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Alafate W, Lv G, Zheng J, Cai H, Wu W, Yang Y, Du S, Zhou D, Wang P. Targeting ARNT attenuates chemoresistance through destabilizing p38α-MAPK signaling in glioblastoma. Cell Death Dis 2024; 15:366. [PMID: 38806469 PMCID: PMC11133443 DOI: 10.1038/s41419-024-06735-1] [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: 01/06/2024] [Revised: 05/07/2024] [Accepted: 05/08/2024] [Indexed: 05/30/2024]
Abstract
Glioblastoma (GBM) is the most aggressive and lethal brain tumor in adults. This study aimed to investigate the functional significance of aryl hydrocarbon receptor nuclear translocator (ARNT) in the pathogenesis of GBM. Analysis of public datasets revealed ARNT is upregulated in GBM tissues compared to lower grade gliomas or normal brain tissues. Higher ARNT expression correlated with the mesenchymal subtype and poorer survival in GBM patients. Silencing ARNT using lentiviral shRNAs attenuated the proliferative, invasive, and stem-like capabilities of GBM cell lines, while ARNT overexpression enhanced these malignant phenotypes. Single-cell RNA sequencing uncovered that ARNT is highly expressed in a stem-like subpopulation and is involved in regulating glycolysis, hypoxia response, and stress pathways. Mechanistic studies found ARNT activates p38 mitogen-activated protein kinase (MAPK) signaling to promote chemoresistance in GBM cells. Disrupting the ARNT/p38α protein interaction via the ARNT PAS-A domain restored temozolomide sensitivity. Overall, this study demonstrates ARNT functions as an oncogenic driver in GBM pathogenesis and represents a promising therapeutic target.
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Affiliation(s)
- Wahafu Alafate
- Department of Neurosurgery, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China.
| | - Gen Lv
- Department of Neurosurgery, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Jiantao Zheng
- Department of Neurosurgery, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Haiping Cai
- Department of Neurosurgery, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Wei Wu
- Department of Neurosurgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
- Center of Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Yong Yang
- Department of Neurosurgery, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Shichao Du
- Department of Neurosurgery, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Dong Zhou
- Department of Neurosurgery, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Peng Wang
- Department of Neurosurgery, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China.
- Department of Neurosurgery, Heyuan People's Hospital, Heyuan, China.
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2
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Bi Y, Yang Q, Li Z, Wang Y, Wang Y, Jia A, Pan Z, Yang R, Liu G. Aryl hydrocarbon receptor nuclear translocator limits the recruitment and function of regulatory neutrophils against colorectal cancer by regulating the gut microbiota. J Exp Clin Cancer Res 2023; 42:53. [PMID: 36859266 PMCID: PMC9976387 DOI: 10.1186/s13046-023-02627-y] [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: 11/14/2022] [Accepted: 02/21/2023] [Indexed: 03/03/2023] Open
Abstract
BACKGROUND Although the role and mechanism of neutrophils in tumors have been widely studied, the precise effects of aryl hydrocarbon receptor nuclear translocator (ARNT) on neutrophils remain unclear. In this study, we investigated the roles of ARNT in the function of CD11b+Gr1+ neutrophils in colitis-associated colorectal cancer. METHODS Wild-type (WT), ARNT myeloid-specific deficient mice and a colitis-associated colorectal cancer mouse model were used in this study. The level and functions of CD11b+Gr1+ cells were evaluated by flow cytometry and confocal microscopy. RESULTS We found that ARNT deficiency drives neutrophils recruitment, neutrophil extracellular trap (NET) development, inflammatory cytokine secretion and suppressive activities when cells enter the periphery from bone marrow upon colorectal tumorigenesis. ARNT deficiency displays similar effects to aryl hydrocarbon receptor (AHR) deficiency in neutrophils. CXCR2 is required for NET development, cytokine production and recruitment of neutrophils but not the suppressive activities induced by Arnt-/- in colorectal cancer. The gut microbiota is essential for functional alterations in Arnt-/- neutrophils to promote colorectal cancer growth. The colorectal cancer effects of Arnt-/- neutrophils were significantly restored by mouse cohousing or antibiotic treatment. Intragastric administration of the feces of Arnt-/- mice phenocopied their colorectal cancer effects. CONCLUSION Our results defined a new role for the transcription factor ARNT in regulating neutrophils recruitment and function and the gut microbiota with implications for the future combination of gut microbiota and immunotherapy approaches in colorectal cancer.
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Affiliation(s)
- Yujing Bi
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 100071, Beijing, China.
| | - Qiuli Yang
- Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Zhengchao Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 100071, Beijing, China
| | - Yuexin Wang
- Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Yufei Wang
- Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Anna Jia
- Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Zhiyuan Pan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 100071, Beijing, China
| | - Ruifu Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 100071, Beijing, China
| | - Guangwei Liu
- Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China.
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3
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Gardella KA, Muro I, Fang G, Sarkar K, Mendez O, Wright CW. Aryl hydrocarbon receptor nuclear translocator (ARNT) isoforms control lymphoid cancer cell proliferation through differentially regulating tumor suppressor p53 activity. Oncotarget 2017; 7:10710-22. [PMID: 26909609 PMCID: PMC4905433 DOI: 10.18632/oncotarget.7539] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 01/22/2016] [Indexed: 12/25/2022] Open
Abstract
The aryl hydrocarbon receptor nuclear translocator (ARNT) is involved in xenobiotic and hypoxic responses, and we previously showed that ARNT also regulates nuclear factor-κB (NF-κB) signaling by altering the DNA binding activity of the RelB subunit. However, our initial study of ARNT-mediated RelB modulation was based on simultaneous suppression of the two ARNT isoforms, isoform 1 and 3, and precluded the examination of their individual functions. We find here that while normal lymphocytes harbor equal levels of isoform 1 and 3, lymphoid malignancies exhibit a shift to higher levels of ARNT isoform 1. These elevated levels of ARNT isoform 1 are critical to the proliferation of these cancerous cells, as suppression of isoform 1 in a human multiple myeloma (MM) cell line, and an anaplastic large cell lymphoma (ALCL) cell line, triggered S-phase cell cycle arrest, spontaneous apoptosis, and sensitized cells to doxorubicin treatment. Furthermore, co-suppression of RelB or p53 with ARNT isoform 1 prevented cell cycle arrest and blocked doxorubicin induced apoptosis. Together our findings reveal that certain blood cancers rely on ARNT isoform 1 to potentiate proliferation by antagonizing RelB and p53-dependent cell cycle arrest and apoptosis. Significantly, our results identify ARNT isoform 1 as a potential target for anticancer therapies.
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Affiliation(s)
- Kacie A Gardella
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, USA
| | - Israel Muro
- Division of Pharmacology and Toxicology, and The Center for Molecular and Cellular Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX, USA
| | - Gloria Fang
- Division of Pharmacology and Toxicology, and The Center for Molecular and Cellular Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX, USA
| | - Krishnakali Sarkar
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, USA
| | - Omayra Mendez
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, USA
| | - Casey W Wright
- Division of Pharmacology and Toxicology, and The Center for Molecular and Cellular Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX, USA.,Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, USA
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4
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Hsu SH, Wang LT, Chai CY, Wu CC, Hsi E, Chiou SS, Wang SN. Aryl hydrocarbon receptor promotes hepatocellular carcinoma tumorigenesis by targeting intestine-specific homeobox expression. Mol Carcinog 2017; 56:2167-2177. [PMID: 28398627 DOI: 10.1002/mc.22658] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 03/22/2017] [Accepted: 04/08/2017] [Indexed: 12/20/2022]
Abstract
The aryl hydrocarbon receptor (AHR), a major chemical sensor, is thought to play a role in various biological contexts, including cell cycle regulation and tumorigenesis. However, its regulatory mechanisms remain unclear. We propose herein a novel mechanism through which AHR promotes tumorigenesis by targeting expression of the oncogene intestine-specific homeobox (ISX) in hepatocellular carcinoma (HCC). Compared to paired tumor-adjacent tissues and non-HCC tumors, HCCs exhibited an increased and hierarchical pattern of AHR expression. Patients exhibiting high AHR expression had a significantly shorter survival duration, compared to those with low and medium expression. Functionally, AHR was found to target the newly discovered proto-oncogene, ISX, resulting in the increased expression of this gene and its downstream targets, CCND1 and E2F1. Ablation of AHR or ISX in hepatoma cells suppressed cell growth, whereas overexpression promoted cell proliferation and led to enhanced tumorigenic activity in vitro and in vivo. These results provide evidence to support a critical role for the AHR/ISX axis in HCC tumorigenesis and suggest its potential utility as a new therapeutic and prognostic target for HCC.
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Affiliation(s)
- Shih-Hsien Hsu
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.,Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Li-Ting Wang
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chee-Yin Chai
- Faculty of Medicine, Department of Pathology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chi-Cheng Wu
- Department of Business Management, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Edward Hsi
- Department of Medical Research, China Medical University Hospital, Taichung, Taiwan
| | - Shyh-Shin Chiou
- Faculty of Medicine, Department of Pediatrics, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Division of Hematology-Oncology, Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Shen-Nien Wang
- Division of Hepatobiliary Surgery, Department of Surgery, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Faculty of Medicine, Department of Surgery, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
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5
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A HIF-1α-driven feed-forward loop augments HIF signalling in Hep3B cells by upregulation of ARNT. Cell Death Dis 2016; 7:e2284. [PMID: 27362802 PMCID: PMC5108338 DOI: 10.1038/cddis.2016.187] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 06/01/2016] [Accepted: 06/03/2016] [Indexed: 02/07/2023]
Abstract
Oxygen-deprived (hypoxic) areas are commonly found within neoplasms caused by excessive cell proliferation. The transcription factor Aryl hydrocarbon receptor nuclear translocator (ARNT) is part of the hypoxia-inducible factor (HIF) pathway, which mediates adaptive responses to ensure cellular survival under hypoxic conditions. HIF signalling leads to metabolic alterations, invasion/metastasis and the induction of angiogenesis in addition to radio-chemoresistance of tumour cells. Activation of the HIF pathway is based on the abundance of HIF-α subunits, which are regulated in an oxygen-dependent manner and form transcriptional active complexes with ARNT or ARNT2 (also referred as HIF-1β and HIF-2β, respectively). ARNT is considered to be unaffected by hypoxia but certain cell lines, including Hep3B cells, are capable to elevate this transcription factor in response to oxygen deprivation, which implies an advantage. Therefore, the aim of this study was to elucidate the mechanism of hypoxia-dependent ARNT upregulation and to determine implications on HIF signalling. Gene silencing and overexpression techniques were used to alter the expression pattern of HIF transcription factors under normoxic and hypoxic conditions. qRT-PCR and western blotting were performed to measure gene and protein expression, respectively. HIF activity was determined by reporter gene assays. The results revealed a HIF-1α-dependent mechanism leading to ARNT upregulation in hypoxia. Forced expression of ARNT increased reporter activity under normoxic and hypoxic conditions. In conclusion, these findings indicate a novel feed-forward loop and suggest that ARNT might be a limiting factor. Augmented HIF signalling in terms of elevated target gene expression might be advantageous for tumour cells.
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6
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Huang CR, Lee CT, Chang KY, Chang WC, Liu YW, Lee JC, Chen BK. Down-regulation of ARNT promotes cancer metastasis by activating the fibronectin/integrin β1/FAK axis. Oncotarget 2016; 6:11530-46. [PMID: 25839165 PMCID: PMC4484474 DOI: 10.18632/oncotarget.3448] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 02/25/2015] [Indexed: 01/11/2023] Open
Abstract
The aryl hydrocarbon receptor nuclear translocator (ARNT) is broadly involved in regulating tumorigenesis by inducing genes that are involved in tumor growth and angiogenesis. Tumorigenesis usually involves normoxic conditions. However, the role of ARNT in tumor metastasis during normoxia remains unclear. Here, we demonstrate that ARNT protein levels were decreased in late-stage human colorectal cancer using immunohistochemical analysis. Down-regulation of ARNT protein promoted cancer cell migration and invasion, which was mediated by activation of the fibronectin/integrin β1/FAK signaling axis. In addition, the enhancement of migration and invasion in ANRT knockdown cells was blocked when ARNT was restored in the cells. In xenografts in severe combined immunodeficiency mice, tumor growth was significantly inhibited in the ARNT-knockdown condition. However, the tail-vein injection animal model revealed that the depletion of ARNT-induced metastatic lung colonies was further enhanced when ARNT expression was recovered post-injection. Interestingly, chemotherapeutic drugs inhibited ARNT expression and promoted the invasion of residual tumor cells. These results suggest that ARNT may play a positive role during tumor growth (either in early-stage tumor growth or in organ metastases), but plays a negative role in tumor migration and invasion. Therefore, the efficiency of ARNT-targeted therapy during different cancer stages should be carefully evaluated.
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Affiliation(s)
- Chi-Ruei Huang
- Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Taiwan, ROC.,Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taiwan, ROC
| | - Chung-Ta Lee
- Department of Pathology, National Cheng Kung University Hospital, Taiwan, ROC
| | - Kwang-Yu Chang
- National Institute of Cancer Research, National Health Research Institutes, Taiwan, ROC.,Division of Hematology/Oncology, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Taiwan, ROC
| | - Wen-Chang Chang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taiwan, ROC
| | - Yao-Wen Liu
- Department of Pathology, Kuo General Hospital, Taiwan, ROC
| | - Jenq-Chang Lee
- Department of Surgery, National Cheng Kung University Hospital, Taiwan, ROC
| | - Ben-Kuen Chen
- Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Taiwan, ROC.,Department of Pharmacology, College of Medicine, National Cheng Kung University, Taiwan, ROC.,Institute for Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taiwan, ROC
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7
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Mandl M, Lieberum MK, Dunst J, Depping R. The expression level of the transcription factor Aryl hydrocarbon receptor nuclear translocator (ARNT) determines cellular survival after radiation treatment. Radiat Oncol 2015; 10:229. [PMID: 26572229 PMCID: PMC4647475 DOI: 10.1186/s13014-015-0539-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 11/10/2015] [Indexed: 12/14/2022] Open
Abstract
Background Tumour hypoxia promotes radioresistance and is associated with poor prognosis. The transcription factor Aryl hydrocarbon receptor nuclear translocator (ARNT), also designated as Hypoxia-inducible factor (HIF)-1β, is part of the HIF pathway which mediates cellular adaptations to oxygen deprivation and facilitates tumour progression. The subunits HIF-1α and ARNT are key players within this pathway. HIF-1α is regulated in an oxygen-dependent manner whereas ARNT is considered to be constitutively expressed. However, there is mounting evidence that certain tumour cells are capable to elevate ARNT in hypoxia which suggests a survival benefit. Therefore the objective of this study was to elucidate effects of an altered ARNT expression level on the cellular response to radiation. Methods Different human cell lines (Hep3B, MCF-7, 786-Owt, 786-Ovhl, RCC4wt and RCC4vhl) originating from various tumour entities (Hepatocellular carcinoma, breast cancer and renal cell carcinoma respectively) were X-irradiated using a conventional linear accelerator. Knockdown of ARNT expression was achieved by transient siRNA transfection. Complementary experiments were performed by forced ARNT overexpression using appropriate plasmids. Presence/absence of ARNT protein was confirmed by Western blot analysis. Clonogenic survival assays were performed in order to determine cellular survival post irradiation. Statistical comparison of two groups was achieved by the unpaired t-test. Results The results of this study indicate that ARNT depletion renders tumour cells susceptible to radiation whereas overexpression of this transcription factor confers radioresistance. Conclusions These findings provide evidence to consider ARNT as a drug target and as a predictive marker in clinical applications concerning the response to radiation. Electronic supplementary material The online version of this article (doi:10.1186/s13014-015-0539-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Markus Mandl
- Institute of Physiology, Center for Structural and Cell Biology in Medicine, University of Luebeck, Ratzeburger Allee 160, 23562, Luebeck, Germany.
| | - Maria- Katharina Lieberum
- Institute of Physiology, Center for Structural and Cell Biology in Medicine, University of Luebeck, Ratzeburger Allee 160, 23562, Luebeck, Germany. .,Klinik für Strahlentherapie, Universitaetsklinikum Schleswig-Holstein, Campus Luebeck, Ratzeburger Allee 160, 23538, Luebeck, Germany.
| | - Juergen Dunst
- Klinik für Strahlentherapie, Universitaetsklinikum Schleswig-Holstein, Campus Luebeck, Ratzeburger Allee 160, 23538, Luebeck, Germany.
| | - Reinhard Depping
- Institute of Physiology, Center for Structural and Cell Biology in Medicine, University of Luebeck, Ratzeburger Allee 160, 23562, Luebeck, Germany.
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8
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Choi SH, Chung AR, Kang W, Park JY, Lee MS, Hwang SW, Kim DY, Kim SU, Ahn SH, Kim S, Han KH. Silencing of hypoxia-inducible factor-1β induces anti-tumor effects in hepatoma cell lines under tumor hypoxia. PLoS One 2014; 9:e103304. [PMID: 25068796 PMCID: PMC4113399 DOI: 10.1371/journal.pone.0103304] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 06/27/2014] [Indexed: 12/18/2022] Open
Abstract
Dimerization of hypoxia-inducible factor-1 beta (HIF-1β) [aryl hydrocarbon receptor nuclear translocator (ARNT)] with HIF-1α is involved in various aspects of cancer biology, including proliferation and survival under hypoxic conditions. We investigated the in vitro mechanism by which silencing of HIF-1β leads to the suppression of tumor cell growth and cellular functions. Various hepatocellular carcinoma (HCC) cell lines (Huh-7, Hep3B, and HepG2) were transfected with small interfering RNA (siRNA) against HIF-1β (siHIF-1β) and cultured under hypoxic conditions (1% O2 for 24 h). The expression levels of HIF-1β, HIF-1α, and growth factors were examined by immunoblotting. Tumor growth was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and tumor activity was measured by terminal deoxynucleotidyl transferase dUTP nick end labeling, tumor cell invasion, and migration assays. Under hypoxic conditions, silencing of HIF-1β expression suppressed tumor cell growth and regulated the expression of tumor growth-related factors, such as vascular endothelial growth factor, epidermal growth factor, and hepatocyte growth factor. Suppression of tumor cell invasion and migration was also demonstrated in HIF-1β-silenced HCC cell lines. Silencing of HIF-1β expression may induce anti-tumor effects under hypoxic conditions in HCC cell lines.
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Affiliation(s)
- Sung Hoon Choi
- Brain Korea 21 plus project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Ae Ri Chung
- Brain Korea 21 plus project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Wonseok Kang
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
- Yonsei Liver Cancer Special Clinic, Yonsei University Health System, Seoul, Korea
- Liver Cirrhosis Clinical Research Center, Yonsei University Health System, Seoul, Korea
| | - Jun Yong Park
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
- Yonsei Liver Cancer Special Clinic, Yonsei University Health System, Seoul, Korea
- Liver Cirrhosis Clinical Research Center, Yonsei University Health System, Seoul, Korea
| | - Mi Sol Lee
- Department of Premed, Yonsei University College of Medicine, Seoul, Korea
| | - Shin Won Hwang
- Department of Premed, Yonsei University College of Medicine, Seoul, Korea
| | - Do Young Kim
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
- Yonsei Liver Cancer Special Clinic, Yonsei University Health System, Seoul, Korea
- Liver Cirrhosis Clinical Research Center, Yonsei University Health System, Seoul, Korea
| | - Seung Up Kim
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
- Yonsei Liver Cancer Special Clinic, Yonsei University Health System, Seoul, Korea
- Liver Cirrhosis Clinical Research Center, Yonsei University Health System, Seoul, Korea
| | - Sang Hoon Ahn
- Brain Korea 21 plus project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
- Yonsei Liver Cancer Special Clinic, Yonsei University Health System, Seoul, Korea
- Liver Cirrhosis Clinical Research Center, Yonsei University Health System, Seoul, Korea
| | - Seungtaek Kim
- Brain Korea 21 plus project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
- Liver Cirrhosis Clinical Research Center, Yonsei University Health System, Seoul, Korea
| | - Kwang-Hyub Han
- Brain Korea 21 plus project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
- Yonsei Liver Cancer Special Clinic, Yonsei University Health System, Seoul, Korea
- Liver Cirrhosis Clinical Research Center, Yonsei University Health System, Seoul, Korea
- * E-mail:
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9
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Mandl M, Depping R. Hypoxia-inducible aryl hydrocarbon receptor nuclear translocator (ARNT) (HIF-1β): is it a rare exception? Mol Med 2014; 20:215-20. [PMID: 24849811 DOI: 10.2119/molmed.2014.00032] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 05/12/2014] [Indexed: 12/29/2022] Open
Abstract
The aryl hydrocarbon receptor nuclear translocator (ARNT), also designated as hypoxia-inducible factor (HIF)-1β, plays a pivotal role in the adaptive responses to (micro-)environmental stresses such as dioxin exposure and oxygen deprivation (hypoxia). ARNT belongs to the group of basic helix-loop-helix (bHLH)-Per-ARNT-Sim (PAS) transcription factors, which act as heterodimers. ARNT serves as a common binding partner for the aryl hydrocarbon receptor (AhR) as well as HIF-α subunits. HIF-α proteins are regulated in an oxygen-dependent manner, whereas ARNT is generally regarded as constitutively expressed, meaning that neither the arnt mRNA nor the protein level is influenced by hypoxia (despite the name HIF-1β). However, there is emerging evidence that tumor cells derived from different entities are able to upregulate ARNT, especially under low oxygen tension in a cell-specific manner. The objective of this review is therefore to highlight and summarize current knowledge regarding the hypoxia-dependent upregulation of ARNT, which is in sharp contrast to the general point of view described in the literature. Elucidating the mechanism behind this rare cellular attribute will help us to gain new insights into HIF biology and might provide new strategies for anti-cancer therapeutics. In conclusion, putative treatment effects on ARNT should be taken into account while studying the HIF pathway. This step is of great importance when ARNT is intended to serve as a loading control or as a reference.
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Affiliation(s)
- Markus Mandl
- University of Lübeck, Center for Structural and Cell Biology in Medicine, Institute of Physiology, Lübeck, Germany
| | - Reinhard Depping
- University of Lübeck, Center for Structural and Cell Biology in Medicine, Institute of Physiology, Lübeck, Germany
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10
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Chan YY, Kalpana S, Chang WC, Chang WC, Chen BK. Expression of aryl hydrocarbon receptor nuclear translocator enhances cisplatin resistance by upregulating MDR1 expression in cancer cells. Mol Pharmacol 2013; 84:591-602. [PMID: 23907215 DOI: 10.1124/mol.113.087197] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The identification of molecular pathways in cancer cells is important for understanding the cells' underlying biology and for designing effective cancer therapies. We demonstrate that the expression of aryl hydrocarbon receptor nuclear translocator (ARNT) is critical during the development of cisplatin resistance. The reduced expression of ARNT was correlated with cisplatin-induced cell death in drug-sensitive cells. In addition, suppression of ARNT reversed the characteristics of cisplatin-resistant cells, making these cells cisplatin-sensitive, and significantly enhanced caspase-3 activation, DNA fragmentation, and apoptosis. The inhibition of colony formation, regulated by cisplatin, was more significant in ARNT-knockdown cells than in parental cells. In a xenograft analysis of severe combined immunodeficiency mice, cisplatin also efficiently inhibited ARNT-deficient c4 tumors but not ARNT-containing vT2 tumor formation. Furthermore, the downregulation of multidrug resistance 1 (MDR1) expression and retention of drugs in cells caused by suppression of ARNT, resulting in the resensitization of drug-resistant cells to cisplatin, was observed. When overexpressed, ARNT interacted with Sp1 to enhance the expression of MDR1 through Sp1-binding sites on the MDR1 promoter, resulting in a reversal of the effect of cisplatin on cell death. In addition, ARNT-induced MDR1 expression was inhibited in Sp1-knockdown cells. These results reveal previously unrecognized, multifaceted functions of ARNT in establishing the drug-resistant properties of cancer cells by the upregulation of MDR1, highlighting ARNT's potential as a therapeutic target in an important subset of cancers.
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Affiliation(s)
- Ya-Yi Chan
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan (Y.-Y.C., S.K., B.-K.C.); Department of Clinical Pharmacology and Master Program for Clinical Pharmacogenomics and Pharmacoproteomics, School of Pharmacology, Taipei Medical University, Taipei, Taiwan (W.-Chi.C.); Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan (W.-Cha.C.); Department of Pharmacy, Taipei Medical University-Wanfang Hospital, Taipei, Taiwan (W.-Chi.C.); and Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan (B.-K.C.)
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