Metformin and Breast Cancer: Where Are We Now?

Metformin upregulates circadian gene PER2 to inhibit growth and enhance the sensitivity of glioblastoma cell lines to radiotherapy via SIRT2/G6PD pathway

Introduction

Glioblastoma multiform (GBM) is considered the deadliest brain cancer. Standard therapies are followed by poor patient's survival outcomes, so novel and more efficacious therapeutic strategies are imperative to tackle this scourge. Metformin has been reported to have anti-cancer effects. However, the precise mechanism underlying these effects remains elusive. A better understanding of its underlying mechanism will inform future experimental designs exploring metformin as a potential adjuvant therapy for GBM. This research aimed to elucidate the potential molecular mechanism of metformin in GBM by integrating proteomics and transcriptomics.

Methods

The study examined the effects of metformin on GBM cell lines using various methods. The U87, U251 and HA1800 were cultured and modified through PER2 knockdown and overexpression. Cell viability was assessed using the CCK8 assay, and G6PDH activity and intracellular NADPH+ levels were measured with specific kits. ROS levels, mitochondrial membrane potential, cell cycle distribution and apoptosis were analyzed by flow cytometry. RNA was extracted for transcriptomic analysis through RNA sequencing, while proteomic analysis was performed on total protein from treated cells. WB detected specific proteins, and RT-qPCR quantified gene expression. In vivo experiments, GBM xenograft on nude mice treated with metformin combining radiotherapy was evaluated and received IHC and TUNEL staining for protein expression and apoptosis assessment. Statistical analyses were conducted using Prism software to identify significant group differences.

Results

We found that differential expressional genes and proteins relating to circadian rhythm were enriched in proteomic or transcriptomic. The expression of PER2, the key circadian gene, was up-regulated in GBM cell lines when treated with metformin. Furthermore, the expression of silent information regulator 2(SIRT2) was down-regulated, while the expression of the G6PD protein just slightly increased in GBM cell lines. Meanwhile, NADPH+ production and G6PDH enzyme activity significantly decreased. Further study validated that metformin inhibited the cell growth of GBM cell lines through up-regulating PER2 and inhibited SIRT2/G6PD signaling pathway, enhancing radiotherapy(RT) sensitivity. We also found that the inhibition of SIRT2 caused by metformin is mediated by PER2.

Discussion

We found the pivotal role of metformin as an effective circadian rhythm regulator. Targeting circadian clock gene to modify and rescue the dysfunctional circadian clock of GBM cells at molecular level might be an innovative way to administer cancer chronotherapy and maintain metabolic homeostasis in real world practice.

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.

Niosomes as a targeted drug delivery system in the treatment of breast cancer: preparation, classification and mechanisms of cellular uptake

Breast cancer (BC) remains one of the significant health issues across the globe, being diagnosed in millions of women worldwide annually. Conventional therapeutic options have substantial adverse effects due to their non-specificity and limited drug bioavailability. Niosomes, being novel drug delivery systems formed from non-ionic surfactants, with or without cholesterol and charge-inducing agents, are used as therapeutic options in treating BC. Their formulation by various methods enhances the therapeutic efficacy and bioavailability and minimises side effects. Niosomal formulation of tamoxifen exhibits target drug delivery with enhanced stability, whereas docetaxel and methotrexate show sustained and controlled drug release, respectively. 5-Fluorouracil, doxorubicin, paclitaxel, cyclophosphamide and epirubicin show improved cytotoxic effects against BC when combined with other agents. Furthermore, repurposed niosomal formulations of anti-cancer drugs show improved penetration, reduced tumour volume and significantly enhanced anti-tumour effect. This review article focuses on the composition of niosomes and their application in BC treatment and then examines how niosomes could contribute to BC research.

Metformin-induced RBMS3 expression enhances ferroptosis and suppresses ovarian cancer progression

Metformin (Met), a widely used type II diabetes medication, has shown anti-cancer properties in various cancers. RBMS3 is a tumor suppressor implicated in several cancers, including ovarian cancer. Ferroptosis, a novel form of programmed cell death, is gaining attention in cancer research. This study explores whether metformin induces ferroptosis and inhibits ovarian cancer progression through the RBMS3 pathway. We used a CCK-8 assay to determine the optimal metformin concentration for ovarian cancer cells. Metformin's effects were further evaluated using EdU assay and flow cytometry. To clarify its mechanism, we employed programmed cell death inhibitors and measured levels of MDA (Malondialdehyde), GSH (Glutathione), and Fe²⁺. Ferroptosis-related proteins and RBMS3 expression in ovarian cancer tissues and cells were assessed via RT-qPCR and Western blotting. A xenograft mouse model was used to observe metformin's effects on tumor growth. Metformin inhibited the viability of ovarian cancer A2780 cells, promoted ferroptosis, increased MDA and Fe²⁺ levels, and reduced GSH. It upregulated ferroptosis-related genes while downregulating GPX4 and SLC7A11. Although RBMS3 was reduced in cancer cells, metformin increased its expression, and silencing RBMS3 reversed metformin's effects. In vivo, metformin inhibited tumor growth, which was negated by RBMS3 silencing. Our findings suggest that metformin promotes ferroptosis and inhibits ovarian cancer progression by upregulating RBMS3, offering a promising direction for clinical application in ovarian cancer treatment.

Metformin combined with paclitaxel chemotherapy for patients with type 2 diabetes mellitus and esophageal cancer: Clinical efficacy and impact on blood glucose levels and tumor markers

BACKGROUND

Metformin is a first-line drug for type 2 diabetes, and paclitaxel is a commonly used chemotherapy drug for esophageal cancer. For patients with type 2 diabetes mellitus (T2DM) and esophageal cancer, both anti-tumor therapy and control of blood sugar are required. The combined application of metformin and paclitaxel chemotherapy may enhance treatment efficacy in patients with T2DM and esophageal cancer.

AIM

To evaluate the clinical effects of metformin combined with paclitaxel chemotherapy in patients with T2DM and esophageal cancer, and to analyze its impact on blood glucose levels and tumor markers.

METHODS

A total of 200 patients with T2DM and esophageal cancer admitted to our hospital from October 2018 to October 2022 were selected. These patients were divided into a study group and a control group according to the treatment plan, with 100 cases in each group. Both groups received basic glucose control and chemoradiotherapy. The control group was additionally treated with paclitaxel chemotherapy, while the study group additionally received a combination therapy of metformin and paclitaxel chemotherapy. The therapeutic effects, glucose levels [fasting blood glucose (FBG), 2 h postprandial blood glucose (2 h PBG), and hemoglobin A1c (HbAlc)], tumor marker levels [carbohydrate antigen72-4 (CA724), cytokeratin 19 fragment (CYFRA21-1), squamous cell carcinoma associated antigen (SCC), and carcinoembryonic antigen (CEA)], miR-126 and miR-21 levels, adverse reactions, and survival rates were compared between the two groups.

RESULTS

After 1 and 3 cycles of treatment, the levels of FBG, 2 h PBG, and HbAlc in both groups were lower than those before treatment, and the levels of these indexes in the study group were lower than those of the control group. The levels of FBG, 2 h PBG, and HbAlc in the control group after 3 cycles of treatment were higher than those after 1 cycle of treatment (P < 0.05). After 1 and 3 cycles of treatment, serum levels of SCC, CA724, CEA, and CYFRA21-1 in both groups were decreased compared with those before treatment, and these indexes in the study group were lower than those of the control group (P < 0.05). After 1 and 3 cycles of treatment, the serum miR-126 level in both groups was higher than that before treatment, and the serum miR-21 level was lower than that before treatment; the serum miR-126 level in the study group was higher than that of the control group, and the serum miR-21 level was lower than that of the control group (P < 0.05). After 3 cycles of treatment, the disease control rate (DCR) and objective response rate (ORR) in the study group were higher than those of the control group (P < 0.05). During the 1-year follow-up, 3 patients in the study group and 2 in the control group were lost to follow-up due to residence address changes. The DCR in the study group was higher than that of the control group (P < 0.05), but there was no significant difference in ORR between the two groups (P > 0.05). After one-year follow-up, there was no statistically significant difference in adverse reactions between the two groups (P > 0.05). There was no significant difference in the 6-month survival rate between the two groups (P > 0.05), while the 1-year survival rate in the study group was higher than that of the control group (P < 0.05).

CONCLUSION

Metformin combined with paclitaxel chemotherapy has remarkable efficacy in patients with T2DM and esophageal cancer, which can effectively improve blood glucose levels, and regulate the levels of tumor markers and the expression of miR-126 and miR-21, thus being conducive to prolonging the survival time of patients. This combination therapy has an acceptable safety pofile.

Life's Essential 8 and Cardiovascular Disease in Breast Cancer Survivors

PURPOSE OF REVIEW

To explore the role of optimal cardiovascular health as defined by the Life's Essential 8 in breast cancer survivors.

RECENT FINDINGS

Optimal cardiovascular health may be associated with decreased cancer mortality. Breast cancer survivors may derive additional benefit from obtaining ideal cardiovascular health as defined by the Life's Essential 8. Certain components of the Life's Essential 8 may impact cardiovascular risk but also cancer mortality, and risk for cancer therapy related cardiac dysfunction. Continued physical activity, avoidance of smoking, and control of lipids and blood pressure are beneficial in breast cancer survivors. More study is needed to define the role of anti-hyperglycemic agents, BMI, and sleep on CVD risk in breast cancer survivors. The Life's Essential 8 can be a tool to inform clinicians regarding a breast cancer survivor's disease risk and to identify potential areas of improvement.

Global disease burden of breast cancer attributable to high fasting plasma glucose: a comprehensive analysis from the global burden of disease study

Background

High fasting plasma glucose (HFPG) has been identified as one of the risk factors associated with the development of breast cancer. The worldwide distribution of breast cancer attributable to HFPG was not comprehensively investigated.

Methods

We utilized the data from the Global Burden of Disease Study 2021 to explore HFPG-related breast cancer deaths, disability adjusted life years (DALYs) and corresponding age-standardized rates (ASRs). The average annual percentage change (AAPC) and the estimated annual percentage change (EAPC) were employed to evaluate the temporal trend.

Results

The global effect of HFPG resulted in nearly 30,570 breast cancer deaths and 819,550 DALYs in 2021, representing an age-standardized deaths rate (ASMR) of 0.66 (95% UI -0.19-1.57) and an age-standardized DALYs rate (ASDR) of 18.05 (95% UI -5.31-42.71). In the regions with low, low-middle, and middle SDI, the ASRs of HFPG-related breast cancer increased significantly over time. The highest ASMR and ASDR were observed in several countries, such as Palau, American Samoa, Cook Islands, Marshall Islands, and United Arab Emirates. There was a positive correlation between ASRs and Socio-Demographic Index (SDI) in countries where SDI was below 0.75. The escalation in death and DALYs was primarily driven by epidemiological change and population growth in low, low-middle, middle SDI regions.

Conclusions

Substantial disparities exist across diverse regions in breast cancer burden attributed to HFPG. It is urgent to regulate glycemic levels, improve healthcare infrastructures, and provide cost-effective care in less developed and developing countries that endure a disproportionately heavier health burden.

Metformin-encapsulating immunoliposomes conjugated with anti-TROP 2 antibody fragments for the active targeting of triple-negative breast cancer

Trophoblast cell-surface antigen 2 (TROP 2) has re-emerged as a promising biomarker in triple-negative breast cancer (TNBC), with high overexpression in many TNBC cases. However, despite its potential and approval as an antibody-drug-conjugate for TNBC treatment, TROP 2-targeted delivery systems are currently underexplored. Therefore, this study was aimed at exploiting the potential of TROP 2 targeting by encapsulating metformin (Met), an antidiabetic drug associated with tumor growth inhibitory properties, inside liposomes decorated with TROP 2-targeting single-chain variable fragments (scFvs). The optimization of scFv grafting resulted in Met-immunoliposomes with an average diameter of less than 200 nm, low polydispersity index (∼0.1), negative surface charge (<-10 mV), high Met drug loading (>150 mg g-1), and high affinity towards TROP 2 binding. Furthermore, Met-immunoliposomes were reproducible, and the scFv conjugation was stable in the presence of serum for five days. Their cellular uptake increased 4 folds in two-dimensional and 9 folds in three-dimensional TNBC models owing to the high affinity towards TROP 2 binding. Finally, it was observed that the therapeutic effect of Met in suppressing cancer cell growth and proliferation was superior when using anti-TROP 2 scFv-grafted Met-immunoliposomes, which completely stopped the spheroid growth and inhibited the expression of adenosine triphosphate. This study is one of the first reports to explore the combination of nanoparticle-based drug delivery systems to target the TROP 2 protein in TNBC, and to the best of our knowledge, this is the first report to specifically combine the use of scFvs with TROP 2 targeting to deliver therapeutics for TNBC treatment.

Breast Cancer Risk and Management in the Endocrine Clinic: A Comprehensive Review

OBJECTIVE

This review seeks to provide endocrine clinicians with a comprehensive analysis of breast cancer risk, diagnostic modalities and management strategies in women with endocrine disorders, with particular emphasis on the influence of metabolic factors such as diabetes and obesity, and the role of Menopausal Hormone Therapy (MHT).

DESIGN

The review examines a spectrum of endocrine disorders commonly encountered in clinical practice, including Multiple Endocrine Neoplasia Types 1 (MEN1), 2 (MEN2) and 4 (MEN4), Von Hippel-Lindau syndrome (VHL), Pheochromocytoma and Paraganglioma (PPGL), Acromegaly, Hyperprolactinaemia, Polycystic Ovary Syndrome (PCOS), Congenital Adrenal Hyperplasia (CAH), Turner Syndrome, alongside metabolic conditions such as diabetes and obesity and the effects of MHT. The review critically appraises each disorder's association with breast cancer risk, screening implications and therapeutic management.

PATIENTS

This analysis focuses on women with the aforementioned endocrine and metabolic disorders, assessing their specific breast cancer risk profiles, informed by the latest clinical evidence and molecular insights.

MEASUREMENTS

The review comprehensively evaluates current evidence-based approaches to screening, diagnostic accuracy and treatment in this patient cohort. Emphasis is placed on the metabolic derangements, hormonal influences and genetic predispositions that modulate breast cancer risk, providing disorder-specific recommendations for individualised care.

RESULTS

The findings indicate a significantly elevated breast cancer risk in patients with MEN1, necessitating early initiation of MRI screening by age 40. In MEN2, emerging evidence suggests that combining RET inhibitors with endocrine therapy may yield clinical benefits, although further research is needed to validate this approach. The breast cancer risk associated with MEN4 and VHL syndromes, while documented, remains less well-characterised, requiring further investigation. Diabetes and obesity are confirmed as major modifiable risk factors, particularly in postmenopausal women, where hyperinsulinemia and metabolic dysfunction contribute to increased incidence and poorer outcomes, notably in triple-negative breast cancer (TNBC). The role of MHT, particularly combined oestrogen-progestogen therapy, is strongly associated with increased breast cancer risk, particularly for hormone receptor-positive malignancies, necessitating cautious use and personalised treatment planning. In contrast, oestrogen-only MHT appears to confer a reduced risk in women post-hysterectomy. For patients with PCOS, CAH and Turner Syndrome, while definitive evidence of elevated breast cancer risk is lacking, individualised screening strategies and careful hormone therapy management remain essential due to the complex interplay of hormonal and metabolic factors.

CONCLUSIONS

The review highlights the need for personalised breast cancer screening and management protocols in women with endocrine and metabolic disorders. For high-risk groups such as MEN1 patients, early initiation of MRI screening is warranted. In women with diabetes and obesity, targeted interventions addressing hyperinsulinemia and metabolic dysfunction are critical to mitigating their increased cancer risk. The association between MHT and breast cancer underscores the importance of individualised risk stratification in hormone therapy administration, particularly in women with predisposing genetic or endocrine conditions. Enhanced surveillance tailored to the unique risk profiles of endocrine disorder patients will facilitate early detection and improve clinical outcomes. However, further large-scale studies are necessary to refine these associations and develop robust, evidence-based guidelines.

Respiratory complex I-mediated NAD+ regeneration regulates cancer cell proliferation through the transcriptional and translational control of p21Cip1 expression by SIRT3 and SIRT7

The role of the electron transport chain (ETC) in cell proliferation control beyond its crucial function in supporting ATP generation has recently emerged. In this study, we found that, among the four ETC complexes, the complex I (CI)-mediated NAD+ regeneration is important for cancer cell proliferation. In cancer cells, a decrease in CI activity by RNA interference (RNAi) against NADH:ubiquinone oxidoreductase core subunit V1 (NDUFV1) arrested the cell cycle at the G1/S phase, accompanying upregulation of p21Cip1 cyclin-dependent kinase inhibitor expression. Mechanistically, a decrease in the NAD+/NADH ratio downregulated SIRT3 and SIRT7 function, which suppressed p21Cip1 expression at the translational and transcriptional levels, respectively, resulting in the upregulation of the antiproliferative molecule. Importantly, high expression levels of the core subunits of CI correlated with poor prognosis in patients with the hormone receptor(+)/human epidermal growth factor receptor 2(-) (HR+/HER2-) subtype of breast cancer. Therefore, NDUFV1 and SIRT3/7 have emerged as promising therapeutic targets against this breast cancer subtype.

Investigation of potential anti-metastatic effect of metformin and caffeic acid combination therapy in breast cancer cell line in in-vitro culture model

The invasion and metastasis of cancer cells transform localized cancers into systemic and life-threatening diseases, posing one of the most significant challenges in cancer treatment. This study tested the hypothesis that combined treatment with Caffeic acid (CA) and metformin (MTF) could inhibit or reduce effective signaling pathways involved in the proliferation, survival, and metastasis of MCF-7 breast cancer cells. Anti-proliferation analysis determined the IC50 values for MTF (4.5 mM) and CA (163 µM) after 72 h. Cell migration analysis showed that MTF and CA significantly inhibited MCF-7 cell migration by the 72nd hour, both alone and in combination, without affecting HME1 healthy cell migration from the 48th hour. Colony formation analysis revealed that CA completely inhibited colony formation in MCF-7 cells, while MTF reduced it by 19%. ELISA results indicated that neither CA nor MTF affected the levels of VEGF-A, E-cadherin, or TINAGL-1 proteins, which are involved in MCF-7 cell migration and invasion. However, MTF significantly reduced IL-1β protein levels, and CA significantly reduced IL-4 protein levels in MCF-7 cells. RT-qPCR results largely supported the ELISA findings. Overall, CA and MTF exhibited potential to inhibit MCF-7 cell apoptosis, migration, tumor microenvironment modulation, and metastasis.

Design, optimization, characterization, and in vitro evaluation of metformin-loaded liposomes for triple negative breast cancer treatment

Recently, metformin (Met) has shown to have antineoplastic properties in cancer treatment by improving hypoxic tumor conditions, and causing reduction in the synthesis of biomolecules, which are vital for cancer growth. However, as an orally administered drug, Met has low bioavailability and rapid renal clearance. Thus, the goal of this study was to vectorize Met inside liposomes in the context of triple negative breast cancer (TNBC), which currently lacks treatment options when compared to other types of breast cancer. Vectorization of Met inside liposomes was done using Bangham method by implementing double design of experiment methodology to increase Met drug loading (minimum-run resolution V characterization design and Box-Behnken design), as it is generally extremely low for hydrophilic molecules. Optimization of Met-loaded liposome synthesis was successfully achieved with drug loading of 190 mg/g (19% w/w). The optimal Met-liposomes were 170 nm in diameter with low PdI (< 0.1) and negative surface charge (-20 mV), exhibiting sustained Met release at pH 7.4. The liposomal Met delivery system was stable over several months, and successfully reduced TNBC cell proliferation due to the encapsulated drug. This study is one the first reports addressing liposome formulation through thin-film hydration using two design of experiment methods aiming to increase drug loading of Met.

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.

Global, reginal, national burden and risk factors in female breast cancer from 1990 to 2021

This study was to assess the burden, trends, and risk factors associated with female breast cancer from 1990 to 2021 based on the Global Burden of Disease (GBD) 2021 study. In 2021, there were 20.32 million prevalent cases, 2.08 million incident cases, 0.66 million death cases, and 20.26 million disability-adjusted life years (DALYs). It presented an ascending trend in the age-standardized rates of prevalence and incidence over the past 32 years. The age-standardized DALYs rate (ASDR) increased slightly during 2012-2021. The DALYs increase was primarily driven by population aging and growth. High red meat intake accounted for the highest proportion of ASDR. Breast cancer burden attributed to metabolic risks increased, especially in the regions with low social-development index (SDI) and limited health systems. Dietary, behavior, and metabolic risk factors should be controlled to diminish breast cancer burden, especially in countries with lower SDI.

Intermediate Filaments in Breast Cancer Progression, and Potential Biomarker for Cancer Therapy: A Narrative Review

Intermediate filaments are one of the three components of the cytoskeletons, along with actin and microtubules. The intermediate filaments consist of extensive variations of structurally related proteins with specific expression patterns in cell types. The expression pattern alteration of intermediate filaments is frequently correlated with cancer progression, specifically with the epithelial-to-mesenchymal transition process closely related to increasing cellular migration and invasion. This review will discuss the involvement of cytoplasmic intermediate filaments, specifically vimentin, nestin, and cytokeratin (CK5/CK6, CK7, CK8/CK18, CK17, CK19, CK20, CSK1), in breast cancer progression and as prognostic or diagnostic biomarkers. The potential for drug development targeting intermediate filaments in cancer will be reviewed.

Metformin: Beyond Type 2 Diabetes Mellitus

Metformin was developed from an offshoot of Guanidine. It is known to be the first-line medication for type 2 diabetes mellitus, polycystic ovarian syndrome, and weight reduction. Metformin has also been shown to have effectiveness in the management of non-alcoholic fatty liver disease (NAFLD), liver cirrhosis, and various carcinomas like hepatocellular, colorectal, prostate, breast, urinary bladder, blood, melanoma, bone, skin, lung and so on. This narrative review focuses on the effect of metformin on non-alcoholic fatty liver disease, liver cirrhosis, and hepatocellular carcinoma. The search platforms for the topic were PubMed, Scopus, and Google search engine. Critical words for searching included 'Metformin,' AND 'Indications of Metformin,' AND 'Non-Alcoholic Fatty Liver Disease,' AND 'Metformin mechanism of action,' AND 'NAFLD management,' AND 'NAFLD and inflammation,' AND 'Metformin and insulin,' AND 'Metformin and inflammation,' AND 'Liver cirrhosis,' AND 'Hepatocellular carcinoma.' Lifestyle modification and the use of hypoglycemic agents can help improve liver conditions. Metformin has several mechanisms that enhance liver health, including reducing reactive oxygen species, nuclear factor kappa beta (NF-κB), liver enzymes, improving insulin sensitivity, and improving hepatic cell lipophagy. Long-term use of metformin may cause some adverse effects like lactic acidosis and gastrointestinal disturbance. Metformin long-term overdose may lead to a rise in hydrogen sulfide in liver cells, which calls for pharmacovigilance. Drug regulating authorities should provide approval for further research, and national and international guidelines need to be developed for liver diseases, perhaps with the inclusion of metformin as part of the management regime.

Emerging role of necroptosis, pyroptosis, and ferroptosis in breast cancer: New dawn for overcoming therapy resistance

Breast cancer (BC) is one of the primary causes of death in women worldwide. The challenges associated with adverse outcomes have increased significantly, and the identification of novel therapeutic targets has become increasingly urgent. Regulated cell death (RCD) refers to a type of cell death that can be regulated by several different biomacromolecules, which is distinctive from accidental cell death (ACD). In recent years, apoptosis, a representative RCD pathway, has gained significance as a target for BC medications. However, tumor cells exhibit avoidance of apoptosis and result in treatment resistance, which emphasizes further studies devoted to alternative cell death processes, namely necroptosis, pyroptosis, and ferroptosis. Here, in this review, we focus on summarizing the crucial signaling pathways of these RCD in BC. We further discuss the molecular mechanism and potentiality in clinical application of several prospective drugs, nanoparticles, and other small compounds targeting different RCD subroutines of BC. We also discuss the benefits of modulating RCD processes on drug resistance and the advantages of combining RCD modulators with conventional treatments in BC. This review will deepen our understanding of the relationship between RCD and BC, and shed new light on future directions to attack cancer vulnerabilities with RCD modulators for therapeutic purposes.

METFORMIN: FROM DIABETES TO CANCER TO PROLONGATION OF LIFE

The metformin molecule dates back to over a century, but its clinical use started in the '50s. Since then, its use in diabetics has grown constantly, with over 150 million users today. The therapeutic profile also expanded, with improved understanding of novel mechanisms. Metformin has a major activity on insulin resistance, by acting on the insulin receptors and mitochondria, most likely by activation of the adenosine monophosphate-activated kinase. These and associated mechanisms lead to significant lipid lowering and body weight loss. An anti-cancer action has come up in recent years, with mechanisms partly dependent on the mitochondrial activity and also on phosphatidylinositol 3-kinase resistance occurring in some malignant tumors. The potential of metformin to raise life-length is the object of large ongoing studies and of several basic and clinical investigations. The present review article will attempt to investigate the basic mechanisms behind these diverse activities and the potential clinical benefits. Metformin may act on transcriptional activity by histone modification, DNA methylation and miRNAs. An activity on age-associated inflammation (inflammaging) may occur via activation of the nuclear factor erythroid 2 related factor and changes in gut microbiota. A senolytic activity, leading to reduction of cells with the senescent associated secretory phenotype, may be crucial in lifespan prolongation as well as in ancillary properties in age-associated diseases, such as Parkinson's disease. Telomere prolongation may be related to the activity on mitochondrial respiratory factor 1 and on peroxisome gamma proliferator coactivator 1-alpha. Very recent observations on the potential to act on the most severe neurological disorders, such as amyotrophic lateral sclerosis and frontotemporal dementia, have raised considerable hope.

Metformin relieves bone cancer pain by reducing TGFβRI-TRPV1 signaling in rats

Common cancer complications include bone cancer pain (BCP), which was not sufficiently alleviated by traditional analgesics. More safe and effective therapy was urgent needed. Metformin relieved osteoarthritis pain, but the analgesia of Metformin in BCP was not well studied. The study aimed to explore the Metformin-mediated analgesic effect and its molecular mechanisms in BCP rats. We demonstrated that Walker 256 cell transplantation into the medullary cavity of the tibia worsened mechanical allodynia in BCP rats, increased the expression of TGFβ1 in the metastatic bone tissue, and raised the expression of TGFβRI and TRPV1 in the L4-6 dorsal root ganglion (DRG) of BCP rats. While, selectively blockade of TGFβRI by SD208 could obviously elevated the paw withdraw threshold (PWT) of BCP rats, together with decreased TRPV1 expression in L4-6 DRG. Notably, continuous Metformin treatment reduced TGFβ1, TGFβRI and TRPV1 expression, and relieved mechanical allodynia of BCP rats in a long-term effect. In conclusion, these results illustrated that Metformin ameliorated bone cancer pain, and the downregulation of TGFβ1-TGFβRI-TRPV1 might be a potential mechanism of Metformin-mediated analgesia in BCP.

Will AMPK be a potential therapeutic target for hepatocellular carcinoma?

Cancer is the disease that poses the greatest threat to human health today. Among them, hepatocellular carcinoma (HCC) is particularly prominent due to its high recurrence rate and extremely low five-year postoperative survival rate. In addition to surgical treatment, radiotherapy, chemotherapy, and immunotherapy are the main methods for treating HCC. Due to the natural drug resistance of chemoradiotherapy and targeted drugs, satisfactory results have not been achieved in terms of therapeutic efficacy and cost. AMP-Activated Protein Kinase (AMPK) is a serine/threonine protein kinase. It mainly coordinates the metabolism and transformation of energy between cells, which maintaining a balance between energy supply and demand. The processes of cell growth, proliferation, autophagy, and survival all involve various reaction of cells to energy changes. The regulatory role of AMPK in cellular energy metabolism plays an important role in the occurrence, development, treatment, and prognosis of HCC. Here, we reviewed the latest progress on the regulatory role of AMPK in the occurrence and development of HCC. Firstly, the molecular structure and activation mechanism of AMPK were introduced. Secondly, the emerging regulator related to AMPK and tumors were elaborated. Next, the multitasking roles of AMPK in the occurrence and development mechanism of HCC were discussed separately. Finally, the translational implications and the challenges of AMPK-targeted therapies for HCC treatment were elaborated. In summary, these pieces of information suggest that AMPK can serve as a promising specific therapeutic target for the treatment of HCC.

Metformin reduces basal subpopulation and attenuates mammary epithelial cell stemness in FVB/N mice

Metformin shows promise in breast cancer prevention, but its underlying mechanisms remain unclear. This study investigated the impact of metformin on the repopulation dynamics of mammary epithelial cells (MECs) and the signaling pathways in non-tumorigenic FVB/N mice. This study aimed to enhance our understanding of the role of metformin in reducing the susceptibility of MECs in premalignant tissues to oncogenic factors. In this study, female mice were administered 200 mg/kg/day of metformin via intraperitoneal (i.p.) injection from 8 to 18 weeks of age. After this treatment period, morphogenesis, flow cytometry, analyses of MEC stemness, and RNA sequencing were performed. The study findings indicated that metformin treatment in adult mice reduced mammary gland proliferation, as demonstrated by decreased Ki67+ cells and lateral bud formation. Additionally, metformin significantly reduced both basal and mammary repopulating unit subpopulations, indicating an impact on mammary epithelial cell repopulation. Mammosphere, colony-forming cell, and 3D culture assays revealed that metformin adversely affected mammary epithelial cell stemness. Furthermore, metformin downregulated signaling in key pathways including AMPK/mTOR, MAPK/Erk, PI3K/Akt, and ER, which contribute to its inhibitory effects on mammary proliferation and stemness. Transcriptome analysis with RNA sequencing indicated that metformin induced significant downregulation of genes involved in multiple critical pathways. KEGG-based pathway analysis indicated that genes in PI3K/Akt, focal adhesion, ECM-receptor, small cell lung cancer and immune-modulation pathways were among the top groups of differentially regulated genes. In summary, our research demonstrates that metformin inhibits MEC proliferation and stemness, accompanied by the downregulation of intrinsic signaling. These insights suggest that the regulatory effects of metformin on premalignant mammary tissues could potentially delay or prevent the onset of breast cancer, offering a promising avenue for developing new preventive strategies.

Efficacy and safety of immune checkpoint inhibitors in solid tumor patients combined with chronic coronary syndromes or its risk factor: a nationwide multicenter cohort study

BACKGROUND

Although, immune checkpoint inhibitors (ICIs) have been widely applied in the therapy of malignant tumors, the efficacy and safety of ICIs in patients with tumors and pre-existing CAD, especially chronic coronary syndromes (CCS) or their risk factors (CRF), is not well identified.

METHODS

This was a nationwide multicenter observational study that enrolled participants who diagnosed with solid tumors and received ICIs therapy. The main efficacy indicators were progression-free survival (PFS) and overall survival (OS), followed by objective response rate (ORR) and disease control rate (DCR). Safety was assessed by describing treatment-related adverse events (TRAEs) during ICIs therapy evaluated by the Common Terminology Criteria for Adverse Events 5.0 (CTCAE 5.0).

RESULTS

In the current research, we retrospectively analyzed the data of 551 patients diagnosed with solid tumors and received ICIs therapy, and these patients were divided into CCS/CRF group and non-CCS/CRF group. Patients with CCS/CRF had more favorable PFS and OS than patients without CCS/CRF (P < 0.001) and the pre-existing CCS/CRF was a protective factor for survival. The ORR (51.8% vs. 39.1%) and DCR (95.8% vs. 89.2%) were higher in CCS/CRF group than in non-CCS/CRF group (P = 0.003, P = 0.006). In this study, there was no significant difference in treatment-related adverse events (TRAEs), including immune-related adverse events (irAEs), between the two groups.

CONCLUSIONS

We concluded that ICIs appear to have better efficacy in malignant solid tumor patients with pre-existing CCS/CRF and are not accompanied by more serious irAEs.

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.

Nanomaterials modulate tumor-associated macrophages for the treatment of digestive system tumors

The treatment of digestive system tumors presents challenges, particularly in immunotherapy, owing to the advanced immune tolerance of the digestive system. Nanomaterials have emerged as a promising approach for addressing these challenges. They provide targeted drug delivery, enhanced permeability, high bioavailability, and low toxicity. Additionally, nanomaterials target immunosuppressive cells and reshape the tumor immune microenvironment (TIME). Among the various cells in the TIME, tumor-associated macrophages (TAMs) are the most abundant and play a crucial role in tumor progression. Therefore, investigating the modulation of TAMs by nanomaterials for the treatment of digestive system tumors is of great significance. Here, we present a comprehensive review of the utilization of nanomaterials to modulate TAMs for the treatment of gastric cancer, colorectal cancer, hepatocellular carcinoma, and pancreatic cancer. We also investigated the underlying mechanisms by which nanomaterials modulate TAMs to treat tumors in the digestive system. Furthermore, this review summarizes the role of macrophage-derived nanomaterials in the treatment of digestive system tumors. Overall, this research offers valuable insights into the development of nanomaterials tailored for the treatment of digestive system tumors.

Advances in the mechanism of metformin with wide-ranging effects on regulation of the intestinal microbiota

Metformin is of great focus because of its high safety, low side effects, and various effects other than lowering blood sugar, such as anti-inflammation, anti-tumor, and anti-aging. Studies have shown that metformin has a modulating effect on the composition and function of the intestinal microbiota other than acting on the liver. However, the composition of microbiota is complex and varies to some extent between species and individuals, and the experimental design of each study is also different. Multiple factors present a major obstacle to better comprehending the effects of metformin on the gut microbiota. This paper reviews the regulatory effects of metformin on the gut microbiota, such as increasing the abundance of genus Akkermansia, enriching short-chain fatty acids (SCFAs)-producing bacterial genus, and regulating gene expression of certain genera. The intestinal microbiota is a large and vital ecosystem in the human body and is considered to be the equivalent of an "organ" of the human body, which is highly relevant to human health and disease status. There are a lot of evidences that the gut microbiota is responsible for metformin's widespread effects. However, there are only a few systematic studies on this mechanism, and the specific mechanism is still unclear. This paper aims to summarize the possible mechanism of metformin in relation to gut microbiota.

Metabolic dysregulation in obese women and the carcinogenesis of gynecological tumors: A review

Obesity is a significant health issue associated with increased cancer risks, including gynecological malignancies. The worldwide rise in obesity rates is significantly impacting both cancer development and treatment outcomes. Adipose tissue plays a crucial role in metabolism, secreting various substances that can influence cancer formation. In obese individuals, dysfunctional adipose tissue can contribute to cancer development through inflammation, insulin resistance, hormonal changes, and abnormal cholesterol metabolism. Studies have shown a strong correlation between obesity and gynecological cancers, particularly endometrial and breast cancers. Obesity not only increases the risk of developing these cancers but is also associated with poorer outcomes. Additionally, obesity affects the perioperative management of gynecological cancers, requiring specialized care due to increased complications and resistance to therapy. Treatment strategies for managing metabolic dysregulation in patients with gynecological cancers include weight management, statin therapy, and insulin-sensitizing medications. Emerging studies suggest that interventions like intermittent fasting and caloric restriction may enhance the effectiveness of cancer treatments. Furthermore, targeting cholesterol metabolism, such as with statins or proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, shows potential in cancer therapy. In conclusion, addressing metabolic issues, particularly obesity, is crucial in preventing and treating gynecological malignancies. Personalized approaches focusing on weight management and metabolic reprogramming may improve outcomes in these patients.

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.

The troglitazone derivative EP13 disrupts energy metabolism through respiratory chain complex I inhibition in breast cancer cells and potentiates the antiproliferative effect of glycolysis inhibitors

BACKGROUND

The metabolism of cancer cells generally differs from that of normal cells. Indeed, most cancer cells have a high rate of glycolysis, even at normal oxygen concentrations. These metabolic properties can potentially be exploited for therapeutic intervention. In this context, we have developed troglitazone derivatives to treat hormone-sensitive and triple-negative breast cancers, which currently lack therapeutic targets, have an aggressive phenotype, and often have a worse prognosis than other subtypes. Here, we studied the metabolic impact of the EP13 compound, a desulfured derivative of Δ2-troglitazone that we synthetized and is more potent than its parent compounds.

METHODS

EP13 was tested on two triple-negative breast cancer cell lines, MDA-MB-231 and Hs578T, and on the luminal cell line MCF-7. The oxygen consumption rate (OCR) of the treated cell lines, Hs578T mammospheres and isolated mitochondria was measured using the XFe24 Seahorse analyser. ROS production was quantified using the MitoSOX fluorescent probe. Glycolytic activity was evaluated through measurement of the extracellular acidification rate (ECAR), glucose consumption and lactate production in extracellular medium. The synergistic effect of EP13 with glycolysis inhibitors (oxamate and 2-deoxyglucose) on cell cytotoxicity was established using the Chou-Talalay method.

RESULTS

After exposure to EP13, we observed a decrease in the mitochondrial oxygen consumption rate in MCF7, MDA-MB-231 and Hs578T cells. EP13 also modified the maximal OCR of Hs578T spheroids. EP13 reduced the OCR through inhibition of respiratory chain complex I. After 24 h, ATP levels in EP13-treated cells were not altered compared with those in untreated cells, suggesting compensation by glycolysis activity, as shown by the increase in ECAR, the glucose consumption and lactate production. Finally, we performed co-treatments with EP13 and glycolysis inhibitors (oxamate and 2-DG) and observed that EP13 potentiated their cytotoxic effects.

CONCLUSION

This study demonstrates that EP13 inhibits OXPHOS in breast cancer cells and potentiates the effect of glycolysis inhibitors.

Recent developments in targeting breast cancer stem cells (BCSCs): a descriptive review of therapeutic strategies and emerging therapies

Despite recent advancements in the diagnosis and treatment of breast cancer (BC), patient outcomes in terms of survival, recurrence, and disease progression remain suboptimal. A significant factor contributing to these challenges is the cellular heterogeneity within BC, particularly the presence of breast cancer stem cells (BCSCs). These cells are thought to serve as the clonogenic nexus for new tumor growth, owing to their hierarchical organization within the tumor. This descriptive review focuses on the evolving strategies to target BCSCs, which have become a pivotal aspect of therapeutic development. We explore a variety of approaches, including targeting specific tumor surface markers (CD133 and CD44), transporters, heat shock proteins, and critical signaling pathways like Notch, Akt, Hedgehog, KLF4, and Wnt/β-catenin. Additionally, we discuss the modulation of the tumor microenvironment through the CXCR-12/CXCR4 axis, manipulation of pH levels, and targeting hypoxia-inducible factors, vascular endothelial growth factor, and CXCR1/2 receptors. Further, this review focuses on the roles of microRNA expression, strategies to induce apoptosis and differentiation in BCSCs, dietary interventions, dendritic cell vaccination, oncolytic viruses, nanotechnology, immunotherapy, and gene therapy. We particularly focused on studies reporting identification of BCSCs, their unique properties and the efficacy of various therapeutic modalities in targeting these cells. By dissecting these approaches, we aim to provide insights into the complex landscape of BC treatment and the potential pathways for improving patient outcomes through targeted BCSC therapies.

Metformin Loaded Zein Polymeric Nanoparticles to Augment Antitumor Activity against Ehrlich Carcinoma via Activation of AMPK Pathway: D-Optimal Design Optimization, In Vitro Characterization, and In Vivo Study

Metformin (MET), an antidiabetic drug, is emerging as a promising anticancer agent. This study was initiated to investigate the antitumor effects and potential molecular targets of MET in mice bearing solid Ehrlich carcinoma (SEC) as a model of breast cancer (BC) and to explore the potential of zein nanoparticles (ZNs) as a carrier for improving the anticancer effect of MET. ZNs were fabricated through ethanol injection followed by probe sonication method. The optimum ZN formulation (ZN8) was spherical and contained 5 mg zein and 30 mg sodium deoxycholate with a small particle size and high entrapment efficiency percentage and zeta potential. A stability study showed that ZN8 was stable for up to three months. In vitro release profiles proved the sustained effect of ZN8 compared to the MET solution. Treatment of SEC-bearing mice with ZN8 produced a more pronounced anticancer effect which was mediated by upregulation of P53 and miRNA-543 as well as downregulation of NF-κB and miRNA-191-5p gene expression. Furthermore, ZN8 produced a marked elevation in pAMPK and caspase-3 levels as well as a significant decrease in cyclin D1, COX-2, and PGE2 levels. The acquired findings verified the potency of MET-loaded ZNs as a treatment approach for BC.

Identification and validation of DHCR7 as a diagnostic biomarker involved in the proliferation and mitochondrial function of breast cancer

BACKGROUND

Energy metabolism has a complex intersection with pathogenesis and development of breast cancer (BC). This allows for the possibility of identifying energy-metabolism-related genes (EMRGs) as novel prognostic biomarkers for BC. 7-dehydrocholesterol reductase (DHCR7) is a key enzyme of cholesterol biosynthesis involved in many cancers, and in this paper, we investigate the effects of DHCR7 on the proliferation and mitochondrial function of BC.

METHODS

EMRGs were identified from the Gene Expression Omnibus (GEO) and MSigDB databases using bioinformatics methods. Key EMRGs of BC were then identified and validated by functional enrichment analysis, interaction analysis, weighted gene co-expression network analysis (WGCNA), least absolute shrinkage and selection operator (LASSO) regression, Cox analysis, and immune infiltration. Western blot, qRT-PCR, immunohistochemistry (IHC), MTT assay, colony formation assay and flow cytometry assay were then used to analyze DHCR7 expression and its biological effects on BC cells.

RESULTS

We identified 31 EMRGs in BC. These 31 EMRGs and related transcription factors (TFs), miRNAs, and drugs were enriched in glycerophospholipid metabolism, glycoprotein metabolic process, breast cancer, and cell cycle. Crucially, DHCR7 was a key EMRG in BC identified and validated by WGCNA, LASSO regression and receiver operating characteristic (ROC) curve analysis. High DHCR7 expression was significantly associated with tumor immune infiltration level, pathological M, and poor prognosis in BC. In addition, DHCR7 knockdown inhibited cell proliferation, induced apoptosis and affected mitochondrial function in BC cells.

CONCLUSIONS

DHCR7 was found to be a key EMRG up-regulated in BC cells. This study is the first to our knowledge to report that DHCR7 acts as an oncogene in BC, which might become a novel therapeutic target for BC patients.

Metformin and Breast Cancer: Current Findings and Future Perspectives from Preclinical and Clinical Studies

Over the last several decades, a growing body of research has investigated the potential to repurpose the anti-diabetic drug metformin for breast cancer prevention and/or treatment. Observational studies in the early 2000s demonstrated that patients with diabetes taking metformin had decreased cancer risk, providing the first evidence supporting the potential role of metformin as an anti-cancer agent. Despite substantial efforts, two decades later, the exact mechanisms and clinical efficacy of metformin for breast cancer remain ambiguous. Here, we have summarized key findings from studies examining the effect of metformin on breast cancer across the translational spectrum including in vitro, in vivo, and human studies. Importantly, we discuss critical factors that may help explain the significant heterogeneity in study outcomes, highlighting how metformin dose, underlying metabolic health, menopausal status, tumor subtype, membrane transporter expression, diet, and other factors may play a role in modulating metformin's anti-cancer effects. We hope that these insights will help with interpreting data from completed studies, improve the design of future studies, and aid in the identification of patient subsets with breast cancer or at high risk for the disease who are most likely to benefit from metformin treatment.

Targeting and repolarizing M2-like tumor-associated macrophage-mediated MR imaging and tumor immunotherapy by biomimetic nanoparticles

Anti-tumor M1-like and pro-tumor M2-like tumor-associated macrophages (TAMs) coexist in tumor microenvironments (TME). The adverse effects of these M1/M2 subsets on tumors directly affect the current strategies to improve anti-tumor immune response. Therefore, it has attracted great attention to change the tumor immunosuppressive microenvironment by reprogramming TAMs. In this paper, we constructed biomimetic nanoparticles (HMMDN-Met@PM) targeting M2-like TAMs for macrophage re-polarization. In detail, the core of the biomimetic nanoparticles is metformin-loaded hollow mesoporous manganese dioxide nanoparticles (HMMDN-Met). Benefited from the hollow and porous structure of HMMDN, metformin, the regulator of M1/M2 adopted in this work, can be easily and widely loaded into HMMDN. Moreover, macrophage membranes were utilized for HMMDN-Met coating (HMMDN-Met@MM) to prevent the premature drug leakage and provide specific molecular recognition/TME targeting. In addition, M2 macrophage targeting peptide (M2pep) was modified on the surface of macrophage membrane to specifically deliver the drug to M2-like TAMs to promote the polarization of M2 to M1 macrophages. Through in vitro and in vivo studies, we found that the expression of surface markers and inflammatory factors CD206, Arg-1 and IL-10 of type M2 macrophages decreased, while the surface markers of type M1 macrophages and the expression of inflammatory factors CD80, TNF-α and iNOS increased, indicating the successful re-polarization of M2 macrophages and finally realizing the inhibition of tumor growth. At the same time, under the acidic and GSH conditions of tumor, HMMDN was decomposed into Mn2+, which is a contrast agent for magnetic resonance imaging, thus realizing the tracking of tumor. This work practices biomimetic nanosystem in targeted imaging and immunotherapy, paving the way for strategy designing for tumor inhibition.

Niosomal Delivery of Celecoxib and Metformin for Targeted Breast Cancer Treatment

Breast cancer continues to be a prominent worldwide health concern and requires continued investigation into innovative therapeutic approaches. Here, we report the first investigation into the therapeutic efficacy of combining Metformin (MET) and Celecoxib (CXB), both in free and niosomal form, for the treatment of breast cancer. Our investigation encompassed the characterization of these niosomal drug carriers, their stability assessment, and their effect on breast cancer cell models. The thin-film hydration technique was employed to prepare niosomes with spherical, uniform-size distributions and high encapsulation efficiencies. The niosomes were characterized by TEM, particle size analyzer, and ATR-FTIR. The niosomes with an average size of 110.6 ± 0.6 and 96.7 ± 0.7, respectively, for MET and CXB were stable when stored at 4 °C for three months with minimal drug leakage, minor changes in encapsulation efficiency and size, and unchanged physicochemical parameters. Evaluation in two-dimensional (2D) and three-dimensional (3D) viability assays demonstrated an increased cytotoxicity of encapsulated drugs when compared to their free-drug counterparts. Additionally, the combination of Metformin Niosomal Particles (MET NPs) and Celecoxib Niosomal Particles (CXB NPs) led to decreased cell viability in both 2D and 3D models compared to each drug administered individually. When comparing the effect of the niosomal versus the free combination of the drugs on cell migration, we found that both interventions effectively prevented cell migration. However, the efficacy of the niosomes' combination was not superior to that of the free drug combination (p < 0.05). In conclusion, the results of this study provide valuable insights into the potential application of combining MET and CXB nanoparticle delivery systems to breast cancer treatment. Exploring the in vivo application of this drug delivery system could open new avenues for more effective and targeted therapeutic approaches for breast cancer patients.

Metformin as an activator of AMP-activated protein kinase. Known and new mechanisms of action

Metformin, known in the medical community as the drug of first choice for type 2 diabetes mellitus, belongs to the group of biguanides and has proven to be an effective treatment in clinical practice. Our knowledge of the pharmacodynamic properties of metformin has long been limited to the following well-known mechanisms: a decrease in hyperglycemia due to an increase in peripheral insulin sensitivity, glucose utilization by cells, inhibition of hepatic gluconeogenesis, an increase in the capacity of all types of membrane glucose transporters, activation of fibrinolysis, and a decrease in the levels of atherogenic lipoproteins. Recent studies show that the range of positive pleiotropic effects of metformin is not limited to the above, and that the molecular mechanisms of its action are more complex than previously thought. This article presents a less known, but equally important action of metformin, in particular, its anti-oncogenic, antiviral, and anti-aging effects. In our study, we highlight that the activation of 5’-adenosine monophosphate-activated protein kinase (AMPK) should be considered as the primary mechanism of action through which almost all beneficial effects are achieved. In the light of recent scientific advances in metformin pharmacology, together with the pathogenetic uncertainty of the term «biguanide», it seems fair and reasonable to apply a more relevant definition to the drugn, namely «AMPK activator».

Obesity-induced changes in cancer cells and their microenvironment: Mechanisms and therapeutic perspectives to manage dysregulated lipid metabolism

Obesity has been closely related to cancer progression, recurrence, metastasis, and treatment resistance. We aim to review recent progress in the knowledge on the obese macroenvironment and the generated adipose tumor microenvironment (TME) inducing lipid metabolic dysregulation and their influence on carcinogenic processes. Visceral white adipose tissue expansion during obesity exerts systemic or macroenvironmental effects on tumor initiation, growth, and invasion by promoting inflammation, hyperinsulinemia, growth-factor release, and dyslipidemia. The dynamic relationship between cancer and stromal cells of the obese adipose TME is critical for cancer cell survival and proliferation as well. Experimental evidence shows that secreted paracrine signals from cancer cells can induce lipolysis in cancer-associated adipocytes, causing them to release free fatty acids and acquire a fibroblast-like phenotype. Such adipocyte delipidation and phenotypic change is accompanied by an increased secretion of cytokines by cancer-associated adipocytes and tumor-associated macrophages in the TME. Mechanistically, the availability of adipose TME free fatty acids and tumorigenic cytokines concomitant with the activation of angiogenic processes creates an environment that favors a shift in the cancer cells toward an aggressive phenotype associated with increased invasiveness. We conclude that restoring the aberrant metabolic alterations in the host macroenvironment and in adipose TME of obese subjects would be a therapeutic option to prevent cancer development. Several dietary, lipid-based, and oral antidiabetic pharmacological therapies could potentially prevent tumorigenic processes associated with the dysregulated lipid metabolism closely linked to obesity.

Updates on Triple-Negative Breast Cancer in Type 2 Diabetes Mellitus Patients: From Risk Factors to Diagnosis, Biomarkers and Therapy

Triple-negative breast cancer (TNBC) is usually the most malignant and aggressive mammary epithelial tumor characterized by the lack of expression for estrogen receptors and progesterone receptors, and the absence of epidermal growth factor receptor (HER)2 amplification. Corresponding to 15-20% of all breast cancers and well-known by its poor clinical outcome, this negative receptor expression deprives TNBC from targeted therapy and makes its management therapeutically challenging. Type 2 diabetes mellitus (T2DM) is the most common ageing metabolic disorder due to insulin deficiency or resistance resulting in hyperglycemia, hyperinsulinemia, and hyperlipidemia. Due to metabolic and hormonal imbalances, there are many interplays between both chronic disorders leading to increased risk of breast cancer, especially TNBC, diagnosed in T2DM patients. The purpose of this review is to provide up-to-date information related to epidemiology and clinicopathological features, risk factors, diagnosis, biomarkers, and current therapy/clinical trials for TNBC patients with T2DM compared to non-diabetic counterparts. Thus, in-depth investigation of the diabetic complications on TNBC onset, development, and progression and the discovery of biomarkers would improve TNBC management through early diagnosis, tailoring therapy for a better outcome of T2DM patients diagnosed with TNBC.

Metformin: A Review of Potential Mechanism and Therapeutic Utility Beyond Diabetes

Metformin has been designated as one of the most crucial first-line therapeutic agents in the management of type 2 diabetes mellitus. Primarily being an antihyperglycemic agent, metformin also has a plethora of pleiotropic effects on various systems and processes. It acts majorly by activating AMPK (Adenosine Monophosphate-Activated Protein Kinase) in the cells and reducing glucose output from the liver. It also decreases advanced glycation end products and reactive oxygen species production in the endothelium apart from regulating the glucose and lipid metabolism in the cardiomyocytes, hence minimizing the cardiovascular risks. Its anticancer, antiproliferative and apoptosis-inducing effects on malignant cells might prove instrumental in the malignancy of organs like the breast, kidney, brain, ovary, lung, and endometrium. Preclinical studies have also shown some evidence of metformin's neuroprotective role in Parkinson's disease, Alzheimer's disease, multiple sclerosis and Huntington's disease. Metformin exerts its pleiotropic effects through varied pathways of intracellular signalling and exact mechanism in the majority of them remains yet to be clearly defined. This article has extensively reviewed the therapeutic benefits of metformin and the details of its mechanism for a molecule of boon in various conditions like diabetes, prediabetes, obesity, polycystic ovarian disease, metabolic derangement in HIV, various cancers and aging.

Understanding tumour endothelial cell heterogeneity and function from single-cell omics

Anti-angiogenic therapies (AATs) are used to treat different types of cancers. However, their success is limited owing to insufficient efficacy and resistance. Recently, single-cell omics studies of tumour endothelial cells (TECs) have provided new mechanistic insight. Here, we overview the heterogeneity of human TECs of all tumour types studied to date, at the single-cell level. Notably, most human tumour types contain varying numbers but only a small population of angiogenic TECs, the presumed targets of AATs, possibly contributing to the limited efficacy of and resistance to AATs. In general, TECs are heterogeneous within and across all tumour types, but comparing TEC phenotypes across tumours is currently challenging, owing to the lack of a uniform nomenclature for endothelial cells and consistent single-cell analysis protocols, urgently raising the need for a more consistent approach. Nonetheless, across most tumour types, universal TEC markers (ACKR1, PLVAP and IGFBP3) can be identified. Besides angiogenesis, biological processes such as immunomodulation and extracellular matrix organization are among the most commonly predicted enriched signatures of TECs across different tumour types. Although angiogenesis and extracellular matrix targets have been considered for AAT (without the hoped success), the immunomodulatory properties of TECs have not been fully considered as a novel anticancer therapeutic approach. Therefore, we also discuss progress, limitations, solutions and novel targets for AAT development.

Why Metformin Should Not Be Used as an Oxidative Phosphorylation Inhibitor in Cancer Patients

BACKGROUND

Preclinical studies have suggested that metformin exerts antitumor effects on various types of cancers. However, the results of human clinical trials have been inconsistent.

SUMMARY

Metformin is widely considered to be a prime example of a clinically relevant compound that inhibits oxidative phosphorylation (OXPHOS). However, the efficacy of metformin in inhibiting OXPHOS in cancer patients remains uncertain. The available evidence suggests that the plasma concentration of metformin remains within the micromolar range when administered at therapeutic doses. While millimolar concentrations are necessary to inhibit complex I activity in isolated mitochondria, there is no evidence supporting the idea that metformin accumulates within the mitochondria. Metformin exerts a modest effect on the adenosine diphosphate to adenosine triphosphate (ATP) ratio, resulting in AMP-activated protein kinase activation, which promotes ATP-generating catabolic pathways and restores cellular energy balance.

KEY MESSAGES

The value of metformin as an OXPHOS inhibitor for cancer treatment is debatable, and caution should be exercised while using metformin for this purpose.

Drug Repurposing in Oncology: A Systematic Review of Randomized Controlled Clinical Trials

Quality pharmacological treatment can improve survival in many types of cancer. Drug repurposing offers advantages in comparison with traditional drug development procedures, reducing time and risk. This systematic review identified the most recent randomized controlled clinical trials that focus on drug repurposing in oncology. We found that only a few clinical trials were placebo-controlled or standard-of-care-alone-controlled. Metformin has been studied for potential use in various types of cancer, including prostate, lung, and pancreatic cancer. Other studies assessed the possible use of the antiparasitic agent mebendazole in colorectal cancer and of propranolol in multiple myeloma or, when combined with etodolac, in breast cancer. We were able to identify trials that study the potential use of known antineoplastics in other non-oncological conditions, such as imatinib for severe coronavirus disease in 2019 or a study protocol aiming to assess the possible repurposing of leuprolide for Alzheimer's disease. Major limitations of these clinical trials were the small sample size, the high clinical heterogeneity of the participants regarding the stage of the neoplastic disease, and the lack of accounting for multimorbidity and other baseline clinical characteristics. Drug repurposing possibilities in oncology must be carefully examined with well-designed trials, considering factors that could influence prognosis.

Bioinformatics and network biology approach to identifying type 2 diabetes genes and pathways that influence the progression of breast cancer

Breast cancer is the second most prevalent malignancy affecting women. Postmenopausal women breast tumor is one of the top causes of death in women, accounting for 23% of cancer cases. Type 2 diabetes, a worldwide pandemic, has been connected to a heightened risk of several malignancies, although its association with breast cancer is still uncertain. In comparison to non-diabetic women, women with T2DM had a 23% elevated likelihood of developing breast cancer. It is difficult to determine causative or genetic susceptibility that connect T2DM and breast cancer. We created a large-scale network-based quantitative approach employing unbiased methods to discover abnormally amplified genes in both T2DM and breast cancer, to solve these issues. We performed transcriptome analysis to uncover identical genetic biomarkers and pathways to clarify the connection between T2DM and breast cancer patients. In this study, two RNA-seq datasets (GSE103001 and GSE86468) from the Gene Expression Omnibus (GEO) are used to identify mutually differentially expressed genes (DEGs) for breast cancer and T2DM, as well as common pathways and prospective medicines. Firstly, 45 shared genes (30 upregulated and 15 downregulated) between T2D and breast cancer were detected. We employed gene ontology and pathway enrichment to characterize prevalent DEGs' molecular processes and signal transduction pathways and observed that T2DM has certain connections to the progression of breast cancer. Using several computational and statistical approaches, we created a protein-protein interactions (PPI) network and revealed hub genes. These hub genes can be potential biomarkers, which may also lead to new therapeutic strategies for investigated diseases. We conducted TF-gene interactions, gene-microRNA interactions, protein-drug interactions, and gene-disease associations to find potential connections between T2DM and breast cancer pathologies. We assume that the potential drugs that emerged from this study could be useful therapeutic values. Researchers, doctors, biotechnologists, and many others may benefit from this research.

Metformin and HER2-positive breast cancer: Mechanisms and therapeutic implications

Due to the strong association between diabetes and cancer incidents, several anti-diabetic drugs, including metformin, have been examined for their anticancer activity. Metformin is a biguanide antihyperglycemic agent used as a first-line drug for type II diabetes mellitus. It exhibits anticancer activity by impacting different molecular pathways, such as AMP-inducible protein kinase (AMPK)-dependent and AMPK-independent pathways. Additionally, Metformin indirectly inhibits IGF-1R signaling, which is highly activated in breast malignancy. On the other hand, breast cancer is one of the major causes of cancer-related morbidity and mortality worldwide, where the human epidermal growth factor receptor-positive (HER2-positive) subtype is one of the most aggressive ones with a high rate of lymph node metastasis. In this review, we summarize the association between diabetes and human cancer, listing recent evidence of metformin's anticancer activity. A special focus is dedicated to HER2-positive breast cancer with regards to the interaction between HER2 and IGF-1R. Then, we discuss combination therapy strategies of metformin and other anti-diabetic drugs in HER2-positive breast cancer.

Targeting Mitochondria with ClpP Agonists as a Novel Therapeutic Opportunity in Breast Cancer

Breast cancer is the most frequently diagnosed malignancy worldwide and the leading cause of cancer mortality in women. Despite the recent development of new therapeutics including targeted therapies and immunotherapy, triple-negative breast cancer remains an aggressive form of breast cancer, and thus improved treatments are needed. In recent decades, it has become increasingly clear that breast cancers harbor metabolic plasticity that is controlled by mitochondria. A myriad of studies provide evidence that mitochondria are essential to breast cancer progression. Mitochondria in breast cancers are widely reprogrammed to enhance energy production and biosynthesis of macromolecules required for tumor growth. In this review, we will discuss the current understanding of mitochondrial roles in breast cancers and elucidate why mitochondria are a rational therapeutic target. We will then outline the status of the use of mitochondria-targeting drugs in breast cancers, and highlight ClpP agonists as emerging mitochondria-targeting drugs with a unique mechanism of action. We also illustrate possible drug combination strategies and challenges in the future breast cancer clinic.

Metformin and long non-coding RNAs in breast cancer

Breast cancer (BC) is the second most common cancer and cause of death in women. In recent years many studies investigated the association of long non-coding RNAs (lncRNAs), as novel genetic factors, on BC risk, survival, clinical and pathological features. Recent studies also investigated the roles of metformin treatment as the firstline treatment for type 2 diabetes (T2D) played in lncRNAs expression/regulation or BC incidence, outcome, mortality and survival, separately. This comprehensive study aimed to review lncRNAs associated with BC features and identify metformin-regulated lncRNAs and their mechanisms of action on BC or other types of cancers. Finally, metformin affects BC by regulating five BC-associated lncRNAs including GAS5, HOTAIR, MALAT1, and H19, by several molecular mechanisms have been described in this review. In addition, metformin action on other types of cancers by regulating ten lncRNAs including AC006160.1, Loc100506691, lncRNA-AF085935, SNHG7, HULC, UCA1, H19, MALAT1, AFAP1-AS1, AC026904.1 is described.

Linking Physical Activity to Breast Cancer Risk via the Insulin/Insulin-like Growth Factor Signaling System, Part 2: The Effect of Insulin/Insulin-like Growth Factor Signaling on Breast Cancer Risk

Perturbation of the insulin/insulin-like growth factor (IGF) signaling system is often cited as a mechanism driving breast cancer risk. A systematic review identified prospective cohort studies and Mendelian randomization studies that examined the effects of insulin/IGF signaling (IGF, their binding proteins (IGFBP), and markers of insulin resistance] on breast cancer risk. Meta-analyses generated effect estimates; risk of bias was assessed and the Grading of Recommendations Assessment, Development and Evaluation system applied to evaluate the overall quality of the evidence. Four Mendelian randomization and 19 prospective cohort studies met our inclusion criteria. Meta-analysis of cohort studies confirmed that higher IGF-1 increased risk of breast cancer; this finding was supported by the Mendelian randomization studies. IGFBP-3 did not affect breast cancer. Meta analyses for connecting-peptide and fasting insulin showed small risk increases, but confidence intervals were wide and crossed the null. The quality of evidence obtained ranged from 'very low' to 'moderate'. There were insufficient studies to examine other markers of insulin/IGF signaling. These findings do not strongly support the biological plausibility of the second part of the physical activity-insulin/IGF signaling system-breast cancer pathway. Robust conclusions cannot be drawn due to the dearth of high quality studies. See related article by Swain et al., p. 2106.

Cancer and Obesity: An Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) 2022

Background

This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) provides an overview of cancer and increased body fat.

Methods

The scientific information for this CPS is based upon published scientific citations, clinical perspectives of OMA authors, and peer review by the Obesity Medicine Association leadership.

Results

Topics include the increased risk of cancers among patients with obesity, cancer risk factor population-attributable fractions, genetic and epigenetic links between obesity and cancer, adiposopathic and mechanistic processes accounting for increased cancer risk among patients with obesity, the role of oxidative stress, and obesity-related cancers based upon Mendelian randomization and observational studies. Other topics include nutritional and physical activity principles for patients with obesity who either have cancer or are at risk for cancer, and preventive care as it relates to cancer and obesity.

Conclusions

Obesity is the second most common preventable cause of cancer and may be the most common preventable cause of cancer among nonsmokers. This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) on cancer is one of a series of OMA CPSs designed to assist clinicians in the care of patients with the disease of obesity. Patients with obesity are at greater risk of developing certain types of cancers, and treatment of obesity may influence the risk, onset, progression, and recurrence of cancer in patients with obesity.

Metformin-induced downregulation of c-Met is a determinant of sensitivity in MDA-MB-468 breast cancer cells

Metformin, the widely used anti-diabetic drug, is emerging as a promising anti-cancer agent. However, response variation among different tumors remains a significant challenge. Hence, identification of the factors that determine metformin sensitivity is of greatest significance for its clinical implementation. In this study, we showed that MDA-MB-468 cells were most sensitive among the five breast cancer cell lines tested. We found that metformin-induced inhibition of MDA-MB-468 cells was correlated with downregulation of c-Met at both protein and mRNA levels. To understand the functional significance of c-Met downregulation in metformin-mediated tumor inhibition, we established control and c-Met overexpressing sublines of MDA-MB-468 cells (468/C and 468/Met) using lentiviral expression system. We demonstrated that overexpression of c-Met significantly attenuated metformin induced inhibition of MDA-MB-468 cells. Metformin-induced inhibition of ALDH1+ cells, which are enriched with cancer stem cells, was also abrogated in 468/Met cells as compared to 468/C cells. Signal transduction analysis of the paired cell lines indicated that c-Met-induced activation of STAT3 and AKT1, and upregulation of Gab1 are related to c-Met-modulated metformin responsiveness. These findings highlight c-Met as a potential key regulator of metformin-mediated inhibition of proliferation and stemness of breast cancer cells, indicating that c-Met overexpression may be a critical factor contributing to metformin resistance. The data also suggest that combination of metformin with c-Met inhibitors could be a useful strategy to improve metformin-mediated anti-cancer efficacies in breast cancer treatment.

Inflammatory Breast Cancer: The Cytokinome of Post-Mastectomy Wound Fluid Augments Proliferation, Invasion, and Stem Cell Markers

Inflammatory breast cancer (IBC) is an aggressive phenotype with a high recurrence and low survival rate. Approximately 90% of local breast cancer recurrences occur adjacent to the same quadrant as the initial cancer, implying that tumor recurrence may be caused by residual cancer cells and/or quiescent cancer stem cells (CSCs) in the tumor. We hypothesized that wound fluid (WF) collected after modified radical mastectomy (MRM) may activate cancer cells and CSCs, promoting epithelial mesenchymal transition (EMT) and invasion. Therefore, we characterized the cytokinome of WF drained from post-MRM cavities of non-IBC and IBC patients. The WF of IBC patients showed a significantly higher expression of various cytokines than in non-IBC patients. In vitro cell culture models of non-IBC and IBC cell lines were grown in media conditioned with and/without WF for 48 h. Afterwards, we assessed cell viability, the expression of CSCs and EMT-specific genes, and tumor invasion. Genes associated with CSCs properties and EMT markers were regulated in cells seeded in media conditioned by WF. IBC-WF exhibited a greater potential for inducing IBC cell invasion than non-IBC cells. The present study demonstrates the role of the post-surgical tumor cavity in IBC recurrence and metastasis.

Metformin counteracts stimulatory effects induced by insulin in primary breast cancer cells

Background

Metabolic disorders are associated with increased incidence, aggressive phenotype and poor outcome of breast cancer (BC) patients. For instance, hyperinsulinemia is an independent risk factor for BC and the insulin/insulin receptor (IR) axis is involved in BC growth and metastasis. Of note, the anti-diabetic metformin may be considered in comprehensive therapeutic approaches in BC on the basis of its antiproliferative effects obtained in diverse pre-clinical and clinical studies.

Methods

Bioinformatics analysis were performed using the information provided by The Invasive Breast Cancer Cohort of The Cancer Genome Atlas (TCGA) project. The naturally immortalized BC cell line, named BCAHC-1, as well as cancer-associated fibroblasts (CAFs) derived from BC patients were used as model systems. In order to identify further mechanisms that characterize the anticancer action of metformin in BC, we performed gene expression and promoter studies as well as western blotting experiments. Moreover, cell cycle analysis, colony and spheroid formation, actin cytoskeleton reorganization, cell migration and matrigel drops evasion assays were carried out to provide novel insights on the anticancer properties of metformin.

Results

We first assessed that elevated expression and activation of IR correlate with a worse prognostic outcome in estrogen receptor (ER)-positive BC. Thereafter, we established that metformin inhibits the insulin/IR-mediated activation of transduction pathways, gene changes and proliferative responses in BCAHC-1 cells. Then, we found that metformin interferes with the insulin-induced expression of the metastatic gene CXC chemokine receptor 4 (CXCR4), which we found to be associated with poor disease-free survival in BC patients exhibiting high levels of IR. Next, we ascertained that metformin prevents a motile phenotype of BCAHC-1 cells triggered by the paracrine liaison between tumor cells and CAFs upon insulin activated CXCL12/CXCR4 axis.

Conclusions

Our findings provide novel mechanistic insights regarding the anti-proliferative and anti-migratory effects of metformin in both BC cells and important components of the tumor microenvironment like CAFs. Further investigations are warranted to corroborate the anticancer action of metformin on the tumor mass toward the assessment of more comprehensive strategies halting BC progression, in particular in patients exhibiting metabolic disorders and altered insulin/IR functions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03463-y.