bims-mibica 2024-09-22 papers

bims-mibica

Biomed News

on Mitochondrial bioenergetics in cancer

Issue of 2024–09–22
twenty-two papers selected by
Kelsey Fisher-Wellman, Wake Forest University

Mitochondrial dynamics as a potential therapeutic target in acute myeloid leukemia.
mLumiOpto is a Mitochondrial-Targeted Gene Therapy for Treating Cancer.
Intercellular nanotube-mediated mitochondrial transfer enhances T cell metabolic fitness and antitumor efficacy.
TBK1 adaptor AZI2/NAP1 regulates NDP52-driven mitochondrial autophagy.
Understanding the Warburg Effect in Cancer.
Technologies for Decoding Cancer Metabolism with Spatial Resolution.
Macroautophagy/autophagy promotes resistance to KRASG12D-targeted therapy through glutathione synthesis.
Cancer Metabolism: Aspirations for the Coming Decade.
PARP-1 negatively regulates nucleolar protein pool and mitochondrial activity: a cell protective mechanism.
Characteristics of Oxidative Phosphorylation-Related Subtypes and Construction of a Prognostic Signature in Ovarian Cancer.
IF1 is a cold-regulated switch of ATP synthase hydrolytic activity to support thermogenesis in brown fat.
Potent combination benefit of the AKT inhibitor capivasertib and the BCL-2 inhibitor venetoclax in diffuse large B cell lymphoma.
Metabolic ripple effects - deciphering how lipid metabolism in cancer interfaces with the tumor microenvironment.
Metabolism of primary high-grade serous ovarian carcinoma (HGSOC) cells under limited glutamine or glucose availability.
Lipolysis-stimulated lipoprotein receptor promote lipid uptake and fatty acid oxidation in gastric cancer.
Quantitative proteomics of patient fibroblasts reveal biomarkers and diagnostic signatures of mitochondrial disease.
Ablating the glutaredoxin-2 (Glrx2) gene protects male mice against non-alcoholic fatty liver disease (NAFLD) by limiting oxidative distress.
Clinical efficacy and immune response of BCL-2 inhibitors combined with hypomethylating agents in the treatment of acute myeloid leukemia.
Obesity facilitated colon cancer progression is mediated by increased diacylglycerol o-acyltransferases 1 and 2 (DGAT1/2) levels.
Exploiting branched-chain amino acid metabolism and NOTCH3 expression to predict and target colorectal cancer progression.
Bone Marrow Stromal Cells Enhance Differentiation of Acute Myeloid Leukemia Induced by Pyrimidine Synthesis Inhibitors.
Oncogenic Mutant p53 Sensitizes Non-Small Cell Lung Cancer Cells to Proteasome Inhibition via Oxidative Stress-Dependent Induction of Mitochondrial Apoptosis.

Int J Hematol. 2024 Sep 16.

Mitochondrial dynamics as a potential therapeutic target in acute myeloid leukemia.

Mariko Kinoshita, Yusuke Saito, Kento Otani, Yuya Uehara, Shun Nagasawa, Midori Nakagawa, Ai Yamada, Sachiyo Kamimura, Hiroshi Moritake.

  Acute myeloid leukemia (AML) cells are highly dependent on oxidative phosphorylation and the mitochondrial dynamics regulated by fusion-related genes MFN1, MFN2, and OPA1 and fission-related genes DNM1L and MFF. An analysis of previously published gene expression datasets showed that high expression of MFF was significantly associated with poor prognosis in patients with AML. Based on this finding, we investigated the impact of mitochondrial dynamics in AML. Transduction of shRNA against fission-related genes, DNM1L and MFF, inhibited growth and increased the mitochondrial area in AML cell lines. Extracellular flux analysis showed that deletion of mitochondrial dynamic regulators reduced mitochondrial respiration without significantly affecting glycolysis, except in shDNM1L-transfected cells. Immunodeficient NOG mice transplanted with DNM1L- or MFF-knockdown AML cells survived significantly longer than controls. Treatment of AML cell lines with Mdivi-1, which inhibits the DRP1 encoded by DNM1L, inhibited cell proliferation and oxidative phosphorylation. Our results show that mitochondrial dynamics play an important role in AML, and provide novel biological insights. The inhibition of mitochondrial dynamics induces unique mitochondrial alterations, which may be explored as a potential therapeutic target in AML.

Keywords:  AML; DNM1L; MFF; Mdivi-1; Mitochondrial dynamics

DOI:  https://doi.org/10.1007/s12185-024-03843-8
Cancer Res. 2024 Sep 17.

mLumiOpto is a Mitochondrial-Targeted Gene Therapy for Treating Cancer.

Kai Chen, Patrick Ernst, Anusua Sarkar, Seulhee Kim, Yingnan Si, Tanvi Varadkar, Matthew D Ringel, Xiaoguang Liu, Lufang Zhou.

Mitochondria are important in various aspects of cancer development and progression. Targeting mitochondria in cancer cells holds great therapeutic promise, yet current strategies to specifically and effectively destroy cancer mitochondria in vivo are limited. Here, we developed mLumiOpto, an innovative mitochondrial-targeted luminoptogenetics gene therapy designed to directly disrupt the inner mitochondrial membrane (IMM) potential and induce cancer cell death. The therapeutic approach included synthesis of a blue light-gated cationic channelrhodopsin (CoChR) in the IMM and co-expression of a blue bioluminescence-emitting nanoluciferase (NLuc) in the cytosol of the same cells. The mLumiOpto genes were selectively delivered to cancer cells in vivo by an adeno-associated virus (AAV) carrying a cancer-specific promoter or cancer-targeted monoclonal antibody-tagged exosome-associated AAV (mAb-Exo-AAV). Induction with NLuc luciferin elicited robust endogenous bioluminescence, which activated CoChR, triggering cancer cell mitochondrial depolarization and subsequent cell death. Importantly, mLumiOpto demonstrated remarkable efficacy in reducing tumor burden and killing tumor cells in glioblastoma and triple-negative breast cancer xenograft mouse models. Furthermore, the approach induced an anti-tumor immune response, increasing infiltration of dendritic cells and CD8+ T cells in the tumor microenvironment. These findings establish mLumiOpto as a promising therapeutic strategy by targeting cancer cell mitochondria in vivo.

DOI: https://doi.org/10.1158/0008-5472.CAN-24-0984
Cell. 2024 Sep 12. pii: S0092-8674(24)00956-5. [Epub ahead of print]

Intercellular nanotube-mediated mitochondrial transfer enhances T cell metabolic fitness and antitumor efficacy.

Jeremy G Baldwin, Christoph Heuser-Loy, Tanmoy Saha, Roland C Schelker, Dragana Slavkovic-Lukic, Nicholas Strieder, Inmaculada Hernandez-Lopez, Nisha Rana, Markus Barden, Fabio Mastrogiovanni, Azucena Martín-Santos, Andrea Raimondi, Philip Brohawn, Brandon W Higgs, Claudia Gebhard, Veena Kapoor, William G Telford, Sanjivan Gautam, Maria Xydia, Philipp Beckhove, Sina Frischholz, Kilian Schober, Zacharias Kontarakis, Jacob E Corn, Matteo Iannacone, Donato Inverso, Michael Rehli, Jessica Fioravanti, Shiladitya Sengupta, Luca Gattinoni.

  Mitochondrial loss and dysfunction drive T cell exhaustion, representing major barriers to successful T cell-based immunotherapies. Here, we describe an innovative platform to supply exogenous mitochondria to T cells, overcoming these limitations. We found that bone marrow stromal cells establish nanotubular connections with T cells and leverage these intercellular highways to transplant stromal cell mitochondria into CD8+ T cells. Optimal mitochondrial transfer required Talin 2 on both donor and recipient cells. CD8+ T cells with donated mitochondria displayed enhanced mitochondrial respiration and spare respiratory capacity. When transferred into tumor-bearing hosts, these supercharged T cells expanded more robustly, infiltrated the tumor more efficiently, and exhibited fewer signs of exhaustion compared with T cells that did not take up mitochondria. As a result, mitochondria-boosted CD8+ T cells mediated superior antitumor responses, prolonging animal survival. These findings establish intercellular mitochondrial transfer as a prototype of organelle medicine, opening avenues to next-generation cell therapies.

Keywords:  CAR T therapy; CD8(+) T cells; TCR-T therapy; TIL therapy; Talin 2; bone marrow stromal cells; cancer immunotherapy; immune metabolism; mitochondrial transfer; nanotubes

DOI:  https://doi.org/10.1016/j.cell.2024.08.029
J Biol Chem. 2024 Sep 12. pii: S0021-9258(24)02276-2. [Epub ahead of print] 107775

TBK1 adaptor AZI2/NAP1 regulates NDP52-driven mitochondrial autophagy.

Ryu Endo, Hiroki Kinefuchi, Momoha Sawada, Reika Kikuchi, Waka Kojima, Noriyuki Matsuda, Koji Yamano.

  Damaged mitochondria are selectively eliminated in a process called mitophagy. PINK1 and Parkin amplify ubiquitin signals on damaged mitochondria, which are then recognized by autophagy adaptors to induce local autophagosome formation. NDP52 and OPTN, two essential mitophagy adaptors, facilitate de novo synthesis of pre-autophagosomal membranes near damaged mitochondria by linking ubiquitinated mitochondria and ATG8 family proteins and by recruiting core autophagy initiation components. The multifunctional serine/threonine kinase TBK1 also plays important roles in mitophagy. OPTN directly binds TBK1 to form a positive feedback loop for isolation membrane expansion. TBK1 is also thought to indirectly interact with NDP52; however, its role in NDP52-driven mitophagy remains largely unknown. Here, we focused on two TBK1 adaptors, AZI2/NAP1 and TBKBP1/SINTBAD, that are thought to mediate the TBK1-NDP52 interaction. We found that both AZI2 and TBKBP1 are recruited to damaged mitochondria during Parkin-mediated mitophagy. Further, a series of AZI2 and TBKBP1 knockout constructs combined with an OPTN knockout showed that AZI2, but not TBKBP1, impacts NDP52-driven mitophagy. In addition, we found that AZI2 at S318 is phosphorylated during mitophagy, the impairment of which slightly inhibits mitochondrial degradation. These results suggest that AZI2, in concert with TBK1, plays an important role in NDP52-driven mitophagy.

Keywords:  autophagy; mitochondria; mitophagy; polyubiquitin chain; serine/threonine protein kinase

DOI:  https://doi.org/10.1016/j.jbc.2024.107775
Cold Spring Harb Perspect Med. 2024 Sep 16. pii: a041532. [Epub ahead of print]

Understanding the Warburg Effect in Cancer.

Zhaoqi Li, Muhammad Bin Munim, Daniel A Sharygin, Brooke J Bevis, Matthew G Vander Heiden.

Rapidly proliferating cells, including cancer cells, adapt metabolism to meet the increased energetic and biosynthetic demands of cell growth and division. Many rapidly proliferating cells exhibit increased glucose consumption and fermentation regardless of oxygen availability, a phenotype termed aerobic glycolysis or the Warburg effect in cancer. Several explanations for why cells engage in aerobic glycolysis and how it supports proliferation have been proposed, but none can fully explain all conditions and data where aerobic glycolysis is observed. Nevertheless, there is convincing evidence that the Warburg effect is important for the proliferation of many cancers, and that inhibiting either glucose uptake or fermentation can impair tumor growth. Here, we discuss what is known about metabolism associated with aerobic glycolysis and the evidence supporting various explanations for why aerobic glycolysis may be important in cancer and other contexts.

DOI: https://doi.org/10.1101/cshperspect.a041532
Cold Spring Harb Perspect Med. 2024 Sep 16. pii: a041553. [Epub ahead of print]

Technologies for Decoding Cancer Metabolism with Spatial Resolution.

Walter W Chen, Michael E Pacold, David M Sabatini, Naama Kanarek.

It is increasingly appreciated that cancer cells adapt their metabolic pathways to support rapid growth and proliferation as well as survival, often even under the poor nutrient conditions that characterize some tumors. Cancer cells can also rewire their metabolism to circumvent chemotherapeutics that inhibit core metabolic pathways, such as nucleotide synthesis. A critical approach to the study of cancer metabolism is metabolite profiling (metabolomics), the set of technologies, usually based on mass spectrometry, that allow for the detection and quantification of metabolites in cancer cells and their environments. Metabolomics is a burgeoning field, driven by technological innovations in mass spectrometers, as well as novel approaches to isolate cells, subcellular compartments, and rare fluids, such as the interstitial fluid of tumors. Here, we discuss three emerging metabolomic technologies: spatial metabolomics, single-cell metabolomics, and organellar metabolomics. The use of these technologies along with more established profiling methods, like single-cell transcriptomics and proteomics, is likely to underlie new discoveries and questions in cancer research.

DOI: https://doi.org/10.1101/cshperspect.a041553
Cancer Lett. 2024 Sep 12. pii: S0304-3835(24)00653-0. [Epub ahead of print]604 217258

Macroautophagy/autophagy promotes resistance to KRASG12D-targeted therapy through glutathione synthesis.

Leng Han, Lingjun Meng, Jiao Liu, Yangchun Xie, Rui Kang, Daniel J Klionsky, Daolin Tang, Yuanyuan Jia, Enyong Dai.

  KRASG12D mutation-driven pancreatic ductal adenocarcinoma (PDAC) represents a major challenge in medicine due to late diagnosis and treatment resistance. Here, we report that macroautophagy (hereafter autophagy), a cellular degradation and recycling process, contributes to acquired resistance against novel KRASG12D-targeted therapy. The KRASG12D protein inhibitor MRTX1133 induces autophagy in KRASG12D-mutated PDAC cells by blocking MTOR activity, and increased autophagic flux prevents apoptosis. Mechanistically, autophagy facilitates the generation of glutamic acid, cysteine, and glycine for glutathione synthesis. Increased glutathione levels reduce reactive oxygen species production, which impedes CYCS translocation from mitochondria to the cytosol, ultimately preventing the formation of the APAF1 apoptosome. Consequently, genetic interventions (utilizing ATG5 or BECN1 knockout) or pharmacological inhibition of autophagy (with chloroquine, bafilomycin A1, or spautin-1) enhance the anticancer activity of MRTX1133 in vitro and in various animal models (subcutaneous, patient-derived xenograft, and orthotopic). Moreover, the release of histones by apoptotic cells triggers an adaptive immune response when combining an autophagy inhibitor with MRTX1133 in immunocompetent mice. These findings establish a new strategy to overcome KRASG12D-targeted therapy resistance by inhibiting autophagy-dependent glutathione synthesis.

Keywords:  Autophagy; Drug resistance; Glutathione; KRAS mutation; Pancreatic cancer

DOI:  https://doi.org/10.1016/j.canlet.2024.217258
Cold Spring Harb Perspect Med. 2024 Sep 16. pii: a041555. [Epub ahead of print]

Cancer Metabolism: Aspirations for the Coming Decade.

Ralph J DeBerardinis, Karen H Vousden, Navdeep S Chandel.

Fueled by technological and conceptual advancements over the past two decades, research in cancer metabolism has begun to answer questions dating back to the time of Otto Warburg. But, as with most fields, new discoveries lead to new questions. This review outlines the emerging challenges that we predict will drive the next few decades of cancer metabolism research. These include developing a more realistic understanding of how metabolic activities are compartmentalized within cells, tissues, and organs; how metabolic preferences in tumors evolve during cancer progression from nascent, premalignant lesions to advanced, metastatic disease; and, most importantly, how we can best translate basic observations from preclinical models into novel therapies that benefit patients with cancer. With modern tools and an incredible amount of talent focusing on these problems, the upcoming decades should bring transformative discoveries.

DOI: https://doi.org/10.1101/cshperspect.a041555
Genes Environ. 2024 Sep 18. 46(1): 18

PARP-1 negatively regulates nucleolar protein pool and mitochondrial activity: a cell protective mechanism.

Atanu Ghorai, Soumajit Saha, Basuthkar J Rao.

   BACKGROUND: Poly(ADP-ribose) polymerase-1 (PARP-1) is a pan nuclear protein that utilizes NAD+ as a substrate for poly(ADP-ribosyl)ation reaction (PARylation), resulting in both auto-modification and the modification of its accepter proteins. Earlier reports suggested that several nucleolar proteins interact and colocalize with PARP-1, leading to their PARylation. However, whether PARP-1 has any role in nucleolar biogenesis and the functional relevance of such a role is still obscure.
RESULTS: Using PARP-1 depleted cells, we investigated the function of PARP-1 in maintaining the nucleolar morphology and protein levels under normal physiological conditions. Our results revealed that several nucleolar proteins like nucleolin, fibrillarin, and nucleophosmin get up-regulated when PARP-1 is depleted. Additionally, in line with the higher accumulation of nucleolin, stably depleted PARP-1 cells show lower activation of caspase-3, lesser annexin-V staining, and reduced accumulation of AIF in the nucleus upon induction of oxidative stress. Concurrently, PARP-1 silenced cells showed higher mitochondrial oxidative phosphorylation and more fragmented and intermediate mitochondria than the parental counterpart, suggesting higher metabolic activity for better survival.
CONCLUSION: Based on our findings, we demonstrate that PARP-1 may have a role in regulating nucleolar protein levels and mitochondrial activity, thus maintaining the homeostasis between cell protective and cell death pathways, and such cell-protective mechanism could be implicated as the priming state of a pre-cancerous condition or tumour dormancy.

Keywords:  Mitochondria; Nucleolin; Nucleolus; OXPHOS; Oxidative damage; PARP-1

DOI:  https://doi.org/10.1186/s41021-024-00312-w
Curr Gene Ther. 2024 Sep 16.

Characteristics of Oxidative Phosphorylation-Related Subtypes and Construction of a Prognostic Signature in Ovarian Cancer.

Jiaojiao Lu, Shuai Zhen, Xu Li.

   BACKGROUND: Ovarian cancer is associated with a high mortality rate. Oxidative Phosphorylation (OXPHOS) is an active metabolic pathway in cancer; nevertheless, its role in ovarian cancer continues to be ambiguous. Therefore, the objective of this study was to identify the prognostic value of OXPHOS-related genes and the immune landscape in ovarian cancer.
METHODS: We obtained public ovarian cancer-related datasets from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases and recognized OXPHOS-related genes from the GeneCards database and literature. Cox regression analyses were conducted to identify prognostic OXPHOS-related genes and develop a prognostic nomogram based on the OXPHOS score and clinicopathological features of patients. Functional enrichment analyses were employed to identify related processes.
RESULTS: A 12-gene signature was identified to classify the ovarian cancer patients into high- and low-risk groups. The Immunophenoscore (IPS) was higher in the OXPHOS score-high group than in the OXPHOS score-low group, suggesting a better response to immune checkpoint inhibitors. Functional enrichment analyses unveiled that OXPHOS-related genes were considerably abundant in a series of immune processes. The calibration curves of the constructed prognostic nomograms at 1, 2, and 3 years exhibited strong concordance between the anticipated and observed survival probabilities of ovarian cancer patients.
CONCLUSION: We have constructed a prognostic model containing 12 OXPHOS-related genes and demonstrated its strong predictive value in ovarian cancer patients. OXPHOS has been found to be closely linked to immune infiltration and the reaction to immunotherapy, which may contribute to improving individualized treatment and prognostic evaluation in ovarian cancer.

Keywords:  Ovarian cancer; The cancer genome atlas; immune infiltration.; overall survival; oxidative phosphorylation-related gene; prognosis

DOI:  https://doi.org/10.2174/0115665232323373240905104033
EMBO J. 2024 Sep 16.

IF1 is a cold-regulated switch of ATP synthase hydrolytic activity to support thermogenesis in brown fat.

Henver S Brunetta, Anna S Jung, Fernando Valdivieso-Rivera, Stepheny C de Campos Zani, Joel Guerra, Vanessa O Furino, Annelise Francisco, Marcelo Berçot, Pedro M Moraes-Vieira, Susanne Keipert, Martin Jastroch, Laurent O Martinez, Carlos H Sponton, Roger F Castilho, Marcelo A Mori, Alexander Bartelt.

  While mechanisms controlling uncoupling protein-1 (UCP1) in thermogenic adipocytes play a pivotal role in non-shivering thermogenesis, it remains unclear whether F1Fo-ATP synthase function is also regulated in brown adipose tissue (BAT). Here, we show that inhibitory factor 1 (IF1, encoded by Atp5if1), an inhibitor of ATP synthase hydrolytic activity, is a critical negative regulator of brown adipocyte energy metabolism. In vivo, IF1 levels are diminished in BAT of cold-adapted mice compared to controls. Additionally, the capacity of ATP synthase to generate mitochondrial membrane potential (MMP) through ATP hydrolysis (the so-called "reverse mode" of ATP synthase) is increased in brown fat. In cultured brown adipocytes, IF1 overexpression results in an inability of mitochondria to sustain the MMP upon adrenergic stimulation, leading to a quiescent-like phenotype in brown adipocytes. In mice, adeno-associated virus-mediated IF1 overexpression in BAT suppresses adrenergic-stimulated thermogenesis and decreases mitochondrial respiration in BAT. Taken together, our work identifies downregulation of IF1 upon cold as a critical event for the facilitation of the reverse mode of ATP synthase as well as to enable energetic adaptation of BAT to effectively support non-shivering thermogenesis.

Keywords:  Adipocytes; Metabolism; Mitochondria; Thermogenesis; UCP1

DOI:  https://doi.org/10.1038/s44318-024-00215-0
Leukemia. 2024 Sep 16.

Potent combination benefit of the AKT inhibitor capivasertib and the BCL-2 inhibitor venetoclax in diffuse large B cell lymphoma.

Brandon S Willis, Kevin Mongeon, Hannah Dry, India L Neveras, Nadezda Bryan, Meghana Pandya, Justine Roderick-Richardson, Wendan Xu, Li Yang, Alan Rosen, Corinne Reimer, Liliana Tuskova, Pavel Klener, Jerome T Mettetal, Georg Lenz, Simon T Barry.

The therapeutic potential of targeting PI3K/AKT/PTEN signalling in B-cell malignancies remains attractive. Whilst PI3K-α/δ inhibitors demonstrate clinical benefit in certain B-cell lymphomas, PI3K signalling inhibitors have been inadequate in relapsed/refractory diffuse large B-cell lymphoma (DLBCL) in part, due to treatment related toxicities. Clinically, AKT inhibitors exhibit a differentiated tolerability profile offering an alternative approach for treating patients with B-cell malignancies. To explore how AKT inhibition complements other potential therapeutics in the treatment of DLBCL patients, an in vitro combination screen was conducted across a panel of DLCBL cell lines. The AKT inhibitor, capivasertib, in combination with the BCL-2 inhibitor, venetoclax, produced notable therapeutic benefit in preclinical models of DLBCL. Capivasertib and venetoclax rapidly induced caspase and PARP cleavage in GCB-DLBCL PTEN wildtype cell lines and those harbouring PTEN mutations or reduced PTEN protein, driving prolonged tumour growth inhibition in DLBCL cell line and patient derived xenograft lymphoma models. The addition of the rituximab further deepened the durability of capivasertib and venetoclax responses in a RCHOP refractory DLBCL in vivo models. These findings provide preclinical evidence for the rational treatment combination of AKT and BCL-2 inhibitors using capivasertib and venetoclax respectively alongside anti-CD20 antibody supplementation for treatment of patients with DLBCL.

DOI: https://doi.org/10.1038/s41375-024-02401-9
Dis Model Mech. 2024 Sep 01. pii: dmm050814. [Epub ahead of print]17(9):

Metabolic ripple effects - deciphering how lipid metabolism in cancer interfaces with the tumor microenvironment.

Patrick B Jonker, Alexander Muir.

  Cancer cells require a constant supply of lipids. Lipids are a diverse class of hydrophobic molecules that are essential for cellular homeostasis, growth and survival, and energy production. How tumors acquire lipids is under intensive investigation, as these mechanisms could provide attractive therapeutic targets for cancer. Cellular lipid metabolism is tightly regulated and responsive to environmental stimuli. Thus, lipid metabolism in cancer is heavily influenced by the tumor microenvironment. In this Review, we outline the mechanisms by which the tumor microenvironment determines the metabolic pathways used by tumors to acquire lipids. We also discuss emerging literature that reveals that lipid availability in the tumor microenvironment influences many metabolic pathways in cancers, including those not traditionally associated with lipid biology. Thus, metabolic changes instigated by the tumor microenvironment have 'ripple' effects throughout the densely interconnected metabolic network of cancer cells. Given the interconnectedness of tumor metabolism, we also discuss new tools and approaches to identify the lipid metabolic requirements of cancer cells in the tumor microenvironment and characterize how these requirements influence other aspects of tumor metabolism.

Keywords:  Acidosis; Diet; Hypoxia; Lipid metabolism; Nutrient deprivation; Tumor microenvironment

DOI:  https://doi.org/10.1242/dmm.050814
Cancer Metab. 2024 Sep 16. 12(1): 27

Metabolism of primary high-grade serous ovarian carcinoma (HGSOC) cells under limited glutamine or glucose availability.

Daniela Šimčíková, Dominik Gardáš, Tomáš Pelikán, Lukáš Moráň, Martin Hruda, Kateřina Hložková, Tiziana Pivetta, Michal Hendrych, Júlia Starková, Lukáš Rob, Petr Vaňhara, Petr Heneberg.

   BACKGROUND: High-grade serous ovarian carcinoma (HGSOC) is the most common and aggressive subtype of epithelial ovarian carcinoma. It is primarily diagnosed at stage III or IV when the 5-year survival rate ranges between 20% and 40%. Here, we aimed to validate the hypothesis, based on HGSOC cell lines, that proposed the existence of two distinct groups of HGSOC cells with high and low oxidative phosphorylation (OXPHOS) metabolism, respectively, which are associated with their responses to glucose and glutamine withdrawal.
METHODS: We isolated and cultivated primary cancer cell cultures from HGSOC and nontransformed ovarian fibroblasts from the surrounding ovarium of 45 HGSOC patients. We tested the metabolic flexibility of the primary cells, particularly in response to glucose and glutamine depletion, analyzed and modulated endoplasmic reticulum stress, and searched for indices of the existence of previously reported groups of HGSOC cells with high and low OXPHOS metabolism.
RESULTS: The primary HGSOC cells did not form two groups with high and low OXPHOS that responded differently to glucose and glutamine availabilities in the cell culture medium. Instead, they exhibited a continuum of OXPHOS phenotypes. In most tumor cell isolates, the responses to glucose or glutamine withdrawal were mild and surprisingly correlated with those of nontransformed ovarian fibroblasts from the same patients. The growth of tumor-derived cells in the absence of glucose was positively correlated with the lipid trafficking regulator FABP4 and was negatively correlated with the expression levels of HK2 and HK1. The correlations between the expression of electron transport chain (ETC) proteins and the oxygen consumption rates or extracellular acidification rates were weak. ER stress markers were strongly expressed in all the analyzed tumors. ER stress was further potentiated by tunicamycin but not by the recently proposed ER stress inducers based on copper(II)-phenanthroline complexes. ER stress modulation increased autophagy in tumor cell isolates but not in nontransformed ovarian fibroblasts.
CONCLUSIONS: Analysis of the metabolism of primary HGSOC cells rejects the previously proposed hypothesis that there are distinct groups of HGSOC cells with high and low OXPHOS metabolism that respond differently to glutamine or glucose withdrawal and are characterized by ETC protein levels.

Keywords:  Epithelial ovarian carcinoma; Metabolism reprogramming; Ovarian fibroblasts; Oxidative phosphorylation; Patient-derived cells; Unfolded protein response

DOI:  https://doi.org/10.1186/s40170-024-00355-1
Gastric Cancer. 2024 Sep 19.

Lipolysis-stimulated lipoprotein receptor promote lipid uptake and fatty acid oxidation in gastric cancer.

Kota Kawabata, Tsuyoshi Takahashi, Koji Tanaka, Yukinori Kurokawa, Kazuyoshi Yamamoto, Takuro Saito, Kota Momose, Kotaro Yamashita, Tomoki Makino, Takashi Yokouchi, Kunihiko Kawai, Satoshi Serada, Minoru Fujimoto, Kiyokazu Nakajima, Tetsuji Naka, Hidetoshi Eguchi, Yuichiro Doki.

   BACKGROUND: Lipolysis-stimulated lipoprotein receptor (LSR), a lipid receptor, is associated with cancer progression. However, detailed effects on intracellular metabolism are unclear. We aimed to elucidate the mechanism of LSR-mediated lipid metabolism in gastric cancer.
METHODS: We investigated lipid metabolic changes induced by lipoprotein administration in gastric cancer cells and evaluated the significance of LSR expression and lipid droplets formation in gastric cancer patients. The efficacy of inhibiting β-oxidation in gastric cancer cells was also examined in vitro and vivo.
RESULTS: In gastric cancer cells, LSR promoted cellular uptake of lipoprotein and cell proliferation. Furthermore, the inhibition of LSR in gastric cancer cells expressing high levels of LSR counteracted both effects. Immunohistochemical analysis of human gastric cancer tissues showed that the increase in lipid droplets via LSR is a factor that influences prognosis. Lipidomics analysis of LSR-high-expressing gastric cancer cells revealed an increase in β-oxidation. Based on these results, we used etomoxir, a β-oxidation inhibitor, and found that it inhibited cell proliferation as well as the suppression of LSR. Similarly, in a mouse xenograft model of LSR-highly expressing gastric cancer cells, the tumor growth effect of high-fat diet feeding was counteracted by etomoxir, consistent with the Ki-67 labeling index.
CONCLUSIONS: We demonstrated that lipids are taken up into gastric cancer cells via LSR and cause an increase in β-oxidation, resulting in the promotion of cancer progression. Controlling LSR-mediated lipid metabolism may be a novel therapeutic strategy for gastric cancer.

Keywords:  Fatty acid oxidation; Gastric cancer; Lipid uptake; Lipolysis-stimulated lipoprotein receptor

DOI:  https://doi.org/10.1007/s10120-024-01552-z
JCI Insight. 2024 Sep 17. pii: e178645. [Epub ahead of print]

Quantitative proteomics of patient fibroblasts reveal biomarkers and diagnostic signatures of mitochondrial disease.

Sandrina P Correia, Marco F Moedas, Lucie S Taylor, Karin Naess, Albert Z Lim, Robert McFarland, Zuzanna Kazior, Anastasia Rumyantseva, Rolf Wibom, Martin Engvall, Helene Bruhn, Nicole Lesko, Ákos Végvári, Lukas Käll, Matthias Trost, Charlotte L Alston, Christoph Freyer, Robert W Taylor, Anna Wedell, Anna Wredenberg.

   BACKGROUND: Mitochondrial diseases belong to the group of inborn errors of metabolism (IEM), with a prevalence of 1:2,000-1:5,000. They are the most common form of IEM, but despite advances in next-generation sequencing technologies, almost half of the patients are left genetically undiagnosed.
METHODS: We investigated a cohort of 61 patients with defined mitochondrial disease to improve diagnostics, identify biomarkers, and correlate metabolic pathways to specific disease groups. Clinical presentations were structured using human phenotype ontology terms, and mass spectrometry-based proteomics was performed on primary fibroblasts. Additionally, we integrated six patients carrying variants of uncertain significance (VUS) to test proteomics as a diagnostic expansion.
RESULTS: Proteomic profiles from patient samples could be classified according to their biochemical and genetic characteristics, with the expression of five proteins (GPX4, MORF4L1, MOXD1, MSRA and TMED9) correlating with the disease cohort, and thus, acting as putative biomarkers. Pathway analysis showed a deregulation of inflammatory and mitochondrial stress responses. This included the upregulation of glycosphingolipid metabolism and mitochondrial protein import, as well as the downregulation of arachidonic acid metabolism. Furthermore, we could assign pathogenicity to a VUS in MRPS23 by demonstrating the loss of associated mitochondrial ribosome subunits.
CONCLUSION: We established mass spectrometry-based proteomics on patient fibroblasts as a viable and versatile tool for diagnosing patients with mitochondrial disease.
FUNDING: The NovoNordisk Foundation, Knut and Alice Wallenberg Foundation, Wellcome Centre for Mitochondrial Research, UK Medical Research Council, and the UK NHS Highly Specialised Service for Rare Mitochondrial Disorders of Adults and Children.

Keywords:  Metabolism; Mitochondria; Molecular diagnosis; Proteomics

DOI:  https://doi.org/10.1172/jci.insight.178645
Free Radic Biol Med. 2024 Sep 13. pii: S0891-5849(24)00663-4. [Epub ahead of print]

Ablating the glutaredoxin-2 (Glrx2) gene protects male mice against non-alcoholic fatty liver disease (NAFLD) by limiting oxidative distress.

Cathryn Grayson, Olivia Chalifoux, Mariana De Sa Tavares Russo, Daina Zofija Avizonis, Samantha Sterman, Ben Faerman, Olivia Koufos, Luis B Agellon, Ryan J Mailloux.

In the present study, we investigated the consequences of deleting the glutaredoxin-2 gene (Glrx2-/-) on the development of non-alcoholic fatty liver disease (NAFLD) in male and female C57BL6N mice fed a control (CD) or high-fat diet (HFD). We report that the HFD induced a significant increase in body mass in the wild-type (Wt) and Glrx2-/- male, but not female, mice, which was associated with the hypertrophying of the abdominal fat. Interestingly, while the Wt male mice fed the HFD developed NAFLD, the deletion of the Glrx2 gene mitigated vesicle formation, intrahepatic lipid accumulation, and fibrosis in the males. The protective effect associated with ablating the Glrx2 gene in male mice was due to enhancement of mitochondrial redox buffering capacity. Specifically, liver mitochondria from male Glrx2-/- fed a CD or HFD produced significantly less hydrogen peroxide (mtH2O2), had lower malondialdehyde levels, greater activities for glutathione peroxidase and thioredoxin reductase, and less protein glutathione mixed disulfides (PSSG) when compared to the Wt male mice fed the HFD. These effects correlated with the S-glutathionylation of α-ketoglutarate dehydrogenase (KGDH), a potent mtH2O2 source and key redox sensor in hepatic mitochondria. In comparison to the male mice, both Wt and Glrx2-/- female mice displayed almost complete resistance to HFD-induced body mass increases and the development of NAFLD, which was attributed to the superior redox buffering capacity of the liver mitochondria. Together, our findings show that modulation of mitochondrial S-glutathionylation signaling through Glrx2 augments resistance of male mice towards the development of NAFLD through preservation of mitochondrial redox buffering capacity. Additionally, our findings demonstrate the sex dimorphisms associated with the manifestation of NAFLD is related to the superior redox buffering capacity and modulation of the S-glutathionylome in hepatic mitochondria from female mice.

DOI: https://doi.org/10.1016/j.freeradbiomed.2024.09.016
Discov Oncol. 2024 Sep 17. 15(1): 451

Clinical efficacy and immune response of BCL-2 inhibitors combined with hypomethylating agents in the treatment of acute myeloid leukemia.

Xiaohuan Peng, Jianing Yu, Futian Tang, Yanhong Li, Jun Bai, Lijuan Li, Liansheng Zhang.

   OBJECTIVE: Acute myeloid leukemia (AML) is a malignant clonal proliferative disease with a high mortality rate. The combination therapy of BCL-2 inhibitor Venetoclax (VEN) and hypomethylating agents (HMAs) has significant anti-leukemia activity.
METHODS: We analyzed the efficacy, safety and immune response characteristics of AML patients who were unfit for high-dose chemotherapy and accepted the medication of VEN + HMAs.
RESULTS: After VEN + HMAs treatment, 31 newly diagnosed AML patients had the morphologic leukemia-free state rate (MLFS%) of 80.6% (25/31), complete response rate (CR%) of 54.8% (17/31), the minimal residual disease negative rate (MRD-%) of 51.6% (16/31), and the median progression-free survival (PFS) of 14 months. After treatment, the proportion of bone marrow primitive cells, the MRD level, white blood cell (WBC) count, fibrinogen (FIB) level and the proportion of B cells were significantly decreased. The red blood cell (RBC) count, hemoglobin (HGB) level, platelet count (PLT) count, activated partial thromboplastin time (APTT), the proportion of total T cells, CD8 + T cells and the IFN-γ level were significantly increased. After VEN + HMAs treatment, 12 relapsed AML patients had a MLFS% of 50% (6/12), CR% of 33.3% (4/12), MRD-% of 25% (3/12), and a median PFS of 7 months. After treatment, the proportion of bone marrow primitive cells and MRD level were slightly decreased, the proportions of CD8 + T cells and NK cells were significantly increased, the proportion of B cells and IL-10 level were significantly decreased. 12 AML patients who receive microtransplantation (MST) treatment using VEN + HMAs as a pretreatment regimen had a PFS of 20.5 months, which was much greater than VEN + HMAs group alone. Hematological recovery was better in the MST group with significantly increased RBC count, HGB level and PLT count. The most common adverse events were myelosuppression, agranulocytosis, infection and cardiovascular toxicity. No fatal adverse events were reported.
CONCLUSION: The combination of BCL-2 inhibitors and HMAs had good efficacy and safety in AML patients who were unfit for high-dose chemotherapy, which may improve the immune microenvironment and enhance anti-leukemia immune response.

Keywords:  Acute myeloid leukemia; BCL-2 inhibitors; Clinical efficacy; Hypomethylating agents; Immune response

DOI:  https://doi.org/10.1007/s12672-024-01348-8
Gastroenterology. 2024 Sep 17. pii: S0016-5085(24)05464-7. [Epub ahead of print]

Obesity facilitated colon cancer progression is mediated by increased diacylglycerol o-acyltransferases 1 and 2 (DGAT1/2) levels.

Jenisha Ghimire, Morgan E Collins, Patricia Snarski, Angelle N King, Emmanuelle Ruiz, Rida Iftikhar, Harrison M Penrose, Krzysztof Moroz, Tyler Rorison, Melody Baddoo, Muhammad Anas Naeem, Arnold H Zea, Scott T Magness, Erik F Flemington, Susan E Crawford, Suzana D Savkovic.

   BACKGROUND & AIMS: The obesity epidemic is associated with increased colon cancer progression. As lipid droplets (LDs) fuel tumor growth, we aim to determine the significance of diacyltransferases, DGAT1/2, responsible for LDs biogenesis, in obesity-mediated colonic tumorigenesis.
METHODS: Human colon cancer samples, colon cancer cells, colonospheres, and ApcMin/+ colon cancer mouse model on a high-fat diet were employed. For DGAT1/2 inhibition, enzymatic inhibitors and siRNA were used. Expression, pathways, cell cycle, and growth were assessed. Bioinformatic analyses of CUT&RUN and RNAseq data were performed.
RESULTS: DGAT1/2 levels in human colon cancer tissue are significantly elevated with disease severity and obesity (vs normal). Their levels are increased in human colon cancer cells (vs non-transformed) and further enhanced by fatty acids prevalent in obesity; augmented DGAT2 expression is MYC-dependent. Inhibition of DGAT1/2 improves FOXO3 activity by attenuating PI3K, resulting in reduced MYC-dependent DGAT2 expression and LDs accumulation, suggesting feedback. This inhibition attenuated growth in colon cancer cells and colonospheres via FOXO3/p27kip1 cell cycle arrest and reduced colonic tumors in ApcMin/+ mice on a high-fat diet. Transcriptomic analysis revealed that DGAT1/2 inhibition targeted metabolic and tumorigenic pathways in human colon cancer and colon cancer crypts, stratifying human colon cancer samples from normal. Further analysis revealed that this inhibition is predictive of advanced disease-free state and survival in colon cancer patients.
CONCLUSION: This is a novel mechanism of DGAT1/2-dependent metabolic and tumorigenic remodeling in obesity-facilitated colon cancer, providing a platform for the future development of effective treatments for colon cancer patients.

Keywords:  Colon Cancer; DGAT1; DGAT2; FOXO3; Lipid Droplets; Obesity

DOI:  https://doi.org/10.1053/j.gastro.2024.09.011
Front Immunol. 2024 ;15 1430352

Exploiting branched-chain amino acid metabolism and NOTCH3 expression to predict and target colorectal cancer progression.

Kuan Shen, Chuming Zhu, Jianjun Wu, Jiang Yan, Pengyu Li, Shuqing Cao, Xinyi Zhou, Guozhong Yao.

   Background: The interplay between colon adenocarcinoma (COAD) and branched-chain amino acid (BCAA) metabolism is not fully understood, presenting a crucial area for investigation.
Methods: We developed a prognostic model based on BCAA metabolism using the least absolute shrinkage and selection operator (LASSO) regression algorithm. We employed qRT-PCR and Western blot analyses to examine NOTCH3 expression in COAD tissues versus adjacent non-cancerous tissues and various cell lines. We also investigated the impact of NOTCH3 on COAD cell proliferation, invasion, and migration through in vitro and in vivo experiments.
Results: Our BCAA metabolism-related signature (BRS) distinguished between different immune features, tumor mutation burdens, responses to immunotherapy, and drug sensitivity among COAD patients. NOTCH3 was found to be overexpressed in COAD, promoting tumor growth as verified through various assays. The model effectively predicted COAD prognosis and patient responses to treatments, underscoring the potential of BCAA pathways as therapeutic targets.
Conclusion: The BRS is instrumental in predicting the prognosis and therapeutic response in COAD, with NOTCH3 playing a significant role in the proliferation, invasion and migration of COAD. These findings suggest that targeting BCAA metabolism and NOTCH3 could advance COAD treatment strategies.

Keywords:  NOTCH3; branched-chain amino acids; colorectal cancer; single-cell sequencing; tumor microenvironment

DOI:  https://doi.org/10.3389/fimmu.2024.1430352
Am J Physiol Cell Physiol. 2024 Sep 16.

Bone Marrow Stromal Cells Enhance Differentiation of Acute Myeloid Leukemia Induced by Pyrimidine Synthesis Inhibitors.

Tomislav Smoljo, Hrvoje Lalic, Vilma Dembitz, Barbara Tomic, Josip Batinic, Radovan Vrhovac, Antonio Bedalov, Dora Visnjic.

  Acute myeloid leukemia (AML) is a heterogeneous group of hematologic malignancies characterized by differentiation arrest, high relapse rates, and poor survival. The bone marrow (BM) microenvironment is recognized as a critical mediator of drug resistance and a primary site responsible for AML relapse. Our previous study reported that 5-aminoimidazole-4-carboxamide ribonucleoside (AICAr) induces AML cell differentiation by inhibiting pyrimidine synthesis and activating Checkpoint kinase 1. While the protective effect of BM stroma on leukemia cells in response to cytotoxic drugs is well-documented, its effect on AML differentiation remains less explored. In this study, we investigated the impact of stromal cell lines and primary mesenchymal stromal cells (MSCs) on AML cell line differentiation triggered by AICAr and brequinar, a known dihydroorotate dehydrogenase (DHODH) inhibitor. Our findings indicate that the mouse MS-5 stromal cell line, known for its cytoprotective effects, does not inhibit AML cell differentiation induced by pyrimidine synthesis inhibitors. Interestingly, AICAr caused morphological changes and growth arrest in MS-5 stromal cells via an AMPK-dependent pathway. Human stromal cell lines HS-5 and HS-27, as well as primary MSCs isolated from patient bone marrow, were superior in promoting AML differentiation compared to mouse cells in response to AICAr and brequinar, with the inhibitors not significantly affecting the stromal cells themselves. In conclusion, our study highlights the supportive role of human BM MSCs in enhancing the differentiation effects of pyrimidine synthesis inhibitors on AML cells, suggesting that AML treatment strategies focusing on differentiation rather than cell killing may be successful in clinical settings.

Keywords:  AICAr; acute myeloid leukemia; bone marrow stromal cells; brequinar; differentiation

DOI:  https://doi.org/10.1152/ajpcell.00413.2024
Cancer Res Commun. 2024 Sep 20.

Oncogenic Mutant p53 Sensitizes Non-Small Cell Lung Cancer Cells to Proteasome Inhibition via Oxidative Stress-Dependent Induction of Mitochondrial Apoptosis.

Kranthi Kumar Chougoni, Victoria Neely, Boxiao Ding, Eziafa Oduah, Vianna T Lam, Bin Hu, Jennifer E Koblinski, Bradford E Windle, Swati Palit Deb, Sumitra Deb, Jorge J Nieva, Senthil K Radhakrishnan, Hisashi Harada, Steven R Grossman.

Non-small cell lung cancer (NSCLC) cells with oncogenic mutant p53 alleles (Onc-p53) exhibit significantly higher levels of proteasome activity, indicating that Onc-p53 induces proteotoxic stress which may be leveraged as a therapeutic vulnerability. Proteasome inhibitors (PIs) are most active in cells under proteotoxic stress, so we investigated whether PIs exhibit preferential cytotoxicity in Onc-p53 NSCLC cells. Indeed, BTZ and other PIs exhibited IC50 values 6-15-fold lower in Onc-p53 cells vs. wild-type (WT) p53 cells. BTZ cytotoxic effects in Onc-p53 cells were abrogated by antioxidants such as N-acetyl L-cysteine, indicating that oxidative stress is the critical driver of BTZ-dependent cytotoxic effects in Onc-p53 cells. Importantly, we observed oxidative stress-dependent transcriptional induction of the pro-apoptotic BH3-only protein NOXA leading to cleavage of caspase-3, consistent with an apoptotic mechanism of cell death in Onc-p53 but not in WT p53 cells treated with BTZ. BTZ-generated oxidative stress was linked to nuclear translocation of NRF2 and transcriptional activation of ATF3, which in turn was required for NOXA induction. Validating BTZ's translational potential in Onc-p53 NSCLC cells, BTZ and the BH3-mimetic navitoclax were synergistically cytotoxic in Onc-p53 but not WT p53 cells in vitro, and BTZ effectively limited growth of Onc-p53 NSCLC xenografts when combined with navitoclax and carboplatin (a standard of care chemotherapeutic in NSCLC) in vivo. Our data therefore support further investigation of the therapeutic utility of PIs combined with BH3-mimetics and chemotherapy in Onc-p53 human NSCLC as a novel therapeutic strategy.

DOI: https://doi.org/10.1158/2767-9764.CRC-23-0637