bims-mibica Biomed News
on Mitochondrial bioenergetics in cancer
Issue of 2024–08–18
sixteen papers selected by
Kelsey Fisher-Wellman, Wake Forest University
  1. Mitochondrial complex I promotes kidney cancer metastasis.
  2. Mitochondrial Probe for Glutathione Depletion Reveals NME3 Essentiality for Mitochondrial Redox Response.
  3. Mitochondrial-derived compartments remove surplus proteins from the outer mitochondrial membrane.
  4. Mitochondrial-derived compartments are multilamellar domains that encase membrane cargo and cytosol.
  5. ACLY and ACSS2 link nutrient-dependent chromatin accessibility to CD8 T cell effector responses.
  6. Defective mitochondrial COX1 translation due to loss of COX14 function triggers ROS-induced inflammation in mouse liver.
  7. Mitochondrial permeability transition dictates mitochondrial maturation upon switch in cellular identity of hematopoietic precursors.
  8. Mfn2 induces NCLX-mediated calcium release from mitochondria.
  9. OPA1 promotes ferroptosis by augmenting mitochondrial ROS and suppressing an integrated stress response.
  10. Hypoxia decreases mitochondrial ROS production in cells.
  11. TFE3 fusions direct an oncogenic transcriptional program that drives OXPHOS and unveils vulnerabilities in translocation renal cell carcinoma.
  12. Targeting BCL2 with Venetoclax Enhances the Efficacy of the KRASG12D Inhibitor MRTX1133 in Pancreatic Cancer.
  13. Mitochondrial Ca 2+ controls pancreatic cancer growth and metastasis by regulating epithelial cell plasticity.
  14. Deregulation of mitochondrial gene expression in cancer: mechanisms and therapeutic opportunities.
  15. Development and validation of prognostic signatures of NAD+ metabolism and immune-related genes in colorectal cancer.
  16. A systematic review of venetoclax for the treatment of unfit AML patients in real-world: is all that glitters gold?
  1. Nature. 2024 Aug 14.
    Mitochondrial complex I promotes kidney cancer metastasis.
    Divya Bezwada, Luigi Perelli, Nicholas P Lesner, Ling Cai, Bailey Brooks, Zheng Wu, Hieu S Vu, Varun Sondhi, Daniel L Cassidy, Stacy Kasitinon, Sherwin Kelekar, Feng Cai, Arin B Aurora, McKenzie Patrick, Ashley Leach, Rashed Ghandour, Yuanyuan Zhang, Duyen Do, Phyllis McDaniel, Jessica Sudderth, Dennis Dumesnil, Sara House, Tracy Rosales, Alan M Poole, Yair Lotan, Solomon Woldu, Aditya Bagrodia, Xiaosong Meng, Jeffrey A Cadeddu, Prashant Mishra, Javier Garcia-Bermudez, Ivan Pedrosa, Payal Kapur, Kevin D Courtney, Craig R Malloy, Giannicola Genovese, Vitaly Margulis, Ralph J DeBerardinis.
      Most kidney cancers are metabolically dysfunctional1-4, but how this dysfunction affects cancer progression in humans is unknown. We infused 13C-labelled nutrients in over 80 patients with kidney cancer during surgical tumour resection. Labelling from [U-13C]glucose varies across subtypes, indicating that the kidney environment alone cannot account for all tumour metabolic reprogramming. Compared with the adjacent kidney, clear cell renal cell carcinomas (ccRCCs) display suppressed labelling of tricarboxylic acid (TCA) cycle intermediates in vivo and in ex vivo organotypic cultures, indicating that suppressed labelling is tissue intrinsic. [1,2-13C]acetate and [U-13C]glutamine infusions in patients, coupled with measurements of respiration in isolated human kidney and tumour mitochondria, reveal lower electron transport chain activity in ccRCCs that contributes to decreased oxidative and enhanced reductive TCA cycle labelling. However, ccRCC metastases unexpectedly have enhanced TCA cycle labelling compared with that of primary ccRCCs, indicating a divergent metabolic program during metastasis in patients. In mice, stimulating respiration or NADH recycling in kidney cancer cells is sufficient to promote metastasis, whereas inhibiting electron transport chain complex I decreases metastasis. These findings in humans and mice indicate that metabolic properties and liabilities evolve during kidney cancer progression, and that mitochondrial function is limiting for metastasis but not growth at the original site.
    DOI:  https://doi.org/10.1038/s41586-024-07812-3
  2. ACS Chem Biol. 2024 Aug 12.
    Mitochondrial Probe for Glutathione Depletion Reveals NME3 Essentiality for Mitochondrial Redox Response.
    Piriththiv Dhavarasa, Tanja Sack, Carmine P Cerrato, Ashley P Cheng, Yi Y Zhang, Kangfu Chen, Shana O Kelley.
      Maintenance of the mitochondrial thiol redox state is essential for cell survival. However, we lack a comprehensive understanding of the redox response to mitochondrial glutathione depletion. We developed a mitochondria-penetrating peptide, mtCDNB, to specifically deplete mitochondrial glutathione. A genome-wide CRISPR/Cas9 screen in tandem with mtCDNB treatment was employed to uncover regulators of the redox response to mitochondrial glutathione depletion. We identified nucleoside diphosphate kinase 3 (NME3) as a regulator of mitochondrial dynamics. We show that NME3 is recruited to the mitochondrial outer membrane when under redox stress. In the absence of NME3, there is impaired mitophagy, which leads to the accumulation of dysfunctional mitochondria. NME3 knockouts depleted of mitochondrial glutathione have increased mitochondrial ROS production, accumulate mtDNA lesions, and present a senescence-associated secretory phenotype. Our findings suggest a novel role for NME3 in selecting mitochondria for degradation through mitophagy under conditions of mitochondrial redox stress.
    DOI:  https://doi.org/10.1021/acschembio.4c00287
  3. J Cell Biol. 2024 Nov 04. pii: e202307036. [Epub ahead of print]223(11):
    Mitochondrial-derived compartments remove surplus proteins from the outer mitochondrial membrane.
    Zachary N Wilson, Sai Sangeetha Balasubramaniam, Sara Wong, Max-Hinderk Schuler, Mitchell J Wopat, Adam L Hughes.
      The outer mitochondrial membrane (OMM) creates a boundary that imports most of the mitochondrial proteome while removing extraneous or damaged proteins. How the OMM senses aberrant proteins and remodels to maintain OMM integrity remains unresolved. Previously, we identified a mitochondrial remodeling mechanism called the mitochondrial-derived compartment (MDC) that removes a subset of the mitochondrial proteome. Here, we show that MDCs specifically sequester proteins localized only at the OMM, providing an explanation for how select mitochondrial proteins are incorporated into MDCs. Remarkably, selective sorting into MDCs also occurs within the OMM, as subunits of the translocase of the outer membrane (TOM) complex are excluded from MDCs unless assembly of the TOM complex is impaired. Considering that overloading the OMM with mitochondrial membrane proteins or mistargeted tail-anchored membrane proteins induces MDCs to form and sequester these proteins, we propose that one functional role of MDCs is to create an OMM-enriched trap that segregates and sequesters excess proteins from the mitochondrial surface.
    DOI:  https://doi.org/10.1083/jcb.202307036
  4. J Cell Biol. 2024 Nov 04. pii: e202307035. [Epub ahead of print]223(11):
    Mitochondrial-derived compartments are multilamellar domains that encase membrane cargo and cytosol.
    Zachary N Wilson, Matt West, Alyssa M English, Greg Odorizzi, Adam L Hughes.
      Preserving the health of the mitochondrial network is critical to cell viability and longevity. To do so, mitochondria employ several membrane remodeling mechanisms, including the formation of mitochondrial-derived vesicles (MDVs) and compartments (MDCs) to selectively remove portions of the organelle. In contrast to well-characterized MDVs, the distinguishing features of MDC formation and composition remain unclear. Here, we used electron tomography to observe that MDCs form as large, multilamellar domains that generate concentric spherical compartments emerging from mitochondrial tubules at ER-mitochondria contact sites. Time-lapse fluorescence microscopy of MDC biogenesis revealed that mitochondrial membrane extensions repeatedly elongate, coalesce, and invaginate to form these compartments that encase multiple layers of membrane. As such, MDCs strongly sequester portions of the outer mitochondrial membrane, securing membrane cargo into a protected domain, while also enclosing cytosolic material within the MDC lumen. Collectively, our results provide a model for MDC formation and describe key features that distinguish MDCs from other previously identified mitochondrial structures and cargo-sorting domains.
    DOI:  https://doi.org/10.1083/jcb.202307035
  5. J Exp Med. 2024 Sep 02. pii: e20231820. [Epub ahead of print]221(9):
    ACLY and ACSS2 link nutrient-dependent chromatin accessibility to CD8 T cell effector responses.
    Irem Kaymak, McLane J Watson, Brandon M Oswald, Shixin Ma, Benjamin K Johnson, Lisa M DeCamp, Batsirai M Mabvakure, Katarzyna M Luda, Eric H Ma, Kin Lau, Zhen Fu, Brejnev Muhire, Susan M Kitchen-Goosen, Alexandra Vander Ark, Michael S Dahabieh, Bozena Samborska, Matthew Vos, Hui Shen, Zi Peng Fan, Thomas P Roddy, Gillian A Kingsbury, Cristovão M Sousa, Connie M Krawczyk, Kelsey S Williams, Ryan D Sheldon, Susan M Kaech, Dominic G Roy, Russell G Jones.
      Coordination of cellular metabolism is essential for optimal T cell responses. Here, we identify cytosolic acetyl-CoA production as an essential metabolic node for CD8 T cell function in vivo. We show that CD8 T cell responses to infection depend on acetyl-CoA derived from citrate via the enzyme ATP citrate lyase (ACLY). However, ablation of ACLY triggers an alternative, acetate-dependent pathway for acetyl-CoA production mediated by acyl-CoA synthetase short-chain family member 2 (ACSS2). Mechanistically, acetate fuels both the TCA cycle and cytosolic acetyl-CoA production, impacting T cell effector responses, acetate-dependent histone acetylation, and chromatin accessibility at effector gene loci. When ACLY is functional, ACSS2 is not required, suggesting acetate is not an obligate metabolic substrate for CD8 T cell function. However, loss of ACLY renders CD8 T cells dependent on acetate (via ACSS2) to maintain acetyl-CoA production and effector function. Together, ACLY and ACSS2 coordinate cytosolic acetyl-CoA production in CD8 T cells to maintain chromatin accessibility and T cell effector function.
    DOI:  https://doi.org/10.1084/jem.20231820
  6. Nat Commun. 2024 Aug 12. 15(1): 6914
    Defective mitochondrial COX1 translation due to loss of COX14 function triggers ROS-induced inflammation in mouse liver.
    Abhishek Aich, Angela Boshnakovska, Steffen Witte, Tanja Gall, Kerstin Unthan-Fechner, Roya Yousefi, Arpita Chowdhury, Drishan Dahal, Aditi Methi, Svenja Kaufmann, Ivan Silbern, Jan Prochazka, Zuzana Nichtova, Marcela Palkova, Miles Raishbrook, Gizela Koubkova, Radislav Sedlacek, Simon E Tröder, Branko Zevnik, Dietmar Riedel, Susann Michanski, Wiebke Möbius, Philipp Ströbel, Christian Lüchtenborg, Patrick Giavalisco, Henning Urlaub, Andre Fischer, Britta Brügger, Stefan Jakobs, Peter Rehling.
      Mitochondrial oxidative phosphorylation (OXPHOS) fuels cellular ATP demands. OXPHOS defects lead to severe human disorders with unexplained tissue specific pathologies. Mitochondrial gene expression is essential for OXPHOS biogenesis since core subunits of the complexes are mitochondrial-encoded. COX14 is required for translation of COX1, the central mitochondrial-encoded subunit of complex IV. Here we describe a COX14 mutant mouse corresponding to a patient with complex IV deficiency. COX14M19I mice display broad tissue-specific pathologies. A hallmark phenotype is severe liver inflammation linked to release of mitochondrial RNA into the cytosol sensed by RIG-1 pathway. We find that mitochondrial RNA release is triggered by increased reactive oxygen species production in the deficiency of complex IV. Additionally, we describe a COA3Y72C mouse, affected in an assembly factor that cooperates with COX14 in early COX1 biogenesis, which displays a similar yet milder inflammatory phenotype. Our study provides insight into a link between defective mitochondrial gene expression and tissue-specific inflammation.
    DOI:  https://doi.org/10.1038/s41467-024-51109-y
  7. Commun Biol. 2024 Aug 09. 7(1): 967
    Mitochondrial permeability transition dictates mitochondrial maturation upon switch in cellular identity of hematopoietic precursors.
    Sandeep P Dumbali, Paulina D Horton, Travis I Moore, Pamela L Wenzel.
      The mitochondrial permeability transition pore (mPTP) is a supramolecular channel that regulates exchange of solutes across cristae membranes, with executive roles in mitochondrial function and cell death. The contribution of the mPTP to normal physiology remains debated, although evidence implicates the mPTP in mitochondrial inner membrane remodeling in differentiating progenitor cells. Here, we demonstrate that strict control over mPTP conductance shapes metabolic machinery as cells transit toward hematopoietic identity. Cells undergoing the endothelial-to-hematopoietic transition (EHT) tightly control chief regulatory elements of the mPTP. During EHT, maturing arterial endothelium restricts mPTP activity just prior to hematopoietic commitment. After transition in cellular identity, mPTP conductance is restored. In utero treatment with NIM811, a molecule that blocks sensitization of the mPTP to opening by Cyclophilin D (CypD), amplifies oxidative phosphorylation (OXPHOS) in hematopoietic precursors and increases hematopoiesis in the embryo. Additionally, differentiating pluripotent stem cells (PSCs) acquire greater organization of mitochondrial cristae and hematopoietic activity following knockdown of the CypD gene, Ppif. Conversely, knockdown of Opa1, a GTPase critical for proper cristae architecture, induces cristae irregularity and impairs hematopoiesis. These data elucidate a mechanism that regulates mitochondrial maturation in hematopoietic precursors and underscore a role for the mPTP in the acquisition of hematopoietic fate.
    DOI:  https://doi.org/10.1038/s42003-024-06671-y
  8. bioRxiv. 2024 Aug 13. pii: 2024.08.05.606704. [Epub ahead of print]
    Mfn2 induces NCLX-mediated calcium release from mitochondria.
    Panagiota Kolitsida, Akash Saha, Andrew W Caliri, Essam Assali, Alejandro Martorell Riera, Samuel Itskanov, Catalina S Magana, Bjorn Stork, Orian S Shirihai, Israel Sekler, Carla M Koehler, Alexander M van der Bliek.
      Mfn2 is a mitochondrial outer membrane fusion protein with the additional role of tethering mitochondria to the ER. Here, we describe a novel connection between Mfn2 and calcium release from mitochondria. We show that Mfn2 controls the mitochondrial inner membrane sodium-calcium exchange protein NCLX, which is a major source for calcium release from mitochondria. This discovery was made with the fungal toxin Phomoxanthone (PXA), which induces calcium release from mitochondria. PXA-induced calcium release is blocked by a chemical inhibitor of NCLX, while NCLX and Mfn2 deletions both also prevent PXA-induced calcium release. CETSA experiments show that PXA directly targets Mfn2, which likely controls NCLX through physical interactions since co-immunoprecipitation and proximity ligation assays show increased association between Mfn2 and NCLX upon treatment with PXA. Interactions between Mfn2 and NCLX also increase when cells are treated with mitochondrial ROS-inducing conditions, such as oligomycin treatment of respiring cells, while the interactions do not increase in Oma1 -/- cells. It seems likely that opening of cristae by Oma1-mediated cleavage of Opa1 promotes translocation of NCLX from cristae to the rim where it can come into contact with Mfn2 thus promoting PXA-induced calcium release from mitochondria. These results therefore delineate a pathway that connects ROS produced inside mitochondria with calcium release and signaling in the cytosol.
    DOI:  https://doi.org/10.1101/2024.08.05.606704
  9. Mol Cell. 2024 Aug 09. pii: S1097-2765(24)00618-X. [Epub ahead of print]
    OPA1 promotes ferroptosis by augmenting mitochondrial ROS and suppressing an integrated stress response.
    Felix G Liang, Fereshteh Zandkarimi, Jaehoon Lee, Joshua L Axelrod, Ryan Pekson, Yisang Yoon, Brent R Stockwell, Richard N Kitsis.
      Ferroptosis, an iron-dependent form of nonapoptotic cell death mediated by lipid peroxidation, has been implicated in the pathogenesis of multiple diseases. Subcellular organelles play pivotal roles in the regulation of ferroptosis, but the mechanisms underlying the contributions of the mitochondria remain poorly defined. Optic atrophy 1 (OPA1) is a mitochondrial dynamin-like GTPase that controls mitochondrial morphogenesis, fusion, and energetics. Here, we report that human and mouse cells lacking OPA1 are markedly resistant to ferroptosis. Reconstitution with OPA1 mutants demonstrates that ferroptosis sensitization requires the GTPase activity but is independent of OPA1-mediated mitochondrial fusion. Mechanistically, OPA1 confers susceptibility to ferroptosis by maintaining mitochondrial homeostasis and function, which contributes both to the generation of mitochondrial lipid reactive oxygen species (ROS) and suppression of an ATF4-mediated integrated stress response. Together, these results identify an OPA1-controlled mitochondrial axis of ferroptosis regulation and provide mechanistic insights for therapeutically manipulating this form of cell death in diseases.
    Keywords:  ATF4; GPx4; OPA1; cell death; ferroptosis; integrated stress response; mitochondria; system X(c)(−); xCT
    DOI:  https://doi.org/10.1016/j.molcel.2024.07.020
  10. Free Radic Biol Med. 2024 Aug 13. pii: S0891-5849(24)00603-8. [Epub ahead of print]224 1-8
    Hypoxia decreases mitochondrial ROS production in cells.
    Bijoya Sen, Bérengère Benoit, Martin D Brand.
      We re-examined the reported increase in mitochondrial ROS production during acute hypoxia in cells. Using the Amplex Ultrared/horseradish peroxidase assay we found a decrease, not increase, in hydrogen peroxide release from HEK293 cells under acute hypoxia, at times ranging from 1 min to 3 h. The rates of superoxide/hydrogen peroxide production from each of the three major sites (site IQ in complex I and site IIIQo in complex III in mitochondria, and NADH oxidases (NOX) in the cytosol) were decreased to the same extent by acute hypoxia, with no change in the cells' ability to degrade added hydrogen peroxide. A similar decrease in ROS production under acute hypoxia was found using the diacetyldichlorofluorescein assay. Using a HIF1α reporter cell line we confirmed earlier observations that suppression of superoxide production by site IIIQo decreases HIF1α expression, and found similar effects of suppressing site IQ or NOX. We conclude that increased mitochondrial ROS do not drive the response of HIF1α to acute hypoxia, but suggest that cytosolic H2O2 derived from site IQ, site IIIQo and NOX in cells is necessary to permit HIF1α stabilization by other signals.
    Keywords:  HEK293; HIF1α; Hydrogen peroxide; NOX; Oxygen concentration; Reactive oxygen species; S1QEL; S3QEL; Superoxide
    DOI:  https://doi.org/10.1016/j.freeradbiomed.2024.08.016
  11. bioRxiv. 2024 Aug 10. pii: 2024.08.09.607311. [Epub ahead of print]
    TFE3 fusions direct an oncogenic transcriptional program that drives OXPHOS and unveils vulnerabilities in translocation renal cell carcinoma.
    Jiao Li, Kaimeng Huang, Fiona McBride, Ananthan Sadagopan, Daniel S Gallant, Meha Thakur, Prateek Khanna, Bingchen Li, Maolin Ge, Cary N Weiss, Mingkee Achom, Qingru Xu, Kun Huang, Birgitta A Ryback, Miao Gui, Liron Bar-Peled, Srinivas R Viswanathan.
      Translocation renal cell carcinoma (tRCC) is an aggressive subtype of kidney cancer driven by TFE3 gene fusions, which act via poorly characterized downstream mechanisms. Here we report that TFE3 fusions transcriptionally rewire tRCCs toward oxidative phosphorylation (OXPHOS), contrasting with the highly glycolytic metabolism of most other renal cancers. This TFE3 fusion-driven OXPHOS program, together with heightened glutathione levels found in renal cancers, renders tRCCs sensitive to reductive stress - a metabolic stress state induced by an imbalance of reducing equivalents. Genome-scale CRISPR screening identifies tRCC-selective vulnerabilities linked to this metabolic state, including EGLN1 , which hydroxylates HIF-1α and targets it for proteolysis. Inhibition of EGLN1 compromises tRCC cell growth by stabilizing HIF-1a and promoting metabolic reprogramming away from OXPHOS, thus representing a vulnerability to OXPHOS-dependent tRCC cells. Our study defines a distinctive tRCC-essential metabolic program driven by TFE3 fusions and nominates EGLN1 inhibition as a therapeutic strategy to counteract fusion-induced metabolic rewiring.
    DOI:  https://doi.org/10.1101/2024.08.09.607311
  12. Cancer Res. 2024 Aug 13.
    Targeting BCL2 with Venetoclax Enhances the Efficacy of the KRASG12D Inhibitor MRTX1133 in Pancreatic Cancer.
    Jeffrey H Becker, Anastasia E Metropulos, Christina Spaulding, Alejandra M Marinelarena, Mario A Shields, Daniel R Principe, Thao D Pham, Hidayatullah G Munshi.
      MRTX1133 is currently being evaluated in patients with pancreatic ductal adenocarcinoma (PDAC) tumors harboring a KRASG12D mutation. Combination strategies have the potential to enhance the efficacy of MRTX1133 to further promote cell death and tumor regression. In this study, we demonstrated that MRTX1133 increased the levels of the pro-apoptotic protein BIM in PDAC cells and conferred sensitivity to the FDA-approved BCL2 inhibitor venetoclax. Combined treatment with MRTX1133 and venetoclax resulted in cell death and growth suppression in 3D cultures. BIM was required for apoptosis induced by the combination treatment. Consistently, BIM was induced in tumors treated with MRTX1133, and venetoclax enhanced the efficacy of MRTX1133 in vivo. Venetoclax could also re-sensitize MRTX1133-resistant PDAC cells to MRTX1133 in 3D cultures, and tumors established from resistant cells responded to the combination of MRTX1133 and venetoclax. These results provide a rationale for the clinical testing of MRTX1133 and venetoclax in PDAC patients.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-23-3574
  13. bioRxiv. 2024 Aug 09. pii: 2024.08.08.607195. [Epub ahead of print]
    Mitochondrial Ca 2+ controls pancreatic cancer growth and metastasis by regulating epithelial cell plasticity.
    Jillian S Weissenrieder, Jessica Peura, Usha Paudel, Nikita Bhalerao, Natalie Weinmann, Calvin Johnson, Maximilian Wengyn, Rebecca Drager, Emma Elizabeth Furth, Karl Simin, Marcus Ruscetti, Ben Z Stanger, Anil K Rustgi, Jason R Pitarresi, J Kevin Foskett.
      Endoplasmic reticulum to mitochondria Ca 2+ transfer is important for cancer cell survival, but the role of mitochondrial Ca 2+ uptake through the mitochondrial Ca 2+ uniporter (MCU) in pancreatic adenocarcinoma (PDAC) is poorly understood. Here, we show that increased MCU expression is associated with malignancy and poorer outcomes in PDAC patients. In isogenic murine PDAC models, Mcu deletion ( Mcu KO ) ablated mitochondrial Ca 2+ uptake, which reduced proliferation and inhibited self-renewal. Orthotopic implantation of MCU-null tumor cells reduced primary tumor growth and metastasis. Mcu deletion reduced the cellular plasticity of tumor cells by inhibiting epithelial-to-mesenchymal transition (EMT), which contributes to metastatic competency in PDAC. Mechanistically, the loss of mitochondrial Ca 2+ uptake reduced expression of the key EMT transcription factor Snail and secretion of the EMT-inducing ligand TGFβ. Snail re-expression and TGFβ treatment rescued deficits in Mcu KO cells and restored their metastatic ability. Thus, MCU may present a therapeutic target in PDAC to limit cancer-cell-induced EMT and metastasis.
    DOI:  https://doi.org/10.1101/2024.08.08.607195
  14. Br J Cancer. 2024 Aug 14.
    Deregulation of mitochondrial gene expression in cancer: mechanisms and therapeutic opportunities.
    Mariah J Berner, Steven W Wall, Gloria V Echeverria.
      "Reprogramming of energy metabolism" was first considered an emerging hallmark of cancer in 2011 by Hanahan & Weinberg and is now considered a core hallmark of cancer. Mitochondria are the hubs of metabolism, crucial for energetic functions and cellular homeostasis. The mitochondrion's bacterial origin and preservation of their own genome, which encodes proteins and RNAs essential to their function, make them unique organelles. Successful generation of mitochondrial gene products requires coordinated functioning of the mitochondrial 'central dogma,' encompassing all steps necessary for mtDNA to yield mitochondrial proteins. Each of these processes has several levels of regulation, including mtDNA accessibility and protection through mtDNA packaging and epigenetic modifications, mtDNA copy number through mitochondrial replication, mitochondrial transcription through mitochondrial transcription factors, and mitochondrial translation through mitoribosome formation. Deregulation of these mitochondrial processes in the context of cancers has only recently been appreciated, with most studies being correlative in nature. Nonetheless, numerous significant associations of the mitochondrial central dogma with pro-tumor phenotypes have been documented. Several studies have even provided mechanistic insights and further demonstrated successful pharmacologic targeting strategies. Based on the emergent importance of mitochondria for cancer biology and therapeutics, it is becoming increasingly important that we gain an understanding of the underpinning mechanisms so they can be successfully therapeutically targeted. It is expected that this mechanistic understanding will result in mitochondria-targeting approaches that balance anticancer potency with normal cell toxicity. This review will focus on current evidence for the dysregulation of mitochondrial gene expression in cancers, as well as therapeutic opportunities on the horizon.
    DOI:  https://doi.org/10.1038/s41416-024-02817-1
  15. Heliyon. 2024 Jul 30. 10(14): e34403
    Development and validation of prognostic signatures of NAD+ metabolism and immune-related genes in colorectal cancer.
    Tao Ye, Hong Huang, Kangli Chen, Yuanao Yu, Dongqin Yue, Li Jiang, Huixian Wu, Ning Zhang.
       Background: Colorectal cancer (CRC) is a prevalent cause of death from malignant tumors. This study aimed to develop a nicotinamide adenine dinucleotide (NAD+) metabolism and immune-related prognostic signature, providing a theoretical foundation for prognosis and therapy in CRC patients.
    Methods: NAD + metabolism-related and immune-related subtypes of CRC patients were identified by consistent clustering. Differentially expressed genes (DEGs) between the two subtypes of CRC were identified by overlapping. A risk signature was constructed using univariate Cox and least absolute shrinkage and selection operator (LASSO) regression analyses. Independent prognostic predictors were authenticated by Cox analysis. Gene set variation analysis (GSVA) and single-sample gene set enrichment analysis (ssGSEA) were applied to investigate the connection between the prognostic signature and the immune microenvironment. Chemotherapy drug sensitivity and immunotherapy responsiveness were projected using the 'pRRophetic' package and Tumor Immune Dysfunction and Exclusion (TIDE) website. The Human Protein Atlas (HPA) database was used to assess the protein expression of prognostic genes in CRC and normal tissues.
    Results: Using bioinformatics methods, three prognostic genes related to immune-related NAD + metabolism were identified, and the results were used to establish and verify a prognostic signature related to immune-related NAD + metabolism in CRC patients. Cox regression analysis confirmed that the risk score was a reliable independent prognostic predictor. GSVA and ssGSEA indicated that the prognostic signature was associated with the immune microenvironment. TIDE analysis suggested that the signature might act as an immunotherapy predictor. Chemotherapy sensitivity analysis revealed that COMP was correlated with chemotherapy sensitivity in CRC patients and might be a potential therapeutic target.
    Conclusion: This study identified NAD + metabolism-immune-related prognostic genes (MOGAT2, COMP, and DNASE1L3) and developed a prognostic signature for CRC prognosis, which is significant for clinical prognosis prediction and treatment strategy decisions for CRC patients.
    Keywords:  Colorectal cancer; Immune-related genes; NAD+ metabolism-related genes; Prognostic signature
    DOI:  https://doi.org/10.1016/j.heliyon.2024.e34403
  16. Ann Hematol. 2024 Aug 16.
    A systematic review of venetoclax for the treatment of unfit AML patients in real-world: is all that glitters gold?
    Antonio Solana-Altabella, Rebeca Rodríguez-Veiga, David Martínez-Cuadrón, Pau Montesinos.
      Acute myeloid leukemia (AML) is an aggressive hematological disease that mainly affects elderly patients. Following the randomized VIALE-A trial, current standard treatment in patients who are not candidates for intensive chemotherapy consists of the combination of venetoclax (VEN), a selective inhibitor of the anti-apoptotic protein BCL-2, with azacitidine (AZA) or decitabine (DEC). We performed a systematic review to critically assess the growing existing evidence regarding the effectiveness of the VEN-based combinations in unfit adult patients with newly diagnosed AML in the real-world setting. Following PRISMA guidelines, a systematic search of published manuscripts and conference abstracts (European Hematology Association and American Society of Hematology) was conducted (updated March 2024). Primary outcomes were composite complete remission (CRc) and median overall survival (mOS). A total of 73 studies fulfilled inclusion criteria, with a median age of 73 years old. The weighted mean mOS was 10.3 months among 7 138 patients, significantly lower than expected according to the VIALE-A trial (14.7 months), while the weighted mean CRc rate was 58.2% among 5 831 patients, slightly lower to that reported in the VIALE-A (66.4%). Early death rates at 30 and 60 days were 5% and 13%, respectively. The weighted mean percentage of subsequent allogeneic transplant was 15.4%. In conclusion, breakthrough mOS reported in the VIALE-A trial using VEN-AZA was not well reproduced in real world for unfit newly diagnosed AML patients, while CRc rates were more consistent. Strategies to optimize patient selection, dosing regimens, and supportive care are crucial to improve outcomes in real-world.
    Keywords:  AML; Newly diagnosed; Real-world; Unfit; Venetoclax
    DOI:  https://doi.org/10.1007/s00277-024-05891-w
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