week. Metformin use was defined as yes vs. no. An adequate diet score was ≤ 2.4 of the summary fat intake score (range: 0 - 5). We defined composite outcomes for microvascular complications (i.e., nephropathy, retinopathy, and neuropathy) based on several measurements including serum creatinine doubling, decrease in estimated glomerular filtration ratio (≥ 20 ml/min/1.73 m2 decrease), vision loss, Michigan Neuropathy Screening Instrument. We performed longitudinal analysis with synergy factor (SF) approach using multinomial logistic regression models adjusted for sex, diabetes years, education, alcohol, treatment arm, and baseline outcome. Results: Among individuals with poor diet score, those taking metformin but not adequate exercise had an odds ratio of 1.12 (95% CI: 0.65 - 1.94, p = 0.68) for microvascular complication. Those not taking metformin but had adequate exercise had an odds ratio of 2.71 (95% CI: 1.12 - 6.59, p < 0.05). However, taking metformin and having adequate exercise produced an odds ratio of 0.90 (95% CI: 0.49 - 1.67, p = 0.75), which was 0.30 times less than the predicted odds of the joint effect (SF = 0·30, 95% CI: 0 - 0.59, p = 0·05). Individuals with an adequate diet, adequate exercise, and taking metformin had an odds ratio of 0.85 (95% CI: 0.48 - 1.49, p = 0.57). However, we did not find these associations to be statistically significant. A similar pattern holds for individual microvascular complication outcomes. Conclusion: Additional randomized controlled trials are needed to confirm the potential additive beneficial effect of metformin, adequate exercise, and adequate diet combination over their individual effects on odds of microvascular complications.

Metformin and exercise effects on postprandial insulin sensitivity and glucose kinetics in pre-and-diabetic adults.

The potential interaction between metformin and exercise on glucose-lowering effects remains controversial. We studied the separated and combined effects of metformin and/or exercise on fasting and postprandial insulin sensitivity in individuals with pre- and - type 2 diabetes (T2D). Eight T2D adults (60±4 years) with overweight/obesity (32±4 kg·m-2) under chronic metformin treatment (9±6 years; 1281±524 mg·day-1) underwent four trials; a) taking their habitual metformin treatment (MET), b) substituting during 96 h their metformin medication by placebo (PLAC), c) placebo combined with 50 min bout of high-intensity interval exercise (PLAC+EX), and d) metformin combined with exercise (MET+EX). Plasma glucose kinetics using stable isotopes (6,6-2H2 and [U-13C] glucose), and glucose oxidation by indirect calorimetry, were assessed at rest, during exercise, and in a subsequent oral glucose tolerance test (i.e., OGTT). Postprandial glucose and insulin concentrations were analyzed as mean and incremental area under the curve (iAUC), and insulin sensitivity was calculated (i.e., MATSUDAindex and OGISindex). During OGTT, metformin reduced glucose iAUC (i.e., MET and MET+EX lower than PLAC and PLAC+EX, respectively; P=0.023). MET+EX increased MATSUDAindex above PLAC (4.8±1.4 vs 3.3±1.0, respectively; P=0.018) and OGISindex above PLAC (358±52 vs 306±46 mL·min-1·m-2, respectively; P=0.006). Metformin decreased plasma appearance of the ingested glucose (Ra OGTT; MET vs PLAC, -3.5; 95% CI -0.1 to -6.8 µmol·kg-1·min-1; P=0.043). Metformin combined with exercise potentiates insulin sensitivity during an OGTT in individuals with pre- and - type 2 diabetes. Metformin's blood glucose-lowering effect seems mediated by decreased oral glucose entering the circulation (gut-liver effect) an effect partially blunted after exercise.

Hepatic Steatosis Alleviated by a Novel Metformin and Quercetin Combination Activating Autophagy Through the cAMP/AMPK/SIRT1 Pathway.

Non-alcoholic fatty liver disease (NAFLD) incidence and prevalence are rapidly increasing globally. The combined effects of metformin and quercetin (Que) have yet to be investigated. However, both have demonstrated the potential to reduce triglyceride (TG) levels and treat NAFLD by promoting autophagy. The objective of the present study was to elucidate the mechanism of action and assess the role of autophagy in the lipid-lowering effects of Que, both individually and in combination with metformin, in a HepG2 cell model of hepatic steatosis. Triglyceride levels and lipogenic gene expression were reduced in HepG2 cells exposed to palmitic acid (PA) when treated with Que-metformin, as evidenced by triglyceride measurements and real-time PCR. The LDH release assay also showed that this combination induced autophagy to protect HepG2 cells from PA-induced cell death. According to the Western blot analysis outcomes, Que-metformin increased LC3-I and LC3-II protein levels while decreasing p62 expression to induce autophagy. In HepG2 cells, the co-administration of Que-metformin elevated cAMP, phosphorylated AMP-activated protein kinase (p-AMPK), and Beclin-1 levels. Additionally, the inhibition of SIRT1 reversed the autophagy induced by Que-metformin. The findings of this study demonstrated for the first time that Que-metformin reduced hepatosteatosis by stimulating autophagy through the cAMP/AMPK/SIRT1 signaling pathway and diminishing inflammatory cytokines.

Influence of diabetes mellitus and effectiveness of metformin on hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common cancers, and it is important to elucidate the carcinogenic factors and improve the recurrence and prognosis of HCC patients. Diabetes mellitus (DM) has been reported to be a risk factor for the carcinogenesis of many cancers including HCC, and the mechanism of DM for carcinogenesis is gradually being elucidated. Metformin, a drug for DM, has been reported to have anticancer effects many cancers including HCC. Metformin not only suppresses carcinogenesis but also improves the prognosis of recurrence after treatment, and there are many reports on the mechanism of these effects. In this review, we describe the mechanism of action of hyperglycemia and hyperinsulinemia on carcinogenesis by DM against HCC. The carcinogenic effects of DM on hepatitis B, hepatitis C, and nonalcoholic fatty liver disease (NAFLD) by etiology are also described. In addition, the carcinogenic effect of metformin on HCC and its mechanism of action are reviewed. We also discuss the effects of metformin on recurrence after hepatectomy and radiofrequency therapy and the effects of metformin in combination with anticancer medicine, focusing on the inhibition of HCC development. This article is protected by copyright. All rights reserved.

The combined effect of metformin and mirabegron on diet-induced obesity.

Anti-obesity medications act by suppressing energy intake (EI), promoting energy expenditure (EE), or both. Metformin (Met) and mirabegron (Mir) cause weight loss by targeting EI and EE, respectively. However, anti-obesity effects during concurrent use of both have yet to be explored. In this study, we investigated the anti-obesity effects, metabolic benefits, and underlying mechanisms of Met/Mir combination therapy in two clinically relevant contexts: the prevention model and the treatment model. In the prevention model, Met/Mir caused further 12% and 14% reductions in body weight (BW) gain induced by a high-fat diet compared to Met or Mir alone, respectively. In the treatment model, Met/Mir additively promoted 17% BW loss in diet-induced obese mice, which was 13% and 6% greater than Met and Mir alone, respectively. Additionally, Met/Mir improved glucose tolerance and insulin sensitivity. These benefits of Met/Mir were associated with increased EE, activated brown adipose tissue thermogenesis, and white adipose tissue browning. Significantly, Met/Mir did not cause cardiovascular dysfunction in either model. Together, the combination of Met and Mir could be a promising approach for the prevention and treatment of obesity by targeting both EI and EE simultaneously.

Metformin enhances anti-cancer properties of resveratrol in MCF-7 breast cancer cells via induction of apoptosis, autophagy and alteration in cell cycle distribution

Breast cancer is the fifth leading cause of death, worldwide affecting both genders. Accumulating evidence suggests that metformin, an oral hypoglycemic agent used in the management of type 2 diabetes, exerts anti-tumor effects in many cancers, including the breast cancer. Resveratrol, a natural product found abundantly in many fruits, exhibits marked cytotoxic and pro-oxidant effects.This study was designed to investigate the effect of metformin in combination with resveratrol and cisplatin in MCF-7 cells. Study groups were as follows: untreated control group, single treatment groups (metformin, resveratrol, and cisplatin), double treatment groups (metformin + resveratrol, metformin + cisplatin, and cisplatin + resveratrol) and triple treatment groups (metformin + resveratrol + cisplatin). Our results indicated that metformin inhibits proliferation of MCF-7 cells, an effect that was associated with ROS production and G0/G1 cell cycle arrest, but not apoptosis. Moreover, resveratrol suppressed the proliferation of MCF-7 cells by induction of apoptosis as well as cell cycle arrest. Notably, a significant inhibitory effect in the co-treatment of metformin, resveratrol, and cisplatin was observed which was attributed to induction of autophagy-mediated cell death and apoptosis along cell cycle arrest.In conclusion, our results advocate the anti-cancer properties of metformin and resveratrol on MCF-7 cell s via induction of cell cycle arrest. Additionally, synergistic anti-cancer effects of metformin in a triple combination with cisplatin and resveratrol was attributed to induction of autophagy-mediated cell death and apoptosis along cell cycle arrest. Based on our findings it is proposed that patients may benefit from addition of a drug with a safe profile to conventional anticancer therapies.

Effect of combination of metformin with B12 and folic acid on lipid profile and levels of homocysteine in adult male rabbits

The present study aims to evaluate the effects of metformin in combination with vitamin B12 and folic acid on lipid profiles and serum homocysteine levels in male rabbits. The study included twenty-four male rabbits that weighed (1.5-2 kg), and were divided randomly into four groups (six rabbits/group). The control first group was administrated (5 ml) of distilled water; The second group was given metformin (125g/kg B.W) plus vitamin B12 (500 μg/kg B.W) daily, the third group was given metformin (125g/kg B.W) plus folic acid (5g/kg B.W) daily and the fourth group was given metformin (125g/kg B.W), folic acid (5g/kg B.W) and vitamin B12 (500 μg/kg B.W) daily, the rabbits were followed up for one month. The results revealed a decrease in the final body weight and body weight gain in all treated groups as compared to the control group. The homocysteine parameter decreases significantly in the second group which was given metformin and B12 and the third group was given metformin in combination with folic acid as compared with the control group and group four. It showed a significant decrease in the fourth group (metformin + folic acid + vitamin B12) compared with the second and third groups also the glucose level increased significantly in group three compared to group second, fourth, and control group. The results showed that serum cholesterol and TG have decreased in G2 and G3 while an increase in G4 as compared with the control group, and the HDL was decreased in G2 and G4 compared with control and G3 groups. While the results of LDL and VLDL were increased in G3 and G4 compared with G2 and the control group

Metformin, testosterone, or both in men with obesity and low testosterone: A double-blind, parallel-group, randomized controlled trial

BackgroundMen with obesity tend to be insulin resistant and often have low-normal testosterone concentrations. We conducted a clinical trial aimed to evaluate potential therapeutic strategies for low testosterone in men with obesity. MethodsWe did a 1-year, parallel, randomized, double-blind, placebo-controlled trial, where we evaluated the independent and combined effects of metformin and testosterone in 106 men with obesity, aged 18–50 years, who had low levels of testosterone and no diabetes mellitus. The primary outcome was change in insulin resistance, measured as Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) index. Secondary outcomes included changes in total and free serum testosterone, body composition, metabolic variables, erectile function, and health-related quality of life (HRQoL). ResultsIn the intention-to-treat analysis, the HOMA-IR index decreased significantly in all active groups compared to placebo (metformin −2.4, 95 % CI −4.1 to −0.8, p = 0.004; testosterone −2.7, 95 % CI −4.3 to −1.1, p = 0.001; combination −3.4, 95 % CI −5.0 to −1.8, p < 0.001). Combination therapy was not superior to testosterone alone in decreasing insulin resistance (−0.7, 95 % CI −2.3 to 0.9, p = 0.383). Only the combination of metformin plus testosterone significantly increased total and free testosterone concentrations, compared to placebo. No significant changes in body composition (except for a higher decrease in fat mass in the metformin and combination group), metabolic variables, erectile function, or HRQoL were found with any treatment. ConclusionsAmong men with obesity and low testosterone concentrations, the combination of metformin plus testosterone, metformin only, and testosterone only, compared to placebo, reduced insulin resistance with no evidence of additive benefit.

One Bout of Resistance Training Does Not Enhance Metformin Actions in Prediabetic and Diabetic Individuals.

This study aimed to determine the separated and combined effects of metformin and resistance exercise on glycemic control, insulin sensitivity, and insulin-like growth factor 1 (IGF-1) in overweight/obese individuals with prediabetes and type 2 diabetes mellitus. Fourteen adults with a body mass index of 32.1 ± 4.1 kg·m-2, insulin resistance (HOMA-2 1.6 ± 0.6), and poor glycemic control (glycated hemoglobin, 6.9% ± 0.9%; 51.9 ± 10.7 mmol·mol-1) while taking metformin (1561 ± 470 g·d-1) were recruited. Participants underwent four 72-h long experimental trials in a randomized counterbalanced order, either 1) taking metformin (MET), 2) replacing metformin by placebo pills (PLAC), 3) taking placebo and undergoing a resistance training bout (RT + PLAC), and 4) taking metformin and undergoing the same RT bout (RT + MET). Interstitial fluid glucose concentration was frequently sampled to obtain 72-h glucose area under the curve (GAUC) and the percentage hyperglycemic glucose readings (>180 mg·dL-1; GPEAKS). Insulin sensitivity (i.e., HOMA-2) and IGF-1 were also assessed. HOMA-2 was not affected by treatments. GAUC and GPEAKS were similarly reduced below PLAC during RT + MET and MET (all P < 0.05). In contrast, RT + PLAC did not affect glucose concentration. Metformin decreased serum IGF-1 concentrations (P = 0.006), and RT did not reverse this reduction. A bout of full-body RT does not interfere or aid on metformin's blood glucose-lowering actions in individuals with prediabetes and type 2 diabetes mellitus.

Metformin in Combination with Progesterone Improves the Pregnancy Rate for Patients with Early Endometrial Cancer.

Objective. To study the therapeutic effects of metformin in combination with medroxyprogesterone in the early endometrial cancer patients with fertility requirements. A total of 120 patients with early endometrial cancer admitted to and treated in our hospital were enrolled and evenly assigned into two groups according to different therapeutic regimens, namely, metformin group (metformin combined with medroxyprogesterone acetate) and control group (medroxyprogesterone acetate alone). The objective response rate (ORR) and disease control rate (DCR) were 71.7% (43/60) and 90.0% (54/60) in the metformin group and 53.3% (32/60) and 78.3% (47/60) in the control group, respectively. Adverse reactions such as gastrointestinal reaction, headache, and insomnia were mainly observed in patients. The body mass index (BMI) declined from (34.43 ± 4.34) kg/m2 to (24.77 ± 2.39) kg/m2 in the metformin group and from (33.37 ± 4.49) kg/m2 to (31.28 ± 3.55) kg/m2 in the control group after treatment. After treatment, serum levels of vascular endothelial growth factor (VEGF), angiotensin-2 (Ang-2), carbohydrate antigen 125 (CA125), and CA19-9 in the metformin group were significantly lower than those in the control group (P = 0.005, P < 0.001, P = 0.002, and P < 0.001). During follow-up, the pregnancy rate was 81.7% (49/60) in the metformin group and 61.7% (37/60) in the control group, and the former was prominently higher than the latter (P = 0.025). Metformin in combination with progesterone is effective in treating early endometrial cancer patients with fertility requirements, which significantly reduced the BMI of patients and increased the pregnancy rate after treatment.

Effects of 18-months metformin versus placebo in combination with three insulin regimens on RNA and DNA oxidation in individuals with type 2 diabetes: A post-hoc analysis of a randomized clinical trial

Formation of reactive oxygen species has been linked to the development of diabetes complications. Treatment with metformin has been associated with a lower risk of developing diabetes complications, including when used in combination with insulin. Metformin inhibits Complex 1 in isolated mitochondria and thereby decreases the formation of reactive oxygen species. Thus, we post-hoc investigated the effect of metformin in combination with different insulin regimens on RNA and DNA oxidation in individuals with type 2 diabetes. Four hundred and fifteen individuals with type 2 diabetes were randomized (1:1) to blinded treatment with metformin (1,000 mg twice daily) versus placebo and to (1:1:1) open-label biphasic insulin, basal-bolus insulin, or basal insulin therapy in a 2 × 3 factorial design. RNA and DNA oxidation were determined at baseline and after 18 months measured as urinary excretions of 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG), respectively. Urinary excretion of 8-oxoGuo changed by +7.1% (95% CI: 0.5% to 14.0%, P = 0.03) following metformin versus placebo, whereas changes in 8-oxodG were comparable between intervention groups. Biphasic insulin decreased urinary excretion of 8-oxoGuo (within-group: −9.6% (95% CI: −14.4% to −4.4%)) more than basal-bolus insulin (within-group: 5.2% (95% CI: −0.5% to 11.2%)), P = 0.0002 between groups, and basal insulin (within-group: 3.7% (95% CI: −2.0% to 9.7%)), P = 0.0007 between groups. Urinary excretion of 8-oxodG decreased more in the biphasic insulin group (within-group: −9.9% (95% CI: −14.4% to −5.2%)) than basal-bolus insulin (within group effect: −1.2% (95% CI: −6.1% to 3.9%)), P = 0.01 between groups, whereas no difference was observed compared with basal insulin. In conclusion, eighteen months of metformin treatment in addition to different insulin regimens increased RNA oxidation, but not DNA oxidation. Biphasic insulin decreased both RNA and DNA oxidation compared with other insulin regimens.

Metformin in combination with genistein ameliorates skeletal muscle inflammation in high-fat diet fed c57BL/6 mice

Although the beneficial effects of metformin (MET) and genistein in ameliorating inflammation have been elucidated, their combined impacts on skeletal muscle inflammation have not been clearly understood. This study aimed to examine the possible preventive effect of MET in combination with genistein on skeletal muscle inflammation in high-fat diet (HFD) fed C57BL/6 mice. Fifty C57BL/6 male mice were fed on an HFD for 10 weeks. The mice were categorized into five groups, control, HFD, HFD + MET (0.23%), HFD + genistein (0.2%), and HFD + MET + genistein for 12 weeks. The results showed that treatment with MET and genistein, either alone or in combination, led to reduced weight gain, fasting blood glucose, plasma insulin, HOMA-IR levels, and Area Under the Curves (AUCs) in ipGTT. MET in combination with genistein demonstrated a decreasing effect on macrophages infiltration rate compared to genistein and MET groups alone. The expression of iNOS was reduced, whereas the expression of M2 macrophage markers was increased in combined treatment of MET and genistein. Furthermore, MET in combination with genistein reduced the expression of TNF-α, IL-1β, MCP-1, and IL-6 and increased the expression of IL-10 in comparison with genistein and MET groups alone. Plasma and skeletal muscle triglycerides and intra-myocellular lipid deposition were reversed by treatment with MET and genistein, alone or in combination. These results imply that the combination therapy of MET and genistein may have therapeutic potential for decreasing obesity-induced skeletal muscle inflammation in the HFD-fed model.

Abstract 1775: Metformin-mediated natural killer cell cytotoxicity in head and neck squamous cell carcinoma

Abstract Head and Neck Squamous Cell Carcinoma (HNSCC) is the 6th most common cancer worldwide. Even with intensive treatment, up to 50% of patients will relapse. Checkpoint inhibitors, including antibodies targeting programmed death 1 (PD-1), have dramatically improved survival outcomes but only elicit a response in 20% of patients. PD-1 is expressed on both T-cells and Natural Killer (NK) cells, and depletion of NK cells has been linked to poor prognosis in several solid tumors. NK cells are essential to the innate immune response, do not require MHC-1 expression for recognition, and can stimulate an anti-cancer response through release of cytotoxic granules and direct killing of cancer cells. Upregulation of several interleukins including IL-6, which induces the JAK/STAT3 pathway and subsequently inhibits cancer cell apoptosis, is correlated with a poor prognosis in HNSCC patients. Importantly, inhibition of phosphorylated STAT3 (pSTAT3) increases NK-specific cancer cytotoxicity, NK cell cytokine release, and anti-tumor cell chemokines. Therefore, we hypothesize that impaired NK cell cytotoxicity results in a poor response to immunotherapy. We have shown that a common anti-diabetes drug with anti-cancer properties, metformin, downregulates NK pSTAT3 with subsequent increase in cytotoxicity of peripheral NK cells in HNSCC patients. Metformin also decreases pSTAT3 pathway related cytokine release from HNSCC cell lines. However, it remains unclear whether metformin-mediated enhanced NK cytotoxicity was through a direct effect on NK cells or indirect through inhibition of pSTAT3 in tumor cells and subsequent decrease in inhibitory cytokine release. In addition, inhibiting pSTAT3 could lead to further activation of innate immunity through activation of NK cell cytotoxicity complementing current PD-1 inhibitor therapy and improved treatment response. Here we report the contribution of metformin-mediated direct and indirect effects on NK cell cytotoxic functions and the combined effect of metformin and pembrolizumab using patient samples from a clinical trial and ex vivo models. Understanding metformin-mediated regulation of pSTAT3 and downstream pathways will provide necessary insight to potentially overcome resistance to PD-1 inhibitors and identifying novel treatment combinations for this disease. Citation Format: McKenzie Crist, Maria Lehn, Trisha Wise-Draper. Metformin-mediated natural killer cell cytotoxicity in head and neck squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1775.

Effects of Metformin in Combination with a Herbal Capsule (Glucoblock) on Insulin Resistance and Oxidative Stress Index in Type 2 Diabetic Rats

Aim: This study evaluated the effects of metformin in combination with a herbal capsule (glucoblock) on insulin resistance and oxidative stress index in type 2 diabetic rats.&#x0D; Methodology: A total of 35 male Wistar albino rats weighing between 120-220 g were used for this study. The rats were placed on high fat diet, and diabetes was induced by a single intraperitoneal injection of freshly prepared streptozotocin (STZ) (45 mg/kg body wt). Fasting plasma glucose (FPG) was determined using the glucose oxidase method. Fasting plasma insulin (FPI), total oxidant status (TOS), total antioxidant status (TAS) and superoxide dismutase (SOD) levels were quantitatively determined by a rat-specific sandwich-enzyme linked immunosorbent assay (ELISA) method. Insulin resistance (IR) was determined using the homeostatic model assessment for insulin resistance (HOMA-IR) method. Oxidative stress index (OSI) was determined by the ratio of TOS to TAS. Phytochemical analysis on the herbal capsule was done using classical methods.&#x0D; Results: The results revealed the presence of alkaloids (100.31μg/mg), flavonoids (131.45μg/mg), cardiac glycosides (55.93μg/mg) and saponins (61.47μg/mg) in the herbal drug glucoblock. The results showed significantly lower FPG levels in the treatment groups when compared to the diabetic control. Group 3 administered metformin had significantly higher FPG levels compared to the negative control. Group 4 administered the herbal drug glucoblock and group 5 administered a combination of metformin and glucoblock, showed no significant differences in FPG levels when compared to the negative control. The diabetic control had significantly higher FPI levels compared to the negative control and treatment groups. The treatment groups showed no significant differences in FPI levels when compared to the negative control. HOMA-IR was significantly higher in the diabetic control compared to the negative control and treatment groups. Also, HOMA-IR values in the treatment groups showed no significant difference compared to the negative control except for group 3 (metformin), that was significantly higher than the negative control. SOD was significantly lower in the diabetic control, compared to the negative control and treatment groups. There were no significant differences in SOD levels in the treatment groups compared to the negative control. TOS levels in the negative control group and treatment groups were significantly lower, compared to the diabetic control. TAS was significantly lower in the diabetic control and treatment groups compared to the negative control. OSI in the diabetic control was significantly higher, compared to the negative control and treatment groups. Also, the treatment groups had significantly higher OSI compared to the negative control.&#x0D; Conclusion: High fat diet and streptozotocin induction produced significant insulin resistance and oxidative stress in the diabetic rats. Glucoblock was more effective in reducing insulin resistance compared to metformin. The combination showed synergistic drug-herb reaction as glucoblock potentiated the actions of metformin. Both showed antioxidant potential but were not effective in lowering oxidative stress to normal levels. There is need to incorporate antioxidant therapy in the treatment protocol for diabetes mellitus.

Antitumor Effect of Metformin in Combination with Binimetinib on Melanoma Cells.

Cutaneous melanoma is a fatal disease for patients with distant metastasis. Metformin is the most widely used anti-diabetic drug, and proved to suppress cell proliferation and metastasis in diverse cancers including melanoma. We previously reported that MEK inhibitor trametinib increases the expression of epithelial-mesenchymal transition (EMT) regulators and melanoma cell motility, which are suppressed by addition of metformin in A375 melanoma cells. To confirm our findings further, we first evaluated the effect of metformin in combination with another MEK inhibitor binimetinib on cell viability in G361 melanoma cells. We then investigated whether binimetinib affects the expression of EMT regulators and cell motility. We finally monitored the effect of metformin on binimetinib-induced cell migration. Cell viability assay showed that combination index (CI) value at ED50 is 0.80, suggesting synergy for the combination of metformin with binimetinib. Our results also revealed that binimetinib increased the expression of EMT regulators such as integrin αV, fibronectin and slug, which correlate well with the enhanced cell migration in wound healing assay. Metformin, on the contrary, suppressed the expression of sparc, integrin αV, fibronectin and N-cadherin with the reduced cell motility. The combination treatment showed that metformin counteracts the binimetinib-induced increase of cell motility. Overall, these results suggest that metformin with binimetinib might be useful as a potential therapeutic adjuvant against cell survival and metastatic activity in melanoma patients.

Synergistic Effects of Metformin-Lapatinib Combination on the Expression of Bax in SK-BR3 Cells

Background: HER2-positive breast cancers tend to be more aggressive and are associated with poorer outcomes than other types of breast cancer. Metformin, the first-line medication for the treatment of type 2 diabetes, has anticancer activity against various cancerous cells. Objectives: We assessed the cytotoxic effect of metformin in combination with Lapatinib on the SK-BR3 cells. Methods: Following culturing cells, IC50 of metformin and lapatinib were calculated using MTT assay after 48h of treatment with different concentrations of metformin and lapatinib alone and in combination. The level of pro-apoptotic protein Bax expression was measured by western blot analysis. Results: Metformin and lapatinib could significantly inhibit the cell viability of SKBR-3 in a dose-dependent manner, and the minimum cytotoxic effect of these drugs was observed after 48 h at 5 mM and 50 nM, respectively. Several combinations of metformin with lapatinib showed a synergistic efficacy on the cell viability inhibition, which could decrease the IC50 of lapatinib from 500 nM to at least 200 nM. The strongest synergistic cytotoxic effect on the cell viability was observed at 40 mM of metformin plus 400 nM of lapatinib. Furthermore, after 48h of co-treatment with metformin-lapatinib combination, the level of pro-apoptotic Bax expression was significantly increased at 10 mM of metformin plus 200 nM of lapatinib. Conclusions: This study demonstrated that the metformin-lapatinib combination may be a valuable candidate for breast cancer patients with HER2 overexpression. However, further studies are needed to make a definitive conclusion.

Metformin may adversely affect orthostatic blood pressure recovery in patients with type 2 diabetes: substudy from the placebo-controlled Copenhagen Insulin and Metformin Therapy (CIMT) trial

BackgroundMetformin has been shown to have both neuroprotective and neurodegenerative effects. The aim of this study was to investigate the effect of metformin in combination with insulin on cardiovascular autonomic neuropathy (CAN) and distal peripheral neuropathy (DPN) in individuals with type 2 diabetes (T2DM).MethodsThe study is a sub-study of the CIMT trial, a randomized placebo-controlled trial with a 2 × 3 factorial design, where 412 patients with T2DM were randomized to 18 months of metformin or placebo in addition to open-labelled insulin. Outcomes were measures of CAN: Changes in heart rate response to deep breathing (beat-to-beat), orthostatic blood pressure (OBP) and heart rate and vibration detection threshold (VDT) as a marker DPN. Serum levels of vitamin B12 and methyl malonic acid (MMA) were analysed.ResultsAfter 18 months early drop in OBP (30 s after standing) was increased in the metformin group compared to placebo: systolic blood pressure drop increased by 3.4 mmHg (95% CI 0.6; 6.2, p = 0.02) and diastolic blood pressure drop increased by 1.3 mmHg (95% CI 0.3; 2.6, p = 0.045) compared to placebo. Beat-to-beat variation decreased in the metformin group by 1.1 beats per minute (95% CI − 2.4; 0.2, p = 0.10). Metformin treatment did not affect VDT group difference − 0.33 V (95% CI − 1.99; 1.33, p = 0.39) or other outcomes. Changes in B12, MMA and HbA1c did not confound the associations.ConclusionsEighteen months of metformin treatment in combination with insulin compared with insulin alone increased early drop in OBP indicating an adverse effect of metformin on CAN independent of vitamin B12, MMA HbA1c.Trial registration The protocol was approved by the Regional Committee on Biomedical Research Ethics (H–D-2007-112), the Danish Medicines Agency and registered with ClinicalTrials.gov (NCT00657943).

Exercise improves metformin 72-h glucose control by reducing the frequency of hyperglycemic peaks.

To determine the separated and combined effects of metformin and exercise on insulin sensitivity and free-living glycemic control in overweight individuals with prediabetes/type 2 diabetes (T2DM). We recruited 16 adults with BMI of 32.7 ± 4.3kgm-2 and insulin resistance (HOMA-IR 3.2 ± 0.4) under chronic metformin treatment (1234 ± 465gday-1) enrolled in a high-intensity interval training (HIIT) program. Participants underwent four 72-h experimental trials in a random-counterbalanced order: (1) maintaining their habitual metformin treatment (MET); (2) replacing metformin treatment by placebo (CON); (3) placebo plus two HIIT sessions (EX + CON), and (4) metformin plus two HIIT sessions (MET + EX). We used intermittently scanned continuous glucose monitoring (isCGM) during 72h in every trial to obtain interstitial fluid glucose area under the curve (IFGAUC) and the percentage of measurements over 180mgdL-1 (% IFGPEAKS). Insulin sensitivity was assessed on the last day of each trial with HOMA-IR index and calculated insulin sensitivity (CSI) from intravenous glucose tolerance test. IFGAUC was lower in MET + EX and MET than in CON (P = 0.011 and P = 0.025, respectively). In addition, IFGAUC was lower in MET + EX than in EX + CON (P = 0.044). %IFGPEAKS were only lower in MET + EX in relation to CON (P = 0.028). HOMA-IR and CSI were higher in CON in comparison with MET + EX (P = 0.011 and P = 0.022, respectively) and MET (P = 0.006 and P < 0.001, respectively). IFGAUC showed a significant correlation with HOMA-IR. Intense aerobic exercise in patients with diabetes and prediabetes under metformin treatment reduces free-living 72-h blood hyperglycemic peaks. This may help to prevent the development of cardiovascular complications associated with diabetes.