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Raicu AM, Suresh M, Arnosti DN. A regulatory role for the unstructured C-terminal domain of the CtBP transcriptional corepressor. J Biol Chem 2024; 300:105490. [PMID: 38000659 PMCID: PMC10788531 DOI: 10.1016/j.jbc.2023.105490] [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: 07/07/2023] [Revised: 10/31/2023] [Accepted: 11/09/2023] [Indexed: 11/26/2023] Open
Abstract
The C-terminal binding protein (CtBP) is a transcriptional corepressor that plays critical roles in development, tumorigenesis, and cell fate. CtBP proteins are structurally similar to alpha hydroxyacid dehydrogenases and feature a prominent intrinsically disordered region in the C terminus. In the mammalian system, CtBP proteins lacking the C-terminal domain (CTD) are able to function as transcriptional regulators and oligomerize, putting into question the significance of this unstructured domain for gene regulation. Yet, the presence of an unstructured CTD of ∼100 residues, including some short motifs, is conserved across Bilateria, indicating the importance of maintaining this domain over evolutionary time. To uncover the significance of the CtBP CTD, we functionally tested naturally occurring Drosophila isoforms of CtBP that possess or lack the CTD, namely CtBP(L) and CtBP(S). We used the CRISPRi system to recruit dCas9-CtBP(L) and dCas9-CtBP(S) to endogenous promoters to directly compare their transcriptional impacts in vivo. Interestingly, CtBP(S) was able to significantly repress transcription of the Mpp6 promoter, while CtBP(L) was much weaker, suggesting that the long CTD may modulate CtBP's repression activity. In contrast, in cell culture, the isoforms behaved similarly on a transfected Mpp6 reporter gene. The context-specific differences in activity of these two developmentally regulated isoforms suggests that the CTD may help provide a spectrum of repression activity suitable for developmental programs.
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Affiliation(s)
- Ana-Maria Raicu
- Cell and Molecular Biology Program, Michigan State University, East Lansing, Michigan, USA
| | - Megha Suresh
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - David N Arnosti
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA.
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Chougoni KK, Park H, Damle PK, Mason T, Cheng B, Dcona MM, Szomju B, Dozmorov MG, Idowu MO, Grossman SR. Coordinate transcriptional regulation of ErbB2/3 by C-terminal binding protein 2 signals sensitivity to ErbB2 inhibition in pancreatic adenocarcinoma. Oncogenesis 2023; 12:53. [PMID: 37949862 PMCID: PMC10638350 DOI: 10.1038/s41389-023-00498-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 10/22/2023] [Accepted: 10/27/2023] [Indexed: 11/12/2023] Open
Abstract
There is a critical need to identify new therapeutic vulnerabilities in pancreatic ductal adenocarcinoma (PDAC). Transcriptional co-regulators C-terminal binding proteins (CtBP) 1 and 2 are highly overexpressed in human PDAC, and CRISPR-based homozygous deletion of Ctbp2 in a mouse PDAC cell line (CKP) dramatically decreased tumor growth, reduced metastasis, and prolonged survival in orthotopic mouse allografts. Transcriptomic profiling of tumors derived from CKP vs. Ctbp2-deleted CKP cells (CKP/KO) revealed significant downregulation of the EGFR-superfamily receptor Erbb3, the heterodimeric signaling partner for both EGFR and ErbB2. Compared with CKP cells, CKP/KO cells also demonstrated reduced Erbb2 expression and did not activate downstream Akt signaling after stimulation of Erbb3 by its ligand neuregulin-1. ErbB3 expression in human PDAC cell lines was similarly dependent on CtBP2 and depletion of ErbB3 in a human PDAC cell line severely attenuated growth, demonstrating the critical role of ErbB3 signaling in maintaining PDAC cell growth. Sensitivity to the ErbB2-targeted tyrosine kinase inhibitor lapatinib, but not the EGFR-targeted agent erlotinib, varied in proportion to the level of ErbB3 expression in mouse and human PDAC cells, suggesting that an ErBb2 inhibitor can effectively leverage CtBP2-driven transcriptional activation of physiologic ErbB2/3 expression and signaling in PDAC cells for therapeutic benefit.
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Affiliation(s)
- Kranthi Kumar Chougoni
- Keck School of Medicine and USC Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, 90033, USA
| | - Haemin Park
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Priyadarshan K Damle
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Travis Mason
- Department of Surgery, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Bo Cheng
- Keck School of Medicine and USC Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, 90033, USA
| | - Martin M Dcona
- Keck School of Medicine and USC Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, 90033, USA
| | - Barbara Szomju
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Mikhail G Dozmorov
- Department of Biostatistics, Virginia Commonwealth University, Richmond, VA, 23298, USA
- VCU Massey Comprehensive Cancer Center, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Michael O Idowu
- VCU Massey Comprehensive Cancer Center, Virginia Commonwealth University, Richmond, VA, 23298, USA
- Department of Pathology, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Steven R Grossman
- Keck School of Medicine and USC Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, 90033, USA.
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Raicu AM, Suresh M, Arnosti DN. A regulatory role for the unstructured C-terminal domain of the CtBP transcriptional corepressor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.19.541472. [PMID: 37292674 PMCID: PMC10245716 DOI: 10.1101/2023.05.19.541472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The C-terminal Binding Protein (CtBP) is a transcriptional corepressor that plays critical roles in development, tumorigenesis, and cell fate. CtBP proteins are structurally similar to alpha hydroxyacid dehydrogenases and feature a prominent intrinsically disordered region in the C-terminus. In the mammalian system, CtBP proteins lacking the C-terminal Domain (CTD) are able to function as transcriptional regulators and oligomerize, putting into question the significance of this unstructured domain for gene regulation. Yet, the presence of an unstructured CTD of ~100 residues, including some short motifs, is conserved across Bilateria, indicating the importance of maintaining this domain over evolutionary time. To uncover the significance of the CtBP CTD, we functionally tested naturally occurring Drosophila isoforms of CtBP that possess or lack the CTD, namely CtBP(L) and CtBP(S). We used the CRISPRi system to recruit dCas9-CtBP(L) and dCas9-CtBP(S) to endogenous promoters to directly compare their transcriptional impacts in vivo. Interestingly, CtBP(S) was able to significantly repress transcription of the Mpp6 promoter, while CtBP(L) was much weaker, suggesting that the long CTD may modulate CtBP's repression activity. In contrast, in cell culture, the isoforms behaved similarly on a transfected Mpp6 reporter gene. The context-specific differences in activity of these two developmentally-regulated isoforms suggests that the CTD may help provide a spectrum of repression activity suitable for developmental programs.
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Affiliation(s)
- Ana-Maria Raicu
- Cell and Molecular Biology Program, Michigan State University, East Lansing, MI
| | - Megha Suresh
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI
| | - David N Arnosti
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI
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Dcona MM, Chougoni KK, Dcona DT, West JL, Singh SJ, Ellis KC, Grossman SR. Combined Targeting of NAD Biosynthesis and the NAD-dependent Transcription Factor C-terminal Binding Protein as a Promising Novel Therapy for Pancreatic Cancer. CANCER RESEARCH COMMUNICATIONS 2023; 3:2003-2013. [PMID: 37707363 PMCID: PMC10549224 DOI: 10.1158/2767-9764.crc-22-0521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 08/07/2023] [Accepted: 09/06/2023] [Indexed: 09/15/2023]
Abstract
Cancer therapies targeting metabolic derangements unique to cancer cells are emerging as a key strategy to address refractory solid tumors such as pancreatic ductal adenocarcinomas (PDAC) that exhibit resistance to extreme nutrient deprivation in the tumor microenvironment. Nicotinamide adenine dinucleotide (NAD) participates in multiple metabolic pathways and nicotinamide phosphoribosyl transferase (NAMPT) is one of the key intracellular enzymes that facilitate the synthesis of NAD. C-terminal binding proteins 1 and 2 (CtBP) are paralogous NAD-dependent oncogenic transcription factors and dehydrogenases that nucleate an epigenetic complex regulating a cohort of genes responsible for cancer proliferation and metastasis. As adequate intracellular NAD is required for CtBP to oligomerize and execute its oncogenic transcriptional coregulatory activities, we hypothesized that NAD depletion would synergize with CtBP inhibition, improving cell inhibitory efficacy. Indeed, depletion of cellular NAD via the NAMPT inhibitor GMX1778 enhanced growth inhibition induced by either RNAi-mediated CtBP1/2 knockdown or the CtBP dehydrogenase inhibitor 4-chlorophenyl-2-hydroxyimino propanoic acid as much as 10-fold in PDAC cells, while untransformed pancreatic ductal cells were unaffected. The growth inhibitory effects of the NAMPT/CtBP inhibitor combination correlated pharmacodynamically with on-target disruption of CtBP1/2 dimerization, CtBP2 interaction with the CoREST epigenetic regulator, and transcriptional activation of the oncogenic target gene TIAM1. Moreover, this same therapeutic combination strongly attenuated growth of PDAC cell line xenografts in immunodeficient mice, with no observable toxicity. Collectively, our data demonstrate that targeting CtBP in combination with NAD depletion represents a promising therapeutic strategy for PDAC. SIGNIFICANCE Effective precision therapies are lacking in PDAC. We demonstrate that simultaneous inhibition of NAD metabolism and the oncoprotein CtBP is potently effective at blocking growth of both PDAC cells in culture and human PDAC-derived tumors in mice and should be explored further as a potential therapy for patients with PDAC.
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Affiliation(s)
- M. Michael Dcona
- USC Norris Comprehensive Cancer Center and Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Kranthi Kumar Chougoni
- USC Norris Comprehensive Cancer Center and Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Diana T. Dcona
- USC Norris Comprehensive Cancer Center and Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Jacqueline L. West
- Department of Medicinal Chemistry and Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia
| | - Sahib J. Singh
- VCU Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia
| | - Keith C. Ellis
- Department of Medicinal Chemistry and Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia
- VCU Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia
| | - Steven R. Grossman
- USC Norris Comprehensive Cancer Center and Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
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Xu X, Liu Y, Hu H, Wang J, Cai Y, Xie J, Kang M, He F. Relationship between cancer stem cell-related SNPs and survival outcomes in patients with primary lung cancer. World J Surg Oncol 2023; 21:243. [PMID: 37563730 PMCID: PMC10416443 DOI: 10.1186/s12957-023-03064-z] [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: 03/21/2023] [Accepted: 06/04/2023] [Indexed: 08/12/2023] Open
Abstract
BACKGROUND Cancer stem cells may be the source of cancer-causing mutant cells and are closely related to the prognosis of cancer. Our study aimed to investigate the potential association between single-nucleotide polymorphisms (SNPs) of cancer stem cell-related genes and the prognosis of lung cancer patients. METHODS The SNP loci were genotyped by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS), and the overall survival of subjects was analyzed by log-rank test after stratifying and adjusting their demographic data, clinical data, and genotypes. The correlation between survival time and quality of life of lung cancer under codominant, dominant, recessive, and additive genetic models was analyzed by the Cox regression model. The association between SNP polymorphism and the prognosis of lung cancer was analyzed by Stata16.0 software, and their heterogeneity was tested. Interaction analysis was performed using R software (version 4.2.0). RESULTS Stratified analysis unveiled that rs3740535 had recessive AA genotype and additive GG genotype; Rs3130932 dominant GT + GG genotype, additive TT genotype; Rs13409 additive TT genotype; Rs6815391 recessive CC genotype and additional TT genotype were associated with increased risk of lung cancer death. Rs3130932 recessive GG genotype was associated with a reduced risk of lung cancer death. CONCLUSION Rs3740535, rs3130932, rs13409, and rs6815391 are associated with the overall survival of lung cancer patients and may be valuable for the prognosis of lung cancer patients.
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Affiliation(s)
- Xinying Xu
- Department of Epidemiology and Health Statistics, School of Public Health, Fujian Medical University, Fuzhou, China
| | - Yuhang Liu
- Department of Epidemiology and Health Statistics, School of Public Health, Fujian Medical University, Fuzhou, China
| | - Huiyi Hu
- Department of Labor Health, School of Public Health, China Medical University, Shenyang, China
| | - Jinshen Wang
- Department of Venereal Disease Prevention, Dermatology Hospital, Southern Medical University, Guangzhou, China
| | - Yuxin Cai
- Department of Health Toxicology, School of Public Health, Xiamen University, Xiamen, China
| | - Jun Xie
- Sanming Dermatology Hospital, Sanming, China
| | - Mingqiang Kang
- Department of Thoracic Surgery, Fujian Medical University Union Hospital, Fuzhou, China.
| | - Fei He
- Department of Epidemiology and Health Statistics, School of Public Health, Fujian Medical University, Fuzhou, China.
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Tan M, Pan Q, Wu Q, Li J, Wang J. Aldolase B attenuates clear cell renal cell carcinoma progression by inhibiting CtBP2. Front Med 2023; 17:503-517. [PMID: 36790589 DOI: 10.1007/s11684-022-0947-9] [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: 01/12/2022] [Accepted: 06/28/2022] [Indexed: 02/16/2023]
Abstract
Aldolase B (ALDOB), a glycolytic enzyme, is uniformly depleted in clear cell renal cell carcinoma (ccRCC) tissues. We previously showed that ALDOB inhibited proliferation through a mechanism independent of its enzymatic activity in ccRCC, but the mechanism was not unequivocally identified. We showed that the corepressor C-terminal-binding protein 2 (CtBP2) is a novel ALDOB-interacting protein in ccRCC. The CtBP2-to-ALDOB expression ratio in clinical samples was correlated with the expression of CtBP2 target genes and was associated with shorter survival. ALDOB inhibited CtBP2-mediated repression of multiple cell cycle inhibitor, proapoptotic, and epithelial marker genes. Furthermore, ALDOB overexpression decreased the proliferation and migration of ccRCC cells in an ALDOB-CtBP2 interaction-dependent manner. Mechanistically, our findings showed that ALDOB recruited acireductone dioxygenase 1, which catalyzes the synthesis of an endogenous inhibitor of CtBP2, 4-methylthio 2-oxobutyric acid. ALDOB functions as a scaffold to bring acireductone dioxygenase and CtBP2 in close proximity to potentiate acireductone dioxygenase-mediated inhibition of CtBP2, and this scaffolding effect was independent of ALDOB enzymatic activity. Moreover, increased ALDOB expression inhibited tumor growth in a xenograft model and decreased lung metastasis in vivo. Our findings reveal that ALDOB is a negative regulator of CtBP2 and inhibits tumor growth and metastasis in ccRCC.
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Affiliation(s)
- Mingyue Tan
- Department of Urology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China
- Urology Center, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Qi Pan
- Department of Urology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China
| | - Qi Wu
- Department of Urology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China
- Department of Urology, The Sixth Affiliated Hospital of Wenzhou Medical University (The People's Hospital of Lishui), Lishui, 323000, China
| | - Jianfa Li
- Department of Urology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China
| | - Jun Wang
- Department of Urology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China.
- Urology Center, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
- Department of Urology, The Sixth Affiliated Hospital of Wenzhou Medical University (The People's Hospital of Lishui), Lishui, 323000, China.
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Zhu XM, Tan Y, Shi YH, Li Q, Zhu J, Liu XD, Tong QZ. TMT-based quantitative proteomics analysis of the effects of Jiawei Danshen decoction myocardial ischemia-reperfusion injury. Proteome Sci 2022; 20:17. [PMID: 36517846 PMCID: PMC9749149 DOI: 10.1186/s12953-022-00200-7] [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: 08/02/2022] [Accepted: 11/30/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Every year, approximately 17 million people worldwide die due to coronary heart disease, with China ranking second in terms of the death toll. Myocardial ischemia-reperfusion injury (MIRI) significantly influences cardiac function and prognosis in cardiac surgery patients. Jiawei Danshen Decoction (JWDSD) is a traditional Chinese herbal prescription that has been used clinically for many years in China to treat MIRI. The underlying molecular mechanisms, however, remain unknown. To investigate the proteomic changes in myocardial tissue of rats given JWDSD for MIRI therapy-based proteomics. METHODS MIRI rat model was created by ligating/releasing the left anterior descending coronary artery. For seven days, the drugs were administered twice daily. The model was created following the last drug administration. JWDSD's efficacy in improving MIRI was evaluated using biochemical markers and cardiac histology. Tandem mass tag-based quantitative proteomics (TMT) technology was also used to detect proteins in the extracted heart tissue. To analyze differentially expressed proteins (DEPs), bioinformatics analysis, including gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathways, were employed. Furthermore, western blotting confirmed the potential targets regulated by JWDSD. RESULTS The histopathologic characteristics and biochemical data showed JWDSD's protective effects on MIRI rats. A total of 4549 proteins were identified with FDR (false discovery rate) ≤1%. Twenty overlapping were identified (162 DEPs and 45 DEPs in Model/Control or JWDSD/Model group, respectively). Of these DEPs, 16 were regulated by JWDSD. GO analysis provided a summary of the deregulated protein expression in the categories of biological process (BP), cell component (CC), and molecular function (MF). KEGG enrichment analysis revealed that the signaling pathways of neutrophil extracellular trap formation, RNA polymerase, serotonergic synapse, and linoleic acid metabolism are all closely related to JWDSD effects in MIRI rats. Furthermore, T-cell lymphoma invasion and metastasis 1 (TIAM1) was validated using western blotting, and the results were consistent with proteomics data. CONCLUSIONS Our study suggests that JWDSD may exert therapeutic effects through multi-pathways regulation in MIRI treatment. This work may provide proteomics clues for continuing research on JWDSD in treating MIRI.
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Affiliation(s)
- Xiang-Mei Zhu
- grid.488482.a0000 0004 1765 5169Pharmacy of College, Hunan University of Chinese Medicine, Xueshi Road, Number 300, Changsha, Hunan 410208, People’s Republic of China ,grid.67293.39The Second Hospital of Hunan University of Chinese Medicine, Caie North Road, Number 233, Changsha, Hunan 410005, People’s Republic of China
| | - Yang Tan
- grid.488482.a0000 0004 1765 5169Pharmacy of College, Hunan University of Chinese Medicine, Xueshi Road, Number 300, Changsha, Hunan 410208, People’s Republic of China
| | - Yu-He Shi
- grid.488482.a0000 0004 1765 5169Pharmacy of College, Hunan University of Chinese Medicine, Xueshi Road, Number 300, Changsha, Hunan 410208, People’s Republic of China
| | - Qing Li
- grid.488482.a0000 0004 1765 5169Pharmacy of College, Hunan University of Chinese Medicine, Xueshi Road, Number 300, Changsha, Hunan 410208, People’s Republic of China
| | - Jue Zhu
- grid.488482.a0000 0004 1765 5169Pharmacy of College, Hunan University of Chinese Medicine, Xueshi Road, Number 300, Changsha, Hunan 410208, People’s Republic of China
| | - Xiang-Dan Liu
- grid.488482.a0000 0004 1765 5169Pharmacy of College, Hunan University of Chinese Medicine, Xueshi Road, Number 300, Changsha, Hunan 410208, People’s Republic of China ,Key Laboratory of Germplasm Resources and Standardized Planting of Bulk Authentic Medicinal Materials from Hunan, Xueshi Road, Number 300, Changsha, Hunan 410208, People’s Republic of China
| | - Qiao-Zhen Tong
- grid.488482.a0000 0004 1765 5169Pharmacy of College, Hunan University of Chinese Medicine, Xueshi Road, Number 300, Changsha, Hunan 410208, People’s Republic of China ,Key Laboratory of Germplasm Resources and Standardized Planting of Bulk Authentic Medicinal Materials from Hunan, Xueshi Road, Number 300, Changsha, Hunan 410208, People’s Republic of China
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C-terminal binding protein 2 promotes high-glucose-triggered cell proliferation, angiogenesis and cellular adhesion of human retinal endothelial cell line. Int Ophthalmol 2022; 42:2975-2985. [PMID: 35353294 DOI: 10.1007/s10792-022-02283-9] [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: 10/21/2021] [Accepted: 03/12/2022] [Indexed: 10/18/2022]
Abstract
PURPOSE The proliferation and angiogenesis of human retinal endothelial cells (HRECs) are critical for the pathophysiology of diabetic retinopathy (DR). C-terminal binding protein 2 (CtBP2) has multiple biologic functions, but its effect on HRECs under high-glucose (HG) conditions is unclear. METHODS The cell viability, angiogenesis, cellular adhesion and CtBP2 expression levels of HRECs were measured following treatment with different concentrations of glucose. Small interfering CtBP2-targeting RNA, wide-type and function mutant plasmid of CtBP2 were constructed and then were transfected into HRECs to evaluate the effects of CtBP2 on cell functions of HRECs. RESULTS The expression of CtBP2 in HRECs was increased after HG treatment. HG treatment significantly increased cell proliferation, angiogenesis, and decreased relative gene expressions in gap junctions, tight junctions and adherens junctions. After CtBP2 was inhibited via siRNA, the changes induced by HG were partially restored. Conversely, only wild-type CtBP2 could increase cell proliferation and angiogenesis under HG condition. Mechanistically, we also found that CtBP2 exerted its functions to effect HG-induced changes via Akt signaling pathway. CONCLUSION This study implicates that CtBP2 promotes HG-induced cell proliferation, angiogenesis and cellular adhesion, and CtBP2 might be a potential target in the prevention of DR.
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The transrepression and transactivation roles of CtBPs in the pathogenesis of different diseases. J Mol Med (Berl) 2021; 99:1335-1347. [PMID: 34196767 DOI: 10.1007/s00109-021-02107-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/31/2021] [Accepted: 06/25/2021] [Indexed: 02/06/2023]
Abstract
Gene transcription is strictly controlled by transcriptional complexes, which are assemblies of transcription factors, transcriptional regulators, and co-regulators. Mammalian genomes encode two C-terminal-binding proteins (CtBPs), CtBP1 and CtBP2, which are both well-known transcriptional corepressors of oncogenic processes. Their overexpression in tumors is associated with malignant behavior, such as uncontrolled cell proliferation, migration, and invasion, as well as with an increase in the epithelial-mesenchymal transition. CtBPs coordinate with other transcriptional regulators, such as histone deacetylases (HDACs) and histone acetyltransferases (p300 and CBP [CREBP-binding protein]) that contain the PXDLS motif, and with transcription factors to assemble transcriptional complexes that dock onto the promoters of genes to initiate gene transcription. Emerging evidence suggests that CtBPs function as both corepressors and coactivators in different biological processes ranging from apoptosis to inflammation and osteogenesis. Therapeutic targeting of CtBPs or the interactions required to form transcriptional complexes has also shown promising effects in preventing disease progression. This review summarizes the most recent progress in the study of CtBP functions and therapeutic inhibitors in different biological processes. This knowledge may enable a better understanding of the complexity of the roles of CtBPs, while providing new insights into therapeutic strategies that target CtBPs.
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10
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Endoplasmic reticulum stress regulates the intestinal stem cell state through CtBP2. Sci Rep 2021; 11:9892. [PMID: 33972635 PMCID: PMC8111031 DOI: 10.1038/s41598-021-89326-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 04/09/2021] [Indexed: 02/06/2023] Open
Abstract
Enforcing differentiation of cancer stem cells is considered as a potential strategy to sensitize colorectal cancer cells to irradiation and chemotherapy. Activation of the unfolded protein response, due to endoplasmic reticulum (ER) stress, causes rapid stem cell differentiation in normal intestinal and colon cancer cells. We previously found that stem cell differentiation was mediated by a Protein kinase R-like ER kinase (PERK) dependent arrest of mRNA translation, resulting in rapid protein depletion of WNT-dependent transcription factor c-MYC. We hypothesize that ER stress dependent stem cell differentiation may rely on the depletion of additional transcriptional regulators with a short protein half-life that are rapidly depleted due to a PERK-dependent translational pause. Using a novel screening method, we identify novel transcription factors that regulate the intestinal stem cell fate upon ER stress. ER stress was induced in LS174T cells with thapsigargin or subtilase cytotoxin (SubAB) and immediate alterations in nuclear transcription factor activity were assessed by the CatTFRE assay in which transcription factors present in nuclear lysate are bound to plasmid DNA, co-extracted and quantified using mass-spectrometry. The role of altered activity of transcription factor CtBP2 was further examined by modification of its expression levels using CAG-rtTA3-CtBP2 overexpression in small intestinal organoids, shCtBP2 knockdown in LS174T cells, and familial adenomatous polyposis patient-derived organoids. CtBP2 overexpression organoids were challenged by ER stress and ionizing irradiation. We identified a unique set of transcription factors with altered activation upon ER stress. Gene ontology analysis showed that transcription factors with diminished binding were involved in cellular differentiation processes. ER stress decreased CtBP2 protein expression in mouse small intestine. ER stress induced loss of CtBP2 expression which was rescued by inhibition of PERK signaling. CtBP2 was overexpressed in mouse and human colorectal adenomas. Inducible CtBP2 overexpression in organoids conferred higher clonogenic potential, resilience to irradiation-induced damage and a partial rescue of ER stress-induced loss of stemness. Using an unbiased proteomics approach, we identified a unique set of transcription factors for which DNA-binding activity is lost directly upon ER stress. We continued investigating the function of co-regulator CtBP2, and show that CtBP2 mediates ER stress-induced loss of stemness which supports the intestinal stem cell state in homeostatic stem cells and colorectal cancer cells.
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11
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Nichols JC, Schiffer CA, Royer WE. NAD(H) phosphates mediate tetramer assembly of human C-terminal binding protein (CtBP). J Biol Chem 2021; 296:100351. [PMID: 33524397 PMCID: PMC7949142 DOI: 10.1016/j.jbc.2021.100351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/22/2021] [Accepted: 01/27/2021] [Indexed: 12/27/2022] Open
Abstract
C-terminal binding proteins (CtBPs) are cotranscriptional factors that play key roles in cell fate. We have previously shown that NAD(H) promotes the assembly of similar tetramers from either human CtBP1 and CtBP2 and that CtBP2 tetramer destabilizing mutants are defective for oncogenic activity. To assist structure-based design efforts for compounds that disrupt CtBP tetramerization, it is essential to understand how NAD(H) triggers tetramer assembly. Here, we investigate the moieties within NAD(H) that are responsible for triggering tetramer formation. Using multiangle light scattering (MALS), we show that ADP is able to promote tetramer formation of both CtBP1 and CtBP2, whereas AMP promotes tetramer assembly of CtBP1, but not CtBP2. Other NAD(H) moieties that lack the adenosine phosphate, including adenosine and those incorporating nicotinamide, all fail to promote tetramer assembly. Our crystal structures of CtBP1 with AMP reveal participation of the adenosine phosphate in the tetrameric interface, pinpointing its central role in NAD(H)-linked assembly. CtBP1 and CtBP2 have overlapping but unique roles, suggesting that a detailed understanding of their unique structural properties might have utility in the design of paralog-specific inhibitors. We investigated the different responses to AMP through a series of site-directed mutants at 13 positions. These mutations reveal a central role for a hinge segment, which we term the 120s hinge that connects the substrate with coenzyme-binding domains and influences nucleotide binding and tetramer assembly. Our results provide insight into suitable pockets to explore in structure-based drug design to interfere with cotranscriptional activity of CtBP in cancer.
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Affiliation(s)
- Jeffry C Nichols
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA; Chemistry Department, Worcester State University, Worcester, Massachusetts, USA
| | - Celia A Schiffer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - William E Royer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
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12
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Vijayalingam S, Ezekiel UR, Xu F, Subramanian T, Geerling E, Hoelscher B, San K, Ganapathy A, Pemberton K, Tycksen E, Pinto AK, Brien JD, Beck DB, Chung WK, Gurnett CA, Chinnadurai G. Human iPSC-Derived Neuronal Cells From CTBP1-Mutated Patients Reveal Altered Expression of Neurodevelopmental Gene Networks. Front Neurosci 2020; 14:562292. [PMID: 33192249 PMCID: PMC7653094 DOI: 10.3389/fnins.2020.562292] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 10/01/2020] [Indexed: 11/17/2022] Open
Abstract
A recurrent de novo mutation in the transcriptional corepressor CTBP1 is associated with neurodevelopmental disabilities in children (Beck et al., 2016, 2019; Sommerville et al., 2017). All reported patients harbor a single recurrent de novo heterozygous missense mutation (p.R342W) within the cofactor recruitment domain of CtBP1. To investigate the transcriptional activity of the pathogenic CTBP1 mutant allele in physiologically relevant human cell models, we generated induced pluripotent stem cells (iPSC) from the dermal fibroblasts derived from patients and normal donors. The transcriptional profiles of the iPSC-derived “early” neurons were determined by RNA-sequencing. Comparison of the RNA-seq data of the neurons from patients and normal donors revealed down regulation of gene networks involved in neurodevelopment, synaptic adhesion and anti-viral (interferon) response. Consistent with the altered gene expression patterns, the patient-derived neurons exhibited morphological and electrophysiological abnormalities, and susceptibility to viral infection. Taken together, our studies using iPSC-derived neuron models provide novel insights into the pathological activities of the CTBP1 p.R342W allele.
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Affiliation(s)
- S Vijayalingam
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Edward A. Doisy Research Center, St. Louis, MO, United States
| | - Uthayashanker R Ezekiel
- Department of Clinical Health Sciences, Doisy College of Health Science, Saint Louis University School of Medicine, Saint Louis, MO, United States
| | - Fenglian Xu
- Department of Biology and Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University, St. Louis, MO, United States
| | - T Subramanian
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Edward A. Doisy Research Center, St. Louis, MO, United States
| | - Elizabeth Geerling
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Edward A. Doisy Research Center, St. Louis, MO, United States
| | - Brittany Hoelscher
- Department of Biology and Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University, St. Louis, MO, United States
| | - KayKay San
- Department of Clinical Health Sciences, Doisy College of Health Science, Saint Louis University School of Medicine, Saint Louis, MO, United States
| | - Aravinda Ganapathy
- Department of Clinical Health Sciences, Doisy College of Health Science, Saint Louis University School of Medicine, Saint Louis, MO, United States
| | - Kyle Pemberton
- Department of Biology and Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University, St. Louis, MO, United States
| | - Eric Tycksen
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, United States
| | - Amelia K Pinto
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Edward A. Doisy Research Center, St. Louis, MO, United States
| | - James D Brien
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Edward A. Doisy Research Center, St. Louis, MO, United States
| | - David B Beck
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Wendy K Chung
- Department of Pediatrics and Medicine, Columbia University Medical Center, New York, NY, United States
| | - Christina A Gurnett
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, United States
| | - G Chinnadurai
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Edward A. Doisy Research Center, St. Louis, MO, United States
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13
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Zeng J, Chen JY, Meng J, Chen Z. Inflammation and DNA methylation coregulate the CtBP-PCAF-c-MYC transcriptional complex to activate the expression of a long non-coding RNA CASC2 in acute pancreatitis. Int J Biol Sci 2020; 16:2116-2130. [PMID: 32549759 PMCID: PMC7294942 DOI: 10.7150/ijbs.43557] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Accepted: 04/20/2020] [Indexed: 02/06/2023] Open
Abstract
Long non-coding RNAs (lncRNAs) are emerging as important regulators involved in the pathogenesis of many diseases. However, it is still unknown if they contribute to the occurrence of acute pancreatitis (AP). Here, we identified a lncRNA CASC2 (Cancer Susceptibility Candidate 2) was significantly upregulated in the pancreatic tissues from AP patients. Knockdown or overexpression of CASC2 in vitro could specifically repress or induce the expression of two proinflammatory cytokines including IL6 (Interleukin 6) and IL17, respectively. Changing the expression levels of several transcription factors that were predicted to bind to the promoter of CASC2, we found c-MYC could specifically regulate the expression of CASC2. Using immunoprecipitation, mass spectrometry, and co-immunoprecipitation assays, we proved that c-MYC assembled a transcriptional complex with PCAF (p300/CBP-associated Factor) and CtBP1/2 (C-terminal Binding Protein 1 and 2), terming as the CtBP-PCAF-c-MYC (CPM) complex. Further investigation revealed that CtBPs were amplified in the pancreatic tissues from AP patients and they functioned as coactivators to induce the expression of CASC2 and thus led to the upregulation of IL6 and IL17. Moreover, we identified that decreased DNA methylation levels in the promoters of CtBPs and inflammatory stimuli coactivated the expression of CtBPs. Collectively, we identified a new signaling pathway in which DNA methylation and inflammatory stimuli coregulate the CPM complex to activate CASC2 expression, whose induction further activates the expression of IL6 and IL17, eventually aggravating inflammation response and causing the pathology of AP.
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Affiliation(s)
- Jun Zeng
- Department of Gastroenterology, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang, Jiangxi, China
| | - Jian-Yong Chen
- Department of Gastroenterology, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang, Jiangxi, China
| | - Jun Meng
- Department of Gastroenterology, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang, Jiangxi, China
| | - Zhi Chen
- Department of critical care medicine, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang, Jiangxi, China.,Department of Pulmonary and Critical Care Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
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14
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Li H, Zhang C, Yang C, Blevins M, Norris D, Zhao R, Huang M. C-terminal binding proteins 1 and 2 in traumatic brain injury-induced inflammation and their inhibition as an approach for anti-inflammatory treatment. Int J Biol Sci 2020; 16:1107-1120. [PMID: 32174788 PMCID: PMC7053329 DOI: 10.7150/ijbs.42109] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 12/29/2019] [Indexed: 01/10/2023] Open
Abstract
Traumatic brain injury (TBI) induces an acute inflammatory response in the central nervous system that involves both resident and peripheral immune cells. The ensuing chronic neuroinflammation causes cell death and tissue damage and may contribute to neurodegeneration. The molecular mechanisms involved in the maintenance of this chronic inflammation state remain underexplored. C-terminal binding protein (CtBP) 1 and 2 are transcriptional coregulators that repress diverse cellular processes. Unexpectedly, we find that the CtBPs can transactivate a common set of proinflammatory genes both in lipopolysaccharide-activated microglia, astrocytes and macrophages, and in a mouse model of the mild form of TBI. We also find that the expression of these genes is markedly enhanced by a single mild injury in both brain and peripheral blood leukocytes in a severity- and time-dependent manner. Moreover, we were able to demonstrate that specific inhibitors of the CtBPs effectively suppress the expression of the CtBP target genes and thus improve neurological outcome in mice receiving single and repeated mild TBIs. This discovery suggests new avenues for therapeutic modulation of the inflammatory response to brain injury.
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Affiliation(s)
- Hong Li
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora CO 80045, USA
| | - Caiguo Zhang
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora CO 80045, USA
| | - Chunxia Yang
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora CO 80045, USA
- Department of Psychiatry, First Hospital of Shanxi Medical University, Taiyuan, China
| | - Melanie Blevins
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora CO 80045, USA
| | - David Norris
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora CO 80045, USA
| | - Rui Zhao
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora CO 80045, USA
| | - Mingxia Huang
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora CO 80045, USA
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15
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Sun X, Xiao L, Chen J, Chen X, Chen X, Yao S, Li H, Zhao G, Ma J. DNA methylation is involved in the pathogenesis of osteoarthritis by regulating CtBP expression and CtBP-mediated signaling. Int J Biol Sci 2020; 16:994-1009. [PMID: 32140068 PMCID: PMC7053340 DOI: 10.7150/ijbs.39945] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 12/26/2019] [Indexed: 12/12/2022] Open
Abstract
Osteoarthritis (OA) is a common type of arthritis. Chronic inflammation is an important contributor to the pathogenesis of OA. The maturation and secretion of proinflammatory cytokines are controlled by inflammasomes, especially NLRP1 (NLR Family Pyrin Domain Containing 1) and NLRP3. In this study, we identified a transactivation mechanism of NLRP3 mediated by CtBPs (C-terminal-binding proteins). We found that both the mRNA and protein levels of CtBPs were significantly increased in OA biopsies. Analyzing the profiles of differentially expressed genes in CtBP-knockdown and overexpression cells, we found that the expression of NLRP3 was dependent on CtBP levels. By the knockdown or overexpression of transcription factors that potentially bind to the promoter of NLRP3, we found that only AP1 could specifically regulate the expression of NLRP3. Using immunoprecipitation (IP) and Co-IP assays, we found that AP1 formed a transcriptional complex with a histone acetyltransferase p300 and CtBPs. The knockdown of any member of this transcriptional complex resulted in a decrease in the expression of NLRP3. To explore the underlying mechanism of CtBP overexpression, we analyzed their promoters and found that they were abundant in CpG islands. Treatment with the DNA methylation inhibitor 5-aza-2′-deoxycytidine (AZA) or knockdown of DNMTs (DNA methyltransferases) resulted in the overexpression of CtBPs, while overexpression of DNMTs caused the reverse effects on CtBP expression. Collectively, our results suggest that the decreased DNA methylation levels in the promoters of CtBPs upregulate their expression. Increased CtBPs associated with p300 and AP1 to form a transcriptional complex and activate the expression of NLRP3 and its downstream signaling, eventually aggravating the inflammatory response and leading to the pathogenesis of OA.
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Affiliation(s)
- Xiangxiang Sun
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an 710054, Shaanxi, China
| | - Lin Xiao
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an 710054, Shaanxi, China
| | - Juan Chen
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an 710054, Shaanxi, China
| | - Xun Chen
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an 710054, Shaanxi, China
| | - Xinlin Chen
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an 710054, Shaanxi, China
| | - Shuxin Yao
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an 710054, Shaanxi, China
| | - Hui Li
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an 710054, Shaanxi, China
| | - Guanghui Zhao
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an 710054, Shaanxi, China
| | - Jianbing Ma
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an 710054, Shaanxi, China
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16
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Zhou P, Wan X, Zou Y, Chen Z, Zhong A. Transforming growth factor beta (TGF-β) is activated by the CtBP2-p300-AP1 transcriptional complex in chronic renal failure. Int J Biol Sci 2020; 16:204-215. [PMID: 31929749 PMCID: PMC6949151 DOI: 10.7150/ijbs.38841] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 10/15/2019] [Indexed: 12/17/2022] Open
Abstract
Chronic renal failure (CRF), also known as chronic kidney disease (CKD), is a common renal disorder characterized by gradual kidney dysfunction. Molecular dissection reveals that transforming growth factor beta (TGF-β) plays a central role in the pathogenesis of CRF. However, the mechanism underlying TGF-β upregulation has not been demonstrated. Here, we verified that the elevated level of TGF-β was associated with the severity of CRF stages and the activation of TGF-β-mediated signaling in 120 renal biopsies from CRF patients. By analyzing the promoter region of the TGFB1 gene, we identified one AP-1 (activator protein 1) and four NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) binding sites. Knockdown of two AP-1 subunits (c-Jun and c-FOS) or blockage of AP-1 signaling with two inhibitors T-5224 and SR11302 could cause the downregulation of TGFB1, whereas knockdown of two NF-κB subunits (p65 and p50) or blockage of NF-κB signaling with two inhibitors TPCA1 and BOT-64 could not change the expression of TGFB1. Using mass spectrometry and coimmunoprecipitation analyses, we found that both c-Jun and c-FOS formed a complex with CtBP2 (C-terminal binding protein 2) and histone acetyltransferase p300. Our in vitro data demonstrated that induction of CtBP2 by recombinant IL-1β (interleukin-1 beta) led to the upregulation of TGFB1 and the activation of TGF-β downstream signaling, while knockdown of CtBP2 resulted in the reversed effects. Using chromatin immunoprecipitation assays, we revealed that the CtBP2-p300-AP1 complex specifically bound to the promoter of TGFB and that knockdown or blockage of CtBP2 significantly decreased the occupancies of the p300 and AP-1 subunits. Our results support a model in which the CtBP2-p300-AP1 transcriptional complex activates the expression of TGFB1, increasing its production and extracellular secretion. The secreted TGF-β binds to its receptors and initiates downstream signaling.
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Affiliation(s)
- Ping Zhou
- Department of Nephrology, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang 330006, Jiangxi, China
| | - Xiaoxiao Wan
- Department of Nephrology, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang 330006, Jiangxi, China
| | - Yan Zou
- Department of Nephrology, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang 330006, Jiangxi, China
| | - Zhi Chen
- Department of Critical Care Medicine, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang 330006, Jiangxi, China
| | - Aimin Zhong
- Department of Nephrology, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang 330006, Jiangxi, China
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17
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Chen Z, Dong WH, Chen Q, Li QG, Qiu ZM. Downregulation of miR-199a-3p mediated by the CtBP2-HDAC1-FOXP3 transcriptional complex contributes to acute lung injury by targeting NLRP1. Int J Biol Sci 2019; 15:2627-2640. [PMID: 31754335 PMCID: PMC6854378 DOI: 10.7150/ijbs.37133] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 08/27/2019] [Indexed: 02/07/2023] Open
Abstract
Emerging evidence indicates that microRNAs (miRNAs) play fundamental roles in the pathogenesis of multiple diseases, including acute lung injury (ALI). Here, we discovered that miR-199a-3p was significantly downregulated in ALI lung tissues using a microarray analysis. In vitro lipopolysaccharide (LPS) treatment of the human epithelial cell line A549 and the human macrophage cell line U937 caused a decrease of miR-199a-3p. Mechanically, miR-199a-3p specifically bound to the 3'-untranslated region (3'-UTR) of NLRP1 (nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing protein 1), a critical member of inflammasomes. Ectopic overexpression or downregulation of miR-199a-3p resulted in the repression or induction of NLRP1, respectively, thereby downregulating or activating its downstream events. Moreover, transcription factor FOXP3 (forkhead box P3) was able to specifically bind to the promoter of miR-199a-3p. Knockdown or overexpression of FOXP3 resulted in a decrease or induction miR-199a-3p expression, respectively. Using immunoprecipitation (IP), mass spectrometry and co-IP assays, we found that FOXP3 formed a transcriptional complex with HDAC1 (histone deacetylase 1) and CtBP2 (C-terminal-binding protein 2). Collectively, our results suggested that the CtBP2-HDAC1-FOXP3 transcriptional complex (CHFTC) could specifically bind to the promoter of miR-199a-3p and repress its expression. Downregulation of miR-199a-3p eliminated its inhibition of NLRP1, causing activation of NLRP1 and cleavage of pro-IL-1β and pro-IL-18 mediated by Caspase-1. The secretion of IL-1β and IL-18 further aggravated the inflammatory response and resulted in the occurrence of ALI.
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Affiliation(s)
- Zhi Chen
- Department of Pulmonary and Critical Care Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China.,Department of Critical Care Medicine, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang 330006, Jiangxi, China
| | - Wei-Hua Dong
- Department of Critical Care Medicine, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang 330006, Jiangxi, China
| | - Qiang Chen
- Department of Pulmonary and Critical Care Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Qiu-Gen Li
- Department of Pulmonary and Critical Care Medicine, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang 330006, Jiangxi, China
| | - Zhong-Min Qiu
- Department of Pulmonary and Critical Care Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
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18
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Beck DB, Subramanian T, Vijayalingam S, Ezekiel UR, Donkervoort S, Yang ML, Dubbs HA, Ortiz-Gonzalez XR, Lakhani S, Segal D, Au M, Graham JM, Verma S, Waggoner D, Shinawi M, Bönnemann CG, Chung WK, Chinnadurai G. A pathogenic CtBP1 missense mutation causes altered cofactor binding and transcriptional activity. Neurogenetics 2019; 20:129-143. [PMID: 31041561 DOI: 10.1007/s10048-019-00578-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 03/18/2019] [Accepted: 04/09/2019] [Indexed: 11/29/2022]
Abstract
We previously reported a pathogenic de novo p.R342W mutation in the transcriptional corepressor CTBP1 in four independent patients with neurodevelopmental disabilities [1]. Here, we report the clinical phenotypes of seven additional individuals with the same recurrent de novo CTBP1 mutation. Within this cohort, we identified consistent CtBP1-related phenotypes of intellectual disability, ataxia, hypotonia, and tooth enamel defects present in most patients. The R342W mutation in CtBP1 is located within a region implicated in a high affinity-binding cleft for CtBP-interacting proteins. Unbiased proteomic analysis demonstrated reduced interaction of several chromatin-modifying factors with the CtBP1 W342 mutant. Genome-wide transcriptome analysis in human glioblastoma cell lines expressing -CtBP1 R342 (wt) or W342 mutation revealed changes in the expression profiles of genes controlling multiple cellular processes. Patient-derived dermal fibroblasts were found to be more sensitive to apoptosis during acute glucose deprivation compared to controls. Glucose deprivation strongly activated the BH3-only pro-apoptotic gene NOXA, suggesting a link between enhanced cell death and NOXA expression in patient fibroblasts. Our results suggest that context-dependent relief of transcriptional repression of the CtBP1 mutant W342 allele may contribute to deregulation of apoptosis in target tissues of patients leading to neurodevelopmental phenotypes.
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Affiliation(s)
- David B Beck
- National Human Genome Research Institute, National Institutes of Health, 10 Center Drive, Room B3-4129, Bethesda, MD, 20892, USA
| | - T Subramanian
- Institute for Molecular Virology, Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, E. A. Doisy Research Center, 6th Floor, St. Louis, MO, 63104, USA
| | - S Vijayalingam
- Institute for Molecular Virology, Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, E. A. Doisy Research Center, 6th Floor, St. Louis, MO, 63104, USA
| | - Uthayashankar R Ezekiel
- Clinical Health Sciences, Saint Louis University, 3437 Caroline Street, Allied Health Building, Suite 3025, Saint Louis, MO, 63104, USA
| | - Sandra Donkervoort
- National Institute of Neurological Disorders and Stroke Neurogenetics Branch, National Institutes of Health, 10 Center Drive Room 2B39, MSC 1477, Bethesda, MD, 20892, USA
| | - Michele L Yang
- University of Colorado Denver, 13123 E. 16th Ave; Box B155, Aurora, CO, 80238, USA
| | - Holly A Dubbs
- Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Xilma R Ortiz-Gonzalez
- Department of Neurology, Pereleman School of Medicine, University of Pennsylvania; Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Shenela Lakhani
- Center for Neurogenetics, Brain and Mind Research Institute, Weill Cornell Medicine, 413 E 69th Street, New York, NY, 10021, USA
| | - Devorah Segal
- Department of Pediatrics, Division of Child Neurology, Weill Cornell Medicine, 525 E. 68th St, Box 91, New York, NY, 10065, USA
| | - Margaret Au
- Medical Genetics, Department of Pediatrics, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90068, USA
| | - John M Graham
- Medical Genetics, Department of Pediatrics, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90068, USA
| | - Sumit Verma
- Division of Pediatric Neurology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Darrel Waggoner
- Department of Human Genetics, University of Chicago, Chicago, IL, 60637, USA
| | - Marwan Shinawi
- Department of Pediatrics, Division of Genetics and Genomic Medicine,, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Carsten G Bönnemann
- National Institute of Neurological Disorders and Stroke Neurogenetics Branch, National Institutes of Health, 10 Center Drive Room 2B39, MSC 1477, Bethesda, MD, 20892, USA
| | - Wendy K Chung
- Departments of Pediatrics and Medicine, Columbia University Medical Center, New York, NY, USA.
| | - G Chinnadurai
- Institute for Molecular Virology, Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, E. A. Doisy Research Center, 6th Floor, St. Louis, MO, 63104, USA.
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19
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Dcona MM, Damle PK, Zarate-Perez F, Morris BL, Nawaz Z, Dennis MJ, Deng X, Korwar S, Singh SJ, Ellis KC, Royer WE, Bandyopadhyay D, Escalante C, Grossman SR. Active-Site Tryptophan, the Target of Antineoplastic C-Terminal Binding Protein Inhibitors, Mediates Inhibitor Disruption of CtBP Oligomerization and Transcription Coregulatory Activities. Mol Pharmacol 2019; 96:99-108. [PMID: 31036695 DOI: 10.1124/mol.118.114363] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 04/21/2019] [Indexed: 01/20/2023] Open
Abstract
C-terminal binding proteins (CtBP1/2) are oncogenic transcriptional coregulators and dehydrogenases often overexpressed in multiple solid tumors, including breast, colon, and ovarian cancer, and associated with poor survival. CtBPs act by repressing expression of genes responsible for apoptosis (e.g., PUMA, BIK) and metastasis-associated epithelial-mesenchymal transition (e.g., CDH1), and by activating expression of genes that promote migratory and invasive properties of cancer cells (e.g., TIAM1) and genes responsible for enhanced drug resistance (e.g., MDR1). CtBP's transcriptional functions are also critically dependent on oligomerization and nucleation of transcriptional complexes. Recently, we have developed a family of CtBP dehydrogenase inhibitors, based on the parent 2-hydroxyimino-3-phenylpropanoic acid (HIPP), that specifically disrupt cancer cell viability, abrogate CtBP's transcriptional function, and block polyp formation in a mouse model of intestinal polyposis that depends on CtBP's oncogenic functions. Crystallographic analysis revealed that HIPP interacts with CtBP1/2 at a conserved active site tryptophan (W318/324; CtBP1/2) that is unique among eukaryotic D2-dehydrogenases. To better understand the mechanism of action of HIPP-class inhibitors, we investigated the contribution of W324 to CtBP2's biochemical and physiologic activities utilizing mutational analysis. Indeed, W324 was necessary for CtBP2 self-association, as shown by analytical ultracentrifugation and in vivo cross-linking. Additionally, W324 supported CtBP's association with the transcriptional corepressor CoREST, and was critical for CtBP2 induction of cell motility. Notably, the HIPP derivative 4-chloro-HIPP biochemically and biologically phenocopied mutational inactivation of CtBP2 W324. Our data support further optimization of W318/W324-interacting CtBP dehydrogenase inhibitors that are emerging as a novel class of cancer cell-specific therapeutic.
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Affiliation(s)
- M Michael Dcona
- Departments of Internal Medicine (M.M.D., P.K.D., Z.N., M.J.D., S.J.S., S.R.G.), Human and Molecular Genetics (B.L.M., S.R.G.), Physiology and Biophysics (F.Z.-P., C.E.), Medicinal Chemistry (S.K., K.C.E.), and Biostatistics (X.D., D.B.) and Massey Cancer Center (K.C.E., D.B., C.E., S.R.G.), Virginia Commonwealth University, Richmond, Virginia; and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (W.E.R.)
| | - Priyadarshan K Damle
- Departments of Internal Medicine (M.M.D., P.K.D., Z.N., M.J.D., S.J.S., S.R.G.), Human and Molecular Genetics (B.L.M., S.R.G.), Physiology and Biophysics (F.Z.-P., C.E.), Medicinal Chemistry (S.K., K.C.E.), and Biostatistics (X.D., D.B.) and Massey Cancer Center (K.C.E., D.B., C.E., S.R.G.), Virginia Commonwealth University, Richmond, Virginia; and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (W.E.R.)
| | - Francisco Zarate-Perez
- Departments of Internal Medicine (M.M.D., P.K.D., Z.N., M.J.D., S.J.S., S.R.G.), Human and Molecular Genetics (B.L.M., S.R.G.), Physiology and Biophysics (F.Z.-P., C.E.), Medicinal Chemistry (S.K., K.C.E.), and Biostatistics (X.D., D.B.) and Massey Cancer Center (K.C.E., D.B., C.E., S.R.G.), Virginia Commonwealth University, Richmond, Virginia; and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (W.E.R.)
| | - Benjamin L Morris
- Departments of Internal Medicine (M.M.D., P.K.D., Z.N., M.J.D., S.J.S., S.R.G.), Human and Molecular Genetics (B.L.M., S.R.G.), Physiology and Biophysics (F.Z.-P., C.E.), Medicinal Chemistry (S.K., K.C.E.), and Biostatistics (X.D., D.B.) and Massey Cancer Center (K.C.E., D.B., C.E., S.R.G.), Virginia Commonwealth University, Richmond, Virginia; and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (W.E.R.)
| | - Zaid Nawaz
- Departments of Internal Medicine (M.M.D., P.K.D., Z.N., M.J.D., S.J.S., S.R.G.), Human and Molecular Genetics (B.L.M., S.R.G.), Physiology and Biophysics (F.Z.-P., C.E.), Medicinal Chemistry (S.K., K.C.E.), and Biostatistics (X.D., D.B.) and Massey Cancer Center (K.C.E., D.B., C.E., S.R.G.), Virginia Commonwealth University, Richmond, Virginia; and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (W.E.R.)
| | - Michael J Dennis
- Departments of Internal Medicine (M.M.D., P.K.D., Z.N., M.J.D., S.J.S., S.R.G.), Human and Molecular Genetics (B.L.M., S.R.G.), Physiology and Biophysics (F.Z.-P., C.E.), Medicinal Chemistry (S.K., K.C.E.), and Biostatistics (X.D., D.B.) and Massey Cancer Center (K.C.E., D.B., C.E., S.R.G.), Virginia Commonwealth University, Richmond, Virginia; and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (W.E.R.)
| | - Xiaoyan Deng
- Departments of Internal Medicine (M.M.D., P.K.D., Z.N., M.J.D., S.J.S., S.R.G.), Human and Molecular Genetics (B.L.M., S.R.G.), Physiology and Biophysics (F.Z.-P., C.E.), Medicinal Chemistry (S.K., K.C.E.), and Biostatistics (X.D., D.B.) and Massey Cancer Center (K.C.E., D.B., C.E., S.R.G.), Virginia Commonwealth University, Richmond, Virginia; and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (W.E.R.)
| | - Sudha Korwar
- Departments of Internal Medicine (M.M.D., P.K.D., Z.N., M.J.D., S.J.S., S.R.G.), Human and Molecular Genetics (B.L.M., S.R.G.), Physiology and Biophysics (F.Z.-P., C.E.), Medicinal Chemistry (S.K., K.C.E.), and Biostatistics (X.D., D.B.) and Massey Cancer Center (K.C.E., D.B., C.E., S.R.G.), Virginia Commonwealth University, Richmond, Virginia; and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (W.E.R.)
| | - Sahib J Singh
- Departments of Internal Medicine (M.M.D., P.K.D., Z.N., M.J.D., S.J.S., S.R.G.), Human and Molecular Genetics (B.L.M., S.R.G.), Physiology and Biophysics (F.Z.-P., C.E.), Medicinal Chemistry (S.K., K.C.E.), and Biostatistics (X.D., D.B.) and Massey Cancer Center (K.C.E., D.B., C.E., S.R.G.), Virginia Commonwealth University, Richmond, Virginia; and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (W.E.R.)
| | - Keith C Ellis
- Departments of Internal Medicine (M.M.D., P.K.D., Z.N., M.J.D., S.J.S., S.R.G.), Human and Molecular Genetics (B.L.M., S.R.G.), Physiology and Biophysics (F.Z.-P., C.E.), Medicinal Chemistry (S.K., K.C.E.), and Biostatistics (X.D., D.B.) and Massey Cancer Center (K.C.E., D.B., C.E., S.R.G.), Virginia Commonwealth University, Richmond, Virginia; and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (W.E.R.)
| | - William E Royer
- Departments of Internal Medicine (M.M.D., P.K.D., Z.N., M.J.D., S.J.S., S.R.G.), Human and Molecular Genetics (B.L.M., S.R.G.), Physiology and Biophysics (F.Z.-P., C.E.), Medicinal Chemistry (S.K., K.C.E.), and Biostatistics (X.D., D.B.) and Massey Cancer Center (K.C.E., D.B., C.E., S.R.G.), Virginia Commonwealth University, Richmond, Virginia; and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (W.E.R.)
| | - Dipankar Bandyopadhyay
- Departments of Internal Medicine (M.M.D., P.K.D., Z.N., M.J.D., S.J.S., S.R.G.), Human and Molecular Genetics (B.L.M., S.R.G.), Physiology and Biophysics (F.Z.-P., C.E.), Medicinal Chemistry (S.K., K.C.E.), and Biostatistics (X.D., D.B.) and Massey Cancer Center (K.C.E., D.B., C.E., S.R.G.), Virginia Commonwealth University, Richmond, Virginia; and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (W.E.R.)
| | - Carlos Escalante
- Departments of Internal Medicine (M.M.D., P.K.D., Z.N., M.J.D., S.J.S., S.R.G.), Human and Molecular Genetics (B.L.M., S.R.G.), Physiology and Biophysics (F.Z.-P., C.E.), Medicinal Chemistry (S.K., K.C.E.), and Biostatistics (X.D., D.B.) and Massey Cancer Center (K.C.E., D.B., C.E., S.R.G.), Virginia Commonwealth University, Richmond, Virginia; and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (W.E.R.)
| | - Steven R Grossman
- Departments of Internal Medicine (M.M.D., P.K.D., Z.N., M.J.D., S.J.S., S.R.G.), Human and Molecular Genetics (B.L.M., S.R.G.), Physiology and Biophysics (F.Z.-P., C.E.), Medicinal Chemistry (S.K., K.C.E.), and Biostatistics (X.D., D.B.) and Massey Cancer Center (K.C.E., D.B., C.E., S.R.G.), Virginia Commonwealth University, Richmond, Virginia; and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (W.E.R.)
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20
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CtBP promotes metastasis of breast cancer through repressing cholesterol and activating TGF-β signaling. Oncogene 2018; 38:2076-2091. [PMID: 30442980 DOI: 10.1038/s41388-018-0570-z] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 10/19/2018] [Accepted: 10/26/2018] [Indexed: 02/06/2023]
Abstract
Metastasis is the process through which the primary cancer cells spread beyond the primary tumor and disseminate to other organs. Most cancer patients die of metastatic disease. EMT is proposed to be the initial event associated with cancer metastasis and how it occurred is still a mystery. CtBP is known as a co-repressor abundantly expressed in many types of cancer and regulates genes involved in cancer initiation, progression, and metastasis. We found that CtBP regulates intracellular cholesterol homeostasis in breast cancer cells by forming a complex with ZEB1 and transcriptionally repressing SREBF2 expression. Importantly, CtBP repression of intracellular cholesterol abundance leads to increased EMT and cell migration. The reason is that cholesterol negatively regulates the stability of TGF-β receptors on the cell membrane. Interestingly, TGF-β is also capable of reducing intracellular cholesterol relying on the increased recruitment of ZEB1 and CtBP complex to SREBF2 promoter. Thus, we propose a feedback loop formed by CtBP, cholesterol, and TGF-β signaling pathway, through which TGF-β triggers the cascade that mobilizes the cancer cells for metastasis. Consistently, the intravenous injection of breast cancer cells with ectopically CtBP expression show increased lung metastasis depending on the reduction of intracellular cholesterol. Finally, we analyzed the public breast cancer datasets and found that CtBP expression negatively correlates with SREBF2 and HMGCR expressions. High expression of CtBP and low expression of SREBF2 and HMGCR significantly correlates with high EMT of the primary tumors.
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21
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Zhang W, Duan N, Zhang Q, Song T, Li Z, Chen X, Wang K. The intracellular NADH level regulates atrophic nonunion pathogenesis through the CtBP2-p300-Runx2 transcriptional complex. Int J Biol Sci 2018; 14:2023-2036. [PMID: 30585266 PMCID: PMC6299368 DOI: 10.7150/ijbs.28302] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 10/05/2018] [Indexed: 12/03/2022] Open
Abstract
Atrophic nonunion, a complicated failure of fracture healing, is still obscure regarding its molecular pathological mechanisms. Carboxyl-terminal binding proteins (CtBPs), an NADH-sensitive transcriptional corepressor family, are involved in many diseases, such as cancer and inflammation. Here, we found that CtBP2, but not CtBP1, was significantly overexpressed in atrophic nonunion tissues compared to healthy controls. Using a mass spectrometry assay, we found that CtBP2 can form a complex with histone acetyltransferase p300 and transcription factor Runx2. The lower NADH level in atrophic nonunion tissues disrupted CtBP2 dimerization and enhanced the blockage of the accessibility of the p300-Runx2 complex to the promoters of a series of bone-related target genes, such as OSC, ALPL, COL1A1, IBSP, SPP1 and MMP13. The expression of these genes can be reversed by a forced increase in NADH with CoCl2 treatment. In conclusion, our study revealed that NADH levels determine the expression of bone formation and development of related genes through affecting the dissociation or binding of CtBP2 to the p300-Runx2 complex. These results represent a conserved mechanism, by which CtBP2 serves as a NADH-dependent repressor of the p300-Runx2 transcriptional complex and thus affects bone formation.
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Affiliation(s)
- Wentao Zhang
- Department of Orthopedics, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710005, Shaanxi, China.,Department of Orthopaedics, Hong-Hui Hospital, Xi'an Jiaotong University, Xi'an 710054, Shaanxi, China
| | - Ning Duan
- Department of Orthopaedics, Hong-Hui Hospital, Xi'an Jiaotong University, Xi'an 710054, Shaanxi, China
| | - Qian Zhang
- The second department of surgery room, Shaanxi Provincial Tumor Hospital, Xi'an 710061, Shaanxi, China
| | - Tao Song
- Department of Orthopaedics, Hong-Hui Hospital, Xi'an Jiaotong University, Xi'an 710054, Shaanxi, China
| | - Zhong Li
- Department of Orthopaedics, Hong-Hui Hospital, Xi'an Jiaotong University, Xi'an 710054, Shaanxi, China
| | - Xun Chen
- Department of Orthopaedics, Hong-Hui Hospital, Xi'an Jiaotong University, Xi'an 710054, Shaanxi, China
| | - Kunzheng Wang
- Department of Orthopedics, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710005, Shaanxi, China
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22
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An intestinal stem cell niche in Apc mutated neoplasia targetable by CtBP inhibition. Oncotarget 2018; 9:32408-32418. [PMID: 30197752 PMCID: PMC6126694 DOI: 10.18632/oncotarget.25784] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Accepted: 06/19/2018] [Indexed: 12/18/2022] Open
Abstract
C-terminal binding protein 2 (CtBP2) drives intestinal polyposis in the Apcmin mouse model of human Familial Adenomatous Polyposis. As CtBP2 is targetable by an inhibitor of its dehydrogenase domain, understanding CtBP2’s role in adenoma formation is necessary to optimize CtBP-targeted therapies in Apc mutated human neoplasia. Tumor initiating cell (TIC) populations were substantially decreased in ApcminCtbp2+/- intestinal epithelia. Moreover, normally nuclear Ctbp2 was mislocalized to the cytoplasm of intestinal crypt stem cells in Ctbp2+/- mice, both Apcmin and wildtype, correlating with low/absent CD133 expression in those cells, and possibly explaining the lower burden of polyps in Apcmin Ctbp2+/- mice. The CtBP inhibitor 4-chloro-hydroxyimino phenylpyruvate (4-Cl-HIPP) also robustly downregulated TIC populations and significantly decreased intestinal polyposis in Apcmin mice. We have therefore demonstrated a critical link between polyposis, intestinal TIC’s and Ctbp2 gene dosage or activity, supporting continued efforts targeting CtBP in the treatment or prevention of Apc mutated neoplasia.
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23
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Du K, Zhang X, Lou Z, Guo P, Zhang F, Wang B, Chen L, Zhang C. MicroRNA485-3p negatively regulates the transcriptional co-repressor CtBP1 to control the oncogenic process in osteosarcoma cells. Int J Biol Sci 2018; 14:1445-1456. [PMID: 30262996 PMCID: PMC6158736 DOI: 10.7150/ijbs.26335] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 07/08/2018] [Indexed: 12/31/2022] Open
Abstract
Carboxyl-terminal binding protein 1 (CtBP1), a well-known transcriptional co-repressor, is highly expressed in a number of cancer types. However, it is still absent in osteosarcoma cells. Here, we found that CtBP1, but not CtBP2, is overexpressed in invasive osteosarcoma tissues and cells. The overexpressed CtBP1 in turn represses its downstream targets, such as the pro-apoptotic regulators Bax, Bim and p53 upregulated modulator of apoptosis (PUMA), cell adhesion molecule E-cadherin, and the cell cycle regulators p16, p21 and phosphatase and tensin homolog (PTEN). To explore the molecular mechanism of CtBP1 overexpression, we subjected three independent clinical samples to miRNA microarray analysis and found that miR-485-3p could specifically bind to the 3'-untranslated region (3'-UTR) of CtBP1, thereby negatively controlling CtBP1 expression. The overexpression of miR-485-3p in osteosarcoma cells significantly repressed CtBP1 levels and inhibited cell proliferation, colony formation, cell migration and sphere formation. Further analysis indicated that DNA hypermethylation in the promoter region of miR-485-3p caused the downregulation of miR-485-3p. Treatment with the DNA methylation inhibitor 5-aza-2'-deoxycytidine (AZA) resulted in the upregulation of miR-485-3p and the downregulation of CtBP1 as well as inhibited osteosarcoma cell growth. This study provides evidence that CtBP1 is also overexpressed in osteosarcoma cells and demonstrates the underlying mechanism regarding its overexpression. Thus, therapeutically targeting CtBP1 may represent an effective strategy for osteosarcoma therapy.
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Affiliation(s)
- Kaili Du
- Department of Orthopedics, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, China
| | - Xinliang Zhang
- Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710054, China
| | - Zhenkai Lou
- Department of Orthopedics, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, China
| | - Peiyu Guo
- Department of Orthopedics, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, China
| | - Fan Zhang
- Department of Orthopedics, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, China
| | - Bing Wang
- Department of Orthopedics, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, China
| | - Lingqiang Chen
- Department of Orthopedics, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, China
| | - Chunqiang Zhang
- Department of Orthopedics, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, China
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24
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Blevins MA, Zhang C, Zhang L, Li H, Li X, Norris DA, Huang M, Zhao R. CPP-E1A fusion peptides inhibit CtBP-mediated transcriptional repression. Mol Oncol 2018; 12:1358-1373. [PMID: 29879296 PMCID: PMC6068344 DOI: 10.1002/1878-0261.12330] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 05/17/2018] [Accepted: 05/18/2018] [Indexed: 12/29/2022] Open
Abstract
The carboxyl‐terminal binding proteins (CtBP) are transcriptional corepressors that regulate the expression of multiple epithelial‐specific and pro‐apoptotic genes. Overexpression of CtBP occurs in many human cancers where they promote the epithelial‐to‐mesenchymal transition, stem cell‐like features, and cell survival, while knockdown of CtBP in tumor cells results in p53‐independent apoptosis. CtBPs are recruited to their target genes by binding to a conserved PXDLS peptide motif present in multiple DNA‐binding transcription factors. Disrupting the interaction between CtBP and its transcription factor partners may be a means of altering CtBP‐mediated transcriptional repression and a potential approach for cancer therapies. However, small molecules targeting protein–protein interactions have traditionally been difficult to identify. In this study, we took advantage of the fact that CtBP binds to a conserved peptide motif to explore the feasibility of using peptides containing the PXDLS motif fused to cell‐penetrating peptides (CPP) to inhibit CtBP function. We demonstrate that these peptides disrupt the ability of CtBP to interact with its protein partner, E1A, in an AlphaScreen assay. Moreover, these peptides can enter both lung carcinoma and melanoma cells, disrupt the interaction between CtBP and a transcription factor partner, and inhibit CtBP‐mediated transcriptional repression. Finally, the constitutive expression of one such peptide, Pep1‐E1A‐WT, in a melanoma cell line reverses CtBP‐mediated oncogenic phenotypes including proliferation, migration, and sphere formation and limits tumor growth in vivo. Together, our results suggest that CPP‐fused PXDLS‐containing peptides can potentially be developed into a research tool or therapeutic agent targeting CtBP‐mediated transcriptional events in various biological pathways.
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Affiliation(s)
- Melanie A Blevins
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA
| | - Caiguo Zhang
- Department of Dermatology, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA
| | - Lingdi Zhang
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA
| | - Hong Li
- Department of Dermatology, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA
| | - Xueni Li
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA
| | - David A Norris
- Department of Dermatology, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA
| | - Mingxia Huang
- Department of Dermatology, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA
| | - Rui Zhao
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA
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25
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Bellesis AG, Jecrois AM, Hayes JA, Schiffer CA, Royer WE. Assembly of human C-terminal binding protein (CtBP) into tetramers. J Biol Chem 2018; 293:9101-9112. [PMID: 29700119 DOI: 10.1074/jbc.ra118.002514] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Revised: 04/24/2018] [Indexed: 11/06/2022] Open
Abstract
C-terminal binding protein 1 (CtBP1) and CtBP2 are transcriptional coregulators that repress numerous cellular processes, such as apoptosis, by binding transcription factors and recruiting chromatin-remodeling enzymes to gene promoters. The NAD(H)-linked oligomerization of human CtBP is coupled to its co-transcriptional activity, which is implicated in cancer progression. However, the biologically relevant level of CtBP assembly has not been firmly established; nor has the stereochemical arrangement of the subunits above that of a dimer. Here, multi-angle light scattering (MALS) data established the NAD+- and NADH-dependent assembly of CtBP1 and CtBP2 into tetramers. An examination of subunit interactions within CtBP1 and CtBP2 crystal lattices revealed that both share a very similar tetrameric arrangement resulting from assembly of two dimeric pairs, with specific interactions probably being sensitive to NAD(H) binding. Creating a series of mutants of both CtBP1 and CtBP2, we tested the hypothesis that the crystallographically observed interdimer pairing stabilizes the solution tetramer. MALS data confirmed that these mutants disrupt both CtBP1 and CtBP2 tetramers, with the dimer generally remaining intact, providing the first stereochemical models for tetrameric assemblies of CtBP1 and CtBP2. The crystal structure of a subtle destabilizing mutant suggested that small structural perturbations of the hinge region linking the substrate- and NAD-binding domains are sufficient to weaken the CtBP1 tetramer. These results strongly suggest that the tetramer is important in CtBP function, and the series of CtBP mutants reported here can be used to investigate the physiological role of the tetramer.
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Affiliation(s)
- Andrew G Bellesis
- From the Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605 and.,the Carlson School of Chemistry and Biochemistry, Clark University, Worcester, Massachusetts 01610
| | - Anne M Jecrois
- From the Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605 and
| | - Janelle A Hayes
- From the Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605 and
| | - Celia A Schiffer
- From the Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605 and
| | - William E Royer
- From the Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605 and
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26
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Blevins MA, Huang M, Zhao R. The Role of CtBP1 in Oncogenic Processes and Its Potential as a Therapeutic Target. Mol Cancer Ther 2018; 16:981-990. [PMID: 28576945 DOI: 10.1158/1535-7163.mct-16-0592] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/11/2016] [Accepted: 02/22/2017] [Indexed: 12/24/2022]
Abstract
Transcriptional corepressor proteins have emerged as an important facet of cancer etiology. These corepressor proteins are often altered by loss- or gain-of-function mutations, leading to transcriptional imbalance. Thus, research directed at expanding our current understanding of transcriptional corepressors could impact the future development of new cancer diagnostics, prognostics, and therapies. In this review, our current understanding of the CtBP corepressors, and their role in both development and disease, is discussed in detail. Importantly, the role of CtBP1 overexpression in adult tissues in promoting the progression of multiple cancer types through their ability to modulate the transcription of developmental genes ectopically is explored. CtBP1 overexpression is known to be protumorigenic and affects the regulation of gene networks associated with "cancer hallmarks" and malignant behavior, including increased cell survival, proliferation, migration, invasion, and the epithelial-mesenchymal transition. As a transcriptional regulator of broad developmental processes capable of promoting malignant growth in adult tissues, therapeutically targeting the CtBP1 corepressor has the potential to be an effective method for the treatment of diverse tumor types. Although efforts to develop CtBP1 inhibitors are still in the early stages, the current progress and the future perspectives of therapeutically targeting this transcriptional corepressor are also discussed. Mol Cancer Ther; 16(6); 981-90. ©2017 AACR.
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Affiliation(s)
- Melanie A Blevins
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado
| | - Mingxia Huang
- Department of Dermatology, University of Colorado School of Medicine, Aurora, Colorado.
| | - Rui Zhao
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado.
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27
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Yang X, Sun Y, Li H, Shao Y, Zhao D, Yu W, Fu J. C-terminal binding protein-2 promotes cell proliferation and migration in breast cancer via suppression of p16INK4A. Oncotarget 2018; 8:26154-26168. [PMID: 28412731 PMCID: PMC5432247 DOI: 10.18632/oncotarget.15402] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 02/01/2017] [Indexed: 01/27/2023] Open
Abstract
C-terminal binding protein-2 (CtBP2) enhances cancer proliferation and metastasis. The role and mechanism of CtBP2 in breast cancer remains to be elucidated. Western blot and immunochemistry were employed to evaluate the level of CtBP2 and p16INK4A in breast cancer. Genetic manipulation was used to study the expression of p16INK4A and its downstream genes regulated by CtBP2. Functional assays, including colony formation, wound healing, transwell invasion, anchorage-independent growth assay and a xenograft tumor model were used to determine the oncogenic role of CtBP2 in breast cancer progression. The expression of CtBP2 was increased in breast cancer tissues and cell lines. The expression of p16INK4A were inversely correlated CtBP2 (r2 = 0.43, P < 0.01). The expression of both CtBP2 and p16INK4A were significantly related to histological differentiation (P < 0.01 and P = 0.004, respectively) and metastasis (P = 0.046 and 0.047, respectively). The overall survival rate was lower in patients with increased CtBP2 expression and lower p16INK4A expression. Knockdown of CtBP2 resulted in the activation of p16INK4A and down–regulation of cell cycle regulators cyclin D, cyclin E and cyclin-dependent kinase 2 and 4. This down-regulation also led to a decreased transition of the G1-S phase in breast cancer cells. Moreover, gain-of-function experiments showed that CtBP2 suppressed p16INK4A and matrix metalloproteinase-2, subsequently enhancing the migration in breast cancer. However, the silence of CtBP2 abrogated this effect. Collectively, these findings provide insight into the role CtBP2 plays in promoting proliferation and migration in breast cancer by the inhibition of p16INK4A.
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Affiliation(s)
- Xiaojing Yang
- Department of Radiation Oncology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Yi Sun
- Department of Radiation Oncology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Hongling Li
- Department of Radiation Oncology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Yuhui Shao
- Department of Radiation Oncology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Depeng Zhao
- Department of Obstetrics, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai 200040, P.R. China
| | - Weiwei Yu
- Department of Radiation Oncology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Jie Fu
- Department of Radiation Oncology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
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28
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Huang Z, Sun S, Yang C, Zheng J, Nan Y, Zhao R, Lang Z, Li H, Ma L. TIAM1 inhibits lung fibroblast differentiation in pulmonary fibrosis. Exp Ther Med 2017; 14:4254-4262. [PMID: 29067109 PMCID: PMC5647702 DOI: 10.3892/etm.2017.5024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 06/16/2017] [Indexed: 11/16/2022] Open
Abstract
The differentiation of fibroblasts to myofibroblasts is critical for the development of idiopathic pulmonary fibrosis (IPF). T-cell lymphoma invasion and metastasis 1 (TIAM1) is known to be associated with amyotrophic lateral sclerosis 1 and colorectal cancer; however, its role in IPF is unclear. The aim of the present study was to investigate the expression and roles of TIAM1 in lung fibroblasts during pulmonary fibrosis. It was demonstrated that TIAM1 expression was significantly increased in fibrotic lung tissue and lung fibroblasts from bleomycin (BLM)-treated mice compared with control mice (P<0.05). TIAM1 expression and differentiation were significantly upregulated in human lung fibroblasts challenged with transforming growth factor-β (TGF-β) compared with unchallenged cells (P<0.05). Furthermore, inhibition of the nuclear factor (NF)-κB signaling pathway significantly attenuated TGF-β-induced TIAM1 expression and decreased fibroblast differentiation in human lung fibroblasts (P<0.05). Similarly, overexpression of TIAM1 significantly inhibited TGF-β-induced fibroblast differentiation, as indicated by decreased expression of fibronectin and α-smooth muscle actin (SMA; P<0.05). The results of the present study also demonstrated that TIAM1 knockdown increased TGF-β-induced fibroblast differentiation (P<0.05). These findings suggest that TIAM1 expression is associated with lung fibroblast differentiation in pulmonary fibrosis via an NF-κB-dependent pathway, and that TIAM1 inhibits lung fibroblast differentiation in pulmonary fibrosis.
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Affiliation(s)
- Zhicheng Huang
- Department of Radiology, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
| | - Shuangyan Sun
- Department of Radiology, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
| | - Changliang Yang
- Department of Thoracic Oncology, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
| | - Jun Zheng
- Department of Radiology, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
| | - Yingji Nan
- Department of Radiology, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
| | - Ruikun Zhao
- Department of Radiology, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
| | - Zhiguo Lang
- Department of Radiology, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
| | - Hang Li
- The First Division of Chest Medicine, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
| | - Lixia Ma
- Department of Thoracic Oncology, Jilin Province Cancer Hospital, Changchun, Jilin 130012, P.R. China
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29
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Monteleone NJ, Lutz CS. miR-708-5p: a microRNA with emerging roles in cancer. Oncotarget 2017; 8:71292-71316. [PMID: 29050362 PMCID: PMC5642637 DOI: 10.18632/oncotarget.19772] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 07/16/2017] [Indexed: 02/07/2023] Open
Abstract
MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate gene expression post-transcriptionally. They are crucial for normal development and maintaining homeostasis. Researchers have discovered that dysregulated miRNA expression contributes to many pathological conditions, including cancer. miRNAs can augment or suppress tumorigenesis based on their expression and transcribed targetome in various cell types. In recent years, researchers have begun to identify miRNAs commonly dysregulated in cancer. One recently identified miRNA, miR-708-5p, has been shown to have profound roles in promoting or suppressing oncogenesis in a myriad of solid and hematological tumors. This review highlights the diverse, sometimes controversial findings reported for miR-708-5p in cancer, and the importance of further exploring this exciting miRNA.
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Affiliation(s)
- Nicholas J Monteleone
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, and the School of Graduate Studies, Health Sciences Campus - Newark, Newark, NJ 07103, USA
| | - Carol S Lutz
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, and the School of Graduate Studies, Health Sciences Campus - Newark, Newark, NJ 07103, USA
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30
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Dcona MM, Morris BL, Ellis KC, Grossman SR. CtBP- an emerging oncogene and novel small molecule drug target: Advances in the understanding of its oncogenic action and identification of therapeutic inhibitors. Cancer Biol Ther 2017; 18:379-391. [PMID: 28532298 PMCID: PMC5536941 DOI: 10.1080/15384047.2017.1323586] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
C-terminal Binding Proteins (CtBP) 1 and 2 are oncogenic transcriptional co-regulators overexpressed in many cancer types, with their expression level correlating to worse prognostic outcomes and aggressive tumor features. CtBP negatively regulates the expression of many tumor suppressor genes, while coactivating genes that promote proliferation, epithelial-mesenchymal transition, and cancer stem cell self-renewal activity. In light of this evidence, the development of novel inhibitors that mitigate CtBP function may provide clinically actionable therapeutic tools. This review article focuses on the progress made in understanding CtBP structure, role in tumor progression, and discovery and development of CtBP inhibitors that target CtBP's dehydrogenase activity and other functions, with a focus on the theory and rationale behind the designs of current inhibitors. We provide insight into the future development and use of rational combination therapy that may further augment the efficacy of CtBP inhibitors, specifically addressing metastasis and cancer stem cell populations within tumors.
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Affiliation(s)
- M Michael Dcona
- a Department of Internal Medicine , Virginia Commonwealth University , Richmond , VA , USA
| | - Benjamin L Morris
- b Department of Human and Molecular Genetics , Virginia Commonwealth University , Richmond , VA , USA
| | - Keith C Ellis
- c Department of Medicinal Chemistry , Virginia Commonwealth University , Richmond , VA , USA.,d Institute for Structural Biology , Drug Discovery and Development, Virginia Commonwealth University , Richmond , VA , USA.,e VCU Massey Cancer Center , Virginia Commonwealth University , Richmond , VA , USA
| | - Steven R Grossman
- a Department of Internal Medicine , Virginia Commonwealth University , Richmond , VA , USA.,b Department of Human and Molecular Genetics , Virginia Commonwealth University , Richmond , VA , USA.,d Institute for Structural Biology , Drug Discovery and Development, Virginia Commonwealth University , Richmond , VA , USA.,e VCU Massey Cancer Center , Virginia Commonwealth University , Richmond , VA , USA
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31
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Sumner ET, Chawla AT, Cororaton AD, Koblinski JE, Kovi RC, Love IM, Szomju BB, Korwar S, Ellis KC, Grossman SR. Transforming activity and therapeutic targeting of C-terminal-binding protein 2 in Apc-mutated neoplasia. Oncogene 2017; 36:4810-4816. [PMID: 28414304 PMCID: PMC5561459 DOI: 10.1038/onc.2017.106] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 02/23/2017] [Accepted: 03/12/2017] [Indexed: 12/28/2022]
Abstract
Overexpression of the transcriptional coregulators C-terminal binding proteins 1 and 2 (CtBP) occurs in many human solid tumors and is associated with poor prognosis. CtBP modulates oncogenic gene expression programs and is an emerging drug target, but its oncogenic role is unclear. Consistent with oncogenic potential, exogenous CtBP2 transformed primary mouse and human cells to anchorage independence similarly to mutant H-Ras. To investigate CtBP’s contribution to in vivo tumorigenesis, Apcmin/+ mice, which succumb to massive intestinal polyposis, were bred to Ctbp2+/− mice. CtBP interacts with Adenomatous Polyposis Coli (APC) protein, and is stabilized in both APC-mutated human colon cancers and Apcmin/+ intestinal polyps. Ctbp2 heterozygosity increased the median survival of Apcmin/+ mice from 21 to 48 weeks, and reduced polyp formation by 90%, with Ctbp2+/− polyps exhibiting reduced levels of β-catenin and its oncogenic transcriptional target, cyclin D1. Ctbp’s potential as a therapeutic target was studied by treating Apcmin/+ mice with the CtBP small molecule inhibitors 4-methlythio-2-oxobutyric acid and 2-hydroxy-imino phenylpyruvic acid, both of which reduced polyposis by more than half compared with vehicle treatment. Phenocopying Ctbp2 deletion, both Ctbp inhibitors caused substantial decreases in the protein level of Ctbp2, as well its oncogenic partner β-catenin, and the effects of the inhibitors on CtBP and β-catenin levels could be modeled in an APC mutated human colon cancer cell line. CtBP2 is thus a druggable transforming oncoprotein critical for the evolution of neoplasia driven by Apc mutation.
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Affiliation(s)
- E T Sumner
- Department of Pharmacology/Toxicology, Virginia Commonwealth University, Richmond, VA, USA
| | - A T Chawla
- Wright Center for Clinical and Translational Research, Virginia Commonwealth University, Richmond, VA, USA
| | - A D Cororaton
- Department of Internal Medicine, Virginia Commonwealth University, Massey Cancer Center, Richmond, VA, USA
| | - J E Koblinski
- Department of Pathology, Virginia Commonwealth University, Richmond, VA, USA.,VCU Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA
| | - R C Kovi
- Cellular and Molecular Pathology Branch, NIEHS, Research Triangle Park, NC, USA
| | - I M Love
- Department of Internal Medicine, Virginia Commonwealth University, Massey Cancer Center, Richmond, VA, USA
| | - B B Szomju
- Department of Internal Medicine, Virginia Commonwealth University, Massey Cancer Center, Richmond, VA, USA
| | - S Korwar
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, USA
| | - K C Ellis
- VCU Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA.,Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, USA
| | - S R Grossman
- Department of Pharmacology/Toxicology, Virginia Commonwealth University, Richmond, VA, USA.,Department of Internal Medicine, Virginia Commonwealth University, Massey Cancer Center, Richmond, VA, USA.,VCU Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA
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32
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Dalamaga M, Christodoulatos GS. Visfatin, Obesity, and Cancer. ADIPOCYTOKINES, ENERGY BALANCE, AND CANCER 2017. [DOI: 10.1007/978-3-319-41677-9_6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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33
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Ray SK, Li HJ, Leiter AB. Oligomeric form of C-terminal-binding protein coactivates NeuroD1-mediated transcription. FEBS Lett 2016; 591:205-212. [PMID: 27880001 DOI: 10.1002/1873-3468.12501] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 11/01/2016] [Accepted: 11/07/2016] [Indexed: 12/12/2022]
Abstract
The mechanism underlying transcriptional coactivation by the corepressor C-terminal-binding protein (CtBP) is not established. We previously found that CtBP co-occupies several actively transcribed endocrine genes with the transcription factor NeuroD1 to paradoxically increase transcription by recruiting KDM1A and CoREST. While the importance of the oligomeric form of CtBP for corepression is well established, the role of oligomerization in transcriptional coactivation has received little attention. Here, we examined the importance of the oligomeric state of CtBP for coactivation of NeuroD1-dependent transcription by expressing a CtBP dimerization mutant in cells depleted of endogenous CtBP. Dimerization mutants failed to increase transcription or to associate with KDM1A and CoREST, suggesting that oligomeric, but not monomeric CtBP is required to recruit other proteins needed to activate transcription.
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Affiliation(s)
- Subir K Ray
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Hui J Li
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Andrew B Leiter
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
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34
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C-Terminal Binding Protein is Involved in Promoting to the Carcinogenesis of Human Glioma. Mol Neurobiol 2016; 54:6121-6132. [PMID: 27699603 DOI: 10.1007/s12035-016-0159-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 09/22/2016] [Indexed: 12/13/2022]
Abstract
C-terminal binding protein (CtBP) is responsible for regulating the pathogenesis of a lot of cancer types. However, whether CtBP1/2 is involved in regulating the growth and development of human glioma is still obscure. In the present study presented here, our results firstly reveal that CtBP1/2 deficiency, induced by siRNA interference, disrupts the functional integrity of the MRN complex that is responsible for DNA repair in human glioma cells. The dysfunction of the MRN complex further contributes to the up-regulation of ATM and Rad3-related kinase (ATR) and Chk1 signaling pathway, which inhibits cell cycle progression mediated by CDK2, preparing for the initiation of DNA repair. Under the condition of hypoxia, hypoxia-inducible factor-1α (HIF-1α) can be directly regulated by CDK2 on protein level, playing coordinately regulatory role in the carcinogenesis of human glioma cells. Overall, our findings reveal that CtBP1/2 is essential to promote to human glioma cell growth through maintaining the DNA stability regulated by the MRN/ATR/Chk1/CDK2/HIF-1α signaling pathway.
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35
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Zhao Z, Wang L, Di L. Compartmentation of metabolites in regulating epigenome of cancer. Mol Med 2016; 22:349-360. [PMID: 27258652 DOI: 10.2119/molmed.2016.00051] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 04/14/2016] [Indexed: 01/10/2023] Open
Abstract
Covalent modification of DNA and histones are important epigenetic events and the genome wide reshaping of epigenetic markers is common in cancer. The epigenetic markers are produced by enzymatic reactions and some of these reactions require the presence of metabolites as cofactors (termed Epigenetic Enzyme Required Metabolites, EERMs). Recent studies found that the abundance of these EERMs correlates with epigenetic enzyme activities. Also, the subcellular compartmentation, especially the nuclear localization of these EERMs may play a role in regulating the activities of epigenetic enzymes. Moreover, gene specific recruitment of enzymes which produce the EERMs in the proximity of the epigenetic modification events accompanying the gene expression regulation, were proposed. Therefore, it is of importance to summarize these findings of the EERMs in regulating the epigenetic modifications at both DNA and histone levels, and to understand how EERMs contribute to cancer development by addressing their global versus local distribution.
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Affiliation(s)
- Zhiqiang Zhao
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Li Wang
- Faculty of Health Sciences, University of Macau, Macau SAR, China.,Metabolomics Core, Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Lijun Di
- Faculty of Health Sciences, University of Macau, Macau SAR, China
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36
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Patel J, Baranwal S, Love IM, Patel NJ, Grossman SR, Patel BB. Inhibition of C-terminal binding protein attenuates transcription factor 4 signaling to selectively target colon cancer stem cells. Cell Cycle 2015; 13:3506-18. [PMID: 25483087 DOI: 10.4161/15384101.2014.958407] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Selective targeting of cancer stem cells (CSCs), implicated in tumor relapse, holds great promise in the treatment of colorectal cancer. Overexpression of C-terminal binding protein (CtBP), an NADH dependent transcriptional regulator, is often observed in colon cancer. Of note, TCF-4 signaling is also up-regulated in colonic CSCs. We hypothesized that CtBP, whose dehydrogenase activity is amenable to pharmacological inhibition by 4-methylthio-2-oxobutyric acid (MTOB), positively regulates TCF-4 signaling, leading to CSC growth and self-renewal. CSCs demonstrated significant upregulation of CtBP1 and CtBP2 levels (mRNA and protein) and activity partly due to increased NADH/NAD ratio, as well as increased TCF/LEF transcriptional activity, compared to respective controls. Depletion of CtBP2 inhibited, while its overexpression enhanced, CSC growth (1° spheroids) and self-renewal (2°/3° spheroids). Similarly, MTOB caused a robust inhibition of spheroid growth and self-renewal in a dose dependent manner. MTOB displayed significantly greater selectivity for growth inhibition in the spheroids, at least in part through induction of apoptosis, compared to monolayer controls. Moreover, MTOB inhibited basal as well as induced (by GSK-3β inhibitor) TCF/LEF activity while suppressing mRNA and protein levels of several β-catenin target genes (CD44, Snail, C-MYC and LGR5). Lastly, CtBP physically interacted with TCF-4, and this interaction was significantly inhibited in the presence of MTOB. The above findings point to a novel role of CtBPs in the promotion of CSC growth and self-renewal through direct regulation of TCF/LEF transcription. Moreover, small molecular inhibition of its function can selectively target CSCs, presenting a novel approach for treatment of colorectal cancer focused on targeting of CSCs.
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Affiliation(s)
- Jagrut Patel
- a Hunter Holmes McGuire VA Medical Center ; Richmond , VA USA
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37
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Wang L, Di LJ. Wnt/β-Catenin Mediates AICAR Effect to Increase GATA3 Expression and Inhibit Adipogenesis. J Biol Chem 2015; 290:19458-68. [PMID: 26109067 DOI: 10.1074/jbc.m115.641332] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Indexed: 11/06/2022] Open
Abstract
A better understanding of the mechanism and manipulation of the tightly regulated cellular differentiation process of adipogenesis may contribute to a reduction in obesity and diabetes. Multiple transcription factors and signaling pathways are involved in the regulation of adipogenesis. Here, we report that the AMP-activated protein kinase activator, 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) can activate AMPK in preadipocytes and thus increase the expression of GATA3, an anti-adipogenic factor. However, AICAR-increased GATA3 is mediated by the stimulation of Wnt/β-catenin signaling in preadipocytes. Mechanistically, AICAR-activated AMPK inhibits GSK3β through a phosphorylation process that stabilizes β-catenin. This stabilized β-catenin then translocates into nucleus where it interacts with T-cell factors (TCF), leading to the increased β-catenin/TCF transcriptional activity that induces GATA3 expression. In addition, AICAR also relieves the repressing effect of the C-terminal-binding protein (CtBP) co-repressor by diverting CtBP away from the β-catenin·TCF complex at the GATA3 promoter. The anti-adipogenic effect of GATA3 and AICAR is consistently attenuated by the disruption of Wnt/β-catenin signaling. Furthermore, GATA3 suppresses key adipogenic regulators by binding to the promoters of these regulators, such as the peroxisome proliferator-activated receptor-γ (PPARγ) gene, and the disruption of Wnt/β-catenin signaling reduces the GATA3 binding at the PPARγ promoter. In differentiated adipocytes, GATA3 expression inhibition is facilitated by the down-regulation of β-catenin levels, the reduction in β-catenin binding, and the increase in CtBP binding at the GATA3 promoter. Our findings shed light on the molecular mechanism of adipogenesis by suggesting that different regulation pathways and adipogenic regulators collectively modulate adipocyte differentiation through cross-talk.
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Affiliation(s)
- Li Wang
- From the Metabolomics Core, Faculty of Health Sciences, University of Macau, Macau SAR (Special Administrative Region), China and
| | - Li-jun Di
- the Faculty of Health Sciences, University of Macau, Macau SAR, China
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38
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Hilbert BJ, Morris BL, Ellis KC, Paulsen JL, Schiffer CA, Grossman SR, Royer WE. Structure-guided design of a high affinity inhibitor to human CtBP. ACS Chem Biol 2015; 10:1118-27. [PMID: 25636004 DOI: 10.1021/cb500820b] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Oncogenic transcriptional coregulators C-terminal Binding Protein (CtBP) 1 and 2 possess regulatory d-isomer specific 2-hydroxyacid dehydrogenase (D2-HDH) domains that provide an attractive target for small molecule intervention. Findings that the CtBP substrate 4-methylthio 2-oxobutyric acid (MTOB) can interfere with CtBP oncogenic activity in cell culture and in mice confirm that such inhibitors could have therapeutic benefit. Recent crystal structures of CtBP 1 and 2 revealed that MTOB binds in an active site containing a dominant tryptophan and a hydrophilic cavity, neither of which are present in other D2-HDH family members. Here, we demonstrate the effectiveness of exploiting these active site features for the design of high affinity inhibitors. Crystal structures of two such compounds, phenylpyruvate (PPy) and 2-hydroxyimino-3-phenylpropanoic acid (HIPP), show binding with favorable ring stacking against the CtBP active site tryptophan and alternate modes of stabilizing the carboxylic acid moiety. Moreover, ITC experiments show that HIPP binds to CtBP with an affinity greater than 1000-fold over that of MTOB, and enzymatic assays confirm that HIPP substantially inhibits CtBP catalysis. These results, thus, provide an important step, and additional insights, for the development of highly selective antineoplastic CtBP inhibitors.
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Affiliation(s)
- Brendan J. Hilbert
- Department
of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, United States
| | - Benjamin L. Morris
- Division
of Hematology, Oncology, and Palliative Care, Department of Human
and Molecular Genetics, and Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Keith C. Ellis
- Department
of Medicinal Chemistry, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Janet L. Paulsen
- Department
of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, United States
| | - Celia A. Schiffer
- Department
of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, United States
| | - Steven R. Grossman
- Division
of Hematology, Oncology, and Palliative Care, Department of Human
and Molecular Genetics, and Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - William E. Royer
- Department
of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, United States
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39
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Interaction with CCNH/CDK7 facilitates CtBP2 promoting esophageal squamous cell carcinoma (ESCC) metastasis via upregulating epithelial-mesenchymal transition (EMT) progression. Tumour Biol 2015; 36:6701-14. [PMID: 25820824 DOI: 10.1007/s13277-015-3354-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 03/16/2015] [Indexed: 12/28/2022] Open
Abstract
CtBP2, as a transcriptional corepressor of epithelial-specific genes, has been reported to promote tumor due to upregulating epithelial-mesenchymal transition (EMT) in cancer cells. CtBP2 was also demonstrated to contribute to the proliferation of esophageal squamous cell carcinoma (ESCC) cells through a negative transcriptional regulation of p16(INK4A). In this study, for the first time, we reported that CtBP2 expression, along with CCNH/CDK7, was higher in ESCC tissues with lymph node metastases than in those without lymph node metastases. Moreover, both CtBP2 and CCNH/CDK7 were positively correlated with E-cadherin, tumor grade, and tumor metastasis. However, the concrete mechanism of CtBP2's role in enhancing ESCC migration remains incompletely understood. We confirmed that CCNH/CDK7 could directly interact with CtBP2 in ESCC cells in vivo and in vitro. Furthermore, our data demonstrate for the first time that CtBP2 enhanced the migration of ESCC cells in a CCNH/CDK7-dependent manner. Our results indicated that CCNH/CDK7-CtBP2 axis may augment ESCC cell migration, and targeting the interaction of both may provide a novel therapeutic target of ESCC.
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40
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Boxer LD, Barajas B, Tao S, Zhang J, Khavari PA. ZNF750 interacts with KLF4 and RCOR1, KDM1A, and CTBP1/2 chromatin regulators to repress epidermal progenitor genes and induce differentiation genes. Genes Dev 2014; 28:2013-26. [PMID: 25228645 PMCID: PMC4173152 DOI: 10.1101/gad.246579.114] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
ZNF750 controls epithelial homeostasis by inhibiting progenitor genes while inducing differentiation genes. Here, Boxer et al. characterized ZNF750 as a transcription factor that binds both the progenitor and differentiation genes that it controls at a CCNNAGGC DNA motif. ZNF750 controls differentiation in concert with RCOR1 and CTBP1/2 by acting with either KDM1A to repress progenitor genes or KLF4 to induce differentiation genes. ZNF750 controls epithelial homeostasis by inhibiting progenitor genes while inducing differentiation genes, a role underscored by pathogenic ZNF750 mutations in cancer and psoriasis. How ZNF750 accomplishes these dual gene regulatory impacts is unknown. Here, we characterized ZNF750 as a transcription factor that binds both the progenitor and differentiation genes that it controls at a CCNNAGGC DNA motif. ZNF750 interacts with the pluripotency transcription factor KLF4 and chromatin regulators RCOR1, KDM1A, and CTBP1/2 through conserved PLNLS sequences. ChIP-seq (chromatin immunoprecipitation [ChIP] followed by high-throughput sequencing) and gene depletion revealed that KLF4 colocalizes ∼10 base pairs from ZNF750 at differentiation target genes to facilitate their activation but is unnecessary for ZNF750-mediated progenitor gene repression. In contrast, KDM1A colocalizes with ZNF750 at progenitor genes and facilitates their repression but is unnecessary for ZNF750-driven differentiation. ZNF750 thus controls differentiation in concert with RCOR1 and CTBP1/2 by acting with either KDM1A to repress progenitor genes or KLF4 to induce differentiation genes.
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Affiliation(s)
- Lisa D Boxer
- Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California 94305, USA; Department of Biology, Stanford University, Stanford, California 94305, USA
| | - Brook Barajas
- Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Shiying Tao
- Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Jiajing Zhang
- Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Paul A Khavari
- Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California 94305, USA; Veterans Affairs Palo Alto Healthcare System, Palo Alto, California 94304, USA
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41
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Shackelford RE, Mayhall K, Maxwell NM, Kandil E, Coppola D. Nicotinamide phosphoribosyltransferase in malignancy: a review. Genes Cancer 2014; 4:447-56. [PMID: 24386506 DOI: 10.1177/1947601913507576] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 08/26/2013] [Indexed: 12/15/2022] Open
Abstract
Nicotinamide phosphoribosyltransferase (Nampt) catalyzes the rate-limiting step of nicotinamide adenine dinucleotide (NAD) synthesis. Both intracellular and extracellular Nampt (iNampt and eNampt) levels are increased in several human malignancies and some studies demonstrate increased iNampt in more aggressive/invasive tumors and in tumor metastases. Several different molecular targets have been identified that promote carcinogenesis following iNampt overexpression, including SirT1, CtBP, and PARP-1. Additionally, eNampt is elevated in several human cancers and is often associated with a higher tumor stage and worse prognoses. Here we review the roles of Nampt in malignancy, some of the known mechanisms by which it promotes carcinogenesis, and discuss the possibility of employing Nampt inhibitors in cancer treatment.
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Affiliation(s)
| | - Kim Mayhall
- Tulane University School of Medicine, New Orleans, LA, USA
| | | | - Emad Kandil
- Tulane University School of Medicine, New Orleans, LA, USA
| | - Domenico Coppola
- Anatomic Pathology Department, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
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42
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Schmitz F. Presynaptic [Ca(2+)] and GCAPs: aspects on the structure and function of photoreceptor ribbon synapses. Front Mol Neurosci 2014; 7:3. [PMID: 24567702 PMCID: PMC3915146 DOI: 10.3389/fnmol.2014.00003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 01/15/2014] [Indexed: 12/21/2022] Open
Abstract
Changes in intracellular calcium ions [Ca2+] play important roles in photoreceptor signaling. Consequently, intracellular [Ca2+] levels need to be tightly controlled. In the light-sensitive outer segments (OS) of photoreceptors, Ca2+ regulates the activity of retinal guanylate cyclases thus playing a central role in phototransduction and light-adaptation by restoring light-induced decreases in cGMP. In the synaptic terminals, changes of intracellular Ca2+ trigger various aspects of neurotransmission. Photoreceptors employ tonically active ribbon synapses that encode light-induced, graded changes of membrane potential into modulation of continuous synaptic vesicle exocytosis. The active zones of ribbon synapses contain large electron-dense structures, synaptic ribbons, that are associated with large numbers of synaptic vesicles. Synaptic coding at ribbon synapses differs from synaptic coding at conventional (phasic) synapses. Recent studies revealed new insights how synaptic ribbons are involved in this process. This review focuses on the regulation of [Ca2+] in presynaptic photoreceptor terminals and on the function of a particular Ca2+-regulated protein, the neuronal calcium sensor protein GCAP2 (guanylate cyclase-activating protein-2) in the photoreceptor ribbon synapse. GCAP2, an EF-hand-containing protein plays multiple roles in the OS and in the photoreceptor synapse. In the OS, GCAP2 works as a Ca2+-sensor within a Ca2+-regulated feedback loop that adjusts cGMP levels. In the photoreceptor synapse, GCAP2 binds to RIBEYE, a component of synaptic ribbons, and mediates Ca2+-dependent plasticity at that site. Possible mechanisms are discussed.
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Affiliation(s)
- Frank Schmitz
- Department of Neuroanatomy, Institute for Anatomy and Cell Biology, Medical School Homburg/Saar, Saarland University Saarland, Germany
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43
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McClellan MJ, Wood CD, Ojeniyi O, Cooper TJ, Kanhere A, Arvey A, Webb HM, Palermo RD, Harth-Hertle ML, Kempkes B, Jenner RG, West MJ. Modulation of enhancer looping and differential gene targeting by Epstein-Barr virus transcription factors directs cellular reprogramming. PLoS Pathog 2013; 9:e1003636. [PMID: 24068937 PMCID: PMC3771879 DOI: 10.1371/journal.ppat.1003636] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Accepted: 08/03/2013] [Indexed: 12/28/2022] Open
Abstract
Epstein-Barr virus (EBV) epigenetically reprogrammes B-lymphocytes to drive immortalization and facilitate viral persistence. Host-cell transcription is perturbed principally through the actions of EBV EBNA 2, 3A, 3B and 3C, with cellular genes deregulated by specific combinations of these EBNAs through unknown mechanisms. Comparing human genome binding by these viral transcription factors, we discovered that 25% of binding sites were shared by EBNA 2 and the EBNA 3s and were located predominantly in enhancers. Moreover, 80% of potential EBNA 3A, 3B or 3C target genes were also targeted by EBNA 2, implicating extensive interplay between EBNA 2 and 3 proteins in cellular reprogramming. Investigating shared enhancer sites neighbouring two new targets (WEE1 and CTBP2) we discovered that EBNA 3 proteins repress transcription by modulating enhancer-promoter loop formation to establish repressive chromatin hubs or prevent assembly of active hubs. Re-ChIP analysis revealed that EBNA 2 and 3 proteins do not bind simultaneously at shared sites but compete for binding thereby modulating enhancer-promoter interactions. At an EBNA 3-only intergenic enhancer site between ADAM28 and ADAMDEC1 EBNA 3C was also able to independently direct epigenetic repression of both genes through enhancer-promoter looping. Significantly, studying shared or unique EBNA 3 binding sites at WEE1, CTBP2, ITGAL (LFA-1 alpha chain), BCL2L11 (Bim) and the ADAMs, we also discovered that different sets of EBNA 3 proteins bind regulatory elements in a gene and cell-type specific manner. Binding profiles correlated with the effects of individual EBNA 3 proteins on the expression of these genes, providing a molecular basis for the targeting of different sets of cellular genes by the EBNA 3s. Our results therefore highlight the influence of the genomic and cellular context in determining the specificity of gene deregulation by EBV and provide a paradigm for host-cell reprogramming through modulation of enhancer-promoter interactions by viral transcription factors. Epstein-Barr virus (EBV) is associated with numerous cancers. The ability of the virus to infect B-cells and convert them from short-lived into immortal cells is the key to its cancer-promoting properties. A small number of EBV transcription factors are required for immortalization and act in concert to drive cell growth by deregulating the expression of cellular genes through largely unknown mechanisms. We have demonstrated that four of these key transcription factors function cooperatively by targeting common genes via long-range enhancer elements and modulating their looping interactions with gene promoters. Specifically we show that gene repression by the EBV EBNA 3 family of proteins can be mediated through the modulation of enhancer-promoter looping. Our results also reveal that different subsets of EBNA 3 proteins are bound at different genes and that this differential binding can vary in lymphoma cells compared to cells immortalized in culture, indicating that cell-background-specific gene regulation may be important in lymphoma development. Our results demonstrate how cellular genes can be deregulated by an oncogenic virus through modulation of enhancer-promoter looping with the specificity of binding by viral transcription factors controlling cellular reprogramming in a gene and cell-type specific manner.
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Affiliation(s)
- Michael J. McClellan
- School of Life Sciences, John Maynard-Smith Building, University of Sussex, Falmer, Brighton, United Kingdom
| | - C. David Wood
- School of Life Sciences, John Maynard-Smith Building, University of Sussex, Falmer, Brighton, United Kingdom
| | - Opeoluwa Ojeniyi
- School of Life Sciences, John Maynard-Smith Building, University of Sussex, Falmer, Brighton, United Kingdom
| | - Tim J. Cooper
- School of Life Sciences, John Maynard-Smith Building, University of Sussex, Falmer, Brighton, United Kingdom
| | - Aditi Kanhere
- MRC Centre for Medical Molecular Virology, Division of Infection and Immunity, Paul O'Gorman Building, University College London, London, United Kingdom
| | - Aaron Arvey
- Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Helen M. Webb
- School of Life Sciences, John Maynard-Smith Building, University of Sussex, Falmer, Brighton, United Kingdom
| | - Richard D. Palermo
- School of Life Sciences, John Maynard-Smith Building, University of Sussex, Falmer, Brighton, United Kingdom
| | - Marie L. Harth-Hertle
- Department of Gene Vectors, Helmholtz Center Munich, German Research Center for Environmental Health, Munich, Germany
| | - Bettina Kempkes
- Department of Gene Vectors, Helmholtz Center Munich, German Research Center for Environmental Health, Munich, Germany
| | - Richard G. Jenner
- MRC Centre for Medical Molecular Virology, Division of Infection and Immunity, Paul O'Gorman Building, University College London, London, United Kingdom
| | - Michelle J. West
- School of Life Sciences, John Maynard-Smith Building, University of Sussex, Falmer, Brighton, United Kingdom
- * E-mail:
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