Metformin in breast cancer: preclinical and clinical evidence

The effects of metformin and PCL-sorafenib nanoparticle co-treatment on MCF-7 cell culture model of breast cancer

Despite breakthrough therapeutics in breast cancer, it is one of the main causes of mortality among women worldwide. Thus, drug therapies for treating breast cancer have recently been developed by scientists. Metformin and sorafenib are well-known therapeutics in breast cancer. In the present study, we combined sorafenib and PCL-sorafenib with metformin to improve drug absorption and promote therapeutic efficiency. The MCF-7 cells were treated with metformin, sorafenib, or PCL-sorafenib. The growth inhibitory effect of these drugs and cell viability were assessed using MTT and flow cytometry assays, respectively. The expression of targeted genes involved in cell proliferation, signaling, and the cell cycle was measured by real-time PCR. The results showed that MCF-7 cells treated with metformin/sorafenib and PCL-sorafenib/metformin co-treatment contributed to 50% viability compared to the untreated group. Moreover, PI and Annexin V staining tests showed that the cell viability for metformin/sorafenib and PCL-sorafenib/metformin was 38% and 17%, respectively. Furthermore, sorafenib/metformin and PCL-sorafenib/metformin lead to p53 gene expression increase by which they can increase ROS, thereby decreasing GPX4 gene expression. In addition, they affected the expression of BCL2 and BAX genes and altered the cell cycle. Together, the combination of PCL-sorafenib/metformin and sorafenib/metformin increased sorafenib absorption at lower doses and also led to apoptosis and oxidative stress increases in MCF-7 cells.

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.

Shared genetics between breast cancer and predisposing diseases identifies novel breast cancer treatment candidates

Background

Current effective breast cancer treatment options have severe side effects, highlighting a need for new therapies. Drug repurposing can accelerate improvements to care, as FDA-approved drugs have known safety and pharmacological profiles. Some drugs for other conditions, such as metformin, an antidiabetic, have been tested in clinical trials for repurposing for breast cancer. Here, we exploit the genetics of breast cancer and linked predisposing diseases to propose novel drug repurposing. We hypothesize that if a predisposing disease contributes to breast cancer pathology, identifying the pleiotropic genes related to the risk of cancer could prioritize drug targets, among all drugs treating a predisposing disease. We aim to develop a method to not only prioritize drug repurposing, but also to highlight shared etiology explaining repurposing.

Methods

We compile breast cancer's predisposing diseases from literature. For each predisposing disease, we use GWAS summary statistics to identify genes in loci showing genetic correlation with breast cancer. Then, we use a network approach to link these shared genes to canonical pathways, and similarly for all drugs treating the predisposing disease, we link their targets to pathways. In this manner, we are able to prioritize a list of drugs based on each predisposing disease, with each drug linked to a set of implicating pathways. Finally, we evaluate our recommendations against drugs currently under investigation for breast cancer.

Results

We identify 84 loci harboring mutations with positively correlated effects between breast cancer and its predisposing diseases; these contain 194 identified shared genes. Out of the 112 drugs indicated for the predisposing diseases, 76 drugs can be linked to shared genes via pathways (candidate drugs for repurposing). Fifteen out of these candidate drugs are already in advanced clinical trial phases or approved for breast cancer (OR = 9.28, p = 7.99e-03, one-sided Fisher's exact test), highlighting the ability of our approach to identify likely successful candidate drugs for repurposing.

Conclusions

Our novel approach accelerates drug repurposing for breast cancer by leveraging shared genetics with its known risk factors. The result provides 59 novel candidate drugs alongside biological insights supporting each recommendation.

Effects of metformin on cancers in experimental and clinical studies: Focusing on autophagy and AMPK/mTOR signaling pathways

Metformin (MET) is a preferred drug for the treatment of type 2 diabetes mellitus. Recent studies show that apart from its blood glucose-lowering effects, it also inhibits the development of various tumours, by inducing autophagy. Various studies have confirmed the inhibitory effects of MET on cancer cell lines' propagation, migration, and invasion. The objective of the study was to comprehensively review the potential of MET as an anticancer agent, particularly focusing on its ability to induce autophagy and inhibit the development and progression of various tumors. The study aimed to explore the inhibitory effects of MET on cancer cell proliferation, migration, and invasion, and its impact on key signaling pathways such as adenosine monophosphate-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), and PI3K. This review noted that MET exerts its anticancer effects by regulating key signalling pathways such as phosphoinositide 3-kinase (PI3K), LC3-I and LC3-II, Beclin-1, p53, and the autophagy-related gene (ATG), inhibiting the mTOR protein, downregulating the expression of p62/SQSTM1, and blockage of the cell cycle at the G0/G1. Moreover, MET can stimulate autophagy through pathways associated with the 5' AMPK, thereby inhibiting he development and progression of various human cancers, including hepatocellular carcinoma, prostate cancer, pancreatic cancer, osteosarcoma, myeloma, and non-small cell lung cancer. In summary, this detailed review provides a framework for further investigations that may appraise the autophagy-induced anticancer potential of MET and its repurposing for cancer treatment.

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.

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.

An effective treatment approach of liposomally encapsulated metformin in colon cancer

Metformin is a drug that is widely used in the treatment of type-2 diabetes and its anticarcinogenic effect has been detected in many studies since the 2000s. Metformin has a short half-life and poor biocompatibility, which limits the activity of the drug. As a solution to this situation, our study aimed to increase the anticarcinogenic effects and reduce the side effects of metformin in colon cancer by liposomal encapsulation. For this purpose, in our study, liposome production was carried out using the thin film hydration method. The amount of metformin loaded in liposomes was determined by a standard absorbance curve at 237 nm. Size distributions and membrane zeta potentials of the liposomes were evaluated with Malvern Zetasizer ZS90. Transmission electron microscopy was performed by staining the liposomes negatively with uranyl acetate. Cultured HT-29 cells were treated with liposomal metformin or free metformin at concentrations of 0, 10, 20, and 40 mM for 24 and 48 h. At the end of the treatment period, cell viability was evaluated by CellTiter-Glo luminescent cell viability test. The anticarcinogenic effects of liposomal and free metformin on HT-29 cells were compared. As a result, liposome encapsulated metformin treatment for 24 h was more effective on HT-29 cells at 20- and 40-mM concentrations causing significantly greater decrease in the IC-50 dose compared to the free metformin. The result suggests that liposomal encapsulated metformin may offer a promising approach to increase the efficacy of the drug in the treatment of colon cancer.

Paclitaxel-loaded niosomes in combination with metformin: development, characterization and anticancer potentials

Aim: This study aims to assess the efficacy of free and niosomes-loaded paclitaxel combined with the anti-diabetic drug metformin. Methods: Paclitaxel was successfully encapsulated in all niosome formulations, using microfluidic mixing, with a maximum encapsulation efficiency of 11.9%. Results: The half maximal inhibitory concentration (IC50) for free paclitaxel in T47D cells was significantly reduced from 0.2 to 0.048 mg/ml when combined with metformin 40 mg. The IC50 of paclitaxel was significantly reduced when loaded in niosomes to less than 0.06 mg/ml alone or with metformin. Conclusion: Paclitaxel combination (free or loaded into niosomes) with metformin significantly improved the anticancer efficacy of paclitaxel, which can serve as a method to reduce the paclitaxel dose and its associated side effects.

Polymeric Micelle-Based Nanogels as Emerging Drug Delivery Systems in Breast Cancer Treatment: Promises and Challenges

Breast cancer is a pervasive global health issue that disproportionately impacts the female population. Over the past few years, there has been considerable interest in nanotechnology due to its potential utility in creating drug-delivery systems designed to combat this illness. The primary aim of these devices is to enhance the delivery of targeted medications, optimise the specific cells that receive the drugs, tackle treatment resistance in malignant cells, and introduce novel strategies for preventing and controlling diseases. This research aims to examine the methodologies utilised by various carrier nanoparticles in the context of therapeutic interventions for breast cancer. The main objective is to investigate the potential application of novel delivery technologies to attain timely and efficient diagnosis and treatment. Current cancer research predominantly examines diverse drug delivery methodologies for chemotherapeutic agents. These methodologies encompass the development of hydrogels, micelles, exosomes, and similar compounds. This research aims to analyse the attributes, intricacies, notable advancements, and practical applications of the system in clinical settings. Despite the demonstrated efficacy of these methodologies, an apparent discrepancy can be observed between the progress made in developing innovative therapeutic approaches and their widespread implementation in clinical settings. It is critical to establish a robust correlation between these two variables to enhance the effectiveness of medication delivery systems based on nanotechnology in the context of breast cancer treatment.

Liposomal Nano-Based Drug Delivery Systems for Breast Cancer Therapy: Recent Advances and Progresses

Breast cancer is a highly prevalent disease on a global scale, with a 30% incidence rate among women and a 14% mortality rate. Developing countries bear a disproportionate share of the disease burden, while countries with greater technological advancements exhibit a higher incidence. A mere 7% of women under the age of 40 are diagnosed with breast cancer, and the prevalence of this ailment is significantly diminished among those aged 35 and younger. Chemotherapy, radiation therapy, and surgical intervention comprise the treatment protocol. However, the ongoing quest for a definitive cure for breast cancer continues. The propensity for cancer stem cells to metastasize and resistance to treatment constitute their Achilles' heel. The advancement of drug delivery techniques that target cancer cells specifically holds significant promise in terms of facilitating timely detection and effective intervention. Novel approaches to pharmaceutical delivery, including nanostructures and liposomes, may bring about substantial changes in the way breast cancer is managed. These systems offer a multitude of advantages, such as heightened bioavailability, enhanced solubility, targeted tumor destruction, and diminished adverse effects. The application of nano-drug delivery systems to administer anti-breast cancer medications is a significant subject of research. This article delves into the domain of breast cancer, conventional treatment methods, the incorporation of nanotechnology into managerial tactics, and strategic approaches aimed at tackling the disease at its core.

A Randomized, Open-Label, Single-Dose, Crossover Study of the Comparative Bioavailability of EPA and DHA in a Novel Liquid Crystalline Nanoparticle-Based Formulation of ω-3 Acid Ethyl Ester Versus Omacor® Soft Capsule among Healthy Adults

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are well known for their capacity to lower triglyceride levels, but the clinical effectiveness is hindered by limited bioavailability and patient adherence. To address this challenge, we introduce a novel liquid crystalline nanoparticle-based formulation, the innovative medicine and drug delivery (IMD)-Omega soft capsule (cap), designed to optimize the pharmacokinetics (PK) and safety of EPA and DHA. This randomized, open-label, crossover study engages a cohort of 24 healthy adult subjects, utilizing key PK parameters like Cmax, AUC, Tmax, t½, and Ke to conduct a comprehensive evaluation. The trial compares the performance of the IMD-Omega soft cap with the well-established Omacor® soft cap. The IMD-Omega soft cap exhibited an impressive 110% increase in bioavailability for EPA and a remarkable 134% surge for DHA in comparison to the Omacor® soft cap over a span of 72 h. The key success can be attributed to the innovative liquid crystalline nanoparticle design, bolstering the dissolution and permeability of these essential fatty acids. Intriguingly, intra-participant variability for AUC0-72 h and Cmax were calculated at 45.04% and 34.26%, respectively. It is noteworthy that the parameters of Tmax for EPA (≈6.00 h) and DHA (≈5.00 h), t½ for both EPA and DHA ≈ 30-40 h, and Kel around 0.18-0.22 h-1 for EPA and ≈0.008-0.02 h-1 for DHA, displayed comparability between the IMD-Omega and Omacor® formulations. Encouragingly, the IMD-Omega soft cap showed excellent tolerability. The promise of optimized patient compliance and reduced dosages adds further weight to its potential significance.

Combination of metformin and gallic acid induces autophagy and apoptosis in human breast cancer cells

Background and purpose

Breast cancer is the most common type of cancer and one of the major causes of death among women. Many reports propose gallic acid as a candidate for cancer treatment due to its biological and medicinal effects as well as its antioxidant properties. This study aimed to assess the effects of metformin and gallic acid on human breast cancer (MCF-7) and normal (MCF-10) cell lines.

Experimental approach

MCF7 and MCF-10 cells were treated with various concentrations of metformin, gallic acid, and their combination. Cell proliferation, reactive oxygen species (ROS), as well as cell cycle arrest were measured. Autophagy induction was assessed using western blot analysis.

Findings/Results

Metformin and gallic acid did not cause toxicity in normal cells. They had a stronger combined impact on ROS induction. Metformin and Gallic acid resulted in cell cycle arrest in the sub-G1 phase with G1 and S phase arrest, respectively. Increased levels of LC3 and Beclin-1 markers along with decreased P62 markers were observed in cancerous cells, which is consistent with the anticancer properties of metformin and gallic acid.

Conclusion and implications

The effects of metformin and gallic acid on cancerous cells indicate the positive impact of their combination in treating human breast cancer.

Metformin derivatives - Researchers' friends or foes?

Metformin has been used for ages to treat diabetes mellitus due to its safety profile and low cost. However, metformin has variable pharmacokinetics in patients, and due to its poor oral absorption, the therapeutic doses are relatively high, causing unpleasant gastrointestinal adverse effects. Therefore, novel derivatives of metformin have been synthesized during the past decades. Particularly, after the mid-2000 s, when organic cation transporters were identified as the main metformin carriers, metformin derivatives have been under intensive investigation. Nevertheless, due to the biguanide structure, derivatives of metformin have been challenging to synthesize. Moreover, the mechanisms of metformin's action are not fully understood to date, and since it has multifunctional properties, the interests have switched to re-purposing for other diseases. Indeed, metformin derivatives have been demonstrated in many cases to be more effective than metformin itself and have the potential to be used in different diseases, including several types of cancers and neurodegenerative diseases. On the other hand, the pleiotropic nature of metformin and its derivatives can also create challenges. Not all properties are fit for all diseases. In this review, the history of the development of metformin-like compounds is summarized, and insights into their potential for future drug discovery are discussed.

Current Cardioprotective Strategies for the Prevention of Radiation-Induced Cardiotoxicity in Left-Sided Breast Cancer Patients

BACKGROUND

Breast cancer (BC) is the most common malignancy in females, accounting for the majority of cancer-related deaths worldwide. There is well-established understanding about the effective role of radiotherapy (RT) in BC therapeutic strategies, offering a better local-regional control, prolonged survival, and improved quality of life for patients. However, it has been proven that conventional RT modalities, especially in left-sided BC cases, are unable to avoid the administration of high RT doses to the heart, thus resulting in cardiotoxicity and promoting long-term cardiovascular diseases (CVD). Recent radiotherapeutic techniques, characterized by dosimetric dose restrictions, target volume revision/modifications, an increased awareness of risk factors, and consistent follow-ups, have created an advantageous context for a significant decrease inpost-RT CVD incidence.

AIM

This review presents the fundamental role of current cardioprotective strategies in the prevention of cardiotoxic effects in left-BCRT.

MATERIAL AND METHODS

A literature search was conducted up to January 2023 using the Cochrane Central Register of Controlled Trials and PubMed Central databases. Our review refers to new radiotherapeutic techniques carried out on patients after BC surgery. Specifically, a dose evaluation of the heart and left anterior descending coronary artery (LADCA) was pointed out for all the included studies, depending on the implemented RT modality, bed positioning, and internal mammary lymph nodes radiation.

RESULTS

Several studies reporting improved heart sparing with new RT techniques in BC patients were searched. In addition to the RT modality, which definitely determines the feasibility of achieving lower doses for the organs at risk (OARs), better target coverage, dose conformity and homogeneity, and the patient's position, characteristics, and anatomy may also affect the evaluated RT dose to the whole heart and its substructures.

CONCLUSIONS

Modern BC RT techniques seem to enable the administration of lower doses to the OARs without compromising on the target coverage. The analysis of several anatomical parameters and the assessment of cardiac biomarkers potentiate the protective effect of these new irradiation modalities, providing a holistic approach to the radiation-associated risks of cardiac disease for BC patients. Despite technological advances, an inevitable cardiac radiation risk still exists, while adverse cardiac events may be observed even many years after RT. Studies with longer follow-ups are required in order to determine the effectiveness of modern breast RT techniques.

Mitochondrial Transfer as a Novel Therapeutic Approach in Disease Diagnosis and Treatment

Mitochondrial dysfunction is a hallmark of numerous diseases, including neurodegenerative disorders, metabolic disorders, and cancer. Mitochondrial transfer, the transfer of mitochondria from one cell to another, has recently emerged as a potential therapeutic approach for restoring mitochondrial function in diseased cells. In this review, we summarize the current understanding of mitochondrial transfer, including its mechanisms, potential therapeutic applications, and impact on cell death pathways. We also discuss the future directions and challenges in the field of mitochondrial transfer as a novel therapeutic approach in disease diagnosis and treatment.

The role of TSC2 in breast cancer: a literature review

TSC2 is a tumor suppressor gene as well as a disease-causing gene for autosomal dominant disorder tuberous sclerosis complex (TSC). Research has found that some tumor tissues have lower TSC2 expression levels than normal tissues. Furthermore, low expression of TSC2 is associated with poor prognosis in breast cancer. TSC2 acts as a convergence point of a complex network of signaling pathways and receives signals from the PI3K, AMPK, MAPK, and WNT pathways. It also regulates cellular metabolism and autophagy through inhibition of a mechanistic target of rapamycin complex, which are processes relevant to the progression, treatment, and prognosis of breast cancer. In-depth study of TSC2 functions provides significant guidance for clinical applications in breast cancer, including improving the treatment efficacy, overcoming drug resistance, and predicting prognosis. In this review, protein structure and biological functions of TSC2 were described and recent advances in TSC2 research in different molecular subtypes of breast cancer were summarized.

AMPK phosphorylates and stabilises copper transporter 1 to synergise metformin and copper chelator for breast cancer therapy

BACKGROUND

Predominant roles of copper and its transporter, copper transporter 1 (CTR1), in tumorigenesis have been explored recently; however, the upstream regulation of CTR1 and combinational intervention of copper chelators in malignancies remain largely unclear.

METHODS

CRISPR/Cas9-based kinome screening was used to identify the CTR1 upstream kinases. Immunofluorescence assays were utilised to detect CTR1 localisation. In vitro kinase assays and mass spectrometry were performed to detect CTR1 phosphorylation. Ubiquitination assays were performed to validate CTR1 stability. Colony formation, EdU labelling, Annexin V-FITC/PI-based apoptosis assays were carried out to detect the drug effect on cell growth and apoptosis. Xenografted mouse models were employed to investigate drug effects in vivo.

RESULTS

We identify that CTR1 undergoes AMPK-mediated phosphorylation, which enhances CTR1 stabilisation and membrane translocation by affecting Nedd4l interaction, resulting in increased oncogenic roles in breast cancer. Importantly, activation of AMPK with its agonist metformin markedly enhances CTR1 levels, and leads to the combinational usage of AMPK agonists and copper chelators for breast cancer treatment.

CONCLUSIONS

Our findings not only reveal the crosstalk between energy response and copper uptake via AMPK-mediated CTR1 phosphorylation and stability but also highlight the strategy to combat breast cancer by a combination of AMPK agonists and copper chelators.

SIGNIFICANCE

The connection between energy response and copper homoeostasis is linked by AMPK phosphorylating and stabilising CTR1, which provides a promising strategy to combat breast cancer by combining AMPK agonists and copper chelators.

A phase II, open-label, non-randomized, prospective study assessing paclitaxel, carboplatin and metformin in the treatment of advanced stage ovarian carcinoma

OBJECTIVE

The purpose of this study was to assess the efficacy and tolerability of a paclitaxel, carboplatin and metformin regimen in the first-line treatment of advanced-stage ovarian, fallopian tube, and primary peritoneal carcinoma.

METHODS

Eligible subjects underwent surgery and 6 cycles of neoadjuvant or adjuvant dose-dense intravenous paclitaxel (80 mg/m²), carboplatin (area under the curve 5 or 6 on Day 1), and oral metformin (850 mg daily). Study participants who completed their primary therapy and attained a clinically defined complete or partial response (PR) were treated with a planned 12 cycles of paclitaxel (135 mg/m² every 21 days) and metformin (850 mg twice daily) maintenance therapy.

RESULTS

Thirty subjects received a median of 6 cycles (range, 5-6) of primary induction chemotherapy and were eligible for response evaluation; twenty-three patients exhibited a complete response, while 3 study patients obtained a PR (an overall response rate of 86.7%). Grade 3-4 hematological toxicity included neutropenia (43.3%), thrombocytopenia (10%) and anemia (36.7%). There was no incidence of grade 3-4 neuropathy although 15 patients (50%) developed grade ≤2 neurotoxicity. Additionally, we observed grade ≤2 diarrhea in 20 (66.7%) subjects. The median progression-free survival was 21 months (range, 3-52) and overall median survival was 35 months (range, 15-61). The subjects also received an aggregate 103 cycles (median, 12; range, 6-12) of maintenance chemotherapy.

CONCLUSION

The study results suggest that the combination of paclitaxel, carboplatin and metformin is associated with moderate efficacy and a reasonable toxicity profile.

Metformin: new applications for an old drug

Metformin is a biguanide, evolved as one of the most widely used medicines. The applications of this component include but are not limited to reducing blood glucose, weight loss, and polycystic ovary syndrome. Studies about other probable indications have emerged, indicating that this agent can also be utilized for other purposes. In this review, applications of metformin are noticed based on the current evidence. Metformin commonly is used as an off-label drug in non-alcoholic fatty liver disease (NAFLD), but it worsens inflammation and should not be used for this purpose, according to the latest research. Metformin decreased the risk of death in patients with liver cirrhosis. It is an effective agent in the prevention and improvement of survival in patients suffering hepatocellular carcinoma. There is evidence of the beneficial effects of metformin in colorectal cancer, early-stage prostate cancer, breast cancer, urothelial cancer, blood cancer, melanoma, and bone cancer, suggesting metformin as a potent anti-tumor agent. Metformin shows neuroprotective effects and provides a potential therapeutic benefit for mild cognitive impairment and Alzheimer's disease (AD). It also has been shown to improve mental function and reduce the incidence of dementia. Another condition that metformin has been shown to slow the progression of is Duchenne muscular dystrophy. Regarding infectious diseases, tuberculosis (TB) and coronavirus disease (COVID-19) are among the conditions suggested to be affected by metformin. The beneficial effects of metformin in cardiovascular diseases were also reported in the literature. Concerning renal function, studies showed that daily oral administration of metformin could ameliorate kidney fibrosis and normalize kidney structure and function. This study reviewed the clinical and preclinical evidence about the possible benefits of metformin based on recent studies. Numerous questions like whether these probable indications of metformin can be observed in non-diabetics, need to be described by future basic experiments and clinical studies.

Drug repurposing and molecular mechanisms of the antihypertensive drug candesartan as a TMEM16A channel inhibitor

TMEM16A, a Ca²⁺-activated chloride channel (CaCC), and its pharmacological inhibitors can inhibit the growth of lung adenocarcinoma cells. However,the poor efficacy, safety, and stability of TMEM16A inhibitors limit the development of these agents. Therefore, finding new therapeutic directions from already marketed drugs is a feasible strategy to obtain safe and effective therapeutic drugs. Here, we screened a library contain more than 2400 FDA, EMA, and NMPA-approved drugs through virtual screening. We identified a drug candidate, candesartan (CDST), which showed strong inhibitory effect on the TMEM16A in a concentration-dependent manner with an IC₅₀ of 24.40 ± 3.21 μM. In addition, CDST inhibited proliferation, migration and induced apoptosis of LA795 cells targeting TMEM16A, and significantly inhibited lung adenocarcinoma tumor growth in vivo. The molecular mechanism of CDST inhibiting TMEM16A channel indicated it bound to R515/R535/E623/E624 in the drug pocket, thereby blocked the pore. In conclusion, we identified a novel TMEM16A channel inhibitor, CDST, which exhibited excellent inhibitory activity against lung adenocarcinoma. Considering that CDST has been used in clinical treatment of hypertension, it may play an important role in the combined treatment of hypertension and lung adenocarcinoma as a multi-target drug in the future.

WZB117 Decorated Metformin-Carboxymethyl Chitosan Nanoparticles for Targeting Breast Cancer Metabolism

The "Warburg effect" provides a novel method for treating cancer cell metabolism. Overexpression of glucose transporter 1 (GLUT1), activation of AMP-activated protein kinase (AMPK), and downregulation of mammalian target of rapamycin (mTOR) have been identified as biomarkers of abnormal cancer cell metabolism. Metformin (MET) is an effective therapy for breast cancer (BC), but its efficacy is largely reliant on the concentration of glucose at the tumor site. We propose a WZB117 (a GLUT1 inhibitor)-OCMC (O-carboxymethyl-chitosan)-MET combo strategy for simultaneous GLUT1 and mTOR targeting for alteration of BC metabolism. WZB117 conjugated polymeric nanoparticles were 225.67 ± 11.5 nm in size, with a PDI of 0.113 ± 0.16, and an encapsulation of 72.78 6.4%. OCMC pH-dependently and selectively releases MET at the tumor site. MET targets the mTOR pathway in cancer cells, and WZB117 targets BCL2 to alter GLUT1 at the cancer site. WZB117-OCMC-MET overcomes the limitations of MET monotherapy by targeting mTOR and BCL2 synergistically. WZB117-OCMC-MET activates AMPK and suppresses mTOR in a Western blot experiment, indicating growth-inhibitory and apoptotic characteristics. AO/EB and the cell cycle enhance cellular internalization as compared to MET alone. WZB117-OCMC-MET affects cancer cells' metabolism and is a promising BC therapeutic strategy.

Folic Acid Functionalized Diallyl Trisulfide-Solid Lipid Nanoparticles for Targeting Triple Negative Breast Cancer

DATS (diallyl trisulfide), an anti-oxidant and cytotoxic chemical derived from the plant garlic, has been found to have potential therapeutic activity against triple-negative breast cancer (TNBC). Its hydrophobicity, short half-life, lack of target selectivity, and limited bioavailability at the tumor site limit its efficacy in treating TNBC. Overexpression of the Folate receptor on the surface of TNBC is a well-known target receptor for overcoming off-targeting, and lipid nanoparticles solve the limitations of limited bioavailability and short half-life. In order to overcome these constraints, we developed folic acid (FA)-conjugated DATS-SLNs in this research. The design of experiment (DoE) method was employed to optimize the FA-DATS-SLNs' nanoformulation, which resulted in a particle size of 168.2 ± 3.78 nm and a DATS entrapment of 71.91 ± 6.27%. The similarity index between MCF-7 and MDA-MB-231 cell lines demonstrates that FA-DATS-SLNs are more therapeutically efficacious in the treatment of aggravating TNBC. Higher cellular internalization and efficient Bcl2 protein downregulation support the hypothesis that functionalization of the FA on the surface of DATS-SLNs improves anticancer efficacy when compared with DATS and DATS-SLNs. FA-functionalized DATS-SLNs have demonstrated to be a promising therapeutic strategy for TNBC management.

Neoadjuvant docetaxel, epirubicin, and cyclophosphamide with or without metformin in breast cancer patients with metabolic abnormality: results from the randomized Phase II NeoMET trial

PURPOSE

Breast cancer patients with metabolic syndrome (MetS) and its components show worse treatment responses to chemotherapy. Metformin is a widely used antidiabetic drug which also shows potential anticancer effect. This study aims to evaluate the efficacy, safety, and metabolic parameters change of metformin combined with docetaxel, epirubicin, and cyclophosphamide (TEC) in neoadjuvant treatment (NAT) for breast cancer patients with metabolic abnormality.

METHODS

Eligible breast cancer patients were randomized to receive six cycles of TEC (docetaxel 75 mg/m², epirubicin 75 mg/m², and cyclophosphamide 500 mg/m², d1, q3w) or TEC with metformin (TECM, TEC with oral metformin 850 mg once daily for the first cycle, then 850 mg twice daily for the following cycles). The primary end point was total pathological complete response (tpCR, ypTis/0N0) rate.

RESULTS

Ninety-two patients were enrolled and randomized from October 2013 to December 2019: 88 patients were available for response and safety assessment. The tpCR rates were 12.5% (5/40) and 14.6% (7/48) in the TEC and TECM groups, respectively (P = 0.777). There was no difference in Ki67 decrease after NAT between two groups (P = 0.456). Toxicity profile were similar between two groups. No grade 3 or higher diarrhea were recorded. Total cholesterol (TC) and high-density lipoprotein cholesterol worsened after NAT in the TEC arm but remained stable in the TECM arm. The absolute increase of TC and low-density lipoprotein cholesterol (LDL-C) was significantly lower in the TECM group compared with the TEC group. After a median follow-up of 40.8 (4.7-70.8) months, no survival difference was observed between TEC and TECM groups (all P > 0.05).

CONCLUSION

Adding metformin to TEC didn't increase pCR rate and disease outcome in breast cancer patients with metabolic abnormality. However, additional metformin treatment with chemotherapy would prevent TC and LDL-C increase after NAT. Trial Registration ClinicalTrials.gov Identifier: NCT01929811.

Genetic Alterations and Deregulation of Hippo Pathway as a Pathogenetic Mechanism in Bone and Soft Tissue Sarcoma

The Hippo pathway is an evolutionarily conserved modulator of developmental biology with a key role in tissue and organ size regulation under homeostatic conditions. Like other signaling pathways with a significant role in embryonic development, the deregulation of Hippo signaling contributes to oncogenesis. Central to the Hippo pathway is a conserved cascade of adaptor proteins and inhibitory kinases that converge and regulate the activity of the oncoproteins YAP and TAZ, the final transducers of the pathway. Elevated levels and aberrant activation of YAP and TAZ have been described in many cancers. Though most of the studies describe their pervasive activation in epithelial neoplasms, there is increasing evidence pointing out its relevance in mesenchymal malignancies as well. Interestingly, somatic or germline mutations in genes of the Hippo pathway are scarce compared to other signaling pathways that are frequently disrupted in cancer. However, in the case of sarcomas, several examples of genetic alteration of Hippo members, including gene fusions, have been described during the last few years. Here, we review the current knowledge of Hippo pathway implication in sarcoma, describing mechanistic hints recently reported in specific histological entities and how these alterations represent an opportunity for targeted therapy in this heterogeneous group of neoplasm.

The crosstalk within the breast tumor microenvironment in type II diabetes: Implications for cancer disparities

Obesity-driven (type 2) diabetes (T2D), the most common metabolic disorder, both increases the incidence of all molecular subtypes of breast cancer and decreases survival in postmenopausal women. Despite this clear link, T2D and the associated dysfunction of diverse tissues is often not considered during the standard of care practices in oncology and, moreover, is treated as exclusion criteria for many emerging clinical trials. These guidelines have caused the biological mechanisms that associate T2D and breast cancer to be understudied. Recently, it has been illustrated that the breast tumor microenvironment (TME) composition and architecture, specifically the surrounding cellular and extracellular structures, dictate tumor progression and are directly relevant for clinical outcomes. In addition to the epithelial cancer cell fraction, the breast TME is predominantly made up of cancer-associated fibroblasts, adipocytes, and is often infiltrated by immune cells. During T2D, signal transduction among these cell types is aberrant, resulting in a dysfunctional breast TME that communicates with nearby cancer cells to promote oncogenic processes, cancer stem-like cell formation, pro-metastatic behavior and increase the risk of recurrence. As these cells are non-malignant, despite their signaling abnormalities, data concerning their function is never captured in DNA mutational databases, thus we have limited insight into mechanism from publicly available datasets. We suggest that abnormal adipocyte and immune cell exhaustion within the breast TME in patients with obesity and metabolic disease may elicit greater transcriptional plasticity and cellular heterogeneity within the expanding population of malignant epithelial cells, compared to the breast TME of a non-obese, metabolically normal patient. These challenges are particularly relevant to cancer disparities settings where the fraction of patients seen within the breast medical oncology practice also present with co-morbid obesity and metabolic disease. Within this review, we characterize the changes to the breast TME during T2D and raise urgent molecular, cellular and translational questions that warrant further study, considering the growing prevalence of T2D worldwide.

Implications of cancer stem cells in diabetes and pancreatic cancer

This review provides a detailed study of pancreatic cancer (PC) and the implication of different types of cancers concerning diabetes. The combination of anti-diabetic drugs with other anti-cancer drugs and phytochemicals can help prevent and treat this disease. PC cancer stem cells (CSCs) and how they migrate and develop into malignant tumors are discussed. A detailed explanation of the different mechanisms of diabetes development, which can enhance the pancreatic CSCs' proliferation by increasing the IGF factor levels, epigenetic modifications, DNA damage, and the influence of lifestyle factors like obesity, and inflammation, has been discussed. It also explains how cancer due to diabetes is associated with high mortality rates. One of the well-known diabetic drugs, metformin, can be combined with other anti-cancer drugs and prevent the development of PC and has been taken as one of the prime focus in this review. Overall, this paper provides insight into the relationship between diabetes and PC and the methods that can be employed to diagnose this disease at an earlier stage successfully.

Targeting Adiponectin in Breast Cancer

Obesity and breast cancer are two major health issues that could be categorized as sincere threats to human health. In the last few decades, the relationship between obesity and cancer has been well established and extensively investigated. There is strong evidence that overweight and obesity increase the risk of postmenopausal breast cancer, and adipokines are the central players in this relationship. Produced and secreted predominantly by white adipose tissue, adiponectin is a bioactive molecule that exhibits numerous protective effects and is considered the guardian angel of adipokine. In the obesity-cancer relationship, more and more evidence shows that adiponectin may prevent and protect individuals from developing breast cancer. Recently, several updates have been published on the implication of adiponectin in regulating tumor development, progression, and metastases. In this review, we provide an updated overview of the metabolic signaling linking adiponectin and breast cancer in all its stages. On the other hand, we critically summarize all the available promising candidates that may reactivate these pathways mainly by targeting adiponectin receptors. These molecules could be synthetic small molecules or plant-based proteins. Interestingly, the advances in genomics have made it possible to create peptide sequences that could specifically replace human adiponectin, activate its receptor, and mimic its function. Thus, the obvious anti-cancer activity of adiponectin on breast cancer should be better exploited, and adiponectin must be regarded as a serious biomarker that should be targeted in order to confront this threatening disease.

Disrupting metformin adaptation of liver cancer cells by targeting the TOMM34/ATP5B axis

Metformin, a well-known antidiabetic drug, has been repurposed for cancer treatment; however, recently observed drug resistance and tumor metastasis have questioned its further application. Here, we found that long-term metformin exposure led to metabolic adaptation of hepatocellular carcinoma (HCC) cells, which was characterized by an obvious epithelial-mesenchymal transition (EMT) phenotype and compensatory elevation of oxidative phosphorylation (OXPHOS). TOMM34, a translocase of the outer mitochondrial membrane, was upregulated to promote tumor metastasis in response to metformin-induced metabolic stress. Mechanistically, TOMM34 interacted with ATP5B to preserve F₁ F_O -ATPase activity, which conferred mitochondrial OXPHOS and ATP production. This metabolic preference for OXPHOS suggested a large requirement of energy supply by cancer cells to survive and spread in response to therapeutic stress. Notably, disturbing the interaction between TOMM34 and ATP5B using Gboxin, a specific OXPHOS inhibitor, increased sensitivity to metformin and suppressed tumor progression both in vitro and in vivo. Overall, this study demonstrates a molecular link of the TOMM34/ATP5B-ATP synthesis axis during metformin adaptation and provides promising therapeutic targets for metformin sensitization in cancer treatment.

Efficacy of Metformin as Adjuvant Therapy in Metastatic Breast Cancer Treatment

Background: Metformin has been reported to have an anti-tumorigenic impact against metastatic breast cancer (MBC) cells through several mechanisms. Its effect can be evaluated by using many variables such as the response rate (RR) as well as the progression-free survival (PFS). Materials and methods: A prospective study was conducted to investigate and estimate the metformin effect on MBC. About 107 subjects were included in the study and were divided into two groups: Group A included non-diabetic MBC patients treated with metformin in conjunction with chemotherapy and group B included those treated with chemotherapy alone. Both PFS and RR were used as a criteria to evaluate the treatment outcome. Associated adverse effects of metformin were also assessed. Results: The average age of the participants in group A and group B was 50 vs. 47.5, respectively. No significant differences were detected between both cohorts concerning RR levels (regression disease (RD) 27.8% vs. 12.5%, stationary disease (SD) 44.4% vs. 41.7%, progression disease (PD) 27.8% vs. 45.8%, respectively, p = 0.074). Moreover, PFS showed no significant difference between both groups (p = 0.753). There was no significant correlation between metformin concentration and their adverse effects on the study participants. Conclusion: Metformin as an adjuvant therapy to MBC undergoing chemotherapy showed no significant survival benefit as determined by RR and PFS.

NIR-light-controlled G-quadruplex hydrogel for synergistically enhancing photodynamic therapy via sustained delivery of metformin and catalase-like activity in breast cancer

Severely hypoxic condition of tumour represents a notable obstacle against the efficiency of photodynamic therapy (PDT). While mitochondria targeted therapy by metformin has been considered as a promising strategy for reducing oxygen consumption in tumours, its low treatment sensitivity, short half-life and narrow absorption window in vivo remain the intractable challenges. In this report, 5′-guanosine monophosphate (5′GMP), indocyanine green (ICG), hemin and metformin, were combined to construct a smart G-quadruplex (G4) hydrogel named HMI@GEL for breast cancer (BC) treatment. Benefiting from the photothermal (PTT) effect of ICG, HMI@GEL exhibited excellent characteristics of NIR-light-triggered and persistent drug delivery to maintain high intratumoral concentration of metformin. Furthermore, drug loading concentration of metformin reached an amazing 300 ​mg ​mL⁻¹ in HMI@GEL. To our knowledge, it might be the highest loading efficiency in the reported literatures. With the combination of catalase-mimicking Hemin@mil88, metformin could inhibit tumour mitochondrial respiratory significantly, which sequentially permitted in situ efficient oxygen generation. Remarkable apoptosis and necrosis were achieved by the combination of PTT and synergistically enhanced PDT as well as the activated tumour immunotherapy. Collectively, the HMI@GEL in situ injectable platform showed a promising strategy for enhanced PDT by metformin, and opened new perspectives for treating BC versatilely.

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A NIR-light-controlled G-quadruplex hydrogel HMI@GEL loading metformin was prepared for precision breast cancer therapy.

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The extremely high drug loading capacity (300 ​mg ​mL⁻¹) and persistent delivery of metformin was realized for the first time.

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The combination of catalase-mimicking Hemin@mil88 and metformin dual enhanced intracellular ROS generation.

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The tumour immune microenvironment was dramatically reshaped by synthetic photodynamic/photothermal therapy.

Metformin: Is it a drug for all reasons and diseases?

Metformin was first used to treat type 2 diabetes in the late 1950s and in 2022 remains the first-choice drug used daily by approximately 150 million people. An accumulation of positive pre-clinical and clinical data has stimulated interest in re-purposing metformin to treat a variety of diseases including COVID-19. In polycystic ovary syndrome metformin improves insulin sensitivity. In type 1 diabetes metformin may help reduce the insulin dose. Meta-analysis and data from pre-clinical and clinical studies link metformin to a reduction in the incidence of cancer. Clinical trials, including MILES (Metformin In Longevity Study), and TAME (Targeting Aging with Metformin), have been designed to determine if metformin can offset aging and extend lifespan. Pre-clinical and clinical data suggest that metformin, via suppression of pro-inflammatory pathways, protection of mitochondria and vascular function, and direct actions on neuronal stem cells, may protect against neurodegenerative diseases. Metformin has also been studied for its anti-bacterial, -viral, -malaria efficacy. Collectively, these data raise the question: Is metformin a drug for all diseases? It remains unclear as to whether all of these putative beneficial effects are secondary to its actions as an anti-hyperglycemic and insulin-sensitizing drug, or result from other cellular actions, including inhibition of mTOR (mammalian target for rapamycin), or direct anti-viral actions. Clarification is also sought as to whether data from ex vivo studies based on the use of high concentrations of metformin can be translated into clinical benefits, or whether they reflect a 'Paracelsus' effect. The environmental impact of metformin, a drug with no known metabolites, is another emerging issue that has been linked to endocrine disruption in fish, and extensive use in T2D has also raised concerns over effects on human reproduction. The objectives for this review are to: 1) evaluate the putative mechanism(s) of action of metformin; 2) analyze the controversial evidence for metformin's effectiveness in the treatment of diseases other than type 2 diabetes; 3) assess the reproducibility of the data, and finally 4) reach an informed conclusion as to whether metformin is a drug for all diseases and reasons. We conclude that the primary clinical benefits of metformin result from its insulin-sensitizing and antihyperglycaemic effects that secondarily contribute to a reduced risk of a number of diseases and thereby enhancing healthspan. However, benefits like improving vascular endothelial function that are independent of effects on glucose homeostasis add to metformin's therapeutic actions.

Anticancer effects of metformin in experimental animal models of different types of cancer: a systematic review and meta-analysis

To systematically evaluate the effects of metformin on tumors in experimental animal models of different types of cancer. Pubmed, Embase, Cochrane, and Web of Science databases were searched for studies on metformin used in various experimental animal tumor models from 2008 to 2022. Meta-analysis was performed using STATA 16.0 software after screening literature extraction data and methodological quality evaluation by inclusion and exclusion criteria. A total of 24 studies with 1108 model animals were included. Meta-analysis results showed that this study used meta-analysis for quantitative synthesis of study results and found that tumor model animals of different species showed different degrees of reduction in tumor volume, weight, and number after metformin intervention.

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.

Association Between Metformin Use and the Risk, Prognosis of Gynecologic Cancer

Background

For gynecological cancer patients, the beneficial effect of metformin use remains controversial due to inconsistent results of published articles. By conducting a meta-analysis, we aimed to evaluate the effect of metformin in reducing the risk and improving the survival of gynecological cancer among women with diabetes mellitus (DM).

Methods

Articles exploring association between metformin use and the risk, as well as prognosis of gynecologic cancer in DM, were searched in the databases: PubMed, Web of Science, SCOPUS, EMBASE, EBSCO, and PROQUEST. Articles were published before May 2022. All the studies were conducted using STATA 12.0 software.

Results

The meta-analysis showed no significant association between metformin use and risk of gynecologic cancer in DM with a random effects model [odds ratio (ORs)/relative risk (RR) = 0.91, 95% confidence intervals (CI) 0.77 to 1.08, I² = 84.2%, p < 0.001]. Metformin use was associated with reduced overall survival (OS) and progression-free survival (PFS) of gynecologic cancer in DM with random effects models [OS: hazard ratio (HR) = 0.60, 95% CI 0.49–0.74, I² = 55.2%, p = 0.002; PFS: HR = 0.55, 95% CI 0.33–0.91, I² = 69.1%, p = 0.006], whereas no significant association was showed between metformin use and recurrence-free survival (RFS), as well as cancer-specific survival (CSS) of gynecologic cancer in DM with random effects models (RFS: HR = 0.60, 95% CI 0.30–1.18, I² = 73.7%, p = 0.010; CSS: HR = 0.78, 95% CI 0.43–1.41, I² = 72.4%, p = 0.013).

Conclusions

In conclusion, this meta-analysis indicated that metformin may be a useful adjuvant agent for gynecological cancer with DM, especially for patients with ovarian cancer and endometrial cancer.

Targeting mitochondrial metabolism for precision medicine in cancer

During decades, the research field of cancer metabolism was based on the Warburg effect, described almost one century ago. Lately, the key role of mitochondria in cancer development has been demonstrated. Many mitochondrial pathways including oxidative phosphorylation, fatty acid, glutamine, and one carbon metabolism are altered in tumors, due to mutations in oncogenes and tumor suppressor genes, as well as in metabolic enzymes. This results in metabolic reprogramming that sustains rapid cell proliferation and can lead to an increase in reactive oxygen species used by cancer cells to maintain pro-tumorigenic signaling pathways while avoiding cellular death. The knowledge acquired on the importance of mitochondrial cancer metabolism is now being translated into clinical practice. Detailed genomic, transcriptomic, and metabolomic analysis of tumors are necessary to develop more precise treatments. The successful use of drugs targeting metabolic mitochondrial enzymes has highlighted the potential for their use in precision medicine and many therapeutic candidates are in clinical trials. However, development of efficient personalized drugs has proved challenging and the combination with other strategies such as chemocytotoxic drugs, immunotherapy, and ketogenic or calorie restriction diets is likely necessary to boost their potential. In this review, we summarize the main mitochondrial features, metabolic pathways, and their alterations in different cancer types. We also present an overview of current inhibitors, highlight enzymes that are attractive targets, and discuss challenges with translation of these approaches into clinical practice. The role of mitochondria in cancer is indisputable and presents several attractive targets for both tailored and personalized cancer therapy.

The impact of metformin use on the outcomes of locally advanced breast cancer patients receiving neoadjuvant chemotherapy: an open-labelled randomized controlled trial

Recently, several clinical trials have attempted to find evidence that supports the anticancer use of metformin in breast cancer (BC) patients. The current study evaluates the anticancer activity of metformin in addition to neoadjuvant chemotherapy (NACT) in locally advanced BC patients. Additionally, we assess the safety and tolerability of this combination and its effect on the quality of life (QoL) of BC patients. Eighty non-diabetic female patients with proven locally advanced BC were randomized into two arms. The first arm received anthracycline/taxane-based NACT plus metformin. The second arm received anthracycline/taxane-based NACT only. Overall response rate (ORR), clinical complete response (cCr), pathological complete response (pCR), and breast conservative rate (BCR) were evaluated between both groups, and correlated with serum metformin concentration. ORR, cCr, pCR, and BCR increased non-significantly in the metformin group compared to the control group; 80.6% vs 68.4%, 27.8% vs 10.5%, 22.2% vs 10.5%, and 19.4% vs 13.2%, respectively. A trend towards cCR and pCR was associated with higher serum metformin concentrations. Metformin decreased the incidence of peripheral neuropathy, bone pain, and arthralgia, although worsened the gastrointestinal adverse events. Metformin combination with NACT has no effect on the QoL of BC patients. Metformin combination with NACT is safe, tolerable, and improves non-significantly the clinical and pathological tumor response of BC patients.

Effects of melatonin and metformin in preventing lysosome-induced autophagy and oxidative stress in rat models of carcinogenesis and the impact of high-fat diet

Imbalanced glucose tolerance and insulin resistance remain important as high cancer risk factors. Metformin administration to diabetic patients may be associated with a reduced risk of malignancy. The combined effects of the hormone melatonin and metformin in oncology practice have shown positive results. The relevance of our study is to find out the role of specific biomarkers of lysosome destruction and oxidative stress data in carcinogenesis models. The present study was designed to investigate the comparative synergic effect of peroral antidiabetic metformin (MF) and pineal hormone melatonin (MEL) administered alone and in combination in two different rat’s models of mammary tumour proliferation in vivo (N-methyl-N-nitrosourea, NMU or 7,12-dimethylbenz[a]anthracene, DMBA). We have studied the processes of lysosomal destruction (alanyl aminopeptidase AAP, leucyl aminopeptidase LAP, acid phosphatase AcP, β-N-acetylglucosaminidase NAG, β-galactosidase β-GD and β-glucuronidase β-GR) caused by evaluated oxidative stress in three types of tissues (liver, heart, and spleen) in female Sprague–Dawley rats fed a high-fat diet (10% of total fat: 2.5% from lard and 7.5% from palm olein). Our results revealed an increase in the activity of the studied lysosomal enzymes and their expression in a tissue-specific manner depending on the type of chemical agent (NMU or DMBA). MANOVA tests in our study confirmed the influence of the three main factors, type of tissue, chemical impact, and chemopreventive agents, and the combinations of these factors on the lysosomal activity induced during the process of cancerogenesis. The development and induction of the carcinogenesis process in the different rat models with the high-fat diet impact were also accompanied by initiation of free-radical oxidation processes, which we studied at the initial (estimated by the level of diene conjugates) and final (TBARS products) stages of this process. The combined effects of MEL and MF for the two models of carcinogenesis at high-fat diet impact for AAP, LAP, and AcP showed a significant synergistic effect when they impact together when compared with the effects of one substance alone (either MEL or MF) in the breast cancer model experiments. Synergistic effects of limiting destructive processes of lysosomal functioning β-GD enzyme activity we obtained in experiments with MEL and MF chemoprevention for both models of carcinogenesis for three tissues. The statistical SS test allowed us to draw the following conclusions on the role of each lysosomal parameter analyzed as an integral model: NAG > AcP > β-GD > β-GR > AAP > LAP.

Microarray analysis of breast cancer gene expression profiling in response to 2-deoxyglucose, metformin, and glucose starvation

BACKGROUND

Breast cancer (BC) is the most frequently diagnosed cancer in women. Altering glucose metabolism and its effects on cancer progression and treatment resistance is an emerging interest in BC research. For instance, combining chemotherapy with glucose-lowering drugs (2-deoxyglucose (2-DG), metformin (MET)) or glucose starvation (GS) has shown better outcomes than with chemotherapy alone. However, the genes and molecular mechanisms that govern the action of these glucose deprivation conditions have not been fully elucidated. Here, we investigated the differentially expressed genes in MCF-7 and MDA-MB-231 BC cell lines upon treatment with glucose-lowering drugs (2-DG, MET) and GS using microarray analysis to study the difference in biological functions between the glucose challenges and their effect on the vulnerability of BC cells.

METHODS

MDA-MB-231 and MCF-7 cells were treated with 20 mM MET or 4 mM 2-DG for 48 h. GS was performed by gradually decreasing the glucose concentration in the culture medium to 0 g/L, in which the cells remained with fetal bovine serum for one week. Expression profiling was carried out using Affymetrix Human Clariom S microarrays. Differentially expressed genes were obtained from the Transcriptome Analysis Console and enriched using DAVID and R packages.

RESULTS

Our results showed that MDA-MB-231 cells were more responsive to glucose deprivation than MCF-7 cells. Endoplasmic reticulum stress response and cell cycle inhibition were detected after all three glucose deprivations in MDA-MB-231 cells and only under the metformin and GS conditions in MCF-7 cells. Induction of apoptosis and inhibition of DNA replication were observed with all three treatments in MDA-MB-231 cells and metformin-treated MCF-7 cells. Upregulation of cellular response to reactive oxygen species and inhibition of DNA repair mechanisms resulted after metformin and GS administration in MDA-MB-231 cell lines and metformin-treated MCF-7 cells. Autophagy was induced after 2-DG treatment in MDA-MB-231 cells and after metformin in MCF-7 cells. Finally, inhibition of DNA methylation were observed only with GS in MDA-MB-231 cells.

CONCLUSION

The procedure used to process cancer cells and analyze their expression data distinguishes our study from others. GS had the greatest effect on breast cancer cells compared to 2-DG and MET. Combining MET and GS could restrain both cell lines, making them more vulnerable to conventional chemotherapy.

Nicotinamide (niacin) supplement increases lipid metabolism and ROS‐induced energy disruption in triple‐negative breast cancer: potential for drug repositioning as an anti‐tumor agent

Metabolic dysregulation is an important hallmark of cancer. Nicotinamide (NAM), a water‐soluble amide form of niacin (vitamin B3), is currently available as a supplement for maintaining general physiologic functions. NAM is a crucial regulator of mitochondrial metabolism and redox reactions. In this study, we aimed to identify the mechanistic link between NAM‐induced metabolic regulation and the therapeutic efficacy of NAM in triple‐negative breast cancer (TNBC). The combined analysis using multiomics systems biology showed that NAM decreased mitochondrial membrane potential and ATP production, but increased the activities of reverse electron transport (RET), fatty acid β‐oxidation and glycerophospholipid/sphingolipid metabolic pathways in TNBC, collectively leading to an increase in the levels of reactive oxygen species (ROS). The increased ROS levels triggered apoptosis and suppressed tumour growth and metastasis of TNBC in both human organoids and xenograft mouse models. Our results showed that NAM treatment leads to cancer cell death in TNBC via mitochondrial dysfunction and activation of ROS by bifurcating metabolic pathways (RET and lipid metabolism); this provides insights into the repositioning of NAM supplement as a next‐generation anti‐metabolic agent for TNBC treatment.

Metformin and Breast Cancer: Where Are We Now?

Breast cancer is the most prevalent cancer and the leading cause of cancer-related death among women worldwide. Type 2 diabetes–associated metabolic traits such as hyperglycemia, hyperinsulinemia, inflammation, oxidative stress, and obesity are well-known risk factors for breast cancer. The insulin sensitizer metformin, one of the most prescribed oral antidiabetic drugs, has been suggested to function as an antitumoral agent, based on epidemiological and retrospective clinical data as well as preclinical studies showing an antiproliferative effect in cultured breast cancer cells and animal models. These benefits provided a strong rationale to study the effects of metformin in routine clinical care of breast cancer patients. However, the initial enthusiasm was tempered after disappointing results in randomized controlled trials, particularly in the metastatic setting. Here, we revisit the current state of the art of metformin mechanisms of action, critically review past and current metformin-based clinical trials, and briefly discuss future perspectives on how to incorporate metformin into the oncologist’s armamentarium for the prevention and treatment of breast cancer.

Effects of metformin on human bone-derived mesenchymal stromal cell-breast cancer cell line interactions

Metformin is used to treat patients with type 2 diabetes mellitus and was found to lower the incidence of cancer. Bone metastasis is a common impairment associated with advanced breast cancer. The present study investigated the effects of metformin on human bone-derived mesenchymal stromal cells (BM-MSC)—breast cancer cell line interactions. BM-MSCs grown from box chisels were tested for growth-stimulating and migration-controlling activity on four breast cancer cell lines either untreated or after pretreatment with metformin. Growth stimulation was tested in MTT tests and migration in scratch assays. Furthermore, the expression of adipokines of BM-MSCs in response to metformin was assessed using Western blot arrays. Compared to breast cancer cell lines (3.6 ± 1.4% reduction of proliferation), 500 µM metformin significantly inhibited the proliferation of BM-MSC lines (mean 12.3 ± 2.2 reduction). Pretreatment of BM-MSCs with metformin showed variable effects of the resulting conditioned media (CM) on breast cancer cell lines depending on the specific BM-MSC—cancer line combination. Metformin significantly reduced the migration of breast cancer cell lines MDA-MB-231 and MDA-MB-436 in response to CM of drug-pretreated BM-MSCs. Assessment of metformin-induced alterations in the expression of adipokines by BM-MSC CM indicated increased osteogenic signaling and possibly impairment of metastasis. In conclusion, the anticancer activities of metformin are the result of a range of direct and indirect mechanisms that lower tumor proliferation and progression. A lower metformin-induced protumor activity of BM-MSCs in the bone microenvironment seem to contribute to the positive effects of the drug in selected breast cancer patients.

Nimbolide, a Neem Limonoid, Inhibits Angiogenesis in Breast Cancer by Abrogating Aldose Reductase Mediated IGF-1/PI3K/Akt Signaling

Background & Objectives:

There is growing evidence to implicate the insulin/IGF-1R/PI3K/Akt signaling cascade in breast cancer development and the central role of aldose reductase (AR) in mediating the crosstalk between this pathway and angiogenesis. The current study was designed to investigate whether nimbolide, a neem limonoid, targets this oncogenic signaling network to prevent angiogenesis in breast cancer.

Methods:

Breast cancer cells (MCF-7, MDA-MB-231), EAhy926 endothelial cells, MDA-MB-231 xenografted nude mice, and tumour tissues from breast cancer patients were used for the study. Expression of AR and key players in IGF-1/PI3K/Akt signaling and angiogenesis was evaluated by qRT-PCR, immunoblotting, and immunohistochemistry. Molecular docking and simulation, overexpression, and knockdown experiments were performed to determine whether nimbolide targets AR and IGF-1R

Results:

Nimbolide inhibited AR with consequent blockade of the IGF-1/PI3K/Akt and HIF-1/VEGF signaling circuit by influencing the phosphorylation and intracellular localisation of key signaling molecules. Downregulation of DNMT-1, HDAC-6, miR-21, HOTAIR, and H19 with upregulation of miR-148a/miR-152 indicated that nimbolide regulates AR and IGF-1/PI3K/Akt signaling via epigenetic modifications. Coadministration of nimbolide with metformin and the chemotherapeutic drugs tamoxifen/cisplatin displayed higher efficacy than single agents in inhibiting IGF-1/PI3K/Akt/AR signaling. Grade-wise increases in IGF-1R and AR expression in breast cancer tissues underscore their value as biomarkers of progression.

Conclusions:

This study provides evidence for the anticancer effects of nimbolide in cellular and mouse models of breast cancer besides providing leads for new drug combinations. It has also opened up avenues for investigating potential molecules such as AR for therapeutic targeting of cancer.

Calorie Restriction for Cancer Prevention and Therapy: Mechanisms, Expectations, and Efficacy

Cancer is one of the most frequently diagnosed diseases, and despite the continuous efforts in searching for new and more effective treatments, its morbidity and mortality remain a significant health problem worldwide. Calorie restriction, a dietary manipulation that consists in a reduction of the calorie intake, is gaining attention as a potential adjuvant intervention for preventing and/or fighting cancer. Several forms of energy reduction intake, which includes caloric restriction tout-court, dietary restrictions, and intermittent fasting, are being explored for their ability to prevent or slow down cancer progression. Additionally, another anti-cancer approach being under investigation relies on the use of nutraceuticals known as “Caloric Restriction Mimetics” that can provide caloric restriction-mediated benefits without subjecting the patients to a strict diet. Preclinical in vitro and in vivo studies consistently show that diet modifiers reducing the calorie have impact on tumor microenvironment and cancer metabolism, resulting in reduced growth and progression of cancer. Preliminary clinical studies show that patients subjected to a reduced nutrient/energy intake experience improved outcomes from chemo- and radiotherapy while better tolerating the side effects. Here, we review the state of the art on the therapeutic potential of calorie restriction and of caloric restriction mimetics in preventing or retarding tumor development by modulating a subset of cellular processes. The most recent clinical progresses with caloric restriction mimetics in the clinical practice are also discussed.

N6-methyladenosine (m6A)-mediated lncRNA DLGAP1-AS1enhances breast canceradriamycin resistance through miR-299-3p/WTAP feedback loop

Chemotherapy resistance is identified as an obstacle for breast cancer (BC) therapy, and, besides, increasing evidence indicates that long-noncoding RNAs (lncRNAs) participate in the regulation of BC adriamycin (ADR) resistance. Here, our work shows that lncRNA DLGAP1 antisense RNA 1 (DLGAP1-AS1) is up-regulated in ADR-resistant BC cells (MCF-7/ADR). Clinically, higher DLGAP1-AS1 expression was closely correlated to poorer clinical prognosis. Results showed that DLGAP1-AS1 promoted the ADR IC50 and proliferation of ADR-resistant cells. Moreover, N6-methyladenosine (m6A) methyltransferase WT1 associated protein (WTAP) binds to the m6A modified site of DLGAP1-AS1 and motivates its stability. Mechanistically, DLGAP1-AS1 sponged miR-299-3p through 3'-untranslated region (3'-UTR) binding, which in turn relieved the repression of WTAP and thus upregulated WTAP expression. In conclusion, above findings conclude that lncRNA DLGAP1-AS1 promotes BC ADR-resistance through WTAP/DLGAP1-AS1/miR-299-3p feedback loop.

Metformin inhibits hepatocellular carcinoma development by inducing apoptosis and pyroptosis through regulating FOXO3

This study aimed to expand our understanding of metformin (Met) in inhibiting hepatocellular carcinoma (HCC) progression and to investigate its underlying mechanism. Met was administrated to HCC cells at 5, 10, and 20 μM, after which the cell phenotype was evaluated. RNA-seq cluster analysis was used to screen for target genes modulated by Met. Luciferase activity and ChIP assays were performed to detect the effect of FOXO3 on the transcriptional activation of NLRP3. We evaluated the effect of Met and FOXO3 and on the growth of HCC cells in vivo. Met inhibited HCC cell proliferation and promoted apoptosis. Met also induced pyroptosis of HCC cells. FOXO3 was significantly upregulated by Met treatment, and FOXO3 activated transcription of NLRP3. Cells after Met treatment together with FOXO3 knockdown have a stronger colony formation and migration ability but a lower apoptosis rate compared to the Met treatment alone group. In vivo, Met inhibited HCC tumor growth. The tumors in Met treatment and FOXO3 knockdown group grew faster than in Met treatment group. Thus, Met attenuates HCC cell development by inducing apoptosis and pyroptosis. This effect of metformin is partially dependent on FOXO3 which can activate the transcription of NLRP3.