1
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Han C, Gu Y, Miao R, Han W, Zhang Q, Hu X, Li H, Zhang Y, Chen M. DLPC induces ferroptosis in cancer cells. Acta Biochim Biophys Sin (Shanghai) 2024. [PMID: 38932700 DOI: 10.3724/abbs.2024097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2024] Open
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2
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Glotzbach A, Rohlf K, Gonscharow A, Lüke S, Demirci Ö, Begher-Tibbe B, Overbeck N, Reinders J, Cadenas C, Hengstler JG, Edlund K, Marchan R. EDI3 knockdown in ER-HER2+ breast cancer cells reduces tumor burden and improves survival in two mouse models of experimental metastasis. Breast Cancer Res 2024; 26:87. [PMID: 38816770 PMCID: PMC11138102 DOI: 10.1186/s13058-024-01849-y] [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: 11/02/2023] [Accepted: 05/23/2024] [Indexed: 06/01/2024] Open
Abstract
BACKGROUND Despite progress understanding the mechanisms underlying tumor spread, metastasis remains a clinical challenge. We identified the choline-producing glycerophosphodiesterase, EDI3 and reported its association with metastasis-free survival in endometrial cancer. We also observed that silencing EDI3 slowed cell migration and other cancer-relevant phenotypes in vitro. Recent work demonstrated high EDI3 expression in ER-HER2+ breast cancer compared to the other molecular subtypes. Silencing EDI3 in ER-HER2+ cells significantly reduced cell survival in vitro and decreased tumor growth in vivo. However, a role for EDI3 in tumor metastasis in this breast cancer subtype was not explored. Therefore, in the present work we investigate whether silencing EDI3 in ER-HER2+ breast cancer cell lines alters phenotypes linked to metastasis in vitro, and metastasis formation in vivo using mouse models of experimental metastasis. METHODS To inducibly silence EDI3, luciferase-expressing HCC1954 cells were transduced with lentiviral particles containing shRNA oligos targeting EDI3 under the control of doxycycline. The effect on cell migration, adhesion, colony formation and anoikis was determined in vitro, and significant findings were confirmed in a second ER-HER2+ cell line, SUM190PT. Doxycycline-induced HCC1954-luc shEDI3 cells were injected into the tail vein or peritoneum of immunodeficient mice to generate lung and peritoneal metastases, respectively and monitored using non-invasive bioluminescence imaging. Metabolite levels in cells and tumor tissue were analyzed using targeted mass spectrometry and MALDI mass spectrometry imaging (MALDI-MSI), respectively. RESULTS Inducibly silencing EDI3 reduced cell adhesion and colony formation, as well as increased susceptibility to anoikis in HCC1954-luc cells, which was confirmed in SUM190PT cells. No influence on cell migration was observed. Reduced luminescence was seen in lungs and peritoneum of mice injected with cells expressing less EDI3 after tail vein and intraperitoneal injection, respectively, indicative of reduced metastasis. Importantly, mice injected with EDI3-silenced cells survived longer. Closer analysis of the peritoneal organs revealed that silencing EDI3 had no effect on metastatic organotropism but instead reduced metastatic burden. Finally, metabolic analyses revealed significant changes in choline and glycerophospholipid metabolites in cells and in pancreatic metastases in vivo. CONCLUSIONS Reduced metastasis upon silencing supports EDI3's potential as a treatment target in metastasizing ER-HER2+ breast cancer.
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Affiliation(s)
- Annika Glotzbach
- Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund (IfADo), Ardeystrasse 67, 44139, Dortmund, Germany
| | - Katharina Rohlf
- Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund (IfADo), Ardeystrasse 67, 44139, Dortmund, Germany
| | - Anastasia Gonscharow
- Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund (IfADo), Ardeystrasse 67, 44139, Dortmund, Germany
| | - Simon Lüke
- Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund (IfADo), Ardeystrasse 67, 44139, Dortmund, Germany
| | - Özlem Demirci
- Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund (IfADo), Ardeystrasse 67, 44139, Dortmund, Germany
- Department of Biology, Science Faculty, Dicle University, Diyarbakir, Turkey
| | - Brigitte Begher-Tibbe
- Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund (IfADo), Ardeystrasse 67, 44139, Dortmund, Germany
| | - Nina Overbeck
- Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund (IfADo), Ardeystrasse 67, 44139, Dortmund, Germany
| | - Jörg Reinders
- Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund (IfADo), Ardeystrasse 67, 44139, Dortmund, Germany
| | - Cristina Cadenas
- Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund (IfADo), Ardeystrasse 67, 44139, Dortmund, Germany
| | - Jan G Hengstler
- Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund (IfADo), Ardeystrasse 67, 44139, Dortmund, Germany
| | - Karolina Edlund
- Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund (IfADo), Ardeystrasse 67, 44139, Dortmund, Germany
| | - Rosemarie Marchan
- Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund (IfADo), Ardeystrasse 67, 44139, Dortmund, Germany.
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3
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McPhee M, Lee J, Salsman J, Pinelli M, Di Cara F, Rosen K, Dellaire G, Ridgway ND. Nuclear lipid droplets in Caco2 cells originate from nascent precursors and in situ at the nuclear envelope. J Lipid Res 2024; 65:100540. [PMID: 38570093 PMCID: PMC11077042 DOI: 10.1016/j.jlr.2024.100540] [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: 07/11/2023] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 04/05/2024] Open
Abstract
Intestinal epithelial cells convert excess fatty acids into triglyceride (TAG) for storage in cytoplasmic lipid droplets and secretion in chylomicrons. Nuclear lipid droplets (nLDs) are present in intestinal cells but their origin and relationship to cytoplasmic TAG synthesis and secretion is unknown. nLDs and related lipid-associated promyelocytic leukemia structures (LAPS) were abundant in oleate-treated Caco2 but less frequent in other human colorectal cancer cell lines and mouse intestinal organoids. nLDs and LAPS in undifferentiated oleate-treated Caco2 cells harbored the phosphatidate phosphatase Lipin1, its product diacylglycerol, and CTP:phosphocholine cytidylyltransferase (CCT)α. CCTα knockout Caco2 cells had fewer but larger nLDs, indicating a reliance on de novo PC synthesis for assembly. Differentiation of Caco2 cells caused large nLDs and LAPS to form regardless of oleate treatment or CCTα expression. nLDs and LAPS in Caco2 cells did not associate with apoCIII and apoAI and formed dependently of microsomal triglyceride transfer protein expression and activity, indicating they are not derived from endoplasmic reticulum luminal LDs precursors. Instead, undifferentiated Caco2 cells harbored a constitutive pool of nLDs and LAPS in proximity to the nuclear envelope that expanded in size and number with oleate treatment. Inhibition of TAG synthesis did affect the number of nascent nLDs and LAPS but prevented their association with promyelocytic leukemia protein, Lipin1α, and diacylglycerol, which instead accumulated on the nuclear membranes. Thus, nLD and LAPS biogenesis in Caco2 cells is not linked to lipoprotein secretion but involves biogenesis and/or expansion of nascent nLDs by de novo lipid synthesis.
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Affiliation(s)
- Michael McPhee
- Depts of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jonghwa Lee
- Depts of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jayme Salsman
- Depts of Pathology and Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Marinella Pinelli
- Dept of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Francesca Di Cara
- Dept of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Kirill Rosen
- Depts of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Graham Dellaire
- Depts of Pathology and Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
| | - Neale D Ridgway
- Depts of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia, Canada.
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4
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Din ZU, Cui B, Wang C, Zhang X, Mehmood A, Peng F, Liu Q. Crosstalk between lipid metabolism and EMT: emerging mechanisms and cancer therapy. Mol Cell Biochem 2024:10.1007/s11010-024-04995-1. [PMID: 38622439 DOI: 10.1007/s11010-024-04995-1] [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: 11/18/2023] [Accepted: 03/19/2024] [Indexed: 04/17/2024]
Abstract
Lipids are the key component of all membranes composed of a variety of molecules that transduce intracellular signaling and provide energy to the cells in the absence of nutrients. Alteration in lipid metabolism is a major factor for cancer heterogeneity and a newly identified cancer hallmark. Reprogramming of lipid metabolism affects the diverse cancer phenotypes, especially epithelial-mesenchymal transition (EMT). EMT activation is considered to be an essential step for tumor metastasis, which exhibits a crucial role in the biological processes including development, wound healing, and stem cell maintenance, and has been widely reported to contribute pathologically to cancer progression. Altered lipid metabolism triggers EMT and activates multiple EMT-associated oncogenic pathways. Although the role of lipid metabolism-induced EMT in tumorigenesis is an attractive field of research, there are still significant gaps in understanding the underlying mechanisms and the precise contributions of this interplay. Further study is needed to clarify the specific molecular mechanisms driving the crosstalk between lipid metabolism and EMT, as well as to determine the potential therapeutic implications. The increased dependency of tumor cells on lipid metabolism represents a novel therapeutic target, and targeting altered lipid metabolism holds promise as a strategy to suppress EMT and ultimately inhibit metastasis.
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Grants
- 2022YFA1104002 National Key R&D Program of China
- 2022YFA1104002 National Key R&D Program of China
- 2022YFA1104002 National Key R&D Program of China
- 2022YFA1104002 National Key R&D Program of China
- No. 82373096, No. 82273480, No. 82002960, No. 82003141 National Natural Science Foundation of China
- No. 82373096, No. 82273480, No. 82002960, No. 82003141 National Natural Science Foundation of China
- No. 82373096, No. 82273480, No. 82002960, No. 82003141 National Natural Science Foundation of China
- No. 82373096, No. 82273480, No. 82002960, No. 82003141 National Natural Science Foundation of China
- 2023JH2/101600019 to FP Applied Basic Research Planning Project of Liaoning
- 2023JH2/101600019 to FP Applied Basic Research Planning Project of Liaoning
- 2023JH2/101600019 to FP Applied Basic Research Planning Project of Liaoning
- 2023JH2/101600019 to FP Applied Basic Research Planning Project of Liaoning
- 2023RY013 Science and Technology Talent Innovation Support Policy Implementation Program of Dalian-Outstanding young scientific and technological talents
- 2023RY013 Science and Technology Talent Innovation Support Policy Implementation Program of Dalian-Outstanding young scientific and technological talents
- 2023RY013 Science and Technology Talent Innovation Support Policy Implementation Program of Dalian-Outstanding young scientific and technological talents
- 2023RY013 Science and Technology Talent Innovation Support Policy Implementation Program of Dalian-Outstanding young scientific and technological talents
- 2021RQ004 Dalian High-level Talents Innovation Support Program-Young Science and Technology Star
- 2021RQ004 Dalian High-level Talents Innovation Support Program-Young Science and Technology Star
- 2021RQ004 Dalian High-level Talents Innovation Support Program-Young Science and Technology Star
- 2021RQ004 Dalian High-level Talents Innovation Support Program-Young Science and Technology Star
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Affiliation(s)
- Zaheer Ud Din
- Institute of Cancer Stem Cell, Dalian Medical University, 9 Western Section, Lvshun South Street, Lvshunkou District, Dalian, 116044, Liaoning, China
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Institute of Aging Research, Guangdong Medical University, Dongguan, China
| | - Bai Cui
- Institute of Cancer Stem Cell, Dalian Medical University, 9 Western Section, Lvshun South Street, Lvshunkou District, Dalian, 116044, Liaoning, China
- State Key Laboratory of Oncology in South China, Cancer Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Cenxin Wang
- Institute of Cancer Stem Cell, Dalian Medical University, 9 Western Section, Lvshun South Street, Lvshunkou District, Dalian, 116044, Liaoning, China
| | - Xiaoyu Zhang
- Institute of Cancer Stem Cell, Dalian Medical University, 9 Western Section, Lvshun South Street, Lvshunkou District, Dalian, 116044, Liaoning, China
| | - Arshad Mehmood
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, 050000, China
| | - Fei Peng
- Institute of Cancer Stem Cell, Dalian Medical University, 9 Western Section, Lvshun South Street, Lvshunkou District, Dalian, 116044, Liaoning, China.
| | - Quentin Liu
- Institute of Cancer Stem Cell, Dalian Medical University, 9 Western Section, Lvshun South Street, Lvshunkou District, Dalian, 116044, Liaoning, China.
- State Key Laboratory of Oncology in South China, Cancer Center, Sun Yat-Sen University, Guangzhou, 510060, China.
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5
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Dorighello G, McPhee M, Halliday K, Dellaire G, Ridgway N. Differential contributions of phosphotransferases CEPT1 and CHPT1 to phosphatidylcholine homeostasis and lipid droplet biogenesis. J Biol Chem 2023; 299:104578. [PMID: 36871755 PMCID: PMC10166788 DOI: 10.1016/j.jbc.2023.104578] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 02/21/2023] [Accepted: 02/25/2023] [Indexed: 03/06/2023] Open
Abstract
The CDP-choline (Kennedy) pathway culminates with the synthesis of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) by choline/ethanolamine phosphotransferase 1 (CEPT1) in the endoplasmic reticulum (ER), and PC synthesis by choline phosphotransferase 1 (CHPT1) in the Golgi apparatus. Whether the PC and PE synthesized by CEPT1 and CHPT1 in the ER and Golgi apparatus has different cellular functions has not been formally addressed. Here we used CRISPR editing to generate CEPT1-and CHPT1-knockout (KO) U2OS cells to assess the differential contribution of the enzymes to feed-back regulation of nuclear CTP:phosphocholine cytidylyltransferase (CCT)α, the rate-limiting enzyme in PC synthesis, and lipid droplet (LD) biogenesis. We found that CEPT1-KO cells had a 50% and 80% reduction in PC and PE synthesis, respectively, while PC synthesis in CHPT1-KO cells was also reduced by 50%. CEPT1 knockout caused the post-transcriptional induction of CCTα protein expression as well as its dephosphorylation and constitutive localization on the inner nuclear membrane and nucleoplasmic reticulum. This activated CCTα phenotype was prevented by incubating CEPT1-KO cells with PC liposomes to restore end-product inhibition. Additionally, we determined that CEPT1 was in close proximity to cytoplasmic LDs, and CEPT1 knockout resulted in the accumulation of small cytoplasmic LDs, as well as increased nuclear LDs enriched in CCTα. In contrast, CHPT1 knockout had no effect on CCTα regulation or LD biogenesis. Thus, CEPT1 and CHPT1 contribute equally to PC synthesis; however, only PC synthesized by CEPT1 in the ER regulates CCTα and the biogenesis of cytoplasmic and nuclear LDs.
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Affiliation(s)
- Gabriel Dorighello
- Depts of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia Canada B3H4R2
| | - Michael McPhee
- Depts of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia Canada B3H4R2
| | - Katie Halliday
- Depts of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia Canada B3H4R2
| | - Graham Dellaire
- Depts of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia Canada B3H4R2; Depts of Pathology and Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia Canada B3H4R2
| | - NealeD Ridgway
- Depts of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia Canada B3H4R2.
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6
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Lai X, Li Q, Wu F, Lin J, Chen J, Zheng H, Guo L. Epithelial-Mesenchymal Transition and Metabolic Switching in Cancer: Lessons From Somatic Cell Reprogramming. Front Cell Dev Biol 2020; 8:760. [PMID: 32850862 PMCID: PMC7423833 DOI: 10.3389/fcell.2020.00760] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 07/20/2020] [Indexed: 12/12/2022] Open
Abstract
Epithelial-mesenchymal transition (EMT) and its critical roles during cancer progression have long been recognized and extensively reviewed. Recent studies on the generation of induced pluripotent stem cells (iPSCs) have established the connections among EMT, energy metabolism, DNA methylation, and histone modification. Since energy metabolism, DNA methylation, and histone modification are important for cancer development and there are common characteristics between cancer cells and stem cells, it is reasonable to identify mechanisms that have been established during both reprogramming and cancer progression. In the current review, we start from a brief review on EMT and related processes during cancer progression, and then switch to the EMT during somatic cell reprogramming. We summarize the connection between EMT and metabolic switch during reprogramming, and further review the involvements of DNA methylation and cell proliferation. The connections between EMT and mesenchymal-epithelial transition (MET) and cellular aspects including DNA methylation, histone modification and energy metabolism may provide potential new targets for cancer diagnosis and treatment.
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Affiliation(s)
- Xiaowei Lai
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Qian Li
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou, China
| | - Fang Wu
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Jiechun Lin
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou, China
| | - Jiekai Chen
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou, China
| | - Hui Zheng
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou, China
| | - Lin Guo
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou, China
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7
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Yue L, McPhee MJ, Gonzalez K, Charman M, Lee J, Thompson J, Winkler DFH, Cornell RB, Pelech S, Ridgway ND. Differential dephosphorylation of CTP:phosphocholine cytidylyltransferase upon translocation to nuclear membranes and lipid droplets. Mol Biol Cell 2020; 31:1047-1059. [PMID: 32186954 PMCID: PMC7346725 DOI: 10.1091/mbc.e20-01-0014] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
CTP:phosphocholine cytidylyltransferase-alpha (CCTα) and CCTβ catalyze the rate-limiting step in phosphatidylcholine (PC) biosynthesis. CCTα is activated by association of its α-helical M-domain with nuclear membranes, which is negatively regulated by phosphorylation of the adjacent P-domain. To understand how phosphorylation regulates CCT activity, we developed phosphosite-specific antibodies for pS319 and pY359+pS362 at the N- and C-termini of the P-domain, respectively. Oleate treatment of cultured cells triggered CCTα translocation to the nuclear envelope (NE) and nuclear lipid droplets (nLDs) and rapid dephosphorylation of pS319. Removal of oleate led to dissociation of CCTα from the NE and increased phosphorylation of S319. Choline depletion of cells also caused CCTα translocation to the NE and S319 dephosphorylation. In contrast, Y359 and S362 were constitutively phosphorylated during oleate addition and removal, and CCTα-pY359+pS362 translocated to the NE and nLDs of oleate-treated cells. Mutagenesis revealed that phosphorylation of S319 is regulated independently of Y359+S362, and that CCTα-S315D+S319D was defective in localization to the NE. We conclude that the P-domain undergoes negative charge polarization due to dephosphorylation of S319 and possibly other proline-directed sites and retention of Y359 and S362 phosphorylation, and that dephosphorylation of S319 and S315 is involved in CCTα recruitment to nuclear membranes.
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Affiliation(s)
- Lambert Yue
- Department of Medicine, Division of Neurology, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Michael J McPhee
- Department of Pediatrics and Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Kevin Gonzalez
- Department of Medicine, Division of Neurology, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Mark Charman
- Department of Pediatrics and Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Jonghwa Lee
- Department of Pediatrics and Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Jordan Thompson
- Department of Pediatrics and Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Dirk F H Winkler
- Kinexus Bioinformatics Corporation, Vancouver, BC V6P 6T3, Canada
| | - Rosemary B Cornell
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Steven Pelech
- Department of Medicine, Division of Neurology, University of British Columbia, Vancouver, BC V6T 2B5, Canada.,Kinexus Bioinformatics Corporation, Vancouver, BC V6P 6T3, Canada
| | - Neale D Ridgway
- Department of Pediatrics and Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
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8
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Yang J, Zhang Z, Zhao Y, Cheng J, Zhao C, Wang Z. CCT α is a novel biomarker for diagnosis of laryngeal squamous cell cancer. Sci Rep 2019; 9:11823. [PMID: 31413263 PMCID: PMC6694151 DOI: 10.1038/s41598-019-47895-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 06/18/2019] [Indexed: 12/20/2022] Open
Abstract
Choline phosphate-based delivery systems can target the acidic tumor microenvironment. In this study, we set out to evaluate the diagnostic value of Choline phosphate cytidylyltransferase-α (CCTα) in laryngeal squamous cell cancer (LSCC). The expression of CCTα was detected using immunohistochemistry in 50 LSCC patients’ tissues and 16 vocal polyps as control group. Then, clinical data was collected and we used receiver operating characteristic curve (ROC) to estimate the potential of CCTα as diagnostic biomarker. We found CCTα levels to be significantly high in the tissues derived from LSCC patients, (p < 0.001). Further, we observed a positive correlation of CCTα with tumor size (p < 0.001), TNM stage (p < 0.001), lymph node metastasis (p < 0.001) as well as the grade of LSCC malignancy (p < 0.001). Furthermore, AUC was determined to be 0.939 by ROC, and the optimal cutoff value 3.100, with 76.0% sensitivity and 100% specificity. We also found an epigenetic basis of CCTα over-expression in LSCC tissues with significantly reduced methylation of CCTα in LSCC tissues, compared to vocal polyps (p < 0.001). These results support epigenetically-induced over-expression of CCTα as a potential diagnostic marker for LSCC.
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Affiliation(s)
- Jingpu Yang
- Department of Otolaryngology-Head and Neck Surgery, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun, 130041, China
| | - Zhuping Zhang
- Department of Otolaryngology-Head and Neck Surgery, The Central Hospital of Wuhan, 26 Shengli Street, Wuhan, 430014, China
| | - Yin Zhao
- Department of Otolaryngology-Head and Neck Surgery, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun, 130041, China
| | - Jinzhang Cheng
- Department of Otolaryngology-Head and Neck Surgery, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun, 130041, China
| | - Chang Zhao
- Department of Otolaryngology-Head and Neck Surgery, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun, 130041, China
| | - Zonggui Wang
- Department of Otolaryngology-Head and Neck Surgery, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun, 130041, China.
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9
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Kang H, Kim H, Lee S, Youn H, Youn B. Role of Metabolic Reprogramming in Epithelial⁻Mesenchymal Transition (EMT). Int J Mol Sci 2019; 20:ijms20082042. [PMID: 31027222 PMCID: PMC6514888 DOI: 10.3390/ijms20082042] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/08/2019] [Accepted: 04/23/2019] [Indexed: 02/07/2023] Open
Abstract
Activation of epithelial–mesenchymal transition (EMT) is thought to be an essential step for cancer metastasis. Tumor cells undergo EMT in response to a diverse range of extra- and intracellular stimulants. Recently, it was reported that metabolic shifts control EMT progression and induce tumor aggressiveness. In this review, we summarize the involvement of altered glucose, lipid, and amino acid metabolic enzyme expression and the underlying molecular mechanisms in EMT induction in tumor cells. Moreover, we propose that metabolic regulation through gene-specific or pharmacological inhibition may suppress EMT and this treatment strategy may be applied to prevent tumor progression and improve anti-tumor therapeutic efficacy. This review presents evidence for the importance of metabolic changes in tumor progression and emphasizes the need for further studies to better understand tumor metabolism.
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Affiliation(s)
- Hyunkoo Kang
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea.
| | - Hyunwoo Kim
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea.
| | - Sungmin Lee
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea.
| | - HyeSook Youn
- Department of Integrative Bioscience and Biotechnology, Sejong University, Seoul 05006, Korea.
| | - BuHyun Youn
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea.
- Department of Biological Sciences, Pusan National University, Busan 46241, Korea.
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10
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Nakamura M, Kumrungsee T, Sakuma T, Yamamoto T, Yanaka N. TALEN-mediated targeted editing of the GDE5 gene suppresses fibroblastic cell proliferation. Biosci Biotechnol Biochem 2017; 81:2164-2167. [PMID: 28934905 DOI: 10.1080/09168451.2017.1373593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In this study, we investigated the physiological function of glycerophosphodiesterase 5 (GDE5) in the proliferation of NIH3T3 fibroblasts. We used transcription activator-like effector nuclease (TALEN) in NIH3T3 cells with an intron targeting-mediated GDE5 gene knockout. The heterozygously GDE5-targeted NIH3T3 fibroblasts were isolated and showed decreased cell proliferation and up-regulation of EGFR mRNA expression, indicating that GDE5 modulates fibroblastic cell proliferation.
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Affiliation(s)
- Minako Nakamura
- a Department of Molecular and Applied Bioscience, Graduate School of Biosphere Science , Hiroshima University , Higashi-Hiroshima , Japan
| | - Thanutchaporn Kumrungsee
- a Department of Molecular and Applied Bioscience, Graduate School of Biosphere Science , Hiroshima University , Higashi-Hiroshima , Japan
| | - Tetsushi Sakuma
- b Department of Mathematical and Life Sciences, Graduate School of Science , Hiroshima University , Hiroshima , Japan
| | - Takashi Yamamoto
- b Department of Mathematical and Life Sciences, Graduate School of Science , Hiroshima University , Hiroshima , Japan
| | - Noriyuki Yanaka
- a Department of Molecular and Applied Bioscience, Graduate School of Biosphere Science , Hiroshima University , Higashi-Hiroshima , Japan
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11
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Xiong J, Wang L, Fei XC, Jiang XF, Zheng Z, Zhao Y, Wang CF, Li B, Chen SJ, Janin A, Gale RP, Zhao WL. MYC is a positive regulator of choline metabolism and impedes mitophagy-dependent necroptosis in diffuse large B-cell lymphoma. Blood Cancer J 2017; 7:e0. [PMID: 28686226 PMCID: PMC5549253 DOI: 10.1038/bcj.2017.61] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 05/19/2017] [Accepted: 06/01/2017] [Indexed: 02/07/2023] Open
Abstract
The activation of oncogenes can reprogram tumor cell metabolism. Here, in diffuse large B-cell lymphoma (DLBCL), serum metabolomic analysis revealed that oncogenic MYC could induce aberrant choline metabolism by transcriptionally activating the key enzyme phosphate cytidylyltransferase 1 choline-α (PCYT1A). In B-lymphoma cells, as a consequence of PCYT1A upregulation, MYC impeded lymphoma cells undergo a mitophagy-dependent necroptosis. In DLBCL patients, overexpression of PCYT1A was in parallel with an increase in tumor MYC, as well as a decrease in serum choline metabolite phosphatidylcholine levels and an International Prognostic Index, indicating intermediate-high or high risk. Both in vitro and in vivo, lipid-lowering alkaloid berberine (BBR) exhibited an anti-lymphoma activity through inhibiting MYC-driven downstream PCYT1A expression and inducing mitophagy-dependent necroptosis. Collectively, PCYT1A was upregulated by MYC, which resulted in the induction of aberrant choline metabolism and the inhibition of B-lymphoma cell necroptosis. Referred as a biomarker for DLBCL progression, PCYT1A can be targeted by BBR, providing a potential lipid-modifying strategy in treating MYC-High lymphoma.
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Affiliation(s)
- J Xiong
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Pôle de Recherches Sino-Français en Science du Vivant et Génomique, Laboratory of Molecular Pathology, Shanghai Rui Jin Hospital, Shanghai, China
| | - L Wang
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Pôle de Recherches Sino-Français en Science du Vivant et Génomique, Laboratory of Molecular Pathology, Shanghai Rui Jin Hospital, Shanghai, China
| | - X-C Fei
- Department of Pathology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - X-F Jiang
- Department of Nuclear Medicine, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Z Zheng
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Pôle de Recherches Sino-Français en Science du Vivant et Génomique, Laboratory of Molecular Pathology, Shanghai Rui Jin Hospital, Shanghai, China
| | - Y Zhao
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Pôle de Recherches Sino-Français en Science du Vivant et Génomique, Laboratory of Molecular Pathology, Shanghai Rui Jin Hospital, Shanghai, China
| | - C-F Wang
- Department of Pathology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - B Li
- Department of Nuclear Medicine, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - S-J Chen
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Pôle de Recherches Sino-Français en Science du Vivant et Génomique, Laboratory of Molecular Pathology, Shanghai Rui Jin Hospital, Shanghai, China
| | - A Janin
- Pôle de Recherches Sino-Français en Science du Vivant et Génomique, Laboratory of Molecular Pathology, Shanghai Rui Jin Hospital, Shanghai, China.,Laboratory of Pathology, Paris Diderot University, U1165 Inserm, Paris, France
| | - R P Gale
- Haematology Research Centre, Division of Experimental Medicine, Department of Medicine, Imperial College London, London, UK
| | - W-L Zhao
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Pôle de Recherches Sino-Français en Science du Vivant et Génomique, Laboratory of Molecular Pathology, Shanghai Rui Jin Hospital, Shanghai, China
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12
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Cornell RB, Ridgway ND. CTP:phosphocholine cytidylyltransferase: Function, regulation, and structure of an amphitropic enzyme required for membrane biogenesis. Prog Lipid Res 2015; 59:147-71. [PMID: 26165797 DOI: 10.1016/j.plipres.2015.07.001] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 07/07/2015] [Accepted: 07/07/2015] [Indexed: 12/12/2022]
Abstract
CTP:phosphocholine cytidylyltransferase (CCT) catalyzes a rate-limiting and regulated step in the CDP-choline pathway for the synthesis of phosphatidylcholine (PC) and PC-derived lipids. Control of CCT activity is multi-layered, and includes direct regulation by reversible membrane binding involving a built-in lipid compositional sensor. Thus CCT contributes to phospholipid compositional homeostasis. CCT also modifies the curvature of its target membrane. Knowledge of CCT structure and regulation of its catalytic function are relatively advanced compared to many lipid metabolic enzymes, and are reviewed in detail. Recently the genetic origins of two human developmental and lipogenesis disorders have been traced to mutations in the gene for CCTα.
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Affiliation(s)
- Rosemary B Cornell
- Department of Molecular Biology and Biochemistry and the Department of Chemistry, Simon Fraser University, Burnaby, B.C. V5A-1S6, Canada.
| | - Neale D Ridgway
- Departments of Pediatrics, and Biochemistry and Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia B3H-4H7, Canada
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13
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Aitchison AJ, Arsenault DJ, Ridgway ND. Nuclear-localized CTP:phosphocholine cytidylyltransferase α regulates phosphatidylcholine synthesis required for lipid droplet biogenesis. Mol Biol Cell 2015; 26:2927-38. [PMID: 26108622 PMCID: PMC4571330 DOI: 10.1091/mbc.e15-03-0159] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 06/16/2015] [Indexed: 12/31/2022] Open
Abstract
Phosphatidylcholine (PC) synthesis by the CDP-choline pathway in mammalian cells regulates lipid droplet size and triacylglycerol storage. Mechanistically this involves increased CCTα expression and translocation to the nuclear envelope. CCTα regulates the PC synthesis required for lipid droplet biogenesis without associating with the surface of the particle. The reversible association of CTP:phosphocholine cytidylyltransferase α (CCTα) with membranes regulates the synthesis of phosphatidylcholine (PC) by the CDP-choline (Kennedy) pathway. Based on results with insect CCT homologues, translocation of nuclear CCTα onto cytoplasmic lipid droplets (LDs) is proposed to stimulate the synthesis of PC that is required for LD biogenesis and triacylglycerol (TAG) storage. We examined whether this regulatory mechanism applied to LD biogenesis in mammalian cells. During 3T3-L1 and human preadipocyte differentiation, CCTα expression and PC synthesis was induced. In 3T3-L1 cells, CCTα translocated from the nucleoplasm to the nuclear envelope and cytosol but did not associate with LDs. The enzyme also remained in the nucleus during human adipocyte differentiation. RNAi silencing in 3T3-L1 cells showed that CCTα regulated LD size but did not affect TAG storage or adipogenesis. LD biogenesis in nonadipocyte cell lines treated with oleate also promoted CCTα translocation to the nuclear envelope and/or cytoplasm but not LDs. In rat intestinal epithelial cells, CCTα silencing increased LD size, but LD number and TAG deposition were decreased due to oleate-induced cytotoxicity. We conclude that CCTα increases PC synthesis for LD biogenesis by translocation to the nuclear envelope and not cytoplasmic LDs.
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Affiliation(s)
- Adam J Aitchison
- Departments of Pediatrics and of Biochemistry and Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Daniel J Arsenault
- Departments of Pediatrics and of Biochemistry and Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Neale D Ridgway
- Departments of Pediatrics and of Biochemistry and Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, NS B3H 4R2, Canada
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14
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Abstract
Tricyclodecan-9-yl-xanthogenate (D609) is an antioxidative molecule with antiproliferative and neuroprotective properties in a variety of cells. Previously, we have shown that D609 decreased the proliferation of neural progenitor cells. In this study, we examined the antioxidative property of D609 on neural progenitor cells isolated from the subventricular zone of the rat brain. Cellular oxidation was assessed by measuring the ATP content of the cells. Our results show that D609 decreased the ATP content of the neural progenitor cells by ∼40%, suggesting the possible inhibition of cellular metabolic activity. Cytochrome c oxidase (Cox), also known as complex IV of the electron transport chain, is a terminal enzyme involved in the oxidation of substrates resulting in the generation of energy required for the cellular activity. Therefore, regulating the activity of Cox could interfere with the generation of ATP, consequently affecting the proliferation of cells. Consistent with this hypothesis, we also observed a decrease in the Cox activity following the incubation of neural progenitor cells with D609. These results suggest that D609 could inhibit the activity of Cox and subsequent ATP synthesis in the neural progenitor cells.
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15
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Vaezi AE, Bepler G, Bhagwat NR, Malysa A, Rubatt JM, Chen W, Hood BL, Conrads TP, Wang L, Kemp CE, Niedernhofer LJ. Choline phosphate cytidylyltransferase-α is a novel antigen detected by the anti-ERCC1 antibody 8F1 with biomarker value in patients with lung and head and neck squamous cell carcinomas. Cancer 2014; 120:1898-907. [PMID: 24692084 DOI: 10.1002/cncr.28643] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 12/23/2013] [Accepted: 12/30/2013] [Indexed: 01/05/2023]
Abstract
BACKGROUND The determination of in situ protein levels of ERCC1 with the 8F1 monoclonal antibody is prognostic of survival in patients with non-small cell lung cancer (NSCLC). The authors previously demonstrated that 8F1 recognizes a second nuclear antigen. This antigen was identified and its value as a biomarker of clinical outcomes analyzed. METHODS The second antigen was identified by mass spectrometry. Protein identity and antibody specificity were confirmed through knockdown and overexpression experiments. Immunohistochemistry of 187 early-stage NSCLC samples and 60 head and neck squamous cell carcinomas (HNSCCs) was used to examine the influence of the second antigen on 8F1 immunoreactivity and its association with patient outcomes. RESULTS Choline phosphate cytidylyltransferase-α (CCTα, also known as phosphate cytidylyltransferase 1 choline alpha [PCYT1A], a phospholipid synthesis enzyme regulated by RAS) is the second antigen recognized by 8F1. In NSCLC samples, CCTα contributed (rho, 0.38) to 8F1 immunoreactivity. In samples of squamous cell carcinomas of the lung, CCTα was found to be the dominant determinant of 8F1 immunoreactivity, whereas its contribution in other subtypes of lung cancer was negligible. High expression of CCTα, but not ERCC1, was found to be prognostic of longer disease-free survival (log-rank P = .002) and overall survival (log-rank P = .056). Similarly, in patients with HNSCC, CCTα contributed strongly to 8F1 immunoreactivity (rho, 0.74), and high CCTα expression was found to be prognostic of survival (log-rank P = .022 for disease-free survival and P = .027 for overall survival). CONCLUSIONS CCTα is the second antigen detected by 8F1. High CCTα expression appears to be prognostic of survival in patients with NSCLC who are treated by surgery alone and patients with HNSCC. CCTα is a promising biomarker of patient survival and deserves further study.
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Affiliation(s)
- Alec E Vaezi
- Department of Otolaryngology and Head and Neck Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania; Cancer Institute, University of Pittsburgh, Pittsburgh, Pennsylvania
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16
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Lee J, Taneva SG, Holland BW, Tieleman DP, Cornell RB. Structural basis for autoinhibition of CTP:phosphocholine cytidylyltransferase (CCT), the regulatory enzyme in phosphatidylcholine synthesis, by its membrane-binding amphipathic helix. J Biol Chem 2013; 289:1742-55. [PMID: 24275660 DOI: 10.1074/jbc.m113.526970] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CTP:phosphocholine cytidylyltransferase (CCT) interconverts between an inactive soluble and active membrane-bound form in response to changes in membrane lipid composition. Activation involves disruption of an inhibitory interaction between the αE helices at the base of the active site and an autoinhibitory (AI) segment in the regulatory M domain and membrane insertion of the M domain as an amphipathic helix. We show that in the CCT soluble form the AI segment functions to suppress kcat and elevate the Km for CTP. The crystal structure of a CCT dimer composed of the catalytic and AI segments reveals an AI-αE interaction as a cluster of four amphipathic helices (two αE and two AI helices) at the base of the active sites. This interaction corroborates mutagenesis implicating multiple hydrophobic residues within the AI segment that contribute to its silencing function. The AI-αE interaction directs the turn at the C-terminal end of the AI helix into backbone-to-backbone contact with a loop (L2) at the opening to the active site, which houses the key catalytic residue, lysine 122. Molecular dynamics simulations suggest that lysine 122 side-chain orientations are constrained by contacts with the AI helix-turn, which could obstruct its engagement with substrates. This work deciphers how the CCT regulatory amphipathic helix functions as a silencing device.
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Affiliation(s)
- Jaeyong Lee
- From the Departments of Molecular Biology and Biochemistry and
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17
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Morton CC, Aitchison AJ, Gehrig K, Ridgway ND. A mechanism for suppression of the CDP-choline pathway during apoptosis. J Lipid Res 2013; 54:3373-84. [PMID: 24136823 DOI: 10.1194/jlr.m041434] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Inhibition of the CDP-choline pathway during apoptosis restricts the availability of phosphatidylcholine (PtdCho) for assembly of membranes and synthesis of signaling factors. The N-terminal nuclear localization signal (NLS) in CTP:phosphocholine cytidylyltransferase (CCT)α is removed during apoptosis but the caspase(s) involved and the contribution to suppression of the CDP-choline pathway is unresolved. In this study we utilized siRNA silencing of caspases in HEK293 cells and caspase 3-deficient MCF7 cells to show that caspase 3 is required for CCTα proteolysis and release from the nucleus during apoptosis. CCTα-Δ28 (a caspase-cleaved mimic) expressed in CCTα-deficient Chinese hamster ovary cells was cytosolic and had increased in vitro activity. However, [³H]choline labeling experiments in camptothecin-treated MCF7 cells and MCF7 cells expressing caspase 3 (MCF7-C3) revealed a global suppression of the CDP-choline pathway that was consistent with inhibition of a step prior to CCTα. In camptothecin-treated MCF7 and MCF7-C3 cells, choline kinase activity was unaffected; however, choline transport into cells was reduced by 30 and 60%, respectively. We conclude that caspase 3-mediated removal of the CCTα NLS contributes minimally to the inhibition of PtdCho synthesis during DNA damage-induced apoptosis. Rather, the CDP-choline pathway is inhibited by caspase 3-independent and -dependent suppression of choline transport into cells.
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Affiliation(s)
- Craig C Morton
- Departments of Pediatrics and Biochemistry and Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4R2
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