bims-mibica Biomed News
on Mitochondrial bioenergetics in cancer
Issue of 2024–07–21
eleven papers selected by
Kelsey Fisher-Wellman, East Carolina University
  1. Amino acids trigger MDC-dependent mitochondrial remodeling by altering mitochondrial function.
  2. Metabolic Reprogramming Is an Initial Step in Pancreatic Carcinogenesis That Can Be Targeted to Inhibit Acinar-to-Ductal Metaplasia.
  3. ATAD1 prevents clogging of TOM and damage caused by un-imported mitochondrial proteins.
  4. Robustness of mitochondrial biogenesis and respiration explain aerobic glycolysis.
  5. Mitochondrial Proteins as Metabolic Biomarkers and Sites for Therapeutic Intervention in Primary and Metastatic Cancers.
  6. Targeting valine catabolism to inhibit metabolic reprogramming in prostate cancer.
  7. Targeting the Sodium-Potassium Pump as a Therapeutic Strategy in Acute Myeloid Leukemia.
  8. Metabolic imaging across scales reveals distinct prostate cancer phenotypes.
  9. Supernumerary proteins of the human mitochondrial ribosomal small subunit are integral for assembly and translation.
  10. Tumor suppressor KEAP1 promotes HSPA9 degradation, controlling mitochondrial biogenesis in breast cancer.
  11. Real-world effectiveness of first-line azacitidine or decitabine with or without venetoclax in acute myeloid leukemia patients unfit for intensive therapy.
  1. bioRxiv. 2024 Jul 12. pii: 2024.07.09.602707. [Epub ahead of print]
    Amino acids trigger MDC-dependent mitochondrial remodeling by altering mitochondrial function.
    Nidhi Raghuram, Adam Hughes.
      Cells utilize numerous pathways to maintain mitochondrial homeostasis, including a recently identified mechanism that adjusts the content of the outer mitochondrial membrane (OMM) through formation of OMM-derived multilamellar domains called mitochondrial-derived compartments, or MDCs. MDCs are triggered by perturbations in mitochondrial lipid and protein content, as well as increases in intracellular amino acids. Here, we sought to understand how amino acids trigger MDCs. We show that amino acid-activation of MDCs is dependent on the functional state of mitochondria. While amino acid excess triggers MDC formation when cells are grown on fermentable carbon sources, stimulating mitochondrial biogenesis blocks MDC formation. Moreover, amino acid elevation depletes TCA cycle metabolites in yeast, and preventing consumption of TCA cycle intermediates for amino acid catabolism suppresses MDC formation. Finally, we show that directly impairing the TCA cycle is sufficient to trigger MDC formation in the absence of amino acid stress. These results demonstrate that amino acids stimulate MDC formation by perturbing mitochondrial metabolism.
    DOI:  https://doi.org/10.1101/2024.07.09.602707
  2. Cancer Res. 2024 Jul 15. 84(14): 2297-2312
    Metabolic Reprogramming Is an Initial Step in Pancreatic Carcinogenesis That Can Be Targeted to Inhibit Acinar-to-Ductal Metaplasia.
    Thorsten Neuß, Min-Chun Chen, Nils Wirges, Sinem Usluer, Rupert Oellinger, Svenja Lier, Michael Dudek, Tobias Madl, Martin Jastroch, Katja Steiger, Werner Schmitz, Henrik Einwächter, Roland M Schmid.
      Metabolic reprogramming is a hallmark of cancer and is crucial for cancer progression, making it an attractive therapeutic target. Understanding the role of metabolic reprogramming in cancer initiation could help identify prevention strategies. To address this, we investigated metabolism during acinar-to-ductal metaplasia (ADM), the first step of pancreatic carcinogenesis. Glycolytic markers were elevated in ADM lesions compared with normal tissue from human samples. Comprehensive metabolic assessment in three mouse models with pancreas-specific activation of KRAS, PI3K, or MEK1 using Seahorse measurements, nuclear magnetic resonance metabolome analysis, mass spectrometry, isotope tracing, and RNA sequencing analysis revealed a switch from oxidative phosphorylation to glycolysis in ADM. Blocking the metabolic switch attenuated ADM formation. Furthermore, mitochondrial metabolism was required for de novo synthesis of serine and glutathione (GSH) but not for ATP production. MYC mediated the increase in GSH intermediates in ADM, and inhibition of GSH synthesis suppressed ADM development. This study thus identifies metabolic changes and vulnerabilities in the early stages of pancreatic carcinogenesis. Significance: Metabolic reprogramming from oxidative phosphorylation to glycolysis mediated by MYC plays a crucial role in the development of pancreatic cancer, revealing a mechanism driving tumorigenesis and potential therapeutic targets. See related commentary by Storz, p. 2225.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-23-2213
  3. Cell Rep. 2024 Jul 17. pii: S2211-1247(24)00802-7. [Epub ahead of print]43(8): 114473
    ATAD1 prevents clogging of TOM and damage caused by un-imported mitochondrial proteins.
    John Kim, Madeleine Goldstein, Lauren Zecchel, Ryan Ghorayeb, Christopher A Maxwell, Hilla Weidberg.
      Mitochondria require the constant import of nuclear-encoded proteins for proper functioning. Impaired protein import not only depletes mitochondria of essential factors but also leads to toxic accumulation of un-imported proteins outside the organelle. Here, we investigate the consequences of impaired mitochondrial protein import in human cells. We demonstrate that un-imported proteins can clog the mitochondrial translocase of the outer membrane (TOM). ATAD1, a mitochondrial ATPase, removes clogged proteins from TOM to clear the entry gate into the mitochondria. ATAD1 interacts with both TOM and stalled proteins, and its knockout results in extensive accumulation of mitochondrial precursors as well as decreased protein import. Increased ATAD1 expression contributes to improved fitness of cells with inefficient mitochondrial protein import. Overall, we demonstrate the importance of the ATAD1 quality control pathway in surveilling protein import and its contribution to cellular health.
    Keywords:  AAA ATPase; ATAD1; CP: Cell biology; CP: Metabolism; TOM clogging; mitochondrial protein import; mitochondrial stress; protein quality control; proteotoxicity
    DOI:  https://doi.org/10.1016/j.celrep.2024.114473
  4. bioRxiv. 2024 Jul 05. pii: 2024.07.04.601975. [Epub ahead of print]
    Robustness of mitochondrial biogenesis and respiration explain aerobic glycolysis.
    Easun Arunachalam, Felix C Keber, Richard C Law, Chirag K Kumar, Yihui Shen, Junyoung O Park, Martin Wühr, Daniel J Needleman.
      A long-standing observation is that in fast-growing cells, respiration rate declines with increasing growth rate and is compensated by an increase in fermentation, despite respiration being more efficient than fermentation. This apparent preference for fermentation even in the presence of oxygen is known as aerobic glycolysis, and occurs in bacteria, yeast, and cancer cells. Considerable work has focused on understanding the potential benefits that might justify this seemingly wasteful metabolic strategy, but its mechanistic basis remains unclear. Here we show that aerobic glycolysis results from the saturation of mitochondrial respiration and the decoupling of mitochondrial biogenesis from the production of other cellular components. Respiration rate is insensitive to acute perturbations of cellular energetic demands or nutrient supplies, and is explained simply by the amount of mitochondria per cell. Mitochondria accumulate at a nearly constant rate across different growth conditions, resulting in mitochondrial amount being largely determined by cell division time. In contrast, glucose uptake rate is not saturated, and is accurately predicted by the abundances and affinities of glucose transporters. Combining these models of glucose uptake and respiration provides a quantitative, mechanistic explanation for aerobic glycolysis. The robustness of specific respiration rate and mitochondrial biogenesis, paired with the flexibility of other bioenergetic and biosynthetic fluxes, may play a broad role in shaping eukaryotic cell metabolism.
    DOI:  https://doi.org/10.1101/2024.07.04.601975
  5. Mini Rev Med Chem. 2024 ;24(12): 1187-1202
    Mitochondrial Proteins as Metabolic Biomarkers and Sites for Therapeutic Intervention in Primary and Metastatic Cancers.
    Diana Xochiquetzal Robledo-Cadena, Silvia Cecilia Pacheco-Velazquez, Jorge Luis Vargas-Navarro, Joaquín Alberto Padilla-Flores, Rafael Moreno-Sanchez, Sara Rodríguez-Enríquez.
      Accelerated aerobic glycolysis is one of the main metabolic alterations in cancer, associated with malignancy and tumor growth. Although glycolysis is one of the most studied properties of tumor cells, recent studies demonstrate that oxidative phosphorylation (OxPhos) is the main ATP provider for the growth and development of cancer. In this last regard, the levels of mRNA and protein of OxPhos enzymes and transporters (including glutaminolysis, acetate and ketone bodies catabolism, free fatty acid β-oxidation, Krebs Cycle, respiratory chain, phosphorylating system- ATP synthase, ATP/ADP translocator, Pi carrier) are altered in tumors and cancer cells in comparison to healthy tissues and organs, and non-cancer cells. Both energy metabolism pathways are tightly regulated by transcriptional factors, oncogenes, and tumor-suppressor genes, all of which dictate their protein levels depending on the micro-environmental conditions and the type of cancer cell, favoring cancer cell adaptation and growth. In the present review paper, variation in the mRNA and protein levels as well as in the enzyme/ transporter activities of the OxPhos machinery is analyzed. An integral omics approach to mitochondrial energy metabolism pathways may allow for identifying their use as suitable, reliable biomarkers for early detection of cancer development and metastasis, and for envisioned novel, alternative therapies.
    Keywords:  Metabolic biomarker; anti-mitochondrial therapy.; cancer mitochondria; mitochondrial proteins; oxidative phosphorylation
    DOI:  https://doi.org/10.2174/0113895575254320231030051124
  6. Cell Death Dis. 2024 Jul 18. 15(7): 513
    Targeting valine catabolism to inhibit metabolic reprogramming in prostate cancer.
    Charles L Bidgood, Lisa K Philp, Anja Rockstroh, Melanie Lehman, Colleen C Nelson, Martin C Sadowski, Jennifer H Gunter.
      Metabolic reprogramming and energetic rewiring are hallmarks of cancer that fuel disease progression and facilitate therapy evasion. The remodelling of oxidative phosphorylation and enhanced lipogenesis have previously been characterised as key metabolic features of prostate cancer (PCa). Recently, succinate-dependent mitochondrial reprogramming was identified in high-grade prostate tumours, as well as upregulation of the enzymes associated with branched-chain amino acid (BCAA) catabolism. In this study, we hypothesised that the degradation of the BCAAs, particularly valine, may play a critical role in anapleurotic refuelling of the mitochondrial succinate pool, as well as the maintenance of intracellular lipid metabolism. Through the suppression of BCAA availability, we report significantly reduced lipid content, strongly indicating that BCAAs are important lipogenic fuels in PCa. This work also uncovered a novel compensatory mechanism, whereby fatty acid uptake is increased in response to extracellular valine deprivation. Inhibition of valine degradation via suppression of 3-hydroxyisobutyryl-CoA hydrolase (HIBCH) resulted in a selective reduction of malignant prostate cell proliferation, decreased intracellular succinate and impaired cellular respiration. In combination with a comprehensive multi-omic investigation that incorporates next-generation sequencing, metabolomics, and high-content quantitative single-cell imaging, our work highlights a novel therapeutic target for selective inhibition of metabolic reprogramming in PCa.
    DOI:  https://doi.org/10.1038/s41419-024-06893-2
  7. Cancer Res. 2024 Jul 18.
    Targeting the Sodium-Potassium Pump as a Therapeutic Strategy in Acute Myeloid Leukemia.
    Constanze Schneider, Hermes Spaink, Gabriela Alexe, Neekesh V Dharia, Ashleigh Meyer, Lucy A Merickel, Delan Khalid, Sebastian Scheich, Bjorn Haupl, Louis M Staudt, Thomas Oellerich, Kimberly Stegmaier.
      Tissue-specific differences in the expression of paralog genes, which are not essential in most cell types due to the buffering effect of the partner pair, can make for highly selective gene dependencies. To identify selective paralogous targets for acute myeloid leukemia (AML), we integrated the Cancer Dependency Map with numerous datasets characterizing protein-protein interactions, paralog relationships, and gene expression in cancer models. Here, we identified ATP1B3 as a context-specific, paralog-related dependency in AML. ATP1B3, the beta subunit of the sodium-potassium pump (Na/K-ATP pump), interacts with the alpha subunit ATP1A1 to form an essential complex for maintaining cellular homeostasis and membrane potential in all eukaryotic cells. When ATP1B3's paralog ATP1B1 is poorly expressed, elimination of ATP1B3 leads to the destabilization of the Na/K-ATP pump. ATP1B1 expression is regulated through epigenetic silencing in hematopoietic lineage cells both through histone and DNA methylation in the promoter region. Loss of ATP1B3 in AML cells induced cell death in vitro and reduced leukemia burden in vivo, which could be rescued by stabilizing ATP1A1 through overexpression of ATP1B1. ATP1B3 is thus a potential therapeutic target for AML and other hematologic malignancies with low expression of ATP1B1.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-23-3560
  8. Nat Commun. 2024 Jul 16. 15(1): 5980
    Metabolic imaging across scales reveals distinct prostate cancer phenotypes.
    Nikita Sushentsev, Gregory Hamm, Lucy Flint, Daniel Birtles, Aleksandr Zakirov, Jack Richings, Stephanie Ling, Jennifer Y Tan, Mary A McLean, Vinay Ayyappan, Ines Horvat Menih, Cara Brodie, Jodi L Miller, Ian G Mills, Vincent J Gnanapragasam, Anne Y Warren, Simon T Barry, Richard J A Goodwin, Tristan Barrett, Ferdia A Gallagher.
      Hyperpolarised magnetic resonance imaging (HP-13C-MRI) has shown promise as a clinical tool for detecting and characterising prostate cancer. Here we use a range of spatially resolved histological techniques to identify the biological mechanisms underpinning differential [1-13C]lactate labelling between benign and malignant prostate, as well as in tumours containing cribriform and non-cribriform Gleason pattern 4 disease. Here we show that elevated hyperpolarised [1-13C]lactate signal in prostate cancer compared to the benign prostate is primarily driven by increased tumour epithelial cell density and vascularity, rather than differences in epithelial lactate concentration between tumour and normal. We also demonstrate that some tumours of the cribriform subtype may lack [1-13C]lactate labelling, which is explained by lower epithelial lactate dehydrogenase expression, higher mitochondrial pyruvate carrier density, and increased lipid abundance compared to lactate-rich non-cribriform lesions. These findings highlight the potential of combining spatial metabolic imaging tools across scales to identify clinically significant metabolic phenotypes in prostate cancer.
    DOI:  https://doi.org/10.1038/s41467-024-50362-5
  9. iScience. 2024 Jul 19. 27(7): 110185
    Supernumerary proteins of the human mitochondrial ribosomal small subunit are integral for assembly and translation.
    Taru Hilander, Ryan Awadhpersad, Geoffray Monteuuis, Krystyna L Broda, Max Pohjanpelto, Elizabeth Pyman, Sachin Kumar Singh, Tuula A Nyman, Isabelle Crevel, Robert W Taylor, Ann Saada, Diego Balboa, Brendan J Battersby, Christopher B Jackson, Christopher J Carroll.
      Mitochondrial ribosomes (mitoribosomes) have undergone substantial evolutionary structural remodeling accompanied by loss of ribosomal RNA, while acquiring unique protein subunits located on the periphery. We generated CRISPR-mediated knockouts of all 14 unique (mitochondria-specific/supernumerary) human mitoribosomal proteins (snMRPs) in the small subunit to study the effect on mitoribosome assembly and protein synthesis, each leading to a unique mitoribosome assembly defect with variable impact on mitochondrial protein synthesis. Surprisingly, the stability of mS37 was reduced in all our snMRP knockouts of the small and large ribosomal subunits and patient-derived lines with mitoribosome assembly defects. A redox-regulated CX9C motif in mS37 was essential for protein stability, suggesting a potential mechanism to regulate mitochondrial protein synthesis. Together, our findings support a modular assembly of the human mitochondrial small ribosomal subunit mediated by essential supernumerary subunits and identify a redox regulatory role involving mS37 in mitochondrial protein synthesis in health and disease.
    Keywords:  biochemistry; biological sciences; cell biology; molecular biology
    DOI:  https://doi.org/10.1016/j.isci.2024.110185
  10. Cell Rep. 2024 Jul 13. pii: S2211-1247(24)00836-2. [Epub ahead of print]43(7): 114507
    Tumor suppressor KEAP1 promotes HSPA9 degradation, controlling mitochondrial biogenesis in breast cancer.
    Bing Han, Fang Zhen, Yue Sun, Bin Sun, Hong-Yi Wang, Wei Liu, Jian Huang, Xiao Liang, Ya-Ru Wang, Xue-Song Chen, Shui-Jie Li, Jing Hu.
      The oxidative-stress-related protein Kelch-like ECH-associated protein 1 (KEAP1) is a substrate articulator of E3 ubiquitin ligase, which plays an important role in the ubiquitination modification of proteins. However, the function of KEAP1 in breast cancer and its impact on the survival of patients with breast cancer remain unclear. Our study demonstrates that KEAP1, a positive prognostic factor, plays a crucial role in regulating cell proliferation, apoptosis, and cell cycle transition in breast cancer. We investigate the underlying mechanism using human tumor tissues, high-throughput detection technology, and a mouse xenograft tumor model. KEAP1 serves as a key regulator of cellular metabolism, the reprogramming of which is one of the hallmarks of tumorigenesis. KEAP1 has a significant effect on mitochondrial biogenesis and oxidative phosphorylation by regulating HSPA9 ubiquitination and degradation. These results suggest that KEAP1 could serve as a potential biomarker and therapeutic target in the treatment of breast cancer.
    Keywords:  CP: Cancer; CP: Cell biology
    DOI:  https://doi.org/10.1016/j.celrep.2024.114507
  11. Eur J Haematol. 2024 Jul 18.
    Real-world effectiveness of first-line azacitidine or decitabine with or without venetoclax in acute myeloid leukemia patients unfit for intensive therapy.
    Fabian Acker, Jörg Chromik, Emily Tiedjen, Sebastian Wolf, Jonas B Vischedyk, Philipp Makowka, Julius C Enßle, Khouloud Kouidri, Martin Sebastian, Björn Steffen, Thomas Oellerich, Hubert Serve, Andreas Neubauer, Jonas A Schäfer, Jörg T Bittenbring.
       BACKGROUND: First-line treatment in patients with acute myeloid leukemia (AML) unfit for intensive therapy is the combination of a hypomethylating agent (HMA) with venetoclax (VEN). However, retrospective data confirming the benefits of this regimen outside of clinical trials have shown conflicting results.
    METHODS: We performed a multicenter retrospective analysis of outcomes with first-line HMA-VEN versus HMA in AML patients unfit for intensive chemotherapy.
    RESULTS: A total of 213 patients were included from three German hospitals (125 HMA-VEN, 88 HMA). Median overall survival in the HMA-VEN cohort was 7.9 months (95% confidence interval [CI], 5.1-14.7) versus 4.9 months (3.1-7.1) with HMA. After 1 year, 42% (95% CI, 33-54) and 19% (12-30) of patients were alive, respectively (hazard ratio [HR] for death, 0.64; 95% CI, 0.46-0.88). After adjusting for clinical and molecular baseline characteristics, treatment with HMA-VEN remained significantly associated with both prolonged survival (HR, 0.48; 95% CI, 0.29-0.77) and time to next treatment (HR, 0.63; 95% CI, 0.47-0.85). Patients who achieved recovery of peripheral blood counts had a favorable prognosis (HR for death, 0.52; 95% CI, 0.33-0.84).
    DISCUSSION: These data align with findings from the pivotal VIALE-A trial and support the use of HMA-VEN in patients unfit for intensive therapy.
    Keywords:  AML; azacitidine; decitabine; hypomethylating agent; real‐world data; venetoclax
    DOI:  https://doi.org/10.1111/ejh.14278
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