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Yang L, Xiao Y, Deng S, Yan D, Li Z, Wang Y, Lei C. Signal Transducer and Activator of Transcription 4-Induced Up-Regulated LINC01278 Enhances Proliferation and Invasion of Non-Small Cell Lung Cancer Cells via the MicroRNA-877-5p/Activating Transcription Factor 4 Axis. Tissue Eng Regen Med 2024; 21:595-608. [PMID: 38466361 PMCID: PMC11087432 DOI: 10.1007/s13770-024-00625-5] [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: 05/30/2023] [Revised: 12/28/2023] [Accepted: 01/02/2024] [Indexed: 03/13/2024] Open
Abstract
BACKGROUND The purpose of this study was to investigate the specific effects of signal transducer and activator of transcription 4 (STAT4)-induced long intergenic nonprotein coding RNA 1278 (LINC01278) on the growth of non-small cell lung cancer (NSCLC) cells involved in the microRNA (miR)-877-5p/activated transcription factor 4 (ATF4) axis. METHODS NSCLC tumor tissue and adjacent normal tissue were collected. Human normal lung epithelial cell BEAS-2B and human NSCLC cell lines (H1299, H1975, A549, H2228) were collected. The expression levels of STAT4, LINC01278, miR-877-5p, and ATF4 were detected. A549 cells were screened for subsequent experiments. The proliferation ability of cells was detected by colony formation experiment. Cell apoptosis was tested by flow cytometry. Scratch test and transwell assay were used to detect the migration and invasion ability of cells. Biological function of LINC01278 in NSCLC was confirmed by xenograft experiments. RESULTS Low expression miR-877-5p and high expression of STAT4, LINC01278 and ATF4 were detected in NSCLC. Silenced LINC01278 in A549 cell depressed cell proliferation, migration and invasion, but facilitated cell apoptosis. LINC01278 was positively correlated with STAT4 and could directly bind to miR-877-5p. Upregulating miR-877-5p suppressed NSCLC cell progression, while downregulating miR-877-5p had the opposite effect. Upregulating miR-877-5p abrogated the effects of silenced LINC01278 on NSCLC cell progression. MiR-877-5p targeted ATF4. ATF4 upregulation could partly restore the carcinogenic effect of LINC01278 in vitro and in vivo. CONCLUSION Our data supports that STAT4-induced upregulation of LINC01278 promotes NSCLC progression by modulating the miR-877-5p/ATF4 axis, suggesting a novel direction for NSCLC treatment.
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Affiliation(s)
- LinZhu Yang
- Department of Thoracic Surgery, The First Affiliated Hospital of Kunming Medical University, No. 295, Xichang Road, KunMing City, 650032, YunNan Province, China
| | - Yi Xiao
- First Department of Pumonary and Critical Care Medicline, Yan'an Affiliated Hospital of Kunming Medical University, KunMing City, 650051, YunNan Province, China
| | - ShouJun Deng
- Department of Thoracic Surgery, Yan'an Affiliated Hospital of Kunming Medical University, 245 East Renmin Road, Panlong District, KunMing City, 650051, YunNan Province, China
| | - DaiLing Yan
- First Department of Pumonary and Critical Care Medicline, Yan'an Affiliated Hospital of Kunming Medical University, KunMing City, 650051, YunNan Province, China
| | - ZhenHua Li
- Department of Thoracic Surgery, Yan'an Affiliated Hospital of Kunming Medical University, 245 East Renmin Road, Panlong District, KunMing City, 650051, YunNan Province, China
| | - Ying Wang
- Department of Thoracic Surgery, Yan'an Affiliated Hospital of Kunming Medical University, 245 East Renmin Road, Panlong District, KunMing City, 650051, YunNan Province, China.
| | - ChangCheng Lei
- Department of Thoracic Surgery, The First Affiliated Hospital of Kunming Medical University, No. 295, Xichang Road, KunMing City, 650032, YunNan Province, China.
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Ma Y, Okuda S, Okanishi H, Xu M, Jin C, Endou H, Ohgaki R, Kanai Y. Upregulation of ATF4 mediates the cellular adaptation to pharmacologic inhibition of amino acid transporter LAT1 in pancreatic ductal adenocarcinoma cells. J Pharmacol Sci 2024; 155:14-20. [PMID: 38553134 DOI: 10.1016/j.jphs.2024.03.001] [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: 12/19/2023] [Revised: 02/05/2024] [Accepted: 03/04/2024] [Indexed: 04/02/2024] Open
Abstract
L-type amino acid transporter 1 (LAT1) is recognized as a promising target for cancer therapy; however, the cellular adaptive response to its pharmacological inhibition remains largely unexplored. This study examined the adaptive response to LAT1 inhibition using nanvuranlat, a high-affinity LAT1 inhibitor. Proteomic analysis revealed the activation of a stress-induced transcription factor ATF4 following LAT1 inhibition, aligning with the known cellular responses to amino acid deprivation. This activation was linked to the GCN2-eIF2α pathway which regulates translation initiation. Our results show that ATF4 upregulation counteracts the suppressive effect of nanvuranlat on cell proliferation in pancreatic ductal adenocarcinoma cell lines, suggesting a role for ATF4 in cellular adaptation to LAT1 inhibition. Importantly, dual targeting of LAT1 and ATF4 exhibited more substantial anti-proliferative effects in vitro than individual treatments. This study underscores the potential of combining LAT1 and ATF4 inhibition as a therapeutic strategy in cancer treatment.
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Affiliation(s)
- Yu Ma
- Department of Bio-system Pharmacology, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Suguru Okuda
- Department of Bio-system Pharmacology, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hiroki Okanishi
- Department of Bio-system Pharmacology, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Minhui Xu
- Department of Bio-system Pharmacology, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Chunhuan Jin
- Department of Bio-system Pharmacology, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hitoshi Endou
- J-Pharma Co., Ltd., Yokohama, Kanagawa, 230-0046, Japan
| | - Ryuichi Ohgaki
- Department of Bio-system Pharmacology, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan; Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yoshikatsu Kanai
- Department of Bio-system Pharmacology, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan; Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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Pelligra A, Mrugala J, Griess K, Kirschner P, Nortmann O, Bartosinska B, Köster A, Krupenko NI, Gebel D, Westhoff P, Steckel B, Eberhard D, Herebian D, Belgardt BF, Schrader J, Weber APM, Krupenko SA, Lammert E. Pancreatic islet protection at the expense of secretory function involves serine-linked mitochondrial one-carbon metabolism. Cell Rep 2023; 42:112615. [PMID: 37294632 PMCID: PMC10592470 DOI: 10.1016/j.celrep.2023.112615] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 03/30/2023] [Accepted: 05/23/2023] [Indexed: 06/11/2023] Open
Abstract
Type 2 diabetes is characterized by insulin hypersecretion followed by reduced glucose-stimulated insulin secretion (GSIS). Here we show that acute stimulation of pancreatic islets with the insulin secretagogue dextrorphan (DXO) or glibenclamide enhances GSIS, whereas chronic treatment with high concentrations of these drugs reduce GSIS but protect islets from cell death. Bulk RNA sequencing of islets shows increased expression of genes for serine-linked mitochondrial one-carbon metabolism (OCM) after chronic, but not acute, stimulation. In chronically stimulated islets, more glucose is metabolized to serine than to citrate, and the mitochondrial ATP/ADP ratio decreases, whereas the NADPH/NADP+ ratio increases. Activating transcription factor-4 (Atf4) is required and sufficient to activate serine-linked mitochondrial OCM genes in islets, with gain- and loss-of-function experiments showing that Atf4 reduces GSIS and is required, but not sufficient, for full DXO-mediated islet protection. In sum, we identify a reversible metabolic pathway that provides islet protection at the expense of secretory function.
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Affiliation(s)
- Angela Pelligra
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Jessica Mrugala
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany; Institute for Vascular and Islet Cell Biology, German Diabetes Center (DDZ), Leibniz Center for Diabetes Research at Heinrich Heine University, 40225 Düsseldorf, Germany; German Center for Diabetes Research (DZD e.V.), Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Kerstin Griess
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Philip Kirschner
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Oliver Nortmann
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Barbara Bartosinska
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Andrea Köster
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Natalia I Krupenko
- University of North Carolina (UNC) Nutrition Research Institute, UNC Chapel Hill, Chapel Hill, NC, USA
| | - Dominik Gebel
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Philipp Westhoff
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science (CEPLAS), Heinrich Heine University, 40225 Düsseldorf, Germany; Cluster of Excellence on Plant Science (CEPLAS), Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Bodo Steckel
- Department of Molecular Cardiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Daniel Eberhard
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany; Institute for Vascular and Islet Cell Biology, German Diabetes Center (DDZ), Leibniz Center for Diabetes Research at Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Diran Herebian
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Bengt-Frederik Belgardt
- Institute for Vascular and Islet Cell Biology, German Diabetes Center (DDZ), Leibniz Center for Diabetes Research at Heinrich Heine University, 40225 Düsseldorf, Germany; German Center for Diabetes Research (DZD e.V.), Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Jürgen Schrader
- Department of Molecular Cardiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Andreas P M Weber
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science (CEPLAS), Heinrich Heine University, 40225 Düsseldorf, Germany; Cluster of Excellence on Plant Science (CEPLAS), Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Sergey A Krupenko
- University of North Carolina (UNC) Nutrition Research Institute, UNC Chapel Hill, Chapel Hill, NC, USA
| | - Eckhard Lammert
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany; Institute for Vascular and Islet Cell Biology, German Diabetes Center (DDZ), Leibniz Center for Diabetes Research at Heinrich Heine University, 40225 Düsseldorf, Germany; German Center for Diabetes Research (DZD e.V.), Helmholtz Zentrum München, 85764 Neuherberg, Germany.
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ATF4 Transcriptionally Activates SHH to Promote Proliferation, Invasion, and Migration of Gastric Cancer Cells. Cancers (Basel) 2023; 15:cancers15051429. [PMID: 36900220 PMCID: PMC10000907 DOI: 10.3390/cancers15051429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 02/18/2023] [Accepted: 02/20/2023] [Indexed: 03/06/2023] Open
Abstract
Activating transcription factor 4 (ATF4) is a DNA-binding protein widely generated in mammals, which has two biological characteristics that bind the cAMP response element (CRE). The mechanism of ATF4 as a transcription factor in gastric cancer affecting the Hedgehog pathway remains unclear. Here, we observed that ATF4 was markedly upregulated in gastric cancer (GC) using immunohistochemistry and Western blotting assays in 80 paraffin-embedded GC samples and 4 fresh samples and para-cancerous tissues. ATF4 knockdown using lentiviral vectors strongly inhibited the proliferation and invasion of GC cells. ATF4 upregulation using lentiviral vectors promoted the proliferation and invasion of GC cells. We predicted that the transcription factor ATF4 is bound to the SHH promoter via the JASPA database. Transcription factor ATF4 is bound to the promoter region of SHH to activate the Sonic Hedgehog pathway. Mechanistically, rescue assays showed that ATF4 regulated gastric cancer cells' proliferation and invasive ability through SHH. Similarly, ATF4 enhanced the tumor formation of GC cells in a xenograft model.
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Identification and Validation of Ferroptosis-Related Genes in Sevoflurane-Induced Hippocampal Neurotoxicity. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:4435161. [PMID: 36238640 PMCID: PMC9553355 DOI: 10.1155/2022/4435161] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 08/25/2022] [Indexed: 11/17/2022]
Abstract
Background Sevoflurane is one of the most popular inhalational anesthetics during perioperative period but presenting neurotoxicity among pediatric and aged populations. Recent experiments in vivo and in vitro have indicated that ferroptosis may contribute to the neurotoxicity of sevoflurane anesthesia. However, the exact mechanism is still unclear. Methods In current study, we explored the differential expressed genes (DEGs) in HT-22 mouse hippocampal neuronal cells after sevoflurane anesthesia using RNA-seq. Differential expressed ferroptosis-related genes (DEFRGs) were screened and analyzed by Gene Ontology (GO) and pathway enrichment analysis. Protein-to-protein interaction (PPI) network was constructed by the Search Tool for the Retrieval of Interacting Genes (STRING). Significant modules and the hub genes were identified by using Cytoscape. The Connectivity Map (cMAP) was used for screening drug candidates targeting the identified DEFRGs. Potential TF-gene network and drug-gene pairs were established towards the hub genes. In final, we validated these results in experiments. Results A total of 37 ferroptosis-related genes (18 upregulated and 19 downregulated) after sevoflurane exposure in hippocampal neuronal cells were finally identified. These differentially expressed genes were mainly involved into the biological processes of cellular response to oxidative stress. Pathway analysis indicated that these genes were involved in ferroptosis, mTOR signaling pathway, and longevity-regulating pathway. PPI network was constructed. 10 hub genes including Prkaa2, Chac1, Arntl, Tfrc, Slc7a11, Atf4, Mgst1, Lpin1, Atf3, and Sesn2 were found. Top 10 drug candidates, gene-drug networks, and TFs targeting these genes were finally identified. These results were validated in experiments. Conclusion Our results suggested that ferroptosis-related genes play roles in sevoflurane anesthesia-related hippocampal neuron injury and offered the hub genes and potential therapeutic agents for investigating and treatment of this neurotoxicity after sevoflurane exposure. Finally, therapeutic effect of these drug candidates and function of potential ferroptosis targets should be further investigated for treatment and clarifying mechanisms of sevoflurane anesthesia-induced neuron injury in future research.
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Downregulation of HULC Induces Ferroptosis in Hepatocellular Carcinoma via Targeting of the miR-3200-5p/ATF4 Axis. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:9613095. [PMID: 35615577 PMCID: PMC9126659 DOI: 10.1155/2022/9613095] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 04/12/2022] [Accepted: 04/30/2022] [Indexed: 12/20/2022]
Abstract
Hepatocellular carcinoma is a malignant tumor that poses a serious threat to human health. Ferroptosis, which represents an identified type of regulated iron-dependent cell death, may play an important role in hepatocellular carcinoma. However, it is unclear as to whether ferroptosis is involved with the mechanisms of lncRNA HULC in liver cancer cells. Here, we show that knockdown of HULC increases ferroptosis and oxidative stress in liver cancer cells. We also found changes in some related miRNAs in cells treated with HULC siRNA. Differential miRNA expression levels were determined with the use of high-throughput sequencing and prediction target genes identified using bioinformatics analysis. HULC was found to function as a ceRNA of miR-3200-5p, and miR-3200-5p regulates ferroptosis by targeting ATF4, resulting in the inhibition of proliferation and metastasis within HCC cells. In summary, these findings illuminate some of the molecular mechanisms through which downregulation of HULC induces liver cancer cell ferroptosis by targeting the miR-3200-5p/ATF4 axis to modulate the development of hepatocellular carcinoma.
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KLF16 enhances stress tolerance of colorectal carcinomas by modulating nucleolar homeostasis and translational reprogramming. Mol Ther 2022; 30:2828-2843. [PMID: 35524408 PMCID: PMC9372374 DOI: 10.1016/j.ymthe.2022.04.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 04/25/2022] [Accepted: 04/29/2022] [Indexed: 12/22/2022] Open
Abstract
Translational reprogramming is part of the unfolded protein response (UPR) during endoplasmic reticulum (ER) stress, which acts to the advantage of cancer growth and development in different stress conditions. But the mechanism of ER stress-related translational reprogramming in colorectal carcinoma (CRC) progression remains unclear. Here, we identified that Krüppel-Like Factor 16 (KLF16) can promote CRC progression and stress tolerance through translational reprogramming. The expression of KLF16 was upregulated in CRC tissues and associated with poor prognosis for CRC patients. We found that ER stress inducers can recruit KLF16 to the nucleolus and increase its interaction with two essential proteins for nucleolar homeostasis, nucleophosmin1 (NPM1) and fibrillarin (FBL). Moreover, knockdown of KLF16 can dysregulate nucleolar homeostasis in CRC cells. Translation-reporter system and polysome profiling assays further showed that KLF16 can effectively promote cap-independent translation of ATF4, which can enhance ER-phagy and proliferation of CRC cells. Overall, our study unveils a previously unrecognized role for KLF16 as an ER stress regulator through mediating translational reprogramming to enhance stress tolerance of CRC cells and provides a potential therapeutic vulnerability.
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Zhao L, Chen H, Zhang Q, Ma J, Hu H, Xu L. ATF4-mediated microRNA-145/HDAC4/p53 axis affects resistance of colorectal cancer cells to 5-fluorouracil by regulating autophagy. Cancer Chemother Pharmacol 2022; 89:595-607. [PMID: 35312836 DOI: 10.1007/s00280-021-04393-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 12/21/2021] [Indexed: 01/07/2023]
Abstract
BACKGROUND The impact of activating transcription factor 4 (ATF4), differentially expressed in colorectal cancer (CRC), on 5-Fluorouracil (5-FU) chemoresistance has not been fully explained. The purpose of this study is to evaluate the clinical significance of ATF4-mediated microRNA-145 (miR-145)/histone deacetylase 4 (HDAC4)/p53 axis in CRC. METHODS Initially, the expression of ATF4, miR-145, HDAC4, and p53 in CRC tissues and cells was quantified by RT-qPCR and immunoblotting. Next, luciferase activity and chromatin immunoprecipitation assays were performed to verify the binding affinity among miR-145, ATF4, and HDAC4. Moreover, proliferation, clone formation, and apoptosis in CRC cells treated with 5-FU were assessed after gain- or loss-of-function of ATF4, miR-145, and/or HDAC4. Furthermore, the tumorigenicity and chemoresistance of CRC cells in mice were assayed for validating the in vitro findings. RESULTS ATF4 and HDAC4 were highly expressed, while miR-145 and p53 were poorly expressed in CRC tissues and cells. miR-145 targeted and negatively regulated HDAC4 to activate p53, and miR-145 expression was suppressed by ATF4. Of note, ATF4 facilitated cell proliferation and clone formation ability and repressed apoptosis to promote autophagy and chemoresistance of CRC cells by regulating the miR-145/HDAC4/p53 axis. In vivo experiment elucidated that ATF4-mediated miR-145/HDAC4/p53 axis enhanced tumorigenesis and resistance of CRC cells to 5-FU. CONCLUSION In conclusion, ATF4-mediated miR-145 inhibition accelerated autophagy of CRC cells and boosted their resistance to 5-FU via the HDAC4/p53 axis.
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Affiliation(s)
- Lin Zhao
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Soochow University, No. 899, Pinghai Road, Suzhou, 215006, Jiangsu, China
- Department of General Surgery, Mudanjiang First People's Hospital, Mudanjiang, 157011, China
| | - Hong Chen
- Department of General Surgery, Suzhou Dushu Lake Hospital Affiliated to Soochow University, Suzhou, 215000, China
| | - QingYi Zhang
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Soochow University, No. 899, Pinghai Road, Suzhou, 215006, Jiangsu, China
| | - Jin Ma
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Soochow University, No. 899, Pinghai Road, Suzhou, 215006, Jiangsu, China
| | - Hao Hu
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Soochow University, No. 899, Pinghai Road, Suzhou, 215006, Jiangsu, China.
| | - Lu Xu
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Soochow University, No. 899, Pinghai Road, Suzhou, 215006, Jiangsu, China.
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Spliced or Unspliced, That Is the Question: The Biological Roles of XBP1 Isoforms in Pathophysiology. Int J Mol Sci 2022; 23:ijms23052746. [PMID: 35269888 PMCID: PMC8910952 DOI: 10.3390/ijms23052746] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 02/27/2022] [Accepted: 02/27/2022] [Indexed: 01/27/2023] Open
Abstract
X-box binding protein 1 (XBP1) is a member of the CREB/ATF basic region leucine zipper family transcribed as the unspliced isoform (XBP1-u), which, upon exposure to endoplasmic reticulum stress, is spliced into its spliced isoform (XBP1-s). XBP1-s interacts with the cAMP response element of major histocompatibility complex class II gene and plays critical role in unfolded protein response (UPR) by regulating the transcriptional activity of genes involved in UPR. XBP1-s is also involved in other physiological pathways, including lipid metabolism, insulin metabolism, and differentiation of immune cells. Its aberrant expression is closely related to inflammation, neurodegenerative disease, viral infection, and is crucial for promoting tumor progression and drug resistance. Meanwhile, recent studies reported that the function of XBP1-u has been underestimated, as it is not merely a precursor of XBP1-s. Instead, XBP-1u is a critical factor involved in various biological pathways including autophagy and tumorigenesis through post-translational regulation. Herein, we summarize recent research on the biological functions of both XBP1-u and XBP1-s, as well as their relation to diseases.
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