bims-camemi 2024-04-21 papers

bims-camemi

Biomed News

on Mitochondrial metabolism in cancer

Issue of 2024–04–21
39 papers selected by
Christian Frezza, Universität zu Köln

The role of lipoylation in mitochondrial adaptation to methionine restriction.
Diet and Cancer Metabolism.
LXR/CD38 activation drives cholesterol-induced macrophage senescence and neurodegeneration via NAD+ depletion.
Mitochondrial energy state controls AMPK-mediated foraging behavior in C. elegans.
The emerging importance of the α-keto acid dehydrogenase complexes in serving as intracellular and intercellular signaling platforms for the regulation of metabolism.
Activation of hepatic acetyl-CoA carboxylase by S-nitrosylation in response to diet.
The intersection of frailty and metabolism.
Onco-Circuit Addiction and Onco-Nutrient mTORC1 Signaling Vulnerability in a Model of Aggressive T Cell Malignancy.
Von Hippel Lindau tumor suppressor controls m6A-dependent gene expression in renal tumorigenesis.
Serine enrichment in tumors promotes regulatory T cell accumulation through sphinganine-mediated regulation of c-Fos.
Iron regulates the quiescence of naive CD4 T cells by controlling mitochondria and cellular metabolism.
De novo purine metabolism is a metabolic vulnerability of cancers with low p16 expression.
Redox regulation of macrophages.
Deuterium metabolic imaging differentiates glioblastoma metabolic subtypes and detects early response to chemoradiotherapy.
Metabolic programming of organ-specific natural killer cell responses.
Bisbiguanide analogs induce mitochondrial stress to inhibit lung cancer cell invasion.
OMA1 clears traffic jam in TOM tunnel in mammals.
The genetic landscape of a metabolic interaction.
Iron Is Critical for Mucosal-Associated Invariant T Cell Metabolism and Effector Functions.
Cross-link assisted spatial proteomics to map sub-organelle proteomes and membrane protein topologies.
Context-dependent roles for ubiquitous mitochondrial creatine kinase CKMT1 in breast cancer progression.
VHL loss reprograms the immune landscape to promote an inflammatory myeloid microenvironment in renal tumorigenesis.
Next questions in autophagy.
GPR1 and CMKLR1 control lipid metabolism to support development of clear cell renal cell carcinoma.
Single-mitosis dissection of acute and chronic DNA mutagenesis and repair.
Enhanced ROS Production in Mitochondria from Prematurely Aging mtDNA Mutator Mice.
CRISPR-Cas9 screening identifies KRAS-induced COX-2 as a driver of immunotherapy resistance in lung cancer.
Therapeutic exploitation of ferroptosis.
Nuclear receptor corepressors non-canonically drive glucocorticoid receptor-dependent activation of hepatic gluconeogenesis.
Free ribosomal proteins as culprits for nucleolar stress.
Rapid HPLC method reveals dynamic shifts in coenzyme Q redox state.
Potassium rhythms couple the circadian clock to the cell cycle.
SARS-CoV-2 Mitochondrial Metabolic and Epigenomic Reprogramming in COVID-19.
Clonal expansion in normal tissues.
ABCG2 and SLC1A5 functionally interact to rewire metabolism and confer a survival advantage to cancer cells under oxidative stress.
Macropinocytosis at the crossroad between nutrient scavenging and metabolism in cancer.
Recharacterization of RSL3 reveals that the selenoproteome is a druggable target in colorectal cancer.
TAK1 inhibition leads to RIPK1-dependent apoptosis in immune-activated cancers.
The microbiota drives diurnal rhythms in tryptophan metabolism in the stressed gut.

Bioessays. 2024 Apr 14. e2300218

The role of lipoylation in mitochondrial adaptation to methionine restriction.

Jingyuan Xue, Cunqi Ye.

  Dietary methionine restriction (MR) is associated with a spectrum of health-promoting benefits. Being conducive to prevention of chronic diseases and extension of life span, MR can activate integrated responses at metabolic, transcriptional, and physiological levels. However, how the mitochondria of MR influence metabolic phenotypes remains elusive. Here, we provide a summary of cellular functions of methionine metabolism and an overview of the current understanding of effector mechanisms of MR, with a focus on the aspect of mitochondria-mediated responses. We propose that mitochondria can sense and respond to MR through a modulatory role of lipoylation, a mitochondrial protein modification sensitized by MR.

Keywords:  cellular metabolism; lipidomics; metabolomics; methioinine metabolism; phospholipid

DOI:  https://doi.org/10.1002/bies.202300218
Cold Spring Harb Perspect Med. 2024 Apr 15. pii: a041549. [Epub ahead of print]

Diet and Cancer Metabolism.

Jason W Locasale, Marcus D Goncalves, Maira Di Tano, Guillermo Burgos-Barragan.

Diet and exercise are modifiable lifestyle factors known to have a major influence on metabolism. Clinical practice addresses diseases of altered metabolism such as diabetes or hypertension by altering these factors. Despite enormous public interest, there are limited defined diet and exercise regimens for cancer patients. Nevertheless, the molecular basis of cancer has converged over the past 15 years on an essential role for altered metabolism in cancer. However, our understanding of the molecular mechanisms that underlie the impact of diet and exercise on cancer metabolism is in its very early stages. In this work, we propose conceptual frameworks for understanding the consequences of diet and exercise on cancer cell metabolism and tumor biology and also highlight recent developments. By advancing our mechanistic understanding, we also discuss actionable ways that such interventions could eventually reach the mainstay of both medical oncology and cancer control and prevention.

DOI: https://doi.org/10.1101/cshperspect.a041549
Cell Rep. 2024 Apr 15. pii: S2211-1247(24)00430-3. [Epub ahead of print] 114102

LXR/CD38 activation drives cholesterol-induced macrophage senescence and neurodegeneration via NAD+ depletion.

Ryo Terao, Tae Jun Lee, Jason Colasanti, Charles W Pfeifer, Joseph B Lin, Andrea Santeford, Keitaro Hase, Shinobu Yamaguchi, Daniel Du, Brian S Sohn, Yo Sasaki, Mitsukuni Yoshida, Rajendra S Apte.

  Although dysregulated cholesterol metabolism predisposes aging tissues to inflammation and a plethora of diseases, the underlying molecular mechanism remains poorly defined. Here, we show that metabolic and genotoxic stresses, convergently acting through liver X nuclear receptor, upregulate CD38 to promote lysosomal cholesterol efflux, leading to nicotinamide adenine dinucleotide (NAD+) depletion in macrophages. Cholesterol-mediated NAD+ depletion induces macrophage senescence, promoting key features of age-related macular degeneration (AMD), including subretinal lipid deposition and neurodegeneration. NAD+ augmentation reverses cellular senescence and macrophage dysfunction, preventing the development of AMD phenotype. Genetic and pharmacological senolysis protect against the development of AMD and neurodegeneration. Subretinal administration of healthy macrophages promotes the clearance of senescent macrophages, reversing the AMD disease burden. Thus, NAD+ deficit induced by excess intracellular cholesterol is the converging mechanism of macrophage senescence and a causal process underlying age-related neurodegeneration.

Keywords:  CD38; CP: Immunology; CP: Metabolism; NAD(+); NMN; age-related macular degeneration; cellular senescence; cholesterol efflux; neurodegeneration; nicotinamide adenine dinucleotide; nicotinamide mononucleotide

DOI:  https://doi.org/10.1016/j.celrep.2024.114102
Sci Adv. 2024 Apr 19. 10(16): eadm8815

Mitochondrial energy state controls AMPK-mediated foraging behavior in C. elegans.

Anežka Vodičková, Annika Müller-Eigner, Chidozie N Okoye, Andrew P Bischer, Jacob Horn, Shon A Koren, Nada Ahmed Selim, Andrew P Wojtovich.

Organisms surveil and respond to their environment using behaviors entrained by metabolic cues that reflect food availability. Mitochondria act as metabolic hubs and at the center of mitochondrial energy production is the protonmotive force (PMF), an electrochemical gradient generated by metabolite consumption. The PMF serves as a central integrator of mitochondrial status, but its role in governing metabolic signaling is poorly understood. We used optogenetics to dissipate the PMF in Caenorhabditis elegans tissues to test its role in food-related behaviors. Our data demonstrate that PMF reduction in the intestine is sufficient to initiate locomotor responses to acute food deprivation. This behavioral adaptation requires the cellular energy regulator AMP-activated protein kinase (AMPK) in neurons, not in the intestine, and relies on mitochondrial dynamics and axonal trafficking. Our results highlight a role for intestinal PMF as an internal metabolic cue, and we identify a bottom-up signaling axis through which changes in the PMF trigger AMPK activity in neurons to promote foraging behavior.

DOI: https://doi.org/10.1126/sciadv.adm8815
Redox Biol. 2024 Apr 10. pii: S2213-2317(24)00131-9. [Epub ahead of print]72 103155

The emerging importance of the α-keto acid dehydrogenase complexes in serving as intracellular and intercellular signaling platforms for the regulation of metabolism.

Ryan J Mailloux.

The α-keto acid dehydrogenase complex (KDHc) class of mitochondrial enzymes is composed of four members: pyruvate dehydrogenase (PDHc), α-ketoglutarate dehydrogenase (KGDHc), branched-chain keto acid dehydrogenase (BCKDHc), and 2-oxoadipate dehydrogenase (OADHc). These enzyme complexes occupy critical metabolic intersections that connect monosaccharide, amino acid, and fatty acid metabolism to Krebs cycle flux and oxidative phosphorylation (OxPhos). This feature also imbues KDHc enzymes with the heightened capacity to serve as platforms for propagation of intracellular and intercellular signaling. KDHc enzymes serve as a source and sink for mitochondrial hydrogen peroxide (mtH2O2), a vital second messenger used to trigger oxidative eustress pathways. Notably, deactivation of KDHc enzymes through reversible oxidation by mtH2O2 and other electrophiles modulates the availability of several Krebs cycle intermediates and related metabolites which serve as powerful intracellular and intercellular messengers. The KDHc enzymes also play important roles in the modulation of mitochondrial metabolism and epigenetic programming in the nucleus through the provision of various acyl-CoAs, which are used to acylate proteinaceous lysine residues. Intriguingly, nucleosomal control by acylation is also achieved through PDHc and KGDHc localization to the nuclear lumen. In this review, I discuss emerging concepts in the signaling roles fulfilled by the KDHc complexes. I highlight their vital function in serving as mitochondrial redox sensors and how this function can be used by cells to regulate the availability of critical metabolites required in cell signaling. Coupled with this, I describe in detail how defects in KDHc function can cause disease states through the disruption of cell redox homeodynamics and the deregulation of metabolic signaling. Finally, I propose that the intracellular and intercellular signaling functions of the KDHc enzymes are controlled through the reversible redox modification of the vicinal lipoic acid thiols in the E2 subunit of the complexes.

DOI: https://doi.org/10.1016/j.redox.2024.103155
J Lipid Res. 2024 Apr 17. pii: S0022-2275(24)00047-6. [Epub ahead of print] 100542

Activation of hepatic acetyl-CoA carboxylase by S-nitrosylation in response to diet.

Nicholas M Venetos, Colin T Stomberski, Zhaoxia Qian, Richard T Premont, Jonathan S Stamler.

  Nitric oxide (NO), produced primarily by nitric oxide synthase (NOS) enzymes, is known to influence energy metabolism by stimulating fat uptake and oxidation. The effects of NO on de novo lipogenesis, however, are less clear. Here we demonstrate that hepatic expression of eNOS is reduced following prolonged administration of a hypercaloric high-fat diet. This results in marked reduction in the amount of S-nitrosylation of liver proteins including notably Acetyl-CoA Carboxylase (ACC), the rate-limiting enzyme in de novo lipogenesis. We further show that ACC S-nitrosylation markedly increases enzymatic activity. Diminished eNOS expression and ACC S-nitrosylation may thus represent a physiological adaptation to caloric excess by constraining lipogenesis. Our findings demonstrate that S-nitrosylation of liver proteins is subject to dietary control and suggest that de novo lipogenesis is coupled to dietary and metabolic conditions through ACC S-nitrosylation.

Keywords:  Acetyl-CoA Carboxylase; Cell signaling; Dietary fat; Lipogenesis; Liver; S-nitrosylation; Triglycerides

DOI:  https://doi.org/10.1016/j.jlr.2024.100542
Cell Metab. 2024 Apr 05. pii: S1550-4131(24)00091-3. [Epub ahead of print]

The intersection of frailty and metabolism.

Manish Mishra, Judy Wu, Alice E Kane, Susan E Howlett.

  On average, aging is associated with unfavorable changes in cellular metabolism, which are the processes involved in the storage and expenditure of energy. However, metabolic dysregulation may not occur to the same extent in all older individuals as people age at different rates. Those who are aging rapidly are at increased risk of adverse health outcomes and are said to be "frail." Here, we explore the links between frailty and metabolism, including metabolic contributors and consequences of frailty. We examine how metabolic diseases may modify the degree of frailty in old age and suggest that frailty may predispose toward metabolic disease. Metabolic interventions that can mitigate the degree of frailty in people are reviewed. New treatment strategies developed in animal models that are poised for translation to humans are also considered. We suggest that maintaining a youthful metabolism into older age may be protective against frailty.

Keywords:  frailty index; frailty phenotype; metabolic dysregulation; metabolic syndrome; mouse models; protein restriction

DOI:  https://doi.org/10.1016/j.cmet.2024.03.012
bioRxiv. 2024 Apr 04. pii: 2024.04.03.587917. [Epub ahead of print]

Onco-Circuit Addiction and Onco-Nutrient mTORC1 Signaling Vulnerability in a Model of Aggressive T Cell Malignancy.

Xinxin Wang, Andrew E Cornish, Mytrang H Do, Julia S Brunner, Ting-Wei Hsu, Zijian Xu, Isha Malik, Chaucie Edwards, Kristelle J Capistrano, Xian Zhang, Mark H Ginsberg, Lydia W S Finley, Megan S Lim, Steven M Horwitz, Ming O Li.

How genetic lesions drive cell transformation and whether they can be circumvented without compromising function of non-transformed cells are enduring questions in oncology. Here we show that in mature T cells-in which physiologic clonal proliferation is a cardinal feature- constitutive MYC transcription and Tsc1 loss in mice modeled aggressive human malignancy by reinforcing each other's oncogenic programs. This cooperation was supported by MYC-induced large neutral amino acid transporter chaperone SLC3A2 and dietary leucine, which in synergy with Tsc1 deletion overstimulated mTORC1 to promote mitochondrial fitness and MYC protein overexpression in a positive feedback circuit. A low leucine diet was therapeutic even in late-stage disease but did not hinder T cell immunity to infectious challenge, nor impede T cell transformation driven by constitutive nutrient mTORC1 signaling via Depdc5 loss. Thus, mTORC1 signaling hypersensitivity to leucine as an onco-nutrient enables an onco-circuit, decoupling pathologic from physiologic utilization of nutrient acquisition pathways.

DOI: https://doi.org/10.1101/2024.04.03.587917
J Clin Invest. 2024 Apr 15. pii: e175703. [Epub ahead of print]134(8):

Von Hippel Lindau tumor suppressor controls m6A-dependent gene expression in renal tumorigenesis.

Cheng Zhang, Miaomiao Yu, Austin J Hepperla, Zhao Zhang, Rishi Raj, Hua Zhong, Jin Zhou, Lianxin Hu, Jun Fang, Hongyi Liu, Qian Liang, Liwei Jia, Chengheng Liao, Sichuan Xi, Jeremy M Simon, Kexin Xu, Zhijie Liu, Yunsun Nam, Payal Kapur, Qing Zhang.

  N6-Methyladenosine (m6A) is the most abundant posttranscriptional modification, and its contribution to cancer evolution has recently been appreciated. Renal cancer is the most common adult genitourinary cancer, approximately 85% of which is accounted for by the clear cell renal cell carcinoma (ccRCC) subtype characterized by VHL loss. However, it is unclear whether VHL loss in ccRCC affects m6A patterns. In this study, we demonstrate that VHL binds and promotes METTL3/METTL14 complex formation while VHL depletion suppresses m6A modification, which is distinctive from its canonical E3 ligase role. m6A RNA immunoprecipitation sequencing (RIP-Seq) coupled with RNA-Seq allows us to identify a selection of genes whose expression may be regulated by VHL-m6A signaling. Specifically, PIK3R3 is identified to be a critical gene whose mRNA stability is regulated by VHL in a m6A-dependent but HIF-independent manner. Functionally, PIK3R3 depletion promotes renal cancer cell growth and orthotopic tumor growth while its overexpression leads to decreased tumorigenesis. Mechanistically, the VHL-m6A-regulated PIK3R3 suppresses tumor growth by restraining PI3K/AKT activity. Taken together, we propose a mechanism by which VHL regulates m6A through modulation of METTL3/METTL14 complex formation, thereby promoting PIK3R3 mRNA stability and protein levels that are critical for regulating ccRCC tumorigenesis.

Keywords:  Oncology; Tumor suppressors

DOI:  https://doi.org/10.1172/JCI175703
Sci Immunol. 2024 Apr 19. 9(94): eadg8817

Serine enrichment in tumors promotes regulatory T cell accumulation through sphinganine-mediated regulation of c-Fos.

Sicong Ma, Roger Sandhoff, Xiu Luo, Fuwei Shang, Qiaozhen Shi, Zhaolong Li, Jingxia Wu, Yanan Ming, Frank Schwarz, Alaa Madi, Nina Weisshaar, Alessa Mieg, Marvin Hering, Ferdinand Zettl, Xin Yan, Kerstin Mohr, Nora Ten Bosch, Zhe Li, Gernot Poschet, Hans-Reimer Rodewald, Nina Papavasiliou, Xi Wang, Pu Gao, Guoliang Cui.

CD4+ regulatory T (Treg) cells accumulate in the tumor microenvironment (TME) and suppress the immune system. Whether and how metabolite availability in the TME influences Treg cell differentiation is not understood. Here, we measured 630 metabolites in the TME and found that serine and palmitic acid, substrates required for the synthesis of sphingolipids, were enriched. A serine-free diet or a deficiency in Sptlc2, the rate-limiting enzyme catalyzing sphingolipid synthesis, suppressed Treg cell accumulation and inhibited tumor growth. Sphinganine, an intermediate metabolite in sphingolipid synthesis, physically interacted with the transcription factor c-Fos. Sphinganine c-Fos interactions enhanced the genome-wide recruitment of c-Fos to regions near the transcription start sites of target genes including Pdcd1 (encoding PD-1), which promoted Pdcd1 transcription and increased inducible Treg cell differentiation in vitro in a PD-1-dependent manner. Thus, Sptlc2-mediated sphingolipid synthesis translates the extracellular information of metabolite availability into nuclear signals for Treg cell differentiation and limits antitumor immunity.

DOI: https://doi.org/10.1126/sciimmunol.adg8817
Proc Natl Acad Sci U S A. 2024 Apr 23. 121(17): e2318420121

Iron regulates the quiescence of naive CD4 T cells by controlling mitochondria and cellular metabolism.

Ajay Kumar, Chenxian Ye, Afia Nkansah, Thomas Decoville, Garrett M Fogo, Peter Sajjakulnukit, Mack B Reynolds, Li Zhang, Osbourne Quaye, Young-Ah Seo, Thomas H Sanderson, Costas A Lyssiotis, Cheong-Hee Chang.

  In response to an immune challenge, naive T cells undergo a transition from a quiescent to an activated state acquiring the effector function. Concurrently, these T cells reprogram cellular metabolism, which is regulated by iron. We and others have shown that iron homeostasis controls proliferation and mitochondrial function, but the underlying mechanisms are poorly understood. Given that iron derived from heme makes up a large portion of the cellular iron pool, we investigated iron homeostasis in T cells using mice with a T cell-specific deletion of the heme exporter, FLVCR1 [referred to as knockout (KO)]. Our finding revealed that maintaining heme and iron homeostasis is essential to keep naive T cells in a quiescent state. KO naive CD4 T cells exhibited an iron-overloaded phenotype, with increased spontaneous proliferation and hyperactive mitochondria. This was evidenced by reduced IL-7R and IL-15R levels but increased CD5 and Nur77 expression. Upon activation, however, KO CD4 T cells have defects in proliferation, IL-2 production, and mitochondrial functions. Iron-overloaded CD4 T cells failed to induce mitochondrial iron and exhibited more fragmented mitochondria after activation, making them susceptible to ferroptosis. Iron overload also led to inefficient glycolysis and glutaminolysis but heightened activity in the hexosamine biosynthetic pathway. Overall, these findings highlight the essential role of iron in controlling mitochondrial function and cellular metabolism in naive CD4 T cells, critical for maintaining their quiescent state.

Keywords:  heme; iron; mitochondria; tonic signaling

DOI:  https://doi.org/10.1073/pnas.2318420121
Cancer Res Commun. 2024 Apr 16.

De novo purine metabolism is a metabolic vulnerability of cancers with low p16 expression.

Naveen Kumar Tangudu, Raquel Buj, Hui Wang, Jiefei Wang, Aidan R Cole, Apoorva Uboveja, Richard Fang, Amandine Amalric, Baixue Yang, Adam Chatoff, Claudia V Crispim, Peter Sajjakulnukit, Maureen A Lyons, Kristine Cooper, Nadine Hempel, Costas A Lyssiotis, Uma R Chandran, Nathaniel W Snyder, Katherine M Aird.

p16 is a tumor suppressor encoded by the CDKN2A gene whose expression is lost in ~50% of all human cancers. In its canonical role, p16 inhibits the G1-S phase cell cycle progression through suppression of cyclin dependent kinases. Interestingly, p16 also has roles in metabolic reprogramming, and we previously published that loss of p16 promotes nucleotide synthesis via the pentose phosphate pathway. However, the broader impact of p16/CDKN2A loss on other nucleotide metabolic pathways and potential therapeutic targets remains unexplored. Using CRISPR KO libraries in isogenic human and mouse melanoma cell lines, we determined several nucleotide metabolism genes essential for the survival of cells with loss of p16/CDKN2A. Consistently, many of these genes are upregulated in melanoma cells with p16 knockdown or endogenously low CDKN2A expression. We determined that cells with low p16/CDKN2A expression are sensitive to multiple inhibitors of de novo purine synthesis, including anti-folates. Finally, tumors with p16 knockdown were more sensitive to the anti-folate methotrexate in vivo than control tumors. Together, our data provide evidence to reevaluate the utility of these drugs in patients with p16/CDKN2Alow tumors as loss of p16/CDKN2A may provide a therapeutic window for these agents.

DOI: https://doi.org/10.1158/2767-9764.CRC-23-0450
Redox Biol. 2024 Mar 12. pii: S2213-2317(24)00099-5. [Epub ahead of print]72 103123

Redox regulation of macrophages.

Nhien Tran, Evanna L Mills.

Redox signaling, a mode of signal transduction that involves the transfer of electrons from a nucleophilic to electrophilic molecule, has emerged as an essential regulator of inflammatory macrophages. Redox reactions are driven by reactive oxygen/nitrogen species (ROS and RNS) and redox-sensitive metabolites such as fumarate and itaconate, which can post-translationally modify specific cysteine residues in target proteins. In the past decade our understanding of how ROS, RNS, and redox-sensitive metabolites control macrophage function has expanded dramatically. In this review, we discuss the latest evidence of how ROS, RNS, and metabolites regulate macrophage function and how this is dysregulated with disease. We highlight the key tools to assess redox signaling and important questions that remain.

DOI: https://doi.org/10.1016/j.redox.2024.103123
Cancer Res. 2024 Apr 18.

Deuterium metabolic imaging differentiates glioblastoma metabolic subtypes and detects early response to chemoradiotherapy.

Jacob Chen Ming Low, Jianbo Cao, Friederike Hesse, Alan J Wright, Anastasia Tsyben, Islam Alshamleh, Richard Mair, Kevin M Brindle.

Metabolic subtypes of glioblastoma have different prognoses and responses to treatment. Deuterium metabolic imaging with 2H-labeled substrates is a potential approach to stratify patients into metabolic subtypes for targeted treatment. Here, we used 2H magnetic resonance spectroscopy (MRS) and spectroscopic imaging (MRSI) measurements of [6,6'-2H2]glucose metabolism to identify metabolic subtypes and their responses to chemoradiotherapy in patient-derived glioblastoma xenografts in vivo. The metabolism of patient-derived cells was first characterized in vitro by measuring the oxygen consumption rate, a marker of mitochondrial TCA cycle activity, as well as the extracellular acidification rate and 2H-labeled lactate production from [6,6'-2H2]glucose, which are markers of glycolytic activity. Two cell lines representative of a glycolytic subtype and two representative of a mitochondrial subtype were identified. 2H MRS and MRSI measurements showed similar concentrations of 2H-labeled glucose from [6,6'-2H2]glucose in all four tumor models when implanted orthotopically in mice. The glycolytic subtypes showed higher concentrations of 2H-labeled lactate than the mitochondrial subtypes and normal-appearing brain tissue, whereas the mitochondrial subtypes showed more glutamate/glutamine labeling, a surrogate for TCA cycle activity, than the glycolytic subtypes and normal-appearing brain tissue. The response of the tumors to chemoradiation could be detected within 24 hours of treatment completion, with the mitochondrial subtypes showing a decrease in both 2H-labeled glutamate/glutamine and lactate concentrations and glycolytic tumors showing a decrease in 2H-labeled lactate concentration. This technique has the potential to be used clinically for treatment selection and early detection of treatment response.

DOI: https://doi.org/10.1158/0008-5472.CAN-23-2552
Immunol Rev. 2024 Apr 17.

Metabolic programming of organ-specific natural killer cell responses.

Rebecca B Delconte, Joseph C Sun.

  Cells of the mammalian innate immune system have evolved to protect the host from various environmental or internal insults and injuries which perturb the homeostatic state of the organism. Among the lymphocytes of the innate immune system are natural killer (NK) cells, which circulate and survey host tissues for signs of stress, including infection or transformation. NK cells rapidly eliminate damaged cells in the blood or within tissues through secretion of cytolytic machinery and production of proinflammatory cytokines. To perform these effector functions while traversing between the blood and tissues, patrolling NK cells require sufficient fuel to meet their energetic demands. Here, we highlight the ability of NK cells to metabolically adapt across tissues, during times of nutrient deprivation and within tumor microenvironments. Whether at steady state, or during viral infection and cancer, NK cells readily shift their nutrient uptake and usage in order to maintain metabolism, survival, and function.

Keywords:  NK cells; cancer; immunity; immunometabolism

DOI:  https://doi.org/10.1111/imr.13333
iScience. 2024 Apr 19. 27(4): 109591

Bisbiguanide analogs induce mitochondrial stress to inhibit lung cancer cell invasion.

Christina M Knippler, Jamie L Arnst, Isaac E Robinson, Veronika Matsuk, Tala O Khatib, R Donald Harvey, Mala Shanmugam, Janna K Mouw, Haian Fu, Thota Ganesh, Adam I Marcus.

  Targeting cancer metabolism to limit cellular energy and metabolite production is an attractive therapeutic approach. Here, we developed analogs of the bisbiguanide, alexidine, to target lung cancer cell metabolism and assess a structure-activity relationship (SAR). The SAR led to the identification of two analogs, AX-4 and AX-7, that limit cell growth via G1/G0 cell-cycle arrest and are tolerated in vivo with favorable pharmacokinetics. Mechanistic evaluation revealed that AX-4 and AX-7 induce potent mitochondrial defects; mitochondrial cristae were deformed and the mitochondrial membrane potential was depolarized. Additionally, cell metabolism was rewired, as indicated by reduced oxygen consumption and mitochondrial ATP production, with an increase in extracellular lactate. Importantly, AX-4 and AX-7 impacted overall cell behavior, as these compounds reduced collective cell invasion. Taken together, our study establishes a class of bisbiguanides as effective mitochondria and cell invasion disrupters, and proposes bisbiguanides as promising approaches to limiting cancer metastasis.

Keywords:  Cancer; Cell biology; Cellular physiology

DOI:  https://doi.org/10.1016/j.isci.2024.109591
J Cell Biol. 2024 May 06. pii: e202403190. [Epub ahead of print]223(5):

OMA1 clears traffic jam in TOM tunnel in mammals.

Shiori Sekine, Yusuke Sekine.

Using an engineered mitochondrial clogger, Krakowczyk et al. (https://doi.org/10.1083/jcb.202306051) identified the OMA1 protease as a critical component that eliminates import failure at the TOM translocase in mammalian cells, providing a novel quality control mechanism that is distinct from those described in yeast.

DOI: https://doi.org/10.1083/jcb.202403190
Nat Commun. 2024 Apr 18. 15(1): 3351

The genetic landscape of a metabolic interaction.

Thuy N Nguyen, Christine Ingle, Samuel Thompson, Kimberly A Reynolds.

While much prior work has explored the constraints on protein sequence and evolution induced by physical protein-protein interactions, the sequence-level constraints emerging from non-binding functional interactions in metabolism remain unclear. To quantify how variation in the activity of one enzyme constrains the biochemical parameters and sequence of another, we focus on dihydrofolate reductase (DHFR) and thymidylate synthase (TYMS), a pair of enzymes catalyzing consecutive reactions in folate metabolism. We use deep mutational scanning to quantify the growth rate effect of 2696 DHFR single mutations in 3 TYMS backgrounds under conditions selected to emphasize biochemical epistasis. Our data are well-described by a relatively simple enzyme velocity to growth rate model that quantifies how metabolic context tunes enzyme mutational tolerance. Together our results reveal the structural distribution of epistasis in a metabolic enzyme and establish a foundation for the design of multi-enzyme systems.

DOI: https://doi.org/10.1038/s41467-024-47671-0
J Immunol. 2024 Apr 15. pii: ji2300649. [Epub ahead of print]

Iron Is Critical for Mucosal-Associated Invariant T Cell Metabolism and Effector Functions.

Eimear K Ryan, Christy Clutter, Conor De Barra, Benjamin J Jenkins, Simon O'Shaughnessy, Odhrán K Ryan, Chloe McKenna, Helen M Heneghan, Fiona Walsh, David K Finlay, Linda V Sinclair, Nicholas Jones, Daniel T Leung, Donal O'Shea, Andrew E Hogan.

Mucosal-Associated Invariant T (MAIT) cells are a population of innate T cells that play a critical role in host protection against bacterial and viral pathogens. Upon activation, MAIT cells can rapidly respond via both TCR-dependent and -independent mechanisms, resulting in robust cytokine production. The metabolic and nutritional requirements for optimal MAIT cell effector responses are still emerging. Iron is an important micronutrient and is essential for cellular fitness, in particular cellular metabolism. Iron is also critical for many pathogenic microbes, including those that activate MAIT cells. However, iron has not been investigated with respect to MAIT cell metabolic or functional responses. In this study, we show that human MAIT cells require exogenous iron, transported via CD71 for optimal metabolic activity in MAIT cells, including their production of ATP. We demonstrate that restricting iron availability by either chelating environmental iron or blocking CD71 on MAIT cells results in impaired cytokine production and proliferation. These data collectively highlight the importance of a CD71-iron axis for human MAIT cell metabolism and functionality, an axis that may have implications in conditions where iron availability is limited.

DOI: https://doi.org/10.4049/jimmunol.2300649
Nat Commun. 2024 Apr 17. 15(1): 3290

Cross-link assisted spatial proteomics to map sub-organelle proteomes and membrane protein topologies.

Ying Zhu, Kerem Can Akkaya, Julia Ruta, Nanako Yokoyama, Cong Wang, Max Ruwolt, Diogo Borges Lima, Martin Lehmann, Fan Liu.

The functions of cellular organelles and sub-compartments depend on their protein content, which can be characterized by spatial proteomics approaches. However, many spatial proteomics methods are limited in their ability to resolve organellar sub-compartments, profile multiple sub-compartments in parallel, and/or characterize membrane-associated proteomes. Here, we develop a cross-link assisted spatial proteomics (CLASP) strategy that addresses these shortcomings. Using human mitochondria as a model system, we show that CLASP can elucidate spatial proteomes of all mitochondrial sub-compartments and provide topological insight into the mitochondrial membrane proteome. Biochemical and imaging-based follow-up studies confirm that CLASP allows discovering mitochondria-associated proteins and revising previous protein sub-compartment localization and membrane topology data. We also validate the CLASP concept in synaptic vesicles, demonstrating its applicability to different sub-cellular compartments. This study extends the scope of cross-linking mass spectrometry beyond protein structure and interaction analysis towards spatial proteomics, and establishes a method for concomitant profiling of sub-organelle and membrane proteomes.

DOI: https://doi.org/10.1038/s41467-024-47569-x
Cell Rep. 2024 Apr 12. pii: S2211-1247(24)00449-2. [Epub ahead of print]43(4): 114121

Context-dependent roles for ubiquitous mitochondrial creatine kinase CKMT1 in breast cancer progression.

Vinay Ayyappan, Nicole M Jenkinson, Caitlin M Tressler, Zheqiong Tan, Menglin Cheng, Xinyi Elaine Shen, Alejandro Guerrero, Kanchan Sonkar, Ruoqing Cai, Oluwatobi Adelaja, Sujayita Roy, Alan Meeker, Pedram Argani, Kristine Glunde.

  Metabolic reprogramming is a hallmark of cancer, enabling cancer cells to rapidly proliferate, invade, and metastasize. We show that creatine levels in metastatic breast cancer cell lines and secondary metastatic tumors are driven by the ubiquitous mitochondrial creatine kinase (CKMT1). We discover that, while CKMT1 is highly expressed in primary tumors and promotes cell viability, it is downregulated in metastasis. We further show that CKMT1 downregulation, as seen in breast cancer metastasis, drives up mitochondrial reactive oxygen species (ROS) levels. CKMT1 downregulation contributes to the migratory and invasive potential of cells by ROS-induced upregulation of adhesion and degradative factors, which can be reversed by antioxidant treatment. Our study thus reconciles conflicting evidence about the roles of metabolites in the creatine metabolic pathway in breast cancer progression and reveals that tight, context-dependent regulation of CKMT1 expression facilitates cell viability, cell migration, and cell invasion, which are hallmarks of metastatic spread.

Keywords:  CKMT1; CP: Cancer; CP: Metabolism; breast cancer; creatine; metabolism; metastasis; reactive oxygen species

DOI:  https://doi.org/10.1016/j.celrep.2024.114121
J Clin Invest. 2024 Apr 15. pii: e173934. [Epub ahead of print]134(8):

VHL loss reprograms the immune landscape to promote an inflammatory myeloid microenvironment in renal tumorigenesis.

Melissa M Wolf, Matthew Z Madden, Emily N Arner, Jackie E Bader, Xiang Ye, Logan Vlach, Megan L Tigue, Madelyn D Landis, Patrick B Jonker, Zaid Hatem, KayLee K Steiner, Dakim K Gaines, Bradley I Reinfeld, Emma S Hathaway, Fuxue Xin, M Noor Tantawy, Scott M Haake, Eric Jonasch, Alexander Muir, Vivian L Weiss, Kathryn E Beckermann, W Kimryn Rathmell, Jeffrey C Rathmell.

  Clear cell renal cell carcinoma (ccRCC) is characterized by dysregulated hypoxia signaling and a tumor microenvironment (TME) highly enriched in myeloid and lymphoid cells. Loss of the von Hippel Lindau (VHL) gene is a critical early event in ccRCC pathogenesis and promotes stabilization of HIF. Whether VHL loss in cancer cells affects immune cells in the TME remains unclear. Using Vhl WT and Vhl-KO in vivo murine kidney cancer Renca models, we found that Vhl-KO tumors were more infiltrated by immune cells. Tumor-associated macrophages (TAMs) from Vhl-deficient tumors demonstrated enhanced in vivo glucose consumption, phagocytosis, and inflammatory transcriptional signatures, whereas lymphocytes from Vhl-KO tumors showed reduced activation and a lower response to anti-programmed cell death 1 (anti-PD-1) therapy in vivo. The chemokine CX3CL1 was highly expressed in human ccRCC tumors and was associated with Vhl deficiency. Deletion of Cx3cl1 in cancer cells decreased myeloid cell infiltration associated with Vhl loss to provide a mechanism by which Vhl loss may have contributed to the altered immune landscape. Here, we identify cancer cell-specific genetic features that drove environmental reprogramming and shaped the tumor immune landscape, with therapeutic implications for the treatment of ccRCC.

Keywords:  Cancer; Macrophages; Metabolism; Oncology; T cells

DOI:  https://doi.org/10.1172/JCI173934
Nat Cell Biol. 2024 Apr 19.

Next questions in autophagy.

Ana Maria Cuervo, Zvulun Elazar, Chantell Evans, Liang Ge, Malene Hansen, Marja Jäättelä, Jin Rui Amos Liang, Ben Loos, Noboru Mizushima, Anna Katharina Simon, Sharon Tooze, Tamotsu Yoshimori, Shuhei Nakamura.

DOI: https://doi.org/10.1038/s41556-024-01404-z
Cancer Res. 2024 Apr 19.

GPR1 and CMKLR1 control lipid metabolism to support development of clear cell renal cell carcinoma.

Dazhi Wang, Iqbal Mahmud, Vijay S Thakur, Sze Kiat Tan, Daniel G Isom, David B Lombard, Mark L Gonzalgo, Oleksandr N Kryvenko, Philip L Lorenzi, Vanina T Tcheuyap, James Brugarolas, Scott M Welford.

Clear cell renal cell carcinoma (ccRCC), the most common type of kidney cancer, is largely incurable in the metastatic setting. ccRCC is characterized by excessive lipid accumulation that protects cells from stress and promotes tumor growth, suggesting that the underlying regulators of lipid storage could represent potential therapeutic targets. Here, we evaluated the regulatory roles of GPR1 and CMKLR1, two G-protein coupled receptors of the pro-tumorigenic adipokine chemerin that is involved in ccRCC lipid metabolism. Both genetic and pharmacological suppression of either receptor suppressed lipid formation and induced multiple forms of cell death, including apoptosis, ferroptosis and autophagy, significantly impeding ccRCC growth in cell lines and patient derived xenograft (PDX) models. Comprehensive lipidomic and transcriptomic profiling of receptor competent and depleted cells revealed overlapping and unique signaling of the receptors granting control over triglyceride synthesis, ceramide production, and fatty acid saturation and class production. Mechanistically, the receptors both enforced suppression of the triglyceride lipase ATGL but also demonstrated distinct functions, such as the unique ability of CMKLR1 to control lipid uptake through regulation of SREBP1c and the CD36 scavenger receptor. Treating PDX models with the CMKLR1-targeting small molecule α-NETA led to a dramatic reduction of tumor growth, lipid storage, and clear cell morphology. Together, these findings provide mechanistic insight into lipid regulation in ccRCC and identify a targetable axis at the core of the histological definition of this tumor that could be exploited therapeutically.

DOI: https://doi.org/10.1158/0008-5472.CAN-23-2926
Nat Genet. 2024 Apr 16.

Single-mitosis dissection of acute and chronic DNA mutagenesis and repair.

Paul Adrian Ginno, Helena Borgers, Christina Ernst, Anja Schneider, Mikaela Behm, Sarah J Aitken, Martin S Taylor, Duncan T Odom.

How chronic mutational processes and punctuated bursts of DNA damage drive evolution of the cancer genome is poorly understood. Here, we demonstrate a strategy to disentangle and quantify distinct mechanisms underlying genome evolution in single cells, during single mitoses and at single-strand resolution. To distinguish between chronic (reactive oxygen species (ROS)) and acute (ultraviolet light (UV)) mutagenesis, we microfluidically separate pairs of sister cells from the first mitosis following burst UV damage. Strikingly, UV mutations manifest as sister-specific events, revealing mirror-image mutation phasing genome-wide. In contrast, ROS mutagenesis in transcribed regions is reduced strand agnostically. Successive rounds of genome replication over persisting UV damage drives multiallelic variation at CC dinucleotides. Finally, we show that mutation phasing can be resolved to single strands across the entire genome of liver tumors from F1 mice. This strategy can be broadly used to distinguish the contributions of overlapping cancer relevant mutational processes.

DOI: https://doi.org/10.1038/s41588-024-01712-y
Biochemistry (Mosc). 2024 Feb;89(2): 279-298

Enhanced ROS Production in Mitochondria from Prematurely Aging mtDNA Mutator Mice.

Irina G Shabalina, Daniel Edgar, Natalia Gibanova, Anastasia V Kalinovich, Natasa Petrovic, Mikhail Yu Vyssokikh, Barbara Cannon, Jan Nedergaard.

  An increase in mitochondrial DNA (mtDNA) mutations and an ensuing increase in mitochondrial reactive oxygen species (ROS) production have been suggested to be a cause of the aging process ("the mitochondrial hypothesis of aging"). In agreement with this, mtDNA-mutator mice accumulate a large amount of mtDNA mutations, giving rise to defective mitochondria and an accelerated aging phenotype. However, incongruously, the rates of ROS production in mtDNA mutator mitochondria have generally earlier been reported to be lower - not higher - than in wildtype, thus apparently invalidating the "mitochondrial hypothesis of aging". We have here re-examined ROS production rates in mtDNA-mutator mice mitochondria. Using traditional conditions for measuring ROS (succinate in the absence of rotenone), we indeed found lower ROS in the mtDNA-mutator mitochondria compared to wildtype. This ROS mainly results from reverse electron flow driven by the membrane potential, but the membrane potential reached in the isolated mtDNA-mutator mitochondria was 33 mV lower than that in wildtype mitochondria, due to the feedback inhibition of succinate oxidation by oxaloacetate, and to a lower oxidative capacity in the mtDNA-mutator mice, explaining the lower ROS production. In contrast, in normal forward electron flow systems (pyruvate (or glutamate) + malate or palmitoyl-CoA + carnitine), mitochondrial ROS production was higher in the mtDNA-mutator mitochondria. Particularly, even during active oxidative phosphorylation (as would be ongoing physiologically), higher ROS rates were seen in the mtDNA-mutator mitochondria than in wildtype. Thus, when examined under physiological conditions, mitochondrial ROS production rates are indeed increased in mtDNA-mutator mitochondria. While this does not prove the validity of the mitochondrial hypothesis of aging, it may no longer be said to be negated in this respect. This paper is dedicated to the memory of Professor Vladimir P. Skulachev.

Keywords:  ROS production; aging; membrane potential; mtDNA mutator mice; oxidative phosphorylation; succinate

DOI:  https://doi.org/10.1134/S0006297924020081
Cancer Res. 2024 Apr 18.

CRISPR-Cas9 screening identifies KRAS-induced COX-2 as a driver of immunotherapy resistance in lung cancer.

Jesse Boumelha, Andrea de Castro, Nourdine Bah, Hongui Cha, Sophie de Carné Trécesson, Sareena Rana, Mona Tomaschko, Panayiotis Anastasiou, Edurne Mugarza, Christopher Moore, Robert Goldstone, Philip East, Kevin Litchfield, Se-Hoon Lee, Miriam Molina-Arcas, Julian Downward.

Oncogenic KRAS impairs anti-tumor immune responses. As effective strategies to combine KRAS inhibitors and immunotherapies have so far proven elusive, a better understanding of how oncogenic KRAS drives immune evasion is needed to identify approaches that could sensitize KRAS-mutant lung cancer to immunotherapy. In vivo CRISPR-Cas9 screening in an immunogenic murine lung cancer model identified mechanisms by which oncogenic KRAS promotes immune evasion, most notably via upregulation of immunosuppressive cyclooxygenase-2 (COX-2) in cancer cells. Oncogenic KRAS potently induced COX-2 in both mouse and human lung cancer, which was suppressed using KRAS inhibitors. COX-2 acted via prostaglandin E2 (PGE2) to promote resistance to immune checkpoint blockade (ICB) in lung adenocarcinoma. Targeting COX-2/PGE2 remodeled the tumor microenvironment by inducing pro-inflammatory polarization of myeloid cells and influx of activated cytotoxic CD8+ T cells, which increased the efficacy of ICB. Restoration of COX-2 expression contributed to tumor relapse after prolonged KRAS inhibition. These results provide the rationale for testing COX-2/PGE2 pathway inhibitors in combination with KRASG12C inhibition or ICB in patients with KRAS-mutant lung cancer.

DOI: https://doi.org/10.1158/0008-5472.CAN-23-2627
Biochem Soc Trans. 2024 Apr 17. pii: BST20230550. [Epub ahead of print]

Therapeutic exploitation of ferroptosis.

Magali Walravens, Ine Koeken, Tom Vanden Berghe.

  Pathological breakdown of membrane lipids through excessive lipid peroxidation (LPO) was first described in the mid-20th century and is now recognized as a form of regulated cell death, dubbed ferroptosis. Accumulating evidence unveils how metabolic regulation restrains peroxidation of phospholipids within cellular membranes, thereby impeding ferroptosis execution. Unleashing these metabolic breaks is currently therapeutically explored to sensitize cancers to ferroptosis inducing anti-cancer therapies. Reversely, these natural ferroptotic defense mechanisms can fail resulting in pathological conditions or diseases such as ischemia-reperfusion injury, multi-organ dysfunction, stroke, infarction, or neurodegenerative diseases. This minireview outlines current ferroptosis-inducing anti-cancer strategies and highlights the detection as well as the therapeutic targeting of ferroptosis in preclinical experimental settings. Herein, we also briefly summarize observations related to LPO, iron and redox deregulation in patients that might hint towards ferroptosis as a contributing factor.

Keywords:  cancer; cell death; ferroptosis; ischaemia-reperfusion injury; lipid peroxidation; oxidative stress

DOI:  https://doi.org/10.1042/BST20230550
Nat Metab. 2024 Apr 15.

Nuclear receptor corepressors non-canonically drive glucocorticoid receptor-dependent activation of hepatic gluconeogenesis.

Amy K Hauck, Rashid Mehmood, Bryce J Carpenter, Maxwell T Frankfurter, Michael C Tackenberg, Shin-Ichi Inoue, Maria K Krieg, Fathima N Cassim Bawa, Mohit K Midha, Delaine M Zundell, Kirill Batmanov, Mitchell A Lazar.

Nuclear receptor corepressors (NCoRs) function in multiprotein complexes containing histone deacetylase 3 (HDAC3) to alter transcriptional output primarily through repressive chromatin remodelling at target loci1-5. In the liver, loss of HDAC3 causes a marked hepatosteatosis largely because of de-repression of genes involved in lipid metabolism6,7; however, the individual roles and contribution of other complex members to hepatic and systemic metabolic regulation are unclear. Here we show that adult loss of both NCoR1 and NCoR2 (double knockout (KO)) in hepatocytes phenocopied the hepatomegalic fatty liver phenotype of HDAC3 KO. In addition, double KO livers exhibited a dramatic reduction in glycogen storage and gluconeogenic gene expression that was not observed with hepatic KO of individual NCoRs or HDAC3, resulting in profound fasting hypoglycaemia. This surprising HDAC3-independent activation function of NCoR1 and NCoR2 is due to an unexpected loss of chromatin accessibility on deletion of NCoRs that prevented glucocorticoid receptor binding and stimulatory effect on gluconeogenic genes. These studies reveal an unanticipated, non-canonical activation function of NCoRs that is required for metabolic health.

DOI: https://doi.org/10.1038/s42255-024-01029-4
Mol Cell. 2024 Apr 18. pii: S1097-2765(24)00271-5. [Epub ahead of print]84(8): 1400-1402

Free ribosomal proteins as culprits for nucleolar stress.

Ina Huppertz.

Nucleolar stress has been consistently linked to age-related diseases. In this issue, Sirozh et al.1 find that the common molecular signature of nucleolar stress is the accumulation of free ribosomal proteins, which leads to premature aging in mice; however, it can be reversed by mTOR inhibition.

DOI: https://doi.org/10.1016/j.molcel.2024.03.026
J Biol Chem. 2024 Apr 17. pii: S0021-9258(24)01802-7. [Epub ahead of print] 107301

Rapid HPLC method reveals dynamic shifts in coenzyme Q redox state.

Victor Vitvitsky, Roshan Kumar, Jutta Diessl, David A Hanna, Ruma Banerjee.

Ubiquinol or coenzyme Q (CoQ) is a lipid-soluble electron carrier in the respiratory chain and an electron acceptor for various enzymes in metabolic pathways that intersect at this cofactor hub in the mitochondrial inner membrane. The reduced form of CoQ is an antioxidant, which protects against lipid peroxidation. In this study, we have optimized a UV-detected HPLC method for CoQ analysis from biological materials, which involves a rapid single-step extraction into n-propanol followed by direct sample injection onto a column. Using this method, we have measured the oxidized, reduced and total CoQ pools, and monitored shifts in the CoQ redox status in response to cell culture conditions and bioenergetic perturbations. We find that hypoxia or sulfide exposure induces a reductive shift in the intracellular CoQ pool. The effect of hypoxia is however, rapidly reversed by exposure to ambient air. Interventions at different loci in the electron transport chain can induce sizeable redox shifts in the oxidative or reductive direction, depending on whether they are up- or downstream of complex III. We have also used this method to confirm that CoQ levels are higher and more reduced in murine heart versus brain. In summary, the availability of a convenient HPLC-based method described herein, will facilitate studies on CoQ redox dynamics in response to environmental, nutritional and endogenous alterations.

DOI: https://doi.org/10.1016/j.jbc.2024.107301
bioRxiv. 2024 Apr 03. pii: 2024.04.02.587153. [Epub ahead of print]

Potassium rhythms couple the circadian clock to the cell cycle.

Sergio Gil Rodríguez, Priya Crosby, Louise L Hansen, Ellen Grünewald, Andrew D Beale, Rebecca K Spangler, Beverley M Rabbitts, Carrie L Partch, Alessandra Stangherlin, John S O'Neill, Gerben van Ooijen.

Circadian (∼24 h) rhythms are a fundamental feature of life, and their disruption increases the risk of infectious diseases, metabolic disorders, and cancer 1-6 . Circadian rhythms couple to the cell cycle across eukaryotes 7,8 but the underlying mechanism is unknown. We previously identified an evolutionarily conserved circadian oscillation in intracellular potassium concentration, [K + ] i 9,10 . As critical events in the cell cycle are regulated by intracellular potassium 11,12 , an enticing hypothesis is that circadian rhythms in [K + ] i form the basis of this coupling. We used a minimal model cell, the alga Ostreococcus tauri, to uncover the role of potassium in linking these two cycles. We found direct reciprocal feedback between [K + ] i and circadian gene expression. Inhibition of proliferation by manipulating potassium rhythms was dependent on the phase of the circadian cycle. Furthermore, we observed a total inhibition of cell proliferation when circadian gene expression is inhibited. Strikingly, under these conditions a sudden enforced gradient of extracellular potassium was sufficient to induce a round of cell division. Finally, we provide evidence that interactions between potassium and circadian rhythms also influence proliferation in mammalian cells. These results establish circadian regulation of intracellular potassium levels as a primary factor coupling the cell- and circadian cycles across diverse organisms.

DOI: https://doi.org/10.1101/2024.04.02.587153
Pharmacol Res. 2024 Apr 11. pii: S1043-6618(24)00114-2. [Epub ahead of print] 107170

SARS-CoV-2 Mitochondrial Metabolic and Epigenomic Reprogramming in COVID-19.

Joseph W Guarnieri, Jeffrey A Haltom, Yentli E Soto Albrecht, Timothy Lie, Arnold Z Olali, Gabrielle A Widjaja, Sujata S Ranshing, Alessia Angelin, Deborah Murdock, Douglas C Wallace.

  To determine the effects of SARS-CoV-2 infection on cellular metabolism, we conducted an exhaustive survey of the cellular metabolic pathways modulated by SARS-CoV-2 infection and confirmed their importance for SARS-CoV-2 propagation by cataloging the effects of specific pathway inhibitors. This revealed that SARS-CoV-2 strongly inhibits mitochondrial oxidative phosphorylation (OXPHOS) resulting in increased mitochondrial reactive oxygen species (mROS) production. The elevated mROS stabilizes HIF-1α which redirects carbon molecules from mitochondrial oxidation through glycolysis and the pentose phosphate pathway (PPP) to provide substrates for viral biogenesis. mROS also induces the release of mitochondrial DNA (mtDNA) which activates innate immunity. The restructuring of cellular energy metabolism is mediated in part by SARS-CoV-2 Orf8 and Orf10 whose expression restructures nuclear DNA (nDNA) and mtDNA OXPHOS gene expression. These viral proteins likely alter the epigenome, either by directly altering histone modifications or by modulating mitochondrial metabolite substrates of epigenome modification enzymes, potentially silencing OXPHOS gene expression and contributing to long-COVID.

Keywords:  Mitochondria; OXPHOS; SARS-CoV-2; epigenome; gene regulation; inhibitors; metabolism

DOI:  https://doi.org/10.1016/j.phrs.2024.107170
Cancer Sci. 2024 Apr 16.

Clonal expansion in normal tissues.

Hirona Maeda, Nobuyuki Kakiuchi.

  Cancer originates from a single ancestral cell that acquires a driver mutation, which confers a growth or survival advantage, followed by the acquisition of additional driver mutations by descendant cells. Recently, it has become evident that somatic cell mutations accumulate in normal tissues with aging and exposure to environmental factors, such as alcohol, smoking, and UV rays, increases the mutation rate. Clones harboring driver mutations expand with age, leading to tissue remodeling. Lineage analysis of myeloproliferative neoplasms and der(1;16)-positive breast cancer revealed that driver mutations were acquired early in our lives and that the development of cancer takes decades, unveiling the previously unknown early process of cancer development. Evidence that clonal hematopoiesis affects various diseases, including nonneoplastic diseases, highlights the potential role of the identification and functional analysis of mutated clones in unraveling unknown pathologies. In this review, we summarize the recent updates on clonal expansion in normal tissues and the natural history of cancer revealed through lineage analysis of noncancerous and cancerous tissues.

Keywords:  aging; carcinogenesis; clonal evolution; mutation rate; phylogenetic analysis

DOI:  https://doi.org/10.1111/cas.16183
J Biol Chem. 2024 Apr 17. pii: S0021-9258(24)01800-3. [Epub ahead of print] 107299

ABCG2 and SLC1A5 functionally interact to rewire metabolism and confer a survival advantage to cancer cells under oxidative stress.

Jia Shi, Kirk Pabon, Rui Ding, Kathleen W Scotto.

ABCG2, a member of the ABC transporter superfamily, is overexpressed in many human tumors and has long been studied for its ability to export a variety of chemotherapeutic agents, thereby conferring a multidrug resistance (MDR) phenotype. However, several studies have shown that ABCG2 can also confer an MDR-independent survival advantage to tumor cells exposed to stress. While investigating the mechanism by which ABCG2 enhances survival in stressful milieus, we have identified a physical and functional interaction between ABCG2 and SLC1A5, a member of the solute transporter superfamily and the primary transporter of glutamine in cancer cells. This interaction was accompanied by increased glutamine uptake, increased glutaminolysis and rewired cellular metabolism, as evidenced by an increase in key metabolic enzymes and alteration of glutamine-dependent metabolic pathways. Specifically, we observed an increase in glutamine metabolites shuttled to the TCA cycle, an increase in the synthesis of glutathione, accompanied by a decrease in basal levels of reactive oxygen species and a marked increase in cell survival in the face of oxidative stress. Notably, knockdown of SLC1A5 or depletion of exogenous glutamine diminished ABCG2-enhanced autophagy flux, further implicating this solute transporter in ABCG2-mediated cell survival. This is, to our knowledge, the first report of a functionally significant physical interaction between members of the two major transporter superfamilies. Moreover, these observations may underlie the protective role of ABCG2 in cancer cells under duress and suggest a novel role for ABCG2 in the regulation of metabolism in normal and diseased states.

DOI: https://doi.org/10.1016/j.jbc.2024.107299
Curr Opin Cell Biol. 2024 Apr 15. pii: S0955-0674(24)00038-3. [Epub ahead of print]88 102359

Macropinocytosis at the crossroad between nutrient scavenging and metabolism in cancer.

Elena Rainero.

Macropinocytosis (MP), the actin-dependent bulk uptake of extracellular fluids, plays a central role in nutrient scavenging, allowing cancer cells to sustain their growth in the hypoxic and nutrient-deprived microenvironment often found in solid tumours. The lack of soluble nutrients and several oncogenic signalling pathways, with RAS being the most studied, push MP-dependent internalisation of extracellular proteins, which are then digested in the lysosomes, replenishing the intracellular nutrient pools. This review will highlight recent advances in understanding how MP is regulated in hypoxic cancers, how it impinges on chemoresistance, and how different MP cargos facilitate tumour growth. Finally, I will highlight the crosstalk between MP and extracellular matrix receptors.

DOI: https://doi.org/10.1016/j.ceb.2024.102359
bioRxiv. 2024 Apr 01. pii: 2024.03.29.587381. [Epub ahead of print]

Recharacterization of RSL3 reveals that the selenoproteome is a druggable target in colorectal cancer.

Stephen L DeAngelo, Sofia Dziechciarz, Sumeet Solanki, Myungsun Shin, Liang Zhao, Andrii Balia, Marwa O El-Derany, Nupur K Das, Cristina Castillo, Hannah N Bell, Joao A Paulo, Yuezhong Zhang, Nicholas J Rossiter, Elizabeth C McCulla, Jianping He, Indrani Talukder, Zachary T Schafer, Nouri Neamati, Joseph D Mancias, Markos Koutmos, Yatrik M Shah.

Ferroptosis is an iron-dependent, non-apoptotic form of cell death resulting from the accumulation of lipid peroxides. Colorectal cancer (CRC) accumulates high levels of intracellular iron and reactive oxygen species (ROS), thereby sensitizing cells to ferroptosis. The selenoprotein glutathione peroxidase (GPx4) is a key enzyme in the detoxification of lipid peroxides and can be inhibited by the compound (S)-RSL3 ([1S,3R]-RSL3). However, the stereoisomer (R)-RSL3 ([1R,3R]-RSL3), which does not inhibit GPx4, exhibits equipotent activity to (S)-RSL3 across a panel of CRC cell lines. Utilizing CRC cell lines with an inducible knockdown of GPx4, we demonstrate that (S)-RSL3 sensitivity does not align with GPx4 dependency. Subsequently, a biotinylated (S)-RSL3 was then synthesized to perform affinity purification-mass spectrometry (AP-MS), revealing that (S)-RSL3 acts as a pan-inhibitor of the selenoproteome, targeting both the glutathione and thioredoxin peroxidase systems as well as multiple additional selenoproteins. To investigate the therapeutic potential of broadly disrupting the selenoproteome as a therapeutic strategy in CRC, we employed further chemical and genetic approaches to disrupt selenoprotein function. The findings demonstrate that the selenoprotein inhibitor Auranofin can induce ferroptosis and/or oxidative cell death both in-vitro and in-vivo . Consistent with this data we observe that AlkBH8, a tRNA-selenocysteine methyltransferase required for the translational incorporation of selenocysteine, is essential for CRC growth. In summary, our research elucidates the complex mechanisms underlying ferroptosis in CRC and reveals that modulation of the selenoproteome provides multiple new therapeutic targets and opportunities in CRC.

DOI: https://doi.org/10.1101/2024.03.29.587381
Cell Death Dis. 2024 Apr 17. 15(4): 273

TAK1 inhibition leads to RIPK1-dependent apoptosis in immune-activated cancers.

Helene Damhofer, Tülin Tatar, Benjamin Southgate, Scott Scarneo, Karl Agger, Daria Shlyueva, Lene Uhrbom, Gillian M Morrison, Philip F Hughes, Timothy Haystead, Steven M Pollard, Kristian Helin.

Poor survival and lack of treatment response in glioblastoma (GBM) is attributed to the persistence of glioma stem cells (GSCs). To identify novel therapeutic approaches, we performed CRISPR/Cas9 knockout screens and discovered TGFβ activated kinase (TAK1) as a selective survival factor in a significant fraction of GSCs. Loss of TAK1 kinase activity results in RIPK1-dependent apoptosis via Caspase-8/FADD complex activation, dependent on autocrine TNFα ligand production and constitutive TNFR signaling. We identify a transcriptional signature associated with immune activation and the mesenchymal GBM subtype to be a characteristic of cancer cells sensitive to TAK1 perturbation and employ this signature to accurately predict sensitivity to the TAK1 kinase inhibitor HS-276. In addition, exposure to pro-inflammatory cytokines IFNγ and TNFα can sensitize resistant GSCs to TAK1 inhibition. Our findings reveal dependency on TAK1 kinase activity as a novel vulnerability in immune-activated cancers, including mesenchymal GBMs that can be exploited therapeutically.

DOI: https://doi.org/10.1038/s41419-024-06654-1
Cell Rep. 2024 Apr 11. pii: S2211-1247(24)00407-8. [Epub ahead of print]43(4): 114079

The microbiota drives diurnal rhythms in tryptophan metabolism in the stressed gut.

Cassandra E Gheorghe, Sarah-Jane Leigh, Gabriel S S Tofani, Thomaz F S Bastiaanssen, Joshua M Lyte, Elisa Gardellin, Ashokkumar Govindan, Conall Strain, Sonia Martinez-Herrero, Michael S Goodson, Nancy Kelley-Loughnane, John F Cryan, Gerard Clarke.

  Chronic stress disrupts microbiota-gut-brain axis function and is associated with altered tryptophan metabolism, impaired gut barrier function, and disrupted diurnal rhythms. However, little is known about the effects of acute stress on the gut and how it is influenced by diurnal physiology. Here, we used germ-free and antibiotic-depleted mice to understand how microbiota-dependent oscillations in tryptophan metabolism would alter gut barrier function at baseline and in response to an acute stressor. Cecal metabolomics identified tryptophan metabolism as most responsive to a 15-min acute stressor, while shotgun metagenomics revealed that most bacterial species exhibiting rhythmicity metabolize tryptophan. Our findings highlight that the gastrointestinal response to acute stress is dependent on the time of day and the microbiome, with a signature of stress-induced functional alterations in the ileum and altered tryptophan metabolism in the colon.

Keywords:  CP: Metabolism; CP: Microbiology; acute stress; circadian rhythms; gut barrier; gut function; gut permeability; indole metabolites; microbial metabolites; microbiota-gut-brain axis; tryptophan metabolism

DOI:  https://doi.org/10.1016/j.celrep.2024.114079