Effect of Metformin vs Placebo on Invasive Disease-Free Survival in Patients With Breast Cancer: The MA.32 Randomized Clinical Trial

Neratinib and metformin: A novel therapeutic approach against HER2-Positive Breast Cancer

BACKGROUND

HER2-positive breast cancer (BC) is highly aggressive with a poor prognosis. It is driven by HER2 oncoprotein activation/crosstalk with other receptors like EGFR/(HER1), HER3, and HER4, in addition to IGF-1R, making these receptors ideal therapeutic targets as they are expressed/overexpressed in this subtype. We postulated that targeting HER2 and IGF-1R together is a promising therapy for HER2-positive BC. Thus, we explored the outcome of a novel combination treatment using neratinib, a pan-HER inhibitor, and metformin, an IGF-1R inhibitor, on HER2-positive BC cells.

METHODS

In this investigation, we used cellular and molecular biology techniques in addition to an angiogenesis model and tissue microarray analysis.

RESULTS

Our data revealed that this combination therapy significantly reduced cell viability compared to individual treatments and exhibited a synergistic effect in HER2-positive BC cells. Moreover, the combination disrupted cell cycle progression and inhibited colony formation, and invasion of HER2-positive BC cells; this is accompanied by the deregulation of HER1-3 and IGF-1R expression patterns, in addition to Caspase-3, BCL2, Fascin, and Vimentin. Moreover, key regulator molecular pathways, including, ERK1/2, AKT, p38 MAPK, and mTOR, were significantly downregulated upon treatment with neratinib and metformin combination. Additionally, our data pointed out that neratinib and metformin combination inhibited angiogenesis, in-ovo, an important biological event in cancer progression. Finally, using a cohort of 55 HER2-positive BC samples, we revealed that HER2 and IGF-1R are co-expressed in most of the cases.

CONCLUSIONS

These findings suggest that neratinib and metformin combination can present a promising strategy for targeting multiple pathways in HER2-positive BC.

G-protein coupled receptors in metabolic reprogramming and cancer

G-protein coupled receptors (GPCR) are one of the frequently investigated drug targets. GPCRs are involved in many human pathophysiologies that lead to various disease conditions, such as cancer, diabetes, and obesity. GPCR receptor activates multiple signaling pathways depending on the ligand and tissue type. However, this review will be limited to the GPCR-mediated metabolic modulations and the activation of relevant signaling pathways in cancer therapy. Cancer cells often have reprogrammed cell metabolism to support tumor growth and metastatic plasticity. Many aggressive cancer cells maintain a hybrid metabolic status, using both glycolysis and mitochondrial metabolism for better metabolic plasticity. In addition to glucose and glutamine pathways, fatty acid is a key mitochondrial energy source in some cancer subtypes. Recently, targeting alternative energy pathways like fatty acid beta-oxidation (FAO) has attracted great interest in cancer therapy. Several in vitro and in vivo experiments in different cancer models reported encouraging responses to FAO inhibitors. However, due to the potential liver toxicity of FAO inhibitors in clinical trials, new approaches to indirectly target metabolic reprogramming are necessary for in vivo targeting of cancer cells. This review specifically focused on free fatty acid receptors (FFAR) and β-adrenergic receptors (β-AR) because of their reported significance in mitochondrial metabolism and cancer. Further understanding the pharmacology of GPCRs and their role in cancer metabolism will help repurpose GPCR-targeting drugs for cancer therapy and develop novel drug discovery strategies to combine them with standard cancer therapy to increase anticancer potential and overcome drug resistance.

Obesity-specific improvement of lung cancer outcomes and immunotherapy efficacy with metformin

BACKGROUND

Preclinical cancer studies ascribe promising anticancer properties to metformin. Yet, clinical findings vary, casting uncertainty on its therapeutic value for non-small cell lung cancer (NSCLC) patients. We hypothesized that metformin could benefit obese and overweight patients with NSCLC.

METHODS

We retrospectively analyzed 2 clinical cohorts and employed complementary mouse models to test our hypothesis. One cohort included NSCLC patients with overweight body mass index (≥25 kg/m2, n = 511) and nonoverweight body mass index (<25 kg/m2, n = 232) who underwent lobectomy, evaluating metformin's impact on clinical outcomes. Another cohort examined metformin's effect on progression-free survival after immune checkpoint inhibitors in overweight (n = 284) vs nonoverweight (n = 184) NSCLC patients. Metformin's effects on tumor progression, antitumor immunity, and immune checkpoint inhibitor response in obese and normal-weight mice were assessed with lung cancer models.

RESULTS

Metformin is associated with increased recurrence-free survival in overweight patients (hazard ratio [HR] = 0.47, 95% confidence interval [CI] = 0.24 to 0.94; P = .035) after lobectomy. It also corrected accelerated tumor growth in diet-induced obese mouse models in a lymphocyte-specific manner while reversing several mechanisms of immune suppression potentiated by obesity. Programmed cell death 1 blockade coupled with metformin was more effective at limiting tumor burden in obese mice and correlated with progression-free survival only in overweight patients on immunotherapy (HR = 0.60, 95% CI = 0.39 to 0.93; P = .024).

CONCLUSIONS

Metformin may improve lung cancer-specific clinical outcomes in obese and overweight lung cancer patients and enhance immunotherapy efficacy in this growing population. This work identifies obesity as a potential predictive biomarker of metformin's anticancer and immunotherapy-enhancing properties in lung cancer while shedding light on the underlying immunological phenomena.

A randomized phase II/III study of paclitaxel/carboplatin/metformin versus paclitaxel/carboplatin/placebo as initial therapy for measurable stage III or IVA, stage IVB, or recurrent endometrial cancer: An NRG oncology/GOG study

INTRODUCTION

We evaluated the efficacy of the addition of the anti-diabetic drug metformin to standard-of-care paclitaxel and carboplatin (PC) in patients with advanced and recurrent endometrial cancer (EC).

METHODS

In this phase II/III trial, EC patients with chemotherapy-naïve stage III/IVA (with measurable disease) and stage IVB or recurrent (with or without measurable disease) disease were randomly assigned to PC/metformin (850 mg BID) versus PC/placebo. Metformin or placebo was continued as maintenance therapy after completion of PC until disease progression. The primary endpoint of phase II was progression-free survival (PFS). The primary endpoint of phase III was overall survival (OS). Secondary endpoints were objective response, duration of response, and toxicity.

RESULTS

From 3/17/2014 to 12/22/2017, 448 patients were randomized to phase II/III studies, and the data were frozen for interim analysis. The phase II study deemed metformin worthy of further investigation in the phase III study. The interim phase III analysis stopped accrual for futility on 2/1/2018. The addition of metformin to PC had a slightly higher hazard of death compared to the PC regimen (HR = 1.088; 90% CI 0.803 to 1.475), which was sufficient to close the study early. The PFS had (HR = 0.814; 90% CI 0.635 to 1.043). At a median follow-up of 10 months and 121 deaths, median OS was not determined and 28 months, on PC/placebo and PC/metformin, respectively.

CONCLUSION

The hazard ratios for PFS and OS endpoints was not sufficiently decreased with the addition of metformin to PC to justify continuing the trial.

Targeting PI3K inhibitor resistance in breast cancer with metabolic drugs

Activating PIK3CA mutations, present in up to 40% of hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (Her2-) breast cancer (BC) patients, can be effectively targeted with the alpha isoform-specific PI3K inhibitor Alpelisib. This treatment significantly improves outcomes for HR+, Her2-, and PIK3CA-mutated metastatic BC patients. However, acquired resistance, often due to aberrant activation of the mTOR complex 1 (mTORC1) pathway, remains a significant clinical challenge. Our study, using in vitro and orthotopic xenograft mouse models, demonstrates that constitutively active mTORC1 signaling renders PI3K inhibitor-resistant BC exquisitely sensitive to various drugs targeting cancer metabolism. Mechanistically, mTORC1 suppresses the induction of autophagy during metabolic perturbation, leading to energy stress, a critical depletion of aspartate, and ultimately cell death. Supporting this mechanism, BC cells with CRISPR/Cas9-engineered knockouts of canonical autophagy genes showed similar vulnerability to metabolically active drugs. In BC patients, high mTORC1 activity, indicated by 4E-BP1T37/46 phosphorylation, correlated with p62 accumulation, a sign of impaired autophagy. Together, these markers predicted poor overall survival in multiple BC subgroups. Our findings reveal that aberrant mTORC1 signaling, a common cause of PI3K inhibitor resistance in BC, creates a druggable metabolic vulnerability by suppressing autophagy. Additionally, the combination of 4E-BP1T37/46 phosphorylation and p62 accumulation serves as a biomarker for poor overall survival, suggesting their potential utility in identifying BC patients who may benefit from metabolic therapies.

Metformin's anticancer odyssey: Revealing multifaceted mechanisms across diverse neoplastic terrains- a critical review

Metformin, initially prescribed as an oral hypoglycemic medication for type 2 diabetes, has recently gained attention for its potential anticancer effects. Its history dates to 1918, when guanidine, a component of the traditional European herb Galega officinalis, was found to reduce glycemia. This review precisely examines the mechanisms underlying Metformin's anticancer effects across various neoplastic conditions. This investigation explores the complex interactions between metformin and major signaling pathways associated with carcinogenesis, including AMP-activated protein kinase (AMPK), mTOR, and insulin-like growth factor (IGF) pathways. The review emphasizes Metformin's diverse effects on angiogenesis, inflammation, apoptosis, and cellular metabolism in cancer cells. Additionally, new data on metformin's capacity to alter the tumor microenvironment and enhance immune surveillance systems against cancer are examined. The review underscores Metformin's potential for repurposing in oncology, emphasizing its clinical relevance as an adjuvant therapy for various cancers. The review provides insightful information about the complex anticancer mechanisms of metformin by combining data from preclinical and clinical studies. These findings not only broaden our knowledge of the effects of metformin but also open new avenues for oncology research and treatment developments.

Melanophilin inhibit the growth and lymph node metastasis of triple negative breast cancer via the NONO-SPHK1-S1P axis

BACKGROUND

Triple negative breast cancer (TNBC) is the most aggressive breast cancer subtype with the worst prognosis, and there are no targeted treatments available. TNBC patients are more likely to develop metastases and relapse than patients with other breast cancer subtypes. Lymph node metastasis is the first sign of metastatic spread. We aimed to characterize the mechanism of lymph node metastasis in TNBC to provide a new strategy for the treatment of TNBC.

METHODS

Gene Expression Omnibus (GEO) TNBC database was utilized to screen for genes related to N staging. Screening the downstream target of Melanophilin (MLPH) in TNBC through RNA sequencing (RNA seq) analysis. Protein mass spectrometry was utilized to analyze the protein which interacts with MLPH, and RNA binding protein immunoprecipitation and quantitative real-time PCR (RIP qPCR) were utilized to verify the regulation of sphingosine kinase 1 (SPHK1) expression by MLPH through Non-POU domain-containing octamer-binding protein (NONO). Cell functional assays and in vivo models experiments further confirmed the effects of MLPH on proliferation and lymph node metastasis of TNBC through the SPHK1-S1P axis.

RESULTS

MLPH is downregulated in TNBC and inhibits tumor growth and lymph node metastasis though the MLPH-NONO-SPHK1-S1P pathway. NONO was identified as an essential factor involved in SPHK1 mRNA splicing. MLPH interacts with NONO to inhibit SPHK1 mRNA splicing of SPHK1, which reduces the content of S1P, thereby inhibiting growth and lymph node metastasis in TNBC.

CONCLUSIONS

This study preliminarily elucidated a mechanism underlying lymph node metastasis in TNBC and identified the role of the MLPH-NONO-SPHK1-S1P axis in regulating proliferation and lymph node metastasis in TNBC. These findings may help design strategies for predicting and treating metastasis in TNBC.

Pharmacological Dissection Identifies Retatrutide Overcomes the Therapeutic Barrier of Obese TNBC Treatments through Suppressing the Interplay between Glycosylation and Ubiquitylation of YAP

Triple-negative breast cancer (TNBC) in obese patients remains challenging. Recent studies have linked obesity to an increased risk of TNBC and malignancies. Through multiomic analysis and experimental validation, a dysfunctional Eukaryotic Translation Initiation Factor 3 Subunit H (EIF3H)/Yes-associated protein (YAP) proteolytic axis is identified as a pivotal junction mediating the interplay between cancer-associated adipocytes and the response to anti-cancer drugs in TNBC. Mechanistically, cancer-associated adipocytes drive metabolic reprogramming resulting in an upregulated hexosamine biosynthetic pathway (HBP). This aberrant upregulation of HBP promotes YAP O-GlcNAcylation and the subsequent recruitment of EIF3H deubiquitinase, which stabilizes YAP, thus promoting tumor growth and chemotherapy resistance. It is found that Retatrutide, an anti-obesity agent, inhibits HBP and YAP O-GlcNAcylation leading to increased YAP degradation through the deprivation of EIF3H-mediated deubiquitylation of YAP. In preclinical models of obese TNBC, Retatrutide downregulates HBP, decreases YAP protein levels, and consequently decreases tumor size and enhances chemotherapy efficacy. This effect is particularly pronounced in obese mice bearing TNBC tumors. Overall, these findings reveal a critical interplay between adipocyte-mediated metabolic reprogramming and EIF3H-mediated YAP proteolytic control, offering promising therapeutic strategies to mitigate the adverse effects of obesity on TNBC progression.

Metformin for patients with advanced stage ovarian cancer: A randomized phase II placebo-controlled trial

OBJECTIVE

The primary aim of this study was to determine if metformin, an oral biguanide administered with first-line chemotherapy and continued as maintenance therapy, improves progression-free survival (PFS) for patients with advanced-stage ovarian cancer.

METHODS

Patients with pathologically confirmed advanced-stage ovarian cancer undergoing primary debulking or neoadjuvant platinum-based chemotherapy followed by surgery were eligible to participate. Patients were randomized 1:1 to receive platinum/taxane-based chemotherapy with metformin 850 mg orally twice per day or placebo, followed by maintenance therapy (metformin or placebo) for two years from the date of randomization.

RESULTS

108 evaluable patients were enrolled; 54 were randomly assigned to metformin, and 54 to placebo. Sixty-six percent (n = 71) received neoadjuvant therapy, 31 % (n = 33) primary debulking surgery, and 88 % (n = 93) had tumors of high-grade serous histology. The primary endpoint, PFS, was not significantly different between the treatment groups (1-sided p-value = 0.31; adjusted hazard ratio [HR] = 0.87, 95 % confidence interval [CI]: 0.56-1.36). Median PFS was 15.4 months (95 % CI: 11.2-23,5) for metformin and 14.3 months (95 % CI: 11.6-18.0) for placebo. Overall survival (OS) was not significantly different (2-sided p-value = 0.21; adjusted HR = 1.49, 95 % CI: 0.86-2.59), with a median of 40.7 months (95 % CI: 28.0-48.2) for metformin versus 43.8 months (95 % CI: 35.3-57.2) for placebo. The addition of metformin was well tolerated, and there were no differences in toxicity between the two groups.

CONCLUSION

Although it was well-tolerated, adding metformin to first-line platinum/taxane-based therapy does not improve PFS or OS for patients with newly diagnosed advanced stage ovarian cancer.

Early downmodulation of tumor glycolysis predicts response to fasting-mimicking diet in triple-negative breast cancer patients

In preclinical experiments, cyclic fasting-mimicking diets (FMDs) showed broad anticancer effects in combination with chemotherapy. Among different tumor types, triple-negative breast cancer (TNBC) is exquisitely sensitive to FMD. However, the antitumor activity and efficacy of cyclic FMD in TNBC patients remain unclear. Here, we show that a severely calorie-restricted, triweekly, 5-day FMD regimen results in excellent pathologic complete response (pCR) rates (primary endpoint) and long-term clinical outcomes (secondary endpoints) when combined with preoperative chemotherapy in 30 patients with early-stage TNBC enrolled in the phase 2 trial BREAKFAST. Bulk and single-cell RNA sequencing analysis revealed that highly glycolytic cancer cells, myeloid cells, and pericytes from tumors achieving pCR undergo a significant, early downmodulation of pathways related to glycolysis and pyruvate metabolism. Our findings pave the wave for conducting larger clinical trials to investigate the efficacy of cyclic FMD in early-stage TNBC patients and to validate early changes of intratumor glycolysis as a predictor of clinical benefit from nutrient restriction. This study was registered at Clinicaltrials.gov (NCT04248998).

Carbohydrate kinase inhibition: a promising strategy in cancer treatment

Carbohydrate kinases (CKs) are pivotal in various biological processes, including energy consumption, cell signaling, and biosynthesis. They are a group of enzymes that facilitate the phosphorylation of carbohydrates, playing a crucial role in cellular metabolism. These enzymes facilitate the transfer of a phosphate group from a high-energy donor like ATP to a specified location on a carbohydrate substrate. Dysregulated kinase activity drives tumor growth and progression. Inhibitors targeting these enzymes have been developed and used in cancer therapy. The CK family encompasses three major types: hexokinases, ribokinases, and phosphatidylinositol kinases, with inhibitors of paramount importance in cancer treatment. This review explores the role of CKs in cancer and its inhibitors, providing insights into improving existing inhibitors and designing new ones.

Harnessing the tumor microenvironment: targeted cancer therapies through modulation of epithelial-mesenchymal transition

The tumor microenvironment (TME) is integral to cancer progression, impacting metastasis and treatment response. It consists of diverse cell types, extracellular matrix components, and signaling molecules that interact to promote tumor growth and therapeutic resistance. Elucidating the intricate interactions between cancer cells and the TME is crucial in understanding cancer progression and therapeutic challenges. A critical process induced by TME signaling is the epithelial-mesenchymal transition (EMT), wherein epithelial cells acquire mesenchymal traits, which enhance their motility and invasiveness and promote metastasis and cancer progression. By targeting various components of the TME, novel investigational strategies aim to disrupt the TME's contribution to the EMT, thereby improving treatment efficacy, addressing therapeutic resistance, and offering a nuanced approach to cancer therapy. This review scrutinizes the key players in the TME and the TME's contribution to the EMT, emphasizing avenues to therapeutically disrupt the interactions between the various TME components. Moreover, the article discusses the TME's implications for resistance mechanisms and highlights the current therapeutic strategies toward TME modulation along with potential caveats.

Metabolic Syndrome and Risks of Breast Cancer Outcomes for Luminal, Triple-Negative, and HER2-Overexpressing Subtypes

BACKGROUND

We evaluated the association between metabolic syndrome (MetS; obesity plus two metabolic risk factors) and breast cancer outcomes according to molecular subtype.

METHODS

This population-based prospective cohort consisted of 3,267 women ages 20 to 69 years diagnosed with a first primary invasive breast cancer from 2004 to 2015 in the Seattle-Puget Sound region. Breast cancer was categorized into three subtypes based on estrogen receptor (ER), progesterone receptor, and HER2 expression: luminal (ER+), triple-negative (ER-/progesterone receptor negative/HER2-), and HER2-overexpressing (H2E; ER-/HER2+) subtypes. We used time-varying Cox models to assess the association of prevalent and incident MetS with risks of recurrence, breast cancer-specific mortality (BCSM), and all-cause mortality (ACM).

RESULTS

MetS was associated with a greater risk of recurrence [HR, 3.24; 95% confidence interval (CI), 1.13-9.33] and BCSM (HR, 5.34; 95% CI, 2.32-12.31) only for the H2E subtype and greater risks of ACM for luminal (HR, 1.92; 95% CI, 1.37-2.68), H2E (HR, 5.09; 95% CI, 2.51-10.32), and all cases combined (HR, 1.90; 95% CI, 1.42-2.53). We also observed heterogeneity in recurrence and mortality outcomes across specific components of MetS and molecular subtypes.

CONCLUSIONS

MetS is associated with ACM among women with breast cancer and with BCSM among women with the H2E subtype.

IMPACT

These results highlight the importance of managing comorbidities to decrease the risk for adverse outcomes among breast cancer survivors.

Metformin and the risk of malignant tumors of digestive system: a mendelian randomization study

BACKGROUND

Observational studies suggest that metformin may reduce the risk of malignant tumors of the digestive system (MTDS), but these findings are often confounded by bias and unmeasured variables. Recent meta-analyses have questioned these associations, emphasizing the need for robust causal inference.

METHODS

Mendelian randomization (MR) was used to evaluate the causal relationship between metformin and MTDS. Genetic variants associated with metformin's molecular targets were selected from GTEx, eQTLGen, and UK Biobank and validated using genetic colocalization to ensure instrument validity. GWAS summary statistics for MTDS, encompassing up to 314,193 controls and 6,847 colorectal cancer cases, were obtained from FinnGen and EBI. The primary analysis employed the inverse-variance weighted (IVW) method, supplemented by MR-Egger, weighted median, and weighted mode analyses. Bonferroni correction was applied to adjust for multiple testing across 14 cancer types.

RESULTS

Genetically proxied metformin use was associated with an increased risk of colorectal cancer (OR = 2.38, 95%CI = 1.38-4.09, P = 0.0018) and related subtypes. No causal relationship was found for hepatocellular carcinoma, gastric cancer, pancreatic cancer, or other digestive system cancers. The robustness of these findings was supported by sensitivity analyses, which indicated no significant pleiotropy, and leave-one-out tests.

CONCLUSION

This study provides robust genetic evidence that metformin use increases the risk of colorectal cancer, challenging its role as a preventive agent for digestive cancers. These findings emphasize the need for clinicians to carefully evaluate the risks and benefits of metformin, particularly in populations at higher risk for colorectal cancer. Future research should focus on delineating the mechanisms underlying this association to optimize the use of metformin in clinical practice.

CancerSCEM 2.0: an updated data resource of single-cell expression map across various human cancers

The field of single-cell RNA sequencing (scRNA-seq) has advanced rapidly in the past decade, generating significant amounts of valuable data for researchers to study complex tumor profiles. This data is crucial for gaining innovative insights into cancer biology. CancerSCEM (https://ngdc.cncb.ac.cn/cancerscem) is a public resource that integrates, analyzes and visualizes scRNA-seq data related to cancer, and it provides invaluable support to numerous cancer-related studies. With CancerSCEM 2.0, scRNA-seq data have increased from 208 to 1466 datasets, covering tumor, matching-normal and peripheral blood samples across 127 research projects and 74 cancer types. The new version of this resource enhances transcriptome analysis by adding copy number variation evaluation, transcription factor enrichment, pseudotime trajectory construction, and diverse biological feature scoring. It also introduces a new cancer metabolic map at the single-cell level, providing an intuitive understanding of metabolic regulation across different cancer types. CancerSCEM 2.0 has a more interactive analysis platform, including four modules and 14 analytical functions, allowing researchers to perform cancer scRNA-seq data analyses in various dimensions. These enhancements are expected to expand the usability of CancerSCEM 2.0 to a broader range of cancer research and clinical applications, potentially revolutionizing our understanding of cancer mechanisms and treatments.

Clinical significance of lipid pathway-targeted therapy in breast cancer

Globally, breast cancer represents the most common cancer and the primary cause of death by cancer in women. Lipids are crucial in human physiology, serving as vital energy reserves, structural elements of biological membranes, and essential signaling molecules. The metabolic reprogramming of lipid pathways has emerged as a critical factor in breast cancer progression, drug resistance, and patient prognosis. In this study, we delve into the clinical implications of lipid pathway-targeted therapy in breast cancer. We highlight key enzymes and potential therapeutic targets involved in lipid metabolism reprogramming, and their associations with cancer progression and treatment outcomes. Furthermore, we detail the clinical trials exploring the anticancer and cancer chemopreventive activity of therapies targeting these molecules. However, the clinical efficacy of these therapies remains controversial, highlighting the urgent need for predictive biomarkers to identify patient subpopulations likely to benefit from such treatment. We propose the Selective Lipid Metabolism Therapy Benefit Hypothesis, emphasizing the importance of personalized medicine in optimizing lipid pathway-targeted therapy for breast cancer patients.

Atherosclerosis and the Bidirectional Relationship Between Cancer and Cardiovascular Disease: From Bench to Bedside, Part 2 Management

The first part of this review highlighted the evolving landscape of atherosclerosis, noting emerging cardiometabolic risk factors, the growing impact of exposomes, and social determinants of health. The prominent role of atherosclerosis in the bidirectional relationship between cardiovascular disease and cancer was also discussed. In this second part, we examine the complex interplay between multimorbid cardio-oncologic patients, cardiometabolic risk factors, and the harmful environments that lend a "syndemic" nature to these chronic diseases. We summarize management strategies targeting disordered cardiometabolic factors to mitigate cardiovascular disease and explore molecular mechanisms enabling more tailored therapies. Importantly, we emphasize the early interception of atherosclerosis through multifactorial interventions that detect subclinical signs (via biomarkers and imaging) to treat modifiable risk factors and prevent clinical events. A concerted preventive effort-referred to by some as a "preventome"-is essential to reduce the burden of atherosclerosis-driven chronic diseases, shifting from mere chronic disease management to the proactive promotion of "chronic health".

Metformin-based nanomedicines for reprogramming tumor immune microenvironment

Immunotherapy has transformed current cancer management, and it has achieved significant progress over last decades. However, an immunosuppressive tumor microenvironment (TME) diminishes the effectiveness of immunotherapy by suppressing the activity of immune cells and facilitating tumor immune-evasion. Adenosine monophosphate-activated protein kinase (AMPK), a key modulator of cellular energy metabolism and homeostasis, has gained growing attention in anti-tumor immunity. Metformin is usually considered as a cornerstone in diabetes management, and its role in activating the AMPK pathway has also been extensively explored in cancer therapy although the findings on its role remain inconsistent. Metformin in a nanomedicine formulation has been found to hold potential in reprogramming the immunosuppressive TME through immunometabolic modulation of both tumor and immune cells. This review elaborates the foundation and progress of immunometabolic reprogramming of the TME via metformin-based nanomedicines, offering valuable insights for the next generation of cancer therapy.

Metabolomics-Driven Biomarker Discovery for Breast Cancer Prognosis and Diagnosis

Breast cancer is a cancer with global prevalence and a surge in the number of cases with each passing year. With the advancement in science and technology, significant progress has been achieved in the prevention and treatment of breast cancer to make ends meet. The scientific intradisciplinary subject of "metabolomics" examines every metabolite found in a cell, tissue, system, or organism from different sources of samples. In the case of breast cancer, little is known about the regulatory pathways that could be resolved through metabolic reprogramming. Evidence related to the significant changes taking place during the onset and prognosis of breast cancer can be obtained using metabolomics. Innovative metabolomics approaches identify metabolites that lead to the discovery of biomarkers for breast cancer therapy, diagnosis, and early detection. The use of diverse analytical methods and instruments for metabolomics includes Magnetic Resonance Spectroscopy, LC/MS, UPLC/MS, etc., which, along with their high-throughput analysis, give insights into the metabolites and the molecular pathways involved. For instance, metabolome research has led to the discovery of the glutamate-to-glutamate ratio and aerobic glycolysis as biomarkers in breast cancer. The present review comprehends the updates in metabolomic research and its processes that contribute to breast cancer prognosis and metastasis. The metabolome holds a future, and this review is an attempt to amalgamate the present relevant literature that might yield crucial insights for creating innovative therapeutic strategies aimed at addressing metastatic breast cancer.

Implications of obesity and insulin resistance for the treatment of oestrogen receptor-positive breast cancer

Breast cancer is the most common cancer in women, and incidence rates are rising, it is thought in part, due to increasing levels of obesity. Endocrine therapy (ET) remains the cornerstone of systemic therapy for early and advanced oestrogen receptor-positive (ER + ) breast cancer, but despite treatment advances, it is becoming more evident that obesity and insulin resistance are associated with worse outcomes. Here, we describe the current understanding of the relationship between both obesity and diabetes and the prevalence and outcomes for ER+ breast cancer. We also discuss the mechanisms associated with resistance to ET and the relationship to treatment toxicity.

Survival benefit of metformin use according to cancer diagnosis in diabetic patients with metabolic syndrome

Background

Metabolic syndrome (MetSyn) is a disease cluster causing cardiovascular disease, cancer, and high mortality. Metformin is the most common antidiabetic agent inhibiting the tumorigenesis and insulin resistance of MetSyn. We describe the association between metformin intake and survival of patients with type 2 diabetes mellitus (T2DM) and MetSyn, according to the presence of cancer.

Methods

We analyzed the clinical characteristics and all-cause mortality of patients with T2DM and MetSyn using a 5-year dataset between January 1, 2009 and December 31, 2013 derived from the Korean National Health Insurance Service-National Health Screening Cohort (NHIS-HEALS). Cox proportional hazards regression models were used to investigate metformin effects adjusted for other potential confounding variables.

Results

Among a total of 43,043 patients with both MetSyn and T2DM, 24,725 patients (57.4 %) received metformin regularly. Female sex, high income, regular exercise, and metformin use were good prognostic factors, whereas hypertension, current smoking, cancer, and diabetes medication (except metformin) were poor prognostic factors. After adjustment for possible confounding variables, metformin showed a significant effect on patient survival (hazard ratio [HR], 0.68; 95 % confidence interval [CI], 0.63-0.75; p < 0.001). The effect of metformin was pronounced on the group of patients with liver, lung, colorectal, or prostate cancers (HR, 0.57; CI, 0.46-0.70).

Conclusions

Metformin intake may be related to favorable survival among patients with T2DM and MetSyn. The efficacy might be more remarkable in those with liver, lung, colorectal, and prostate cancers. The potential benefit of metformin in patients with these risk factors should be further investigated.

Targeting the menopause transition with metformin improves breast cancer outcomes, but discontinuation has deleterious effects on metabolic health: Findings from a preclinical model of postmenopausal breast cancer

Background

Women with obesity and/or type-II-diabetes have an increased breast cancer risk, increased metastasis, and poorer prognosis, especially after menopause. In a rat model of high-fat-diet and menopause-induced weight gain, we previously reported that treatment with the anti-diabetic drug metformin for 8-weeks after ovariectomy (OVX; modeling menopause) reduced growth of existing mammary tumors and inhibited new tumor formation. This identified the menopause transition as a potential window-of-opportunity for interventions to decrease obesity-associated breast cancer incidence and disease progression. Here, we extend these findings to determine if limiting metformin to the peak window of OVX-induced weight gain would have similar anti-cancer effects.

Findings

Metformin during the first four weeks following OVX is critical to reducing tumor burden, as rats treated with metformin early (weeks0-4-postOVX) had reduced tumor burden. Conversely, initiating metformin later in the postOVX period (weeks 4-8postOVX) did not reduce cancer burden. Despite improved tumor outcomes, metformin withdrawal after the early postOVX time had detrimental metabolic effects, including weight gain and increased adiposity, insulin, IGF1, and HOMA-IR, which correlate with increased cancer risk.

Conclusions

These data reveal early-postmenopause as a critical window when metformin decreases progression of existing disease and highlights the importance of maintaining treatment to prevent metabolic dysregulation, which could promote secondary tumors/metastasis. These findings also help explain the disconnect between epidemiological studies reporting anticancer benefits of metformin and more recent clinical trials that failed to see similar efficacy, potentially due to issues of timing and/or inclusion of women outside the early postmenopausal window and/or without underlying metabolic dysfunction.

Anti-Diabetic Therapies and Cancer: From Bench to Bedside

Diabetes mellitus (DM) is a significant risk factor for various cancers, with the impact of anti-diabetic therapies on cancer progression differing across malignancies. Among these therapies, metformin has gained attention for its potential anti-cancer effects, primarily through modulation of the AMP-activated protein kinase/mammalian target of rapamycin (AMPK/mTOR) pathway and the induction of autophagy. Beyond metformin, other conventional anti-diabetic treatments, such as insulin, sulfonylureas (SUs), pioglitazone, and dipeptidyl peptidase-4 (DPP-4) inhibitors, have also been examined for their roles in cancer biology, though findings are often inconclusive. More recently, novel medications, like glucagon-like peptide-1 (GLP-1) receptor agonists, dual GLP-1/glucose-dependent insulinotropic polypeptide (GIP) agonists, and sodium-glucose co-transporter-2 (SGLT-2) inhibitors, have revolutionized DM management by not only improving glycemic control but also delivering substantial cardiovascular and renal benefits. Given their diverse metabolic effects, including anti-obesogenic properties, these novel agents are now under meticulous investigation for their potential influence on tumorigenesis and cancer advancement. This review aims to offer a comprehensive exploration of the evolving landscape of glucose-lowering treatments and their implications in cancer biology. It critically evaluates experimental evidence surrounding the molecular mechanisms by which these medications may modulate oncogenic signaling pathways and reshape the tumor microenvironment (TME). Furthermore, it assesses translational research and clinical trials to gauge the practical relevance of these findings in real-world settings. Finally, it explores the potential of anti-diabetic medications as adjuncts in cancer treatment, particularly in enhancing the efficacy of chemotherapy, minimizing toxicity, and addressing resistance within the framework of immunotherapy.

Progress in antitumor mechanisms and applications of phenformin (Review)

Phenformin, a biguanide compound, has attracted increased attention due to its prominent antitumor activity. As a multi‑target agent, the antitumor effects of phenformin involve a wide range of factors, including inhibition of mitochondrial complex I, activation of AMP‑activated protein kinase, impact on the tumor microenvironment, suppression of cancer stem cells and others. In addition, phenformin has been shown to markedly augment the effectiveness of various clinical treatment methods, including radiotherapy, chemotherapy, targeted therapy and immunotherapy. It is noteworthy that breakthrough progress has been made in the treatment of cancer with phenformin with application in clinical trials for the treatment of melanoma. Phenformin not only reduces the lesion area of patients, but also enhances the efficacy of dalafinib/trimetinib. In the present review, the novel breakthroughs in the antitumor effects and mechanisms of phenformin were discussed. In addition, the current review focuses on the clinical development value of phenformin, striving to provide new insights into the future research direction of phenformin in the field of tumor treatment.

Pancreatic cancer tumor organoids exhibit subtype-specific differences in metabolic profiles

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease characterized by complex metabolic rewiring that enables growth in changing nutrient availability and oxygen conditions. Transcriptome-based prognostic PDAC tumor subtypes, known as 'basal-like' and 'classical' subtypes are associated with differences in metabolic gene expression including genes involved in glycolysis. Tumor subtype-specific metabolism phenotypes may provide new targets for treatment development in PDAC, but their functional relevance has not been fully elucidated. We aimed to investigate differences in metabolic profiles and transcriptomes in tumor models derived from patients with basal-like and classical tumors.

METHODS

Patient-derived organoids (PDOs) were established from tumor biopsies collected from patients with metastatic PDAC, including three PDOs from basal-like and five PDOs from classical tumors. Metabolic analyses included assessment of differences in metabolic activity using Seahorse Glycolysis and Mito Stress tests and 13C-glucose metabolites tracing analysis. In order to investigate the influence of mitochondrial pyruvate transport on metabolic differences, PDOs were treated with the mitochondrial pyruvate carrier 1 (MPC1) inhibitor UK-5099. Prognostic relevance of MPC1 was determined using a tumor tissue microarray (TMA) in resectable, and proteomics profiling in metastatic PDAC datasets. Whole genome and transcriptome sequencing, differential gene expression and gene set enrichment analyses were performed in PDOs.

RESULTS

Metastatic PDAC PDOs showed subtype-specific differences in glycolysis and oxidative phosphorylation (OXPHOS). Basal-like tumor-derived PDOs had a lower baseline extracellular acidification rate, but higher glycolytic reserves and oxygen consumption rate (OCR) than classical tumor-derived PDOs. OCR difference was eliminated following treatment with UK-5099. In the 13C-glucose metabolites tracing experiment, a basal-like tumor PDO showed lower fractions of some M + 2 metabolites but higher sensitivity to UK-5099 mediated reduction in M + 2 metabolites than a classical tumor PDO. Protein level analyses revealed lower MPC1 protein levels in basal-like PDAC cases and association of low MPC1 levels with clinicopathologic parameters of tumor aggressiveness in PDAC. PDO differential gene expression analyses identified additional subtype-specific cellular pathways and potential disease outcome biomarkers.

CONCLUSIONS

Our findings point to distinct metabolic profiles in PDAC subtypes with basal-like tumor PDOs showing higher OXPHOS and sensitivity to MPC1 inhibition. Subtypes-specific metabolic vulnerabilities may be exploited for selective therapeutic targeting.

Targeting IGF-IR improves neoadjuvant chemotherapy efficacy in breast cancers with low IGFBP7 expression

There has been a long-standing interest in targeting the type 1 insulin-like growth factor receptor (IGF-1R) signaling system in breast cancer due to its key role in neoplastic proliferation and survival. However, no IGF-1R targeting agent has shown substantial clinical benefit in controlled phase 3 trials, and no biomarker has been shown to have clinical utility in the prediction of benefit from an IGF-1R targeting agent. IGFBP7 is an atypical insulin-like growth factor binding protein as it has a higher affinity for the IGF-1R than IGF ligands. We report that low IGFBP7 gene expression identifies a subset of breast cancers for which the addition of ganitumab, an anti-IGF-1R monoclonal antibody, to neoadjuvant chemotherapy, substantially improved the pathological complete response rate compared to neoadjuvant chemotherapy alone. The pCR rate in the chemotherapy plus ganitumab arm was 46.9% in patients in the lowest quartile of IGFBP7 expression, in contrast to only 5.6% in the highest quartile. Furthermore, high IGFBP7 expression predicted increased distant metastasis risk. If our findings are confirmed, decisions to halt the development of IGF-1R targeting drugs, which were based on disappointing results of prior trials that did not use predictive biomarkers, should be reviewed.

Repurposing metabolic regulators: antidiabetic drugs as anticancer agents

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

Association between intensive blood pressure lowering and stroke-free survival among patients with and without Diabetes

This study pooled data from SPRINT (Systolic Blood Pressure Intervention Trial) and ACCORD-BP (Action to Control Cardiovascular Risk in Diabetes Blood Pressure) trial to estimate the treatment effect of intensive BP on stroke prevention, and investigate whether stroke risk score impacted treatment effect. Of all the potential manifestations of the hypertension, the most severe outcomes were stroke or death. A composite endpoint of time to death or stroke (stroke-free survival [SFS]), whichever occurred first, was defined as the outcome of interest. Participants without prevalent stroke were stratified into stroke risk tertiles based on the predicted revised Framingham Stroke Risk Score. The stratified Cox model was used to calculate the hazard ratio (HR) for the intensive BP treatment. 834 (5.92%) patients had SFS events over a median follow-up of 3.68 years. A reduction in the risk for SFS was observed among the intensive BP group as compared with the standard BP group (HR: 0.76, 95% CI: 0.65, 0.89; risk difference: 0.98([0.20, 1.76]). Further analyses demonstrated the significant benefit of intensive BP treatment on SFS only among participants having a high stroke risk (risk tertile 1: 0.76 [0.52, 1.11], number needed to treat [NNT] = 861; risk tertile 2: 0.87[0.65, 1.16], NNT = 91; risk tertile 3: 0.69[0.56, 0.86], NNT = 50). Intensive BP treatment lowered the risk of SFS, particularly for those at high risk of stroke.

Breast cancer incidence and mortality by metabolic syndrome and obesity: The Women's Health Initiative

BACKGROUND

In the Women's Health Initiative (WHI) randomized trial, dietary intervention significantly reduced breast cancer mortality, especially in women with more metabolic syndrome (MetS) components. Therefore, this study investigated the associations of MetS and obesity with postmenopausal breast cancer after long-term follow-up in the WHI clinical trials.

METHODS

A total of 68,132 postmenopausal women, without prior breast cancer and with normal mammogram, were entered into WHI randomized clinical trials; 63,330 women with an entry MetS score comprised the study population. At entry, body mass index (BMI) was determined; MetS score (0, 1-2, and 3-4) included the following: (1) high waist circumference (≥88 cm), (2) high blood pressure (systolic ≥130 mm Hg and/or diastolic ≥85 mm Hg, or hypertension history), (3) high-cholesterol history, and (4) diabetes history. Study outcomes included breast cancer incidence, breast cancer mortality, deaths after breast cancer, and results by hormone receptor status.

RESULTS

After a >20-year mortality follow-up, a higher MetS score (3-4), adjusted for BMI, was significantly associated with more poor prognosis, estrogen receptor (ER)-positive, progesterone receptor (PR)-negative cancers (p = .03), 53% more deaths after breast cancer (p < .001), and 44% higher breast cancer mortality (p = .03). Obesity status, adjusted for MetS score, was significantly associated with more good prognosis, ER-positive, PR-positive cancers (p < .001), more total breast cancers (p < .001), and more deaths after breast cancer (p < .001), with higher breast cancer mortality only in women with severe obesity (BMI, ≥35 kg/m2; p < .001).

CONCLUSIONS

MetS and obesity status have independent, but differential, adverse associations with breast cancer receptor subtypes and breast cancer mortality risk. Both represent separate targets for breast cancer prediction and prevention strategies.

Blocking tumor-intrinsic MNK1 kinase restricts metabolic adaptation and diminishes liver metastasis

Dysregulation of the mitogen-activated protein kinase interacting kinases 1/2 (MNK1/2)-eukaryotic initiation factor 4E (eIF4E) signaling axis promotes breast cancer progression. MNK1 is known to influence cancer stem cells (CSCs); self-renewing populations that support metastasis, recurrence, and chemotherapeutic resistance, making them a clinically relevant target. The precise function of MNK1 in regulating CSCs, however, remains unexplored. Here, we generated MNK1 knockout cancer cell lines, resulting in diminished CSC properties in vitro and slowed tumor growth in vivo. Using a multiomics approach, we functionally demonstrated that loss of MNK1 restricts tumor cell metabolic adaptation by reducing glycolysis and increasing dependence on oxidative phosphorylation. Furthermore, MNK1-null breast and pancreatic tumor cells demonstrated suppressed metastasis to the liver, but not the lung. Analysis of The Cancer Genome Atlas (TCGA) data from breast cancer patients validated the positive correlation between MNK1 and glycolytic enzyme protein expression. This study defines metabolic perturbations as a previously unknown consequence of targeting MNK1/2, which may be therapeutically exploited.

The Potential Impact of HNRNPA2B1 on Human Cancers Prognosis and Immune Microenvironment

HNRNPA2B1 is a member of the HNRNP family, which is associated with telomere function, mRNA translation, and splicing, and plays an important role in tumor development. To date, there have been no pan-cancer studies of HNRNPA2B1, particularly within the TME. Therefore, we conducted a pan-cancer analysis of HNRNPA2B1 using TCGA data. Based on datasets from TCGA, TARGET, Genotype-Tissue Expression, and Human Protein Atlas, we employed a range of bioinformatics approaches to explore the potential oncogenic role of HNRNPA2B1. This included analyzing the association of HNRNPA2B1 expression with prognosis, tumor mutation burden (TMB), microsatellite instability (MSI), immune response, and immune cell infiltration of individual tumors. We further validated the bioinformatic findings using immunohistochemistry techniques. HNRNPA2B1 was found to be differentially expressed across most tumor types in TCGA's pan-cancer database and was predictive of poorer clinical staging and survival status. HNRNPA2B1 expression was also closely linked to TMB, MSI, tumor stemness, and chemotherapy response. HNRNPA2B1 plays a significant role in the TME and is involved in the regulation of novel immunotherapies. Its expression is significantly associated with the infiltration of macrophages, dendritic cells, NK cells, and T cells. Furthermore, HNRNPA2B1 is closely associated with immune checkpoints, immune-stimulatory genes, immune-inhibitory genes, MHC genes, chemokines, and chemokine receptors. We performed a comprehensive evaluation of HNRNPA2B1, revealing its potential role as a prognostic indicator for patients and its immunomodulatory functions.

Rethinking about Metformin: Promising Potentials

Metformin is widely used drugs in the treatment of type 2 diabetes mellitus. However, the mechanisms of action are complex and are still not fully understood yet. Metformin has a dose-dependent blood sugar-lowering effect. The most common adverse reactions of metformin are gastrointestinal symptoms, and women tend to be more experienced than men. A positive correlation between the administration of duration and the daily dose of metformin and the risk of vitamin B12 deficiency is confirmed. Novel glucose-lowering mechanism through the activation of AMP-activated protein kinase and alteration of gut microbiota composition is identified. In addition, metformin has immunomodulatory properties in various mechanisms, including anti-inflammatory actions, and so forth. Metformin improves insulin sensitivity, which may reduce the risk of tumor growth in certain cancers. The antiviral effects of metformin may occur through several mechanisms, including blocking angiotensin converting enzyme 2 receptor, and so forth. These potential mechanisms of metformin are promising in various clinical settings, such as inflammatory diseases, autoimmune diseases, cancer, and coronavirus disease 2019.

Forkhead box protein FOXK1 disrupts the circadian rhythm to promote breast tumorigenesis in response to insulin resistance

The dysregulation of circadian rhythm oscillation is a prominent feature of various solid tumors. Thus, clarifying the molecular mechanisms that maintain the circadian clock is important. In the present study, we revealed that the transcription factor forkhead box FOXK1 functions as an oncogene in breast cancer. We showed that FOXK1 recruits multiple transcription corepressor complexes, including NCoR/SMRT, SIN3A, NuRD, and REST/CoREST. Among them, the FOXK1/NCoR/SIN3A complex transcriptionally regulates a cohort of genes, including CLOCK, PER2, and CRY2, that are critically involved in the circadian rhythm. The complex promoted the proliferation of breast cancer cells by disturbing the circadian rhythm oscillation. Notably, the nuclear expression of FOXK1 was positively correlated with tumor grade. Insulin resistance gradually became more severe with tumor progression and was accompanied by the increased expression of OGT, which caused the nuclear translocation and increased expression of FOXK1. Additionally, we found that metformin downregulates FOXK1 and exports it from the nucleus, while HDAC inhibitors (HDACi) inhibit the FOXK1-related enzymatic activity. Combined treatment enhanced the expression of circadian clock genes through the regulation of FOXK1, thereby exerting an antitumor effect, indicating that highly nuclear FOXK1-expressing breast cancers are potential candidates for the combined application of metformin and HDACi.

Metformin use and risk of myeloproliferative neoplasms: a Danish population-based case-control study

ABSTRACT

Previous studies have suggested that metformin has beneficial effects beyond its glucose-lowering properties, particularly in terms of its potential as an antineoplastic and cancer-preventive agent. In this study, we aimed to investigate the association between metformin use and the risk of myeloproliferative neoplasms (MPN). We conducted a population-based case-control study using Danish registers. Cases with MPN diagnosed between 2010 and 2018 were identified, and metformin use before the MPN diagnosis was ascertained. We compared metformin use among cases with MPN and an age- and sex-matched control group from the Danish general population to estimate age- and sex-adjusted odds ratios (ORs) and fully adjusted ORs (aORs) for the association between metformin use and risk of MPN. The study population included 3816 cases and 19 080 controls. Overall, 7.0% of cases and 8.2% of controls were categorized as ever-users of metformin, resulting in an OR for MPN of 0.84 (95% confidence interval [CI], 0.73-0.96) and an aOR of 0.70 (95% CI, 0.61-0.81). Long-term metformin use (≥5 years) was more infrequent and comprised 1.1% of cases and 2.0% of controls, resulting in an OR of 0.57 (95% CI, 0.42-0.79) and an aOR of 0.45 (95% CI, 0.33-0.63). A dose-response relationship was observed when cumulative duration of treatment was analyzed, and this was consistent in stratified analyses of sex, age, and MPN subtypes. In conclusion, metformin use was associated with significantly lower odds of an MPN diagnosis, indicating its potential cancer-preventive effect. Given the retrospective design, causality cannot be inferred.

The bioenergetic landscape of cancer

BACKGROUND

Bioenergetic remodeling of core energy metabolism is essential to the initiation, survival, and progression of cancer cells through exergonic supply of adenosine triphosphate (ATP) and metabolic intermediates, as well as control of redox homeostasis. Mitochondria are evolutionarily conserved organelles that mediate cell survival by conferring energetic plasticity and adaptive potential. Mitochondrial ATP synthesis is coupled to the oxidation of a variety of substrates generated through diverse metabolic pathways. As such, inhibition of the mitochondrial bioenergetic system by restricting metabolite availability, direct inhibition of the respiratory Complexes, altering organelle structure, or coupling efficiency may restrict carcinogenic potential and cancer progression.

SCOPE OF REVIEW

Here, we review the role of bioenergetics as the principal conductor of energetic functions and carcinogenesis while highlighting the therapeutic potential of targeting mitochondrial functions.

MAJOR CONCLUSIONS

Mitochondrial bioenergetics significantly contribute to cancer initiation and survival. As a result, therapies designed to limit oxidative efficiency may reduce tumor burden and enhance the efficacy of currently available antineoplastic agents.

Current type 2 diabetes guidelines: Individualized treatment and how to make the most of metformin

Evidence-based guidelines provide the premise for the delivery of quality care to preserve health and prevent disabilities and premature death. The systematic gathering of observational, mechanistic and experimental data contributes to the hierarchy of evidence used to guide clinical practice. In the field of diabetes, metformin was discovered more than 100 years ago, and with 60 years of clinical use, it has stood the test of time regarding its value in the prevention and management of type 2 diabetes. Although some guidelines have challenged the role of metformin as the first-line glucose-lowering drug, it is important to point out that the cardiovascular-renal protective effects of sodium-glucose co-transporter-2 inhibitors and glucagon-like peptide-1 receptor agonists were gathered from patients with type 2 diabetes, the majority of whom were treated with metformin. Most national, regional and international guidelines recommend metformin as a foundation therapy with emphasis on avoidance of therapeutic inertia and early attainment of multiple treatment goals. Moreover, real-world evidence has confirmed the glucose-lowering and cardiovascular-renal benefits of metformin accompanied by an extremely low risk of lactic acidosis. In patients with type 2 diabetes and advanced chronic kidney disease (estimated glomerular filtration rate 15-30 mL/min/1.73m2), metformin discontinuation was associated with an increased risk of cardiovascular-renal events compared with metformin persistence. Meanwhile, it is understood that microbiota, nutrients and metformin can interact through the gut-brain-kidney axis to modulate homeostasis of bioactive molecules, systemic inflammation and energy metabolism. While these biological changes contribute to the multisystem effects of metformin, they may also explain the gastrointestinal side effects and vitamin B12 deficiency associated with metformin intolerance. By understanding the interactions between metformin, foods and microbiota, healthcare professionals are in a better position to optimize the use of metformin and mitigate potential side effects. The United Kingdom Prospective Diabetes Study and the Da Qing Diabetes Prevention Program commenced 40 years ago provided the first evidence that type 2 diabetes is preventable and treatable. To drive real-world impact from this evidence, payors, practitioners and planners need to co-design and implement an integrated, data-driven, metformin-based programme to detect people with undiagnosed diabetes and prediabetes (intermediate hyperglycaemia), notably impaired glucose tolerance, for early intervention. The systematic data collection will create real-world evidence to bring out the best of metformin and make healthcare sustainable, affordable and accessible.

Metformin and other anti-diabetic medication use and breast cancer incidence in the Nurses' Health Studies

We aimed to examine the association between the use of metformin and other anti-diabetic medications and breast cancer incidence within two large prospective cohort studies. We followed 185,181 women who participated in the Nurses' Health Study (NHS; 1994-2016) and the NHSII (1995-2017), with baseline corresponding to the date metformin was approved for type 2 diabetes (T2D) treatment in the US Information on T2D diagnosis, anti-diabetes medications, and other covariates was self-reported at baseline and repeatedly assessed by follow-up questionnaires every 2 years. Breast cancer cases were self-reported and confirmed by medical record review. Hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between medication use and breast cancer were estimated using Cox proportional hazards regression models, adjusting for breast cancer risk factors. During 3,324,881 person-years of follow-up, we ascertained 9,192 incident invasive breast cancer cases, of which 451 were among women with T2D. Compared with women without T2D (n = 169,263), neither metformin use (HR = 0.97; 95% CI = 0.81-1.15) nor other anti-diabetic medications use (HR = 1.11; 95% CI = 0.90-1.36) associated with significantly lower breast cancer incidence. Among women with T2D (n = 15,918), compared with metformin never users, metformin ever use was not significantly inversely associated with breast cancer (HR = 0.92; 95% CI = 0.74-1.15). Although we observed that past use of metformin was inversely associated with breast cancer in the T2D population (HR = 0.67; 95% CI = 0.48-0.94), current use (HR = 1.01; 95% CI = 0.80-1.27) and longer duration of metformin use were not associated with breast cancer (each 2-year interval: HR = 1.01; 95% CI = 0.95-1.07). Overall, metformin use was not associated with the risk of developing breast cancer among the overall cohort population or among women with T2D.

Does metformin really reduce prostate cancer risk: an up-to-date comprehensive genome-wide analysis

BACKGROUND

The relationship between metformin use and prostate cancer (PCa) risk has yet to be clear despite more than a decade of debate on this topic. Hence, we aimed to investigate the causal role of metformin in reducing PCa risk through an up-to-date comprehensive genome-wide analysis.

METHODS

We employed validated instrument variables of metformin use derived from a prior high-quality study, including five potential targets (AMPK, GCG, GDF15, MCI and MG3). Mendelian randomization (MR) analysis was performed to harmonize genetically predicted metformin use and PCa phenotypes. PCa phenotypes were from two large genome-wide association studies (GWAS), the Prostate Cancer Association Group to Investigate Cancer-Associated Alterations in the Genome (PRACTICAL) and the FinnGen cohort. Seven methods were applied to generate MR results: the inverse variance weighted (IVW), IVW with multiplicative random effects, MR-Egger, MR-Egger (bootstrap), weighted median, simple mode and weighted mode. Strict sensitivity analysis was conducted to satisfy core assumptions of MR design.

RESULTS

We enrolled 32 significant single nucleotide polymorphisms (SNPs) that involved with metformin use. Nearly all targets yielded insignificant primary results (IVW with multiplicative random effects), except that AMPK target posed a positive effect on PCa risk from FinnGen cohort [odds ratio (OR): 6.09, 95% confidence interval (CI): 1.10-33.53, P value: 0.038]. The general effect of metformin use, comprising all 5 targets, also yielded negative results (random-effect meta-analysis with OR: 1.09, 95% CI: 0.76-1.58, P value: 0.637 for PRACTICAL; OR: 2.55, 95% CI: 0.58-11.16, P value: 0.215 for FinnGen). None of the sensitivity analyses provided support for a causal association between metformin use and PCa risk.

CONCLUSION

This up-to-date study did not support the protective role of metformin in reducing PCa risk, considering each target, overall effect, and sensitivity analysis. It is imperative to reflect on the presumed "almighty medicine" and ongoing phase III trials are anticipated to assess the anti-neoplasm effect of metformin.

Metformin Prevents Tumor Cell Growth and Invasion of Human Hormone Receptor-Positive Breast Cancer (HR+ BC) Cells via FOXA1 Inhibition

Women with type 2 diabetes (T2D) have a higher risk of being diagnosed with breast cancer and have worse survival than non-diabetic women if they do develop breast cancer. However, more research is needed to elucidate the biological underpinnings of these relationships. Here, we found that forkhead box A1 (FOXA1), a forkhead family transcription factor, and metformin (1,1-dimethylbiguanide hydrochloride), a medication used to treat T2D, may impact hormone-receptor-positive (HR+) breast cancer (BC) tumor cell growth and metastasis. Indeed, fourteen diabetes-associated genes are highly expressed in only three HR+ breast cancer cell lines but not the other subtypes utilizing a 53,805 gene database obtained from NCBI GEO. Among the diabetes-related genes, FOXA1, MTA3, PAK4, FGFR3, and KIF22 were highly expressed in HR+ breast cancer from 4032 breast cancer patient tissue samples using the Breast Cancer Gene Expression Omnibus. Notably, elevated FOXA1 expression correlated with poorer overall survival in patients with estrogen-receptor-positive/progesterone-receptor-positive (ER+/PR+) breast cancer. Furthermore, experiments demonstrated that loss of the FOXA1 gene inhibited tumor proliferation and invasion in vitro using MCF-7 and T47D HR+ breast cancer cell lines. Metformin, an anti-diabetic medication, significantly suppressed tumor cell growth in MCF-7 cells. Additionally, either metformin treatment or FOXA1 gene deletion enhanced tamoxifen-induced tumor growth inhibition in HR+ breast cancer cell lines within an ex vivo three-dimensional (3D) organoid model. Therefore, the diabetes-related medicine metformin and FOXA1 gene inhibition might be a new treatment for patients with HR+ breast cancer when combined with tamoxifen, an endocrine therapy.

Targeting cancer and immune cell metabolism with the complex I inhibitors metformin and IACS-010759

Metformin and IACS-010759 are two distinct antimetabolic agents. Metformin, an established antidiabetic drug, mildly inhibits mitochondrial complex I, while IACS-010759 is a new potent mitochondrial complex I inhibitor. Mitochondria is pivotal in the energy metabolism of cells by providing adenosine triphosphate through oxidative phosphorylation (OXPHOS). Hence, mitochondrial metabolism and OXPHOS become a vulnerability when targeted in cancer cells. Both drugs have promising antitumoral effects in diverse cancers, supported by preclinical in vitro and in vivo studies. We present evidence of their direct impact on cancer cells and their immunomodulatory effects. In clinical studies, while observational epidemiologic studies on metformin were encouraging, actual trial results were not as expected. However, IACS-01075 exhibited major adverse effects, thereby causing a metabolic shift to glycolysis and elevated lactic acid concentrations. Therefore, the future outlook for these two drugs depends on preventive clinical trials for metformin and investigations into the plausible toxic effects on normal cells for IACS-01075.

Repurposing Metformin for the Treatment of Atrial Fibrillation: Current Insights

Metformin is an orally effective anti-hyperglycemic drug that despite being introduced over 60 years ago is still utilized by an estimated 120 to 150 million people worldwide for the treatment of type 2 diabetes (T2D). Metformin is used off-label for the treatment of polycystic ovary syndrome (PCOS) and for pre-diabetes and weight loss. Metformin is a safe, inexpensive drug with side effects mostly limited to gastrointestinal issues. Prospective clinical data from the United Kingdom Prospective Diabetes Study (UKPDS), completed in 1998, demonstrated that metformin not only has excellent therapeutic efficacy as an anti-diabetes drug but also that good glycemic control reduced the risk of micro- and macro-vascular complications, especially in obese patients and thereby reduced the risk of diabetes-associated cardiovascular disease (CVD). Based on a long history of clinical use and an excellent safety record metformin has been investigated to be repurposed for numerous other diseases including as an anti-aging agent, Alzheimer's disease and other dementias, cancer, COVID-19 and also atrial fibrillation (AF). AF is the most frequently diagnosed cardiac arrythmia and its prevalence is increasing globally as the population ages. The argument for repurposing metformin for AF is based on a combination of retrospective clinical data and in vivo and in vitro pre-clinical laboratory studies. In this review, we critically evaluate the evidence that metformin has cardioprotective actions and assess whether the clinical and pre-clinical evidence support the use of metformin to reduce the risk and treat AF.

Bridging the gap: exploring the causal relationship between metformin and tumors

Objective

Numerous studies have reported that metformin can reduce the risk of tumor development. However, some of the results of these studies are conflicting, necessitating a more reliable evaluation.

Methods

We conducted a Mendelian randomization phenome-wide association study (MR-PheWAS) of tumors to explore the causal relationship between metformin and tumors. Two cohorts of patients taking metformin were obtained from the UK Biobank. Complete phenotype data of the tumors were obtained from FinnGen_R10. We elucidated the causal relationship using a two-sample Mendelian randomization (MR) analysis. More importantly, we conducted a meta-analysis to ensure relatively unbiased results. In the MR analysis, we used the inverse-variance weighted (IVW) method as the main outcome indicator. Subsequently, two cohorts were integrated for the meta-analysis. Finally, we investigated the mechanisms through mediational MR analysis.

Results

MR analysis revealed that metformin might have a causal relationship with 13 tumor-associated phenotypes in the training cohort. Four phenotypes were validated in the testing cohort. In the training and testing cohorts, metformin exhibited a protective effect against brain meningiomas and malignant neoplasms of the breast (HER-positive), oral cavity, tonsils, and the base of the tongue. Intriguingly, after integrating the results of the two cohorts for the meta-analysis, 12 results were statistically significant. Mediational MR analysis suggested that the effects of metformin on brain meningiomas may be weakened by the presence of the family Oxalobacteraceae.

Conclusion

Metformin exhibits potential preventive and therapeutic effects on four types of tumors: brain meningioma, malignant neoplasms of the breast (HER-positive), oral cavity and tonsils, and the base of the tongue. Large randomized controlled trials are required to confirm these findings.

New evidence: Metformin unsuitable as routine adjuvant for breast cancer: a drug-target mendelian randomization analysis

PURPOSE

The potential efficacy of metformin in breast cancer (BC) has been hotly discussed but never conclusive. This genetics-based study aimed to evaluate the relationships between metformin targets and BC risk.

METHODS

Metformin targets from DrugBank and genome-wide association study (GWAS) data from IEU OpenGWAS and FinnGen were used to investigate the breast cancer (BC)-metformin causal link with various Mendelian Randomization (MR) methods (e.g., inverse-variance-weighting). The genetic association between type 2 diabetes (T2D) and the drug target of metformin was also analyzed as a positive control. Sensitivity and pleiotropic tests ensured reliability.

RESULTS

The primary targets of metformin are PRKAB1, ETFDH and GPD1L. We found a causal association between PRKAB1 and T2D (odds ratio [OR] 0.959, P = 0.002), but no causal relationship was observed between metformin targets and overall BC risk (PRKAB1: OR 0.990, P = 0.530; ETFDH: OR 0.986, P = 0.592; GPD1L: OR 1.002, P = 0.806). A noteworthy causal relationship was observed between ETFDH and estrogen receptor (ER)-positive BC (OR 0.867, P = 0.018), and between GPD1L and human epidermal growth factor receptor 2 (HER2)-negative BC (OR 0.966, P = 0.040). Other group analyses did not yield positive results.

CONCLUSION

The star target of metformin, PRKAB1, does not exhibit a substantial causal association with the risk of BC. Conversely, metformin, acting as an inhibitor of ETFDH and GPD1L, may potentially elevate the likelihood of developing ER-positive BC and HER2-negative BC. Consequently, it is not advisable to employ metformin as a standard supplementary therapy for BC patients without T2D.

Ferritinophagy mediates adaptive resistance to EGFR tyrosine kinase inhibitors in non-small cell lung cancer

Osimertinib (Osi) is a widely used epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). However, the emergence of resistance is inevitable, partly due to the gradual evolution of adaptive resistant cells during initial treatment. Here, we find that Osi treatment rapidly triggers adaptive resistance in tumor cells. Metabolomics analysis reveals a significant enhancement of oxidative phosphorylation (OXPHOS) in Osi adaptive-resistant cells. Mechanically, Osi treatment induces an elevation of NCOA4, a key protein of ferritinophagy, which maintains the synthesis of iron-sulfur cluster (ISC) proteins of electron transport chain and OXPHOS. Additionally, active ISC protein synthesis in adaptive-resistant cells significantly increases the sensitivity to copper ions. Combining Osi with elesclomol, a copper ion ionophore, significantly increases the efficacy of Osi, with no additional toxicity. Altogether, this study reveals the mechanisms of NCOA4-mediated ferritinophagy in Osi adaptive resistance and introduces a promising new therapy of combining copper ionophores to improve its initial efficacy.

Cancer biology in diabetes update: Focusing on antidiabetic drugs

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

Clinical outcomes following discontinuation of metformin in patients with type 2 diabetes and advanced chronic kidney disease in Hong Kong: a territory-wide, retrospective cohort and target trial emulation study

Background

Current labelling advises discontinuation of metformin when estimated glomerular filtration rate (eGFR) < 30 ml/min/1.73 m2 due to increased risk of lactic acidosis. However, in real-world practice, the risk-benefit ratios remain uncertain. We examined the risk associations of discontinued-metformin use with cardiorenal and clinical outcomes in patients with type 2 diabetes (T2D) and advanced chronic kidney disease.

Methods

In this territory-wide, retrospective cohort and target trial emulation study, we included Chinese patients attending the Hong Kong Hospital Authority (HA) and enrolled in the Risk-Assessment-and-Management-Programme-for-Diabetes-Mellitus (RAMP-DM) from 2002 to 2019. Patients were stratified by discontinuation of metformin within six months after reaching eGFR < 30 ml/min/1.73 m2 from January 1, 2002 to December 31, 2018, and followed up until December 31 2019. We excluded patients who had observational time <6 months from eGFR < 30 ml/min/1.73 m2, and had their eGFR measured during a hospitalisation episode due to acute kidney injury, or missing diagnosis date of diabetes. We compared the risk associations of metformin discontinuation with clinical outcomes. The primary outcomes were major adverse cardiovascular events (MACE), end-stage kidney disease (ESKD), cancer, and all-cause mortality. A Cox-model with time-dependent exposure and covariates was used to estimate the hazard ratio (HR) of outcomes in a propensity-score overlap-weighted cohort. The risk of occurrence of lactic acidosis (serum lactate > 5.0 mmol/L with a concomitant blood pH < 7.35 or ICD-9 codes of 276.2) in discontinued-metformin versus continued-metformin users was assessed in a separate register-based cohort.

Findings

A total of 33,586 metformin users with new-onset eGFR < 30 ml/min/1.73 m2 were included in the study, 7500 (22.3%) of whom discontinued metformin within 6 months whereas 26,086 (77.7%) continued use of metformin. During a median follow-up of 3.8 (IQR: 2.2-6.1) years, 16.4% (5505/33,586), 30.1% (10,113/33,586), and 7.1% (2171/30,682) had incident MACE, ESKD, and cancer respectively, and 44.4% (14,917/33,586) died. Compared to continued-metformin use, discontinuation was associated with higher risk of MACE (weighted and adjusted HR = 1.40, 95% CI: 1.29-1.52), ESKD (HR = 1.52, 1.42-1.62), and death (HR = 1.22, 1.18-1.27). No association was observed for cancer (HR = 0.93, 0.85-1.01). Discontinued-metformin users had higher change in HbA1c change at 6-month of follow-up versus continued-metformin users (weighted mean HbA1c level change: 0.5% [0.4-0.6%] versus 0.2% [0.1-0.2]). In the separate register-based cohort (n = 3235), null association was observed between metformin use and risk of lactic acidosis (weighted HR = 0.94 [0.53-1.64]).

Interpretation

Our results suggest that discontinuation of metformin in patients with T2D and chronic kidney disease may be associated with increased risk of cardiovascular-renal events. Use of metformin below eGFR of 30 ml/min/1.73 m2 may be associated with cardiovascular, renal, and mortality benefits that need to be weighed against the risk of lactic acidosis, but further research is needed to validate these findings.

Funding

CUHK Impact Research Fellowship Scheme.

Effect of metformin and lifestyle intervention on adipokines and hormones in breast cancer survivors: a pooled analysis from two randomized controlled trials

PURPOSE

We investigated the effect of metformin and lifestyle intervention on metabolic, inflammatory, and steroid biomarkers of breast cancer (BC) recurrence risk in two intervention trials among BC survivors with overweight or obesity.

METHODS

Baseline and follow-up serum samples collected during the two trials were analyzed and data pooled. The USA trial (Reach for Health) included postmenopausal BC survivors (n = 333) randomly assigned to 6-month metformin vs placebo and lifestyle intervention (LSI) vs control (2 × 2 factorial design). The Italian trial (MetBreCS) included BC survivors (n = 40) randomized to 12-month metformin vs placebo. Insulin resistance (HOMA-IR), adipokines, cytokines, and steroids were measured.

RESULTS

Metformin compared to placebo showed a favorable decrease in leptin (- 8.8 vs - 3.5 ng/mL; p < 0.01) and HOMA-IR (- 0.48 vs - 0.25; p = 0.03), and an increase in SHBG (2.80 vs 1.45 nmol/L; p < 0.01). Excluding women taking aromatase inhibitors, metformin (n = 84) compared to placebo (n = 99) decreased estradiol (- 4 vs 0 pmol/L; p < 0.01), estrone (- 8 vs 2 pmol/L; p < 0.01) and testosterone (- 0.1 vs 0 nmol/L-; p = 0.02). LSI favorably affected adiponectin (0.45 vs - 0.06 ug/mL; p < 0.01), leptin (- 10.5 vs - 4.4 ng/mL; p < 0.01), HOMA-IR (- 0.6 vs 0.2; p = 0.03), and SHBG (2.7 vs 1.1 nMol/L; p = 0.04) compared to controls. The strongest impact was observed combining metformin with LSI on adipokines, CRP, SHBG, and estrogens.

CONCLUSIONS

Supportive healthy lifestyle programs combined with metformin to achieve maximal risk reduction among BC cancer survivors are recommended, especially for those with obesity in menopause.

Metformin: From Diabetes to Cancer-Unveiling Molecular Mechanisms and Therapeutic Strategies

Metformin, a widely used anti-diabetic drug, has garnered attention for its potential in cancer management, particularly in breast and colorectal cancer. It is established that metformin reduces mitochondrial respiration, but its specific molecular targets within mitochondria vary. Proposed mechanisms include inhibiting mitochondrial respiratory chain Complex I and/or Complex IV, and mitochondrial glycerophosphate dehydrogenase, among others. These actions lead to cellular energy deficits, redox state changes, and several molecular changes that reduce hyperglycemia in type 2 diabetic patients. Clinical evidence supports metformin's role in cancer prevention in type 2 diabetes mellitus patients. Moreover, in these patients with breast and colorectal cancer, metformin consumption leads to an improvement in survival outcomes and prognosis. The synergistic effects of metformin with chemotherapy and immunotherapy highlights its potential as an adjunctive therapy for breast and colorectal cancer. However, nuanced findings underscore the need for further research and stratification by molecular subtype, particularly for breast cancer. This comprehensive review integrates metformin-related findings from epidemiological, clinical, and preclinical studies in breast and colorectal cancer. Here, we discuss current research addressed to define metformin's bioavailability and efficacy, exploring novel metformin-based compounds and drug delivery systems, including derivatives targeting mitochondria, combination therapies, and novel nanoformulations, showing enhanced anticancer effects.

Drug repurposing for cancer therapy

Cancer, a complex and multifactorial disease, presents a significant challenge to global health. Despite significant advances in surgical, radiotherapeutic and immunological approaches, which have improved cancer treatment outcomes, drug therapy continues to serve as a key therapeutic strategy. However, the clinical efficacy of drug therapy is often constrained by drug resistance and severe toxic side effects, and thus there remains a critical need to develop novel cancer therapeutics. One promising strategy that has received widespread attention in recent years is drug repurposing: the identification of new applications for existing, clinically approved drugs. Drug repurposing possesses several inherent advantages in the context of cancer treatment since repurposed drugs are typically cost-effective, proven to be safe, and can significantly expedite the drug development process due to their already established safety profiles. In light of this, the present review offers a comprehensive overview of the various methods employed in drug repurposing, specifically focusing on the repurposing of drugs to treat cancer. We describe the antitumor properties of candidate drugs, and discuss in detail how they target both the hallmarks of cancer in tumor cells and the surrounding tumor microenvironment. In addition, we examine the innovative strategy of integrating drug repurposing with nanotechnology to enhance topical drug delivery. We also emphasize the critical role that repurposed drugs can play when used as part of a combination therapy regimen. To conclude, we outline the challenges associated with repurposing drugs and consider the future prospects of these repurposed drugs transitioning into clinical application.

Metformin: A Dual-Role Player in Cancer Treatment and Prevention

Cancer continues to pose a significant global health challenge, as evidenced by the increasing incidence rates and high mortality rates, despite the advancements made in chemotherapy. The emergence of chemoresistance further complicates the effectiveness of treatment. However, there is growing interest in the potential of metformin, a commonly prescribed drug for type 2 diabetes mellitus (T2DM), as an adjuvant chemotherapy agent in cancer treatment. Although the precise mechanism of action of metformin in cancer therapy is not fully understood, it has been found to have pleiotropic effects, including the modulation of metabolic pathways, reduction in inflammation, and the regulation of cellular proliferation. This comprehensive review examines the anticancer properties of metformin, drawing insights from various studies conducted in vitro and in vivo, as well as from clinical trials and observational research. This review discusses the mechanisms of action involving both insulin-dependent and independent pathways, shedding light on the potential of metformin as a therapeutic agent for different types of cancer. Despite promising findings, there are challenges that need to be addressed, such as conflicting outcomes in clinical trials, considerations regarding dosing, and the development of resistance. These challenges highlight the importance of further research to fully harness the therapeutic potential of metformin in cancer treatment. The aims of this review are to provide a contemporary understanding of the role of metformin in cancer therapy and identify areas for future exploration in the pursuit of effective anticancer strategies.