Metformin and Cancer Glucose Metabolism: At the Bench or at the Bedside?

Dataset for analysis of metabolic pathways and their reversibility associated with anti-proliferative effect of metformin in liver cancer cells

Despite epidemiological indications, utility of metformin in liver cancer remains debated and the understanding of the mechanism underlying its anti-cancer effects remains incomplete. Particularly, whether it operates via similar mechanism under glucose-sufficient and glucose- deficient environments or whether these effects are reversible remains unexplored. This metabolomic dataset was collected from liver cancer (HepG2) cells treated with metformin or placebo over a period of 3 h to 48 h as well as from cells recovering after metformin withdrawal. Cells were exposed to placebo or 2.5 mM metformin with or without glucose (5 mM) supplementation. The cells were harvested at 3, 6, 12, 24, and 48 h post-treatment. Cells were also harvested after 24 h of treatment under one of these conditions followed by reversal of glucose and/or metformin exposure status for 48 h. Metabolites from six biological replicates of each experimental group were extracted using chilled monophasic metabolite extraction solvent (Water: Acetonitrile: Isopropanol= 2:3:3) containing homovanillic acid as an internal standard. Samples were derivatized using MOX reagent followed by MSTFA. Untargeted metabolomic profiling of derivatized samples were performed using an Agilent 7890B gas chromatograph coupled to a 5977B single quadrupole mass spectrometer. Analytes were injected through a splitless liner and separated on a HP-5MS ultra-inert column using ultrapure helium as the carrier gas. Peak alignment, annotation, and integration were done using Agilent MassHunter Quantitative analysis software. Multivariate analysis was performed using MetaboAnalyst 5.0. These experiments were performed to unravel the longitudinal evolution of cellular metabolome in response to metformin treatment, its glucose dependence, as well as to examine the reversibility of these changes. The dataset can help to identify glucose-independent pathways involved in anti-cancer effect of metformin. The dataset can be used to design experiments to develop novel therapeutic combinations synergistically acting with metformin to cripple the metabolic fitness of cancer cells. It can also help to develop experiments to test the effect of metformin withdrawal in liver cancer.

TEAD1, MYO7A and NDUFC2 are novel functional genes associated with glucose metabolism in BXD recombinant inbred population

AIM

The liver is an important metabolic organ that governs glucolipid metabolism, and its dysfunction may cause non-alcoholic fatty liver disease, type 2 diabetes mellitus, dyslipidaemia, etc. We aimed to systematic investigate the key factors related to hepatic glucose metabolism, which may be beneficial for understanding the underlying pathogenic mechanisms for obesity and diabetes mellitus.

MATERIALS AND METHODS

Oral glucose tolerance test (OGTT) phenotypes and liver transcriptomes of BXD mice under chow and high-fat diet conditions were collected from GeneNetwork. QTL mapping was conducted to pinpoint genomic regions associated with glucose homeostasis. Candidate genes were further nominated using a multi-criteria approach and validated to confirm their functional relevance in vitro.

RESULTS

Our results demonstrated that plasma glucose levels in OGTT were significantly affected by both diet and genetic background, with six genetic regulating loci were mapped on chromosomes 1, 4, and 7. Moreover, TEAD1, MYO7A and NDUFC2 were identified as the candidate genes. Functionally, siRNA-mediated TEAD1, MYO7A and NDUFC2 knockdown significantly decreased the glucose uptake and inhibited the transcription of genes related to insulin and glucose metabolism pathways.

CONCLUSIONS

Our study contributes novel insights to the understanding of hepatic glucose metabolism, demonstrating the impact of TEAD1, MYO7A and NDUFC2 on mitochondrial function in the liver and their regulatory role in maintaining in glucose homeostasis.

Metformin and Glucose Concentration as Limiting Factors in Retinal Pigment Epithelial Cell Viability and Proliferation

Metformin is a well-established drug for the treatment of type 2 diabetes; however, the mechanism of action has not been well described and many aspects of how it truly acts are still unknown. Moreover, regarding in vitro experiments, the glycaemic status when metformin is used is generally not considered, which, added to the suprapharmacological drug concentrations that are commonly employed in research, has resulted in gaps of its mechanism of action. The aim of this study was to determine how glucose and metformin concentrations influence cell culture. Considering that diabetic retinopathy is one of the most common complications of diabetes, a retinal pigment epithelial cell line was selected, and cell viability and proliferation rates were measured at different glucose and metformin concentrations. As expected, glucose concentration by itself positively influenced cell proliferation rates. When the metformin was considered, results were conditioned, as well, by metformin concentration. This conditioning resulted in cell death when high concentrations of metformin were used under physiological concentrations of glucose, while this did not happen when clinically relevant concentrations of metformin were used independently of glucose status. Our study shows the importance of in vitro cell growth conditions when drug effects such as metformin's are being analysed.

Targeting cellular metabolism in head and neck cancer precision medicine era: A promising strategy to overcome therapy resistance

Head and neck squamous cell carcinoma (HNSCC) is among the most prevalent cancer worldwide, with the most severe impact on quality of life of patients. Despite the development of multimodal therapeutic approaches, the clinical outcomes of HNSCC are still unsatisfactory, mainly caused by relatively low responsiveness to treatment and severe drug resistance. Metabolic reprogramming is currently considered to play a pivotal role in anticancer therapeutic resistance. This review aimed to define the specific metabolic programs and adaptations in HNSCC therapy resistance. An extensive literature review of HNSCC was conducted via the PubMed including metabolic reprogramming, chemo- or immune-therapy resistance. Glucose metabolism, fatty acid metabolism, and amino acid metabolism are closely related to the malignant biological characteristics of cancer, anti-tumor drug resistance, and adverse clinical results. For HNSCC, pyruvate, lactate and almost all lipid categories are related to the occurrence and maintenance of drug resistance, and targeting amino acid metabolism can prevent tumor development and enhance the response of drug-resistant tumors to anticancer therapy. This review will provide a better understanding of the altered metabolism in therapy resistance of HNSCC and promote the development of new therapeutic strategies against HNSCC, thereby contribute to a more efficacious precision medicine.

Association between diabetes and cancer. Current mechanistic insights into the association and future challenges

Compelling pieces of epidemiological, clinical, and experimental research have demonstrated that Diabetes mellitus (DM) is a major risk factor associated with increased cancer incidence and mortality in many human neoplasms. In the pathophysiology context of DM, many of the main classical actors are relevant elements that can fuel the different steps of the carcinogenesis process. Hyperglycemia, hyperinsulinemia, metabolic inflammation, and dyslipidemia are among the classic contributors to this association. Furthermore, new emerging actors have received particular attention in the last few years, and compelling data support that the microbiome, the epigenetic changes, the reticulum endoplasmic stress, and the increased glycolytic influx also play important roles in promoting the development of many cancer types. The arsenal of glucose-lowering therapeutic agents used for treating diabetes is wide and diverse, and a growing body of data raised during the last two decades has tried to clarify the contribution of therapeutic agents to this association. However, this research area remains controversial, because some anti-diabetic drugs are now considered as either promotors or protecting elements. In the present review, we intend to highlight the compelling epidemiological shreds of evidence that support this association, as well as the mechanistic contributions of many of these potential pathological mechanisms, some controversial points as well as future challenges.

Role of the AMPK/SIRT1 pathway in non‑alcoholic fatty liver disease (Review)

Non‑alcoholic fatty liver disease (NAFLD) is an increasingly prevalent ailment worldwide. Moreover, de novo lipogenesis (DNL) is considered a critical factor in the development of NAFLD; hence, its inhibition is a promising target for the prevention of fatty liver disease. There is evidence to indicate that AMP‑activated protein kinase (AMPK) and sirtuin 1 (SIRT1) may play a crucial role in DNL and are the regulatory proteins in type 2 diabetes mellitus, obesity and cardiovascular disease. Therefore, AMPK and SIRT1 may be promising targets for the treatment of NAFLD. The present review article thus aimed to summarize the findings of clinical studies published during the past decade that suggested the beneficial effects of AMPK and SIRT1, using their specific activators and their combined effects on fatty liver disease.

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 Intervention—A Panacea for Cancer Treatment?

The molecular mechanism of action and the individual influence of various metabolic pathways related to metformin intervention are under current investigation. The available data suggest that metformin provides many advantages, exhibiting anti-inflammatory, anti-cancer, hepatoprotective, cardioprotective, otoprotective, radioprotective, and radio-sensitizing properties depending on cellular context. This literature review was undertaken to provide novel evidence concerning metformin intervention, with a particular emphasis on cancer treatment and prevention. Undoubtedly, the pleiotropic actions associated with metformin include inhibiting inflammatory processes, increasing antioxidant capacity, and improving glycemic and lipid metabolism. Consequently, these characteristics make metformin an attractive medicament to translate to human trials, the promising results of which were also summarized in this review.

6-Shogaol Antagonizes the Adipocyte-Conditioned Medium-Initiated 5-Fluorouracil Resistance in Human Colorectal Cancer Cells through Controlling the SREBP-1 Level

The resistance of colorectal cancer (CRC) to chemotherapy, e.g., 5-fluorouracil (5-FU), is an impediment to successful cancer treatment. Although many mechanisms have been proposed to explain the occurrence of resistance, little is known concerning the role of the adipocyte-containing microenvironment of CRC. Accumulating data have proposed that the combined therapy of clinical drugs with ginger derivatives, e.g., 6-shogaol, might improve resistance development. In the present study, we examined the effect of adipocyte-conditioned medium (ACM) on 5-FU-treated CRC cells (human DLD-1 and SW480 cells) and further examined the possible antagonized role of 6-shogaol in this situation. It was shown that the level of sterol-regulatory element-binding protein-1 (SREBP-1), a critical transcription factor involved in lipid synthesis and metabolism, would be upregulated through Akt and p70S6K signaling pathways while CRC cells are cultured in ACM, which subsequently decreases the cell sensitivity to 5-FU cytotoxicity. Moreover, our results also demonstrated the antagonized role of 6-shogaol in attenuating the ACM effects on CRC cells through activating AMPK signaling. Overall, the present study elucidated the role of adipocyte-containing microenvironment in 5-FU resistance development of CRC through controlling the SREBP-1 level and further enhanced the concept of clinical application of 6-shogaol and AMPK signaling in CRC therapy.