bims-mibica 2023-08-20 papers

bims-mibica

Biomed News

on Mitochondrial bioenergetics in cancer

Issue of 2023–08–20
33 papers selected by
Kelsey Fisher-Wellman, East Carolina University

Lactate activates the mitochondrial electron transport chain independent of its metabolism.
FASN deficiency induces a cytosol-to-mitochondria citrate flux to mitigate detachment-induced oxidative stress.
Pyruvate anaplerosis is a targetable vulnerability in persistent leukaemic stem cells.
IF1 promotes oligomeric assemblies of sluggish ATP synthase and outlines the heterogeneity of the mitochondrial membrane potential.
Hyperpolarized [1-13C]Acetyl-l-Carnitine Probes Tricarboxylic Acid Cycle Activity In Vivo.
First-in-Class NADH/Ubiquinone Oxidoreductase Core Subunit S7 (NDUFS7) Antagonist for the Treatment of Pancreatic Cancer.
Ability of metformin to deplete NAD+ contributes to cancer cell susceptibility to metformin cytotoxicity and is dependent on NAMPT expression.
Dynamics of SLC25A51 reveal preference for oxidized NAD+ and substrate led transport.
The mitochondrial succinate dehydrogenase complex controls the STAT3-IL-10 pathway in inflammatory macrophages.
Mitochondrial DNA comes with nuclear strings attached.
NME3 binds to phosphatidic acid and mediates PLD6-induced mitochondrial tethering.
One-carbon metabolizing enzyme ALDH1L1 influences mitochondrial metabolism through 5-aminoimidazole-4-carboxamide ribonucleotide accumulation and serine depletion, contributing to tumor suppression.
Sublethal engagement of apoptotic pathways in residual cancer.
Smart design of a therapeutic nanoplatform for mitochondria-targeted copper-depletion therapy combined with chemotherapy.
Discovery of Potent Allosteric DRP1 Inhibitors by Disrupting Protein-Protein Interaction with MiD49.
Nuclear genetic control of mtDNA copy number and heteroplasmy in humans.
Imaging findings of succinate dehydrogenase-deficient renal cell carcinoma.
Characterizing cancer metabolism from bulk and single-cell RNA-seq data using METAFlux.
Profiling single cancer cell metabolism via high-content SRS imaging with chemical sparsity.
Venetoclax Synergizes Sunitinib in Renal Cell Carcincoma through Inhibition of Bcl-2.
Metabolic profiling stratifies colorectal cancer and reveals adenosylhomocysteinase as a therapeutic target.
Iron promotes glycolysis to drive colon tumorigenesis.
Monitoring Mitochondria Function in Ferroptosis.
E4 ubiquitin ligase promotes mitofusin turnover and mitochondrial stress response.
Absence of mitochondrial SLC25A51 enhances PARP1-dependent DNA repair by increasing nuclear NAD+ levels.
Mitochondria-related signaling pathways involved in breast cancer regulate ferroptosis.
Pan-cancer proteogenomics connects oncogenic drivers to functional states.
Potential immunosuppressive clonal hematopoietic mutations in tumor infiltrating immune cells in breast invasive carcinoma.
PPM1D modulates hematopoietic cell fitness and response to DNA damage and is a therapeutic target in myeloid malignancy.
Anti-CD117 CAR T cells incorporating a safety switch eradicate human acute myeloid leukemia and hematopoietic stem cells.
Tolerable treatment of glioblastoma with redox-cycling 'mitocans': a comparative study in vivo.
Flavinated SDHA Underlies the Change in Intrinsic Optical Properties of Oral Cancers.
p21-activated kinase 4 suppresses fatty acid β-oxidation and ketogenesis by phosphorylating NCoR1.

bioRxiv. 2023 Aug 04. pii: 2023.08.02.551712. [Epub ahead of print]

Lactate activates the mitochondrial electron transport chain independent of its metabolism.

Xin Cai, Charles C Ng, Olivia Jones, Tak Shun Fung, Keunwoo Ryu, Dayi Li, Craig B Thompson.

Lactate has long been considered a cellular waste product. However, we found that as extracellular lactate accumulates, it also enters the mitochondrial matrix and stimulates mitochondrial electron transport chain (ETC) activity. The resulting increase in mitochondrial ATP synthesis suppresses glycolysis and increases the utilization of pyruvate and/or alternative respiratory substrates. The ability of lactate to increase oxidative phosphorylation does not depend on its metabolism. Both L- and D-lactate are effective at enhancing ETC activity and suppressing glycolysis. Furthermore, the selective induction of mitochondrial oxidative phosphorylation by unmetabolized D-lactate reversibly suppressed aerobic glycolysis in both cancer cell lines and proliferating primary cells in an ATP-dependent manner and enabled cell growth on respiratory-dependent bioenergetic substrates. In primary T cells, D-lactate enhanced cell proliferation and effector function. Together, these findings demonstrate that lactate is a critical regulator of the ability of mitochondrial oxidative phosphorylation to suppress glucose fermentation.

DOI: https://doi.org/10.1101/2023.08.02.551712
Cell Rep. 2023 Aug 12. pii: S2211-1247(23)00982-8. [Epub ahead of print]42(8): 112971

FASN deficiency induces a cytosol-to-mitochondria citrate flux to mitigate detachment-induced oxidative stress.

Wenting Dai, Zhichao Wang, Guan Wang, Qiong A Wang, Ralph DeBerardinis, Lei Jiang.

  Fatty acid synthase (FASN) maintains de novo lipogenesis (DNL) to support rapid growth in most proliferating cancer cells. Lipogenic acetyl-coenzyme A (CoA) is primarily produced from carbohydrates but can arise from glutamine-dependent reductive carboxylation. Here, we show that reductive carboxylation also occurs in the absence of DNL. In FASN-deficient cells, reductive carboxylation is mainly catalyzed by isocitrate dehydrogenase-1 (IDH1), but IDH1-generated cytosolic citrate is not utilized for supplying DNL. Metabolic flux analysis (MFA) shows that FASN deficiency induces a net cytosol-to-mitochondria citrate flux through mitochondrial citrate transport protein (CTP). Previously, a similar pathway has been shown to mitigate detachment-induced oxidative stress in anchorage-independent tumor spheroids. We further report that tumor spheroids show reduced FASN activity and that FASN-deficient cells acquire resistance to oxidative stress in a CTP- and IDH1-dependent manner. Collectively, these data indicate that by inducing a cytosol-to-mitochondria citrate flux, anchorage-independent malignant cells can gain redox capacity by trading off FASN-supported rapid growth.

Keywords:  CP: Metabolism; CP: Molecular biology; DNL; FASN inhibitor; IDH1 inhibitor; MFA; SLC25A1; anchorage-independent growth; cytosol-to-mitochondria citrate flux; de novo lipogenesis; metabolic flux analysis; redox; reductive carboxylation

DOI:  https://doi.org/10.1016/j.celrep.2023.112971
Nat Commun. 2023 Aug 17. 14(1): 4634

Pyruvate anaplerosis is a targetable vulnerability in persistent leukaemic stem cells.

Kevin M Rattigan, Zuzana Brabcova, Daniele Sarnello, Martha M Zarou, Kiron Roy, Ryan Kwan, Lucie de Beauchamp, Amy Dawson, Angela Ianniciello, Ahmed Khalaf, Eric R Kalkman, Mary T Scott, Karen Dunn, David Sumpton, Alison M Michie, Mhairi Copland, Saverio Tardito, Eyal Gottlieb, G Vignir Helgason.

Deregulated oxidative metabolism is a hallmark of leukaemia. While tyrosine kinase inhibitors (TKIs) such as imatinib have increased survival of chronic myeloid leukaemia (CML) patients, they fail to eradicate disease-initiating leukemic stem cells (LSCs). Whether TKI-treated CML LSCs remain metabolically deregulated is unknown. Using clinically and physiologically relevant assays, we generate multi-omics datasets that offer unique insight into metabolic adaptation and nutrient fate in patient-derived CML LSCs. We demonstrate that LSCs have increased pyruvate anaplerosis, mediated by increased mitochondrial pyruvate carrier 1/2 (MPC1/2) levels and pyruvate carboxylase (PC) activity, in comparison to normal counterparts. While imatinib reverses BCR::ABL1-mediated LSC metabolic reprogramming, stable isotope-assisted metabolomics reveals that deregulated pyruvate anaplerosis is not affected by imatinib. Encouragingly, genetic ablation of pyruvate anaplerosis sensitises CML cells to imatinib. Finally, we demonstrate that MSDC-0160, a clinical orally-available MPC1/2 inhibitor, inhibits pyruvate anaplerosis and targets imatinib-resistant CML LSCs in robust pre-clinical CML models. Collectively these results highlight pyruvate anaplerosis as a persistent and therapeutically targetable vulnerability in imatinib-treated CML patient-derived samples.

DOI: https://doi.org/10.1038/s41467-023-40222-z
Commun Biol. 2023 08 12. 6(1): 836

IF1 promotes oligomeric assemblies of sluggish ATP synthase and outlines the heterogeneity of the mitochondrial membrane potential.

Inés Romero-Carramiñana, Pau B Esparza-Moltó, Sonia Domínguez-Zorita, Cristina Nuevo-Tapioles, José M Cuezva.

The coexistence of two pools of ATP synthase in mitochondria has been largely neglected despite in vitro indications for the existence of reversible active/inactive state transitions in the F1-domain of the enzyme. Herein, using cells and mitochondria from mouse tissues, we demonstrate the existence in vivo of two pools of ATP synthase: one active, the other IF1-bound inactive. IF1 is required for oligomerization and inactivation of ATP synthase and for proper cristae formation. Immunoelectron microscopy shows the co-distribution of IF1 and ATP synthase, placing the inactive "sluggish" ATP synthase preferentially at cristae tips. The intramitochondrial distribution of IF1 correlates with cristae microdomains of high membrane potential, partially explaining its heterogeneous distribution. These findings support that IF1 is the in vivo regulator of the active/inactive state transitions of the ATP synthase and suggest that local regulation of IF1-ATP synthase interactions is essential to activate the sluggish ATP synthase.

DOI: https://doi.org/10.1038/s42003-023-05214-1
ACS Sens. 2023 Aug 14.

Hyperpolarized [1-13C]Acetyl-l-Carnitine Probes Tricarboxylic Acid Cycle Activity In Vivo.

Jun Chen, Tamara K Singh, Sarah Al Nemri, Maheen Zaidi, Kelvin L Billingsley, Jae Mo Park.

  Mitochondrial oxidative phosphorylation (OXPHOS) is sensitive to a variety of biological factors, and dysregulated OXPHOS is observed during the development of numerous pathological conditions. ATP production via OXPHOS is intrinsically dependent on the availability of acetyl-coenzyme A (CoA), which can enter the tricarboxylic acid (TCA) cycle to drive the oxidative pathway. Acetyl-l-carnitine (ALCAR) is an interchangeable endogenous source of acetyl-CoA, and therefore, ALCAR-derived probes are uniquely positioned for the assessment of OXPHOS. In this report, we develop hyperpolarized (HP) [1-13C]ALCAR as a noninvasive probe to investigate cardiac TCA cycle activity in vivo. We initially synthesized the isotopically labeled substrate and demonstrated that the 13C nucleus maintained a suitable T1 value (50.1 ± 0.8 s at 3 T) and polarization levels (21.3 ± 5.3%) to execute in vivo metabolic measurements. HP [1-13C]ALCAR was employed for cardiac analyses of OXPHOS in rats under fed and fasted conditions. [5-13C]Glutamate was successfully detected, and the metabolite was used to analyze the TCA cycle activity in both nutritional states. These assessments were compared to analogous experiments with the HP [1-13C]pyruvate. Our report represents the first study to demonstrate that HP methods using [1-13C]ALCAR enable direct analyses of mitochondrial function and TCA cycle activity, which are fundamental to cardiac cell homeostasis.

Keywords:  acetyl-CoA; acetyl-l-carnitine; carbon-13 MRS; cardiac oxidative metabolism; hyperpolarization; oxidative phosphorylation

DOI:  https://doi.org/10.1021/acssensors.3c01046
ACS Pharmacol Transl Sci. 2023 Aug 11. 6(8): 1164-1181

First-in-Class NADH/Ubiquinone Oxidoreductase Core Subunit S7 (NDUFS7) Antagonist for the Treatment of Pancreatic Cancer.

Yibin Xu, Ding Xue, Armita Kyani, Armand Bankhead, Joyeeta Roy, Mats Ljungman, Nouri Neamati.

Pancreatic cancer cells adapt to nutrient-scarce metabolic conditions by increasing their oxidative phosphorylation reserve to survive. Here, we present a first-in-class small-molecule NDUFS7 antagonist that inhibits oxidative phosphorylation (OXPHOS) for the treatment of pancreatic cancer. The lead compound, DX2-201, suppresses the proliferation of a panel of cell lines, and a metabolically stable analogue, DX3-213B, shows significant efficacy in a syngeneic model of pancreatic cancer. Exome sequencing of six out of six clones resistant to DX2-201 revealed a pV91M mutation in NDUFS7, providing direct evidence of its drug-binding site. In combination studies, DX2-201 showed synergy with multiple metabolic modulators, select OXPHOS inhibitors, and PARP inhibitors. Importantly, a combination with 2-deoxyglucose overcomes drug resistance in vivo. This study demonstrates that an efficacious treatment for pancreatic cancer can be achieved through inhibition of OXPHOS and direct binding to NDUFS7, providing a novel therapeutic strategy for this hard-to-treat cancer.

DOI: https://doi.org/10.1021/acsptsci.3c00069
Front Oncol. 2023 ;13 1225220

Ability of metformin to deplete NAD+ contributes to cancer cell susceptibility to metformin cytotoxicity and is dependent on NAMPT expression.

Yongxian Zhuang, Allison B Haugrud, Meg A Schaefer, Shanta M Messerli, W Keith Miskimins.

   Background: Nicotinamide adenine dinucleotide (NAD+) is vital for not only energy metabolism but also signaling pathways. A major source of NAD+ depletion is the activation of poly (ADP-ribose) polymerase (PARP) in response to DNA damage. We have previously demonstrated that metformin can cause both caspase-dependent cell death and PARP-dependent cell death in the MCF7 breast cancer cells but not in the MDA-MB-231 (231) breast cancer cells while in high-glucose media. We hypothesize that depletion of NAD+ in MCF7 cells via activation of PARP contributes to the cell death caused by metformin. Nicotinamide phosphoribosyltransferase (NAMPT), a key rate-limiting step in converting nicotinamide (vitamin B3) into NAD+, is essential for regenerating NAD+ for normal cellular processes. Evidence shows that overexpression of NAMPT is associated with tumorigenesis. We hypothesize that NAMPT expression may determine the extent to which cancer cells are sensitive to metformin.
Results: In this study, we found that metformin significantly decreases NAD+ levels over time, and that this could be delayed by PARP inhibitors. Pretreatment with NAD+ in MCF7 cells also prevents cell death and the enlargement of mitochondria and protects mitochondria from losing membrane potential caused by metformin. This leads to MCF7 cell resistance to metformin cytotoxicity in a manner similar to 231 cells. By studying the differences in NAD+ regulation in these two breast cancer cell lines, we demonstrate that NAMPT is expressed at higher levels in 231 cells than in MCF7 cells. When NAMPT is genetically repressed in 231 cells, they become much more sensitive to metformin-induced cell death. Conversely, overexpressing NAMPT in HEK-293 (293) cells causes the cells to be more resistant to metformin's growth inhibitory effects. The addition of a NAMPT activator also decreased the sensitivity of MCF7 cells to metformin, while the NAMPT activator, P7C3, protects against metformin-induced cytotoxicity.
Conclusions: Depletion of cellular NAD+ is a key aspect of sensitivity of cancer cells to the cytotoxic effects of metformin. NAMPT plays a key role in maintaining sufficient levels of NAD+, and cells that express elevated levels of NAMPT are resistant to killing by metformin.

Keywords:  breast cancer; metformin; nicotinamide adenine dinucleotide (NAD+); nicotinamide phosphoribosyltransferase (NAMPT); tumorigenesis

DOI:  https://doi.org/10.3389/fonc.2023.1225220
EMBO Rep. 2023 Aug 14. e56596

Dynamics of SLC25A51 reveal preference for oxidized NAD+ and substrate led transport.

Shivansh Goyal, Akhilesh Paspureddi, Mu-Jie Lu, Hsin-Ru Chan, Scott N Lyons, Crystal N Wilson, Marc Niere, Mathias Ziegler, Xiaolu A Cambronne.

  SLC25A51 is a member of the mitochondrial carrier family (MCF) but lacks key residues that contribute to the mechanism of other nucleotide MCF transporters. Thus, how SLC25A51 transports NAD+ across the inner mitochondrial membrane remains unclear. To elucidate its mechanism, we use Molecular Dynamics simulations to reconstitute SLC25A51 homology models into lipid bilayers and to generate hypotheses to test. We observe spontaneous binding of cardiolipin phospholipids to three distinct sites on the exterior of SLC25A51's central pore and find that mutation of these sites impairs cardiolipin binding and transporter activity. We also observe that stable formation of the required matrix gate is controlled by a single salt bridge. We identify binding sites in SLC25A51 for NAD+ and show that its selectivity for NAD+ is guided by an electrostatic interaction between the charged nicotinamide ring in the ligand and a negatively charged patch in the pore. In turn, interaction of NAD+ with interior residue E132 guides the ligand to dynamically engage and weaken the salt bridge gate, representing a ligand-induced initiation of transport.

Keywords:  MCART1; SLC25A51; mitochondrial carrier family; mitochondrial transport; nicotinamide adenine dinucleotide (NAD)

DOI:  https://doi.org/10.15252/embr.202256596
iScience. 2023 Aug 18. 26(8): 107473

The mitochondrial succinate dehydrogenase complex controls the STAT3-IL-10 pathway in inflammatory macrophages.

Dino Gobelli, Pablo Serrano-Lorenzo, María J Esteban-Amo, Julia Serna, M Teresa Pérez-García, Antonio Orduña, Alexis A Jourdain, Miguel Á Martín-Casanueva, Miguel Á de la Fuente, María Simarro.

  The functions of macrophages are tightly regulated by their metabolic state. However, the role of the mitochondrial electron transport chain (ETC) in macrophage functions remains understudied. Here, we provide evidence that the succinate dehydrogenase (SDH)/complex II (CII) is required for respiration and plays a role in controlling effector responses in macrophages. We find that the absence of the catalytic subunits Sdha and Sdhb in macrophages impairs their ability to effectively stabilize HIF-1α and produce the pro-inflammatory cytokine IL-1β in response to LPS stimulation. We also arrive at the novel result that both subunits are essential for the LPS-driven production of IL-10, a potent negative feedback regulator of the macrophage inflammatory response. This phenomenon is explained by the fact that the absence of Sdha and Sdhb leads to the inhibition of Stat3 tyrosine phosphorylation, caused partially by the excessive accumulation of mitochondrial reactive oxygen species (mitoROS) in the knockout cells.

Keywords:  Biological sciences; Cell biology; Immunology; Molecular biology

DOI:  https://doi.org/10.1016/j.isci.2023.107473
Nature. 2023 Aug 16.

Mitochondrial DNA comes with nuclear strings attached.

Sonia Boscenco, Ed Reznik.



Keywords:  Genetics

DOI:  https://doi.org/10.1038/d41586-023-01783-7
J Cell Biol. 2023 10 02. pii: e202301091. [Epub ahead of print]222(10):

NME3 binds to phosphatidic acid and mediates PLD6-induced mitochondrial tethering.

You-An Su, Hsin-Yi Chiu, Yu-Chen Chang, Chieh-Ju Sung, Chih-Wei Chen, Reika Tei, Xuang-Rong Huang, Shao-Chun Hsu, Shan-Shan Lin, Hsien-Chu Wang, Yu-Chun Lin, Jui-Cheng Hsu, Hermann Bauer, Yuxi Feng, Jeremy M Baskin, Zee-Fen Chang, Ya-Wen Liu.

Mitochondria are dynamic organelles regulated by fission and fusion processes. The fusion of membranes requires elaborative coordination of proteins and lipids and is particularly crucial for the function and quality control of mitochondria. Phosphatidic acid (PA) on the mitochondrial outer membrane generated by PLD6 facilitates the fusion of mitochondria. However, how PA promotes mitochondrial fusion remains unclear. Here, we show that a mitochondrial outer membrane protein, NME3, is required for PLD6-induced mitochondrial tethering or clustering. NME3 is enriched at the contact interface of two closely positioned mitochondria depending on PLD6, and NME3 binds directly to PA-exposed lipid packing defects via its N-terminal amphipathic helix. The PA binding function and hexamerization confer NME3 mitochondrial tethering activity. Importantly, nutrient starvation enhances the enrichment efficiency of NME3 at the mitochondrial contact interface, and the tethering ability of NME3 contributes to fusion efficiency. Together, our findings demonstrate NME3 as a tethering protein promoting selective fusion between PLD6-remodeled mitochondria for quality control.

DOI: https://doi.org/10.1083/jcb.202301091
Sci Rep. 2023 Aug 18. 13(1): 13486

One-carbon metabolizing enzyme ALDH1L1 influences mitochondrial metabolism through 5-aminoimidazole-4-carboxamide ribonucleotide accumulation and serine depletion, contributing to tumor suppression.

Masato Sasaki, Kazuo Yamamoto, Takeshi Ueda, Hayato Irokawa, Kouki Takeda, Ryoya Sekine, Fumie Itoh, Yutaka Tanaka, Shusuke Kuge, Nobuyuki Shibata.

Tumor cells generally require large amounts of nucleotides, and thus activate de novo purine synthesis (dnPS). In the dnPS reactions, 10-formyltetrahydorofolate (10-fTHF) supplied by one-carbon metabolism is utilized as a formyl group donor. We focused on aldehyde dehydrogenase 1 family member L1 (ALDH1L1), which metabolizes 10-fTHF to tetrahydrofolate and whose expression is often attenuated in hepatocellular carcinoma (HCC). We generated ALDH1L1-expressing HuH-7 cells to perform metabolome analysis and found that intracellular levels of serine were reduced and glycine was increased. In addition, 5-aminoimidazole-4-carboxamide ribonucleotide (ZMP), a dnPS intermediate, accumulated due to the consumption of 10-fTHF by ALDH1L1, which inhibited ZMP formylation. Importantly, ALDH1L1-expressing cells showed reduced ZMP sensitivity and higher mitochondrial activity. The suppression of mitochondrial serine catabolism by ALDH1L1 expression was speculated to be closely related to this phenotype. Gene set enrichment analysis utilizing The Cancer Genome Atlas data revealed that genes related to oxidative phosphorylation were enriched in HCC patients with high ALDH1L1 expression. Moreover, drug sensitivity data analysis demonstrated that HCC cell lines with low expression of ALDH1L1 were sensitive to ZMP and cordycepin, a structural analog of ZMP and AMP. Our study revealed that ZMP and AMP analogs might be effective in the pharmacotherapy of HCC patients with low expression of ALDH1L1.

DOI: https://doi.org/10.1038/s41598-023-38142-5
Trends Cell Biol. 2023 Aug 10. pii: S0962-8924(23)00138-1. [Epub ahead of print]

Sublethal engagement of apoptotic pathways in residual cancer.

Shane T Killarney, Stephen W G Tait, Douglas R Green, Kris C Wood.

  Cytotoxic chemo-, radio-, and targeted therapies frequently elicit apoptotic cancer cell death. Mitochondrial outer membrane permeabilization (MOMP) is a critical, regulated step in this apoptotic pathway. The residual cancer cells that survive treatment serve as the seeds of eventual relapse and are often functionally characterized by their transient tolerance of multiple therapeutic treatments. New studies suggest that, in these cells, a sublethal degree of MOMP, reflective of incomplete apoptotic commitment, is widely observed. Here, we review recent evidence that this sublethal MOMP drives the aggressive features of residual cancer cells while templating a host of unique vulnerabilities, highlighting how failed apoptosis may counterintuitively enable new therapeutic strategies to target residual disease (RD).

Keywords:  DNA damage response; drug-tolerant persisters; integrated stress response; sublethal MOMP

DOI:  https://doi.org/10.1016/j.tcb.2023.07.005
J Mater Chem B. 2023 Aug 14.

Smart design of a therapeutic nanoplatform for mitochondria-targeted copper-depletion therapy combined with chemotherapy.

Taishun Hu, Xiyu Gong, Xinli Liu, Hui Xu, Fangfang Zhou, Songwen Tan, Yongju He.

Mitochondria-targeted copper-depletion is emerging as an attractive strategy to combat cancer. However, existing copper molecular chelators are non-specific, toxic and ineffective. Here, it is reported that multifunctional nanoparticles (MSN-TPP/BNA-DPA) can not only target mitochondria to deprive copper ions to trigger copper-depletion therapy, but also serve as nanocarriers to deliver anticancer drugs for chemotherapy, which are engineered by conjugating a fluorophore 4-bromo-1,8-naphthalicanhydride (BNA), a copper-depriving moiety dimethylpyridinamine (DPA) and a mitochondrial targeting ligand triphenylphosphonium (TPP) on the surface of mesoporous silica nanoparticles (MSN). BNA and the internal charge transfer of compound BNA-DPA endow MSN-TPP/BNA-DPA with green fluorescence emission upon UV excitation, which can be used to monitor the cellular uptake of nanoparticles. When copper ions bind to DPA, green fluorescence is quenched, providing visualization feedback of copper-depletion. Therapeutically, mitochondria-targeted copper-depletion effectively causes mitochondria damage, elevated oxidative stress and reduced ATP production to induce intensive cancer cell death. Moreover, the mesoporous structure enables MSN-TPP/BNA-DPA to deliver doxorubicin to mitochondria for chemotherapy and enhances copper-depletion therapy through H2O2 production. Together, the synergistic therapeutic effect of enhanced copper-depletion therapy and doxorubicin-mediated chemotherapy achieves a remarkable cancer cell-killing effect and significant tumor growth inhibition in 4T1 tumor-bearing mice. This work provides an efficacious strategy for copper-depletion based synergistic cancer therapy.

DOI: https://doi.org/10.1039/d3tb00979c
ACS Med Chem Lett. 2023 Aug 10. 14(8): 1095-1099

Discovery of Potent Allosteric DRP1 Inhibitors by Disrupting Protein-Protein Interaction with MiD49.

Takeru Furuya, Jean Lin, Arina Afanaseva, Lisa Molz, Bharat Lagu, Bin Ma.

Mitochondrial dysfunction has been attributed to many disease indications, including metabolic, cardiovascular, neoplastic, and neurodegenerative diseases. Dynamin related protein 1 (DRP1) is crucial in regulating mitochondrial fission and maintaining mitochondrial homeostasis. MiD49 is a dynamic peripheral protein receptor on the surface of the mitochondrial membrane that recruits DRP1 protein to induce mitochondrial binary fission. By targeting the protein-protein interaction of DRP1/MiD49, we have discovered a novel and potent allosteric DRP1 inhibitor that inhibits mitochondria fragmentation in vitro. X-ray cocrystal structure revealed that it locked the closed DRP1 conformation by induced dimerization.

DOI: https://doi.org/10.1021/acsmedchemlett.3c00223
Nature. 2023 Aug 16.

Nuclear genetic control of mtDNA copy number and heteroplasmy in humans.

Rahul Gupta, Masahiro Kanai, Timothy J Durham, Kristin Tsuo, Jason G McCoy, Anna V Kotrys, Wei Zhou, Patrick F Chinnery, Konrad J Karczewski, Sarah E Calvo, Benjamin M Neale, Vamsi K Mootha.

Mitochondrial DNA (mtDNA) is a maternally inherited, high-copy-number genome required for oxidative phosphorylation1. Heteroplasmy refers to the presence of a mixture of mtDNA alleles in an individual and has been associated with disease and ageing. Mechanisms underlying common variation in human heteroplasmy, and the influence of the nuclear genome on this variation, remain insufficiently explored. Here we quantify mtDNA copy number (mtCN) and heteroplasmy using blood-derived whole-genome sequences from 274,832 individuals and perform genome-wide association studies to identify associated nuclear loci. Following blood cell composition correction, we find that mtCN declines linearly with age and is associated with variants at 92 nuclear loci. We observe that nearly everyone harbours heteroplasmic mtDNA variants obeying two principles: (1) heteroplasmic single nucleotide variants tend to arise somatically and accumulate sharply after the age of 70 years, whereas (2) heteroplasmic indels are maternally inherited as mixtures with relative levels associated with 42 nuclear loci involved in mtDNA replication, maintenance and novel pathways. These loci may act by conferring a replicative advantage to certain mtDNA alleles. As an illustrative example, we identify a length variant carried by more than 50% of humans at position chrM:302 within a G-quadruplex previously proposed to mediate mtDNA transcription/replication switching2,3. We find that this variant exerts cis-acting genetic control over mtDNA abundance and is itself associated in-trans with nuclear loci encoding machinery for this regulatory switch. Our study suggests that common variation in the nuclear genome can shape variation in mtCN and heteroplasmy dynamics across the human population.

DOI: https://doi.org/10.1038/s41586-023-06426-5
Clin Case Rep. 2023 Aug;11(8): e7799

Imaging findings of succinate dehydrogenase-deficient renal cell carcinoma.

Wenqin Liu, Guiwu Chen, Jiaxin Meng, Xiaomin Liao, Yuhuan Xie.

   Key Clinical Message: A 50-year-old man with a mass located in the left kidney was described by multimodal images, including ultrasonography, computed tomography, and magnetic resonance imaging. After surgical resection of the mass, pathological examination confirmed succinate dehydrogenase-deficient renal cell carcinoma.
Abstract: Succinate dehydrogenase-deficient renal cell carcinoma (SDH-deficient RCC) is a malignant tumor in the kidney associated with the loss of mitochondrial enzyme II. Due to its rarity, SDH-deficient RCC is frequently misdiagnosed. We present multimodal imaging and pathologic findings in a 50-year-old male with SDH-deficient RCC.

Keywords:  computed tomography; magnetic resonance imaging; pathology; renal cell carcinoma; succinate dehydrogenase; ultrasonography

DOI:  https://doi.org/10.1002/ccr3.7799
Nat Commun. 2023 Aug 12. 14(1): 4883

Characterizing cancer metabolism from bulk and single-cell RNA-seq data using METAFlux.

Yuefan Huang, Vakul Mohanty, Merve Dede, Kyle Tsai, May Daher, Li Li, Katayoun Rezvani, Ken Chen.

Cells often alter metabolic strategies under nutrient-deprived conditions to support their survival and growth. Characterizing metabolic reprogramming in the tumor microenvironment (TME) is of emerging importance in cancer research and patient care. However, recent technologies only measure a subset of metabolites and cannot provide in situ measurements. Computational methods such as flux balance analysis (FBA) have been developed to estimate metabolic flux from bulk RNA-seq data and can potentially be extended to single-cell RNA-seq (scRNA-seq) data. However, it is unclear how reliable current methods are, particularly in TME characterization. Here, we present a computational framework METAFlux (METAbolic Flux balance analysis) to infer metabolic fluxes from bulk or single-cell transcriptomic data. Large-scale experiments using cell-lines, the cancer genome atlas (TCGA), and scRNA-seq data obtained from diverse cancer and immunotherapeutic contexts, including CAR-NK cell therapy, have validated METAFlux's capability to characterize metabolic heterogeneity and metabolic interaction amongst cell types.

DOI: https://doi.org/10.1038/s41467-023-40457-w
Sci Adv. 2023 Aug 18. 9(33): eadg6061

Profiling single cancer cell metabolism via high-content SRS imaging with chemical sparsity.

Yuying Tan, Haonan Lin, Ji-Xin Cheng.

Metabolic reprogramming in a subpopulation of cancer cells is a hallmark of tumor chemoresistance. However, single-cell metabolic profiling is difficult because of the lack of a method that can simultaneously detect multiple metabolites at the single-cell level. In this study, through hyperspectral stimulated Raman scattering (hSRS) imaging in the carbon-hydrogen (C-H) window and sparsity-driven hyperspectral image decomposition, we demonstrate a high-content hSRS (h2SRS) imaging approach that enables the simultaneous mapping of five major biomolecules, including proteins, carbohydrates, fatty acids, cholesterol, and nucleic acids at the single-cell level. h2SRS imaging of brain and pancreatic cancer cells under chemotherapy revealed acute and adapted chemotherapy-induced metabolic reprogramming and the unique metabolic features of chemoresistance. Our approach is expected to facilitate the discovery of therapeutic targets to combat chemoresistance. This study illustrates a high-content, label-free chemical imaging approach that measures metabolic profiles at the single-cell level and warrants further research on cellular metabolism.

DOI: https://doi.org/10.1126/sciadv.adg6061
Anticancer Agents Med Chem. 2023 Aug 15.

Venetoclax Synergizes Sunitinib in Renal Cell Carcincoma through Inhibition of Bcl-2.

Yuanjia Tang, Tao Song, Liangkui Gao, Fei Mao.

   AIMS: More effective treatment options for patients with renal cell carcinoma (RCC) are needed, in particular advanced RCC.
BACKGROUND: Sunitinib, a multitarget tyrosine kinase inhibitor, is a first-line treatment of metastatic RCC. However, the management of sunitinib-induced adverse events and resistance is complex. In hematological malignancies, effective targeting of anti-apoptotic proteins such as Bcl-2 has been achieved, but limited progress has been made in solid tumors.
OBJECTIVE: This work systematically investigated the therapeutic potential of the combination of sunitinib and venetoclax, a Bcl-2 inhibitor, in preclinical RCC models.
METHOD: Quantitative analysis of drug interactions was performed. Cell viability was examined after drug treatment or Bcl-2 siRNA depletion. RCC xenograft mouse model was applied to validate the efficacy of sunitinib and venetoclax.
RESULT: A strong synergistic interaction between sunitinib and venetoclax was observed across a range of different dose levels in all tested RCC cell lines. Sequential treatment studies show that the sequential addition of venetoclax and then sunitinib is superior to concurrent treatment and the sequential addition of sunitinib and then venetoclax in decreasing RCC cell viability. The sensitivity of RCC cell lines to venetoclax treatment negatively correlates with their Bcl-2 levels. Specific depletion of Bcl-2 mimics the synergistic effects of venetoclax with sunitinib. Treatment of mice implanted with high Bcl-2-expressing RCC cells reveals that a combination of venetoclax and sunitinib at a non-toxic dose displays complete regression of tumor growth throughout the whole duration of treatment.
CONCLUSION: Our work demonstrates that inhibiting Bcl-2 by venetoclax synergistically enhances sunitinib's efficacy in RCC. Venetoclax holds great potential as a viable option for clinical use.

Keywords:  Bcl-2; advanced RCC; renal cell carcinoma; sunitinib; synergism; venetoclax

DOI:  https://doi.org/10.2174/1871520623666230815143303
Nat Metab. 2023 Aug 14.

Metabolic profiling stratifies colorectal cancer and reveals adenosylhomocysteinase as a therapeutic target.

Johan Vande Voorde, Rory T Steven, Arafath K Najumudeen, Catriona A Ford, Alex Dexter, Ariadna Gonzalez-Fernandez, Chelsea J Nikula, Yuchen Xiang, Lauren Ford, Stefania Maneta Stavrakaki, Kathryn Gilroy, Lucas B Zeiger, Kathryn Pennel, Phimmada Hatthakarnkul, Efstathios A Elia, Ammar Nasif, Teresa Murta, Eftychios Manoli, Sam Mason, Michael Gillespie, Tamsin R M Lannagan, Nikola Vlahov, Rachel A Ridgway, Colin Nixon, Alexander Raven, Megan Mills, Dimitris Athineos, Georgios Kanellos, Craig Nourse, David M Gay, Mark Hughes, Amy Burton, Bin Yan, Katherine Sellers, Vincen Wu, Kobe De Ridder, Engy Shokry, Alejandro Huerta Uribe, William Clark, Graeme Clark, Kristina Kirschner, Bernard Thienpont, Vivian S W Li, Oliver D K Maddocks, Simon T Barry, Richard J A Goodwin, James Kinross, Joanne Edwards, Mariia O Yuneva, David Sumpton, Zoltan Takats, Andrew D Campbell, Josephine Bunch, Owen J Sansom.

The genomic landscape of colorectal cancer (CRC) is shaped by inactivating mutations in tumour suppressors such as APC, and oncogenic mutations such as mutant KRAS. Here we used genetically engineered mouse models, and multimodal mass spectrometry-based metabolomics to study the impact of common genetic drivers of CRC on the metabolic landscape of the intestine. We show that untargeted metabolic profiling can be applied to stratify intestinal tissues according to underlying genetic alterations, and use mass spectrometry imaging to identify tumour, stromal and normal adjacent tissues. By identifying ions that drive variation between normal and transformed tissues, we found dysregulation of the methionine cycle to be a hallmark of APC-deficient CRC. Loss of Apc in the mouse intestine was found to be sufficient to drive expression of one of its enzymes, adenosylhomocysteinase (AHCY), which was also found to be transcriptionally upregulated in human CRC. Targeting of AHCY function impaired growth of APC-deficient organoids in vitro, and prevented the characteristic hyperproliferative/crypt progenitor phenotype driven by acute deletion of Apc in vivo, even in the context of mutant Kras. Finally, pharmacological inhibition of AHCY reduced intestinal tumour burden in ApcMin/+ mice indicating its potential as a metabolic drug target in CRC.

DOI: https://doi.org/10.1038/s42255-023-00857-0
Biochim Biophys Acta Mol Basis Dis. 2023 Aug 12. pii: S0925-4439(23)00212-0. [Epub ahead of print] 166846

Iron promotes glycolysis to drive colon tumorigenesis.

Zhaoli Liu, Luke Villareal, Lavanya Goodla, Hyeoncheol Kim, Daniel M Falcon, Mohammad Haneef, David R Martin, Li Zhang, Ho-Joon Lee, Daniel Kremer, Costas A Lyssiotis, Yatrik M Shah, Henry C Lin, Hui-Kuan Lin, Xiang Xue.

  Colorectal cancer (CRC) is the third most common cancer and is also the third leading cause of cancer-related death in the USA. Understanding the mechanisms of growth and progression of CRC is essential to improve treatment. Macronutrients such as glucose are energy source for a cell. Many tumor cells exhibit increased aerobic glycolysis. Increased tissue micronutrient iron levels in both mice and humans are also associated with increased colon tumorigenesis. However, if iron drives colon carcinogenesis via affecting glucose metabolism is still not clear. Here we found the intracellular glucose levels in tumor colonoids were significantly increased after iron treatment. 13C-labeled glucose flux analysis indicated that the levels of several labeled glycolytic products were significantly increased, whereas several tricarboxylic acid cycle intermediates were significantly decreased in colonoids after iron treatment. Mechanistic studies showed that iron upregulated the expression of glucose transporter 1 (GLUT1) and mediated an inhibition of the pyruvate dehydrogenase (PDH) complex function via directly binding with tankyrase and/or pyruvate dehydrogenase kinase (PDHK) 3. Pharmacological inhibition of GLUT1 or PDHK reactivated PDH complex function and reduced high iron diet-enhanced tumor formation. In conclusion, excess iron promotes glycolysis and colon tumor growth at least partly through the inhibition of the PDH complex function.

Keywords:  GLUT1; Glucose; Iron; PDH; PDHK3; Tankyrase

DOI:  https://doi.org/10.1016/j.bbadis.2023.166846
Methods Mol Biol. 2023 ;2712 103-115

Monitoring Mitochondria Function in Ferroptosis.

Fangquan Chen, Jiao Liu, Daolin Tang, Rui Kang.

  Ferroptosis is a type of regulated necrosis driven by uncontrolled membrane lipid peroxidation. Mitochondria, which are membrane-bound organelles present in almost all eukaryotic cells and play a central role in energy metabolism and various types of cell death, have a complicated role in ferroptosis. On one hand, mitochondrial-derived iron metabolism and reactive oxygen species (ROS) production may promote ferroptosis. On the other hand, mitochondria also possess a dihydroorotate dehydrogenase (DHODH)-dependent antioxidant system that detoxifies lipid peroxides. This chapter summarizes several methods, such as western blotting, immunofluorescence, cell viability assays, mitochondrial fluorescent probes, adenosine 5'-triphosphate (ATP) assay kits, mitochondrial respiration, and mitophagy tests, that may enable researchers to gain a deeper understanding of the dual role of mitochondria in ferroptosis.

Keywords:  Ferroptosis; Methods; Mitochondria

DOI:  https://doi.org/10.1007/978-1-0716-3433-2_10
Mol Cell. 2023 Aug 17. pii: S1097-2765(23)00563-4. [Epub ahead of print]83(16): 2976-2990.e9

E4 ubiquitin ligase promotes mitofusin turnover and mitochondrial stress response.

Vincent Anton, Ira Buntenbroich, Tânia Simões, Mariana Joaquim, Leonie Müller, Reinhard Buettner, Margarete Odenthal, Thorsten Hoppe, Mafalda Escobar-Henriques.

  Ubiquitin-dependent control of mitochondrial dynamics is important for protein quality and neuronal integrity. Mitofusins, mitochondrial fusion factors, can integrate cellular stress through their ubiquitylation, which is carried out by multiple E3 enzymes in response to many different stimuli. However, the molecular mechanisms that enable coordinated responses are largely unknown. Here we show that yeast Ufd2, a conserved ubiquitin chain-elongating E4 enzyme, is required for mitochondrial shape adjustments. Under various stresses, Ufd2 translocates to mitochondria and triggers mitofusin ubiquitylation. This elongates ubiquitin chains on mitofusin and promotes its proteasomal degradation, leading to mitochondrial fragmentation. Ufd2 and its human homologue UBE4B also target mitofusin mutants associated with Charcot-Marie-Tooth disease, a hereditary sensory and motor neuropathy characterized by progressive loss of the peripheral nerves. This underscores the pathophysiological importance of E4-mediated ubiquitylation in neurodegeneration. In summary, we identify E4-dependent mitochondrial stress adaptation by linking various metabolic processes to mitochondrial fusion and fission dynamics.

Keywords:  CMT2A; Cdc48/p97; E4; Fzo1; MFN2; UBE4B; Ufd2; fusion; mitochondria; mitofusin; stress; ubiquitin

DOI:  https://doi.org/10.1016/j.molcel.2023.07.021
Nucleic Acids Res. 2023 Aug 17. pii: gkad659. [Epub ahead of print]

Absence of mitochondrial SLC25A51 enhances PARP1-dependent DNA repair by increasing nuclear NAD+ levels.

Anka Güldenpfennig, Ann-Katrin Hopp, Lukas Muskalla, Patrick Manetsch, Fabio Raith, Lars Hellweg, Cyril Dördelmann, Deena M Leslie Pedrioli, Kai Johnsson, Giulio Superti-Furga, Michael O Hottiger.

Though the effect of the recently identified mitochondrial NAD+ transporter SLC25A51 on glucose metabolism has been described, its contribution to other NAD+-dependent processes throughout the cell such as ADP-ribosylation remains elusive. Here, we report that absence of SLC25A51 leads to increased NAD+ concentration not only in the cytoplasm and but also in the nucleus. The increase is not associated with upregulation of the salvage pathway, implying an accumulation of constitutively synthesized NAD+ in the cytoplasm and nucleus. This results in an increase of PARP1-mediated nuclear ADP-ribosylation, as well as faster repair of DNA lesions induced by different single-strand DNA damaging agents. Lastly, absence of SLC25A51 reduces both MMS/Olaparib induced PARP1 chromatin retention and the sensitivity of different breast cancer cells to PARP1 inhibition. Together these results provide evidence that SLC25A51 might be a novel target to improve PARP1 inhibitor based therapies by changing subcellular NAD+ redistribution.

DOI: https://doi.org/10.1093/nar/gkad659
Genes Dis. 2024 Jan;11(1): 358-366

Mitochondria-related signaling pathways involved in breast cancer regulate ferroptosis.

Xinrui Dong, Ye Li, Xiaonan Sheng, Weihang Zhou, Aijun Sun, Huijuan Dai.

  Ferroptosis is a novel form of regulated cell death characterized by iron-dependent excessive lipid peroxidation. The core organelle involved in ferroptosis is mitochondria. Mitochondria undergoing ferroptosis are distinct from normal mitochondria in terms of morphology, biochemistry, gene expression, and energy metabolism. An increasing number of studies have shown that mitochondria and their associated metabolic pathways mediate ferroptosis in the development and progression of breast cancer. In this review, we discuss the relevant research about ferroptosis in breast cancer and provide a comprehensive summary of mitochondrial regulation in ferroptosis from the perspective of lipid metabolism, oxidative phosphorylation, ion metabolism, glycometabolism, and nucleotide metabolism. We also summarize the application of mitochondrial metabolism-related pathways as ferroptosis treatment targets. Here we provide new insights into the relationship between mitochondria, ferroptosis, and breast cancer treatment.

Keywords:  Breast cancer; Cancer treatment; Ferroptosis; Lipid metabolism; Mitochondria; Oxidative phosphorylation

DOI:  https://doi.org/10.1016/j.gendis.2023.03.019
Cell. 2023 Aug 14. pii: S0092-8674(23)00780-8. [Epub ahead of print]

Pan-cancer proteogenomics connects oncogenic drivers to functional states.

Clinical Proteomic Tumor Analysis Consortium

  Cancer driver events refer to key genetic aberrations that drive oncogenesis; however, their exact molecular mechanisms remain insufficiently understood. Here, our multi-omics pan-cancer analysis uncovers insights into the impacts of cancer drivers by identifying their significant cis-effects and distal trans-effects quantified at the RNA, protein, and phosphoprotein levels. Salient observations include the association of point mutations and copy-number alterations with the rewiring of protein interaction networks, and notably, most cancer genes converge toward similar molecular states denoted by sequence-based kinase activity profiles. A correlation between predicted neoantigen burden and measured T cell infiltration suggests potential vulnerabilities for immunotherapies. Patterns of cancer hallmarks vary by polygenic protein abundance ranging from uniform to heterogeneous. Overall, our work demonstrates the value of comprehensive proteogenomics in understanding the functional states of oncogenic drivers and their links to cancer development, surpassing the limitations of studying individual cancer types.

Keywords:  CPTAC; cancer hallmark; oncogenic driver; pan-cancer; phosphoproteomics; protein complex; proteogenomics; proteomics; therapeutic target

DOI:  https://doi.org/10.1016/j.cell.2023.07.014
Sci Rep. 2023 08 12. 13(1): 13131

Potential immunosuppressive clonal hematopoietic mutations in tumor infiltrating immune cells in breast invasive carcinoma.

Ramu Anandakrishnan, Ian J Zyvoloski, Lucas R Zyvoloski, Nana K Opoku, Andrew Dai, Veneeth Antony.

A hallmark of cancer is a tumor cell's ability to evade immune destruction. Somatic mutations in tumor cells that prevent immune destruction have been extensively studied. However, somatic mutations in tumor infiltrating immune (TII) cells, to our knowledge, have not been previously studied. Understandably so since normal hematopoiesis prevents the accumulation of somatic mutations in immune cells. However, clonal hematopoiesis does result in the accumulation of somatic mutations in immune cells. These mutations cannot "drive" tumor growth, however, they may "facilitate" it by inhibiting an effective anti-tumor immune response. To identify potential immunosuppressive clonal hematopoietic (CH) mutations in TII cells, we analyzed exome and RNA sequencing data from matched tumor and normal blood samples, and single-cell RNA sequencing data, from breast cancer patients. We selected mutations that were somatic, present in TII cells, clonally expanded, potentially pathogenic, expressed in TII cells, unlikely to be a passenger mutation, and in immune response associated genes. We identified eight potential immunosuppressive CH mutations in TII cells. This work is a first step towards determining if immunosuppressive CH mutations in TII cells can affect the progression of solid tumors. Subsequent experimental confirmation could represent a new paradigm in the etiology of cancer.

DOI: https://doi.org/10.1038/s41598-023-40256-9
Blood. 2023 Aug 18. pii: blood.2023020331. [Epub ahead of print]

PPM1D modulates hematopoietic cell fitness and response to DNA damage and is a therapeutic target in myeloid malignancy.

Peter Grant Miller, Adam S Sperling, Christina Mayerhofer, Marie McConkey, Jana Maria Ellegast, Carmen Da Silva, Drew Nathaniel Cohen, Chuqi Wang, Azeem Sharda, Ni Yan, Subha Saha, Cameron Schluter, Ilexa Ashley Schechter, Mikołaj Słabicki, Brittany Sandoval, Josephine Kahn, Steffen Boettcher, Christopher J Gibson, David T Scadden, Kimberly Stegmaier, Shruti Bhatt, R Coleman Lindsley, Benjamin L Ebert.

PPM1D encodes a phosphatase that is recurrently activated across cancer, most notably in therapy-related myeloid neoplasms. However, the function of PPM1D in hematopoiesis and its contribution to tumor cell growth remain incompletely understood. Using conditional mouse models, we uncover a central role for Ppm1d in hematopoiesis and validate its potential as a therapeutic target. We find that Ppm1d regulates the competitive fitness and self-renewal of hematopoietic stem cells (HSCs) with and without exogenous genotoxic stresses. We also show that while Ppm1d activation confers cellular resistance to cytotoxic therapy, it does so to a lesser degree than p53 loss, informing the clonal competition phenotypes often observed in human studies. Notably, loss of Ppm1d sensitizes leukemias to cytotoxic therapies in vitro and in vivo, even in the absence of a Ppm1d mutation. Vulnerability to PPM1D inhibition is observed across many cancer types and dependent on p53 activity. Importantly, organism-wide loss of Ppm1d in adult mice is well tolerated, supporting the tolerability of pharmacologically targeting PPM1D. Our data link PPM1D gain-of-function mutations to the clonal expansion of HSCs, inform human genetic observations, and support the therapeutic targeting of PPM1D in cancer.

DOI: https://doi.org/10.1182/blood.2023020331
Mol Ther Oncolytics. 2023 Sep 21. 30 56-71

Anti-CD117 CAR T cells incorporating a safety switch eradicate human acute myeloid leukemia and hematopoietic stem cells.

Chiara F Magnani, Renier Myburgh, Silvan Brunn, Morgane Chambovey, Marianna Ponzo, Laura Volta, Francesco Manfredi, Christian Pellegrino, Steve Pascolo, Csaba Miskey, Zoltán Ivics, Judith A Shizuru, Dario Neri, Markus G Manz.

  Discrimination between hematopoietic stem cells and leukemic stem cells remains a major challenge for acute myeloid leukemia immunotherapy. CAR T cells specific for the CD117 antigen can deplete malignant and healthy hematopoietic stem cells before consolidation with allogeneic hematopoietic stem cell transplantation in absence of cytotoxic conditioning. Here we exploit non-viral technology to achieve early termination of CAR T cell activity to prevent incoming graft rejection. Transient expression of an anti-CD117 CAR by mRNA conferred T cells the ability to eliminate CD117+ targets in vitro and in vivo. As an alternative approach, we used a Sleeping Beauty transposon vector for the generation of CAR T cells incorporating an inducible Caspase 9 safety switch. Stable CAR expression was associated with high proportion of T memory stem cells, low levels of exhaustion markers, and potent cellular cytotoxicity. Anti-CD117 CAR T cells mediated depletion of leukemic cells and healthy hematopoietic stem cells in NSG mice reconstituted with human leukemia or CD34+ cord blood cells, respectively, and could be terminated in vivo. The use of a non-viral technology to control CAR T cell pharmacokinetic properties is attractive for a first-in-human study in patients with acute myeloid leukemia prior to hematopoietic stem cell transplantation.

Keywords:  CAR; Chimeric antigen receptor; acute myeloid leukemia; cancer immunotherapy; hematopoietic stem cell; non-viral gene transfer

DOI:  https://doi.org/10.1016/j.omto.2023.07.003
Redox Rep. 2023 Dec;28(1): 2220531

Tolerable treatment of glioblastoma with redox-cycling 'mitocans': a comparative study in vivo.

Akira Sumiyoshi, Sayaka Shibata, Dessislava Lazarova, Zhivko Zhelev, Ichio Aoki, Rumiana Bakalova.

  Objectives: The present study describes a pharmacological strategy for the treatment of glioblastoma by redoxcycling 'mitocans' such as quinone/ascorbate combination drugs, based on their tumor-selective redox-modulating effects and tolerance to normal cells and tissues.Methods: Experiments were performed on glioblastoma mice (orthotopic model) treated with coenzyme Q0/ascorbate (Q0/A). The drug was injected intracranially in a single dose. The following parameters were analyzed in vivo using MRI orex vivo using conventional assays: tumor growth, survival, cerebral and tumor perfusion, tumor cell density, tissue redox-state, and expression of tumor-associated NADH oxidase (tNOX).Results: Q0/A markedly suppressed tumor growth and significantly increased survival of glioblastoma mice. This was accompanied by increased oxidative stress in the tumor but not in non-cancerous tissues, increased tumor blood flow, and downregulation of tNOX. The redox-modulating and anticancer effects of Q0/A were more pronounced than those of menadione/ascorbate (M/A) obtained in our previous study. No adverse drug-related side-effects were observed in glioblastoma mice treated with Q0/A.Discussion: Q0/A differentiated cancer cells and tissues, particularly glioblastoma, from normal ones by redox targeting, causing a severe oxidative stress in the tumor but not in non-cancerous tissues. Q0/A had a pronounced anticancer activity and could be considered safe for the organism within certain concentration limits. The results suggest that the rate of tumor resorption and metabolism of toxic residues must be controlled and maintained within tolerable limits to achieve longer survival, especially at intracranial drug administration.

Keywords:  Redox-cyclers; ascorbate; cerebral perfusion; coenzyme Q0; glioblastoma; menadione; oxidative stress; tNOX; tumor cell density

DOI:  https://doi.org/10.1080/13510002.2023.2220531
bioRxiv. 2023 Jul 31. pii: 2023.07.30.551184. [Epub ahead of print]

Flavinated SDHA Underlies the Change in Intrinsic Optical Properties of Oral Cancers.

Tomoko Marumo, Chima V Maduka, Evran Ural, Ehsanul Hoque Apu, Seock-Jin Chung, Nynke S van den Berg, Quan Zhou, Brock A Martin, Eben L Rosenthal, Takahiko Shibahara, Christopher H Contag.

The molecular basis of reduced autofluorescence in oral squamous cell carcinoma (OSCC) cells relative to normal cells has been speculated to be due to lower levels of free flavin adenine dinucleotide (FAD). This speculation, along with differences in the intrinsic optical properties of extracellular collagen, lie at the foundation of the design of currently-used clinical optical detection devices. Here, we report that free FAD levels may not account for differences in autofluorescence of OSCC cells, but that the differences relate to FAD as a co-factor for flavination. Autofluorescence from a 70 kDa flavoprotein, succinate dehydrogenase A (SDHA), was found to be responsible for changes in optical properties within the FAD spectral region with lower levels of flavinated SDHA in OSCC cells. Since flavinated SDHA is required for functional complexation with succinate dehydrogenase B (SDHB), decreased SDHB levels were observed in human OSCC tissue relative to normal tissues. Accordingly, the metabolism of OSCC cells was found to be significantly altered relative to normal cells, revealing vulnerabilities for both diagnosis and targeted therapy. Optimizing non-invasive tools based on optical and metabolic signatures of cancers will enable more precise and early diagnosis leading to improved outcomes in patients.

DOI: https://doi.org/10.1101/2023.07.30.551184
Nat Commun. 2023 Aug 17. 14(1): 4987

p21-activated kinase 4 suppresses fatty acid β-oxidation and ketogenesis by phosphorylating NCoR1.

Min Yan Shi, Hwang Chan Yu, Chang Yeob Han, In Hyuk Bang, Ho Sung Park, Kyu Yun Jang, Sangkyu Lee, Jeong Bum Son, Nam Doo Kim, Byung-Hyun Park, Eun Ju Bae.

PPARα corepressor NCoR1 is a key regulator of fatty acid β-oxidation and ketogenesis. However, its regulatory mechanism is largely unknown. Here, we report that oncoprotein p21-activated kinase 4 (PAK4) is an NCoR1 kinase. Specifically, PAK4 phosphorylates NCoR1 at T1619/T2124, resulting in an increase in its nuclear localization and interaction with PPARα, thereby repressing the transcriptional activity of PPARα. We observe impaired ketogenesis and increases in PAK4 protein and NCoR1 phosphorylation levels in liver tissues of high fat diet-fed mice, NAFLD patients, and hepatocellular carcinoma patients. Forced overexpression of PAK4 in mice represses ketogenesis and thereby increases hepatic fat accumulation, whereas genetic ablation or pharmacological inhibition of PAK4 exhibites an opposite phenotype. Interestingly, PAK4 protein levels are significantly suppressed by fasting, largely through either cAMP/PKA- or Sirt1-mediated ubiquitination and proteasome degradation. In this way, our findings provide evidence for a PAK4-NCoR1/PPARα signaling pathway that regulates fatty acid β-oxidation and ketogenesis.

DOI: https://doi.org/10.1038/s41467-023-40597-z