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Chen F, Xiao M, Hu S, Wang M. Keap1-Nrf2 pathway: a key mechanism in the occurrence and development of cancer. Front Oncol 2024; 14:1381467. [PMID: 38634043 PMCID: PMC11021590 DOI: 10.3389/fonc.2024.1381467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Accepted: 03/19/2024] [Indexed: 04/19/2024] Open
Abstract
The Keap1-Nrf2 signaling pathway is a major regulator of the cytoprotective response, participating in endogenous and exogenous stress caused by ROS (reactive oxygen species). Nrf2 is the core of this pathway. We summarized the literature on Keap1-Nrf2 signaling pathway and summarized the following three aspects: structure, function pathway, and cancer and clinical application status. This signaling pathway is similar to a double-edged sword: on the one hand, Nrf2 activity can protect cells from oxidative and electrophilic stress; on the other hand, increasing Nrf2 activity can enhance the survival and proliferation of cancer cells. Notably, oxidative stress is also considered a marker of cancer in humans. Keap1-Nrf2 signaling pathway, as a typical antioxidant stress pathway, is abnormal in a variety of human malignant tumor diseases (such as lung cancer, liver cancer, and thyroid cancer). In recent years, research on the Keap1-Nrf2 signaling pathway has become increasingly in-depth and detailed. Therefore, it is of great significance for cancer prevention and treatment to explore the molecular mechanism of the occurrence and development of this pathway.
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Affiliation(s)
- Feilong Chen
- Sports Medicine Key Laboratory of Sichuan Province, Expert Centre of Sichuan Province, Institute of Sports Medicine and Health, Chengdu Sport University, Chengdu, China
| | - Mei Xiao
- College of Bioengineering, Chongqing University, Chongqing, China
| | - Shaofan Hu
- Department of Biochemistry and Molecular Biology, Third Military Medical University (Army Medical University), Chongqing, China
| | - Meng Wang
- Department of Biochemistry and Molecular Biology, Third Military Medical University (Army Medical University), Chongqing, China
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Liu K, Hu S, Qiu L, Wang M, Zhang Z, Sun G, Zhang Y. Nrf1 is not a direct target gene of SREBP1, albeit both are integrated into the rapamycin-responsive regulatory network in human hepatoma cells. PLoS One 2023; 18:e0294508. [PMID: 38011090 PMCID: PMC10681226 DOI: 10.1371/journal.pone.0294508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 11/02/2023] [Indexed: 11/29/2023] Open
Abstract
The essential role of protein degradation by ubiquitin-proteasome system is exerted primarily for maintaining cellular protein homeostasis. The transcriptional activation of proteasomal genes by mTORC1 signaling depends on Nrf1, but whether this process is directly via SREBP1 remains elusive. In this study, our experiment evidence revealed that Nrf1 is not a direct target of SREBP1, although both are involved in the rapamycin-responsive regulatory networks. Closely scrutinizing two distinct transcriptomic datasets unraveled no significant changes in transcriptional expression of Nrf1 and almost all proteasomal subunits in either siSREBP2-silencing cells or SREBP1-∕-MEFs, when compared to equivalent controls. However, distinct upstream signaling to Nrf1 dislocation by p97 and its processing by DDI1/2, along with downstream proteasomal expression, may be monitored by mTOR signaling, to various certain extents, depending on distinct experimental settings in different types of cells. Our further evidence has been obtained from DDI1-∕-(DDI2insC) cells, demonstrating that putative effects of mTOR on the rapamycin-responsive signaling to Nrf1 and proteasomes may also be executed partially through a DDI1/2-independent mechanism, albeit the detailed regulatory events remain to be determined.
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Affiliation(s)
- Keli Liu
- Bioengineering College, Chongqing University, Shapingba District, Chongqing, China
- Chongqing University Jiangjin Hospital, School of Medicine, Chongqing University, Jiangjin District, Chongqing, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Chongqing University, Shapingba District, Chongqing, China
| | - Shaofan Hu
- Bioengineering College, Chongqing University, Shapingba District, Chongqing, China
- Chongqing University Jiangjin Hospital, School of Medicine, Chongqing University, Jiangjin District, Chongqing, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Chongqing University, Shapingba District, Chongqing, China
| | - Lu Qiu
- Bioengineering College, Chongqing University, Shapingba District, Chongqing, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Chongqing University, Shapingba District, Chongqing, China
- School of Life Sciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Meng Wang
- Bioengineering College, Chongqing University, Shapingba District, Chongqing, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Chongqing University, Shapingba District, Chongqing, China
| | - Zhengwen Zhang
- Laboratory of Neuroscience, Institute of Cognitive Neuroscience and School of Pharmacy, University College London, London, England, United Kingdom
| | - Guiyin Sun
- Chongqing University Jiangjin Hospital, School of Medicine, Chongqing University, Jiangjin District, Chongqing, China
| | - Yiguo Zhang
- Chongqing University Jiangjin Hospital, School of Medicine, Chongqing University, Jiangjin District, Chongqing, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Chongqing University, Shapingba District, Chongqing, China
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Chen F, Xiao M, Feng J, Wufur R, Liu K, Hu S, Zhang Y. Different Inhibition of Nrf2 by Two Keap1 Isoforms α and β to Shape Malignant Behaviour of Human Hepatocellular Carcinoma. Int J Mol Sci 2022; 23:ijms231810342. [PMID: 36142252 PMCID: PMC9499251 DOI: 10.3390/ijms231810342] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/25/2022] [Accepted: 09/02/2022] [Indexed: 12/14/2022] Open
Abstract
Nrf2 (nuclear factor E2-related factor 2, encoded by Nfe2l2) acts as a master transcriptional regulator in mediating antioxidant, detoxification, and cytoprotective responses against oxidative, electrophilic, and metabolic stress, but also plays a crucial role in cancer metabolism and multiple oncogenic pathways, whereas the redox sensor Keap1 functions as a predominant inhibitor of Nrf2 and, hence, changes in its expression abundance directly affect the Nrf2 stability and transcriptional activity. However, nuanced functional isoforms of Keap1 α and β have rarely been identified to date. Herein, we have established four distinct cell models stably expressing Keap1-/-, Keap1β(Keap1Δ1-31), Keap1-Restored, and Keap1α-Restored aiming to gain a better understanding of similarities and differences of two Keap1 isoforms between their distinct regulatory profiles. Our experimental evidence revealed that although Keap1 and its isoforms are still localized in the cytoplasmic compartments, they elicited differential inhibitory effects on Nrf2 and its target HO-1. Furthermore, transcriptome sequencing unraveled that they possess similar but different functions. Such functions were further determined by multiple experiments in vivo (i.e., subcutaneous tumour formation in nude mice) and in vitro (e.g., cell cloning, infection, migration, wound healing, cell cycle, apoptosis, CAT enzymatic activity, and intracellular GSH levels). Of note, the results obtained from tumourigenesis experiments in xenograft model mice were verified based on the prominent changes in the PTEN signaling to the PI3K-AKT-mTOR pathways, in addition to substantially aberrant expression patterns of those typical genes involved in the EMT (epithelial-mesenchymal transition), cell cycle, and apoptosis.
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Affiliation(s)
- Feilong Chen
- College of Bioengineering, Graduate School, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
- Chongqing University Jiangjin Hospital, School of Medicine, Chongqing University, No. 725 Jiangzhou Avenue, Dingshan Street, Jiangjin District, Chongqing 402260, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Faculty of Medical Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
| | - Mei Xiao
- College of Bioengineering, Graduate School, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Faculty of Medical Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
| | - Jing Feng
- College of Bioengineering, Graduate School, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
- Chongqing University Jiangjin Hospital, School of Medicine, Chongqing University, No. 725 Jiangzhou Avenue, Dingshan Street, Jiangjin District, Chongqing 402260, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Faculty of Medical Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
| | - Reziyamu Wufur
- College of Bioengineering, Graduate School, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
- Chongqing University Jiangjin Hospital, School of Medicine, Chongqing University, No. 725 Jiangzhou Avenue, Dingshan Street, Jiangjin District, Chongqing 402260, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Faculty of Medical Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
| | - Keli Liu
- College of Bioengineering, Graduate School, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
- Chongqing University Jiangjin Hospital, School of Medicine, Chongqing University, No. 725 Jiangzhou Avenue, Dingshan Street, Jiangjin District, Chongqing 402260, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Faculty of Medical Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
| | - Shaofan Hu
- College of Bioengineering, Graduate School, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
- Chongqing University Jiangjin Hospital, School of Medicine, Chongqing University, No. 725 Jiangzhou Avenue, Dingshan Street, Jiangjin District, Chongqing 402260, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Faculty of Medical Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
| | - Yiguo Zhang
- Chongqing University Jiangjin Hospital, School of Medicine, Chongqing University, No. 725 Jiangzhou Avenue, Dingshan Street, Jiangjin District, Chongqing 402260, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Faculty of Medical Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing 400044, China
- Correspondence:
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Wufuer R, Fan Z, Liu K, Zhang Y. Differential Yet Integral Contributions of Nrf1 and Nrf2 in the Human HepG2 Cells on Antioxidant Cytoprotective Response against Tert-Butylhydroquinone as a Pro-Oxidative Stressor. Antioxidants (Basel) 2021; 10:antiox10101610. [PMID: 34679746 PMCID: PMC8533631 DOI: 10.3390/antiox10101610] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/30/2021] [Accepted: 10/05/2021] [Indexed: 12/30/2022] Open
Abstract
In the past 25 years, Nrf2 (nuclear factor erythroid 2-related factor 2, also called NFE2L2) had been preferentially parsed as a master hub of regulating antioxidant, detoxification, and cytoprotective genes; albeit as a matter of fact that Nrf1 (nuclear factor erythroid 2-related factor 1, also called NFE2L1)-rather than Nrf2-is indispensable for cell homeostasis and organ integrity during normal growth and development. Herein, distinct genotypic cell lines (i.e., Nrf1α-/-, Nrf2-/-ΔTA, and caNrf2ΔN) are employed to determine differential yet integral roles of Nrf1 and Nrf2 in mediating antioxidant responsive genes to tert-butylhydroquinone (tBHQ) serving as a pro-oxidative stressor. In Nrf1α-/- cells, Nrf2 was highly accumulated but also could not fully compensate specific loss of Nrf1α's function in its basal cytoprotective response against endogenous oxidative stress, though it exerted partially inducible antioxidant response, as the hormetic effect of tBHQ, against apoptotic damages. By contrast, Nrf2-/-ΔTA cells gave rise to a substantial reduction of Nrf1 in both basal and tBHQ-stimulated expression levels and hence resulted in obvious oxidative stress, but it can still be allowed to mediate a potent antioxidant response, as accompanied by a significantly decreased ratio of GSSG (oxidized glutathione) to GSH (reduced glutathione). Conversely, a remarkable increase of Nrf1 expression resulted from the constitutive active caNrf2ΔN cells, which were not manifested with oxidative stress, whether or not it was intervened with tBHQ. Such inter-regulatory effects of Nrf1 and Nrf2 on the antioxidant and detoxification genes (encoding HO-1, NQO1, GCLC, GCLM, GSR, GPX1, TALDO, MT1E, and MT2), as well on the ROS (reactive oxygen species)-scavenging activities of SOD (superoxide dismutase) and CAT (catalase), were further investigated. The collective results unraveled that Nrf1 and Nrf2 make distinctive yet cooperative contributions to finely tuning basal constitutive and/or tBHQ-inducible expression levels of antioxidant cytoprotective genes in the inter-regulatory networks. Overall, Nrf1 acts as a brake control for Nrf2's functionality to be confined within a certain extent, whilst its transcription is regulated by Nrf2.
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