bims-medica Biomed News
on Metabolism and diet in cancer
Issue of 2024–12–01
thirty-two papers selected by
Brett Chrest, Wake Forest University



  1. Cell Rep. 2024 Nov 21. pii: S2211-1247(24)01339-1. [Epub ahead of print]43(12): 114988
      Cancer cells often use alternative nutrient sources to support their metabolism and proliferation. One important alternative nutrient source for many cancers is acetate. Acetate is metabolized into acetyl-coenzyme A (CoA) by acetyl-CoA synthetases 1 and 2 (ACSS1 and ACSS2), which are found in the mitochondria and cytosol, respectively. We show that ACSS1 and ACSS2 are differentially expressed in cancer. Melanoma, breast cancer, and acute myeloid leukemia cells expressing ACSS1 readily use acetate for acetyl-CoA biosynthesis and to fuel mitochondrial metabolism. ACSS1-dependent acetate metabolism decreases the relative contributions of glucose and glutamine to the tricarboxylic acid (TCA) cycle and alters the pentose phosphate pathway and redox state of cancer cells. ACSS1 knockdown decreases acute myeloid leukemia burden in vivo and inhibits melanoma tumor and metastatic growth. Our study highlights a key role for ACSS1-dependent acetate metabolism for cancer growth, raising the potential for ACSS1-targeting therapies in cancer.
    Keywords:  ACSS1; ACSS2; ACSS2 inhibitor; AML; CP: Cancer; CP: Metabolism; acetate; cancer; melanoma; metabolism; metastasis
    DOI:  https://doi.org/10.1016/j.celrep.2024.114988
  2. Nutrients. 2024 Nov 16. pii: 3919. [Epub ahead of print]16(22):
       BACKGROUND: High-fat diets (HFDs) have been associated with an increased risk of pancreatic cancer. In contrast, ketogenic diets (KDs) have been shown to display anti-tumor characteristics. The objective of this work was to evaluate the efficacy of a KD on late-stage pancreatic carcinogenesis in a genetically modified mouse model of pancreatic cancer [LSL-KrasG12D/+; Ptf1-Cre (KC) mice], as well as its liver safety, and to compare it to that of an HFD.
    METHODS: Six-month-old female and male KC mice were randomly allocated to either a control diet (CD) (%kcal: 20% fat, 15% protein, 65% carbohydrates), an HFD (%kcal: 40% fat, 15% protein, 45% carbohydrate) or a KD (%kcal: 84% fat, 15% protein, 1% carbohydrate) and fed these diets for 6 months.
    RESULTS: HFD-fed, but not KD-fed, mice showed a 15% increase in body weight, plus elevated serum insulin (2.4-fold increase) and leptin (2.9-fold increase) levels, compared to CD-fed mice. At the pancreas level, no differences in pancreatic cancer incidence rates were observed among the diet groups. Regarding the liver safety profile, the HFD-fed mice had higher serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP), when compared to the CD and KD groups. In addition, upon histologic examination, an HFD, but not a KD, showed a ~2-fold increase in both macro- and microsteatosis, as well as 35% and 32% higher levels of TLR4 and NF-κB activation, respectively, compared to CD-fed mice.
    CONCLUSIONS: In summary, although a KD intervention alone did not prevent pancreatic carcinogenesis, our data suggests that a KD modulates insulin signaling and hepatic lipid metabolism, highlighting its beneficial effects on healthspan and liver function when compared to an HFD.
    Keywords:  high-fat diet; ketogenic diet; pancreatic cancer; pancreatic carcinogenesis
    DOI:  https://doi.org/10.3390/nu16223919
  3. Nat Metab. 2024 Nov 26.
      Cancer cells often experience nutrient-limiting conditions because of their robust proliferation and inadequate tumour vasculature, which results in metabolic adaptation to sustain proliferation. Most cancer cells rapidly consume glucose, which is severely reduced in the nutrient-scarce tumour microenvironment. In CRISPR-based genetic screens to identify metabolic pathways influenced by glucose restriction, we find that tumour-relevant glucose concentrations (low glucose) protect cancer cells from inhibition of de novo pyrimidine biosynthesis, a pathway that is frequently targeted by chemotherapy. We identify two mechanisms to explain this result, which is observed broadly across cancer types. First, low glucose limits uridine-5-diphosphate-glucose synthesis, preserving pyrimidine nucleotide availability and thereby prolonging the time to replication fork stalling. Second, low glucose directly modulates apoptosis downstream of replication fork stalling by suppressing BAK activation and subsequent cytochrome c release, key events that activate caspase-9-dependent mitochondrial apoptosis. These results indicate that the low glucose levels frequently observed in tumours may limit the efficacy of specific chemotherapeutic agents, highlighting the importance of considering the effects of the tumour nutrient environment on cancer therapy.
    DOI:  https://doi.org/10.1038/s42255-024-01166-w
  4. Am J Physiol Cell Physiol. 2024 Nov 29.
      The TCA cycle serves as a central hub to balance catabolic and anabolic needs of the cell, where carbon moieties can either contribute to oxidative metabolism or support biosynthetic reactions. This differential TCA cycle engagement for glucose-derived carbon has been extensively studied in cultured cells, but the fate of fatty acid (FA)-derived carbons is poorly understood. To fill the knowledge gap, we have developed a strategy to culture cells with long-chain FAs without altering cell viability. By tracing 13C-FA we show that FA oxidation (FAO) is robust in both proliferating and oxidative cells while the metabolic pathway after citrate formation is distinct. In proliferating cells, a significant portion of carbon derived from FAO exits canonical TCA cycle as citrate and converts to unlabeled malate in cytosol. Increasing FA supply or b-oxidation does not change the partition of FA-derived carbon between cytosol and mitochondria. Oxidation of glucose competes with FA derived carbon for the canonical TCA pathway thus promoting FA carbon flowing into the alternative TCA pathway. Moreover, the coupling between FAO and the canonical TCA pathway changes with the state of oxidative energy metabolism.
    Keywords:  13C stable isotope tracing; FAO; TCA cycle; oxygen consumption rate
    DOI:  https://doi.org/10.1152/ajpcell.00611.2023
  5. J Vis Exp. 2024 Nov 08.
      Metabolism is mainly coordinated by cellular energy availability and environmental conditions. Assays for knowing how cells adapt energetic metabolism to different nutritional and environmental conditions give valuable information to elucidate molecular mechanisms. Oxidative phosphorylation is the primary source of ATP in most cells, and mitochondrial respiration activity is a key component of oxidative phosphorylation, maintaining mitochondrial membrane potential for ATP synthesis. Mitochondrial respiration is often studied in isolated mitochondria that are missing the cellular context. Here, we present a method for quantifying mitochondrial respiration in yeast-intact cells. This method applies to any yeast species, although it has been generally used for Saccharomyces cerevisiae cells. First, the yeast growth in specific conditions is tested. Then, cells are washed and resuspended in deionized water with a 1:1 ratio (w/v). Cells are then placed in an oximeter chamber with constant stirring, and a Clark electrode is used to quantify oxygen consumption. Some molecules are sequentially placed into the chamber and selected according to this effect on the electron transport chain or ATP synthesis. ATPase inhibitor oligomycin is first added to measure respiration coupled to ATP synthesis. Afterward, an uncoupler is used to measure the maximal respiratory capacity. Finally, a mix of electron transport chain inhibitors is added to discard oxygen consumption unrelated to mitochondrial respiration. Data are analyzed using a linear regression to obtain the slope, representing the oxygen consumption rate. The advantage of this method is that it is specific for yeast mitochondrial respiration, maintaining the cellular context. It is essential to highlight that inhibitors used in mitochondrial respiration quantification could vary between yeast species.
    DOI:  https://doi.org/10.3791/67186
  6. Commun Biol. 2024 Nov 26. 7(1): 1576
      Cell membrane glycans contribute to immune recognition, signaling, and cellular adhesion and migration, and altered membrane glycosylation is a feature of cancer cells that contributes to cancer progression. The uptake and metabolism of glucose and other nutrients essential for glycan synthesis could underlie altered membrane glycosylation, but the relationship between shifts in nutrient metabolism and the effects on glycans have not been directly examined. We developed a method that combines stable isotope tracing with metabolomics to enable direct observations of glucose allocation to nucleotide sugars and cell-membrane glycans. We compared the glucose allocation to membrane glycans of two pancreatic cancer cell lines that are genetically identical but have differing energy requirements. The 8988-S cells had higher glucose allocation to membrane glycans and intracellular pathways relating to glycan synthesis, but the 8988-T cells had higher glucose uptake and commitment of glucose to non-glycosylation pathways. The cell lines differed in the requirements of glucose for energy production, resulting in differences in glucose bioavailability for glycan synthesis. The workflow demonstrated here enables studies on the effects of metabolic shifts on the commitment of nutrients to cell-membrane glycans. The results suggest that cell-membrane glycans are remodeled through shifts in glucose commitment to non-glycosylation pathways.
    DOI:  https://doi.org/10.1038/s42003-024-07277-0
  7. Crit Rev Oncol Hematol. 2024 Nov 22. pii: S1040-8428(24)00314-7. [Epub ahead of print] 104571
    Italian Intersociety Working Group for Nutritional Support in Cancer Patients
      Cancer is currently one of the biggest public health challenges worldwide, ranking as the second leading cause of death globally. To date, strong epidemiological associations have been demonstrated between unhealthy lifestyles and eating habits, i.e. obesity, and an increased risk of developing cancer. However, there is limited evidence regarding the impact of specific dietary regimes on cancer outcomes during conventional cancer treatments. This paper systematically reviews and evaluates preclinical and clinical evidence regarding the effects of fasting, fast-mimicking diet, ketogenic diet, vegan diet, alkaline diet, paleolithic diet, the Gerson regimen, and macrobiotic diet in the context of cancer treatments. Clinical trials on dietary regimes as complementary cancer therapy are limited by significant differences in trial design, patient characteristics, and cancer type, making it difficult to draw conclusions. In the future, more uniformly controlled clinical trials should help to better define the role of diets in cancer management.
    Keywords:  cancer; fasting; fasting mimicking diet; ketogenic diet; macrobiotic diet; paleolithic diet; the Gerson regimen; vegan diet
    DOI:  https://doi.org/10.1016/j.critrevonc.2024.104571
  8. Cold Spring Harb Perspect Med. 2024 Nov 25. pii: a041657. [Epub ahead of print]
      Cancer is caused by mutations that drive aberrant growth, proliferation, and invasion, thus overriding regulatory mechanisms that normally link these processes to organismal needs and cellular physiology. This imposes demands for the production of energy and biomass and for survival in microenvironments that are often nonphysiologic and nutrient-poor, which are met by rewiring of cellular metabolism. The resultant dependence of tumor cells on altered metabolism can induce sensitivity to specific metabolic perturbations that can be exploited for cancer therapy. Some cancers are caused by mutations that impart a novel function to metabolic enzymes, leading to the production of a tumor-promoting metabolite that is dispensable in normal cells, representing an ideal therapeutic target. Tumors can also exploit metabolic regulation of cellular immunity to evade antitumor immune responses, and deciphering this biology has revealed potential targets for therapeutic intervention. Here, we discuss a number of illustrative examples highlighting the therapeutic potential and the challenges of targeting metabolism for cancer therapy.
    DOI:  https://doi.org/10.1101/cshperspect.a041657
  9. Diabetol Metab Syndr. 2024 Nov 28. 16(1): 288
       BACKGROUND: Leptin, an energy balance regulator secreted by adipocytes, increases metastatic potential of breast cancer cells. The impact on cancer cell metabolism remains unclear given that most studies of leptin and breast cancer cell metabolism utilize supraphysiological glucose concentrations.
    METHODS: Using two murine models of metastatic triple-negative breast cancer (TNBC) differing in genetic alterations (4T1: p53 and Pik3ca mutations; metM-Wntlung: increased Wnt signaling) and cultured in physiological (5 mM) glucose media, we tested the hypothesis that leptin increases migration of metastatic breast cancer cells through regulation of glucose metabolism.
    RESULTS: Our results showed that leptin treatment, compared with vehicle, increased cell migration in each cell line, with decreased leptin receptor (Ob-R) mRNA expression in 4T1, but not metM-Wntlung, cells. AMP-activated protein kinase (AMPK) was activated in 4T1 with leptin treatment but decreased in metM-Wntlung. Leptin decreased fatty acid synthase (Fasn) and carnitine palmitoyltransferase 1a (Cpt1a) mRNA expression in 4T1 cells but increased their expression in metM-Wntlung cells. Fatty acid oxidation was not necessary for leptin-induced migration in either cell line. Leptin increased palmitate synthesis from glucose in metM-Wntlung, but not 4T1 cells. Moreover, although leptin increased glucose transporter 1 (Glut1) mRNA expression in both cell lines and inhibition of glycolysis blocked leptin-induced migration in metM-Wntlung, but not 4T1 cells.
    CONCLUSION: Taken together, these results demonstrate that at physiological glucose concentrations, leptin increases migration of 4T1 and metM-Wntlung cells via shared and distinct effects on energy metabolism, suggesting that the type of TNBC genetic alteration plays a role in differential metabolic regulation of leptin-induced migration.
    Keywords:  Breast cancer; Fatty acid; Glucose; Leptin
    DOI:  https://doi.org/10.1186/s13098-024-01535-1
  10. Curr Opin Hematol. 2024 Nov 19.
       PURPOSE OF REVIEW: The aim of this review is to highlight the importance of lipids' intricate and interwoven role in mediating diverse acute myeloid leukemia (AML) processes, as well as potentially novel lipid targeting strategies. This review will focus on new studies of lipid metabolism in human leukemia, particularly highlighting work in leukemic stem cells (LSCs), where lipids were assessed directly as a metabolite.
    RECENT FINDINGS: Lipid metabolism is essential to support LSC function and AML survival through diverse mechanisms including supporting energy production, membrane composition, signaling pathways, and ferroptosis. Recent work has highlighted the role of lipid rewiring in metabolic plasticity which can underlie therapy response, the impact of cellular and genetic heterogeneity in AML on lipid metabolism, and the discovery of noncanonical roles of lipid related proteins in AML.
    SUMMARY: Recent findings around lipid metabolism clearly demonstrates their importance to our understanding and therapeutic targeting of AML. We have only begun to unravel the regulation and utilization of lipids in this disease. Further, understanding the layered dynamics of lipid homeostasis could provide novel opportunities to target lipid metabolism in AML and LSCs with the potential of improving outcomes for patients with AML.
    DOI:  https://doi.org/10.1097/MOH.0000000000000853
  11. bioRxiv. 2024 Nov 15. pii: 2024.11.14.621733. [Epub ahead of print]
      Reducing calorie intake without malnutrition limits tumor progression but the underlying mechanisms are poorly understood. Here we show that dietary restriction (DR) suppresses tumor growth by enhancing CD8 + T cell-mediated anti-tumor immunity. DR reshapes CD8 + T cell differentiation within the tumor microenvironment (TME), promoting the development of effector T cell subsets while limiting the accumulation of exhausted T (Tex) cells, and synergizes with anti-PD1 immunotherapy to restrict tumor growth. Mechanistically, DR enhances CD8 + T cell metabolic fitness through increased ketone body oxidation (ketolysis), which boosts mitochondrial membrane potential and fuels tricarboxylic acid (TCA) cycle-dependent pathways essential for T cell function. T cells deficient for ketolysis exhibit reduced mitochondrial function, increased exhaustion, and fail to control tumor growth under DR conditions. Our findings reveal a critical role for the immune system in mediating the anti-tumor effects of DR, highlighting nutritional modulation of CD8 + T cell fate in the TME as a critical determinant of anti-tumor immunity.
    DOI:  https://doi.org/10.1101/2024.11.14.621733
  12. Biomolecules. 2024 Nov 12. pii: 1437. [Epub ahead of print]14(11):
      The fundamental biological characteristics of tumor cells are characterized by irregularities in signaling and metabolic pathways, which are evident through increased glucose uptake, altered mitochondrial function, and the ability to evade growth signals. Interventions such as fasting or fasting-mimicking diets represent a promising strategy that can elicit distinct responses in normal cells compared to tumor cells. These dietary strategies can alter the circulating levels of various hormones and metabolites, including blood glucose, insulin, glucagon, growth hormone, insulin-like growth factor, glucocorticoids, and epinephrine, thereby potentially exerting an anticancer effect. Additionally, elevated levels of insulin-like growth factor-binding proteins and ketone bodies may increase tumor cells' dependence on their own metabolites, ultimately leading to their apoptosis. The combination of fasting or fasting-mimicking diets with radiotherapy or chemotherapeutic agents has demonstrated enhanced anticancer efficacy. This paper aims to classify fasting, elucidate the mechanisms that underlie its effects, assess its impact on various cancer types, and discuss its clinical applications. We will underscore the differential effects of fasting on normal and cancer cells, the mechanisms responsible for these effects, and the imperative for clinical implementation.
    Keywords:  cancer; cellular autophagy; clinical applications; energy restriction; fasting; metabolism
    DOI:  https://doi.org/10.3390/biom14111437
  13. J Am Chem Soc. 2024 Nov 29.
      Fatty acid de novo synthesis (FADNS) is a critical process in lipogenesis that is characteristically altered in clear cell renal cell carcinoma (ccRCC), which is the major type of kidney cancer. An important challenge in studying the FADNS process has been the accurate measurement of cytosolic lipogenic acetyl-CoA (AcCoA), the precursor in FADNS, due to its compartmentalization within cells. Here, we describe a novel NMR-based method to decode the isotopic enrichment of lipogenic AcCoA, which, as we demonstrated, is encoded in the simple signal ratios of the geminal methyl groups of lanosterol during its biosynthesis. The approach was validated based on the independence of the tracer enrichment and species along with the expected FADNS modulation using differentially enriched tracers and a well-studied drug. Application of this technique to 786-O ccRCC cells showed that glucose may serve as a major carbon source for lipogenic AcCoA in FADNS at physiological nutrient concentrations, at odds with previous studies that indicated glutamine's dominant role through reductive carboxylation under higher nutrient conditions. Further investigation into glutamine's alternative roles in ccRCC cells suggested its major involvement in the bioenergetic TCA cycle, pyrimidine synthesis, and glutathione synthesis, which is also critical in ccRCC growth. The glutamine-dependent glutathione synthesis was also suggested as a possible metabolic vulnerability compared to normal kidney cells using a glutathione synthesis inhibitor. The current study provides a simple tool for studying an important aspect of lipid metabolism and suggests translational implications for targeting glucose-driven lipogenesis and glutamine-supported glutathione synthesis in ccRCC.
    DOI:  https://doi.org/10.1021/jacs.4c11809
  14. Mol Genet Metab. 2024 Nov 10. pii: S1096-7192(24)00494-3. [Epub ahead of print]143(4): 108610
       BACKGROUND: This study aimed to explore the feasibility, safety and efficacy of a Modified Atkins Diet (MAD) in patients with mitochondrial myopathy (MM).
    METHODS: Patients with genetically proven mitochondrial disorder and exercise intolerance or muscle weakness followed a twelve week MAD. Feasibility was measured by diet duration and ketone levels. Safety was assessed by monitoring adverse events (AE). Efficacy was assessed by a maximal incremental test and a muscle performance test.
    RESULTS: Eight out of twenty patients completed the twelve week intervention. Reasons to discontinue were the occurrence of AE: rhabdomyolysis (n = 3), vomiting (n = 1), fatigue (n = 6), constipation (n = 1), in combination with a lack of improvement and adherence difficulties. On an individual level, various positive effects were reported including improvements in VO2peak (n = 6), anaerobic threshold (n = 9), muscle fatigue resistance (n = 5), muscle strength (n = 7), fatigue (n = 6), glucose tolerance (n = 7), migraine (n = 3), sleep (n = 3), and gastrointestinal complaints (n = 2). Lipid profile improved and thirteen patients lost weight. All patients with mitochondrial DNA (mtDNA) deletions, experienced muscle related AE. The five patients with the m.3243A>G mutation achieved the longest diet duration.
    DISCUSSION/CONCLUSION: MAD feasibility, safety and efficacy is variable in MD patients. MAD appears to be unsuitable for MD patients with mtDNA deletions. All patients should be monitored closely for adverse events when initiating the diet. Further research should focus on predictive factors to consider the diet, effectiveness of less stringent carbohydrate restricted diets.
    Keywords:  Adverse event; Ketogenic diet; Maximal incremental testing; Mitochondrial DNA deletion; Mitochondrial myopathy; Modified Atkins diet
    DOI:  https://doi.org/10.1016/j.ymgme.2024.108610
  15. Drug Resist Updat. 2024 Nov 26. pii: S1368-7646(24)00135-3. [Epub ahead of print]78 101177
      Immunotherapy, either alone or in combination with chemotherapy, has demonstrated limited efficacy in a variety of solid cancers. Several factors contribute to explaining primary or secondary resistance. Among them, cancer cells, whose metabolism frequently relies on aerobic glycolysis, promote exhaustion of cytotoxic immune cells by diverting the glucose in the tumor microenvironment (TME) to their own profit, while secreting lactic acid that sustains the oxidative metabolism of immunosuppressive cells. Here, we propose to combine current treatment based on the use of immune checkpoint inhibitors (ICIs) with high doses of sodium citrate (SCT) because citrate inhibits cancer cell metabolism (by targeting both glycolysis and oxidative metabolism) and may active anti-tumor immune response. Indeed, as showed in preclinical studies, SCT reduces cancer cell growth, promoting cell death and chemotherapy effectiveness. Furthermore, since the plasma membrane citrate carrier pmCIC is mainly expressed in cancer cells and low or not expressed in immune and non-transformed cells, we argue that the inhibition of cancer cell metabolism by SCT may increase glucose availability in the TME, thus promoting functionality of anti-tumor immune cells. Concomitantly, the decrease in the amount of lactic acid in the TME may reduce the functionality of immunosuppressive cells. Preclinical studies have shown that SCT can enhance the anti-tumor immune response through an enhancement of T cell infiltration and activation, and a repolarization of macrophages towards a TAM1-like phenotype. Therefore, this simple and cheap strategy may have a major impact to increase the efficacy of current immunotherapies in human solid tumors and we encourage testing it in clinical trials.
    Keywords:  ICI; cancer; citrate; immunotherapy; lactate; metabolism
    DOI:  https://doi.org/10.1016/j.drup.2024.101177
  16. Am J Clin Nutr. 2024 Nov 25. pii: S0002-9165(24)01415-1. [Epub ahead of print]
       BACKGROUND: Numerous prospective cohort studies have investigated the influence of dietary patterns on the risks of various cancers, although the findings differed.
    OBJECTIVE: To evaluate the associations of dietary patterns with risks of various cancers and assess the strength and validity of the evidence.
    METHODS: Relevant articles were retrieved from the PubMed, EMBASE, Web of Science, and Cochrane library databases from inception to February 22, 2024. The included systematic reviews were meta-analyses of prospective cohort studies that reported an effect size to calculate the association between dietary patterns and cancer risk. The quality of the included studies was evaluated using a measurement tool to assess systematic reviews and the certainty of evidence was assessed using credibility assessment of evidence. Outcomes of interest included any incident cancers. This study was registered with PROSPERO (CRD42023425237).
    RESULTS: Overall, 74 meta-analyses from 30 articles were identified. Three meta-analyses (4.1%) were graded as convincing evidence and included associations between adherence to the 2007 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) dietary recommendations (per 1-unit score increase) and lower risk of all cancers (relative risk [RR] = 0.93, 95% confidence interval [CI]: 0.92-0.95), while negative associations were found comparing the highest vs. lowest categories for a prudent diet (RR = 0.89, 95% CI: 0.85-0.93) and vegetable-fruit-soybean diet (RR = 0.87, 95% CI: 0.83-0.92) in relation to breast cancer. After credibility assessment of evidence by Grading of Recommendations, Assessment, Development, and Evaluation, four (5.4%) meta-analyses were classified as high, including adherence to the 2007 WCRF/AICR dietary recommendations and decreased risks of all cancers, breast cancer, colorectal cancer, and prostate cancer.
    CONCLUSION: These findings suggest that adherence to certain healthy dietary patterns is associated with lower risk of all cancers and certain individual cancers.
    REGISTER: This study was registered with PROSPERO (CRD42023425237). crd.york.ac.uk/PROSPERO/display_record.php?RecordID=425237.
    Keywords:  Cancer; Cohort studies; Diet pattern; Risk; Umbrella review
    DOI:  https://doi.org/10.1016/j.ajcnut.2024.11.020
  17. Eur J Nutr. 2024 Nov 28. 64(1): 33
       PURPOSE: Unhealthy dietary patterns contribute to an increased risk of colorectal cancer (CRC). Limited prior research has used reduced rank regression (RRR) to assess dietary patterns relative to CRC risk. This study aimed to identify dietary patterns derived by RRR and assess their associations with CRC risk and mortality.
    METHODS: We used data from the multicentre Prostate, Lung, Colorectal, and Ovarian Cancer Screening (PLCO) trial. Dietary intake was assessed using a Dietary History Questionnaire. In the RRR intake of fibre, folate, and the percentage of energy from carbohydrates, saturated and unsaturated fatty acids were used as response variables. Cox models and competing risk survival regression, with age as the time scale, were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for CRC risk and mortality, respectively.
    RESULTS: The median follow-up time for CRC risk (n = 1044) and mortality (n = 499) was 9.4 years (Interquartile Range: 8. 0, 10.1) and 16.9 years (11.9, 18.6), respectively. Two dietary patterns were identified: the first was characterised by high carbohydrate, folate and low fatty acid intake, and the second by high fibre and unsaturated fatty acid. Compared to participants in the first tertile of the high fibre and unsaturated fatty acid pattern, those in the third tertile had a lower risk of CRC (HR = 0.88; 95% CI: 0.76, 1.03), and colon cancer (HR = 0.85; 95% CI: 0.72, 1.01). Conversely, the high carbohydrate, high folate and low fatty acid pattern had no association with CRC outcomes. None of the dietary patterns showed associations with rectal cancer or CRC mortality.
    CONCLUSION: A diet enriched with high fibre and unsaturated fatty acids may reduce the risk of CRC. These results highlight the potential protective effect of adequate fibre intake in conjunction with high consumption of unsaturated fatty acids against CRC.
    Keywords:  Colorectal cancer; Healthy diet; Hybrid dietary data analysis; Longitudinal data; Reduced rank regression; Survival analysis
    DOI:  https://doi.org/10.1007/s00394-024-03513-9
  18. Biomedicines. 2024 Oct 29. pii: 2481. [Epub ahead of print]12(11):
       BACKGROUND: Glioblastoma is the most common and aggressive primary brain tumour, characterised by its invasive nature and complex metabolic profile. Emerging research highlights the role of amino acids (AAs) in glioblastoma metabolism, influencing tumour growth and the surrounding microenvironment.
    METHODS: This narrative review synthesises recent pre-clinical studies focusing on the metabolic functions of AAs in glioblastoma. Key areas include the effects of AA deprivation on tumour growth, adaptive mechanisms, and the tumour microenvironment.
    RESULTS: The effects related to arginine, glutamine, methionine, and cysteine deprivation have been more extensively reported. Arginine deprivation in arginine-auxotrophic glioblastomas induces apoptosis and affects cell adhesion, while glutamine deprivation disrupts metabolic pathways and enhances autophagy. Methionine and cysteine deprivation impact lipid metabolism and ferroptosis. Tumour adaptive mechanisms present challenges, and potential compensatory responses have been identified. The response of the microenvironment to AA deprivation, including immune modulation, is critical to determining therapeutic outcomes.
    CONCLUSIONS: Targeting AA metabolism offers a promising approach for glioblastoma treatment, with potential targeted drugs showing clinical promise. However, the complexity of tumour adaptive mechanisms and their impact on the microenvironment necessitates further research to optimise combination therapies and improve therapeutic efficacy.
    Keywords:  amino acid deprivation; cancer metabolism; glioblastoma; high-grade gliomas
    DOI:  https://doi.org/10.3390/biomedicines12112481
  19. bioRxiv. 2024 Nov 15. pii: 2024.11.13.623431. [Epub ahead of print]
       Objective: Glucagon-like peptide 1 receptor agonists (e.g. semaglutide) potently induce weight loss and thereby reducing obesity-related complications. However, weight regain occurs when treatment is discontinued. An increase in skeletal muscle oxidative phosphorylation (OXPHOS) efficiency upon diet-mediated weight loss has been described, which may contribute to reduced systemic energy expenditure and weight regain. We set out to determine the unknown effect of semaglutide on muscle OXPHOS efficiency.
    Methods: C57BL/6J mice were fed a high-fat diet for 12 weeks before receiving semaglutide or vehicle for 1 or 3 weeks. The rate of ATP production and O 2 consumption were measured by a high-resolution respirometry and fluorometry to determine OXPHOS efficiency in skeletal muscle at these 2 timepoints.
    Results: Semaglutide treatment led to significant reductions in fat and lean mass. Semaglutide improved skeletal muscle OXPHOS efficiency, measured as ATP produced per O 2 consumed (P/O) in permeabilized muscle fibers. Mitochondrial proteomic analysis revealed changes restricted to two proteins linked to complex III assembly (Lyrm7 and Ttc1, p <0.05 without multiple corrections) without substantial changes in the abundance of OXPHOS subunits.
    Conclusions: These data indicate that weight loss with semaglutide treatment increases skeletal muscle mitochondrial efficiency. Future studies could test whether it contributes to weight regain.
    DOI:  https://doi.org/10.1101/2024.11.13.623431
  20. Br J Cancer. 2024 Nov 28.
       BACKGROUND: Individuals with normal weight obesity (NWO) often escape the attention of healthcare providers who may assume that a normal body mass index (BMI) correlates with low health risks. However, it remains unknown whether NWO increases the risk of breast cancer.
    METHODS: This study included 22,257 and 52,506 pre- and postmenopausal females with normal BMI in the UK Biobank. NWO was defined as participants with a normal BMI (18.5-24.9 kg/m2) and an excess percent body fat (PBF > 33.3%). Cox proportional hazard models were used to investigate the associations of NWO and NWO-related biomarkers with incident breast cancer.
    RESULTS: NWO was not associated with premenopausal breast cancer, whereas it was associated with a higher risk of postmenopausal breast cancer (hazard ratio = 1.19, 95% CI: 1.08-1.31). In our meta-analysis, per 5-unit increment in percent body fat level was linked to a 15% (95% CI: 10-19%) elevated risk of postmenopausal breast cancer in females with normal BMI. Stratified analyses showed a stronger positive association in females with higher genetic risk. In our NWO-biomarkers analyses, NWO was linked to 34 identified biomarkers, of which three inflammation markers (monocyte count, neutrophil count, and C-reactive protein), and one ketone body metabolite (β-Hydroxybutyrate) also indicated a positive association with postmenopausal breast cancer.
    CONCLUSIONS: NWO is associated with an increased risk of postmenopausal breast cancer, indicating that relying solely on BMI neglects the higher risk faced by non-obese postmenopausal women.
    DOI:  https://doi.org/10.1038/s41416-024-02906-1
  21. Clin Transl Oncol. 2024 Nov 29.
       BACKGROUND: The association between mitochondrial dysfunction and multiple metabolic adaptations is increasingly being proven. We previously elucidated that mitochondrial complex I deficiency can promote glycolysis in mut-p53 SW480 cells. However, studies have revealed a phenotype with attenuated glycolysis but enhanced fatty acid oxidation (FAO) in invasive tumors. The interplay between complex I and FAO in carcinogenesis remains obscure.
    METHODS: The p53 wild-type RKO cells were exposed to rotenone over at least 2 months to acquire rotenone adaptation cells. Then the transwell invasion assays and expression of metabolic enzymes were first detected in rotenone adaptation cells to illustrate whether rotenone adaptation is correlated with the invasion and FAO. The levels of epithelial-to-mesenchymal transition (EMT)-related proteins and acetyl-CoA in rotenone adaptation cells treated with etomoxir (ETO) and acetate were evaluated to verify the role of CPT1A in regulating invasion. Finally, the levels of reactive oxygen species (ROS) were detected. Meanwhile, the invasiveness and histone acetylation levels of rotenone adaptation cells were observed after adding an ROS inhibitor (N-acetyl-L-cysteine NAC) to demonstrate the molecular connection between FAO and invasion during rotenone adaptation.
    RESULTS: We found long-term exposure to rotenone (a mitochondrial complex I inhibitor) led to EMT and high CPT1A expression in wt-p53 colon cancer. The inhibition of CPT1A suppressed the invasion and reduced histone acetylation, which was rescued by supplementing with acetate. Mechanistically, ROS is crucial for lipid metabolism remodeling.
    CONCLUSION: Our study provides a novel understanding of the role of complex I in lipid reprogramming facilitating colon cancer invasion and metastasis.
    Keywords:  CPT1A; Histone acetylation; Migration and invasion; Mitochondrial complex I; Rotenone
    DOI:  https://doi.org/10.1007/s12094-024-03785-x
  22. Cold Spring Harb Perspect Med. 2024 Nov 25. pii: a041711. [Epub ahead of print]
      Growing evidence indicates that childhood cancer is a developmental disease and the oncogenic impact of mutations depends on spatiotemporal developmental contexts. This dependency leads to distinct molecular, genetic, and clinical characteristics across various cancer (sub)types. However, the underlying molecular mechanisms of tumorigenesis are not fully understood, and the development of precision medicine for childhood cancers is still an ongoing effort, partially due to their relative rarity. Therefore, it is crucial to develop and use "developmental models" that replicate both mutations and specific developmental contexts that determine their impact. In this review, we summarize recent advances in the growing field of developmental modeling of childhood cancers, which enhance our understanding of the pathogenic mechanisms and pave the way for the development of new therapeutic approaches.
    DOI:  https://doi.org/10.1101/cshperspect.a041711
  23. Cancers (Basel). 2024 Nov 20. pii: 3886. [Epub ahead of print]16(22):
      Background: Cladribine-based combination chemotherapy has demonstrated promising efficacy in patients with relapsed/refractory adult acute myeloid leukemia (AML), prompting its increased utilization in the frontline; in pediatrics, it has been typically reserved for relapsed or refractory cases. While fludarabine has been used more commonly as a purine analog in intensive regimens, cladribine may be an important alternative. Methods: We performed a retrospective study at MD Anderson Cancer Center from January 2015 to July 2023, which included patients aged 1-21 years with refractory or relapsed AML who received cladribine outside of a transplant conditioning. Results: A total of 30 patients were included, with a median age of 20 years (range, 2-21), and 55% being male. Similar to adults, cladribine exhibited good tolerability in pediatric and adolescent patients, with the most common adverse events being febrile neutropenia and myelosuppression. The most common grade 3 or 4 adverse events included febrile neutropenia (55%) and sepsis (26%), and there were no treatment discontinuations due to adverse events. Among patients with a median number of 2 (0-7) prior treatments, the overall response rate (CR/CRi) was 45%, and median event-free and overall survival were 6 and 12 months, respectively. Disease progression resulted in 4 deaths within 30 days of treatment. Conclusions: Cladribine was tolerated in pediatrics. No new safety signals were seen with cladribine regimens in this cohort. Response assessment is limited due to the heavily pretreated cohort. Further prospective studies are warranted on the safety and efficacy of cladribine and establish its role in pediatric, adolescent, and early young adult patients with AML.
    Keywords:  acute myeloid leukemia; adolescents; cladribine; leukemia; pediatrics; purine analog
    DOI:  https://doi.org/10.3390/cancers16223886
  24. Am J Clin Nutr. 2024 Nov 25. pii: S0002-9165(24)01418-7. [Epub ahead of print]
       BACKGROUND: Non-nutritive sweeteners (NNS) are used to replace added sugar, yet whether NNS consumers have better or worse diet quality compared to non-consumers is unclear.
    OBJECTIVE: Investigate cross-sectional associations between NNS consumption and diet quality.
    METHODS: Data from participants in the American Cancer Society (ACS) Cancer Prevention Study-3 cohort were used for this analysis. NNS intake was estimated using self-reported consumption of NNS-containing beverages, packets, and yogurt from a validated food frequency questionnaire. Participants were categorized into non-consumers, <1 serving, 1-<2 servings and ≥2 servings per day. Diet quality was assessed using the ACS Diet Score (2020) and Healthy Eating Index (HEI-2015). ANOVA was used to compare diet quality scores across NNS consumption groups, and multivariable linear regression was used to examine associations between NNS consumption and diet quality. Multivariable logistic regression was used to evaluate odds of low diet quality across NNS consumption groups.
    RESULTS: Data from 163,679 participants (median age 53 years (IQR 45-60), 78.9% women, mean NNS intake 1.0 ± 1.5 servings per day, mean HEI-2015 score 75.4 ± 10.2) were included. NNS consumers had lower diet quality for ACS Diet Score (6.8 ± 0.03 among non-consumers versus 6.5 ± 0.03, 6.3 ± 0.03 and 6.1± 0.03 for consumers of <1 serving, 1-<2 servings, and ≥2 servings of NNS per day, respectively, p-trend <0.0001) and HEI-2015 (76.3 ± 0.1 among non-consumers versus 76.7 ± 0.1, 75.6 ± 0.2, and 72.7± 0.2 for consumers of <1 serving, 1-<2 servings, and ≥2 servings of NNS per day, respectively, p-trend <0.0001). Odds of low diet quality were higher among NNS consumers and were higher with higher NNS consumption (3%, 17%, and 43% higher odds of low diet quality among those who consumed <1 serving, 1-<2 servings and ≥2 servings of NNS beverages per day).
    CONCLUSIONS: NNS consumers had lower diet quality in a large cohort of U.S. adults.
    Keywords:  artificial sweeteners; beverages; cancer prevention; diet soda; low-calorie sweeteners; non-nutritive sweeteners; nutrition; obesity; sugar substitutes; weight
    DOI:  https://doi.org/10.1016/j.ajcnut.2024.11.023
  25. Phenomics. 2024 Aug;4(4): 313-326
      Many laboratories have demonstrated that the ketogenic diet (KD) can lead to weight loss and reduced fasting glucose levels, while also increasing total serum cholesterol levels. However, it's worth noting that the specific outcomes induced by KD can vary across different research settings. Certain studies have indicated that environmental factors, such as housing conditions and the acidity of drinking water, can influence physiological parameters and gut microbes in mice. Thus, our current study aimed to investigate whether differences in housing conditions and pH levels of drinking water contribute to variations in KD-induced phenotypes and gut microbes. Our findings revealed that mice housed in conventional (CV) conditions experienced more significant weight loss, lower fasting blood glucose levels, and a greater elevation of blood cholesterol levels compared to those in the specific pathogen-free (SPF) condition. Additionally, similar differences were observed when comparing mice fed with non-acidified water versus acidified water. Furthermore, we analyzed cecum content samples using 16S rRNA sequencing to assess gut microbial composition and found that the tested environmental variables also had an impact on the gut microbial composition of KD-fed mice, which was correlated with their phenotypic alterations. In summary, both housing conditions and the pH of drinking water were identified as crucial environmental factors that influenced KD-induced changes in metabolic phenotypes and gut microbes. Our study emphasizes the importance of considering these factors in animal studies related to KD and gut microbes, as well as in other types of animal research.
    Supplementary Information: The online version contains supplementary material available at 10.1007/s43657-024-00161-1.
    Keywords:  Environmental factors; Gut microbes; Ketogenic diet; Metabolic phenotypes
    DOI:  https://doi.org/10.1007/s43657-024-00161-1
  26. Antioxid Redox Signal. 2024 Nov;41(13-15): 927-956
      Significance: Dimeric nicotinamide nucleotide transhydrogenase (NNT) is embedded in the mitochondrial inner membrane and couples the conversion of NADP+/NADH into NADPH/NAD+ to mitochondrial matrix proton influx. NNT was implied in various cancers, but its physiological role and regulation still remain incompletely understood. Recent Advances: NNT function was analyzed by studying: (1) NNT gene mutations in human (adrenal) glucocorticoid deficiency 4 (GCCD4), (2) Nnt gene mutation in C57BL/6J mice, and (3) the effect of NNT knockdown/overexpression in (cancer) cells. In these three models, altered NNT function induced both common and differential aberrations. Critical Issues: Information on NNT protein expression in GCCD4 patients is still scarce. Moreover, NNT expression levels are tissue-specific in humans and mice and the functional consequences of NNT deficiency strongly depend on experimental conditions. In addition, data from intact cells and isolated mitochondria are often unsuited for direct comparison. This prevents a proper understanding of NNT-linked (patho)physiology in GCCD4 patients, C57BL/6J mice, and cancer (cell) models, which complicates translational comparison. Future Directions: Development of mice with conditional NNT deletion, cell-reprogramming-based adrenal (organoid) models harboring specific NNT mutations, and/or NNT-specific chemical inhibitors/activators would be useful. Moreover, live-cell analysis of NNT substrate levels and mitochondrial/cellular functioning with fluorescent reporter molecules might provide novel insights into the conditions under which NNT is active and how this activity links to other metabolic and signaling pathways. This would also allow a better dissection of local signaling and/or compartment-specific (i.e., mitochondrial matrix, cytosol, nucleus) effects of NNT (dys)function in a cellular context. Antioxid. Redox Signal. 41, 927-956.
    Keywords:  NNT; bioenergetics; cancer; experimental models; mitochondria; redox homeostasis
    DOI:  https://doi.org/10.1089/ars.2024.0694
  27. Biosystems. 2024 Nov 22. pii: S0303-2647(24)00261-2. [Epub ahead of print]247 105376
      Biophysical, developmental and systems-biology considerations enable deeper understanding why cancer is life threatening despite intensive research. Here we use two metaphors. Both conceive the cell genome and the encoded molecular system as an interacting gene regulatory network (GRN). According to Waddington's epigenetic (quasi-potential)-landscape, an instrumental tool in ontogenetics, individual interaction patterns ( = expression profiles) within this GRN represent possible cell states with different stabilities. Network interactions with low stability are represented on peaks. Unstable interactions strive towards regions with higher stability located at lower altitude in valleys termed attractors that correspond to stable cell phenotypes. Cancer cells are seen as GRNs adopting aberrant semi-stable attractor states (cancer attractor). In the second metaphor, Wright's phylogenetic fitness (adaptive) landscape, each genome ( = GRN) is assigned a specific position in the landscape according to its structure and reproductive fitness in the specific environment. High elevation signifies high fitness and low altitude low fitness. Selection ensures that mutant GRNs evolve and move from valleys to peaks. The genetic flexibility is highlighted in the fitness landscape, while non-genetic flexibility is captured in the quasi-potential landscape. These models resolve several inconsistencies that have puzzled cancer researchers, such as the fact that phenotypes generated by non-genetic mechanisms coexist in a single tumor with phenotypes caused by mutations and they mitigate conflicts between cancer theories that claim cancer is caused by mutation (somatic mutation theory) or by disruption of tissue architecture (tissue organization field theory). Nevertheless, spontaneous mutations play key roles in cancer. Remarkable, fundamental natural laws such as the second law of thermodynamics and quantum mechanics state that mutations are inevitable events. The good side of this is that without mutational variability in DNA, evolutionary development would not have occurred, but its bad side is that the occurrence of cancer is essentially inevitable. In summary, both landscapes together fully describe the behavior of cancer under normal and stressful conditions such as chemotherapy. Thus, the landscapes-attractor model fully describes cancer cell behavior and offers new perspectives for future treatment.
    Keywords:  Cancer attractor; Entropy; Epigenetic landscape; Fitness landscape; Mutation; Quantum biology
    DOI:  https://doi.org/10.1016/j.biosystems.2024.105376
  28. Int J Pharm. 2024 Nov 22. pii: S0378-5173(24)01223-7. [Epub ahead of print] 124989
      The backbone of induction therapy in acute myeloid leukaemia (AML) is to use an anthracycline in combination with cytarabine. Despite recent advances in AML therapy, this treatment remains the standard, and it has remained unchanged for decades. There are few curative options for patients unfit for this treatment. The anti-protozoal agent emetine improves efficacy of anthracycline treatment towards AML in vitro and in vivo but the effect is more potent when emetine is administered 30 min after anthracyclines. To delay the onset of protein synthesis inhibition we produced a novel inactive emetine prodrug and co-encapsulated this with the anthracycline daunorubicin (DNR) in liposomes. Nanoencapsulation protects the prodrug from degradation in the blood and ensure simultaneous delivery of both drugs to cancer cells. The prodrug concept will delay the onset of action of emetine relative to DNR. In AML cells, the combination of DNR and the emetine-prodrug in liposomes increased cytotoxicity compared to liposomes with DNR and native emetine. Liposomes loaded with the emetine prodrug did not show increased toxicity towards non-cancerous cell lines and zebrafish larvae. In patients, a liposomal formulation such as that presented herein could allow for a reduced DNR dose without compromising efficacy, thereby reducing toxic side effects and enabling improved therapy for patients not fit for current treatment options.
    Keywords:  Acute myeloid leukaemia; Daunorubicin; Drug repurposing; Emetine; Liposomes
    DOI:  https://doi.org/10.1016/j.ijpharm.2024.124989
  29. Mol Brain. 2024 Nov 27. 17(1): 87
      Recessive loss-of-function mutations in the mitochondrial enzyme Glutamate Pyruvate Transaminase 2 (GPT2) cause intellectual disability in children. Given this cognitive disorder, and because glutamate metabolism is tightly regulated to sustain excitatory neurotransmission, here we investigate the role of GPT2 in synaptic function. GPT2 catalyzes a reversible reaction interconverting glutamate and pyruvate with alanine and alpha-ketoglutarate, a TCA cycle intermediate; thereby, GPT2 may play an important role in linking mitochondrial tricarboxylic acid (TCA) cycle with synaptic transmission. In mouse brain, we find that GPT2 is enriched in mitochondria of synaptosomes (isolated synaptic terminals). Loss of Gpt2 in mouse appears to lead to reprogramming of glutamate and glutamine metabolism, and to decreased glutamatergic synaptic transmission. Whole-cell patch-clamp recordings in pyramidal neurons of CA1 hippocampal slices from Gpt2-null mice reveal decreased excitatory post-synaptic currents (mEPSCs) without changes in mEPSC frequency, or importantly, changes in inhibitory post-synaptic currents (mIPSCs). Additional evidence of defective glutamate release included reduced levels of glutamate released from Gpt2-null synaptosomes measured biochemically. Glutamate release from synaptosomes was rescued to wild-type levels by alpha-ketoglutarate supplementation. Additionally, we observed evidence of altered metabolism in isolated Gpt2-null synaptosomes: decreased TCA cycle intermediates, and increased glutamate dehydrogenase activity. Notably, alterations in the TCA cycle and the glutamine pool were alleviated by alpha-ketoglutarate supplementation. In conclusion, our data support a model whereby GPT2 mitochondrial activity may contribute to glutamate availability in pre-synaptic terminals, thereby highlighting potential interactions between pre-synaptic mitochondrial metabolism and synaptic transmission.
    Keywords:  Cognitive development; Disease; GPT2; Glutamate; Intellectual disability; Neurometabolic; Neurometabolism; Synapse; TCA cycle
    DOI:  https://doi.org/10.1186/s13041-024-01154-x
  30. Genes (Basel). 2024 Oct 28. pii: 1383. [Epub ahead of print]15(11):
      Background: Although BRAF V600E mutations are common in solid tumors and select hematologic neoplasms, they are reported less frequently in myeloid malignancies. Of the cases of BRAF V600E-mutant acute myeloid leukemia (AML) that have been described, most display monocytic morphology and concurrent KMT2A rearrangement. Strikingly, all cases have been associated with poor survival. Case Presentation: Here, we report two cases of AML, one diagnosed in an elderly male with metastatic lung adenocarcinoma and hepatocellular carcinoma and the other diagnosed in a young boy previously treated for B-cell acute lymphoblastic leukemia. Peripheral blood NGS revealed oncogenic mutations in BRAF p.V600E (VAF = 33%), TET2 p.M508Cfs*25 (VAF = 48%), TET2 p.C211* (VAF = 49%), ZRSR2 p.R295* (VAF = 71%), BRAF p.N581S (VAF = 6%), and EZH2 c.118-2A>G, p.? (VAF = 4%) in case 1 and BRAF p.V600E (VAF = 1%) and KRAS p.G12A (VAF = 28%) in case 2. Cytogenetic workup revealed a complex karyotype in case 1 and an abnormal karyotype with non-clonal aberrations and KMT2A (MLL) rearrangement in case 2. Morphologically, both patients were found to have AML with monocytic features. The post-mortem examination of case 2 also revealed extensive solid organ infiltration, consistent with a monocytic leukemia. Both patients died within days of diagnosis, demonstrating the lethality of this molecular subgroup of AML. Conclusions: Our cases add to the literature, highlighting the poor prognosis of patients diagnosed with BRAF-mutant AML. Although it is uncertain whether the complex karyotype and somatic mutations observed in case 1 and KMT2A rearrangement and variants identified in case 2 may have either independently or cooperatively conferred a poor prognosis, we contend that additional comprehensive studies are needed to further understand the pathophysiology and prognosis of BRAF mutations in AML. We further posit whether patients with BRAF V600E-mutant AML may benefit from the combined use of BRAF inhibitors and/or RAS-pathway-targeting regimens, which are currently FDA-approved for the treatment of BRAF V600-mutant solid tumors and BRAF-mutant histiocytic neoplasms.
    Keywords:  AML; Acute myeloid leukemia; BRAF V600E
    DOI:  https://doi.org/10.3390/genes15111383
  31. Nutrients. 2024 Nov 08. pii: 3828. [Epub ahead of print]16(22):
      Succinic acid plays a crucial role as an essential intermediate in the mitochondrial tricarboxylic acid cycle in mitochondria. In recent years, growing evidence has supported the the important role of succinic acid in fat metabolism. Therefore, we aimed to investigate the effects of succinic acid on adipose tissue metabolism and insulin sensitivity in high-fat diet (HFD)-induced obese mice and try to explore its potential mechanism. We found that the addition of succinic acid (40 mM) to drinking water inhibited the hypertrophy of inguinal white adipose tissue (iWAT) in HFD-induced mice. Furthermore, succinic acid supplementation enhanced insulin sensitivity and improved their glucose tolerance in obese mice. Interestingly, succinic acid supplementation improved lipid metabolism in HFD-fed mice, as shown by decreased serum levels of TG, TC, LDL-C, and increased HDL-C. In addition, succinic acid supplementation increased the expression of browning markers and mitochondria-related genes in iWAT. Further studies showed that the addition of succinic acid to drinking water promotes the browning of iWAT by activating the PI3K-AKT/MAPK signaling pathway. These results suggest that succinic acid has the potential to be used as an effective component for dietary intervention and may, therefore, play an important role in ameliorating and preventing obesity and associated metabolic diseases caused by HFD.
    Keywords:  fat browning; insulin resistance; lipid metabolism; obesity; succinic acid
    DOI:  https://doi.org/10.3390/nu16223828
  32. Biofactors. 2024 Nov 28.
      The rising incidence of colorectal cancer (CRC) poses significant healthcare challenges. This study explored the therapeutic potential of combined curcumin (CUR) and metformin (MET) treatment in CRC models. Our findings indicate that the combination treatment (COMB) effectively downregulates the expression of divalent metal transporter-1 (DMT-1), leading to a reduction in cell proliferation aligned with suppression of the pAKT/mTOR/Cyclin D1 signaling pathway. The COMB increased reactive oxygen species (ROS) production, triggering activation of the NRF2/KEAP1 pathway. This pathway elicits an antioxidant response to manage oxidative stress in CRC cell lines. Interestingly, the response of NRF2 varied between CT26 and HCT116 cells. Moreover, our study highlights the induction of apoptosis and autophagy, as evidenced by upregulations in Bax/Bcl-2 ratios and autophagy-related protein expressions. Notably, the COMB promoted lipid peroxidation and downregulated xCT levels, suggesting the induction of ferroptosis. Ferroptosis has been shown to activate autophagy, which helps eliminate cells potentially damaged by the increased oxidative stress. Furthermore, the COMB effectively diminished the migratory ability of CRC cells. In vivo experiments using CRC-bearing mouse models, the results confirmed the anti-tumor efficacy of the COMB, leading to substantial inhibition of tumor growth without inducing general toxicity. In conclusion, our study suggests that combining CUR with MET holds promise as a potential option for CRC treatment, with critical mechanisms likely involving ROS elevation, autophagy, and ferroptosis.
    Keywords:  DMT1; ROS; autophagy; colorectal cancer; curcumin; ferroptosis; metformin
    DOI:  https://doi.org/10.1002/biof.2137