bims-medica 2024-04-14 papers

bims-medica

Biomed News

on Metabolism and diet in cancer

Issue of 2024–04–14
thirty-six papers selected by
Brett Chrest, East Carolina University

Inhibition of Carbohydrate Metabolism Potentiated by the Therapeutic Effects of Oxidative Phosphorylation Inhibitors in Colon Cancer Cells.
Neuroprotective effects of lactate and ketone bodies in acute brain injury.
Exploiting pancreatic cancer metabolism: challenges and opportunities.
Determination of fatty acid uptake and desaturase activity in mammalian cells by NMR-based stable isotope tracing.
The troglitazone derivative EP13 disrupts energy metabolism through respiratory chain complex I inhibition in breast cancer cells and potentiates the antiproliferative effect of glycolysis inhibitntriors.
Sex-Dependent Metabolic Effects in Diet-Induced Obese Rats following Intermittent Fasting Compared with Continuous Food Restriction.
Visualizing subcellular changes in the NAD(H) pool size versus redox state using fluorescence lifetime imaging microscopy of NADH.
Mechanical regulation of mitochondrial morphodynamics in cancer cells by extracellular microenvironment.
Ketogenic diet alters the epigenetic and immune landscape of prostate cancer to overcome resistance to immune checkpoint blockade therapy.
Management of isocitrate dehydrogenase 1/2 mutated acute myeloid leukemia.
Ketogenic metabolic therapy in conjunction with standard treatment for glioblastoma: A case report.
Purine salvage promotes treatment resistance in H3K27M-mutant diffuse midline glioma.
DRP1 inhibition-mediated mitochondrial elongation abolishes cancer stemness, enhances glutaminolysis, and drives ferroptosis in oral squamous cell carcinoma.
Machine learning-based 3D segmentation of mitochondria in polarized epithelial cells.
An Innovative Mitochondrial-targeted Gene Therapy for Cancer Treatment.
Inhibition of pyruvate dehydrogenase accelerates anaerobic glycolysis under postmortem simulating conditions.
Rescue of Methionine Dependence by Cobalamin in a Human Colorectal Cancer Cell Line.
Cytosolic RNA binding of the mitochondrial TCA cycle enzyme malate dehydrogenase (MDH2).
Glioblastoma modeling with 3D organoids: progress and challenges.
Epithelial and mesenchymal phenotypes determine the dynamics of circulating breast tumor cells in microfluidic capillaries under chemotherapy-induced stress.
Venetoclax Combination Treatment of Acute Myeloid Leukemia in Adolescents and Young Adult Patients.
LDHB contributes to the regulation of lactate levels and basal insulin secretion in human pancreatic β cells.
Impact of sustained calorie restriction and weight cycling on body composition in high-fat diet-fed male and female C57BL/6J mice.
Human mitochondrial glutathione transferases: Kinetic parameters and accommodation of a mitochondria-targeting group in substrates.
Role of SGLT2 Inhibitors, DPP-4 Inhibitors, and Metformin in Pancreatic Cancer Prevention.
Hepatic ketone body regulation of renal gluconeogenesis.
Metabologenomic characterization uncovers a clinically aggressive IDH mutant glioma subtype.
Fasting upregulates the monocarboxylate transporter MCT1 at the rat blood-brain barrier through PPAR δ activation.
Altered lipid metabolism in APC-driven colorectal cancer: the potential for therapeutic intervention.
A lipid atlas of human and mouse immune cells provides insights into ferroptosis susceptibility.
Modeling of brain efflux: Constraints of brain surfaces.
Fasting and fasting-mimicking conditions in the cancer immunotherapy era.
β cell acetate production and release are negligible.
Examining the Role of Nutrition in Cancer Survivorship and Female Fertility: A Narrative Review.
Nutritional Quality Implications: Exploring the Impact of a Fatty Acid-Rich Diet on Central Nervous System Development.
Derivative survival analyses: Analysis methods to derive survival outcomes for the remainder patient cohort without individual patient data.

Cancers (Basel). 2024 Apr 02. pii: 1399. [Epub ahead of print]16(7):

Inhibition of Carbohydrate Metabolism Potentiated by the Therapeutic Effects of Oxidative Phosphorylation Inhibitors in Colon Cancer Cells.

Lichao Guo, Baochen Zhang, Wen Zhang, Yanqi Xie, Xi Chen, Xueke Sun, David S Watt, Chunming Liu, H Peter Spielmann, Xifu Liu.

  Cancer cells undergo a significant level of "metabolic reprogramming" or "remodeling" to ensure an adequate supply of ATP and "building blocks" for cell survival and to facilitate accelerated proliferation. Cancer cells preferentially use glycolysis for ATP production (the Warburg effect); however, cancer cells, including colorectal cancer (CRC) cells, also depend on oxidative phosphorylation (OXPHOS) for ATP production, a finding that suggests that both glycolysis and OXPHOS play significant roles in facilitating cancer progression and proliferation. Our prior studies identified a semisynthetic isoflavonoid, DBI-1, that served as an AMPK activator targeting mitochondrial complex I. Furthermore, DBI-1 and a glucose transporter 1 (GLUT1) inhibitor, BAY-876, synergistically inhibited CRC cell growth in vitro and in vivo. We now report a study of the structure-activity relationships (SARs) in the isoflavonoid family in which we identified a new DBI-1 analog, namely, DBI-2, with promising properties. Here, we aimed to explore the antitumor mechanisms of DBIs and to develop new combination strategies by targeting both glycolysis and OXPHOS. We identified DBI-2 as a novel AMPK activator using an AMPK phosphorylation assay as a readout. DBI-2 inhibited mitochondrial complex I in the Seahorse assays. We performed proliferation and Western blotting assays and conducted studies of apoptosis, necrosis, and autophagy to corroborate the synergistic effects of DBI-2 and BAY-876 on CRC cells in vitro. We hypothesized that restricting the carbohydrate uptake with a KD would mimic the effects of GLUT1 inhibitors, and we found that a ketogenic diet significantly enhanced the therapeutic efficacy of DBI-2 in CRC xenograft mouse models, an outcome that suggested a potentially new approach for combination cancer therapy.

Keywords:  OXPHOS; colorectal cancer; glycolysis; isoflavonoid; ketogenic diet; mitochondria complex I

DOI:  https://doi.org/10.3390/cancers16071399
J Cereb Blood Flow Metab. 2024 Apr 11. 271678X241245486

Neuroprotective effects of lactate and ketone bodies in acute brain injury.

Guillaume Plourde, Hélène Roumes, Laurent Suissa, Lorenz Hirt, Émilie Doche, Luc Pellerin, Anne-Karine Bouzier-Sore, Hervé Quintard.

  The goal of neurocritical care is to prevent and reverse the pathologic cascades of secondary brain injury by optimizing cerebral blood flow, oxygen supply and substrate delivery. While glucose is an essential energetic substrate for the brain, we frequently observe a strong decrease in glucose delivery and/or a glucose metabolic dysregulation following acute brain injury. In parallel, during the last decades, lactate and ketone bodies have been identified as potential alternative fuels to provide energy to the brain, both under physiological conditions and in case of glucose shortage. They are now viewed as integral parts of brain metabolism. In addition to their energetic role, experimental evidence also supports their neuroprotective properties after acute brain injury, regulating in particular intracranial pressure control, decreasing ischemic volume, and leading to an improvement in cognitive functions as well as survival. In this review, we present preclinical and clinical evidence exploring the mechanisms underlying their neuroprotective effects and identify research priorities for promoting lactate and ketone bodies use in brain injury.

Keywords:  Alternative brain fuels; TBI; brain metabolism; hypoxia; ketone bodies; lactate; neuroprotection; stroke

DOI:  https://doi.org/10.1177/0271678X241245486
Trends Mol Med. 2024 Apr 10. pii: S1471-4914(24)00063-7. [Epub ahead of print]

Exploiting pancreatic cancer metabolism: challenges and opportunities.

Maria Chiara De Santis, B Bockorny, E Hirsch, P Cappello, M Martini.

  Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive form of pancreatic cancer, known for its challenging diagnosis and limited treatment options. The focus on metabolic reprogramming as a key factor in tumor initiation, progression, and therapy resistance has gained prominence. In this review we focus on the impact of metabolic changes on the interplay among stromal, immune, and tumor cells, as glutamine and branched-chain amino acids (BCAAs) emerge as pivotal players in modulating immune cell functions and tumor growth. We also discuss ongoing clinical trials that explore metabolic modulation for PDAC, targeting mitochondrial metabolism, asparagine and glutamine addiction, and autophagy inhibition. Overcoming challenges in understanding nutrient effects on immune-stromal-tumor interactions holds promise for innovative therapeutic strategies.

Keywords:  heterogeneity; immunotherapy; metabolic reprogramming; mitochondrial metabolism; pancreatic cancer; tumor microenvironment

DOI:  https://doi.org/10.1016/j.molmed.2024.03.008
Anal Chim Acta. 2024 May 15. pii: S0003-2670(24)00312-X. [Epub ahead of print]1303 342511

Determination of fatty acid uptake and desaturase activity in mammalian cells by NMR-based stable isotope tracing.

Penghui Lin, James Sledziona, Kubra B Akkaya-Colak, Maria M Mihaylova, Andrew N Lane.

   BACKGROUND: Mammalian cells both import exogenous fatty acids and synthesize them de novo. Palmitate, the end product of fatty acid synthase (FASN) is a substrate for stearoyl-CoA desaturases (Δ-9 desaturases) that introduce a single double bond into fatty acyl-CoA substrates such as palmitoyl-CoA and stearoyl-CoA. This process is particularly upregulated in lipogenic tissues and cancer cells. Tracer methodology is needed to determine uptake versus de novo synthesis of lipids and subsequent chain elongation and desaturation. Here we describe an NMR method to determine the uptake of 13C-palmitate from the medium into HCT116 human colorectal cancer cells, and the subsequent desaturation and incorporation into complex lipids.
RESULTS: Exogenous 13C16-palmitate was absorbed from the medium by HCT116 cells and incorporated primarily into complex glycerol lipids. Desaturase activity was determined from the quantification of double bonds in acyl chains, which was greatly reduced by ablation of the major desaturase SCD1.
SIGNIFICANCE: The NMR approach requires minimal sample preparation, is non-destructive, and provides direct information about the level of saturation and incorporation of fatty acids into complex lipids.

Keywords:  Desaturase activity; Fatty acid uptake; NMR

DOI:  https://doi.org/10.1016/j.aca.2024.342511
Cancer Cell Int. 2024 Apr 10. 24(1): 132

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

Claire Muller, Victorine Lacroix-Malgras, Jérôme Kluza, William Laine, Yonca Güler, Frédéric Bost, Michel Boisbrun, Sabine Mazerbourg, Stéphane Flament.

   BACKGROUND: The metabolism of cancer cells generally differs from that of normal cells. Indeed, most cancer cells have a high rate of glycolysis, even at normal oxygen concentrations. These metabolic properties can potentially be exploited for therapeutic intervention. In this context, we have developed troglitazone derivatives to treat hormone-sensitive and triple-negative breast cancers, which currently lack therapeutic targets, have an aggressive phenotype, and often have a worse prognosis than other subtypes. Here, we studied the metabolic impact of the EP13 compound, a desulfured derivative of Δ2-troglitazone that we synthetized and is more potent than its parent compounds.
METHODS: EP13 was tested on two triple-negative breast cancer cell lines, MDA-MB-231 and Hs578T, and on the luminal cell line MCF-7. The oxygen consumption rate (OCR) of the treated cell lines, Hs578T mammospheres and isolated mitochondria was measured using the XFe24 Seahorse analyser. ROS production was quantified using the MitoSOX fluorescent probe. Glycolytic activity was evaluated through measurement of the extracellular acidification rate (ECAR), glucose consumption and lactate production in extracellular medium. The synergistic effect of EP13 with glycolysis inhibitors (oxamate and 2-deoxyglucose) on cell cytotoxicity was established using the Chou-Talalay method.
RESULTS: After exposure to EP13, we observed a decrease in the mitochondrial oxygen consumption rate in MCF7, MDA-MB-231 and Hs578T cells. EP13 also modified the maximal OCR of Hs578T spheroids. EP13 reduced the OCR through inhibition of respiratory chain complex I. After 24 h, ATP levels in EP13-treated cells were not altered compared with those in untreated cells, suggesting compensation by glycolysis activity, as shown by the increase in ECAR, the glucose consumption and lactate production. Finally, we performed co-treatments with EP13 and glycolysis inhibitors (oxamate and 2-DG) and observed that EP13 potentiated their cytotoxic effects.
CONCLUSION: This study demonstrates that EP13 inhibits OXPHOS in breast cancer cells and potentiates the effect of glycolysis inhibitors.

Keywords:  Breast cancer; Energy metabolism; Glycolysis; Mitochondria; Oxygen consumption; Thiazolidinediones; Troglitazone

DOI:  https://doi.org/10.1186/s12935-024-03319-z
Nutrients. 2024 Mar 29. pii: 1009. [Epub ahead of print]16(7):

Sex-Dependent Metabolic Effects in Diet-Induced Obese Rats following Intermittent Fasting Compared with Continuous Food Restriction.

Laia Bosch de Basea, Marina Boguñà, Alicia Sánchez, Montserrat Esteve, Mar Grasa, Maria Del Mar Romero.

  Recently, intermittent fasting has gained relevance as a strategy to lose weight and improve health as an alternative to continuous caloric restriction. However, the metabolic impact and the sex-related differences are not fully understood. The study aimed to compare the response to a continuous or intermittent caloric restriction in male and female rats following a previous induction of obesity through a cafeteria diet by assessing changes in body weight, energy intake, metabolic parameters, and gene expression in liver hepatic and adipose tissue. The continuous restriction reduced the energy available by 30% and the intermittent restriction consisted of a 75% energy reduction on two non-consecutive days per week. The interventions reduced body weight and body fat in both sexes, but the loss of WAT in females was more marked in both models of caloric restriction, continuous and intermittent. Both caloric restrictions improved insulin sensitivity, but more markedly in females, which showed a more pronounced decrease in HOMA-IR score and an upregulation of hepatic IRS2 and Sirt1 gene expression that was not observed in males. These findings suggest the fact that females are more sensitive than males to reduced caloric content in the diet.

Keywords:  cafeteria diet; caloric restriction; insulin resistance; intermittent fasting

DOI:  https://doi.org/10.3390/nu16071009
Commun Biol. 2024 Apr 09. 7(1): 428

Visualizing subcellular changes in the NAD(H) pool size versus redox state using fluorescence lifetime imaging microscopy of NADH.

Angela Song, Nicole Zhao, Diana C Hilpert, Caroline Perry, Joseph A Baur, Douglas C Wallace, Patrick M Schaefer.

NADH autofluorescence imaging is a promising approach for visualizing energy metabolism at the single-cell level. However, it is sensitive to the redox ratio and the total NAD(H) amount, which can change independently from each other, for example with aging. Here, we evaluate the potential of fluorescence lifetime imaging microscopy (FLIM) of NADH to differentiate between these modalities.We perform targeted modifications of the NAD(H) pool size and ratio in cells and mice and assess the impact on NADH FLIM. We show that NADH FLIM is sensitive to NAD(H) pool size, mimicking the effect of redox alterations. However, individual components of the fluorescence lifetime are differently impacted by redox versus pool size changes, allowing us to distinguish both modalities using only FLIM. Our results emphasize NADH FLIM's potential for evaluating cellular metabolism and relative NAD(H) levels with high spatial resolution, providing a crucial tool for our understanding of aging and metabolism.

DOI: https://doi.org/10.1038/s42003-024-06123-7
Biomater Biosyst. 2024 Jun;14 100093

Mechanical regulation of mitochondrial morphodynamics in cancer cells by extracellular microenvironment.

Mariia Lunova, Milan Jirsa, Alexandr Dejneka, Gareth John Sullivan, Oleg Lunov.

  Recently, it has been recognized that physical abnormalities (e.g. elevated solid stress, elevated interstitial fluid pressure, increased stiffness) are associated with tumor progression and development. Additionally, these mechanical forces originating from tumor cell environment through mechanotransduction pathways can affect metabolism. On the other hand, mitochondria are well-known as bioenergetic, biosynthetic, and signaling organelles crucial for sensing stress and facilitating cellular adaptation to the environment and physical stimuli. Disruptions in mitochondrial dynamics and function have been found to play a role in the initiation and advancement of cancer. Consequently, it is logical to hypothesize that mitochondria dynamics subjected to physical cues may play a pivotal role in mediating tumorigenesis. Recently mitochondrial biogenesis and turnover, fission and fusion dynamics was linked to mechanotransduction in cancer. However, how cancer cell mechanics and mitochondria functions are connected, still remain poorly understood. Here, we discuss recent studies that link mechanical stimuli exerted by the tumor cell environment and mitochondria dynamics and functions. This interplay between mechanics and mitochondria functions may shed light on how mitochondria regulate tumorigenesis.

Keywords:  Cancer; Mechanotransduction; Mitochondria; Mitochondrial dynamics; Tumor metabolism

DOI:  https://doi.org/10.1016/j.bbiosy.2024.100093
Cancer Res. 2024 Apr 08.

Ketogenic diet alters the epigenetic and immune landscape of prostate cancer to overcome resistance to immune checkpoint blockade therapy.

Sean Murphy, Sharif Rahmy, Dailin Gan, Guoqiang Liu, Yini Zhu, Maxim Manyak, Loan Duong, Jianping He, James H Schofield, Zachary T Schafer, Jun Li, Xuemin Lu, Xin Lu.

Resistance to immune checkpoint blockade (ICB) therapy represents a formidable clinical challenge limiting the efficacy of immunotherapy. In particular, prostate cancer (PCa) poses a challenge for ICB therapy due to its immunosuppressive features. A ketogenic diet (KD) has been reported to enhance response to ICB therapy in some other cancer models. However, adverse effects associated with continuous KD were also observed, demanding better mechanistic understanding and optimized regimens for using KD as an immunotherapy sensitizer. In this study, we established a series of ICB-resistant PCa cell lines and developed a highly effective strategy of combining anti-PD1 and anti-CTLA4 antibodies with histone deacetylase inhibitor (HDACi) vorinostat, a cyclic ketogenic diet (CKD), or dietary supplementation of the ketone body β-hydroxybutyrate (BHB), which is an endogenous HDACi. CKD and BHB supplementation each delayed PCa tumor growth as monotherapy, and both BHB and adaptive immunity were required for the anti-tumor activity of CKD. Single-cell transcriptomic and proteomic profiling revealed that HDACi and ketogenesis enhanced ICB efficacy through both cancer cell-intrinsic mechanisms, including upregulation of MHC class I molecules, and -extrinsic mechanisms, such as CD8+ T cell chemoattraction, M1/M2 macrophage rebalancing, monocyte differentiation toward antigen presenting cells, and diminished neutrophil infiltration. Overall, these findings illuminate a potential clinical path of using HDACi and optimized KD regimens to enhance ICB therapy for PCa.

DOI: https://doi.org/10.1158/0008-5472.CAN-23-2742
Leukemia. 2024 Apr 10.

Management of isocitrate dehydrogenase 1/2 mutated acute myeloid leukemia.

Harry Fruchtman, Zachary M Avigan, Julian A Waksal, Nicole Brennan, John O Mascarenhas.

The emergence of next generation sequencing and widespread use of mutational profiling in acute myeloid leukemia (AML) has broadened our understanding of the heterogeneous molecular basis of the disease. Since genetic sequencing has become a standard practice, several driver mutations have been identified. Accordingly, novel targeted therapeutic agents have been developed and are now approved for the treatment of subsets of patients that carry mutations in FLT3, IDH1, and IDH2 [1, 2]. The emergence of these novel agents in AML offers patients a new modality of therapy, and shifts treatment paradigms toward individualized medicine. In this review, we outline the role of IDH mutations in malignant transformation, focus in on a novel group of targeted therapeutic agents directed toward IDH1- and IDH2-mutant AML, and explore their impact on prognosis in patients with AML.

DOI: https://doi.org/10.1038/s41375-024-02246-2
Oncol Lett. 2024 May;27(5): 230

Ketogenic metabolic therapy in conjunction with standard treatment for glioblastoma: A case report.

Matthew C L Phillips, Ziad Thotathil, Prashanth Hari Dass, Fouzia Ziad, Ben G Moon.

  Glioblastoma (GBM) is the most common primary malignant brain tumour in adults. The standard of care consists of surgical resection and concurrent chemoradiation, followed by adjuvant temozolomide chemotherapy. This protocol is associated with a median survival of 12-15 months, and <5% of patients survive >3 years. Ketogenic metabolic therapy (KMT) targets cancer cell metabolism by restricting glucose availability and evoking differential stress resistance and sensitization, which may augment the standard treatments and lead to therapeutic benefit. The present study reports the case of a 64-year-old woman with isocitrate dehydrogenase (IDH)-wildtype GBM who pursued the standard treatment protocol in conjunction with an intensive, multimodal KMT program for 3 years. The KMT program consisted of a series of prolonged (7-day, fluid-only) fasts, which were specifically timed to maximize the tolerability and efficacy of the standard treatments, combined with a time-restricted ketogenic diet on all other days. During the first and second treatment years the patient sustained a glucose ketone index (GKI) of 1.65 and 2.02, respectively, which coincided with complete clinical improvement, a healthy body-mass index and a high quality of life, with no visible progressive tumour detected on imaging at the end of the second year. In the setting of the death of an immediate family member leading to increased life stress, slightly relaxed KMT adherence, and a higher GKI of 3.20, slow cancer progression occurred during the third year. The adverse effects attributed to KMT were mild. Despite the limitations of this case report, it highlights the feasibility of implementing the standard treatment protocol for GBM in conjunction with an intensive, long-term, multimodal and specifically timed KMT program, the potential therapeutic efficacy of which may depend upon achieving as low a GKI as possible.

Keywords:  cancer; fasting; glioblastoma; ketogenic diet; metabolic therapy

DOI:  https://doi.org/10.3892/ol.2024.14363
Cancer Metab. 2024 Apr 09. 12(1): 11

Purine salvage promotes treatment resistance in H3K27M-mutant diffuse midline glioma.

Erik R Peterson, Peter Sajjakulnukit, Andrew J Scott, Caleb Heaslip, Anthony Andren, Kari Wilder-Romans, Weihua Zhou, Sravya Palavalasa, Navyateja Korimerla, Angelica Lin, Alexandra O'Brien, Ayesha Kothari, Zitong Zhao, Li Zhang, Meredith A Morgan, Sriram Venneti, Carl Koschmann, Nada Jabado, Costas A Lyssiotis, Maria G Castro, Daniel R Wahl.

   BACKGROUND: Diffuse midline gliomas (DMG), including diffuse intrinsic pontine gliomas (DIPGs), are a fatal form of brain cancer. These tumors often carry a driver mutation on histone H3 converting lysine 27 to methionine (H3K27M). DMG-H3K27M are characterized by altered metabolism and resistance to standard of care radiation (RT) but how the H3K27M mediates the metabolic response to radiation and consequent treatment resistance is uncertain.
METHODS: We performed metabolomics on irradiated and untreated H3K27M isogenic DMG cell lines and observed an H3K27M-specific enrichment for purine synthesis pathways. We profiled the expression of purine synthesis enzymes in publicly available patient data and our models, quantified purine synthesis using stable isotope tracing, and characterized the in vitro and in vivo response to de novo and salvage purine synthesis inhibition in combination with RT.
RESULTS: DMG-H3K27M cells activate purine metabolism in an H3K27M-specific fashion. In the absence of genotoxic treatment, H3K27M-expressing cells have higher relative activity of de novo synthesis and apparent lower activity of purine salvage demonstrated via stable isotope tracing of key metabolites in purine synthesis and by lower expression of hypoxanthine-guanine phosphoribosyltransferase (HGPRT), the rate-limiting enzyme of purine salvage into IMP and GMP. Inhibition of de novo guanylate synthesis radiosensitized DMG-H3K27M cells in vitro and in vivo. Irradiated H3K27M cells upregulated HGPRT expression and hypoxanthine-derived guanylate salvage but maintained high levels of guanine-derived salvage. Exogenous guanine supplementation decreased radiosensitization in cells treated with combination RT and de novo purine synthesis inhibition. Silencing HGPRT combined with RT markedly suppressed DMG-H3K27M tumor growth in vivo.
CONCLUSIONS: Our results indicate that DMG-H3K27M cells rely on highly active purine synthesis, both from the de novo and salvage synthesis pathways. However, highly active salvage of free purine bases into mature guanylates can bypass inhibition of the de novo synthetic pathway. We conclude that inhibiting purine salvage may be a promising strategy to overcome treatment resistance in DMG-H3K27M tumors.

Keywords:  Diffuse midline glioma; H3K27M; Purine metabolism; Radiation therapy resistance

DOI:  https://doi.org/10.1186/s40170-024-00341-7
Br J Cancer. 2024 Apr 06.

DRP1 inhibition-mediated mitochondrial elongation abolishes cancer stemness, enhances glutaminolysis, and drives ferroptosis in oral squamous cell carcinoma.

Zhen Wang, Shouyi Tang, Luyao Cai, Qing Wang, Dan Pan, Yunmei Dong, Hao Zhou, Jing Li, Ning Ji, Xin Zeng, Yu Zhou, Ying-Qiang Shen, Qianming Chen.

BACKGROUND: Mitochondrial dynamics play a fundamental role in determining stem cell fate. However, the underlying mechanisms of mitochondrial dynamics in the stemness acquisition of cancer cells are incompletely understood.
METHODS: Metabolomic profiling of cells were analyzed by MS/MS. The genomic distribution of H3K27me3 was measured by CUT&Tag. Oral squamous cell carcinoma (OSCC) cells depended on glucose or glutamine fueling TCA cycle were monitored by 13C-isotope tracing. Organoids and tumors from patients and mice were treated with DRP1 inhibitors mdivi-1, ferroptosis inducer erastin, or combination with mdivi-1 and erastin to evaluate treatment effects.
RESULTS: Mitochondria of OSCC stem cells own fragment mitochondrial network and DRP1 is required for maintenance of their globular morphology. Imbalanced mitochondrial dynamics induced by DRP1 knockdown suppressed stemness of OSCC cells. Elongated mitochondria increased α-ketoglutarate levels and enhanced glutaminolysis to fuel the TCA cycle by increasing glutamine transporter ASCT2 expression. α-KG promoted the demethylation of histone H3K27me3, resulting in downregulation of SNAI2 associated with stemness and EMT. Significantly, suppressing DRP1 enhanced the anticancer effects of ferroptosis.
CONCLUSION: Our study reveals a novel mechanism underlying mitochondrial dynamics mediated cancer stemness acquisition and highlights the therapeutic potential of mitochondria elongation to increase the susceptibility of cancer cells to ferroptosis.

DOI: https://doi.org/10.1038/s41416-024-02670-2
Mitochondrion. 2024 Apr 08. pii: S1567-7249(24)00040-0. [Epub ahead of print] 101882

Machine learning-based 3D segmentation of mitochondria in polarized epithelial cells.

Nan W Hultgren, Tianli Zhou, David S Williams.

  Mitochondria are dynamic organelles that alter their morphological characteristics in response to functional needs. Therefore, mitochondrial morphology is an important indicator of mitochondrial function and cellular health. Reliable segmentation of mitochondrial networks in microscopy images is a crucial initial step for further quantitative evaluation of their morphology. However, 3D mitochondrial segmentation, especially in cells with complex network morphology, such as in highly polarized cells, remains challenging. To improve the quality of 3D segmentation of mitochondria in super-resolution microscopy images, we took a machine learning approach, using 3D Trainable Weka, an ImageJ plugin. We demonstrated that, compared with other commonly used methods, our approach segmented mitochondrial networks effectively, with improved accuracy in different polarized epithelial cell models, including differentiated human retinal pigment epithelial (RPE) cells. Furthermore, using several tools for quantitative analysis following segmentation, we revealed mitochondrial fragmentation in bafilomycin-treated RPE cells.

Keywords:  3D segmentation; ImageJ; Machine learning algorithm; Mitochondrial morphology; Retinal pigment epithelium

DOI:  https://doi.org/10.1016/j.mito.2024.101882
bioRxiv. 2024 Mar 27. pii: 2024.03.24.584499. [Epub ahead of print]

An Innovative Mitochondrial-targeted Gene Therapy for Cancer Treatment.

Kai Chen, Patrick Ernst, Seulhee Kim, Yingnan Si, Tanvi Varadkar, Matthew D Ringel, Xiaoguang Margaret Liu, Lufang Zhou.

Targeting cancer cell mitochondria holds great therapeutic promise, yet current strategies to specifically and effectively destroy cancer mitochondria in vivo are limited. Here, we introduce mLumiOpto, an innovative mitochondrial-targeted luminoptogenetics gene therapy designed to directly disrupt the inner mitochondrial membrane (IMM) potential and induce cancer cell death. We synthesize a blue light-gated channelrhodopsin (CoChR) in the IMM and co-express a blue bioluminescence-emitting Nanoluciferase (NLuc) in the cytosol of the same cells. The mLumiOpto genes are selectively delivered to cancer cells in vivo by using adeno-associated virus (AAV) carrying a cancer-specific promoter or cancer-targeted monoclonal antibody-tagged exosome-associated AAV. Induction with NLuc luciferin elicits robust endogenous bioluminescence, which activates mitochondrial CoChR, triggering cancer cell IMM permeability disruption, mitochondrial damage, and subsequent cell death. Importantly, mLumiOpto demonstrates remarkable efficacy in reducing tumor burden and killing tumor cells in glioblastoma or triple-negative breast cancer xenografted mouse models. These findings establish mLumiOpto as a novel and promising therapeutic strategy by targeting cancer cell mitochondria in vivo .

DOI: https://doi.org/10.1101/2024.03.24.584499
Meat Sci. 2024 Apr 07. pii: S0309-1740(24)00087-1. [Epub ahead of print]213 109510

Inhibition of pyruvate dehydrogenase accelerates anaerobic glycolysis under postmortem simulating conditions.

Mackenzie J Taylor, Chandler D Stafford, Jared F Buhler, David S Dang, Mohammed A Alruzzi, Teif A Najm, Samuel D Gerrard, Kara J Thornton, Stephan van Vliet, Samer W El-Kadi, David E Gerrard, Sulaiman K Matarneh.

  This research aimed to explore the potential influence of mitochondria on the rate of anaerobic glycolysis. We hypothesized that mitochondria could reduce the rate of anaerobic glycolysis and pH decline by metabolizing a portion of glycolytic pyruvate. We utilized an in vitro model and incorporated CPI-613 and Avidin to inhibit pyruvate dehydrogenase (PDH) and pyruvate carboxylase (PC), respectively. Four treatments were tested: 400 μM CPI-613, 1.5 U/ml Avidin, 400 μM CPI-613 + 1.5 U/ml Avidin, or control. Glycolytic metabolites and pH of the in vitro model were evaluated throughout a 1440-min incubation period. CPI-613-containing treatments, with or without Avidin, decreased pH levels and increased glycogen degradation and lactate accumulation compared to the control and Avidin treatments (P < 0.05), indicating increased glycolytic flux. In a different experiment, two treatments, 400 μM CPI-613 or control, were employed to track the fates of pyruvate using [13C6]glucose. CPI-613 reduced the contribution of glucose carbon to tricarboxylic acid cycle intermediates compared to control (P < 0.05). To test whether the acceleration of acidification in reactions containing CPI-613 was due to an increase in the activity of key enzymes of glycogenolysis and glycolysis, we evaluated the activities of glycogen phosphorylase, phosphofructokinase, and pyruvate kinase in the presence or absence of 400 μM CPI-613. The CPI-613 treatment did not elicit an alteration in the activity of these three enzymes. These findings indicate that inhibiting PDH increases the rate of anaerobic glycolysis and pH decline, suggesting that mitochondria are potential regulators of postmortem metabolism.

Keywords:  Glycolysis; Isotope tracer; Mitochondria; Pyruvate dehydrogenase; TCA; pH

DOI:  https://doi.org/10.1016/j.meatsci.2024.109510
Nutrients. 2024 Mar 28. pii: 997. [Epub ahead of print]16(7):

Rescue of Methionine Dependence by Cobalamin in a Human Colorectal Cancer Cell Line.

Sarita Garg, Isabelle R Miousse.

  Methionine dependence is a characteristic of most cancer cells where they are unable to proliferate when the essential amino acid methionine is replaced with its precursor homocysteine in the growing media. Normal cells, on the other hand, thrive under these conditions and are referred to as methionine-independent. The reaction that adds a methyl group from 5-methyltetrahydrofolate to homocysteine to regenerate methionine is catalyzed by the enzyme methionine synthase with the cofactor cobalamin (vitamin B12). However, decades of research have shown that methionine dependence in cancer is not due to a defect in the activity of methionine synthase. Cobalamin metabolism has been tied to the dependent phenotype in rare cell lines. We have identified a human colorectal cancer cell line in which the cells regain the ability to proliferation in methionine-free, L-homocystine-supplemented media when cyanocobalamin is supplemented at a level of 1 µg/mL. In human SW48 cells, methionine replacement with L-homocystine does not induce any measurable increase in apoptosis or reactive oxygen species production in this cell line. Rather, proliferation is halted, then restored in the presence of cyanocobalamin. Our data show that supplementation with cyanocobalamin prevents the activation of the integrated stress response (ISR) in methionine-deprived media in this cell line. The ISR-associated cell cycle arrest, characteristic of methionine-dependence in cancer, is also prevented, leading to the continuation of proliferation in methionine-deprived SW48 cells with cobalamin. Our results highlight differences between cancer cell lines in the response to cobalamin supplementation in the context of methionine dependence.

Keywords:  cell cycle; cobalamin; colorectal cancer; methionine

DOI:  https://doi.org/10.3390/nu16070997
RNA. 2024 Apr 12. pii: rna.079925.123. [Epub ahead of print]

Cytosolic RNA binding of the mitochondrial TCA cycle enzyme malate dehydrogenase (MDH2).

Michelle Noble, Aindrila Chatterjee, Thileepan Sekaran, Thomas Schwarzl, Matthias W Hentze.

  Several enzymes of intermediary metabolism have been identified to bind RNA in 2 cells, with potential consequences for the bound RNAs and/or the enzyme. In this 3 study, we investigate the RNA-binding activity of the mitochondrial enzyme malate 4 dehydrogenase 2 (MDH2), which functions in the tricarboxylic acid (TCA) cycle and 5 the malate-aspartate shuttle. We confirmed in cellulo RNA-binding of MDH2 using 6 orthogonal biochemical assays and performed enhanced crosslinking and 7 immunoprecipitation (eCLIP) to identify the cellular RNAs associated with endogenous 8 MDH2. Surprisingly, MDH2 preferentially binds cytosolic over mitochondrial RNAs, 9 although the latter are abundant in the milieu of the mature protein. Subcellular 10 fractionation followed by RNA-binding assays revealed that MDH2-RNA interactions 11 occur predominantly outside of mitochondria. We also found that a cytosolically-12 retained N-terminal deletion mutant of MDH2 is competent to bind RNA, indicating that 13 mitochondrial targeting is dispensable for MDH2-RNA interactions. MDH2 RNA 14 binding increased when cellular NAD+ levels (MDH2's co-factor) was 15 pharmacologically diminished, suggesting that the metabolic state of cells affects RNA 16 binding. Taken together, our data implicate an as yet unidentified function of MDH2 17 binding RNA in the cytosol.

Keywords:  MDH2; RNA-binding proteins; metabolic enzymes

DOI:  https://doi.org/10.1261/rna.079925.123
Oxf Open Neurosci. 2023 ;2 kvad008

Glioblastoma modeling with 3D organoids: progress and challenges.

Xin Wang, Yusha Sun, Daniel Y Zhang, Guo-Li Ming, Hongjun Song.

  Glioblastoma (GBM) is the most aggressive adult primary brain tumor with nearly universal treatment resistance and recurrence. The mainstay of therapy remains maximal safe surgical resection followed by concurrent radiation therapy and temozolomide chemotherapy. Despite intensive investigation, alternative treatment options, such as immunotherapy or targeted molecular therapy, have yielded limited success to achieve long-term remission. This difficulty is partly due to the lack of pre-clinical models that fully recapitulate the intratumoral and intertumoral heterogeneity of GBM and the complex tumor microenvironment. Recently, GBM 3D organoids originating from resected patient tumors, genetic manipulation of induced pluripotent stem cell (iPSC)-derived brain organoids and bio-printing or fusion with non-malignant tissues have emerged as novel culture systems to portray the biology of GBM. Here, we highlight several methodologies for generating GBM organoids and discuss insights gained using such organoid models compared to classic modeling approaches using cell lines and xenografts. We also outline limitations of current GBM 3D organoids, most notably the difficulty retaining the tumor microenvironment, and discuss current efforts for improvements. Finally, we propose potential applications of organoid models for a deeper mechanistic understanding of GBM and therapeutic development.

Keywords:  3-dimensional; brain tumor; glioblastoma; modeling; organoids

DOI:  https://doi.org/10.1093/oons/kvad008
Biomicrofluidics. 2024 Mar;18(2): 024106

Epithelial and mesenchymal phenotypes determine the dynamics of circulating breast tumor cells in microfluidic capillaries under chemotherapy-induced stress.

Rong Du, Xiaoning Han, Linhong Deng, Xiang Wang.

Circulating tumor cells (CTCs) with different epithelial and mesenchymal phenotypes play distinct roles in the metastatic cascade. However, the influence of their phenotypic traits and chemotherapy on their transit and retention within capillaries remains unclear. To explore this, we developed a microfluidic device comprising 216 microchannels of different widths from 5 to 16 μm to mimic capillaries. This platform allowed us to study the behaviors of human breast cancer epithelial MCF-7 and mesenchymal MDA-MB-231 cells through microchannels under chemotherapy-induced stress. Our results revealed that when the cell diameter to microchannel width ratio exceeded 1.2, MCF-7 cells exhibited higher transit percentages than MDA-MB-231 cells under a flow rate of 0.13 mm/s. Tamoxifen (250 nM) reduced the transit percentage of MCF-7 cells, whereas 100 nM paclitaxel decreased transit percentages for both cell types. These differential responses were partially due to altered cell stiffness following drug treatments. When cells were entrapped at microchannel entrances, tamoxifen, paclitaxel, and high-flow stress (0.5 mm/s) induced a reduction in mitochondrial membrane potential (MMP) in MCF-7 cells. Tamoxifen treatment also elevated reactive oxygen species (ROS) levels in MCF-7 cells. Conversely, MMP and ROS levels in entrapped MDA-MB-231 cells remained unaffected. Consequently, the viability and proliferation of entrapped MCF-7 cells declined under these chemical and physical stress conditions. Our findings emphasize that phenotypically distinct CTCs may undergo selective filtration and exhibit varied responses to chemotherapy in capillaries, thereby impacting cancer metastasis outcomes. This highlights the importance of considering both cell phenotype and drug response to improve treatment strategies.

DOI: https://doi.org/10.1063/5.0188861
J Clin Med. 2024 Apr 01. pii: 2046. [Epub ahead of print]13(7):

Venetoclax Combination Treatment of Acute Myeloid Leukemia in Adolescents and Young Adult Patients.

Elena Chatzikalil, Kleoniki Roka, Panagiotis T Diamantopoulos, Efthymia Rigatou, Georgia Avgerinou, Antonis Kattamis, Elena E Solomou.

  Over the past two decades, the prognosis in adolescents and young adults (AYAs) diagnosed with acute myeloid leukemia (AML) has significantly improved. The standard intensive cytotoxic treatment approach for AYAs with AML, consisting of induction chemotherapy with anthracycline/cytarabine combination followed by consolidation chemotherapy or stem cell transplantation, has lately been shifting toward novel targeted therapies, mostly in the fields of clinical trials. One of the most recent advances in treating AML is the combination of the B-cell lymphoma 2 (Bcl-2) inhibitor venetoclax with hypomethylating agents, which has been studied in elderly populations and was approved by the Food and Drug Administration (FDA) for patients over 75 years of age or patients excluded from intensive chemotherapy induction schemas due to comorbidities. Regarding the AYA population, venetoclax combination therapy could be a therapeutic option for patients with refractory/relapsed (R/R) AML, although data from real-world studies are currently limited. Venetoclax is frequently used by AYAs diagnosed with advanced hematologic malignancies, mainly acute lymphoblastic leukemia and myelodysplastic syndromes, as a salvage therapeutic option with considerable efficacy and safety. Herein, we aim to summarize the evidence obtained from clinical trials and observational studies on venetoclax use in AYAs with AML. Based on the available evidence, venetoclax is a safe and effective therapeutic option for R/R AML AYA patients. However, further research in larger cohorts is needed to confirm these data, establishing the benefits of a venetoclax-based regimen for this special population.

Keywords:  Bcl-2 inhibitor; acute myeloid leukemia; adolescents; targeted therapy; venetoclax; young adults

DOI:  https://doi.org/10.3390/jcm13072046
Cell Rep. 2024 Apr 10. pii: S2211-1247(24)00375-9. [Epub ahead of print]43(4): 114047

LDHB contributes to the regulation of lactate levels and basal insulin secretion in human pancreatic β cells.

Federica Cuozzo, Katrina Viloria, Ali H Shilleh, Daniela Nasteska, Charlotte Frazer-Morris, Jason Tong, Zicong Jiao, Adam Boufersaoui, Bryan Marzullo, Daniel B Rosoff, Hannah R Smith, Caroline Bonner, Julie Kerr-Conte, Francois Pattou, Rita Nano, Lorenzo Piemonti, Paul R V Johnson, Rebecca Spiers, Jennie Roberts, Gareth G Lavery, Anne Clark, Carlo D L Ceresa, David W Ray, Leanne Hodson, Amy P Davies, Guy A Rutter, Masaya Oshima, Raphaël Scharfmann, Matthew J Merrins, Ildem Akerman, Daniel A Tennant, Christian Ludwig, David J Hodson.

  Using 13C6 glucose labeling coupled to gas chromatography-mass spectrometry and 2D 1H-13C heteronuclear single quantum coherence NMR spectroscopy, we have obtained a comparative high-resolution map of glucose fate underpinning β cell function. In both mouse and human islets, the contribution of glucose to the tricarboxylic acid (TCA) cycle is similar. Pyruvate fueling of the TCA cycle is primarily mediated by the activity of pyruvate dehydrogenase, with lower flux through pyruvate carboxylase. While the conversion of pyruvate to lactate by lactate dehydrogenase (LDH) can be detected in islets of both species, lactate accumulation is 6-fold higher in human islets. Human islets express LDH, with low-moderate LDHA expression and β cell-specific LDHB expression. LDHB inhibition amplifies LDHA-dependent lactate generation in mouse and human β cells and increases basal insulin release. Lastly, cis-instrument Mendelian randomization shows that low LDHB expression levels correlate with elevated fasting insulin in humans. Thus, LDHB limits lactate generation in β cells to maintain appropriate insulin release.

Keywords:  CP: Metabolism; GC-MS; LDH; NMR; glucose tracing; imaging; islet; lactate; metabolism; pyruvate; pyruvate dehydrogenase

DOI:  https://doi.org/10.1016/j.celrep.2024.114047
Obesity (Silver Spring). 2024 Apr 10.

Impact of sustained calorie restriction and weight cycling on body composition in high-fat diet-fed male and female C57BL/6J mice.

Daniel L Smith, Yongbin Yang, Luis M Mestre, Beate Henschel, Erik Parker, Stephanie Dickinson, Amit Patki, David B Allison, Tim R Nagy.

OBJECTIVE: The objective of this study was to investigate body composition changes with weight cycling (WC) among adult C57BL/6J mice with diet-induced obesity.
METHODS: A total of 555 single-housed mice were fed a high-fat diet ad libitum (AL) from 8 to 43 weeks of age. The 200 heaviest mice of each sex were randomized to the following four groups: ever obese (EO, continued AL feeding); obese weight loser (OWL, calorie-restricted); obese weight loser moderate (OWLM, body weight halfway between EO and OWL); and WC (diet restricted to OWL followed by AL refeeding cycles). Body weight and composition data were collected. Linear regression was used to calculate residuals between predicted and observed fat mass. Linear mixed models were used to compare diet groups.
RESULTS: Although weight loss and regain resulted in changes in body weight and composition, fat mass, body weight, and relative body fat were not significantly greater for the WC group compared with the EO group. During long-term calorie restriction, males (but not females) in the OWLM group remained relatively fatter than the EO group.
CONCLUSIONS: WC did not increase body weight or relative fat mass for middle-aged, high-fat diet-fed adult mice. However, long-term moderate calorie restriction resulted in lower body weight but greater "relative" fat in male mice.

DOI: https://doi.org/10.1002/oby.24015
Bioorg Med Chem. 2024 Apr 03. pii: S0968-0896(24)00126-3. [Epub ahead of print]104 117712

Human mitochondrial glutathione transferases: Kinetic parameters and accommodation of a mitochondria-targeting group in substrates.

Patrick A Cardwell, Carlo Del Moro, Michael P Murphy, Adrian J Lapthorn, Richard C Hartley.

  Glutathione-S-transferases are key to the cellular detoxification of xenobiotics and products of oxidative damage. GSTs catalyse the reaction of glutathione (GSH) with electrophiles to form stable thioether adducts. GSTK1-1 is the main GST isoform in the mitochondrial matrix, but the GSTA1-1 and GSTA4-4 isoforms are also thought to be in the mitochondria with their distribution altering in transformed cells, thus potentially providing a cancer specific target. A mitochondria-targeted version of the GST substrate 1-chloro-2,4-dinitrobenzene (CDNB), MitoCDNB, has been used to manipulate the mitochondrial GSH pool. To finesse this approach to target particular GST isoforms in the context of cancer, here we have determined the kcat/Km for the human isoforms of GSTK1-1, GSTA1-1 and GSTA4-4 with respect to GSH and CDNB. We show how the rate of the GST-catalysed reaction between GSH and CDNB analogues can be modified by both the electron withdrawing substituents, and by the position of the mitochondria-targeting triphenylphosphonium on the chlorobenzene ring to tune the activity of mitochondria-targeted substrates. These findings can now be exploited to selectively disrupt the mitochondrial GSH pools of cancer cells expressing particular GST isoforms.

Keywords:  Cancer; Glutathione; Glutathione-S-transferase; Mitochondria; Oxidative stress

DOI:  https://doi.org/10.1016/j.bmc.2024.117712
Cancers (Basel). 2024 Mar 28. pii: 1325. [Epub ahead of print]16(7):

Role of SGLT2 Inhibitors, DPP-4 Inhibitors, and Metformin in Pancreatic Cancer Prevention.

Tooba Laeeq, Maheen Ahmed, Hina Sattar, Muhammad Hamayl Zeeshan, Meher Binte Ali.

  Pancreatic carcinoma is a highly aggressive tumor that usually presents when it has already metastasized. Therapeutic options for cure remain scarce and rely on combination chemotherapy with limited sustainability. Diabetes is considered an important risk factor for the development of pancreatic cancer due to the production of proinflammatory cytokines, which result in increased cell proliferation. More than half of patients diagnosed with pancreatic cancer eventually develop diabetes due to the destruction of insulin-producing cells. The interlinkage of both diseases might identify a possible preventative strategy for reducing the incidence of pancreatic carcinoma. This study reviewed the recent literature on the association between pancreatic cancer risk and SGLT2 inhibitors, GLP-1 RA, DPP-4 inhibitors, and biguanides. There are mixed data regarding the relationship between GLP-1 RA and DPP-4 inhibitors and pancreatic cancer, with some trials suggesting that they might increase the risk. In contrast, studies have mostly revealed that SGLT2 inhibitors have an antiproliferative effect on various tumors, such as liver, pancreatic, prostate, bowel, lung, and breast carcinoma, which might be due to their mechanism of blockage of reabsorption of glucose by cells, lowering the amount of available glucose for the growth of tumor cells. Metformin, the first-line agent for diabetes, has also been shown to be associated with decreasing pancreatic cancer risk and improving prognosis in those who already have the disease. Dedicated trials are needed to further delineate the association of antidiabetic drugs with the risk of pancreatic cancer in the general population, as previous studies have mostly focused on diabetic patients.

Keywords:  anti-diabetic drugs; diabetes; pancreatic cancer; prevention; risk

DOI:  https://doi.org/10.3390/cancers16071325
Mol Metab. 2024 Apr 09. pii: S2212-8778(24)00065-6. [Epub ahead of print] 101934

Hepatic ketone body regulation of renal gluconeogenesis.

Ryo Hatano, Eunyoung Lee, Hiromi Sato, Masahiro Kiuchi, Kiyoshi Hirahara, Yoshimi Nakagawa, Hitoshi Shimano, Toshinori Nakayama, Tomoaki Tanaka, Takashi Miki.

   OBJECTIVES: During fasting, liver pivotally regulates blood glucose levels through glycogenolysis and gluconeogenesis. Kidney also produces glucose through gluconeogenesis. Gluconeogenic genes are transactivated by fasting, but their expression patterns are chronologically different between the two organs. We find that renal gluconeogenic gene expressions are positively correlated with the blood β-hydroxybutyrate concentration. Thus, we herein aim to investigate the regulatory mechanism and its physiological implications.
METHODS: Gluconeogenic gene expressions in liver and kidney were examined in hyperketogenic mice such as high fat diet (HFD)-fed and ketogenic diet-fed mice, and in hypoketogenic PPARα knockout (PPARα-/-) mice. Renal gluconeogenesis was evaluated by rise in glycemia after glutamine loading in vivo. Functional roles of β-hydroxybutyrate in the regulation of renal gluconeogenesis were investigated by metabolome analysis and RNA-seq analysis of proximal tubule cells.
RESULTS: Renal gluconeogenic genes were transactivated concurrently with blood β-hydroxybutyrate uprise under ketogenic states, but the increase was blunted in hypoketogenic PPARα-/- mice. Administration of 1,3-butandiol, a ketone diester, transactivated renal gluconeogenic gene expression in fasted PPARα-/- mice. In addition, HFD-fed mice showed fasting hyperglycemia along with upregulated renal gluconeogenic gene expression, which was blunted in HFD-fed PPARα-/- mice. In vitro experiments and metabolome analysis in renal tubular cells showed that β-hydroxybutyrate directly promotes glucose and NH3 production through transactivating gluconeogenic genes. In addition, RNA-seq analysis revealed that β-hydroxybutyrate-induced transactivation of Pck1 was mediated by C/EBPβ.
CONCLUSIONS: Our findings demonstrate that β-hydroxybutyrate mediates hepato-renal interaction to maintain homeostatic regulation of blood glucose and systemic acid-base balance through renal gluconeogenesis regulation.

Keywords:  acid-base homeostasis; glucose metabolism; ketone bodies; renal gluconeogenesis

DOI:  https://doi.org/10.1016/j.molmet.2024.101934
Acta Neuropathol. 2024 Apr 07. 147(1): 68

Metabologenomic characterization uncovers a clinically aggressive IDH mutant glioma subtype.

Farshad Nassiri, Andrew Ajisebutu, Vikas Patil, Yasin Mamatjan, Jeff Liu, Justin Z Wang, Mathew R Voisin, Romina Nejad, Sheila Mansouri, Shirin Karimi, Ankur Chakravarthy, Eric Chen, Daniel D De Carvalho, Kenneth Aldape, Gelareh Zadeh.

Mutations in the pivotal metabolic isocitrate dehydrogenase (IDH) enzymes are recognized to drive the molecular footprint of diffuse gliomas, and patients with IDH mutant gliomas have overall favorable outcomes compared to patients with IDH wild-type tumors. However, survival still varies widely among patients with IDH mutated tumors. Here, we aimed to characterize molecular signatures that explain the range of IDH mutant gliomas. By integrating matched epigenome-wide methylome, transcriptome, and global metabolome data in 154 patients with gliomas, we identified a group of IDH mutant gliomas with globally altered metabolism that resembled IDH wild-type tumors. IDH-mutant gliomas with altered metabolism have significantly shorter overall survival from their IDH mutant counterparts that is not fully accounted for by recognized molecular prognostic markers of CDKN2A/B loss and glioma CpG Island Methylator Phenotype (GCIMP) status. IDH-mutant tumors with dysregulated metabolism harbored distinct epigenetic alterations that converged to drive proliferative and stem-like transcriptional profiles, providing a window to target novel dependencies in gliomas.

DOI: https://doi.org/10.1007/s00401-024-02713-1
Fluids Barriers CNS. 2024 Apr 08. 21(1): 33

Fasting upregulates the monocarboxylate transporter MCT1 at the rat blood-brain barrier through PPAR δ activation.

Stéphanie Chasseigneaux, Véronique Cochois-Guégan, Lucas Lecorgne, Murielle Lochus, Sophie Nicolic, Corinne Blugeon, Laurent Jourdren, David Gomez-Zepeda, Stefan Tenzer, Sylvia Sanquer, Valérie Nivet-Antoine, Marie-Claude Menet, Jean-Louis Laplanche, Xavier Declèves, Salvatore Cisternino, Bruno Saubaméa.

   BACKGROUND: The blood-brain barrier (BBB) is pivotal for the maintenance of brain homeostasis and it strictly regulates the cerebral transport of a wide range of endogenous compounds and drugs. While fasting is increasingly recognized as a potential therapeutic intervention in neurology and psychiatry, its impact upon the BBB has not been studied. This study was designed to assess the global impact of fasting upon the repertoire of BBB transporters.
METHODS: We used a combination of in vivo and in vitro experiments to assess the response of the brain endothelium in male rats that were fed ad libitum or fasted for one to three days. Brain endothelial cells were acutely purified and transcriptionaly profiled using RNA-Seq. Isolated brain microvessels were used to assess the protein expression of selected BBB transporters through western blot. The molecular mechanisms involved in the adaptation to fasting were investigated in primary cultured rat brain endothelial cells. MCT1 activity was probed by in situ brain perfusion.
RESULTS: Fasting did not change the expression of the main drug efflux ATP-binding cassette transporters or P-glycoprotein activity at the BBB but modulated a restrictive set of solute carrier transporters. These included the ketone bodies transporter MCT1, which is pivotal for the brain adaptation to fasting. Our findings in vivo suggested that PPAR δ, a major lipid sensor, was selectively activated in brain endothelial cells in response to fasting. This was confirmed in vitro where pharmacological agonists and free fatty acids selectively activated PPAR δ, resulting in the upregulation of MCT1 expression. Moreover, dosing rats with a specific PPAR δ antagonist blocked the upregulation of MCT1 expression and activity induced by fasting.
CONCLUSIONS: Altogether, our study shows that fasting affects a selected set of BBB transporters which does not include the main drug efflux transporters. Moreover, we describe a previously unknown selective adaptive response of the brain vasculature to fasting which involves PPAR δ and is responsible for the up-regulation of MCT1 expression and activity. Our study opens new perspectives for the metabolic manipulation of the BBB in the healthy or diseased brain.

Keywords:  Blood-brain barrier; Endothelial cells; Fasting; MCT1; PPAR δ

DOI:  https://doi.org/10.1186/s12987-024-00526-8
Front Oncol. 2024 ;14 1343061

Altered lipid metabolism in APC-driven colorectal cancer: the potential for therapeutic intervention.

Courtney O Kelson, Yekaterina Y Zaytseva.

  Altered lipid metabolism is a well-recognized feature of solid cancers, including colorectal cancer. In colorectal cancer, upregulation of lipid metabolism contributes to initiation, progression, and metastasis; thus, aberrant lipid metabolism contributes to a poor patient outcome. The inactivating mutation of APC, a vital tumor suppressor in the Wnt signaling pathway, is a key event that occurs early in the majority of colorectal cancer cases. The potential crosstalk between lipid metabolism and APC-driven colorectal cancer is poorly understood. This review collectively highlights and summarizes the limited understanding between mutations in APC and the upregulation of Wnt/beta-catenin signaling and lipid metabolism. The interconnection between APC inactivation and aberrant lipid metabolism activates Wnt/beta-catenin signaling which causes transcriptome, epigenetic, and microbiome changes to promote colorectal cancer initiation and progression. Furthermore, the downstream effects of this collaborative effort between aberrant Wnt/beta-catenin signaling and lipid metabolism are enhanced stemness, cellular proliferation, prooncogenic signaling, and survival. Understanding the mechanistic link between APC inactivation and alterations in lipid metabolism may foster identification of new therapeutic targets to enable development of more efficacious strategies for prevention and/or treatment of colorectal cancer.

Keywords:  APC gene; APC-mediated signaling; colorectal cancer; lipid metabolism; lipids

DOI:  https://doi.org/10.3389/fonc.2024.1343061
Nat Cell Biol. 2024 Apr 08.

A lipid atlas of human and mouse immune cells provides insights into ferroptosis susceptibility.

Pooranee K Morgan, Gerard Pernes, Kevin Huynh, Corey Giles, Sudip Paul, Adam Alexander T Smith, Natalie A Mellett, Amy Liang, Tilly van Buuren-Milne, Camilla Bertuzzo Veiga, Thomas J C Collins, Yangsong Xu, Man K S Lee, T Michael De Silva, Peter J Meikle, Graeme I Lancaster, Andrew J Murphy.

The cellular lipidome comprises thousands of unique lipid species. Here, using mass spectrometry-based targeted lipidomics, we characterize the lipid landscape of human and mouse immune cells ( www.cellularlipidatlas.com ). Using this resource, we show that immune cells have unique lipidomic signatures and that processes such as activation, maturation and development impact immune cell lipid composition. To demonstrate the potential of this resource to provide insights into immune cell biology, we determine how a cell-specific lipid trait-differences in the abundance of polyunsaturated fatty acid-containing glycerophospholipids (PUFA-PLs)-influences immune cell biology. First, we show that differences in PUFA-PL content underpin the differential susceptibility of immune cells to ferroptosis. Second, we show that low PUFA-PL content promotes resistance to ferroptosis in activated neutrophils. In summary, we show that the lipid landscape is a defining feature of immune cell identity and that cell-specific lipid phenotypes underpin aspects of immune cell physiology.

DOI: https://doi.org/10.1038/s41556-024-01377-z
Proc Natl Acad Sci U S A. 2024 Apr 16. 121(16): e2318444121

Modeling of brain efflux: Constraints of brain surfaces.

Peter A R Bork, Natalie L Hauglund, Yuki Mori, Kjeld Møllgård, Poul G Hjorth, Maiken Nedergaard.

  Fluid efflux from the brain plays an important role in solute waste clearance. Current experimental approaches provide little spatial information, and data collection is limited due to short duration or low frequency of sampling. One approach shows tracer efflux to be independent of molecular size, indicating bulk flow, yet also decelerating like simple membrane diffusion. In an apparent contradiction to this report, other studies point to tracer efflux acceleration. We here develop a one-dimensional advection-diffusion model to gain insight into brain efflux principles. The model is characterized by nine physiological constants and three efflux parameters for which we quantify prior uncertainty. Using Bayes' rule and the two efflux studies, we validate the model and calculate data-informed parameter distributions. The apparent contradictions in the efflux studies are resolved by brain surface boundaries being bottlenecks for efflux. To critically test the model, a custom MRI efflux assay measuring solute dispersion in tissue and release to cerebrospinal fluid was employed. The model passed the test with tissue bulk flow velocities in the range 60 to 190 [Formula: see text]m/h. Dimensional analysis identified three principal determinants of efflux, highlighting brain surfaces as a restricting factor for metabolite solute clearance.

Keywords:  MRI; advection–diffusion; glymphatics

DOI:  https://doi.org/10.1073/pnas.2318444121
J Physiol Biochem. 2024 Apr 08.

Fasting and fasting-mimicking conditions in the cancer immunotherapy era.

Ruben Pio, Yaiza Senent, Beatriz Tavira, Daniel Ajona.

  Fasting and fasting-mimicking conditions modulate tumor metabolism and remodel the tumor microenvironment (TME), which could be exploited for the treatment of tumors. A body of evidence demonstrates that fasting and fasting-mimicking conditions can kill cancer cells, or sensitize them to the antitumor activity of standard-of-care drugs while protecting normal cells against their toxic side effects. Pre- and clinical data also suggest that immune responses are involved in these therapeutic effects. Therefore, there is increasing interest in evaluating the impact of fasting-like conditions in the efficacy of antitumor therapies based on the restoration or activation of antitumor immune responses. Here, we review the recent progress in the intersection of fasting-like conditions and current cancer treatments, with an emphasis on cancer immunotherapy.

Keywords:  Cancer immunotherapy; Cancer treatment toxic side effects; Fasting; Fasting-mimicking conditions; Tumor immunity

DOI:  https://doi.org/10.1007/s13105-024-01020-3
Islets. 2024 Dec 31. 16(1): 2339558

β cell acetate production and release are negligible.

Kai Xu, Chioma Nnyamah, Nupur Pandya, Nadia Sweis, Irene Corona-Avila, Medha Priyadarshini, Barton Wicksteed, Brian T Layden.

   BACKGROUND: Studies suggest that short chain fatty acids (SCFAs), which are primarily produced from fermentation of fiber, regulate insulin secretion through free fatty acid receptors 2 and 3 (FFA2 and FFA3). As these are G-protein coupled receptors (GPCRs), they have potential therapeutic value as targets for treating type 2 diabetes (T2D). The exact mechanism by which these receptors regulate insulin secretion and other aspects of pancreatic β cell function is unclear. It has been reported that glucose-dependent release of acetate from pancreatic β cells negatively regulates glucose stimulated insulin secretion. While these data raise the possibility of acetate's potential autocrine action on these receptors, these findings have not been independently confirmed, and multiple concerns exist with this observation, particularly the lack of specificity and precision of the acetate detection methodology used.
METHODS: Using Min6 cells and mouse islets, we assessed acetate and pyruvate production and secretion in response to different glucose concentrations, via liquid chromatography mass spectrometry.
RESULTS: Using Min6 cells and mouse islets, we showed that both intracellular pyruvate and acetate increased with high glucose conditions; however, intracellular acetate level increased only slightly and exclusively in Min6 cells but not in the islets. Further, extracellular acetate levels were not affected by the concentration of glucose in the incubation medium of either Min6 cells or islets.
CONCLUSIONS: Our findings do not substantiate the glucose-dependent release of acetate from pancreatic β cells, and therefore, invalidate the possibility of an autocrine inhibitory effect on glucose stimulated insulin secretion.

Keywords:  Acetate; FFA2 and FFA3; Insulin secretion; liquid chromatography mass spectrometry; pancreatic β cells

DOI:  https://doi.org/10.1080/19382014.2024.2339558
Curr Dev Nutr. 2024 Apr;8(4): 102134

Examining the Role of Nutrition in Cancer Survivorship and Female Fertility: A Narrative Review.

Cynthia Klobodu, Mara Z Vitolins, Jonathan M Deutsch, Kathleen Fisher, Jennifer A Nasser, Dahlia Stott, Michael J Murray, Laura Curtis, Brandy-Joe Milliron.

  Female cancer survivors have a higher chance of experiencing infertility than females without a history of cancer diagnosis. This risk remains high despite advances in fertility treatments. There is a need to augment fertility treatments with cost-effective methods such as nutritional guidance to improve fertility chances. The aim of this review article is to connect the current literature on cancer survivorship nutrition and fertility nutrition, focusing on the importance of integrating nutritional guidance into fertility counseling, assessment, and treatment for female cancer survivors. Consuming a healthful diet comprising whole grains, soy, fruits, vegetables, seafood, and unsaturated fats has improved both female fertility and cancer survivorship. Similarly, maintaining a healthy body weight also improves female fertility and cancer survivorship. Therefore, dietary interventions to support female cancer survivors with fertility challenges are of immense importance. The period of follow-up fertility counseling and assessment after cancer treatment may provide a unique opportunity for implementing nutritional guidance for female cancer survivors. Dietary interventions are a promising strategy to improve pregnancy chances and overall quality of life among female cancer survivors; thus, researchers should investigate perceptions regarding fertility, barriers, and challenges to changing nutrition-related behaviors, and preferences for nutritional guidance to support fertility treatments in this population.

Keywords:  diet; female cancer survivors; fertility counseling; infertility

DOI:  https://doi.org/10.1016/j.cdnut.2024.102134
Nutrients. 2024 Apr 08. pii: 1093. [Epub ahead of print]16(7):

Nutritional Quality Implications: Exploring the Impact of a Fatty Acid-Rich Diet on Central Nervous System Development.

Katarzyna Smolińska, Aleksandra Szopa, Jan Sobczyński, Anna Serefko, Piotr Dobrowolski.

  Given the comprehensive examination of the role of fatty acid-rich diets in central nervous system development in children, this study bridges significant gaps in the understanding of dietary effects on neurodevelopment. It delves into the essential functions of fatty acids in neurodevelopment, including their contributions to neuronal membrane formation, neuroinflammatory modulation, neurogenesis, and synaptic plasticity. Despite the acknowledged importance of these nutrients, this review reveals a lack of comprehensive synthesis in current research, particularly regarding the broader spectrum of fatty acids and their optimal levels throughout childhood. By consolidating the existing knowledge and highlighting critical research gaps, such as the effects of fatty acid metabolism on neurodevelopmental disorders and the need for age-specific dietary guidelines, this study sets a foundation for future studies. This underscores the potential of nutritional strategies to significantly influence neurodevelopmental trajectories, advocating an enriched academic and clinical understanding that can inform dietary recommendations and interventions aimed at optimizing neurological health from infancy.

Keywords:  central nervous system development; fatty acids and neurodevelopment; neurodevelopmental disorders; omega-3 fatty acids; pediatric nutrition

DOI:  https://doi.org/10.3390/nu16071093
Cell Rep Med. 2024 Apr 04. pii: S2666-3791(24)00168-X. [Epub ahead of print] 101500

Derivative survival analyses: Analysis methods to derive survival outcomes for the remainder patient cohort without individual patient data.

Niraj K Shenoy.

  It is not uncommon for industry-sponsored randomized controlled trials to publish survival curves/data for the overall patient cohort("A+B") and for a favorable subgroup ("A") pre-specified or post hoc, but not the survival curves/data for the remainder cohort("B"). Consequently, following regulatory approval of the intervention treatment for the overall patient population if the primary endpoint is met, it is common for cancer patients representing the remainder cohort (B) to be treated as per the results of the overall cohort (A+B). To overcome this important issue in clinical decision-making, this study aimed to identify methods to accurately derive the survival curves and/or hazard ratio (95% confidence interval) for the remainder cohort (B), utilizing published curves and hazard ratios (95% confidence intervals) of the overall (A+B) and favorable subgroup (A) cohorts. The analysis methods (method I and method II) presented here, termed "derivative survival analyses," enable accurate assessment of survival outcomes in the remainder cohort without individual patient data.

Keywords:  derivative analysis; immunotherapy; individual patient data; randomized controlled trials; remainder cohort; survival analysis

DOI:  https://doi.org/10.1016/j.xcrm.2024.101500