bims-medica 2023-11-05 papers

bims-medica

Biomed News

on Metabolism and diet in cancer

Issue of 2023–11–05
23 papers selected by
Brett Chrest, East Carolina University

Dietary approaches for controlling cancer by limiting the Warburg effect: a review.
Metabolic pathway analysis using stable isotopes in patients with cancer.
3,5-diCQA suppresses colorectal cancer cell growth through ROS/AMPK/mTOR mediated mitochondrial dysfunction and ferroptosis.
Combined inhibition of pyruvate dehydrogenase kinase 1 and hexokinase 2 induces apoptsis in non-small cell lung cancer cell models.
The iron chelator and OXPHOS inhibitor VLX600 induces mitophagy and an autophagy-dependent type of cell death in glioblastoma cells.
Medium Depth Influences O2 Availability and Metabolism in Human RPE Cultures.
HIF-1 inactivation empowers HIF-2 to drive hypoxia adaptation in aggressive forms of medulloblastoma.
Molecular Mechanism of Fasting-Mimicking Diet in Inhibiting Colorectal Cancer Progression: Implications for Immune Therapy and Metabolic Regulation.
Reactive oxygen species in colorectal cancer adjuvant therapies.
Metabolomic rewiring promotes endocrine therapy resistance in breast cancer.
Small-molecule redox modulators with anticancer activity: A comprehensive mechanistic update.
Imetelstat-mediated alterations in fatty acid metabolism to induce ferroptosis as a therapeutic strategy for acute myeloid leukemia.
Probing Human Heart TCA Cycle Metabolism and Response to Glucose Load using Hyperpolarized [2- 13 C]Pyruvate MR Spectroscopy.
Characteristics of amino acid metabolism in colorectal cancer.
SLC38A5 promotes glutamine metabolism and inhibits cisplatin chemosensitivity in breast cancer.
Real-time resolution studies of the regulation of pyruvate-dependent lactate metabolism by hexokinases in single cells.
A practical perspective on how to develop, implement, execute, and reproduce high-resolution respirometry experiments: The physiologist's guide to an Oroboros O2k.
Autoregulatory control of mitochondrial glutathione homeostasis.
Cancer-associated fibroblasts actively compress cancer cells and modulate mechanotransduction.
Non-immunotherapy approaches for Relapsed or Refractory AML: an update for 2024.
Natural compounds as lactate dehydrogenase inhibitors: potential therapeutics for lactate dehydrogenase inhibitors-related diseases.
The 'non-essential' amino acid cysteine is required to prevent ferroptosis in acute myeloid leukemia.
Clinically relevant humanized mouse models of metastatic prostate cancer to evaluate cancer therapies.

Nutr Rev. 2023 Oct 31. pii: nuad130. [Epub ahead of print]

Dietary approaches for controlling cancer by limiting the Warburg effect: a review.

Ghazaleh Shimi.

  Cancer is a mysterious disease. Among other alterations, tumor cells, importantly, have metabolic modifications. A well-known metabolic modification commonly observed in cancer cells has been termed the Warburg effect. This phenomenon is defined as a high preference for glucose uptake, and increased lactate production from that glucose, even when oxygen is readily available. Some anti-cancer drugs target the proposed Warburg effect, and some dietary regimens can function similarly. However, the most suitable dietary strategies for treating particular cancers are not yet well understood. The aim of this review was to describe findings regarding the impact of various proposed dietary regimens targeting the Warburg effect. The evidence suggests that combining routine cancer therapies with diet-based strategies may improve the outcome in treating cancer. However, designing individualized therapies must be our ultimate goal.

Keywords:  OXPHOS; cancer; diet; glycolysis; oxidative phosphorylation; the Warburg effect

DOI:  https://doi.org/10.1093/nutrit/nuad130
Nat Rev Cancer. 2023 Oct 31.

Metabolic pathway analysis using stable isotopes in patients with cancer.

Caroline R Bartman, Brandon Faubert, Joshua D Rabinowitz, Ralph J DeBerardinis.

Metabolic reprogramming is central to malignant transformation and cancer cell growth. How tumours use nutrients and the relative rates of reprogrammed pathways are areas of intense investigation. Tumour metabolism is determined by a complex and incompletely defined combination of factors intrinsic and extrinsic to cancer cells. This complexity increases the value of assessing cancer metabolism in disease-relevant microenvironments, including in patients with cancer. Stable-isotope tracing is an informative, versatile method for probing tumour metabolism in vivo. It has been used extensively in preclinical models of cancer and, with increasing frequency, in patients with cancer. In this Review, we describe approaches for using in vivo isotope tracing to define fuel preferences and pathway engagement in tumours, along with some of the principles that have emerged from this work. Stable-isotope infusions reported so far have revealed that in humans, tumours use a diverse set of nutrients to supply central metabolic pathways, including the tricarboxylic acid cycle and amino acid synthesis. Emerging data suggest that some activities detected by stable-isotope tracing correlate with poor clinical outcomes and may drive cancer progression. We also discuss current challenges in isotope tracing, including comparisons of in vivo and in vitro models, and opportunities for future discovery in tumour metabolism.

DOI: https://doi.org/10.1038/s41568-023-00632-z
Cell Cycle. 2023 Oct 30. 1-18

3,5-diCQA suppresses colorectal cancer cell growth through ROS/AMPK/mTOR mediated mitochondrial dysfunction and ferroptosis.

Weibing Wang, Xingwei Xu, Long Zhao, Kailun Ye, Saisai Wang, Caizhao Lin.

  3,5-diCQA has been shown to have anti-tumor effect by decreasing cancer cell growth. However, the molecular mechanism by which 3,5-diCQA impacts colorectal cancer (CRC) cells is unknown. This study discovered that 3,5-diCQA had a suppressive effect on CRC cells, mainly in the inhibition of proliferation, migration, and the enhancement of apoptosis in HCT116 and SW480 cells. Additionally, 3,5-diCQA was found to cause cell cycle arrest in CRC cells. Meanwhile, we found that 3,5-diCQA activates the AMPK pathway through the generation of ROS, mediates mitochondrial damage, and reduces mitochondrial aerobic glycolysis and oxidative phosphorylation levels. 3,5-diCQA promoted oxidative damage and ferroptosis in CRC cells. Hence, we added ROS inhibitor NAC and found that the NAC reversed the effects of 3,5-diCQA on proliferation, apoptosis, ROS generation, and ferroptosis in CRC cells. Moreover, 3,5-diCQA was also shown to suppress the development of CRC tumor in a tumor-forming model of nude mice. In conclusion, we found that 3,5-diCQA enhances the oxidative damage and ferroptosis while reducing proliferation and migration of CRC cells, depending on mitochondrial dysfunction caused by the ROS/AMPK/mTOR pathway.

Keywords:  3,5-diCQA; ROS/AMPK/mTOR pathway; colorectal cancer; ferroptosis; mitochondrial damage

DOI:  https://doi.org/10.1080/15384101.2023.2247248
Exp Cell Res. 2023 Oct 30. pii: S0014-4827(23)00381-6. [Epub ahead of print] 113830

Combined inhibition of pyruvate dehydrogenase kinase 1 and hexokinase 2 induces apoptsis in non-small cell lung cancer cell models.

Yizhen Guo, Xianchen Lua, Yan Zhou, Wen-Hua Chen, Kin Yip Tam.

  Many cancer cells exhibit enhanced glycolysis, which is seen as one of the hallmark metabolic alterations, known as Warburg effect. Substantial evidence shows that upregulated glycolytic enzymes are often linked to malignant growth. Using glycolytic inhibitors for anticancer treatment has become appealing in recent years for therapeutic intervention in cancers with highly glycolytic characteristic, including non-small cell lung cancer (NSCLC). In this work, we studied the anticancer effects and the underlying mechanisms of combination of benzerazide hydrocholoride (Benz), a hexokinase 2 (HK2) inhibitor and 64, a pyruvate dehydrogenase kinase 1 (PDK1) inhibitor, in several NSCLC cell lines. We found that combination of Benz and 64 exhibited strong synergistic anticancer effects in NCI-H1975, HCC827, NCI-H1299 and SK-LU-1 cell lines. With this combination treatment, we observed changes of certain mechanistic determinants associated with metabolic stress caused by glycolysis restriction, such as mitochondrial membrane potential depolarization, overproduction of reactive oxygen species [1], activation of AMPK and down-regulation of mTOR, which contributed to enhanced apoptosis. Moreover, Benz and 64 together significantly suppressed the tumor growth in HCC827 cell mouse xenograft model. Taken together, our study may suggest that combined inhibition of HK2 and PDK1 using Benz and 64 could be a viable anticancer strategy for NSCLC.

Keywords:  Cancer metabolism; Combination therapy; HK2; NSCLC; PDK1

DOI:  https://doi.org/10.1016/j.yexcr.2023.113830
Am J Physiol Cell Physiol. 2023 Oct 30.

The iron chelator and OXPHOS inhibitor VLX600 induces mitophagy and an autophagy-dependent type of cell death in glioblastoma cells.

Lisa Reisbeck, Benedikt Linder, Georg Tascher, Süleyman Bozkurt, Katharina J Weber, Christel Herold-Mende, Sjoerd van Wijk, Rolf Marschalek, Liliana Schaefer, Christian Münch, Donat Kögel.

  Induction of alternative, non-apoptotic cell death programs such as cell-lethal autophagy and mitophagy represent possible strategies to combat glioblastoma (GBM). Here we report that VLX600, a novel iron chelator and oxidative phosphorylation (OXPHOS) inhibitor, induces a caspase-independent type of cell death that is partially rescued in adherent U251 ATG5/7 (autophagy related 5/7) knockout (KO) GBM cells and NCH644 ATG5/7 knockdown (KD) glioma stem-like cells (GSCs), suggesting that VLX600 induces an autophagy-dependent cell death (ADCD) in GBM. This ADCD is accompanied by decreased oxygen consumption, increased expression/mitochondrial localization of BNIP3 (BCL2 interacting protein 3) and BNIP3L (BCL2 interacting protein 3 like), the induction of mitophagy as demonstrated by diminished levels of mitochondrial marker proteins (e.g. COX4I1 (cytochrome c oxidase subunit 4I1)) and the mitoKeima assay as well as increased histone H3 and H4 lysine tri-methylation. Further, the extracellular addition of iron is able to significantly rescue VLX600-induced cell death and mitophagy, pointing out an important role of iron metabolism for GBM cell homeostasis. Interestingly, VLX600 is also able to completely eliminate NCH644 GSC tumors in an organotypic brain slice transplantation model. Our data support the therapeutic concept of ADCD induction in GBM and suggest that VLX600 may be an interesting novel drug candidate for the treatment of this tumor.

Keywords:  autophagy; brain tumor; iron metabolism; mitochondrial respiration; non-apoptotic cell death

DOI:  https://doi.org/10.1152/ajpcell.00293.2023
Invest Ophthalmol Vis Sci. 2023 Nov 01. 64(14): 4

Medium Depth Influences O2 Availability and Metabolism in Human RPE Cultures.

Daniel T Hass, Qitao Zhang, Gillian A Autterson, Richard A Bryan, James B Hurley, Jason M L Miller.

Purpose: Retinal pigment epithelium (RPE) oxidative metabolism is critical for normal retinal function and is often studied in cell culture systems. Here, we show that conventional culture media volumes dramatically impact O2 availability, limiting oxidative metabolism. We suggest optimal conditions to ensure cultured RPE is in a normoxic environment permissive to oxidative metabolism.
Methods: We altered the availability of O2 to human primary and induced pluripotent stem cell-derived RPE cultures directly via a hypoxia chamber or indirectly via the amount of medium over cells. We measured oxygen consumption rates (OCRs), glucose consumption, lactate production, 13C6-glucose and 13C5-glutamine flux, hypoxia inducible factor 1α (HIF-1α) stability, intracellular lipid droplets after a lipid challenge, transepithelial electrical resistance, cell morphology, and pigmentation.
Results: Medium volumes commonly employed during RPE culture limit diffusion of O2 to cells, triggering hypoxia, activating HIF-1α, limiting OCR, and dramatically altering cell metabolism, with only minor effects on typical markers of RPE health. Media volume effects on O2 availability decrease acetyl-CoA utilization, increase glycolysis and reductive carboxylation, and alter the size and number of intracellular lipid droplets under lipid-rich conditions.
Conclusions: Despite having little impact on visible and typical markers of RPE culture health, media volume dramatically affects RPE physiology "under the hood." As RPE-centric diseases like age-related macular degeneration involve oxidative metabolism, RPE cultures need to be optimized to study such diseases. We provide guidelines for optimal RPE culture volumes that balance ample nutrient availability from larger media volumes with adequate O2 availability seen with smaller media volumes.

DOI: https://doi.org/10.1167/iovs.64.14.4
bioRxiv. 2023 Oct 20. pii: 2023.10.17.562750. [Epub ahead of print]

HIF-1 inactivation empowers HIF-2 to drive hypoxia adaptation in aggressive forms of medulloblastoma.

J Contenti, Y Guo, M Larcher, L Mirabal-Ortega, M Rouleau, M Irondelle, V Tiroille, A Mazzu, V Duranton-Tanneur, F Pedeutour, I Ben-Sahra, C Lago, G Leva, L Tiberi, G Robert, C Pouponnot, F Bost, N M Mazure.

Medulloblastoma (MB) is the most prevalent brain cancer in children. Four subgroups of MB have been identified; of these, Group 3 is the most metastatic. Its genetics and biology remain less clear than the other groups, and it has a poor prognosis and few effective treatments available. Tumor hypoxia and the resulting metabolism are known to be important in the growth and survival of tumors but, to date, have been only minimally explored in MB. Here we show that Group 3 MB tumors do not depend on the canonical transcription factor hypoxia-inducible factor-1α (HIF-1α) to mount an adaptive response to hypoxia. We discovered that HIF-1α is rendered inactive either through post-translational methylation, preventing its nuclear localization specifically in Group 3 MB, or by a low expression that prevents modulation of HIF-target genes. Strikingly, we found that HIF-2 takes over the role of HIF-1 in the nucleus and promotes the activation of hypoxia-dependent anabolic pathways. The exclusion of HIF-1 from the nucleus in Group 3 MB cells enhances the reliance on HIF-2's transcriptional role, making it a viable target for potential anticancer strategies. By combining pharmacological inhibition of HIF-2α with the use of metformin, a mitochondrial complex I inhibitor to block respiration, we effectively induced Group 3 MB cell death, surpassing the effectiveness observed in Non-Group 3 MB cells. Overall, the unique dependence of MB cells, but not normal cells, on HIF-2-mediated anabolic metabolism presents an appealing therapeutic opportunity for treating Group 3 MB patients with minimal toxicity.

DOI: https://doi.org/10.1101/2023.10.17.562750
Cancer Res. 2023 11 01. 83(21): 3493-3494

Molecular Mechanism of Fasting-Mimicking Diet in Inhibiting Colorectal Cancer Progression: Implications for Immune Therapy and Metabolic Regulation.

Clancy O Bush, Rachel J Perry.

Recently, fasting-mimicking diet and caloric restriction have been shown to improve antitumor immunity. In this issue of Cancer Research, Zhong and colleagues provide insights into the molecular mechanism of fasting-mimicking diet-mediated metabolic reprogramming in colorectal cancer progression. The authors performed comprehensive mechanistic experiments in mouse models to show that fasting-mimicking diet prevents colorectal cancer progression by lowering intratumoral IgA+ B cells by accelerating fatty acid oxidation to inhibit B-cell IgA class switching. In addition, they found that fatty acid oxidation-dependent acetylation prevents IgA class switching and that IgA+ B cells interfere with the anticancer effects of fasting-mimicking diet in colorectal cancer. Overall, their study establishes that fasting-mimicking diet has the potential to activate anticancer immunity and to induce tumor regression in colorectal cancer. See related article by Zhong et al., p. 3529.

DOI: https://doi.org/10.1158/0008-5472.CAN-23-2257
Biochim Biophys Acta Mol Basis Dis. 2023 Oct 26. pii: S0925-4439(23)00288-0. [Epub ahead of print] 166922

Reactive oxygen species in colorectal cancer adjuvant therapies.

Yang Zhang, Mengqiu Hao, Xuyang Yang, Su Zhang, Junhong Han, Ziqiang Wang, Hai-Ning Chen.

  Colorectal cancer (CRC), a prevalent global malignancy, often necessitates adjuvant therapies such as chemotherapy, radiotherapy, targeted therapy, and immunotherapy to mitigate tumor burden in advanced stages. The efficacy of these therapies is significantly influenced by reactive oxygen species (ROS). Previous research underscores the pivotal role of ROS in gut pathology, targeted therapy, and drug resistance. ROS-mediated CRC adjuvant therapies encompass a myriad of mechanisms, including cell death and proliferation, survival and cell cycle, DNA damage, metabolic reprogramming, and angiogenesis. Preliminary clinical trials have begun to unveil the potential of ROS-manipulating therapy in enhancing CRC adjuvant therapies. This review aims to provide a comprehensive synthesis of studies exploring the role of ROS in CRC adjuvant therapies.

Keywords:  Adjuvant therapies; Antioxidant; Colorectal cancer; Oxidative stress; Reactive oxygen species

DOI:  https://doi.org/10.1016/j.bbadis.2023.166922
Cancer Res. 2023 Oct 31.

Metabolomic rewiring promotes endocrine therapy resistance in breast cancer.

Songyeon Ahn, Jun Hyoung Park, Sandra L Grimm, Danthasinghe Waduge Badrajee Piyarathna, Tagari Samanta, Vasanta Putluri, Dereck Mezquita, Suzanne A W Fuqua, Nagireddy Putluri, Cristian Coarfa, Benny Abraham Kaipparettu.

Approximately one-third of endocrine-treated women with estrogen receptor-alpha positive (ER+) breast cancers (BC) are at risk of recurrence due to intrinsic or acquired resistance. Thus, it is vital to understand the mechanisms underlying endocrine therapy resistance in ER+ BC to improve patient treatment. Mitochondrial fatty acid β-oxidation (FAO) has been shown to be a major metabolic pathway in triple-negative BC (TNBC) that can activate Src signaling. Here, we found metabolic reprogramming that increases FAO in ER+ BC as a mechanism of resistance to endocrine therapy. A metabolically relevant, integrated gene signature was derived from transcriptomic, metabolomic, and lipidomic analyses in TNBC cells following inhibition of the FAO rate-limiting enzyme carnitine palmitoyl transferase 1 (CPT1), and this TNBC-derived signature was significantly associated with endocrine resistance in ER+ BC patients. Molecular, genetic, and metabolomic experiments identified activation of AMPK-FAO-oxidative phosphorylation (OXPHOS) signaling in endocrine-resistant ER+ BC. CPT1 knockdown or treatment with FAO inhibitors in vitro and in vivo significantly enhanced the response of ER+ BC cells to endocrine therapy. Consistent with the previous findings in TNBC, endocrine therapy-induced FAO activated the Src pathway in ER+ BC. Src inhibitors suppressed the growth of endocrine-resistant tumors, and the efficacy could be further enhanced by metabolic priming with CPT1 inhibition. Collectively, this study developed and applied a TNBC-derived signature to reveal that metabolic reprogramming to FAO activates the Src pathway to drive endocrine resistance in ER+ BC.

DOI: https://doi.org/10.1158/0008-5472.CAN-23-0184
Free Radic Biol Med. 2023 Oct 26. pii: S0891-5849(23)01084-5. [Epub ahead of print]209(Pt 2): 211-227

Small-molecule redox modulators with anticancer activity: A comprehensive mechanistic update.

Chinmay Pal.

  The pursuit of effective anticancer therapies has led to a burgeoning interest in the realm of redox modulation. This review provides a comprehensive exploration of the intricate mechanisms by which diverse anticancer molecules leverage redox pathways for therapeutic intervention. Redox modulation, encompassing the fine balance of oxidation-reduction processes within cells, has emerged as a pivotal player in cancer treatment. This review delves into the multifaceted mechanisms of action employed by various anticancer compounds, including small molecules and natural products, to disrupt cancer cell proliferation and survival. Beginning with an examination of the role of redox signaling in cancer development and resistance, the review highlights how aberrant redox dynamics can fuel tumorigenesis. It then meticulously dissects the strategies employed by anticancer agents to induce oxidative stress, perturb redox equilibrium, and trigger apoptosis within cancer cells. Furthermore, the review explores the challenges and potential side effects associated with redox-based treatments, along with the development of novel redox-targeted agents. In summary, this review offers a profound understanding of the dynamic interplay between redox modulation and anticancer molecules, presenting promising avenues to revolutionize cancer therapy and enhance patient outcomes.

Keywords:  Apoptosis; Cancer; Oxidative stress; Reactive oxygen species; Small-molecule

DOI:  https://doi.org/10.1016/j.freeradbiomed.2023.10.406
Nat Cancer. 2023 Oct 30.

Imetelstat-mediated alterations in fatty acid metabolism to induce ferroptosis as a therapeutic strategy for acute myeloid leukemia.

Claudia Bruedigam, Amy H Porter, Axia Song, Gerjanne Vroeg In de Wei, Thomas Stoll, Jasmin Straube, Leanne Cooper, Guidan Cheng, Vivian F S Kahl, Alexander P Sobinoff, Victoria Y Ling, Billy Michael Chelliah Jebaraj, Yashaswini Janardhanan, Rohit Haldar, Laura J Bray, Lars Bullinger, Florian H Heidel, Glen A Kennedy, Michelle M Hill, Hilda A Pickett, Omar Abdel-Wahab, Gunter Hartel, Steven W Lane.

Telomerase enables replicative immortality in most cancers including acute myeloid leukemia (AML). Imetelstat is a first-in-class telomerase inhibitor with clinical efficacy in myelofibrosis and myelodysplastic syndromes. Here, we develop an AML patient-derived xenograft resource and perform integrated genomics, transcriptomics and lipidomics analyses combined with functional genetics to identify key mediators of imetelstat efficacy. In a randomized phase II-like preclinical trial in patient-derived xenografts, imetelstat effectively diminishes AML burden and preferentially targets subgroups containing mutant NRAS and oxidative stress-associated gene expression signatures. Unbiased, genome-wide CRISPR/Cas9 editing identifies ferroptosis regulators as key mediators of imetelstat efficacy. Imetelstat promotes the formation of polyunsaturated fatty acid-containing phospholipids, causing excessive levels of lipid peroxidation and oxidative stress. Pharmacological inhibition of ferroptosis diminishes imetelstat efficacy. We leverage these mechanistic insights to develop an optimized therapeutic strategy using oxidative stress-inducing chemotherapy to sensitize patient samples to imetelstat causing substantial disease control in AML.

DOI: https://doi.org/10.1038/s43018-023-00653-5
medRxiv. 2023 Oct 19. pii: 2023.10.16.23297053. [Epub ahead of print]

Probing Human Heart TCA Cycle Metabolism and Response to Glucose Load using Hyperpolarized [2- 13 C]Pyruvate MR Spectroscopy.

Hsin-Yu Chen, Jeremy W Gordon, Nicholas Dwork, Brian T Chung, Andrew Riselli, Sanjay Sivalokanathan, Robert A Bok, James B Slater, Daniel B Vigneron, M Roselle Abraham, Peder E Z Larson.

Introduction: The normal heart has remarkable metabolic flexibility that permits rapid switching between mitochondrial glucose oxidation and fatty acid (FA) oxidation to generate ATP. Loss of metabolic flexibility has been implicated in the genesis of contractile dysfunction seen in cardiomyopathy. Metabolic flexibility has been imaged in experimental models, using hyperpolarized (HP) [2- 13 C]pyruvate MRI, which enables interrogation of metabolites that reflect tricarboxylic acid (TCA) cycle flux in cardiac myocytes. This study aimed to develop methods, demonstrate feasibility for [2- 13 C]pyruvate MRI in the human heart for the first time, and assess cardiac metabolic flexibility.
Methods: Good Manufacturing Practice [2- 13 C]pyruvic acid was polarized in a 5T polarizer for 2.5-3 hours. Following dissolution, QC parameters of HP pyruvate met all safety and sterility criteria for pharmacy release, prior to administration to study subjects. Three healthy subjects each received two HP injections and MR scans, first under fasting conditions, followed by oral glucose load. A 5cm axial slab-selective spectroscopy approach was prescribed over the left ventricle and acquired at 3s intervals on a 3T clinical MRI scanner.
Results: The study protocol which included HP substrate injection, MR scanning and oral glucose load, was performed safely without adverse events. Key downstream metabolites of [2- 13 C]pyruvate metabolism in cardiac myocytes include the glycolytic derivative [2- 13 C]lactate, TCA-associated metabolite [5- 13 C]glutamate, and [1- 13 C]acetylcarnitine, catalyzed by carnitine acetyltransferase (CAT). After glucose load, 13 C-labeling of lactate, glutamate, and acetylcarnitine from 13 C-pyruvate increased by 39.3%, 29.5%, and 114%, respectively in the three subjects, that could result from increases in lactate dehydrogenase (LDH), pyruvate dehydrogenase (PDH), and CAT enzyme activity as well as TCA cycle flux (glucose oxidation).
Conclusions: HP [2- 13 C]pyruvate imaging is safe and permits non-invasive assessment of TCA cycle intermediates and the acetyl buffer, acetylcarnitine, which is not possible using HP [1- 13 C]pyruvate. Cardiac metabolite measurement in the fasting/fed states provides information on cardiac metabolic flexibility and the acetylcarnitine pool.

DOI: https://doi.org/10.1101/2023.10.16.23297053
World J Clin Cases. 2023 Sep 26. 11(27): 6318-6326

Characteristics of amino acid metabolism in colorectal cancer.

Fen Xu, Hong-Liang Jiang, Wei-Wei Feng, Chen Fu, Jiang-Chang Zhou.

  In recent years, metabolomics research has become a hot spot in the screening and treatment of cancer. It is a popular technique for the quantitative characterization of small molecular compounds in biological cells, tissues, organs or organisms. Further study of the tumor revealed that amino acid changes may occur early in the tumor. The rapid growth and metabolism required for survival result in tumors exhibiting an increased demand for amino acids. An abundant supply of amino acids is important for cancer to maintain its proliferative driving force. Changes in amino acid metabolism can be used to screen malignant tumors and improve therapeutic outcomes. Therefore, it is particularly important to study the characteristics of amino acid metabolism in colorectal cancer. This article reviews several specific amino acid metabolism characteristics in colorectal cancer.

Keywords:  Amino acid metabolism; Colorectal cancer; Glutamine; Metabolomics

DOI:  https://doi.org/10.12998/wjcc.v11.i27.6318
Breast Cancer. 2023 Nov 02.

SLC38A5 promotes glutamine metabolism and inhibits cisplatin chemosensitivity in breast cancer.

Xiaowei Shen, Ganggang Wang, Hua He, Ping Shang, Bin Yan, Xiaoliang Wang, Weixing Shen.

   BACKGROUND: Solute carrier family 38 member 5 (SLC38A5), as an amino acid transporter, play a vital role in cellular biological processes. In this study, we analyzed the function of SLC38A5 and its potential mechanism in breast cancer (BC) progression.
METHODS: The expression of SLC38A5 in cancer and adjacent-normal tissues was analyzed by qRT-PCR and Western blot, and its correlation with patient prognosis was analyzed. The immunohistochemical staining of cancer tissues and adjacent-normal tissues was performed on SLC38A5-positive specimens. BC mice were successfully applied to examine the role of SLC38A5 on tumor proliferation using the CCK-8 assay. In BC cells and mouse tumor tissues, SLC38A5 and PCNA expression were determined by Western blotting.
RESULTS: The study found that SLC38A5 was highly expressed in BC patients and associated with a poor survival. SLC38A5 silencing inhibited BC cell viability and glutamine uptake. In addition, SLC38A5 overexpression promoted BC cell viability via the glutamine metabolism. SLC38A5 inhibited cisplatin chemosensitivity in BC cells. Importantly, SLC38A5 silencing inhibited tumor growth in vivo.
CONCLUSION: Our findings suggest that SLC38A5 enhances BC cell viability by glutamine metabolism, inhibits the chemical sensitivity of cisplatin in BC cells, and promotes tumor growth, emphasizing the clinical relevance of SLC38A5 in BC management as a novel potential therapeutic target.

Keywords:  Breast cancer; Cisplatin chemosensitivity; Glutamine metabolism; SLC38A5

DOI:  https://doi.org/10.1007/s12282-023-01516-8
PLoS One. 2023 ;18(11): e0286660

Real-time resolution studies of the regulation of pyruvate-dependent lactate metabolism by hexokinases in single cells.

Scott John, Guillaume Calmettes, Shili Xu, Bernard Ribalet.

Lactate is a mitochondrial substrate for many tissues including neuron, muscle, skeletal and cardiac, as well as many cancer cells, however little is known about the processes that regulate its utilization in mitochondria. Based on the close association of Hexokinases (HK) with mitochondria, and the known cardio-protective role of HK in cardiac muscle, we have investigated the regulation of lactate and pyruvate metabolism by hexokinases (HKs), utilizing wild-type HEK293 cells and HEK293 cells in which the endogenous HKI and/or HKII have been knocked down to enable overexpression of wild type and mutant HKs. To assess the real-time changes in intracellular lactate levels the cells were transfected with a lactate specific FRET probe. In the HKI/HKII double knockdown cells, addition of extracellular pyruvate caused a large and sustained decrease in lactate. This decrease was rapidly reversed upon inhibition of the malate aspartate shuttle by aminooxyacetate, or inhibition of mitochondrial oxidative respiration by NaCN. These results suggest that in the absence of HKs, pyruvate-dependent activation of the TCA cycle together with the malate aspartate shuttle facilitates lactate transformation into pyruvate and its utilization by mitochondria. With replacement by overexpression of HKI or HKII the cellular response to pyruvate and NaCN was modified. With either hexokinase present, both the decrease in lactate due to the addition of pyruvate and the increase following addition of NaCN were either transient or suppressed altogether. Blockage of the pentose phosphate pathway with the inhibitor 6-aminonicotinamide (6-AN), abolished the effects of HK replacement. These results suggest that blocking of the malate aspartate shuttle by HK may involve activation of the pentose phosphate pathway and increased NADPH production.

DOI: https://doi.org/10.1371/journal.pone.0286660
FASEB J. 2023 Dec;37(12): e23280

A practical perspective on how to develop, implement, execute, and reproduce high-resolution respirometry experiments: The physiologist's guide to an Oroboros O2k.

Maureen A Walsh, Robert V Musci, Robert A Jacobs, Karyn L Hamilton.

  The development of high-resolution respirometry (HRR) has greatly expanded the analytical scope to study mitochondrial respiratory control relative to specific tissue/cell types across various metabolic states. Specifically, the Oroboros Oxygraph 2000 (O2k) is a common tool for measuring rates of mitochondrial respiration and is the focus of this perspective. The O2k platform is amenable for answering numerous bioenergetic questions. However, inherent variability with HRR-derived data, both within and amongst users, can impede progress in bioenergetics research. Therefore, we advocate for several vital considerations when planning and conducting O2k experiments to ultimately enhance transparency and reproducibility across laboratories. In this perspective, we offer guidance for best practices of mitochondrial preparation, protocol selection, and measures to increase reproducibility. The goal of this perspective is to propagate the use of the O2k, enhance reliability and validity for both new and experienced O2k users, and provide a reference for peer reviewers.

Keywords:  Oroboros O2k; bioenergetics; isolated mitochondria; mitochondria; permeabilized fibers; protocol development

DOI:  https://doi.org/10.1096/fj.202301644RR
Science. 2023 Nov 02. eadf4154

Autoregulatory control of mitochondrial glutathione homeostasis.

Yuyang Liu, Shanshan Liu, Anju Tomar, Frederick S Yen, Gokhan Unlu, Nathalie Ropek, Ross A Weber, Ying Wang, Artem Khan, Mark Gad, Junhui Peng, Erdem Terzi, Hanan Alwaseem, Alexandra E Pagano, Søren Heissel, Henrik Molina, Benjamin Allwein, Timothy C Kenny, Richard L Possemato, Li Zhao, Richard K Hite, Ekaterina V Vinogradova, Sheref S Mansy, Kıvanç Birsoy.

Mitochondria must maintain adequate amounts of metabolites for protective and biosynthetic functions. However, how mitochondria sense the abundance of metabolites and regulate metabolic homeostasis is not well understood. We focused on glutathione (GSH), a critical redox metabolite in mitochondria and identified a feedback mechanism that controls its abundance through the mitochondrial GSH transporter, SLC25A39. Under physiological conditions, SLC25A39 is rapidly degraded by a mitochondrial protease, AFG3L2. Depletion of GSH dissociates AFG3L2 from SLC25A39, causing a compensatory increase in mitochondrial GSH uptake. Genetic and proteomic analysis identified a putative iron-sulfur cluster in the matrix-facing loop of SLC25A39 to be essential for this regulation, coupling mitochondrial iron homeostasis to GSH import. Altogether, our work revealed a paradigm for the autoregulatory control of metabolic homeostasis in organelles.

DOI: https://doi.org/10.1126/science.adf4154
Nat Commun. 2023 Nov 01. 14(1): 6966

Cancer-associated fibroblasts actively compress cancer cells and modulate mechanotransduction.

Jorge Barbazan, Carlos Pérez-González, Manuel Gómez-González, Mathieu Dedenon, Sophie Richon, Ernest Latorre, Marco Serra, Pascale Mariani, Stéphanie Descroix, Pierre Sens, Xavier Trepat, Danijela Matic Vignjevic.

During tumor progression, cancer-associated fibroblasts (CAFs) accumulate in tumors and produce an excessive extracellular matrix (ECM), forming a capsule that enwraps cancer cells. This capsule acts as a barrier that restricts tumor growth leading to the buildup of intratumoral pressure. Combining genetic and physical manipulations in vivo with microfabrication and force measurements in vitro, we found that the CAFs capsule is not a passive barrier but instead actively compresses cancer cells using actomyosin contractility. Abrogation of CAFs contractility in vivo leads to the dissipation of compressive forces and impairment of capsule formation. By mapping CAF force patterns in 3D, we show that compression is a CAF-intrinsic property independent of cancer cell growth. Supracellular coordination of CAFs is achieved through fibronectin cables that serve as scaffolds allowing force transmission. Cancer cells mechanosense CAF compression, resulting in an altered localization of the transcriptional regulator YAP and a decrease in proliferation. Our study unveils that the contractile capsule actively compresses cancer cells, modulates their mechanical signaling, and reorganizes tumor morphology.

DOI: https://doi.org/10.1038/s41467-023-42382-4
Acta Haematol. 2023 Oct 31.

Non-immunotherapy approaches for Relapsed or Refractory AML: an update for 2024.

Shira Buchrits, Ofir Wolach.

BACKGROUND: Relapsed or refractory (R/R) acute myeloid leukemia (AML) is a challenging, high-risk, clinical scenario with a dismal outcome. Recent insights on the genetic, epigenetic, and metabolic events that drive clonal progression and the advent of novel therapies resulted in the incorporation of several new targeted therapies, alone or in combination, in the R/R setting with the aim of improving response rates and survival. Herein we review current challenges and future opportunities with non-immunotherapeutic approaches to treat R/R AML.
SUMMARY: Inhibitors of FLT3 and IDH 1/2 are now FDA-approved for patients with R/R disease and corresponding mutations. These agents are also used in combination with intensive and low-intensity platforms in an attempt to improve response and survival. Several targeted agents are currently being tested alone or in combination in early-phase trials. These include drugs that target apoptotic pathways, drugs that interfere with key survival pathways of the R/R leukemic cell as well as therapies aimed towards the leukemia marrow microenvironment. Menin inhibitors are a promising class of active drugs in NPM1 and KMT2A-rearranged AML. Key-messages: Several new targeted therapies, immunologic and non-immunologic are being studied and are moving through pre-clinical and clinical pipelines. Significant remaining challenges include the development of synergistic combination therapies tailored to the specific biology and clinical context of the patient, and re-defining the role and timing of allogeneic transplantation in patients with R/R disease.

DOI: https://doi.org/10.1159/000534897
Front Pharmacol. 2023 ;14 1275000

Natural compounds as lactate dehydrogenase inhibitors: potential therapeutics for lactate dehydrogenase inhibitors-related diseases.

Jung Ho Han, Eun-Ji Lee, Wonyoung Park, Ki-Tae Ha, Hwan-Suck Chung.

  Lactate dehydrogenase (LDH) is a crucial enzyme involved in energy metabolism and present in various cells throughout the body. Its diverse physiological functions encompass glycolysis, and its abnormal activity is associated with numerous diseases. Targeting LDH has emerged as a vital approach in drug discovery, leading to the identification of LDH inhibitors among natural compounds, such as polyphenols, alkaloids, and terpenoids. These compounds demonstrate therapeutic potential against LDH-related diseases, including anti-cancer effects. However, challenges concerning limited bioavailability, poor solubility, and potential toxicity must be addressed. Combining natural compounds with LDH inhibitors has led to promising outcomes in preclinical studies. This review highlights the promise of natural compounds as LDH inhibitors for treating cancer, cardiovascular, and neurodegenerative diseases.

Keywords:  LDH inhibitor; cancer; cardiovascular disease; lactate dehydrogenase; natural compound; neurodegenerative disease; pharmacological effect

DOI:  https://doi.org/10.3389/fphar.2023.1275000
Blood Adv. 2023 Oct 31. pii: bloodadvances.2023010786. [Epub ahead of print]

The 'non-essential' amino acid cysteine is required to prevent ferroptosis in acute myeloid leukemia.

Alan Cunningham, Lieve Oudejans, Marjan Geugien, Diego A Pereira-Martins, Albertus Tj Wierenga, Ayşegül Erdem, Dominique Sternadt, Gerwin A Huls, Jan Jacob Schuringa.

Cysteine is a non-essential amino acid required for protein synthesis, the generation of the anti-oxidant glutathione and for synthesizing the non-proteinogenic amino acid taurine. Here, we highlight the broad sensitivity of leukemic stem and progenitor cells to cysteine depletion. By CRISPR/Cas9-mediated knockout of cystathionine-γ-Lysase (CTH), the cystathionine to cysteine converting enzyme, and by metabolite supplementation studies upstream of cysteine, we functionally prove that cysteine is not synthesized from methionine in acute myeloid leukemia (AML) cells. Therefore, while perhaps nutritionally non-essential, cysteine must be imported for survival of these specific cell types. Depletion of cyst(e)ine increased reactive oxygen species (ROS) levels and cell death was induced predominantly as a consequence of glutathione deprivation. NADPH oxidase (NOX) inhibition strongly rescued viability following cysteine depletion, highlighting this as an important source of ROS in AML. ROS-induced cell death was mediated via ferroptosis, and inhibition of GPX4, which functions to reduce lipid peroxides, was also highly toxic and we therefore propose that GPX4 is likely key in mediating the antioxidant activity of glutathione. In line, inhibition of the ROS scavenger thioredoxin reductase with Auranofin also impaired cell viability, whereby we find that in particular OXPHOS-driven AML subtypes are highly dependent on thioredoxin-mediated protection against ferroptosis. While inhibition of the cystine importer xCT with Sulfasalazine was ineffective as a monotherapy, its combination with L-buthionine-sulfoximine (BSO) further improved AML ferroptosis induction. We propose the combination of either Sulfasalazine or anti-oxidant machinery inhibitors along with ROS inducers such as BSO or chemotherapy for further pre-clinical testing.

DOI: https://doi.org/10.1182/bloodadvances.2023010786
bioRxiv. 2023 Oct 17. pii: 2023.10.13.562280. [Epub ahead of print]

Clinically relevant humanized mouse models of metastatic prostate cancer to evaluate cancer therapies.

Raymond J Kostlan, John T Phoenix, Audris Budreika, Marina G Ferrari, Neetika Khurana, Jae Eun Cho, Kristin Juckette, Brooke L McCollum, Russell Moskal, Rahul Mannan, Yuanyuan Qiao, Donald J Vander Griend, Arul M Chinnaiyan, Steven Kregel.

There is tremendous need for improved prostate cancer (PCa) models. The mouse prostate does not spontaneously form tumors and is anatomically and developmentally different from the human prostate. Engineered mouse models lack the heterogeneity of human cancer and rarely establish metastatic growth. Human xenografts represent an alternative but rely on an immunocompromised host. Accordingly, we generated PCa murine xenograft models with an intact human immune system (huNOG and huNOG-EXL mice) to test whether humanizing tumor-immune interactions would improve modeling of metastatic PCa and the impact of hormonal and immunotherapies. These mice maintain multiple human cell lineages, including functional human T-cells and myeloid cells. In 22Rv1 xenografts, subcutaneous tumor size was not significantly altered across conditions; however, metastasis to secondary sites differed in castrate huNOG vs background-matched immunocompromised mice treated with enzalutamide (enza). VCaP xenograft tumors showed decreases in growth with enza and anti-Programed-Death-1 treatments in huNOG mice, and no effect was seen with treatment in NOG mice. Enza responses in huNOG and NOG mice were distinct and associated with increased T-cells within tumors of enza treated huNOG mice, and increased T-cell activation. In huNOG-EXL mice, which support human myeloid development, there was a strong population of immunosuppressive regulatory T-cells and Myeloid-Derived-Suppressor-Cells (MDSCs), and enza treatment showed no difference in metastasis. Results illustrate, to our knowledge, the first model of human PCa that metastasizes to clinically relevant locations, has an intact human immune system, responds appropriately to standard-of-care hormonal therapies, and can model both an immunosuppressive and checkpoint-inhibition responsive immune microenvironment.

DOI: https://doi.org/10.1101/2023.10.13.562280