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Wong CC, Xu J, Bian X, Wu JL, Kang W, Qian Y, Li W, Chen H, Gou H, Liu D, Yat Luk ST, Zhou Q, Ji F, Chan LS, Shirasawa S, Sung JJ, Yu J. In Colorectal Cancer Cells With Mutant KRAS, SLC25A22-Mediated Glutaminolysis Reduces DNA Demethylation to Increase WNT Signaling, Stemness, and Drug Resistance. Gastroenterology 2020; 159:2163-2180.e6. [PMID: 32814111 DOI: 10.1053/j.gastro.2020.08.016] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [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: 02/25/2020] [Revised: 07/03/2020] [Accepted: 08/11/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Mutant KRAS promotes glutaminolysis, a process that uses steps from the tricarboxylic cycle to convert glutamine to α-ketoglutarate and other molecules via glutaminase and SLC25A22. This results in inhibition of demethylases and epigenetic alterations in cells that increase proliferation and stem cell features. We investigated whether mutant KRAS-mediated glutaminolysis affects the epigenomes and activities of colorectal cancer (CRC) cells. METHODS We created ApcminKrasG12D mice with intestine-specific knockout of SLC25A22 (ApcminKrasG12DSLC25A22fl/fl mice). Intestine tissues were collected and analyzed by histology, immunohistochemistry, and DNA methylation assays; organoids were derived and studied for stem cell features, along with organoids derived from 2 human colorectal tumor specimens. Colon epithelial cells (1CT) and CRC cells (DLD1, DKS8, HKE3, and HCT116) that expressed mutant KRAS, with or without knockdown of SLC25A22 or other proteins, were deprived of glutamine or glucose and assayed for proliferation, colony formation, glucose or glutamine consumption, and apoptosis; gene expression patterns were analyzed by RNA sequencing, proteins by immunoblots, and metabolites by liquid chromatography-mass spectrometry, with [U-13C5]-glutamine as a tracer. Cells and organoids with knocked down, knocked out, or overexpressed proteins were analyzed for DNA methylation at CpG sites using arrays. We performed immunohistochemical analyses of colorectal tumor samples from 130 patients in Hong Kong (57 with KRAS mutations) and Kaplan-Meier analyses of survival. We analyzed gene expression levels of colorectal tumor samples in The Cancer Genome Atlas. RESULTS CRC cells that express activated KRAS required glutamine for survival, and rapidly incorporated it into the tricarboxylic cycle (glutaminolysis); this process required SLC25A22. Cells incubated with succinate and non-essential amino acids could proliferate under glutamine-free conditions. Mutant KRAS cells maintained a low ratio of α-ketoglutarate to succinate, resulting in reduced 5-hydroxymethylcytosine-a marker of DNA demethylation, and hypermethylation at CpG sites. Many of the hypermethylated genes were in the WNT signaling pathway and at the protocadherin gene cluster on chromosome 5q31. CRC cells without mutant KRAS, or with mutant KRAS and knockout of SLC25A22, expressed protocadherin genes (PCDHAC2, PCDHB7, PCDHB15, PCDHGA1, and PCDHGA6)-DNA was not methylated at these loci. Expression of the protocadherin genes reduced WNT signaling to β-catenin and expression of the stem cell marker LGR5. ApcminKrasG12DSLC25A22fl/fl mice developed fewer colon tumors than ApcminKrasG12D mice (P < .01). Organoids from ApcminKrasG12DSLC25A22fl/fl mice had reduced expression of LGR5 and other markers of stemness compared with organoids derived from ApcminKrasG12D mice. Knockdown of SLC25A22 in human colorectal tumor organoids reduced clonogenicity. Knockdown of lysine demethylases, or succinate supplementation, restored expression of LGR5 to SLC25A22-knockout CRC cells. Knockout of SLC25A22 in CRC cells that express mutant KRAS increased their sensitivity to 5-fluorouacil. Level of SLC25A22 correlated with levels of LGR5, nuclear β-catenin, and a stem cell-associated gene expression pattern in human colorectal tumors with mutations in KRAS and reduced survival times of patients. CONCLUSIONS In CRC cells that express activated KRAS, SLC25A22 promotes accumulation of succinate, resulting in increased DNA methylation, activation of WNT signaling to β-catenin, increased expression of LGR5, proliferation, stem cell features, and resistance to 5-fluorouacil. Strategies to disrupt this pathway might be developed for treatment of CRC.
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Affiliation(s)
- Chi Chun Wong
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shenzhen Research Institute, Chinese University of Hong Kong, Hong Kong, China.
| | - Jiaying Xu
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shenzhen Research Institute, Chinese University of Hong Kong, Hong Kong, China
| | - Xiqing Bian
- State Key Laboratory for Quality Research in Chinese Medicines, Macau University of Science and Technology, Macao, China
| | - Jian-Lin Wu
- State Key Laboratory for Quality Research in Chinese Medicines, Macau University of Science and Technology, Macao, China
| | - Wei Kang
- Department of Anatomical and Chemical Pathology, Chinese University of Hong Kong, Hong Kong, China
| | - Yun Qian
- Department of Gastroenterology and Hepatology, Shenzhen University General Hospital, Shenzhen, China
| | - Weilin Li
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shenzhen Research Institute, Chinese University of Hong Kong, Hong Kong, China; Department of Surgery, Chinese University of Hong Kong, Hong Kong, China
| | - Huarong Chen
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shenzhen Research Institute, Chinese University of Hong Kong, Hong Kong, China
| | - Hongyan Gou
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shenzhen Research Institute, Chinese University of Hong Kong, Hong Kong, China
| | - Dabin Liu
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shenzhen Research Institute, Chinese University of Hong Kong, Hong Kong, China
| | - Simson Tsz Yat Luk
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shenzhen Research Institute, Chinese University of Hong Kong, Hong Kong, China
| | - Qiming Zhou
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shenzhen Research Institute, Chinese University of Hong Kong, Hong Kong, China
| | - Fenfen Ji
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shenzhen Research Institute, Chinese University of Hong Kong, Hong Kong, China
| | - Lam-Shing Chan
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shenzhen Research Institute, Chinese University of Hong Kong, Hong Kong, China
| | - Senji Shirasawa
- Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Joseph Jy Sung
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shenzhen Research Institute, Chinese University of Hong Kong, Hong Kong, China
| | - Jun Yu
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shenzhen Research Institute, Chinese University of Hong Kong, Hong Kong, China.
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Bastakoty D, Saraswati S, Joshi P, Atkinson J, Feoktistov I, Liu J, Harris JL, Young PP. Temporary, Systemic Inhibition of the WNT/β-Catenin Pathway promotes Regenerative Cardiac Repair following Myocardial Infarct. ACTA ACUST UNITED AC 2016; 2. [PMID: 28042617 DOI: 10.16966/2472-6990.111] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
AIMS The WNT/β-catenin pathway is temporarily activated in the heart following myocardial infarction (MI). Despite data from genetic models indicating both positive and negative roles for the WNT pathway depending on the model used, the effect of therapeutic inhibition of WNT pathway on post-injury outcome and the cellular mediators involved are not completely understood. Using a newly available, small molecule, GNF-6231, which averts WNT pathway activation by blocking secretion of all WNT ligands, we sought to investigate whether therapeutic inhibition of the WNT pathway temporarily after infarct can mitigate post injury cardiac dysfunction and fibrosis and the cellular mechanisms responsible for the effects. METHODS AND RESULTS Pharmacologic inhibition of the WNT pathway by post-MI intravenous injection of GNF-6231 in C57Bl/6 mice significantly reduced the decline in cardiac function (Fractional Shortening at day 30: 38.71 ± 4.13% in GNF-6231 treated vs. 34.89 ± 4.86% in vehicle-treated), prevented adverse cardiac remodeling, and reduced infarct size (9.07 ± 3.98% vs. 17.18 ± 4.97%). WNT inhibition augmented proliferation of interstitial cells, particularly in the distal myocardium, inhibited apoptosis of cardiomyocytes, and reduced myofibroblast proliferation in the peri-infarct region. In vitro studies showed that WNT inhibition increased proliferation of Sca1+ cardiac progenitors, improved survival of cardiomyocytes, and inhibited collagen I synthesis by cardiac myofibroblasts. CONCLUSION Systemic, temporary pharmacologic inhibition of the WNT pathway using an orally bioavailable drug immediately following MI resulted in improved function, reduced adverse remodeling and reduced infarct size in mice. Therapeutic WNT inhibition affected multiple aspects of infarct repair: it promoted proliferation of cardiac progenitors and other interstitial cells, inhibited myofibroblast proliferation, improved cardiomyocyte survival, and reduced collagen I gene expression by myofibroblasts. Our data point to a promising role for WNT inhibitory therapeutics as a new class of drugs to drive post-MI repair and prevent heart failure.
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Affiliation(s)
- Dikshya Bastakoty
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Sarika Saraswati
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Piyush Joshi
- Interdisciplinary Graduate Program, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - James Atkinson
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Department of Veterans Affairs Medical Center, Nashville, Tennessee, USA
| | - Igor Feoktistov
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jun Liu
- Genomics Institute of Novartis Research Foundation, San Diego, California, USA
| | - Jennifer L Harris
- Genomics Institute of Novartis Research Foundation, San Diego, California, USA
| | - Pampee P Young
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Department of Veterans Affairs Medical Center, Nashville, Tennessee, USA; Department of Internal Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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