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Kuramoto K, Yamamoto M, Suzuki S, Togashi K, Sanomachi T, Kitanaka C, Okada M. Inhibition of the Lipid Droplet-Peroxisome Proliferator-Activated Receptor α Axis Suppresses Cancer Stem Cell Properties. Genes (Basel) 2021; 12:99. [PMID: 33466690 DOI: 10.3390/genes12010099] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 01/08/2021] [Accepted: 01/09/2021] [Indexed: 02/07/2023] Open
Abstract
Cancer stem cells (CSCs), having both self-renewal and tumorigenic capacity, utilize an energy metabolism system different from that of non-CSCs. Lipid droplets (LDs) are organelles that store neutral lipids, including triacylglycerol. Previous studies demonstrated that LDs are formed and store lipids as an energy source in some CSCs. LDs play central roles not only in lipid storage, but also as a source of endogenous lipid ligands, which are involved in numerous signaling pathways, including the peroxisome proliferator-activated receptor (PPAR) signaling pathway. However, it remains unclear whether LD-derived signal transduction is involved in the maintenance of the properties of CSCs. We investigated the roles of LDs in cancer stemness using pancreatic and colorectal CSCs and isogenic non-CSCs. PPARα was activated in CSCs in which LDs accumulated, but not in non-CSCs, and pharmacological and genetic inhibition of PPARα suppressed cancer stemness. In addition, inhibition of both re-esterification and lipolysis pathways suppressed cancer stemness. Our study suggested that LD metabolic turnover accompanying PPARα activation is a promising anti-CSC therapeutic target.
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Huh JY, Reilly SM, Abu-Odeh M, Murphy AN, Mahata SK, Zhang J, Cho Y, Seo JB, Hung CW, Green CR, Metallo CM, Saltiel AR. TANK-Binding Kinase 1 Regulates the Localization of Acyl-CoA Synthetase ACSL1 to Control Hepatic Fatty Acid Oxidation. Cell Metab 2020; 32:1012-1027.e7. [PMID: 33152322 PMCID: PMC7710607 DOI: 10.1016/j.cmet.2020.10.010] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/20/2020] [Accepted: 10/12/2020] [Indexed: 12/12/2022]
Abstract
Hepatic TANK (TRAF family member associated NFκB activator)-binding kinase 1 (TBK1) activity is increased during obesity, and administration of a TBK1 inhibitor reduces fatty liver. Surprisingly, liver-specific TBK1 knockout in mice produces fatty liver by reducing fatty acid oxidation. TBK1 functions as a scaffolding protein to localize acyl-CoA synthetase long-chain family member 1 (ACSL1) to mitochondria, which generates acyl-CoAs that are channeled for β-oxidation. TBK1 is induced during fasting and maintained in the unphosphorylated, inactive state, enabling its high affinity binding to ACSL1 in mitochondria. In TBK1-deficient liver, ACSL1 is shifted to the endoplasmic reticulum to promote fatty acid re-esterification in lieu of oxidation in response to fasting, which accelerates hepatic lipid accumulation. The impaired fatty acid oxidation in TBK1-deficient hepatocytes is rescued by the expression of kinase-dead TBK1. Thus, TBK1 operates as a rheostat to direct the fate of fatty acids in hepatocytes, supporting oxidation when inactive during fasting and promoting re-esterification when activated during obesity.
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Affiliation(s)
- Jin Young Huh
- Department of Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - Shannon M Reilly
- Department of Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - Mohammad Abu-Odeh
- Department of Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - Anne N Murphy
- Department of Pharmacology, University of California, San Diego, San Diego, CA 92093, USA
| | - Sushil K Mahata
- Department of Medicine, University of California, San Diego, San Diego, CA 92093, USA; VA San Diego Healthcare System, San Diego, CA 92161, USA
| | - Jinyu Zhang
- Division of Biological Sciences, University of California, San Diego, San Diego, CA 92093, USA
| | - Yoori Cho
- Division of Biological Sciences, University of California, San Diego, San Diego, CA 92093, USA
| | - Jong Bae Seo
- Department of Biosciences, Mokpo National University, Jeonnam 58554, Republic of Korea
| | - Chao-Wei Hung
- Department of Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - Courtney R Green
- Department of Bioengineering, University of California, San Diego, San Diego, CA 92093, USA
| | - Christian M Metallo
- Department of Bioengineering, University of California, San Diego, San Diego, CA 92093, USA
| | - Alan R Saltiel
- Department of Medicine, University of California, San Diego, San Diego, CA 92093, USA; Department of Pharmacology, University of California, San Diego, San Diego, CA 92093, USA.
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Brose SA, Golovko MY. A rapid oxygen exchange on prostaglandins in plasma represents plasma esterase activity that is inhibited by diethylumbelliferyl phosphate with high affinity. Rapid Commun Mass Spectrom 2012; 26:2472-6. [PMID: 22976214 PMCID: PMC3489958 DOI: 10.1002/rcm.6367] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
RATIONALE Fatty acids (FA) labeled with (18) O at the carboxyl group, including oxidized species (FA(18) O), are a useful, low-cost, and easy to prepare tool for quantitative and qualitative mass spectrometry (MS) analysis in biological systems. In addition, they are used to trace the fate of FAs in metabolic pathways including FA re-esterification and lipid remodeling pathways. Although a rapid (18) O exchange on FA(18) O in biological systems has been reported, the mechanism contributing to (18) O exchange has not been fully evaluated. This gap in knowledge limits the use of FA(18) O as a standard for MS and complicates data interpretation for FA metabolism in biological systems. METHODS In the present study we have addressed a number of possible mechanisms for a rapid (18) O exchange on prostaglandin E(2) (PGE(2) ) using rat plasma as a model. High-performance liquid chromatography coupled with electrospray ionization triple quadrupole MS in the multiple reaction monitoring mode was used for quantification. RESULTS The major mechanism for a rapid (18) O exchange on PGE(2) (18) O in rat plasma is PGE(2) processing with esterases, while FA re-esterification and non-enzymatic mechanisms do not significantly contribute to this phenomenon. In addition, we report a highly effective inhibition of (18) O exchange with diethylumbelliferyl phosphate that can be used to stabilize FA(18) O in biological samples. CONCLUSIONS These data indicate the necessity to consider esterase activity when FA(18) O are used to study FA metabolism, and the importance of esterase activity inhibition when FA(18) O are used as internal standards for MS analysis in biological systems. In addition, the results provide a rational for the development of new approaches to study esterase activities and affinity towards modified FA.
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Affiliation(s)
- Stephen A. Brose
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota, Grand Forks, ND 58202-9037
| | - Mikhail Y. Golovko
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota, Grand Forks, ND 58202-9037
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