bims-mibica 2024-06-09 papers

bims-mibica

Biomed News

on Mitochondrial bioenergetics in cancer

Issue of 2024–06–09
thirty papers selected by
Kelsey Fisher-Wellman, East Carolina University

Lipid unsaturation promotes BAX and BAK pore activity during apoptosis.
De novo and salvage purine synthesis pathways across tissues and tumors.
Reduced Protein Import via TIM23 SORT Drives Disease Pathology in TIMM50-Associated Mitochondrial Disease.
CPT1A loss disrupts BCAA metabolism to confer therapeutic vulnerability in TP53-mutated liver cancer.
ZBTB11 Depletion Targets Metabolic Vulnerabilities in K-Ras Inhibitor Resistant PDAC.
Functional diversity among cardiolipin binding sites on the mitochondrial ADP/ATP carrier.
UnitedMet harnesses RNA-metabolite covariation to impute metabolite levels in clinical samples.
Suppressing mitochondrial inner membrane protein (IMMT) inhibits the proliferation of breast cancer cells through mitochondrial remodeling and metabolic regulation.
IDH1 inhibition potentiates chemotherapy efficacy in pancreatic cancer.
Ketogenic diet enhances the anti-cancer effects of PD-L1 blockade in renal cell carcinoma.
Heterogeneous distribution of mitochondria and succinate dehydrogenase activity in human airway smooth muscle cells.
Expanding the π-system of fatty acid-anion transporter conjugates modulates their mechanism of proton transport and mitochondrial uncoupling activity.
Nucleotide depletion promotes cell fate transitions by inducing DNA replication stress.
Enhancing tumor-infiltrating T cells with an exclusive fuel source.
A CD36-dependent non-canonical lipid metabolism program promotes immune escape and resistance to hypomethylating agent therapy in AML.
Imaging brain glucose metabolism in vivo reveals propionate as a major anaplerotic substrate in pyruvate dehydrogenase deficiency.
Obesogenic High-Fat Diet and MYC Cooperate to Promote Lactate Accumulation and Tumor Microenvironment Remodeling in Prostate Cancer.
A targetable PRR11-DHODH axis drives ferroptosis- and temozolomide-resistance in glioblastoma.
ROS-mediated cytoplasmic localization of CARM1 induces mitochondrial fission through DRP1 methylation.
Hypoxia-mediated repression of pyruvate carboxylase drives immunosuppression.
Mitophagy and cancer: role of BNIP3/BNIP3L as energetic drivers of stemness features, ATP production, proliferation, and cell migration.
Cardiolipin clustering promotes mitochondrial membrane dynamics.
The ubiquitin E3 ligase APC/CCdc20 mediates mitotic degradation of OGT.
Circular RNA circMYLK4 shifts energy metabolism from glycolysis to OXPHOS by binding to the calcium channel auxiliary subunit CACNA2D2.
Extracellular vesicles activated cancer-associated fibroblasts promote lung cancer metastasis through mitophagy and mtDNA transfer.
Cu(II) complex that synergistically potentiates cytotoxicity and an antitumor immune response by targeting cellular redox homeostasis.
Comparative analysis of Bcl-2 family protein overexpression in CAR T cells alone and in combination with BH3 mimetics.
Metabolic reprogramming-driven homologous recombination and TCA cycle dysregulation contribute to poor prognoses in lung adenocarcinoma.
A Comprehensive Prognostic Model for Colon Adenocarcinoma Depending on Nuclear-Mitochondrial-Related Genes.
SLC7A11-mediated cystine import protects against NDUFS7 deficiency-induced cell death in HEK293T cells.

Nat Commun. 2024 Jun 03. 15(1): 4700

Lipid unsaturation promotes BAX and BAK pore activity during apoptosis.

Shashank Dadsena, Rodrigo Cuevas Arenas, Gonçalo Vieira, Susanne Brodesser, Manuel N Melo, Ana J García-Sáez.

BAX and BAK are proapoptotic members of the BCL2 family that directly mediate mitochondrial outer membrane permeabilition (MOMP), a central step in apoptosis execution. However, the molecular architecture of the mitochondrial apoptotic pore remains a key open question and especially little is known about the contribution of lipids to MOMP. By performing a comparative lipidomics analysis of the proximal membrane environment of BAK isolated in lipid nanodiscs, we find a significant enrichment of unsaturated species nearby BAK and BAX in apoptotic conditions. We then demonstrate that unsaturated lipids promote BAX pore activity in model membranes, isolated mitochondria and cellular systems, which is further supported by molecular dynamics simulations. Accordingly, the fatty acid desaturase FADS2 not only enhances apoptosis sensitivity, but also the activation of the cGAS/STING pathway downstream mtDNA release. The correlation of FADS2 levels with the sensitization to apoptosis of different lung and kidney cancer cell lines by co-treatment with unsaturated fatty acids supports the relevance of our findings. Altogether, our work provides an insight on how local lipid environment affects BAX and BAK function during apoptosis.

DOI: https://doi.org/10.1038/s41467-024-49067-6
Cell. 2024 May 30. pii: S0092-8674(24)00520-8. [Epub ahead of print]

De novo and salvage purine synthesis pathways across tissues and tumors.

Diem H Tran, Dohun Kim, Rushendhiran Kesavan, Harrison Brown, Trishna Dey, Mona Hoseini Soflaee, Hieu S Vu, Alpaslan Tasdogan, Jason Guo, Divya Bezwada, Houssam Al Saad, Feng Cai, Ashley Solmonson, Halie Rion, Rawand Chabatya, Salma Merchant, Nathan J Manales, Vanina T Tcheuyap, Megan Mulkey, Thomas P Mathews, James Brugarolas, Sean J Morrison, Hao Zhu, Ralph J DeBerardinis, Gerta Hoxhaj.

  Purine nucleotides are vital for RNA and DNA synthesis, signaling, metabolism, and energy homeostasis. To synthesize purines, cells use two principal routes: the de novo and salvage pathways. Traditionally, it is believed that proliferating cells predominantly rely on de novo synthesis, whereas differentiated tissues favor the salvage pathway. Unexpectedly, we find that adenine and inosine are the most effective circulating precursors for supplying purine nucleotides to tissues and tumors, while hypoxanthine is rapidly catabolized and poorly salvaged in vivo. Quantitative metabolic analysis demonstrates comparative contribution from de novo synthesis and salvage pathways in maintaining purine nucleotide pools in tumors. Notably, feeding mice nucleotides accelerates tumor growth, while inhibiting purine salvage slows down tumor progression, revealing a crucial role of the salvage pathway in tumor metabolism. These findings provide fundamental insights into how normal tissues and tumors maintain purine nucleotides and highlight the significance of purine salvage in cancer.

Keywords:  cancer metabolism; de novo purine synthesis; in vivo isotope tracing; nucleotide diet; nucleotide metabolism; purine bases; purine degradation; purine salvage; tissue; tumor growth

DOI:  https://doi.org/10.1016/j.cell.2024.05.011
Mol Cell Biol. 2024 Jun 03. 1-19

Reduced Protein Import via TIM23 SORT Drives Disease Pathology in TIMM50-Associated Mitochondrial Disease.

Jordan J Crameri, Catherine S Palmer, Tegan Stait, Thomas D Jackson, Matthew Lynch, Adriane Sinclair, Leah E Frajman, Alison G Compton, David Coman, David R Thorburn, Ann E Frazier, Diana Stojanovski.

  TIMM50 is a core subunit of the TIM23 complex, the mitochondrial inner membrane translocase responsible for the import of pre-sequence-containing precursors into the mitochondrial matrix and inner membrane. Here we describe a mitochondrial disease patient who is homozygous for a novel variant in TIMM50 and establish the first proteomic map of mitochondrial disease associated with TIMM50 dysfunction. We demonstrate that TIMM50 pathogenic variants reduce the levels and activity of endogenous TIM23 complex, which significantly impacts the mitochondrial proteome, resulting in a combined oxidative phosphorylation (OXPHOS) defect and changes to mitochondrial ultrastructure. Using proteomic data sets from TIMM50 patient fibroblasts and a TIMM50 HEK293 cell model of disease, we reveal that laterally released substrates imported via the TIM23SORT complex pathway are most sensitive to loss of TIMM50. Proteins involved in OXPHOS and mitochondrial ultrastructure are enriched in the TIM23SORT substrate pool, providing a biochemical mechanism for the specific defects in TIMM50-associated mitochondrial disease patients. These results highlight the power of using proteomics to elucidate molecular mechanisms of disease and uncovering novel features of fundamental biology, with the implication that human TIMM50 may have a more pronounced role in lateral insertion than previously understood.

Keywords:  Mitochondria; TIM23 complex; TIMM50; mitochondrial disease; mitochondrial protein import

DOI:  https://doi.org/10.1080/10985549.2024.2353652
Cancer Lett. 2024 May 31. pii: S0304-3835(24)00400-2. [Epub ahead of print]595 217006

CPT1A loss disrupts BCAA metabolism to confer therapeutic vulnerability in TP53-mutated liver cancer.

Yanfeng Liu, Fan Wang, Guoquan Yan, Yu Tong, Wenyun Guo, Songling Li, Yifei Qian, Qianyu Li, Yu Shu, Lei Zhang, Yonglong Zhang, Qiang Xia.

  Driver genomic mutations in tumors define specific molecular subtypes that display distinct malignancy competence, therapeutic resistance and clinical outcome. Although TP53 mutation has been identified as the most common mutation in hepatocellular carcinoma (HCC), current understanding on the biological traits and therapeutic strategies of this subtype has been largely unknown. Here, we reveal that fatty acid β oxidation (FAO) is remarkable repressed in TP53 mutant HCC and which links to poor prognosis in HCC patients. We further demonstrate that carnitine palmitoyltransferase 1 (CPT1A), the rate-limiting enzyme of FAO, is universally downregulated in liver tumor tissues, and which correlates with poor prognosis in HCC and promotes HCC progression in the de novo liver tumor and xenograft tumor models. Mechanically, hepatic Cpt1a loss disrupts lipid metabolism and acetyl-CoA production. Such reduction in acetyl-CoA reduced histone acetylation and epigenetically reprograms branched-chain amino acids (BCAA) catabolism, and leads to the accumulation of cellular BCAAs and hyperactivation of mTOR signaling. Importantly, we reveal that genetic ablation of CPT1A renders TP53 mutant liver cancer mTOR-addicted and sensitivity to mTOR inhibitor AZD-8055 treatment. Consistently, Cpt1a loss in HCC directs tumor cell therapeutic response to AZD-8055. CONCLUSION: Our results show genetic evidence for CPT1A as a metabolic tumor suppressor in HCC and provide a therapeutic approach for TP53 mutant HCC patients.

Keywords:  BCAA metabolism; CPT1A; Fatty acid β oxidation; Hepatocellular carcinoma; TP53 mutant

DOI:  https://doi.org/10.1016/j.canlet.2024.217006
bioRxiv. 2024 May 21. pii: 2024.05.19.594824. [Epub ahead of print]

ZBTB11 Depletion Targets Metabolic Vulnerabilities in K-Ras Inhibitor Resistant PDAC.

Nathan L Tran, Jiewei Jiang, Min Ma, Gillian E Gadbois, Kevin C M Gulay, Alyssa Verano, Haowen Zhou, Chun-Teng Huang, David A Scott, Anne G Bang, Herve Tiriac, Andrew M Lowy, Eric S Wang, Fleur M Ferguson.

Over 95% of pancreatic ductal adenocarcinomas (PDAC) harbor oncogenic mutations in K-Ras. Upon treatment with K-Ras inhibitors, PDAC cancer cells undergo metabolic reprogramming towards an oxidative phosphorylation-dependent, drug-resistant state. However, direct inhibition of complex I is poorly tolerated in patients due to on-target induction of peripheral neuropathy. In this work, we develop molecular glue degraders against ZBTB11, a C2H2 zinc finger transcription factor that regulates the nuclear transcription of components of the mitoribosome and electron transport chain. Our ZBTB11 degraders leverage the differences in demand for biogenesis of mitochondrial components between human neurons and rapidly-dividing pancreatic cancer cells, to selectively target the K-Ras inhibitor resistant state in PDAC. Combination treatment of both K-Ras inhibitor-resistant cell lines and multidrug resistant patient-derived organoids resulted in superior anti-cancer activity compared to single agent treatment, while sparing hiPSC-derived neurons. Proteomic and stable isotope tracing studies revealed mitoribosome depletion and impairment of the TCA cycle as key events that mediate this response. Together, this work validates ZBTB11 as a vulnerability in K-Ras inhibitor-resistant PDAC and provides a suite of molecular glue degrader tool compounds to investigate its function.

DOI: https://doi.org/10.1101/2024.05.19.594824
EMBO J. 2024 Jun 05.

Functional diversity among cardiolipin binding sites on the mitochondrial ADP/ATP carrier.

Nanami Senoo, Dinesh K Chinthapalli, Matthew G Baile, Vinaya K Golla, Bodhisattwa Saha, Abraham O Oluwole, Oluwaseun B Ogunbona, James A Saba, Teona Munteanu, Yllka Valdez, Kevin Whited, Macie S Sheridan, Dror Chorev, Nathan N Alder, Eric R May, Carol V Robinson, Steven M Claypool.

  Lipid-protein interactions play a multitude of essential roles in membrane homeostasis. Mitochondrial membranes have a unique lipid-protein environment that ensures bioenergetic efficiency. Cardiolipin (CL), the signature mitochondrial lipid, plays multiple roles in promoting oxidative phosphorylation (OXPHOS). In the inner mitochondrial membrane, the ADP/ATP carrier (AAC in yeast; adenine nucleotide translocator, ANT in mammals) exchanges ADP and ATP, enabling OXPHOS. AAC/ANT contains three tightly bound CLs, and these interactions are evolutionarily conserved. Here, we investigated the role of these buried CLs in AAC/ANT using a combination of biochemical approaches, native mass spectrometry, and molecular dynamics simulations. We introduced negatively charged mutations into each CL-binding site of yeast Aac2 and established experimentally that the mutations disrupted the CL interactions. While all mutations destabilized Aac2 tertiary structure, transport activity was impaired in a binding site-specific manner. Additionally, we determined that a disease-associated missense mutation in one CL-binding site in human ANT1 compromised its structure and transport activity, resulting in OXPHOS defects. Our findings highlight the conserved significance of CL in AAC/ANT structure and function, directly tied to specific lipid-protein interactions.

Keywords:  Cardiolipin; Lipid–Protein Interaction; Membrane Transport; Mitochondria; Oxidative Phosphorylation

DOI:  https://doi.org/10.1038/s44318-024-00132-2
medRxiv. 2024 May 25. pii: 2024.05.24.24307903. [Epub ahead of print]

UnitedMet harnesses RNA-metabolite covariation to impute metabolite levels in clinical samples.

Amy X Xie, Wesley Tansey, Ed Reznik.

Comprehensively studying metabolism requires the measurement of metabolite levels. However, in contrast to the broad availability of gene expression data, metabolites are rarely measured in large molecularly-defined cohorts of tissue samples. To address this basic barrier to metabolic discovery, we propose a Bayesian framework ("UnitedMet") which leverages the empirical strength of RNA-metabolite covariation to impute otherwise unmeasured metabolite levels from widely available transcriptomic data. We demonstrate that UnitedMet is equally capable of imputing whole pool sizes as well as the outcomes of isotope tracing experiments. We apply UnitedMet to investigate the metabolic impact of driver mutations in kidney cancer, identifying a novel association between BAP1 and a highly oxidative tumor phenotype. We similarly apply UnitedMet to determine that advanced kidney cancers upregulate oxidative phosphorylation relative to early-stage disease, that oxidative metabolism in kidney cancer is associated with inferior outcomes to combination therapy, and that kidney cancer metastases themselves demonstrate elevated oxidative phosphorylation relative to primary tumors. UnitedMet therefore enables the assessment of metabolic phenotypes in contexts where metabolite measurements were not taken or are otherwise infeasible, opening new avenues for the generation and evaluation of metabolite-centered hypotheses. UnitedMet is open source and publicly available ( https://github.com/reznik-lab/UnitedMet ).

DOI: https://doi.org/10.1101/2024.05.24.24307903
Sci Rep. 2024 06 04. 14(1): 12766

Suppressing mitochondrial inner membrane protein (IMMT) inhibits the proliferation of breast cancer cells through mitochondrial remodeling and metabolic regulation.

Li Liu, Qingqing Zhao, Daigang Xiong, Dan Li, Jie Du, Yunfei Huang, Yan Yang, Rui Chen.

  Metabolic reprogramming is widely recognized as a hallmark of malignant tumors, and the targeting of metabolism has emerged as an appealing approach for cancer treatment. Mitochondria, as pivotal organelles, play a crucial role in the metabolic regulation of tumor cells, and their morphological and functional alterations are intricately linked to the biological characteristics of tumors. As a key regulatory subunit of mitochondria, mitochondrial inner membrane protein (IMMT), plays a vital role in degenerative diseases, but its role in tumor is almost unknown. The objective of this research was to investigate the roles that IMMT play in the development and progression of breast cancer (BC), as well as to elucidate the underlying biological mechanisms that drive these effects. In this study, it was confirmed that the expression of IMMT in BC tissues was significantly higher than that in normal tissues. The analysis of The Cancer Genome Atlas (TCGA) database revealed that IMMT can serve as an independent prognostic factor for BC patients. Additionally, verification in clinical specimens of BC demonstrated a positive association between high IMMT expression and larger tumor size (> 2 cm), Ki-67 expression (> 15%), and HER-2 status. Furthermore, in vitro experiments have substantiated that the suppression of IMMT expression resulted in a reduction in cell proliferation and alterations in mitochondrial cristae, concomitant with the liberation of cytochrome c, but it did not elicit mitochondrial apoptosis. Through Gene Set Enrichment Analysis (GSEA) analysis, we have predicted the associated metabolic genes and discovered that IMMT potentially modulates the advancement of BC through its interaction with 16 metabolic-related genes, and the changes in glycolysis related pathways have been validated in BC cell lines after IMMT inhibition. Consequently, this investigation furnishes compelling evidence supporting the classification of IMMT as prognostic marker in BC, and underscoring its prospective utility as a novel target for metabolic therapy.

Keywords:  Breast cancer; Metabolic reprogramming; Mitochondria remodeling; Mitochondrial inner membrane protein (IMMT); Prognostic marker

DOI:  https://doi.org/10.1038/s41598-024-63427-8
Cancer Res. 2024 Jun 06.

IDH1 inhibition potentiates chemotherapy efficacy in pancreatic cancer.

Mehrdad Zarei, Omid Hajihassani, Jonathan J Hue, Alexander W Loftus, Hallie J Graor, Faith Nakazzi, Parnian Naji, Christina S Boutros, Vinayak Uppin, Ali Vaziri-Gohar, Akram Shalaby, John M Asara, Luke D Rothermel, Jonathan R Brody, Jordan M Winter.

Pancreatic ductal adenocarcinoma (PDAC) is associated with a five-year overall survival rate of just 13%, and development of chemotherapy resistance is nearly universal. PDAC cells overexpress wild-type IDH1 that can enable them to overcome metabolic stress, suggesting it could represent a therapeutic target in PDAC. Here, we found that anti-IDH1 therapy enhanced the efficacy of conventional chemotherapeutics. Chemotherapy treatment induced ROS and increased TCA cycle activity in PDAC cells, along with the induction of wild-type IDH1 expression as a key resistance factor. IDH1 facilitated PDAC survival following chemotherapy treatment by supporting mitochondrial function and antioxidant defense to neutralize reactive oxygen species through the generation of alpha-ketoglutarate and NADPH, respectively. Pharmacologic inhibition of wild-type IDH1 with ivosidenib synergized with conventional chemotherapeutics in vitro and potentiated the efficacy of sub-therapeutic doses of these drugs in vivo in murine PDAC models. This promising treatment approach is translatable through available and safe oral inhibitors and provides the basis of an open and accruing clinical trial testing this combination (NCT05209074).

DOI: https://doi.org/10.1158/0008-5472.CAN-23-1895
Front Endocrinol (Lausanne). 2024 ;15 1344891

Ketogenic diet enhances the anti-cancer effects of PD-L1 blockade in renal cell carcinoma.

Jeremy Richard, Céline Beauvillain, Maxime Benoit, Magalie Barth, Cécile Aubert, Cyrielle Rolley, Sarah Bellal, Jennifer Bourreau, Matthieu Ferragu, Souhil Lebdai, Arnaud Chevrollier, Daniel Henrion, Vincent Procaccio, Pierre Bigot.

   Introduction: Clear cell renal cell carcinoma (ccRCC) is characterized by a predominant metabolic reprogramming triggering energy production by anaerobic glycolysis at the expense of oxydative phosphorylation. Ketogenic diet (KD), which consists of high fat and low carbohydrate intake, could bring required energy substrates to healthy cells while depriving tumor cells of glucose. Our objective was to evaluate the effect of KD on renal cancer cell tumor metabolism and growth proliferation.
Methods: Growth cell proliferation and mitochondrial metabolism of ACHN and Renca renal carcinoma cells were evaluated under ketone bodies (KB) exposure. In vivo studies were performed with mice (nude or Balb/c) receiving a xenograft of ACHN cells or Renca cells, respectively, and were then split into 2 feeding groups, fed either with standard diet or a 2:1 KD ad libitum. To test the effect of KD associated to immunotherapy, Balb/c mice were treated with anti-PDL1 mAb. Tumor growth was monitored.
Results: In vitro, KB exposure was associated with a significant reduction of ACHN and Renca cell proliferation and viability, while increasing mitochondrial metabolism. In mice, KD was associated with tumor growth reduction and PDL-1 gene expression up-regulation. In Balb/c mice adjuvant KD was associated to a better response to anti-PDL-1 mAb treatment.
Conclusion: KB reduced the renal tumor cell growth proliferation and improved mitochondrial respiration and biogenesis. KD also slowed down tumor growth of ACHN and Renca in vivo. We observed that PDL-1 was significantly overexpressed in tumor in mice under KD. Response to anti-PDL-1 mAb was improved in mice under KD. Further studies are needed to confirm the therapeutic benefit of adjuvant KD combined with immunotherapy in patients with kidney cancer.

Keywords:  PDL1; adjuvant ketogenic diet; immunotherapy; metabolic reprogramming; mitochondrial biogenesis; renal cell carcinoma

DOI:  https://doi.org/10.3389/fendo.2024.1344891
FASEB Bioadv. 2024 Jun;6(6): 159-176

Heterogeneous distribution of mitochondria and succinate dehydrogenase activity in human airway smooth muscle cells.

Sanjana Mahadev Bhat, Gary C Sieck.

  Succinate dehydrogenase (SDH) is a key mitochondrial enzyme involved in the tricarboxylic acid cycle, where it facilitates the oxidation of succinate to fumarate, and is coupled to the reduction of ubiquinone in the electron transport chain as Complex II. Previously, we developed a confocal-based quantitative histochemical technique to determine the maximum velocity of the SDH reaction (SDHmax) in single cells and observed that SDHmax corresponds with mitochondrial volume density. In addition, mitochondrial volume and motility varied within different compartments of human airway smooth muscle (hASM) cells. Therefore, we hypothesize that the SDH activity varies relative to the intracellular mitochondrial volume within hASM cells. Using 3D confocal imaging of labeled mitochondria and a concentric shell method for analysis, we quantified mitochondrial volume density, mitochondrial complexity index, and SDHmax relative to the distance from the nuclear membrane. The mitochondria within individual hASM cells were more filamentous in the immediate perinuclear region and were more fragmented in the distal parts of the cell. Within each shell, SDHmax also corresponded to mitochondrial volume density, where both peaked in the perinuclear region and decreased in more distal parts of the cell. Additionally, when normalized to mitochondrial volume, SDHmax was lower in the perinuclear region when compared to the distal parts of the cell. In summary, our results demonstrate that SDHmax measures differences in SDH activity within different cellular compartments. Importantly, our data indicate that mitochondria within individual cells are morphologically heterogeneous, and their distribution varies substantially within different cellular compartments, with distinct functional properties.

Keywords:  airway smooth muscle; confocal microscope; intracellular distribution; mitochondria; succinate dehydrogenase

DOI:  https://doi.org/10.1096/fba.2024-00047
Chemistry. 2024 Jun 05. e202400931

Expanding the π-system of fatty acid-anion transporter conjugates modulates their mechanism of proton transport and mitochondrial uncoupling activity.

Edward York, Daniel A McNaughton, David S Gertner, Philip A Gale, Michael Murray, Tristan Rawling.

  Mitochondrial uncoupling by small molecule protonophores is a promising strategy for developing novel anticancer agents. Recently, aryl urea substituted fatty acids (aryl ureas) were identified as a new class of protonophoric anticancer agents. To mediate proton transport these molecules self-assemble into membrane-permeable anionic dimers in which intermolecular hydrogen bonds between the carboxylate and aryl-urea anion receptor delocalise the negative charge across the aromatic π-system. In this work, we extend the aromatic π-system by introducing a second phenyl substituent to the aryl urea scaffold and compare the proton transport mechanisms and mitochondrial uncoupling actions of these compounds to their monoaryl analogues. It was found that incorporation of meta-linked phenyl substituents into the aryl urea scaffold enhanced proton transport in vesicles and demonstrated superior capacity to depolarise mitochondria, inhibit ATP production and reduce the viability of MDA-MB-231 breast cancer cells. In contrast, diphenyl ureas linked through a 1,4-distribution across the phenyl ring displayed diminished proton transport activity, despite both diphenyl urea isomers possessing similar binding affinities for carboxylates. Mechanistic studies suggest that inclusion of a second aryl ring changes the proton transport mechanism, presumably due to steric factors that impose higher energy penalties for dimer formation.

Keywords:  Anticancer; anion transporter; mitochondrial uncoupling; proton transport

DOI:  https://doi.org/10.1002/chem.202400931
Dev Cell. 2024 May 30. pii: S1534-5807(24)00327-7. [Epub ahead of print]

Nucleotide depletion promotes cell fate transitions by inducing DNA replication stress.

Brian T Do, Peggy P Hsu, Sidney Y Vermeulen, Zhishan Wang, Taghreed Hirz, Keene L Abbott, Najihah Aziz, Joseph M Replogle, Stefan Bjelosevic, Jonathan Paolino, Samantha A Nelson, Samuel Block, Alicia M Darnell, Raphael Ferreira, Hanyu Zhang, Jelena Milosevic, Daniel R Schmidt, Christopher Chidley, Isaac S Harris, Jonathan S Weissman, Yana Pikman, Kimberly Stegmaier, Sihem Cheloufi, Xiaofeng A Su, David B Sykes, Matthew G Vander Heiden.

  Control of cellular identity requires coordination of developmental programs with environmental factors such as nutrient availability, suggesting that perturbing metabolism can alter cell state. Here, we find that nucleotide depletion and DNA replication stress drive differentiation in human and murine normal and transformed hematopoietic systems, including patient-derived acute myeloid leukemia (AML) xenografts. These cell state transitions begin during S phase and are independent of ATR/ATM checkpoint signaling, double-stranded DNA break formation, and changes in cell cycle length. In systems where differentiation is blocked by oncogenic transcription factor expression, replication stress activates primed regulatory loci and induces lineage-appropriate maturation genes despite the persistence of progenitor programs. Altering the baseline cell state by manipulating transcription factor expression causes replication stress to induce genes specific for alternative lineages. The ability of replication stress to selectively activate primed maturation programs across different contexts suggests a general mechanism by which changes in metabolism can promote lineage-appropriate cell state transitions.

Keywords:  cancer; cell fate; cell state; dependencies; differentiation; epigenetics; hematopoiesis; metabolism; nucleotides; replication; replication stress

DOI:  https://doi.org/10.1016/j.devcel.2024.05.010
bioRxiv. 2024 May 21. pii: 2024.05.20.595053. [Epub ahead of print]

Enhancing tumor-infiltrating T cells with an exclusive fuel source.

Matthew L Miller, Rina Nagarajan, Timothy J Thauland, Manish J Butte.

Solid tumors harbor immunosuppressive microenvironments that inhibit tumor infiltrating lymphocytes (TILs) through the voracious consumption of glucose. We sought to restore TIL function by providing them with an exclusive fuel source. The glucose disaccharide cellobiose, which is a building block of cellulose, contains a β-1,4-glycosidic bond that cannot be hydrolyzed by animals (or their tumors), but fungal and bacterial organisms have evolved enzymes to catabolize cellobiose and use the resulting glucose. By equipping T cells with two proteins that enable import and hydrolysis of cellobiose, we demonstrate that supplementation of cellobiose during glucose withdrawal restores T cell cytokine production and cellular proliferation. Murine tumor growth is suppressed and survival is prolonged. Offering exclusive access to a natural disaccharide is a new tool that augments cancer immunotherapies. Beyond cancer, this approach could be used to answer questions about the regulation of glucose metabolism across many cell types, biological processes, and diseases.

DOI: https://doi.org/10.1101/2024.05.20.595053
Cell Rep Med. 2024 May 29. pii: S2666-3791(24)00284-2. [Epub ahead of print] 101592

A CD36-dependent non-canonical lipid metabolism program promotes immune escape and resistance to hypomethylating agent therapy in AML.

He-Zhou Guo, Rui-Xue Feng, Yan-Jie Zhang, Ye-Hua Yu, Wei Lu, Jia-Jia Liu, Shao-Xin Yang, Chong Zhao, Zhao-Li Zhang, Shan-He Yu, Hui Jin, Si-Xuan Qian, Jian-Yong Li, Jiang Zhu, Jun Shi.

Environmental lipids are essential for fueling tumor energetics, but whether these exogenous lipids transported into cancer cells facilitate immune escape remains unclear. Here, we find that CD36, a transporter for exogenous lipids, promotes acute myeloid leukemia (AML) immune evasion. We show that, separately from its established role in lipid oxidation, CD36 on AML cells senses oxidized low-density lipoprotein (OxLDL) to prime the TLR4-LYN-MYD88-nuclear factor κB (NF-κB) pathway, and exogenous palmitate transfer via CD36 further potentiates this innate immune pathway by supporting ZDHHC6-mediated MYD88 palmitoylation. Subsequently, NF-κB drives the expression of immunosuppressive genes that inhibit anti-tumor T cell responses. Notably, high-fat-diet or hypomethylating agent decitabine treatment boosts the immunosuppressive potential of AML cells by hijacking CD36-dependent innate immune signaling, leading to a dampened therapeutic effect. This work is of translational interest because lipid restriction by US Food and Drug Administration (FDA)-approved lipid-lowering statin drugs improves the efficacy of decitabine therapy by weakening leukemic CD36-mediated immunosuppression.

DOI: https://doi.org/10.1016/j.xcrm.2024.101592
Cell Metab. 2024 Jun 04. pii: S1550-4131(24)00178-5. [Epub ahead of print]36(6): 1394-1410.e12

Imaging brain glucose metabolism in vivo reveals propionate as a major anaplerotic substrate in pyruvate dehydrogenase deficiency.

Isaac Marin-Valencia, Arif Kocabas, Carlos Rodriguez-Navas, Vesselin Z Miloushev, Manuel González-Rodríguez, Hannah Lees, Kelly E Henry, Jake Vaynshteyn, Valerie Longo, Kofi Deh, Roozbeh Eskandari, Arsen Mamakhanyan, Marjan Berishaj, Kayvan R Keshari.

  A vexing problem in mitochondrial medicine is our limited capacity to evaluate the extent of brain disease in vivo. This limitation has hindered our understanding of the mechanisms that underlie the imaging phenotype in the brain of patients with mitochondrial diseases and our capacity to identify new biomarkers and therapeutic targets. Using comprehensive imaging, we analyzed the metabolic network that drives the brain structural and metabolic features of a mouse model of pyruvate dehydrogenase deficiency (PDHD). As the disease progressed in this animal, in vivo brain glucose uptake and glycolysis increased. Propionate served as a major anaplerotic substrate, predominantly metabolized by glial cells. A combination of propionate and a ketogenic diet extended lifespan, improved neuropathology, and ameliorated motor deficits in these animals. Together, intermediary metabolism is quite distinct in the PDHD brain-it plays a key role in the imaging phenotype, and it may uncover new treatments for this condition.

Keywords:  brain; glucose; imaging; ketogenic diet; metabolism; propionate; pyruvate; pyruvate dehydrogenase deficiency

DOI:  https://doi.org/10.1016/j.cmet.2024.05.002
Cancer Res. 2024 Jun 04. 84(11): 1834-1855

Obesogenic High-Fat Diet and MYC Cooperate to Promote Lactate Accumulation and Tumor Microenvironment Remodeling in Prostate Cancer.

Nadia Boufaied, Paolo Chetta, Tarek Hallal, Stefano Cacciatore, Daniela Lalli, Carole Luthold, Kevin Homsy, Eddie L Imada, Sudeepa Syamala, Cornelia Photopoulos, Anna Di Matteo, Anna de Polo, Alessandra Maria Storaci, Ying Huang, Francesca Giunchi, Patricia A Sheridan, Gregory Michelotti, Quang-De Nguyen, Xin Zhao, Yang Liu, Elai Davicioni, Daniel E Spratt, Simone Sabbioneda, Giovanni Maga, Lorelei A Mucci, Claudia Ghigna, Luigi Marchionni, Lisa M Butler, Leigh Ellis, François Bordeleau, Massimo Loda, Valentina Vaira, David P Labbé, Giorgia Zadra.

Cancer cells exhibit metabolic plasticity to meet oncogene-driven dependencies while coping with nutrient availability. A better understanding of how systemic metabolism impacts the accumulation of metabolites that reprogram the tumor microenvironment (TME) and drive cancer could facilitate development of precision nutrition approaches. Using the Hi-MYC prostate cancer mouse model, we demonstrated that an obesogenic high-fat diet (HFD) rich in saturated fats accelerates the development of c-MYC-driven invasive prostate cancer through metabolic rewiring. Although c-MYC modulated key metabolic pathways, interaction with an obesogenic HFD was necessary to induce glycolysis and lactate accumulation in tumors. These metabolic changes were associated with augmented infiltration of CD206+ and PD-L1+ tumor-associated macrophages (TAM) and FOXP3+ regulatory T cells, as well as with the activation of transcriptional programs linked to disease progression and therapy resistance. Lactate itself also stimulated neoangiogenesis and prostate cancer cell migration, which were significantly reduced following treatment with the lactate dehydrogenase inhibitor FX11. In patients with prostate cancer, high saturated fat intake and increased body mass index were associated with tumor glycolytic features that promote the infiltration of M2-like TAMs. Finally, upregulation of lactate dehydrogenase, indicative of a lactagenic phenotype, was associated with a shorter time to biochemical recurrence in independent clinical cohorts. This work identifies cooperation between genetic drivers and systemic metabolism to hijack the TME and promote prostate cancer progression through oncometabolite accumulation. This sets the stage for the assessment of lactate as a prognostic biomarker and supports strategies of dietary intervention and direct lactagenesis blockade in treating advanced prostate cancer.
SIGNIFICANCE: Lactate accumulation driven by high-fat diet and MYC reprograms the tumor microenvironment and promotes prostate cancer progression, supporting the potential of lactate as a biomarker and therapeutic target in prostate cancer. See related commentary by Frigo, p. 1742.

DOI: https://doi.org/10.1158/0008-5472.CAN-23-0519
Redox Biol. 2024 May 30. pii: S2213-2317(24)00198-8. [Epub ahead of print]73 103220

A targetable PRR11-DHODH axis drives ferroptosis- and temozolomide-resistance in glioblastoma.

Zong Miao, Lei Xu, Wei Gu, Yimin Ren, Rong Li, Shuai Zhang, Chao Chen, Hongxiang Wang, Jing Ji, Juxiang Chen.

  Temozolomide (TMZ) is a widely utilized chemotherapy treatment for patients with glioblastoma (GBM), although drug resistance constitutes a major therapeutic hurdle. Emerging evidence suggests that ferroptosis-mediated therapy could offer an appropriate alternative treatment option against cancer cells that are resistant to certain drugs. However, recurrent gliomas display robust ferroptosis resistance, although the precise mechanism of resistance remains elusive. In the present work, we report that proline rich protein 11 (PRR11) depletion significantly sensitizes GBM cells to TMZ by inducing ferroptosis. Mechanistically, PRR11 directly binds to and stabilizes dihydroorotate dehydrogenase (DHODH), which leads to glioma ferroptosis-resistant in a DHODH-dependent manner in vivo and in vitro. Furthermore, PRR11 inhibits HERC4 and DHODH binding, by suppressing the recruitment of E3 ubiquitin ligase HERC4 and polyubiquitination degradation of DHODH at the K306 site, which maintains DHODH protein stability. Importantly, downregulated PRR11 increases lipid peroxidation and alters DHODH-mediated mitochondrial morphology, thereby promoting ferroptosis and increasing TMZ chemotherapy sensitivity. In conclusion, our results reveal a mechanism via which PRR11 drives ferroptosis resistance and identifies ferroptosis induction and TMZ as an attractive combined therapeutic strategy for GBM.

Keywords:  DHODH; Ferroptosis; Glioblastoma; HERC4; PRR11; Ubiquitination

DOI:  https://doi.org/10.1016/j.redox.2024.103220
Redox Biol. 2024 May 31. pii: S2213-2317(24)00190-3. [Epub ahead of print]73 103212

ROS-mediated cytoplasmic localization of CARM1 induces mitochondrial fission through DRP1 methylation.

Yena Cho, Yong Kee Kim.

  The dynamic regulation of mitochondria through fission and fusion is essential for maintaining cellular homeostasis. In this study, we discovered a role of coactivator-associated arginine methyltransferase 1 (CARM1) in mitochondrial dynamics. CARM1 methylates specific residues (R403 and R634) on dynamin-related protein 1 (DRP1). Methylated DRP1 interacts with mitochondrial fission factor (Mff) and forms self-assembly on the outer mitochondrial membrane, thereby triggering fission, reducing oxygen consumption, and increasing reactive oxygen species (ROS) production. This sets in motion a feedback loop that facilitates the translocation of CARM1 from the nucleus to the cytoplasm, enhancing DRP1 methylation and ROS production through mitochondrial fragmentation. Consequently, ROS reinforces the CARM1-DRP1-ROS axis, resulting in cellular senescence. Depletion of CARM1 or DRP1 impedes cellular senescence by reducing ROS accumulation. The uncovering of the above-described mechanism fills a missing piece in the vicious cycle of ROS-induced senescence and contributes to a better understanding of the aging process.

Keywords:  CARM1; DRP1; Methylation; Mitochondrial dynamics; ROS; Senescence

DOI:  https://doi.org/10.1016/j.redox.2024.103212
Breast Cancer Res. 2024 Jun 07. 26(1): 96

Hypoxia-mediated repression of pyruvate carboxylase drives immunosuppression.

Michael F Coleman, Eylem Kulkoyluoglu Cotul, Alexander J Pfeil, Emily N Devericks, Muhammad H Safdar, Marvis Monteiro, Hao Chen, Alyssa N Ho, Numair Attaar, Hannah M Malian, Violet A Kiesel, Alexis Ramos, Matthew Smith, Heena Panchal, Adam Mailloux, Dorothy Teegarden, Stephen D Hursting, Michael K Wendt.

BACKGROUND: Metabolic plasticity mediates breast cancer survival, growth, and immune evasion during metastasis. However, how tumor cell metabolism is influenced by and feeds back to regulate breast cancer progression are not fully understood. We identify hypoxia-mediated suppression of pyruvate carboxylase (PC), and subsequent induction of lactate production, as a metabolic regulator of immunosuppression.
METHODS: We used qPCR, immunoblot, and reporter assays to characterize repression of PC in hypoxic primary tumors. Steady state metabolomics were used to identify changes in metabolite pools upon PC depletion. In vivo tumor growth and metastasis assays were used to evaluate the impact of PC manipulation and pharmacologic inhibition of lactate transporters. Immunohistochemistry, flow cytometry, and global gene expression analyzes of tumor tissue were employed to characterize the impact of PC depletion on tumor immunity.
RESULTS: PC is essential for metastatic colonization of the lungs. In contrast, depletion of PC in tumor cells promotes primary tumor growth. This effect was only observed in immune competent animals, supporting the hypothesis that repression of PC can suppress anti-tumor immunity. Exploring key differences between the pulmonary and mammary environments, we demonstrate that hypoxia potently downregulated PC. In the absence of PC, tumor cells produce more lactate and undergo less oxidative phosphorylation. Inhibition of lactate metabolism was sufficient to restore T cell populations to PC-depleted mammary tumors.
CONCLUSIONS: We present a dimorphic role for PC in primary mammary tumors vs. pulmonary metastases. These findings highlight a key contextual role for PC-directed lactate production as a metabolic nexus connecting hypoxia and antitumor immunity.

DOI: https://doi.org/10.1186/s13058-024-01854-1
Aging (Albany NY). 2024 Jun 04. 16

Mitophagy and cancer: role of BNIP3/BNIP3L as energetic drivers of stemness features, ATP production, proliferation, and cell migration.

Marta Mauro-Lizcano, Federica Sotgia, Michael P Lisanti.

  Mitophagy is a selective form of autophagy which permits the removal of dysfunctional or excess mitochondria. This occurs as an adaptative response to physiological stressors, such as hypoxia, nutrient deprivation, or DNA damage. Mitophagy is promoted by specific mitochondrial outer membrane receptors, among which are BNIP3 and BNIP3L. The role of mitophagy in cancer is being widely studied, and more specifically in the maintenance of cancer stem cell (CSC) properties, such as self-renewal. Given that CSCs are responsible for treatment failure and metastatic capacity, targeting mitophagy could be an interesting approach for CSC elimination. Herein, we describe a new model system to enrich sub-populations of cancer cells with high basal levels of mitophagy, based on the functional transcriptional activity of BNIP3 and BNIP3L. Briefly, we employed a BNIP3(L)-promoter-eGFP-reporter system to isolate cancer cells with high BNIP3/BNIP3L transcriptional activity by flow cytometry (FACS). The model was validated by using complementary lysosomal and mitophagy-specific probes, as well as the mitochondrially-targeted red fluorescent protein (RFP), namely mt-Keima. High BNIP3/BNIP3L transcriptional activity was accompanied by increases in i) BNIP3/BNIP3L protein levels, ii) lysosomal mass, and iii) basal mitophagy activity. Furthermore, cancer cells with increased BNIP3/BNIP3L transcriptional activity exhibited CSC features, such as greater mammosphere-forming ability and high CD44 levels. To further explore the model, we also analysed other stemness characteristics in MCF7 and MDA-MB-231 breast cancer cell lines, directly demonstrating that BNIP3(L)-high cells were more metabolically active, proliferative, migratory, and drug-resistant, with elevated anti-oxidant capacity. Therefore, high levels of basal mitophagy appear to enhance CSC features.

Keywords:  BNIP3; BNIP3L(NIX); cancer stem cells (CSCs); flow cytometry (FACS); mitophagy

DOI:  https://doi.org/10.18632/aging.205939
bioRxiv. 2024 May 23. pii: 2024.05.21.595226. [Epub ahead of print]

Cardiolipin clustering promotes mitochondrial membrane dynamics.

Kelly E Zuccaro, Luciano A Abriata, Fernando Teixeira Pinto Meireles, Frank R Moss, Adam Frost, Matteo Dal Peraro, Halil Aydin.

Cardiolipin (CL) is a mitochondria-specific phospholipid that forms heterotypic interactions with membrane-shaping proteins and regulates the dynamic remodeling and function of mitochondria. However, the precise mechanisms through which CL influences mitochondrial morphology are not well understood. In this study, employing molecular dynamics (MD) simulations, we observed CL localize near the membrane-binding sites of the mitochondrial fusion protein Optic Atrophy 1 (OPA1). To validate these findings experimentally, we developed a bromine-labeled CL probe to enhance cryoEM contrast and characterize the structure of OPA1 assemblies bound to the CL-brominated lipid bilayers. Our images provide direct evidence of interactions between CL and two conserved motifs within the paddle domain (PD) of OPA1, which control membrane-shaping mechanisms. We further observed a decrease in membrane remodeling activity for OPA1 in lipid compositions with increasing concentrations of monolyso-cardiolipin (MLCL). Suggesting that the partial replacement of CL by MLCL accumulation, as observed in Barth syndrome-associated mutations of the tafazzin phospholipid transacylase, compromises the stability of protein-membrane interactions. Our analyses provide insights into how biological membranes regulate the mechanisms governing mitochondrial homeostasis.
Teaser: This study reveals how CL modulates the activity of OPA1 and how MLCL impacts its ability to govern mitochondrial function.

DOI: https://doi.org/10.1101/2024.05.21.595226
J Biol Chem. 2024 Jun 04. pii: S0021-9258(24)01949-5. [Epub ahead of print] 107448

The ubiquitin E3 ligase APC/CCdc20 mediates mitotic degradation of OGT.

Li Meng, Rui Dong, Weixiao Mi, Ke Qin, Kunfu Ouyang, Jianwei Sun, Jing Li.

  O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (OGT) is the sole enzyme that catalyzes all O-GlcNAcylation reactions intracellularly. Previous investigations have found that OGT levels oscillate during the cell division process. Specifically, OGT abundance is downregulated during mitosis, but the underlying mechanism is lacking. Here we demonstrate that OGT is ubiquitinated by the ubiquitin E3 ligase, anaphase promoting complex/cyclosome (APC/C)-cell division cycle 20 (Cdc20). We show that APC/CCdc20 interacts with OGT through a conserved destruction box (D-box): Arg-351/Leu-354, the abrogation of which stabilizes OGT. As APC/CCdc20-substrate binding is often preceded by a priming ubiquitination event, we also used mass spectrometry and mapped OGT Lys-352 to be a ubiquitination site, which is a prerequisite for OGT association with APC/C subunits. Interestingly in The Cancer Genome Atlas, R351C is a uterine carcinoma mutant, suggesting that mutations of the D-box are linked with tumorigenesis. Paradoxically, we found that both R351C and the D-box mutants (R351A/L354A) inhibit uterine carcinoma in mouse xenograft models, probably due to impaired cell division and proliferation. In sum, we propose a model where OGT Lys-352 ubiquitination primes its binding with APC/C, and then APC/CCdc20 partners with OGT through the D-box for its mitotic destruction. Our work not only highlights the key mechanism that regulates OGT during the cell cycle, but also reveals the mutual coordination between glycosylation and the cell division machinery.

Keywords:  APC/C(Cdc20); OGT; cell cycle; ubiquitination; uterine carcinoma

DOI:  https://doi.org/10.1016/j.jbc.2024.107448
J Biol Chem. 2024 May 30. pii: S0021-9258(24)01927-6. [Epub ahead of print] 107426

Circular RNA circMYLK4 shifts energy metabolism from glycolysis to OXPHOS by binding to the calcium channel auxiliary subunit CACNA2D2.

Haigang Cao, Chenchen Li, Xiaohui Sun, Jinjin Yang, Xiao Li, Gongshe Yang, Jianjun Jin, Xine Shi.

  Skeletal muscle is heterogeneous tissue, composed of fast-twitch fibers primarily relying on glycolysis and slow-twitch fibers primarily relying on oxidative phosphorylation (OXPHOS). The relative expression and balance of glycolysis and oxidative phosphorylation in skeletal muscle are crucial for muscle growth and skeletal muscle metabolism. Here, we employed multi-omics approaches including transcriptomics, proteomics, phosphoproteomics, and metabolomics to unravel the role of circMYLK4, a differentially expressed circRNA in fast and slow-twitch muscle fibers, in muscle fiber metabolism. We discovered that circMYLK4 inhibits glycolysis and promotes mitochondrial oxidative phosphorylation. Mechanistically, circMYLK4 interacts with the voltage-gated calcium channel auxiliary subunit CACNA2D2, leading to the inhibition of Ca2+ release from the sarcoplasmic reticulum. The decrease in cytoplasmic Ca2+ concentration inhibits the expression of key enzymes, PHKB and PHKG1, involved in glycogen breakdown, thereby suppressing glycolysis. On the other hand, the increased fatty acid β-oxidation enhances the tricarboxylic acid (TCA) cycle and mitochondrial oxidative phosphorylation. In general, circMYLK4 plays an indispensable role in maintaining the metabolic homeostasis of skeletal muscle.

Keywords:  calcium; circRNA; energy metabolism; fatty acid oxidation; glycolysis; skeletal muscle

DOI:  https://doi.org/10.1016/j.jbc.2024.107426
J Exp Clin Cancer Res. 2024 Jun 03. 43(1): 158

Extracellular vesicles activated cancer-associated fibroblasts promote lung cancer metastasis through mitophagy and mtDNA transfer.

Zhuan Zhou, Chunhui Qu, Peijun Zhou, Qin Zhou, Dan Li, Xia Wu, Lifang Yang.

   BACKGROUND: Studies have shown that oxidative stress and its resistance plays important roles in the process of tumor metastasis, and mitochondrial dysfunction caused by mitochondrial DNA (mtDNA) damage is an important molecular event in oxidative stress. In lung cancer, the normal fibroblasts (NFs) are activated as cancer-associated fibroblasts (CAFs), and act in the realms of the tumor microenvironment (TME) with consequences for tumor growth and metastasis. However, its activation mechanism and whether it participates in tumor metastasis through antioxidative stress remain unclear.
METHODS: The role and signaling pathways of tumor cell derived extracellular vesicles (EVs) activating NFs and the characteristic of induced CAFs (iCAFs) were measured by the transmission electron microscopy, nanoparticle tracking analysis, immunofluorescence, collagen contraction assay, quantitative PCR, immunoblotting, luciferase reporter assay and mitochondrial membrane potential detection. Mitochondrial genome and single nucleotide polymorphism sequencing were used to investigate the transport of mtDNA from iCAFs to ρ0 cells, which were tumor cells with mitochondrial dysfunction caused by depletion of mtDNA. Further, the effects of iCAFs on mitochondrial function, growth and metastasis of tumor cells were analysed in co-culture models both in vitro and in vivo, using succinate dehydrogenase, glutathione and oxygen consumption rate measurements, CCK-8 assay, transwell assay, xenotransplantation and metastasis experiments as well as in situ hybridization and immunohistochemistry.
RESULTS: Our findings revealed that EVs derived from high-metastatic lung cancer cells packaged miR-1290 that directly targets MT1G, leading to activation of AKT signaling in NFs and inducing NFs conversion to CAFs. The iCAFs exhibit higher levels of autophagy and mitophagy and more mtDNA release, and reactive oxygen species (ROS) could further promote this process. After cocultured with the conditioned medium (CM) of iCAFs, the ρ0 cells may restore its mitochondrial function by acquisition of mtDNA from CAFs, and further promotes tumor metastasis.
CONCLUSIONS: These results elucidate a novel mechanism that CAFs activated by tumor-derived EVs can promote metastasis by transferring mtDNA and restoring mitochondrial function of tumor cells which result in resistance of oxidative stress, and provide a new therapeutic target for lung cancer metastasis.

Keywords:  Cancer-associated fibroblasts; Extracellular vesicles; Lung cancer; Metastasis; Mitophagy; mtDNA

DOI:  https://doi.org/10.1186/s13046-024-03077-w
Proc Natl Acad Sci U S A. 2024 Jun 11. 121(24): e2404668121

Cu(II) complex that synergistically potentiates cytotoxicity and an antitumor immune response by targeting cellular redox homeostasis.

Ke-Bin Huang, Feng-Yang Wang, Yuan Lu, Liang-Mei Yang, Nian Long, Shan-Shan Wang, Zhiying Xie, Matthew Levine, Taotao Zou, Jonathan L Sessler, Hong Liang.

  Developing anticancer drugs with low side effects is an ongoing challenge. Immunogenic cell death (ICD) has received extensive attention as a potential synergistic modality for cancer immunotherapy. However, only a limited set of drugs or treatment modalities can trigger an ICD response and none of them have cytotoxic selectivity. This provides an incentive to explore strategies that might provide more effective ICD inducers free of adverse side effects. Here, we report a metal-based complex (Cu-1) that disrupts cellular redox homeostasis and effectively stimulates an antitumor immune response with high cytotoxic specificity. Upon entering tumor cells, this Cu(II) complex enhances the production of intracellular radical oxidative species while concurrently depleting glutathione (GSH). As the result of heightening cellular oxidative stress, Cu-1 gives rise to a relatively high cytotoxicity to cancer cells, whereas normal cells with low levels of GSH are relatively unaffected. The present Cu(II) complex initiates a potent ferroptosis-dependent ICD response and effectively inhibits in vivo tumor growth in an animal model (c57BL/6 mice challenged with colorectal cancer). This study presents a strategy to develop metal-based drugs that could synergistically potentiate cytotoxic selectivity and promote apoptosis-independent ICD responses through perturbations in redox homeostasis.

Keywords:  disrupting redox homeostasis; ferroptosis; immunogenic cell death; metal complex

DOI:  https://doi.org/10.1073/pnas.2404668121
Sci Transl Med. 2024 Jun 05. 16(750): eadk7640

Comparative analysis of Bcl-2 family protein overexpression in CAR T cells alone and in combination with BH3 mimetics.

Felix Korell, Michael L Olson, Diego Salas-Benito, Mark B Leick, Rebecca C Larson, Amanda Bouffard, Harrison Silva, Alessandro Gasparetto, Trisha R Berger, Michael C Kann, Markus Mergen, Tamina Kienka, Marc Wehrli, Nicholas J Haradhvala, Stefanie R Bailey, Anthony Letai, Marcela V Maus.

Approximately 50% of patients with hematologic malignancies relapse after chimeric antigen receptor (CAR) T cell treatment; mechanisms of failure include loss of CAR T persistence and tumor resistance to apoptosis. We hypothesized that both of these challenges could potentially be overcome by overexpressing one or more of the Bcl-2 family proteins in CAR T cells to reduce their susceptibility to apoptosis, both alone and in the presence of BH3 mimetics, which can be used to activate apoptotic machinery in malignant cells. We comprehensively investigated overexpression of different Bcl-2 family proteins in CAR T cells with different signaling domains as well as in different tumor types. We found that Bcl-xL and Bcl-2 overexpression in CAR T cells bearing a 4-1BB costimulatory domain resulted in increased expansion and antitumor activity, reduced exhaustion, and decreased apoptotic priming. In addition, CAR T cells expressing either Bcl-xL or a venetoclax-resistant Bcl-2 variant led to enhanced antitumor efficacy and survival in murine xenograft models of lymphoma and leukemia in the presence or absence of the BH3 mimetic venetoclax, a clinically approved BH3 mimetic. In this setting, Bcl-xL overexpression had stronger effects than overexpression of Bcl-2 or the Bcl-2(G101V) variant. These findings suggest that CAR T cells could be optimally engineered by overexpressing Bcl-xL to enhance their persistence while opening a therapeutic window for combination with BH3 mimetics to prime tumors for apoptosis.

DOI: https://doi.org/10.1126/scitranslmed.adk7640
J Cell Mol Med. 2024 Jun;28(11): e18406

Metabolic reprogramming-driven homologous recombination and TCA cycle dysregulation contribute to poor prognoses in lung adenocarcinoma.

Zhanyu Xu, Dongming He, Liuliu Huang, Kun Deng, Wei Jiang, Junqi Qin, Zhiwen Zheng, Tiaozhan Zheng, Shikang Li.

  Increasing evidence has shown that homologous recombination (HR) and metabolic reprogramming are essential for cellular homeostasis. These two processes are independent as well as closely intertwined. Nevertheless, they have rarely been reported in lung adenocarcinoma (LUAD). We analysed the genomic, immune microenvironment and metabolic microenvironment features under different HR activity states. Using cell cycle, EDU and cell invasion assays, we determined the impacts of si-SHFM1 on the LUAD cell cycle, proliferation and invasion. The levels of isocitrate dehydrogenase (IDH) and α-ketoglutarate dehydrogenase (α-KGDH) were determined by ELISA in the NC and si-SHFM1 groups of A549 cells. Finally, cell samples were used to extract metabolites for HPIC-MS/MS to analyse central carbon metabolism. We found that high HR activity was associated with a poor prognosis in LUAD, and HR was an independent prognostic factor for TCGA-LUAD patients. Moreover, LUAD samples with a high HR activity presented low immune infiltration levels, a high degree of genomic instability, a good response status to immune checkpoint blockade therapy and a high degree of drug sensitivity. The si-SHFM1 group presented a significantly higher proportion of cells in the G0/G1 phase, lower levels of DNA replication, and significantly lower levels of cell migration and both TCA enzymes. Our current results indicated that there is a strong correlation between HR and the TCA cycle in LUAD. The TCA cycle can promote SHFM1-mediated HR in LUAD, raising their activities, which can finally result in a poor prognosis and impair immunotherapeutic efficacy.

Keywords:  SHFM1; homologous recombination; lung adenocarcinoma; metabolic reprogramming; tricarboxylic acid cycle

DOI:  https://doi.org/10.1111/jcmm.18406
Technol Cancer Res Treat. 2024 Jan-Dec;23:23 15330338241258570

A Comprehensive Prognostic Model for Colon Adenocarcinoma Depending on Nuclear-Mitochondrial-Related Genes.

Lingling Lv, Yuqing Huang, Qiong Li, Yuan Wu, Lan Zheng.

  Background: Colon adenocarcinoma (COAD) has increasing incidence and is one of the most common malignant tumors. The mitochondria involved in cell energy metabolism, oxygen free radical generation, and cell apoptosis play important roles in tumorigenesis and progression. The relationship between mitochondrial genes and COAD remains largely unknown. Methods: COAD data including 512 samples were set out from the UCSC Xena database. The nuclear mitochondrial-related genes (NMRGs)-related risk prognostic model and prognostic nomogram were constructed, and NMRGs-related gene mutation and the immune environment were analyzed using bioinformatics methods. Then, a liver metastasis model of colorectal cancer was constructed and protein expression was detected using Western blot assay. Results: A prognostic model for COAD was constructed. Comparing the prognostic model dataset and the validation dataset showed considerable correlation in both risk grouping and prognosis. Based on the risk score (RS) model, the samples of the prognostic dataset were divided into high risk group and low risk group. Moreover, pathologic N and T stage and tumor recurrence in the two risk groups were significantly different. The four prognostic factors, including age and pathologic T stage in the nomogram survival model also showed excellent predictive performance. An optimal combination of nine differentially expressed NMRGs was finally obtained, including LARS2, PARS2, ETHE1, LRPPRC, TMEM70, AARS2, ACAD9, VARS2, and ATP8A2. The high-RS group had more inflamed immune features, including T and CD4+ memory cell activation. Besides, mitochondria-associated LRPPRC and LARS2 expression levels were increased in vivo xenograft construction and liver metastases assays. Conclusion: This study established a comprehensive prognostic model for COAD, incorporating nine genes associated with nuclear-mitochondrial functions. This model demonstrates superior predictive performance across four prognostic factors: age, pathological T stage, tumor recurrence, and overall prognosis. It is anticipated to be an effective model for enhancing the prognosis and treatment of COAD.

Keywords:  colon adenocarcinoma; nuclear mitochondrial-related genes; risk prognostic model

DOI:  https://doi.org/10.1177/15330338241258570
Biochem Biophys Res Commun. 2024 May 29. pii: S0006-291X(24)00714-9. [Epub ahead of print]723 150178

SLC7A11-mediated cystine import protects against NDUFS7 deficiency-induced cell death in HEK293T cells.

Jieli Chen, Liuze Gao.

  Cell models of mitochondrial complex Ⅰ (CⅠ) deficiency display significant elevations in reactive oxygen species (ROS) levels and an increase in cellular apoptosis. However, the underlying mechanisms governing anti-apoptotic processes in CⅠ-deficient cells remain elusive. Here, we introduced a mutation in NDUFS7, a crucial subunit of CI, in HEK293T cells and found that the absence of NDUFS7 resulted in reduced cell proliferation, elevated cell death, and increased susceptibility to oxidative stress. Mechanismly, we revealed that the upregulation of SLC7A11 played a crucial role in mitigating cell death resulting from NDUFS7 deficiency. Specifically, the increased expression of SLC7A11 enhanced cystine import, which subsequently reduced cell death by promoting the biosynthesis of reduced glutathione (GSH). Collectively, our findings suggest that SLC7A11-mediated cystine import, representing a novel pathway independent of NADPH production, plays a vital role in protection against NDUFS7 deficiency-induced cell death. This novel pathway provides potential insights into the understanding of pathogenic mechanisms and the therapeutic management of mitochondrial disorders associated with CⅠ deficiency.

Keywords:  Cell death; Cystine; Deficiency; NDUFS7; SLC7A11

DOI:  https://doi.org/10.1016/j.bbrc.2024.150178