1
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Liu W, Hsieh HT, He Z, Xiao X, Song C, Lee EX, Dong J, Lei CL, Wang J, Chen G. Medium acidosis drives cardiac differentiation during mesendoderm cell fate specification from human pluripotent stem cells. Stem Cell Reports 2024:S2213-6711(24)00221-2. [PMID: 39178847 DOI: 10.1016/j.stemcr.2024.07.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 07/27/2024] [Accepted: 07/29/2024] [Indexed: 08/26/2024] Open
Abstract
Effective lineage-specific differentiation is essential to fulfilling the great potentials of human pluripotent stem cells (hPSCs). In this report, we investigate how modulation of medium pH and associated metabolic changes influence mesendoderm differentiation from hPSCs. We show that daily medium pH fluctuations are critical for the heterogeneity of cell fates in the absence of exogenous inducers. Acidic environment alone leads to cardiomyocyte generation without other signaling modulators. In contrast, medium alkalinization is inhibitory to cardiac fate even in the presence of classic cardiac inducers. We then demonstrate that acidic environment suppresses glycolysis to facilitate cardiac differentiation, while alkaline condition promotes glycolysis and diverts the differentiation toward other cell types. We further show that glycolysis inhibition or AMPK activation can rescue cardiac differentiation under alkalinization, and glycolysis inhibition alone can drive cardiac cell fate. This study highlights that pH changes remodel metabolic patterns and modulate signaling pathways to control cell fate.
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Affiliation(s)
- Weiwei Liu
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Macau SAR, China; Biological Imaging and Stem Cell Core Facility, Faculty of Health Sciences, University of Macau, Macau SAR, China.
| | - Hsun-Ting Hsieh
- Biological Imaging and Stem Cell Core Facility, Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Ziqing He
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Macau SAR, China; GMU-GIBH Joint School of Life Sciences, The Guangdong-Hong Kong-Macau Joint Laboratory for Cell Fate Regulation and Diseases, Guangzhou National Laboratory, Guangzhou Medical University, Guangzhou, China
| | - Xia Xiao
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Chengcheng Song
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - En Xin Lee
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Ji Dong
- GMU-GIBH Joint School of Life Sciences, The Guangdong-Hong Kong-Macau Joint Laboratory for Cell Fate Regulation and Diseases, Guangzhou National Laboratory, Guangzhou Medical University, Guangzhou, China; Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Chon Lok Lei
- Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Jiaxian Wang
- HELP Stem Cell Innovations Ltd. Co., Nanjing, Jiangsu, China
| | - Guokai Chen
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Macau SAR, China; MoE Frontiers Science Center for Precision Oncology, University of Macau, Macau SAR, China; Zhuhai UM Science & Technology Research Institute, Zhuhai, China.
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2
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Romero-Moreno R, Czowski BJ, Harris L, Kuehn JF, White KA. Intracellular pH differentially regulates transcription of metabolic and signaling pathways in normal epithelial cells. J Biol Chem 2024:107658. [PMID: 39128712 DOI: 10.1016/j.jbc.2024.107658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2024] [Accepted: 07/31/2024] [Indexed: 08/13/2024] Open
Abstract
Intracellular pH (pHi) dynamics regulate normal cell function, and dysregulated pHi dynamics is an emerging hallmark of cancer (constitutively increased pHi) and neurodegeneration (constitutively decreased pHi). However, the molecular mechanisms by which pHi dynamics regulate cell biology are poorly understood. Here, we discovered that altering pHi in normal human breast epithelial cells triggers global transcriptional changes. We identified 176 genes differentially regulated by pHi, with pHi-dependent genes clustering in signaling and glycolytic pathways. Using various normal epithelial cell models, we showed pH-dependent Notch1 expression, with increased protein abundance at high pHi. This resulted in pH-dependent downstream signaling, with increased Notch1 signaling at high pHi. We also found that high pHi increased the expression of glycolytic enzymes and regulators of pyruvate fate, including lactate dehydrogenase and pyruvate dehydrogenase kinase. These transcriptional changes were sufficient to alter lactate production, with high pHi shifting these normal epithelial cells toward a glycolytic metabolism and increasing lactate production. Thus, pHi dynamics transcriptionally regulate signaling and metabolic pathways in normal epithelial cells. Our data reveal new molecular regulators of pHi-dependent biology and a role for increased pHi in driving the acquisition of cancer-associated signaling and metabolic changes in normal human epithelial cells.
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Affiliation(s)
- Ricardo Romero-Moreno
- Harper Cancer Research Institute, South Bend. IN, 46617, USA; Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Brandon J Czowski
- Harper Cancer Research Institute, South Bend. IN, 46617, USA; Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Lindsey Harris
- Harper Cancer Research Institute, South Bend. IN, 46617, USA; Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Jessamine F Kuehn
- Harper Cancer Research Institute, South Bend. IN, 46617, USA; Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Katharine A White
- Harper Cancer Research Institute, South Bend. IN, 46617, USA; Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA.
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3
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Didan Y, Ghomlaghi M, Nguyen LK, Ng DCH. Stress pathway outputs are encoded by pH-dependent clustering of kinase components. Nat Commun 2024; 15:6614. [PMID: 39103333 DOI: 10.1038/s41467-024-50638-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 07/10/2024] [Indexed: 08/07/2024] Open
Abstract
Signal processing by intracellular kinases controls near all biological processes but how signal pathway functions evolve with changed cellular context is poorly understood. Functional specificity of c-Jun N-terminal Kinases (JNK) are partly encoded by signal strength. Here we reveal that intracellular pH (pHi) is a significant component of the JNK network and defines signal response to specific stimuli. We show pHi regulates JNK activity in response to cell stress, with the relationship between pHi and JNK activity dependent on specific stimuli and upstream kinases activated. Using the optogenetic clustering tag CRY2, we show that an increase in pHi promotes the light-induced phase transition of ASK1 to augment JNK activation. While increased pHi similarly promoted CRY2-tagged JNK2 to form light-induced condensates, this attenuated JNK activity. Mathematical modelling of feedback signalling incorporating pHi and differential contributions by ASK1 and JNK2 condensates was sufficient to delineate signal responses to specific stimuli. Taking pHi and ASK1/JNK2 signal contributions into consideration may delineate oncogenic versus tumour suppressive JNK functions and cancer cell drug responses.
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Affiliation(s)
- Yuliia Didan
- School of Biomedical Science, Faculty of Medicine, University of Queensland; St Lucia, Brisbane, Australia
| | - Milad Ghomlaghi
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Australia
- Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Lan K Nguyen
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Australia
- Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Dominic C H Ng
- School of Biomedical Science, Faculty of Medicine, University of Queensland; St Lucia, Brisbane, Australia.
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4
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Lund LM, Marchi AN, Alderfer L, Hall E, Hammer J, Trull KJ, Hanjaya-Putra D, White KA. Intracellular pH dynamics respond to microenvironment stiffening and mediate vasculogenic mimicry through β-catenin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.04.597454. [PMID: 38895391 PMCID: PMC11185592 DOI: 10.1101/2024.06.04.597454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Dysregulated intracellular pH (pHi) dynamics and an altered tumor microenvironment have emerged as drivers of cancer cell phenotypes. However, the molecular integration between the physical properties of the microenvironment and dynamic intracellular signaling responses remains unclear. Here, we use two metastatic cell models, one breast and one lung, to assess pHi response to varying extracellular matrix (ECM) stiffness. To experimentally model ECM stiffening, we use two tunable-stiffness hydrogel systems: Matrigel and hyaluronic acid (HA) gels, which mimic the increased protein secretion and crosslinking associated with ECM stiffening. We find that single-cell pHi decreases with increased ECM stiffness in both hydrogel systems and both metastatic cell types. We also observed that stiff ECM promotes vasculogenic mimicry (VM), a phenotype associated with metastasis and resistance. Importantly, we show that decreased pHi is both a necessary and sufficient mediator of VM, as raising pHi on stiff ECM reduces VM phenotypes and lowering pHi on soft ECM drives VM. We characterize β-catenin as a pH-dependent molecular mediator of pH-dependent VM, where stiffness-driven changes in β-catenin abundance can be overridden by increased pHi. We uncover a dynamic relationship between matrix stiffness and pHi, thus suggesting pHi dynamics can override mechanosensitive cell responses to the extracellular microenvironment.
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Affiliation(s)
- Leah M Lund
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN 46556 USA
- Harper Cancer Research Institute, University of Notre Dame, 1234 N. Notre Dame Avenue, South Bend, IN 46617 USA
| | - Angelina N Marchi
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN 46556 USA
- Harper Cancer Research Institute, University of Notre Dame, 1234 N. Notre Dame Avenue, South Bend, IN 46617 USA
| | - Laura Alderfer
- Bioengineering Graduate Program, Aerospace and Mechanical Engineering, University of Notre Dame, 153 Multidisciplinary Engineering Research Building, Notre Dame, IN 46556 USA
- Current: Vivodyne, Suite 775 601 Walnut Street, Philadelphia PA 19106 USA
| | - Eva Hall
- Bioengineering Graduate Program, Aerospace and Mechanical Engineering, University of Notre Dame, 153 Multidisciplinary Engineering Research Building, Notre Dame, IN 46556 USA
| | - Jacob Hammer
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN 46556 USA
- Harper Cancer Research Institute, University of Notre Dame, 1234 N. Notre Dame Avenue, South Bend, IN 46617 USA
| | - Keelan J Trull
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN 46556 USA
- Harper Cancer Research Institute, University of Notre Dame, 1234 N. Notre Dame Avenue, South Bend, IN 46617 USA
| | - Donny Hanjaya-Putra
- Harper Cancer Research Institute, University of Notre Dame, 1234 N. Notre Dame Avenue, South Bend, IN 46617 USA
- Bioengineering Graduate Program, Aerospace and Mechanical Engineering, University of Notre Dame, 153 Multidisciplinary Engineering Research Building, Notre Dame, IN 46556 USA
- Chemical and Biomolecular Engineering, University of Notre Dame, 250 Nieuwland Hall, Notre Dame, IN 46556 USA
| | - Katharine A White
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN 46556 USA
- Harper Cancer Research Institute, University of Notre Dame, 1234 N. Notre Dame Avenue, South Bend, IN 46617 USA
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5
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Xu Y, Yu Y, Yan R, Ke X, Qu Y. Modulating β-catenin homeostasis for cancer therapy. Trends Cancer 2024; 10:507-518. [PMID: 38521655 DOI: 10.1016/j.trecan.2024.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 02/05/2024] [Accepted: 02/26/2024] [Indexed: 03/25/2024]
Abstract
β-Catenin is a well-established driver of many cancers; however, there are challenges in developing agents targeting β-catenin for clinical use. Recent progress has indicated that most of the pathological changes in β-catenin may be commonly caused by loss of protein homeostasis. Modulation of β-catenin homeostasis, especially by hyperactivation of β-catenin, potentially leads to robust antitumor outcomes. Here, we comprehensively dissect the protein homeostasis of β-catenin in terms of time, compartmentalization, supramolecular assemblies, and dynamics, with emphasis on changes in β-catenin homeostasis upon oncogenic mutations. We propose that altered β-catenin homeostasis could be deleterious for β-catenin-dependent cancers and that modulation of β-catenin homeostasis offers a novel avenue for targeting β-catenin for cancer therapy.
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Affiliation(s)
- Yu Xu
- Center for Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, P.R. China
| | - Ying Yu
- Center for Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, P.R. China
| | - Rong Yan
- Center for Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, P.R. China
| | - Xisong Ke
- Center for Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, P.R. China.
| | - Yi Qu
- Center for Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, P.R. China.
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6
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Wang X, Qian H, Yang L, Yan S, Wang H, Li X, Yang D. The role and mechanism of IFITM1 in developing acquired cisplatin resistance in small cell lung cancer. Heliyon 2024; 10:e30806. [PMID: 38803858 PMCID: PMC11128842 DOI: 10.1016/j.heliyon.2024.e30806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 05/03/2024] [Accepted: 05/06/2024] [Indexed: 05/29/2024] Open
Abstract
Platinum-based chemotherapies, historically the cornerstone of first-line treatment for small-cell lung cancer (SCLC), face a major hurdle: the frequent emergence of chemoresistance, notably to cisplatin (CDDP). Current understanding of the mechanisms driving CDDP resistance in SCLC is incomplete. Notably, Interferon inducible transmembrane protein1 (IFITM1) has been identified as a key player in the distant metastasis of SCLC. Analysis of The Cancer Genome Atlas (TCGA) database revealed that IFITM1 expression is markedly elevated in tumor tissues as compared to that from adjacent normal tissues, correlating with a worse prognosis for patients with SCLC. Our research focused on investigating the role of IFITM1 in the acquisition of cisplatin resistance in SCLC. Further clinical sample analysis highlighted a significant increase in IFITM1 levels in SCLC tissues from cisplatin-resistant patients versus those were responsive to CCDP treatment, with similar trends observed in cisplatin-resistant SCLC cells. Crucially, overexpression of IFITM1 reduced the sensitivity of SCLC cells to cisplatin, while silencing IFITM1 enhanced chemosensitivity in cisplatin-resistant strains. Our in vivo studies further confirmed that silencing IFITM1 significantly boosted the efficacy of cisplatin in inhibiting growth of subcutaneous tumors of NCI-H466/CDDP cells (cisplatin-resistant SCLC cells) in a mouse model. Mechanistically, IFITM1 appears to foster cisplatin resistance through activation of the Wnt/β-catenin pathway. In summary, our findings suggest that targeting IFITM1, alongside cisplatin treatment, could offer a promising therapeutic strategy to overcome resistance and improve outcomes for SCLC patients.
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Affiliation(s)
- Xuemei Wang
- Department of Oncology, The Sixth Affiliated Hospital of Kunming Medical University, China
| | - Haihong Qian
- Department of Oncology, The Sixth Affiliated Hospital of Kunming Medical University, China
| | - Ling Yang
- Department of Oncology, The Sixth Affiliated Hospital of Kunming Medical University, China
| | - Shuangli Yan
- Department of Oncology, The Sixth Affiliated Hospital of Kunming Medical University, China
| | - Hua Wang
- Department of Oncology, The Sixth Affiliated Hospital of Kunming Medical University, China
| | - Xiu Li
- Department of Oncology, The Sixth Affiliated Hospital of Kunming Medical University, China
| | - Donghai Yang
- Department of Oncology, The Sixth Affiliated Hospital of Kunming Medical University, China
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7
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Kisor KP, Ruiz DG, Jacobson MP, Barber DL. A role for pH dynamics regulating transcription factor DNA binding selectivity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.21.595212. [PMID: 38826444 PMCID: PMC11142074 DOI: 10.1101/2024.05.21.595212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Intracellular pH (pHi) dynamics regulates diverse cell processes such as proliferation, dysplasia, and differentiation, often mediated by the protonation state of a functionally critical histidine residue in endogenous pH sensing proteins. How pHi dynamics can directly regulate gene expression and whether transcription factors can function as pH sensors has received limited attention. We tested the prediction that transcription factors with a histidine in their DNA binding domain (DBD) that forms hydrogen bonds with nucleotides can have pH-regulated activity, which is relevant to more than 85 transcription factors in distinct families, including FOX, KLF, SOX and MITF/Myc. Focusing on FOX family transcription factors, we used unbiased SELEX-seq to identify pH-dependent DNA binding motif preferences, then confirm pH-regulated binding affinities for FOXC2, FOXM1, and FOXN1 to a canonical FkhP DNA motif that are 2.5 to 7.5 greater at pH 7.0 compared with pH 7.5. For FOXC2, we also find greater activity for an FkhP motif at lower pHi in cells and that pH-regulated binding and activity are dependent on a conserved histidine (His122) in the DBD. RNA-seq with FOXC2 also reveals pH-dependent differences in enriched promoter motifs. Our findings identify pH-regulated transcription factor-DNA binding selectivity with relevance to how pHi dynamics can regulate gene expression for myriad cell behaviours.
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8
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Park S, Lim YJ, Kim HS, Shin HJ, Kim JS, Lee JN, Lee JH, Bae S. Phloroglucinol Enhances Anagen Signaling and Alleviates H 2O 2-Induced Oxidative Stress in Human Dermal Papilla Cells. J Microbiol Biotechnol 2024; 34:812-827. [PMID: 38480001 DOI: 10.4014/jmb.2311.11047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 02/14/2024] [Accepted: 02/27/2024] [Indexed: 05/16/2024]
Abstract
Phloroglucinol (PG) is one of the abundant isomeric benzenetriols in brown algae. Due to its polyphenolic structure, PG exhibits various biological activities. However, the impact of PG on anagen signaling and oxidative stress in human dermal papilla cells (HDPCs) is unknown. In this study, we investigated the therapeutic potential of PG for improving hair loss. A non-cytotoxic concentration of PG increased anagen-inductive genes and transcriptional activities of β-Catenin. Since several anagen-inductive genes are regulated by β-Catenin, further experiments were performed to elucidate the molecular mechanism by which PG upregulates anagen signaling. Various biochemical analyses revealed that PG upregulated β-Catenin signaling without affecting the expression of Wnt. In particular, PG elevated the phosphorylation of protein kinase B (AKT), leading to an increase in the inhibitory phosphorylation of glycogen synthase kinase 3 beta (GSK3β) at serine 9. Treatment with the selective phosphoinositide 3-kinase/AKT inhibitor, LY294002, restored the increased AKT/GSK3β/β-Catenin signaling and anagen-inductive proteins induced by PG. Moreover, conditioned medium from PG-treated HDPCs promoted the proliferation and migration of human epidermal keratinocytes via the AKT signaling pathway. Subsequently, we assessed the antioxidant activities of PG. PG ameliorated the elevated oxidative stress markers and improved the decreased anagen signaling in hydrogen peroxide (H2O2)-induced HDPCs. The senescence-associated β-galactosidase staining assay also demonstrated that the antioxidant abilities of PG effectively mitigated H2O2-induced senescence. Overall, these results indicate that PG potentially enhances anagen signaling and improves oxidative stress-induced cellular damage in HDPCs. Therefore, PG can be employed as a novel therapeutic component to ameliorate hair loss symptoms.
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Affiliation(s)
- Seokmuk Park
- Department of Cosmetics Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Ye Jin Lim
- Department of Cosmetics Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Hee Su Kim
- Department of Cosmetics Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Hee-Jae Shin
- Department of Cosmetics Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Ji-Seon Kim
- Department of Cosmetics Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Jae Nam Lee
- Department of Cosmetology, Graduate School of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Jae Ho Lee
- Department of Cosmetics Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Seunghee Bae
- Department of Cosmetics Engineering, Konkuk University, Seoul 05029, Republic of Korea
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9
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Stock C. pH-regulated single cell migration. Pflugers Arch 2024; 476:639-658. [PMID: 38214759 PMCID: PMC11006768 DOI: 10.1007/s00424-024-02907-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/21/2023] [Accepted: 01/02/2024] [Indexed: 01/13/2024]
Abstract
Over the last two decades, extra- and intracellular pH have emerged as fundamental regulators of cell motility. Fundamental physiological and pathological processes relying on appropriate cell migration, such as embryonic development, wound healing, and a proper immune defense on the one hand, and autoimmune diseases, metastatic cancer, and the progression of certain parasitic diseases on the other, depend on surrounding pH. In addition, migrating single cells create their own localized pH nanodomains at their surface and in the cytosol. By this means, the migrating cells locally modulate their adhesion to, and the re-arrangement and digestion of, the extracellular matrix. At the same time, the cytosolic nanodomains tune cytoskeletal dynamics along the direction of movement resulting in concerted lamellipodia protrusion and rear end retraction. Extracellular pH gradients as found in wounds, inflamed tissues, or the periphery of tumors stimulate directed cell migration, and long-term exposure to acidic conditions can engender a more migratory and invasive phenotype persisting for hours up to several generations of cells after they have left the acidic milieu. In the present review, the different variants of pH-dependent single cell migration are described. The underlying pH-dependent molecular mechanisms such as conformational changes of adhesion molecules, matrix protease activity, actin (de-)polymerization, and signaling events are explained, and molecular pH sensors stimulated by H+ signaling are presented.
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Affiliation(s)
- Christian Stock
- Department of Gastroenterology, Hepatology, Infectiology & Endocrinology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
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10
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Czowski BJ, White KA. Intracellular pH regulates β-catenin with low pHi increasing adhesion and signaling functions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.22.586349. [PMID: 38585883 PMCID: PMC10996556 DOI: 10.1101/2024.03.22.586349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Intracellular pH (pHi) dynamics are linked to cell processes including proliferation, migration, and differentiation. The adherens junction (AJ) and signaling protein β-catenin has decreased abundance at high pHi due to increased proteasomal-mediated degradation. However, the effects of low pHi on β-catenin abundance and functions have not been characterized. Here, we show that low pHi stabilizes β-catenin in epithelial cells using population-level and single-cell assays. β-catenin abundance is increased at low pHi and decreased at high pHi. We also assay single-cell protein degradation rates to show that β-catenin half-life is longer at low compared to high pHi. Importantly, we show that AJs are not disrupted by β-catenin loss at high pHi due to rescue by plakoglobin. Finally, we show that low pHi increases β-catenin transcriptional activity in single cells and is indistinguishable from a Wnt-on state. This work characterizes pHi as a rheostat regulating β-catenin abundance, stability, and function and implicates β-catenin as a molecular mediator of pHi-dependent cell processes.
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Affiliation(s)
- Brandon J Czowski
- Department of Chemistry and Biochemistry, University of Notre Dame
- Harper Cancer Research Institute, University of Notre Dame
| | - Katharine A White
- Department of Chemistry and Biochemistry, University of Notre Dame
- Harper Cancer Research Institute, University of Notre Dame
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11
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Kazyken D, Lentz SI, Wadley M, Fingar DC. Alkaline intracellular pH (pHi) increases PI3K activity to promote mTORC1 and mTORC2 signaling and function during growth factor limitation. J Biol Chem 2023; 299:105097. [PMID: 37507012 PMCID: PMC10477693 DOI: 10.1016/j.jbc.2023.105097] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/14/2023] [Accepted: 07/17/2023] [Indexed: 07/30/2023] Open
Abstract
The conserved protein kinase mTOR (mechanistic target of rapamycin) responds to diverse environmental cues to control cell metabolism and promote cell growth, proliferation, and survival as part of two multiprotein complexes, mTOR complex 1 (mTORC1) and mTORC2. Our prior work demonstrated that an alkaline intracellular pH (pHi) increases mTORC2 activity and cell survival in complete media in part by activating AMP-activated protein kinase, a kinase best known to sense energetic stress. It is important to note that an alkaline pHi represents an underappreciated hallmark of cancer cells that promotes their oncogenic behaviors. In addition, mechanisms that control mTORC1 and mTORC2 signaling and function remain incompletely defined, particularly in response to stress conditions. Here, we demonstrate that an alkaline pHi increases phosphatidylinositide 3-kinase (PI3K) activity to promote mTORC1 and mTORC2 signaling in the absence of serum growth factors. Alkaline pHi increases mTORC1 activity through PI3K-Akt signaling, which mediates inhibitory phosphorylation of the upstream proteins tuberous sclerosis complex 2 and proline-rich Akt substrate of 40 kDa and dissociates tuberous sclerosis complex from lysosomal membranes, thus enabling Rheb-mediated activation of mTORC1. Thus, alkaline pHi mimics growth factor-PI3K signaling. Functionally, we also demonstrate that an alkaline pHi increases cap-dependent protein synthesis through inhibitory phosphorylation of eIF4E binding protein 1 and suppresses apoptosis in a PI3K- and mTOR-dependent manner. We speculate that an alkaline pHi promotes a low basal level of cell metabolism (e.g., protein synthesis) that enables cancer cells within growing tumors to proliferate and survive despite limiting growth factors and nutrients, in part through elevated PI3K-mTORC1 and/or PI3K-mTORC2 signaling.
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Affiliation(s)
- Dubek Kazyken
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
| | - Stephen I Lentz
- Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Maxwell Wadley
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Diane C Fingar
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
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12
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Liu Y, Reyes E, Castillo-Azofeifa D, Klein OD, Nystul T, Barber DL. Intracellular pH dynamics regulates intestinal stem cell lineage specification. Nat Commun 2023; 14:3745. [PMID: 37353491 PMCID: PMC10290085 DOI: 10.1038/s41467-023-39312-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 06/06/2023] [Indexed: 06/25/2023] Open
Abstract
Intracellular pH dynamics is increasingly recognized to regulate myriad cell behaviors. We report a finding that intracellular pH dynamics also regulates adult stem cell lineage specification. We identify an intracellular pH gradient in mouse small intestinal crypts, lowest in crypt stem cells and increasing along the crypt column. Disrupting this gradient by inhibiting H+ efflux by Na+/H+ exchanger 1 abolishes crypt budding and blocks differentiation of Paneth cells, which are rescued with exogenous WNT. Using single-cell RNA sequencing and lineage tracing we demonstrate that intracellular pH dynamics acts downstream of ATOH1, with increased pH promoting differentiation toward the secretory lineage. Our findings indicate that an increase in pH is required for the lineage specification that contributes to crypt maintenance, establishing a role for intracellular pH dynamics in cell fate decisions within an adult stem cell lineage.
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Affiliation(s)
- Yi Liu
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Efren Reyes
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California San Francisco, San Francisco, CA, 94143, USA
| | - David Castillo-Azofeifa
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California San Francisco, San Francisco, CA, 94143, USA
- Immunology Discovery, Genentech, Inc., South San Francisco, CA, 94080, USA
| | - Ophir D Klein
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Todd Nystul
- Departments of Anatomy, University of California San Francisco, San Francisco, CA, 94143, USA.
| | - Diane L Barber
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, CA, 94143, USA.
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13
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Warwicker J. The Physical Basis for pH Sensitivity in Biomolecular Structure and Function, With Application to the Spike Protein of SARS-CoV-2. Front Mol Biosci 2022; 9:834011. [PMID: 35252354 PMCID: PMC8894873 DOI: 10.3389/fmolb.2022.834011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 01/19/2022] [Indexed: 11/24/2022] Open
Abstract
Since pH sensitivity has a fundamental role in biology, much effort has been committed to establishing physical models to rationalize and predict pH dependence from molecular structures. Two of the key challenges are to accurately calculate ionizable group solvation and hydration and then to apply this modeling to all conformations relevant to the process in question. Explicit solvent methods coupled to molecular dynamics simulation are increasingly complementing lower resolution implicit solvent techniques, but equally, the scale of biological data acquisition leaves a role for high-throughput modeling. Additionally, determination of ranges of structures for a system allows sampling of key stages in solvation. In a review of the area, it is emphasized that pH sensors in biology beyond the most obvious candidate (histidine side chain, with an unshifted pK a near neutral pH) should be considered; that modeling can benefit from other concepts in bioinformatics, in particular modulation of interactions and function in families of homologs; and that it can also be beneficial to incorporate as many experimental structures as possible, to mitigate against small variations in conformation and to analyze larger, functional, conformational changes. These aspects are then demonstrated with new work on the spike protein of SARS-CoV-2, looking at the pH dependence of variants, including prediction of a change in the balance of locked, closed, and open forms at neutral pH for the Omicron variant spike protein.
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Affiliation(s)
- Jim Warwicker
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Institute of Biotechnology, University of Manchester, Manchester, United Kingdom
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14
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Feng B, Zhu Y, Wu J, Huang X, Song R, Huang L, Feng X, Zeng W. Monitoring intracellular pH fluctuation with an excited-state intramolecular proton transfer-based ratiometric fluorescent sensor. CHINESE CHEM LETT 2021. [DOI: 10.1016/j.cclet.2021.03.074] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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15
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Kazyken D, Lentz SI, Fingar DC. Alkaline intracellular pH (pHi) activates AMPK-mTORC2 signaling to promote cell survival during growth factor limitation. J Biol Chem 2021; 297:101100. [PMID: 34418433 PMCID: PMC8479482 DOI: 10.1016/j.jbc.2021.101100] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 08/12/2021] [Accepted: 08/17/2021] [Indexed: 01/12/2023] Open
Abstract
The mechanistic target of rapamycin (mTOR) complex 2 (mTORC2) signaling controls cell metabolism, promotes cell survival, and contributes to tumorigenesis, yet its upstream regulation remains poorly defined. Although considerable evidence supports the prevailing view that amino acids activate mTOR complex 1 but not mTORC2, several studies reported paradoxical activation of mTORC2 signaling by amino acids. We noted that after amino acid starvation of cells in culture, addition of an amino acid solution increased mTORC2 signaling. Interestingly, we found the pH of the amino acid solution to be alkaline, ∼pH 10. These observations led us to discover and demonstrate here that alkaline intracellular pH (pHi) represents a previously unknown activator of mTORC2. Using a fluorescent pH-sensitive dye (cSNARF1-AM) coupled with live-cell imaging, we demonstrate that culturing cells in media at an alkaline pH induces a rapid rise in the pHi, which increases mTORC2 catalytic activity and downstream signaling to the pro-growth and pro-survival kinase Akt. Alkaline pHi also activates AMPK, a canonical sensor of energetic stress. Functionally, alkaline pHi activates AMPK-mTOR signaling, which attenuates apoptosis caused by growth factor withdrawal. Collectively, these findings reveal that alkaline pHi increases mTORC2- and AMPK-mediated signaling to promote cell survival during conditions of growth factor limitation, analogous to the demonstrated ability of energetic stress to activate AMPK–mTORC2 and promote cell survival. As an elevated pHi represents an underappreciated hallmark of cancer cells, we propose that the alkaline pHi stress sensing by AMPK–mTORC2 may contribute to tumorigenesis by enabling cancer cells at the core of a growing tumor to evade apoptosis and survive.
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Affiliation(s)
- D Kazyken
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - S I Lentz
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - D C Fingar
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
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16
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Sesanto R, Kuehn JF, Barber DL, White KA. Low pH Facilitates Heterodimerization of Mutant Isocitrate Dehydrogenase IDH1-R132H and Promotes Production of 2-Hydroxyglutarate. Biochemistry 2021; 60:1983-1994. [PMID: 34143606 PMCID: PMC8246651 DOI: 10.1021/acs.biochem.1c00059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
![]()
Isocitrate dehydrogenase
1 (IDH1) is a key metabolic enzyme for
maintaining cytosolic levels of α-ketoglutarate (AKG) and preserving
the redox environment of the cytosol. Wild-type (WT) IDH1 converts
isocitrate to AKG; however, mutant IDH1-R132H that is recurrent in
human cancers catalyzes the neomorphic production of the oncometabolite d-2-hydroxyglutrate (D-2HG) from AKG. Recent work suggests that
production of l-2-hydroxyglutarte in cancer cells can be
regulated by environmental changes, including hypoxia and intracellular
pH (pHi). However, it is unknown whether and how pHi affects the activity
of IDH1-R132H. Here, we show that in cells IDH1-R132H can produce
D-2HG in a pH-dependent manner with increased production at lower
pHi. We also identify a molecular mechanism by which this pH sensitivity
is achieved. We show that pH-dependent production of D-2HG is mediated
by pH-dependent heterodimer formation between IDH1-WT and IDH1-R132H.
In contrast, neither IDH1-WT nor IDH1-R132H homodimer formation is
affected by pH. Our results demonstrate that robust production of
D-2HG by IDH1-R132H relies on the coincidence of (1) the ability to
form heterodimers with IDH1-WT and (2) low pHi or highly abundant
AKG substrate. These data suggest cancer-associated IDH1-R132H may
be sensitive to physiological or microenvironmental cues that lower
pH, such as hypoxia or metabolic reprogramming. This work reveals
new molecular considerations for targeted therapeutics and suggests
potential synergistic effects of using catalytic IDH1 inhibitors targeting
D-2HG production in combination with drugs targeting the tumor microenvironment.
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Affiliation(s)
- Rae Sesanto
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California 94122, United States
| | - Jessamine F Kuehn
- Department of Chemistry and Biochemistry, The University of Notre Dame, Notre Dame, Indiana 46556, United States.,Harper Cancer Research Institute, South Bend, Indiana 46617, United States
| | - Diane L Barber
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California 94122, United States
| | - Katharine A White
- Department of Chemistry and Biochemistry, The University of Notre Dame, Notre Dame, Indiana 46556, United States.,Harper Cancer Research Institute, South Bend, Indiana 46617, United States
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17
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Manoli SS, Kisor K, Webb BA, Barber DL. Ethyl isopropyl amiloride decreases oxidative phosphorylation and increases mitochondrial fusion in clonal untransformed and cancer cells. Am J Physiol Cell Physiol 2021; 321:C147-C157. [PMID: 34038242 DOI: 10.1152/ajpcell.00001.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Many cancer cells, regardless of their tissue origin or genetic landscape, have increased expression or activity of the plasma membrane Na-H exchanger NHE1 and a higher intracellular pH (pHi) compared with untransformed cells. A current perspective that remains to be validated is that increased NHE1 activity and pHi enable a Warburg-like metabolic reprogramming of increased glycolysis and decreased mitochondrial oxidative phosphorylation. We tested this perspective and find it is not accurate for clonal pancreatic and breast cancer cells. Using the pharmacological reagent ethyl isopropyl amiloride (EIPA) to inhibit NHE1 activity and decrease pHi, we observe no change in glycolysis, as indicated by secreted lactate and intracellular pyruvate, despite confirming increased activity of the glycolytic enzyme phosphofructokinase-1 at higher pH. Also, in contrast to predictions, we find a significant decrease in oxidative phosphorylation with EIPA, as indicated by oxygen consumption rate (OCR). Decreased OCR with EIPA is not associated with changes in pathways that fuel oxidative phosphorylation or with mitochondrial membrane potential but occurs with a change in mitochondrial dynamics that includes a significant increase in elongated mitochondrial networks, suggesting increased fusion. These findings conflict with current paradigms on increased pHi inhibiting oxidative phosphorylation and increased oxidative phosphorylation being associated with mitochondrial fusion. Moreover, these findings raise questions on the suggested use of EIPA-like compounds to limit metabolic reprogramming in cancer cells.
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Affiliation(s)
- Sagar S Manoli
- Department of Cell and Tissue Biology, University of California, San Francisco, California
| | - Kyle Kisor
- Department of Cell and Tissue Biology, University of California, San Francisco, California
| | - Bradley A Webb
- Department of Biochemistry, West Virginia University, Morgantown, West Virginia
| | - Diane L Barber
- Department of Cell and Tissue Biology, University of California, San Francisco, California
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18
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An acidic residue buried in the dimer interface of isocitrate dehydrogenase 1 (IDH1) helps regulate catalysis and pH sensitivity. Biochem J 2021; 477:2999-3018. [PMID: 32729927 DOI: 10.1042/bcj20200311] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 12/19/2022]
Abstract
Isocitrate dehydrogenase 1 (IDH1) catalyzes the reversible NADP+-dependent conversion of isocitrate to α-ketoglutarate (αKG) to provide critical cytosolic substrates and drive NADPH-dependent reactions like lipid biosynthesis and glutathione regeneration. In biochemical studies, the forward reaction is studied at neutral pH, while the reverse reaction is typically characterized in more acidic buffers. This led us to question whether IDH1 catalysis is pH-regulated, which would have functional implications under conditions that alter cellular pH, like apoptosis, hypoxia, cancer, and neurodegenerative diseases. Here, we show evidence of catalytic regulation of IDH1 by pH, identifying a trend of increasing kcat values for αKG production upon increasing pH in the buffers we tested. To understand the molecular determinants of IDH1 pH sensitivity, we used the pHinder algorithm to identify buried ionizable residues predicted to have shifted pKa values. Such residues can serve as pH sensors, with changes in protonation states leading to conformational changes that regulate catalysis. We identified an acidic residue buried at the IDH1 dimer interface, D273, with a predicted pKa value upshifted into the physiological range. D273 point mutations had decreased catalytic efficiency and, importantly, loss of pH-regulated catalysis. Based on these findings, we conclude that IDH1 activity is regulated, at least in part, by pH. We show this regulation is mediated by at least one buried acidic residue ∼12 Å from the IDH1 active site. By establishing mechanisms of regulation of this well-conserved enzyme, we highlight catalytic features that may be susceptible to pH changes caused by cell stress and disease.
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19
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Amiri M, Seidler UE, Nikolovska K. The Role of pH i in Intestinal Epithelial Proliferation-Transport Mechanisms, Regulatory Pathways, and Consequences. Front Cell Dev Biol 2021; 9:618135. [PMID: 33553180 PMCID: PMC7862550 DOI: 10.3389/fcell.2021.618135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/04/2021] [Indexed: 01/07/2023] Open
Abstract
During the maturation of intestinal epithelial cells along the crypt/surface axis, a multitude of acid/base transporters are differentially expressed in their apical and basolateral membranes, enabling processes of electrolyte, macromolecule, nutrient, acid/base and fluid secretion, and absorption. An intracellular pH (pHi)-gradient is generated along the epithelial crypt/surface axis, either as a consequence of the sum of the ion transport activities or as a distinctly regulated entity. While the role of pHi on proliferation, migration, and tumorigenesis has been explored in cancer cells for some time, emerging evidence suggests an important role of the pHi in the intestinal stem cells (ISCs) proliferative rate under physiological conditions. The present review highlights the current state of knowledge about the potential regulatory role of pHi on intestinal proliferation and differentiation.
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20
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Koch LM, Birkeland ES, Battaglioni S, Helle X, Meerang M, Hiltbrunner S, Ibáñez AJ, Peter M, Curioni-Fontecedro A, Opitz I, Dechant R. Cytosolic pH regulates proliferation and tumour growth by promoting expression of cyclin D1. Nat Metab 2020; 2:1212-1222. [PMID: 33077976 DOI: 10.1038/s42255-020-00297-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 09/10/2020] [Indexed: 01/03/2023]
Abstract
Enhanced growth and proliferation of cancer cells are accompanied by profound changes in cellular metabolism. These metabolic changes are also common under physiological conditions, and include increased glucose fermentation accompanied by elevated cytosolic pH (pHc)1,2. However, how these changes contribute to enhanced cell growth and proliferation is unclear. Here, we show that elevated pHc specifically orchestrates an E2F-dependent transcriptional programme to drive cell proliferation by promoting cyclin D1 expression. pHc-dependent transcription of cyclin D1 requires the transcription factors CREB1, ATF1 and ETS1, and the histone acetyltransferases p300 and CBP. Biochemical characterization revealed that the CREB1-p300/CBP interaction acts as a pH sensor and coincidence detector, integrating different mitotic signals to regulate cyclin D1 transcription. We also show that elevated pHc contributes to increased cyclin D1 expression in malignant pleural mesotheliomas (MPMs), and renders these cells hypersensitive to pharmacological reduction of pHc. Taken together, these data demonstrate that elevated pHc is a critical cellular signal regulating G1 progression, and provide a mechanism linking elevated pHc to oncogenic activation of cyclin D1 in MPMs, and possibly other cyclin D1~dependent tumours. Thus, an increase of pHc may represent a functionally important, early event in the aetiology of cancer that is amenable to therapeutic intervention.
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Affiliation(s)
- Lisa Maria Koch
- Institute of Biochemistry, Department of Biology, ETH Zurich, Zurich, Switzerland
- Life science Zürich, PhD program for Molecular Life Sciences, Zurich, Switzerland
| | - Eivind Salmorin Birkeland
- Institute of Biochemistry, Department of Biology, ETH Zurich, Zurich, Switzerland
- Life science Zürich, PhD program for Molecular Life Sciences, Zurich, Switzerland
| | - Stefania Battaglioni
- Institute of Biochemistry, Department of Biology, ETH Zurich, Zurich, Switzerland
- Biozentrum, University of Basel, Basel, Switzerland
| | - Xiao Helle
- Institute of Biochemistry, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Mayura Meerang
- Department of Thoracic Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Stefanie Hiltbrunner
- Department of Medical Oncology and Hematology, University Hospital Zurich, Comprehensive Cancer Center Zurich, University of Zurich, Zurich, Switzerland
| | - Alfredo J Ibáñez
- Core facility for Omics Research and Applied Biotechnology (ICOBA), Pontificia Universidad Católica del Perú, Lima, Peru
| | - Matthias Peter
- Institute of Biochemistry, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Alessandra Curioni-Fontecedro
- Department of Medical Oncology and Hematology, University Hospital Zurich, Comprehensive Cancer Center Zurich, University of Zurich, Zurich, Switzerland
| | - Isabelle Opitz
- Department of Thoracic Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Reinhard Dechant
- Institute of Biochemistry, Department of Biology, ETH Zurich, Zurich, Switzerland.
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21
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Cancer and pH Dynamics: Transcriptional Regulation, Proteostasis, and the Need for New Molecular Tools. Cancers (Basel) 2020; 12:cancers12102760. [PMID: 32992762 PMCID: PMC7601256 DOI: 10.3390/cancers12102760] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 09/18/2020] [Accepted: 09/21/2020] [Indexed: 12/11/2022] Open
Abstract
An emerging hallmark of cancer cells is dysregulated pH dynamics. Recent work has suggested that dysregulated intracellular pH (pHi) dynamics enable diverse cancer cellular behaviors at the population level, including cell proliferation, cell migration and metastasis, evasion of apoptosis, and metabolic adaptation. However, the molecular mechanisms driving pH-dependent cancer-associated cell behaviors are largely unknown. In this review article, we explore recent literature suggesting pHi dynamics may play a causative role in regulating or reinforcing tumorigenic transcriptional and proteostatic changes at the molecular level, and discuss outcomes on tumorigenesis and tumor heterogeneity. Most of the data we discuss are population-level analyses; lack of single-cell data is driven by a lack of tools to experimentally change pHi with spatiotemporal control. Data is also sparse on how pHi dynamics play out in complex in vivo microenvironments. To address this need, at the end of this review, we cover recent advances for live-cell pHi measurement at single-cell resolution. We also discuss the essential role for tool development in revealing mechanisms by which pHi dynamics drive tumor initiation, progression, and metastasis.
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22
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Liu Y, White KA, Barber DL. Intracellular pH Regulates Cancer and Stem Cell Behaviors: A Protein Dynamics Perspective. Front Oncol 2020; 10:1401. [PMID: 32983969 PMCID: PMC7479815 DOI: 10.3389/fonc.2020.01401] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 07/02/2020] [Indexed: 12/12/2022] Open
Abstract
The International Society of Cancer Metabolism (ISCaM) meeting on Cancer Metabolic Rewiring, held in Braga Portugal in October 2019, provided an outstanding forum for investigators to present current findings and views, and discuss ideas and future directions on fundamental biology as well as clinical translations. The first session on Cancer pH Dynamics was preceded by the opening keynote presentation from our group entitled Intracellular pH Regulation of Protein Dynamics: From Cancer to Stem Cell Behaviors. In this review we introduce a brief background on intracellular pH (pHi) dynamics, including how it is regulated as well as functional consequences, summarize key findings included in our presentation, and conclude with perspectives on how understanding the role of pHi dynamics in stem cells can be relevant for understanding how pHi dynamics enables cancer progression.
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Affiliation(s)
- Yi Liu
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, United States
| | - Katharine A White
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, United States
| | - Diane L Barber
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, United States
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23
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Oginuma M, Harima Y, Tarazona OA, Diaz-Cuadros M, Michaut A, Ishitani T, Xiong F, Pourquié O. Intracellular pH controls WNT downstream of glycolysis in amniote embryos. Nature 2020; 584:98-101. [PMID: 32581357 PMCID: PMC8278564 DOI: 10.1038/s41586-020-2428-0] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 04/02/2020] [Indexed: 02/04/2023]
Abstract
Formation of the body of vertebrate embryos proceeds sequentially by posterior addition of tissues from the tail bud. Cells of the tail bud and the posterior presomitic mesoderm, which control posterior elongation1, exhibit a high level of aerobic glycolysis that is reminiscent of the metabolic status of cancer cells experiencing the Warburg effect2,3. Glycolytic activity downstream of fibroblast growth factor controls WNT signalling in the tail bud3. In the neuromesodermal precursors of the tail bud4, WNT signalling promotes the mesodermal fate that is required for sustained axial elongation, at the expense of the neural fate3,5. How glycolysis regulates WNT signalling in the tail bud is currently unknown. Here we used chicken embryos and human tail bud-like cells differentiated in vitro from induced pluripotent stem cells to show that these cells exhibit an inverted pH gradient, with the extracellular pH lower than the intracellular pH, as observed in cancer cells6. Our data suggest that glycolysis increases extrusion of lactate coupled to protons via the monocarboxylate symporters. This contributes to elevating the intracellular pH in these cells, which creates a favourable chemical environment for non-enzymatic β-catenin acetylation downstream of WNT signalling. As acetylated β-catenin promotes mesodermal rather than neural fate7, this ultimately leads to activation of mesodermal transcriptional WNT targets and specification of the paraxial mesoderm in tail bud precursors. Our work supports the notion that some tumour cells reactivate a developmental metabolic programme.
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Affiliation(s)
- Masayuki Oginuma
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA
- IMCR, Gunma University, Gunma, Japan
| | - Yukiko Harima
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA
| | - Oscar A Tarazona
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA
| | - Margarete Diaz-Cuadros
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA
| | - Arthur Michaut
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA
| | - Tohru Ishitani
- IMCR, Gunma University, Gunma, Japan
- RIMD, Osaka University, Osaka, Japan
| | - Fengzhu Xiong
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA
| | - Olivier Pourquié
- Department of Genetics, Harvard Medical School, Boston, MA, USA.
- Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA.
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA.
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24
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Cool CD, Kuebler WM, Bogaard HJ, Spiekerkoetter E, Nicolls MR, Voelkel NF. The hallmarks of severe pulmonary arterial hypertension: the cancer hypothesis-ten years later. Am J Physiol Lung Cell Mol Physiol 2020; 318:L1115-L1130. [PMID: 32023082 PMCID: PMC9847334 DOI: 10.1152/ajplung.00476.2019] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Severe forms of pulmonary arterial hypertension (PAH) are most frequently the consequence of a lumen-obliterating angiopathy. One pathobiological model is that the initial pulmonary vascular endothelial cell injury and apoptosis is followed by the evolution of phenotypically altered, apoptosis-resistant, proliferating cells and an inflammatory vascular immune response. Although there may be a vasoconstrictive disease component, the increased pulmonary vascular shear stress in established PAH is caused largely by the vascular wall pathology. In this review, we revisit the "quasi-malignancy concept" of severe PAH and examine to what extent the hallmarks of PAH can be compared with the hallmarks of cancer. The cancer model of severe PAH, based on the growth of abnormal vascular and bone marrow-derived cells, may enable the emergence of novel cell-based PAH treatment strategies.
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Affiliation(s)
- Carlyne D. Cool
- 1Department of Pathology, University of Colorado,
Anschuetz Campus, Aurora, Colorado
| | | | - Harm Jan Bogaard
- 3Amsterdam University Medical Centers, Department of Pulmonary Medicine, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Edda Spiekerkoetter
- 4Division of Pulmonary and Critical Care Medicine, Stanford University, Palo Alto, California
| | - Mark R. Nicolls
- 4Division of Pulmonary and Critical Care Medicine, Stanford University, Palo Alto, California
| | - Norbert F. Voelkel
- 3Amsterdam University Medical Centers, Department of Pulmonary Medicine, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
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25
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Abstract
Metabolism is a continuous source of acids. To keep up with a desired metabolic rate, tumors must establish an adequate means of clearing their acidic end-products. This homeostatic priority is achieved by various buffers, enzymes, and transporters connected through the common denominator of H+ ions. Whilst this complexity is proportionate to the importance of adequate pH control, it is problematic for developing an intuition for tracking the route taken by acids, assessing the relative importance of various acid-handling proteins, and predicting the outcomes of pharmacological inhibition or genetic alteration. Here, with the help of a simplified mathematical framework, the genesis of cancer pH regulation is explained in terms of the obstacles to efficient acid venting and how these are overcome by specific molecules, often associated with cancer. Ultimately, the pH regulatory apparatus in tumors must (i) provide adequate lactic acid permeability through membranes, (ii) facilitate CO2/HCO3−/H+ diffusivity across the interstitium, (iii) invest in a form of active transport that strikes a favorable balance between intracellular pH and intracellular lactate retention under the energetic constraints of a cell, and (iv) enable the necessary feedback to complete the homeostatic loop. A more informed and quantitative approach to understanding acid-handling in cancer is mandatory for identifying vulnerabilities, which could be exploited as therapeutic targets.
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Affiliation(s)
- Pawel Swietach
- Department of Physiology, Anatomy and Genetics, Parks Road, Oxford, OX1 3PT, England.
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26
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Abstract
An unresolved question critical for understanding cancer is how recurring somatic mutations are retained and how selective pressures drive retention. Increased intracellular pH (pHi) is common to most cancers and is an early event in cancer development. Recent work shows that recurrent somatic mutations can confer an adaptive gain in pH sensing to mutant proteins, enhancing tumorigenic phenotypes specifically at the increased pHi of cancer. Newly identified amino acid mutation signatures in cancer suggest charge-changing mutations define and shape the mutational landscape of cancer. Taken together, these results support a new perspective on the functional significance of somatic mutations in cancer. In this review, we explore existing data and new directions for better understanding how changes in dynamic pH sensing by somatic mutation might be conferring a fitness advantage to the high pH of cancer.
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27
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Protein Phosphatase 2A Inhibiting β-Catenin Phosphorylation Contributes Critically to the Anti-renal Interstitial Fibrotic Effect of Norcantharidin. Inflammation 2020; 43:878-891. [DOI: 10.1007/s10753-019-01173-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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28
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Keurhorst D, Liashkovich I, Frontzek F, Nitzlaff S, Hofschröer V, Dreier R, Stock C. MMP3 activity rather than cortical stiffness determines NHE1-dependent invasiveness of melanoma cells. Cancer Cell Int 2019; 19:285. [PMID: 31728131 PMCID: PMC6842528 DOI: 10.1186/s12935-019-1015-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 11/01/2019] [Indexed: 12/31/2022] Open
Abstract
Background Both cell adhesion and matrix metalloproteinase (MMP) activity depend on pH at the cell surface. By regulating extracellular juxtamembrane pH, the Na+/H+ exchanger NHE1 plays a significant part in human melanoma (MV3) cell migration and invasion. Because NHE1, besides its pH-regulatory transport function, also serves as a structural element tying the cortical actin cytoskeleton to the plasma membrane, we investigated whether NHE1 affects cortical stiffness of MV3 cells, and how this makes an impact on their invasiveness. Methods NHE1 overexpressing MV3 cells were compared to the corresponding mock-transfected control cells. NHE1 expression was verified by Western blotting, cariporide (HOE642) was used to inhibit NHE1 activity, cell stiffness was determined by atomic force microscopy, and F-actin was visualized by phalloidin-staining. Migration on, and invasion of, native and glutaraldehyde-fixed collagen I substrates were analyzed using time-lapse video microscopy and Boyden-chamber assays, respectively. MMP secretion and activity were detected by Western blot and zymography, respectively. MMP activity was inhibited with NNGH. Results The cortical, but not the bulk stiffness, was significantly higher in NHE1 overexpressing cells. This increase in cortical stiffness was accompanied by a reorganization of the cortical cytoskeleton, i.e. a condensation of F-actin underneath and along the plasma membrane. However, it was not affected by NHE1 inhibition. Nevertheless, actin dynamics is required for cell invasion as demonstrated with the application of cytochalasin D. NHE1 overexpression was associated with an elevated MMP3 secretion and an increase in the invasion of a native matrix. This increase in invasiveness could be antagonized by the MMP inhibitor NNGH. Transmigration through a glutaraldehyde-fixed, indigestible substrate was not affected by NHE1 overexpression. Conclusion NHE1, as a structural element and independently of its transport activity, contributes to the organization of the cortical F-actin meshwork and thus impacts cortical stiffness. Since NHE1 overexpression stimulates MMP3 secretion but does not change transmigration through a fixed substrate, MV3 cell invasion of a native substrate depends on MMP activity rather than on a modifiable cortical stiffness.
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Affiliation(s)
- Dennis Keurhorst
- 1Institute of Physiology II, University of Münster, Robert-Koch-Str. 27b, 48149 Münster, Germany
| | - Ivan Liashkovich
- 1Institute of Physiology II, University of Münster, Robert-Koch-Str. 27b, 48149 Münster, Germany
| | - Fabian Frontzek
- 2Department of Oncology and Hematology, University Hospital of Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany
| | - Svenja Nitzlaff
- 3Institute of Animal Physiology, University of Münster, Schlossplatz 8, 48143 Münster, Germany
| | - Verena Hofschröer
- 1Institute of Physiology II, University of Münster, Robert-Koch-Str. 27b, 48149 Münster, Germany
| | - Rita Dreier
- 4Institute of Physiological Chemistry and Pathobiochemistry, University of Münster, Waldeyer-Str. 15, 48149 Münster, Germany
| | - Christian Stock
- 1Institute of Physiology II, University of Münster, Robert-Koch-Str. 27b, 48149 Münster, Germany.,5Department of Gastroenterology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
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29
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Walton ZE, Brooks RC, Dang CV. mTOR Senses Intracellular pH through Lysosome Dispersion from RHEB. Bioessays 2019; 41:e1800265. [PMID: 31157925 PMCID: PMC6730656 DOI: 10.1002/bies.201800265] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/18/2019] [Indexed: 02/04/2023]
Abstract
Acidity, generated in hypoxia or hypermetabolic states, perturbs homeostasis and is a feature of solid tumors. That acid peripherally disperses lysosomes is a three-decade-old observation, yet one little understood or appreciated. However, recent work has recognized the inhibitory impact this spatial redistribution has on mechanistic target of rapamycin complex 1 (mTORC1), a key regulator of metabolism. This finding argues for a paradigm shift in localization of mTORC1 activator Ras homolog enriched in brain (RHEB), a conclusion several others have now independently reached. Thus, mTORC1, known to sense amino acids, mitogens, and energy to restrict biosynthesis to times of adequate resources, also senses pH and, via dampened mTOR-governed synthesis of clock proteins, regulates the circadian clock to achieve concerted responses to metabolic stress. While this may allow cancer to endure metabolic deprivation, immune cell mTOR signaling likewise exhibits pH sensitivity, suggesting that suppression of antitumor immune function by solid tumor acidity may additionally fuel cancers, an obstacle potentially reversible through therapeutic pH manipulation.
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Affiliation(s)
| | | | - Chi V. Dang
- Ludwig Institute for Cancer Research, New York, NY 10017
- The Wistar Institute, Philadelphia, PA 19104
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30
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Benitez M, Tatapudy S, Liu Y, Barber DL, Nystul TG. Drosophila anion exchanger 2 is required for proper ovary development and oogenesis. Dev Biol 2019; 452:127-133. [PMID: 31071312 DOI: 10.1016/j.ydbio.2019.04.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 03/22/2019] [Accepted: 04/26/2019] [Indexed: 02/06/2023]
Abstract
Understanding how cell fate decisions are regulated is a central question in stem cell biology. Recent studies have demonstrated that intracellular pH (pHi) dynamics contribute to this process. Indeed, the pHi of cells within a tissue is not simply a consequence of chemical reactions in the cytoplasm and other cellular activity, but is actively maintained at a specific setpoint in each cell type. We found previously that the pHi of cells in the follicle stem cell (FSC) lineage in the Drosophila ovary increases progressively during differentiation from an average of 6.8 in the FSCs, to 7.0 in newly produced daughter cells, to 7.3 in more differentiated cells. Two major regulators of pHi in this lineage are Drosophila sodium-proton exchanger 2 (dNhe2) and a previously uncharacterized gene, CG8177, that is homologous to mammalian anion exchanger 2 (AE2). Based on this homology, we named the gene anion exchanger 2 (ae2). Here, we generated null alleles of ae2 and found that homozygous mutant flies are viable but have severe defects in ovary development and adult oogenesis. Specifically, we find that ae2 null flies have smaller ovaries, reduced fertility, and impaired follicle formation. In addition, we find that the follicle formation defect can be suppressed by a decrease in dNhe2 copy number and enhanced by the overexpression of dNhe2, suggesting that this phenotype is due to the dysregulation of pHi. These findings support the emerging idea that pHi dynamics regulate cell fate decisions and our studies provide new genetic tools to investigate the mechanisms by which this occurs.
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Affiliation(s)
- Marimar Benitez
- Departments of Anatomy and OB-GYN/RS, University of California, San Francisco, USA
| | - Sumitra Tatapudy
- Departments of Anatomy and OB-GYN/RS, University of California, San Francisco, USA
| | - Yi Liu
- Departments of Anatomy and OB-GYN/RS, University of California, San Francisco, USA
| | - Diane L Barber
- Department of Cell and Tissue Biology, University of California, San Francisco, USA
| | - Todd G Nystul
- Departments of Anatomy and OB-GYN/RS, University of California, San Francisco, USA.
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31
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Charafeddine RA, Cortopassi WA, Lak P, Tan R, McKenney RJ, Jacobson MP, Barber DL, Wittmann T. Tau repeat regions contain conserved histidine residues that modulate microtubule-binding in response to changes in pH. J Biol Chem 2019; 294:8779-8790. [PMID: 30992364 DOI: 10.1074/jbc.ra118.007004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 04/13/2019] [Indexed: 12/20/2022] Open
Abstract
Tau, a member of the MAP2/tau family of microtubule-associated proteins, stabilizes and organizes axonal microtubules in healthy neurons. In neurodegenerative tauopathies, tau dissociates from microtubules and forms neurotoxic extracellular aggregates. MAP2/tau family proteins are characterized by three to five conserved, intrinsically disordered repeat regions that mediate electrostatic interactions with the microtubule surface. Here, we used molecular dynamics, microtubule-binding experiments, and live-cell microscopy, revealing that highly-conserved histidine residues near the C terminus of each microtubule-binding repeat are pH sensors that can modulate tau-microtubule interaction strength within the physiological intracellular pH range. We observed that at low pH (<7.5), these histidines are positively charged and interact with phenylalanine residues in a hydrophobic cleft between adjacent tubulin dimers. At higher pH (>7.5), tau deprotonation decreased binding to microtubules both in vitro and in cells. Electrostatic and hydrophobic characteristics of histidine were both required for tau-microtubule binding, as substitutions with constitutively and positively charged nonaromatic lysine or uncharged alanine greatly reduced or abolished tau-microtubule binding. Consistent with these findings, tau-microtubule binding was reduced in a cancer cell model with increased intracellular pH but was rapidly restored by decreasing the pH to normal levels. These results add detailed insights into the intracellular regulation of tau activity that may be relevant in both normal and pathological conditions.
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Affiliation(s)
- Rabab A Charafeddine
- From the Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California 94143
| | - Wilian A Cortopassi
- the Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California 94158, and
| | - Parnian Lak
- the Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California 94158, and
| | - Ruensern Tan
- the Department of Molecular and Cellular Biology, University of California Davis, Davis, California 95616
| | - Richard J McKenney
- the Department of Molecular and Cellular Biology, University of California Davis, Davis, California 95616
| | - Matthew P Jacobson
- the Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California 94158, and
| | - Diane L Barber
- From the Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California 94143
| | - Torsten Wittmann
- From the Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California 94143,
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32
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Grillo-Hill BK, White KA. Oncogenic β-catenin mutations evade pH-regulated degradation. Mol Cell Oncol 2019; 6:1554470. [PMID: 30788422 PMCID: PMC6370367 DOI: 10.1080/23723556.2018.1554470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 11/25/2018] [Accepted: 11/28/2018] [Indexed: 02/04/2023]
Abstract
β-catenin has roles in cell-cell adhesion and Wnt signaling. We recently showed that β-catenin protein abundance is decreased at higher intracellular pH (pHi), mediated by pH-sensitive interaction with the beta-transducin repeat containing E3 ubiquitin protein ligase (β-TrCP). Increased pHi facilitates β-TrCP binding and degradation of β-catenin. β-catenin mutations that abrogate the pH-sensitive interaction induce significant tumors not seen with other β-catenin stabilizing mutants.
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Affiliation(s)
- Bree K Grillo-Hill
- Department of Biological Sciences, San Jose State University, San Jose, CA, USA
| | - Katharine A White
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, USA.,Department of Chemistry and Biochemistry, Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, USA
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Wang DY, Gendoo DMA, Ben-David Y, Woodgett JR, Zacksenhaus E. A subgroup of microRNAs defines PTEN-deficient, triple-negative breast cancer patients with poorest prognosis and alterations in RB1, MYC, and Wnt signaling. Breast Cancer Res 2019; 21:18. [PMID: 30704524 PMCID: PMC6357448 DOI: 10.1186/s13058-019-1098-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 01/10/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Triple-negative breast cancer (TNBC) represents a heterogeneous group of ER- and HER2-negative tumors with poor clinical outcome. We recently reported that Pten-loss cooperates with low expression of microRNA-145 to induce aggressive TNBC-like lesions in mice. To systematically identify microRNAs that cooperate with PTEN-loss to induce aggressive human BC, we screened for miRNAs whose expression correlated with PTEN mRNA levels and determined the prognostic power of each PTEN-miRNA pair alone and in combination with other miRs. METHODS Publically available data sets with mRNA, microRNA, genomics, and clinical outcome were interrogated to identify miRs that correlate with PTEN expression and predict poor clinical outcome. Alterations in genomic landscape and signaling pathways were identified in most aggressive TNBC subgroups. Connectivity mapping was used to predict response to therapy. RESULTS In TNBC, PTEN loss cooperated with reduced expression of hsa-miR-4324, hsa-miR-125b, hsa-miR-381, hsa-miR-145, and has-miR136, all previously implicated in metastasis, to predict poor prognosis. A subgroup of TNBC patients with PTEN-low and reduced expression of four or five of these miRs exhibited the worst clinical outcome relative to other TNBCs (hazard ratio (HR) = 3.91; P < 0.0001), and this was validated on an independent cohort (HR = 4.42; P = 0.0003). The PTEN-low/miR-low subgroup showed distinct oncogenic alterations as well as TP53 mutation, high RB1-loss signature and high MYC, PI3K, and β-catenin signaling. This lethal subgroup almost completely overlapped with TNBC patients selected on the basis of Pten-low and RB1 signature loss or β-catenin signaling-high. Connectivity mapping predicted response to inhibitors of the PI3K pathway. CONCLUSIONS This analysis identified microRNAs that define a subclass of highly lethal TNBCs that should be prioritized for aggressive therapy.
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Affiliation(s)
- Dong-Yu Wang
- Toronto General Research Institute - University Health Network, 67 College Street, Rm. 407, Toronto, Ontario M5G 2M1 Canada
| | - Deena M. A. Gendoo
- Centre for Computational Biology, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
| | - Yaacov Ben-David
- The Key laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guiyang, 550014 Guizhou China
- State Key Laboratory for Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550025 China
| | - James R. Woodgett
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 600 University Avenue, Toronto, ON Canada
| | - Eldad Zacksenhaus
- Toronto General Research Institute - University Health Network, 67 College Street, Rm. 407, Toronto, Ontario M5G 2M1 Canada
- Department of Medicine, University of Toronto, Toronto, Ontario Canada
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