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Ravichandran G, Pasupuleti M, Arasu MV, Al-Dhabi NA, Arshad A, Arockiaraj J. Innate immune function of serine/threonine-protein kinase from Macrobrachium rosenbergii in response to host-pathogen interactions. FISH & SHELLFISH IMMUNOLOGY 2020; 106:332-340. [PMID: 32758637 DOI: 10.1016/j.fsi.2020.07.068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 07/10/2020] [Accepted: 07/31/2020] [Indexed: 06/11/2023]
Abstract
The occurrences of multiple drug-resistant strains have been relentlessly increasing in recent years. The aquaculture industry has encountered major disease outbreaks and crucially affected by this situation. The usage of non-specific chemicals and antibiotics expedites the stimulation of resistant strains. Triggering the natural defense mechanism would provide an effective and safest way of protecting the host system. Hence, we have investigated the innate immune function of serine/threonine-protein kinase (STPK) in Macrobrachium rosenbergii (Mr). The in-silico protein analysis resulted in the identification of cationic antimicrobial peptide, MrSL-19, with interesting properties from STPK of M. rosenbergii. Antimicrobial assay, FACS and SEM analysis demonstrated that the peptide potentially inhibits Staphylococcus aureus by interacting with its membrane. The toxic study on MrSL-19 demonstrated that the peptide is not toxic against HEK293 cells as well as human erythrocytes. This investigation showed the significant innate immune property of an efficient cationic antimicrobial peptide, MrSL-19 of STPK from M. rosenbergii.
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Affiliation(s)
- Gayathri Ravichandran
- SRM Research Institute, SRM Institute of Science and Technology, Kattankulathur, 603 203, Chennai, Tamil Nadu, India
| | - Mukesh Pasupuleti
- Lab PCN 206, Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, 226 031, Uttar Pradesh, India
| | - Mariadhas Valan Arasu
- Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia
| | - Naif Abdullah Al-Dhabi
- Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia
| | - Aziz Arshad
- International Institute of Aquaculture and Aquatic Sciences (I-AQUAS), Universiti Putra Malaysia, 71050, Port Dickson, Negeri Sembilan, Malaysia; Department of Aquaculture, Faculty of Agriculture, Universiti Putra Malaysia, Serdang, 43400, Selangor, Malaysia
| | - Jesu Arockiaraj
- SRM Research Institute, SRM Institute of Science and Technology, Kattankulathur, 603 203, Chennai, Tamil Nadu, India.
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Szoltysek K, Ciardullo C, Zhou P, Walaszczyk A, Willmore E, Rand V, Marshall S, Hall A, J. Harrison C, Eswaran J, Soundararajan M. DAP Kinase-Related Apoptosis-Inducing Protein Kinase 2 (DRAK2) Is a Key Regulator and Molecular Marker in Chronic Lymphocytic Leukemia. Int J Mol Sci 2020; 21:ijms21207663. [PMID: 33081245 PMCID: PMC7593912 DOI: 10.3390/ijms21207663] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/13/2020] [Accepted: 10/14/2020] [Indexed: 02/07/2023] Open
Abstract
Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in the Western World and it is characterized by a marked degree of clinical heterogeneity. An impaired balance between pro- and anti-apoptotic stimuli determines chemorefractoriness and outcome. The low proliferation rate of CLL cells indicates that one of the primary mechanisms involved in disease development may be an apoptotic failure. Here, we study the clinical and functional significance of DRAK2, a novel stress response kinase that plays a critical role in apoptosis, T-cell biology, and B-cell activation in CLL. We have analyzed CLL patient samples and showed that low expression levels of DRAK2 were significantly associated with unfavorable outcome in our CLL cohort. DRAK2 expression levels showed a positive correlation with the expression of DAPK1, and TGFBR1. Consistent with clinical data, the downregulation of DRAK2 in MEC-1 CLL cells strongly increased cell viability and proliferation. Further, our transcriptome data from MEC-1 cells highlighted MAPK, NF-κB, and Akt and as critical signaling hubs upon DRAK2 knockdown. Taken together, our results indicate DRAK2 as a novel marker of CLL survival that plays key regulatory roles in CLL prognosis.
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MESH Headings
- Aged
- Apoptosis Regulatory Proteins/genetics
- Apoptosis Regulatory Proteins/metabolism
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Cell Proliferation
- Cell Survival
- Death-Associated Protein Kinases/genetics
- Death-Associated Protein Kinases/metabolism
- Down-Regulation
- Female
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/metabolism
- Leukemia, Lymphocytic, Chronic, B-Cell/pathology
- MAP Kinase Signaling System
- Male
- Middle Aged
- NF-kappa B/genetics
- NF-kappa B/metabolism
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/metabolism
- Proto-Oncogene Proteins c-akt/genetics
- Proto-Oncogene Proteins c-akt/metabolism
- Receptor, Transforming Growth Factor-beta Type I/genetics
- Receptor, Transforming Growth Factor-beta Type I/metabolism
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Affiliation(s)
- Katarzyna Szoltysek
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; (K.S.); (C.C.); (E.W.); (A.H.); (C.J.H.)
- Maria Skłodowska-Curie Institute, Oncology Center, Gliwice Branch, 02-034 Gliwice, Poland
| | - Carmela Ciardullo
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; (K.S.); (C.C.); (E.W.); (A.H.); (C.J.H.)
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne NE1 8ST, UK
| | - Peixun Zhou
- School of Health & Life Sciences, Teesside University, Middlesbrough TS1 3JN, UK; (P.Z.); (V.R.)
- National Horizons Centre, Teesside University, Darlington DL1 1HG, UK
| | - Anna Walaszczyk
- Institute of Biosciences, International Centre for Life, Newcastle University, Newcastle upon Tyne NE1 7RU, UK;
| | - Elaine Willmore
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; (K.S.); (C.C.); (E.W.); (A.H.); (C.J.H.)
| | - Vikki Rand
- School of Health & Life Sciences, Teesside University, Middlesbrough TS1 3JN, UK; (P.Z.); (V.R.)
- National Horizons Centre, Teesside University, Darlington DL1 1HG, UK
| | - Scott Marshall
- Department of Haematology, City Hospitals Sunderland NHS Trust, Sunderland SR4 7TP, UK;
| | - Andy Hall
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; (K.S.); (C.C.); (E.W.); (A.H.); (C.J.H.)
| | - Christine J. Harrison
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; (K.S.); (C.C.); (E.W.); (A.H.); (C.J.H.)
| | - Jeyanthy Eswaran
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; (K.S.); (C.C.); (E.W.); (A.H.); (C.J.H.)
- Newcastle University Medicine Malaysia (NUMed Malaysia), EduCity, Iskandar 79200, Johor, Malaysia
- Correspondence: or (J.E); (M.S.)
| | - Meera Soundararajan
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne NE1 8ST, UK
- Correspondence: or (J.E); (M.S.)
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Manivannan P, Reddy V, Mukherjee S, Clark KN, Malathi K. RNase L Induces Expression of A Novel Serine/Threonine Protein Kinase, DRAK1, to Promote Apoptosis. Int J Mol Sci 2019; 20:E3535. [PMID: 31330998 PMCID: PMC6679093 DOI: 10.3390/ijms20143535] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 07/12/2019] [Accepted: 07/17/2019] [Indexed: 11/28/2022] Open
Abstract
Apoptosis of virus-infected cells is an effective antiviral mechanism in addition to interferon induction to establish antiviral state to restrict virus spread. The interferon-inducible 2'-5' oligoadenylate synthetase/RNase L pathway results in activation of RNase L in response to double stranded RNA and cleaves diverse RNA substrates to amplify interferon induction and promote apoptosis. Here we show that RNase L induces expression of Death-associated protein kinase-Related Apoptosis-inducing protein Kinase 1 (DRAK1), a member of the death-associated protein kinase family and interferon-signaling pathway is required for induction. Overexpression of DRAK1 triggers apoptosis in the absence of RNase L activation by activating c-Jun N-terminal kinase (JNK), translocation of BCL2 Associated X (Bax) to the mitochondria accompanied by cytochrome C release and loss of mitochondrial membrane potential promoting cleavage of caspase 3 and Poly(ADP-Ribose) Polymerase 1 (PARP). Inhibitors of JNK and caspase 3 promote survival of DRAK1 overexpressing cells demonstrating an important role of JNK signaling pathway in DRAK1-mediated apoptosis. DRAK1 mutant proteins that lack kinase activity or nuclear localization fail to induce apoptosis highlighting the importance of cellular localization and kinase function in promoting cell death. Our studies identify DRAK1 as a mediator of RNase L-induced apoptosis.
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Affiliation(s)
- Praveen Manivannan
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA
| | - Vidita Reddy
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA
| | - Sushovita Mukherjee
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA
| | - Kirsten Neytania Clark
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA
| | - Krishnamurthy Malathi
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA.
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Farag AK, Roh EJ. Death-associated protein kinase (DAPK) family modulators: Current and future therapeutic outcomes. Med Res Rev 2018; 39:349-385. [DOI: 10.1002/med.21518] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 05/06/2018] [Accepted: 06/03/2018] [Indexed: 12/22/2022]
Affiliation(s)
- Ahmed Karam Farag
- Chemical Kinomics Research Center; Korea Institute of Science and Technology (KIST); Seoul Republic of Korea
- Division of Bio-Medical Science &Technology, Korea Institute of Science and Technology (KIST) School; University of Science and Technology; Seoul Republic of Korea
| | - Eun Joo Roh
- Chemical Kinomics Research Center; Korea Institute of Science and Technology (KIST); Seoul Republic of Korea
- Division of Bio-Medical Science &Technology, Korea Institute of Science and Technology (KIST) School; University of Science and Technology; Seoul Republic of Korea
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6
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Lan Y, Han J, Wang Y, Wang J, Yang G, Li K, Song R, Zheng T, Liang Y, Pan S, Liu X, Zhu M, Liu Y, Meng F, Mohsin M, Cui Y, Zhang B, Subash S, Liu L. STK17B promotes carcinogenesis and metastasis via AKT/GSK-3β/Snail signaling in hepatocellular carcinoma. Cell Death Dis 2018; 9:236. [PMID: 29445189 PMCID: PMC5833726 DOI: 10.1038/s41419-018-0262-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 11/10/2017] [Accepted: 11/24/2017] [Indexed: 12/24/2022]
Abstract
Hepatocellular carcinoma (HCC) is a lethal malignancy worldwide with frequent intrahepatic and distant metastasis. Elucidating the underlying molecular mechanism that modulates HCC progression is critical for exploring novel therapeutic strategies. Serine/Threonine Kinase 17B (STK17B) is upregulated in HCC tissues, but its role in HCC progression remains elusive. In the present studies, we reported that STK17B had a critical role in HCC progression. STK17B was significantly upregulated in HCC cell lines and specimens, and patients with ectopic STK17B expression characterized with poor clinicopathological features. In vitro and in vivo assay demonstrated that inhibition of STK17B markedly inhibits HCC tumorigenesis and metastasis, while STK17B overexpression promoted these processes. Furthermore, we found that STK17B promoted EMT process via activating AKT/GSK-3β/Snail signal pathway, and miR-455-3p was identified as the upstream regulator of STK17B. Combination of high level of STK17B and low level of miR-455-3p predicted poor prognosis with higher accuracy for HCC patients. In conclusion, our research demonstrated that STK17B promotes HCC progression, induces EMT process via activating AKT/GSK-3β/Snail signal and predicts poor prognosis in HCC.
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Affiliation(s)
- Yaliang Lan
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Jihua Han
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Yan Wang
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Jiabei Wang
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Guangchao Yang
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Keyu Li
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Ruipeng Song
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Tongsen Zheng
- Department of Gastrointestinal Medical Oncology, The Affiliated Tumor Hospital of Harbin Medical University, Harbin, China
| | - Yingjian Liang
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Shangha Pan
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Xirui Liu
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Mingxi Zhu
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Yao Liu
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Fanzheng Meng
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Manzoor Mohsin
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Yifeng Cui
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Bo Zhang
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Sharma Subash
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China
| | - Lianxin Liu
- Department of Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Harbin, China.
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7
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Discovery of indirubin derivatives as new class of DRAK2 inhibitors from high throughput screening. Bioorg Med Chem Lett 2016; 26:2719-23. [PMID: 27106709 DOI: 10.1016/j.bmcl.2016.03.111] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 03/27/2016] [Accepted: 03/31/2016] [Indexed: 01/14/2023]
Abstract
DRAK2 is a serine/threonine kinase belonging to the death-associated protein kinase (DAPK) family and has emerged as a promising drug target for the treatment of autoimmune diseases and cancers. To identify small molecule inhibitors for DRAK2, we performed a high throughput screening campaign using in-house chemical library and identified indirubin-3'-monoximes as novel class of DRAK2 inhibitors. Among the compounds tested, compound 16 exhibited the most potent inhibitory activity against DRAK2 (IC50=0.003μM). We also propose that compound 16 may bind to the ATP-binding site of the enzyme based on enzyme kinetics and molecular docking studies.
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8
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Harris TL, McGargill MA. Drak2 Does Not Regulate TGF-β Signaling in T Cells. PLoS One 2015; 10:e0123650. [PMID: 25951457 PMCID: PMC4423867 DOI: 10.1371/journal.pone.0123650] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 02/10/2015] [Indexed: 12/31/2022] Open
Abstract
Drak2 is a serine/threonine kinase expressed highest in T cells and B cells. Drak2-/- mice are resistant to autoimmunity in mouse models of type 1 diabetes and multiple sclerosis. Resistance to these diseases occurs, in part, because Drak2 is required for the survival of autoreactive T cells that induce disease. However, the molecular mechanisms by which Drak2 affects T cell survival and autoimmunity are not known. A recent report demonstrated that Drak2 negatively regulated transforming growth factor-β (TGF-β) signaling in tumor cell lines. Thus, increased TGF-β signaling in the absence of Drak2 may contribute to the resistance to autoimmunity in Drak2-/- mice. Therefore, we examined if Drak2 functioned as a negative regulator of TGF-β signaling in T cells, and whether the enhanced susceptibility to death of Drak2-/- T cells was due to augmented TGF-β signaling. Using several in vitro assays to test TGF-β signaling and T cell function, we found that activation of Smad2 and Smad3, which are downstream of the TGF-β receptor, was similar between wildtype and Drak2-/- T cells. Furthermore, TGF-β-mediated effects on naïve T cell proliferation, activated CD8+ T cell survival, and regulatory T cell induction was similar between wildtype and Drak2-/- T cells. Finally, the increased susceptibility to death in the absence of Drak2 was not due to enhanced TGF-β signaling. Together, these data suggest that Drak2 does not function as a negative regulator of TGF-β signaling in primary T cells stimulated in vitro. It is important to investigate and discern potential molecular mechanisms by which Drak2 functions in order to better understand the etiology of autoimmune diseases, as well as to validate the use of Drak2 as a target for therapeutic treatment of these diseases.
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Affiliation(s)
- Tarsha L. Harris
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
- Integrated Biomedical Sciences Program, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Maureen A. McGargill
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
- Integrated Biomedical Sciences Program, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
- * E-mail:
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9
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Edwards BA, Harris TL, Floersh H, Lukens JR, Zaki MH, Vogel P, Kanneganti TD, Bui JD, McGargill MA. Drak2 is not required for tumor surveillance and suppression. Int Immunol 2015; 27:161-6. [PMID: 25568303 DOI: 10.1093/intimm/dxu146] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Drak2 is a promising therapeutic target to treat organ-specific autoimmune diseases such as type 1 diabetes and multiple sclerosis without causing generalized immune suppression. Inhibition of Drak2 may also prevent graft rejection following organ transplantation. However, Drak2 may function as a critical tumor suppressor, which would challenge the prospect of targeting Drak2 for therapeutic treatment. Thus, we examined the susceptibility of Drak2 (-/-) mice in several tumor models. We show that Drak2 is not required to prevent tumor formation in a variety of settings. Therefore, Drak2 does not function as an essential tumor suppressor in in vivo tumor models. These data further validate Drak2 as a viable therapeutic target to treat autoimmune disease and graft rejection. Importantly, these data also indicate that while Drak2 may induce apoptosis when overexpressed in cell lines, it is not an essential tumor suppressor.
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Affiliation(s)
- Benjamin A Edwards
- Department of Immunology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, MS 351, Memphis, TN 38105, USA
| | - Tarsha L Harris
- Department of Immunology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, MS 351, Memphis, TN 38105, USA
| | - Helen Floersh
- Department of Immunology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, MS 351, Memphis, TN 38105, USA
| | - John R Lukens
- Department of Immunology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, MS 351, Memphis, TN 38105, USA
| | - Md Hasan Zaki
- Department of Immunology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, MS 351, Memphis, TN 38105, USA
| | - Peter Vogel
- Department of Veterinary Pathology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Thirumala-Devi Kanneganti
- Department of Immunology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, MS 351, Memphis, TN 38105, USA
| | - Jack D Bui
- Department of Pathology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Maureen A McGargill
- Department of Immunology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, MS 351, Memphis, TN 38105, USA
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Gallagher SJ, Mijatov B, Gunatilake D, Tiffen JC, Gowrishankar K, Jin L, Pupo GM, Cullinane C, Prinjha RK, Smithers N, McArthur GA, Rizos H, Hersey P. The epigenetic regulator I-BET151 induces BIM-dependent apoptosis and cell cycle arrest of human melanoma cells. J Invest Dermatol 2014; 134:2795-2805. [PMID: 24906137 DOI: 10.1038/jid.2014.243] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 03/14/2014] [Accepted: 04/08/2014] [Indexed: 11/09/2022]
Abstract
Epigenetic changes are widespread in melanoma and contribute to the pathogenic biology of this disease. In the present study, we show that I-BET151, which belongs to a new class of drugs that target the BET family of epigenetic "reader" proteins, inhibits melanoma growth in vivo and induced variable degrees of apoptosis in a panel of melanoma cells. Apoptosis was caspase dependent and associated with G1 cell cycle arrest. All melanoma cells tested had increased levels of the BH3 proapoptotic protein BIM, which appeared to be regulated by the BRD2 BET protein and to some extent by BRD3. In contrast, knockdown experiments indicated that inhibition of BRD4 was associated with decreased levels of BIM. Apoptosis was dependent on BIM in some but not all cell lines, indicating that other factors were determinants of apoptosis, such as downregulation of antiapoptotic proteins revealed in gene expression arrays. G1 cell cycle arrest appeared to be mediated by p21 and resulted from inhibition of the BRD4 protein. The activity of BET protein inhibitors appears independent of the BRAF and NRAS mutational status of melanoma, and further studies to assess their therapeutic role in melanoma are warranted.
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Affiliation(s)
- Stuart J Gallagher
- Melanoma Research Group, Kolling Institute of Medical Research, University of Sydney, St Leonards, New South Wales, Australia
| | - Branka Mijatov
- Melanoma Research Group, Kolling Institute of Medical Research, University of Sydney, St Leonards, New South Wales, Australia
| | - Dilini Gunatilake
- Melanoma Research Group, Kolling Institute of Medical Research, University of Sydney, St Leonards, New South Wales, Australia
| | - Jessamy C Tiffen
- Melanoma Research Group, Kolling Institute of Medical Research, University of Sydney, St Leonards, New South Wales, Australia
| | - Kavitha Gowrishankar
- Melanoma Research Group, Kolling Institute of Medical Research, University of Sydney, St Leonards, New South Wales, Australia
| | - Lei Jin
- Melanoma Research Group, Kolling Institute of Medical Research, University of Sydney, St Leonards, New South Wales, Australia
| | - Gulietta M Pupo
- Westmead Institute for Cancer Research, The University of Sydney at Westmead Millennium Institute, Westmead Hospital, Westmead, New South Wales, Australia
| | - Carleen Cullinane
- Translational Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Oncogenic Signalling and Growth Control Program, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Rab K Prinjha
- Epinova Discovery Performance Unit, GlaxoSmithKline, Stevenage, UK
| | | | - Grant A McArthur
- Translational Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Oncogenic Signalling and Growth Control Program, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Helen Rizos
- Westmead Institute for Cancer Research, The University of Sydney at Westmead Millennium Institute, Westmead Hospital, Westmead, New South Wales, Australia
| | - Peter Hersey
- Melanoma Research Group, Kolling Institute of Medical Research, University of Sydney, St Leonards, New South Wales, Australia; Melanoma Institute of Australia, North Sydney, New South Wales, Australia.
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11
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Ye P, Zhao L, Gonda TJ. The MYB oncogene can suppress apoptosis in acute myeloid leukemia cells by transcriptional repression of DRAK2 expression. Leuk Res 2013; 37:595-601. [PMID: 23398943 DOI: 10.1016/j.leukres.2013.01.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 01/14/2013] [Accepted: 01/16/2013] [Indexed: 11/19/2022]
Abstract
RNA interference-mediated suppression of MYB expression promoted apoptosis in the AML cell line U937, without affecting expression of the anti-apoptotic MYB target BCL2. This was accompanied by up-regulation of the pro-apoptotic gene DRAK2 and stimulation of caspase-9 activity. Moreover, RNA interference-mediated suppression of DRAK2 in U937 cells alleviated apoptosis induced by MYB down-regulation. Finally ChIP assays showed that in U937 cells MYB binds to a conserved element upstream of the DRAK2 transcription start site. Together, these findings identify a novel mechanism by which MYB suppresses apoptosis in an AML model cell line.
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Affiliation(s)
- Ping Ye
- School of Pharmacy, The University of Queensland, Brisbane, Queensland, Australia
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Yang KM, Kim W, Bae E, Gim J, Weist BM, Jung Y, Hyun JS, Hernandez JB, Leem SH, Park T, Jeong J, Walsh CM, Kim SJ. DRAK2 participates in a negative feedback loop to control TGF-β/Smads signaling by binding to type I TGF-β receptor. Cell Rep 2012; 2:1286-99. [PMID: 23122956 DOI: 10.1016/j.celrep.2012.09.028] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 08/17/2012] [Accepted: 09/24/2012] [Indexed: 12/24/2022] Open
Abstract
TGF-β1 is a multifunctional cytokine that mediates diverse biological processes. However, the mechanisms by which the intracellular signals of TGF-β1 are terminated are not well understood. Here, we demonstrate that DRAK2 serves as a TGF-β1-inducible antagonist of TGF-β signaling. TGF-β1 stimulation rapidly induces DRAK2 expression and enhances endogenous interaction of the type I TGF-β receptor with DRAK2, thereby blocking R-Smads recruitment. Depletion of DRAK2 expression markedly augmented the intensity and the extent of TGF-β1 responses. Furthermore, a high level of DRAK2 expression was observed in basal-like and HER2-enriched breast tumors and cell lines, and depletion of DRAK2 expression suppressed the tumorigenic ability of breast cancer cells. Thus, these studies define a function for DRAK2 as an intrinsic intracellular antagonist participating in the negative feedback loop to control TGF-β1 responses, and aberrant expression of DRAK2 increases tumorigenic potential, in part, through the inhibition of TGF-β1 tumor suppressor activity.
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Affiliation(s)
- Kyung-Min Yang
- CHA Cancer Institute, CHA University of Medicine and Science, Seoul 135-081, Korea
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13
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Wu YH, Wang J, Gong DX, Gu HY, Hu SS, Zhang H. Effects of low-level laser irradiation on mesenchymal stem cell proliferation: a microarray analysis. Lasers Med Sci 2011; 27:509-19. [PMID: 21956279 DOI: 10.1007/s10103-011-0995-x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 09/12/2011] [Indexed: 12/19/2022]
Abstract
Increased proliferation after low-level laser irradiation (LLLI) has been well demonstrated in many cell types including mesenchymal stem cells (MSCs), but the exact molecular mechanisms involved remain poorly understood. The aim of this study was to investigate the change in mRNA expression in rat MSCs after LLLI and to reveal the associated molecular mechanisms. MSCs were exposed to a diode laser (635 nm) as the irradiated group. Cells undergoing the same procedure without LLLI served as the control group. Proliferation was evaluated using the MTS assay. Differences in the gene expression profiles between irradiated and control MSCs at 4 days after LLLI were analyzed using a cDNA microarray. Gene ontology and pathway analysis were used to find the key regulating genes followed by real-time PCR to validate seven representative genes from the microarray assays. This procedure identified 119 differentially expressed genes. Real-time PCR confirmed that the expression levels of v-akt murine thymoma viral oncogene homolog 1 (Akt1), the cyclin D1 gene (Ccnd1) and the phosphatidylinositol 3-kinase, catalytic alpha polypeptide gene (Pik3ca) were upregulated after LLLI, whereas those of protein tyrosine phosphatase non-receptor type 6 (Ptpn6) and serine/threonine kinase 17b (Stk17b) were downregulated. cDNA microarray analysis revealed that after LLLI the expression levels of various genes involved in cell proliferation, apoptosis and the cell cycle were affected. Five genes, including Akt1, Ptpn6, Stk17b, Ccnd1 and Pik3ca, were confirmed and the PI3K/Akt/mTOR/eIF4E pathway was identified as possibly playing an important role in mediating the effects of LLLI on the proliferation of MSCs.
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Affiliation(s)
- Yi-he Wu
- Department of Surgery, Cardiovascular Institute & Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 167 Beilishi Road, Beijing, 100037, China
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14
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Mao P, Hever MP, Niemaszyk LM, Haghkerdar JM, Yanco EG, Desai D, Beyrouthy MJ, Kerley-Hamilton JS, Freemantle SJ, Spinella MJ. Serine/threonine kinase 17A is a novel p53 target gene and modulator of cisplatin toxicity and reactive oxygen species in testicular cancer cells. J Biol Chem 2011; 286:19381-91. [PMID: 21489989 DOI: 10.1074/jbc.m111.218040] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Testicular cancer is highly curable with cisplatin-based therapy, and testicular cancer-derived human embryonal carcinoma (EC) cells undergo a p53-dominant transcriptional response to cisplatin. In this study, we have discovered that a poorly characterized member of the death-associated protein family of serine/threonine kinases, STK17A (also called DRAK1), is a novel p53 target gene. Cisplatin-mediated induction of STK17A in the EC cell line NT2/D1 was prevented with p53 siRNA. Furthermore, STK17A was induced with cisplatin in HCT116 and MCF10A cells but to a much lesser extent in isogenic p53-suppressed cells. A functional p53 response element that binds endogenous p53 in a cisplatin-dependent manner was identified 5 kb upstream of the first coding exon of STK17A. STK17A is not present in the mouse genome, but the closely related gene STK17B is induced with cisplatin in mouse NIH3T3 cells, although this induction is p53-independent. Interestingly, in human cells containing both STK17A and STK17B, only STK17A is induced with cisplatin. Knockdown of STK17A conferred resistance to cisplatin-induced growth suppression and apoptotic cell death in EC cells. This was associated with the up-regulation of detoxifying and antioxidant genes, including metallothioneins MT1H, MT1M, and MT1X that have previously been implicated in cisplatin resistance. In addition, knockdown of STK17A resulted in decreased cellular reactive oxygen species, whereas STK17A overexpression increased reactive oxygen species. In summary, we have identified STK17A as a novel direct target of p53 and a modulator of cisplatin toxicity and reactive oxygen species in testicular cancer cells.
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Affiliation(s)
- Pingping Mao
- Department of Pharmacology and Toxicology, Dartmouth Medical School, Hanover, New Hampshire 03755, USA
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15
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Newton RH, Leverrier S, Srikanth S, Gwack Y, Cahalan MD, Walsh CM. Protein kinase D orchestrates the activation of DRAK2 in response to TCR-induced Ca2+ influx and mitochondrial reactive oxygen generation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2011; 186:940-50. [PMID: 21148796 PMCID: PMC3133617 DOI: 10.4049/jimmunol.1000942] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
DRAK2 is a serine/threonine kinase highly enriched in lymphocytes that raises the threshold for T cell activation and maintains T cell survival following productive activation. T cells lacking DRAK2 are prone to activation under suboptimal conditions and exhibit enhanced calcium responses to AgR stimulation. Despite this, mice lacking DRAK2 are resistant to organ-specific autoimmune diseases due to defective autoreactive T cell survival. DRAK2 kinase activity is induced by AgR signaling, and in this study we show that the induction of DRAK2 activity requires Ca(2+) influx through the Ca(2+) release-activated Ca(2+) channel formed from Orai1 subunits. Blockade of DRAK2 activity with the protein kinase D (PKD) inhibitor Gö6976 or expression of a kinase-dead PKD mutant prevented activation of DRAK2, whereas a constitutively active PKD mutant promoted DRAK2 function. Knockdown of PKD in T cells strongly blocked endogenous DRAK2 activation following TCR ligation, implicating PKD as an essential intermediate in the activation of DRAK2 by Ca(2+) influx. Furthermore, we identify DRAK2 as a novel substrate of PKD, and demonstrate that DRAK2 and PKD physically interact under conditions that activate PKD. Mitochondrial generation of reactive oxygen intermediates was necessary and sufficient for DRAK2 activation in response to Ca(2+) influx. Taken together, DRAK2 and PKD form a novel signaling module that controls calcium homeostasis following T cell activation.
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Affiliation(s)
- Ryan H. Newton
- Institute for Immunology, University of California, Irvine, Irvine, CA 92697
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697
| | - Sabrina Leverrier
- Institute for Immunology, University of California, Irvine, Irvine, CA 92697
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697
| | - Sonal Srikanth
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095
| | - Yousang Gwack
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095
| | - Michael D. Cahalan
- Institute for Immunology, University of California, Irvine, Irvine, CA 92697
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697
| | - Craig M. Walsh
- Institute for Immunology, University of California, Irvine, Irvine, CA 92697
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697
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16
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Sironen A, Uimari P, Nagy S, Paku S, Andersson M, Vilkki J. Knobbed acrosome defect is associated with a region containing the genes STK17b and HECW2 on porcine chromosome 15. BMC Genomics 2010; 11:699. [PMID: 21143916 PMCID: PMC3016419 DOI: 10.1186/1471-2164-11-699] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Accepted: 12/09/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Male infertility is an increasing problem in all domestic species including man. Localization and identification of genes involved in defects causing male infertility provide valuable information of specific events in sperm development. Correct condensation of the sperm head and development of the acrosome are required for fertile sperm. In the Finnish Yorkshire pig population a knobbed acrosome defect (KAD) has been reported which appears to be of genetic origin. In previous studies we have shown that a large number of affected spermatozoa have a cystic swelling anterior to the apical part of the acrosome. RESULTS Characterization of the knobbed acrosome affected sperm revealed that both the acrosomal granules and chromatin are affected. This type of KAD appears to be a previously unknown and serious form of the defect. A genome wide scan with PorcineSNP60 Genotyping BeadChip defined the KAD associated region within 0.7 Mbp on porcine chromosome 15. Two genes, STK17b and HECW2, located within this region were sequenced. The expression of these genes appeared comparable in KA-affected and control boars. The known function of HECW2 in acrosome development highlighted this gene as a good candidate responsible for the KAD. One nonsynonymous SNP was identified within the HECW2 gene. However, as this mutation was found in homozygous state in individuals with normal sperm, this is not likely to be the causal mutation. CONCLUSIONS In this study we identified two candidate genes for a severe defect affecting both the sperm acrosome and chromatin that causes infertility. One of these genes, HECW2, plays an important role in ubiquitination, a prerequisite for chromatin remodelling and acrosome formation, highlighting the involvement of this gene in the knobbed acrosome defect and male infertility.
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Affiliation(s)
- Anu Sironen
- Agrifood Research Finland, MTT, Biotechnology and Food Research, Genomics, FI-36100 Jokioinen, Finland.
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17
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Araki S, Nakayama Y, Hori A, Yoshimura K. Biomarkers for predicting the sensitivity of cancer cells to TRAIL-R1 agonistic monoclonal antibody. Cancer Lett 2010; 292:269-79. [PMID: 20056315 DOI: 10.1016/j.canlet.2009.12.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 12/10/2009] [Accepted: 12/11/2009] [Indexed: 11/28/2022]
Abstract
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and an agonistic monoclonal antibody to TRAIL-R1 (TRAIL-R1 mAb) induce apoptosis and show anti-proliferative activity in vitro and in vivo. However, some TRAIL-R1-expressing cell lines are not sensitive to either TRAIL-R1 mAb or TRAIL. We have identified four genes (STK17B, SP140L, CASP8, and AIM1) whose expression levels differ significantly between TRAIL-R1 mAb-sensitive and resistant cell lines. Using the expression levels of these genes, we predicted TRAIL-R1 mAb and TRAIL sensitivity in our test cell lines with 75% (9/12) and 84% (21/25) accuracy, respectively. Knockdown of STK17B in TRAIL-R1 mAb-sensitive cells augmented Bcl-2 expression and suppressed TRAIL-R1 mAb-induced apoptosis. Our results may be useful for predicting the response of cancers to TRAIL-agonistic drugs in the clinic.
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Affiliation(s)
- Shinsuke Araki
- Pharmaceutical Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 10 Wadai, Tsukuba, Ibaraki 300-4293, Japan
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18
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Increased synthetic phenotype behavior of smooth muscle cells in response to in vitro balloon angioplasty injury model. Ann Vasc Surg 2009; 24:116-26. [PMID: 19781909 DOI: 10.1016/j.avsg.2009.07.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 06/17/2009] [Accepted: 07/12/2009] [Indexed: 11/20/2022]
Abstract
Restenosis remains a common problem following balloon angioplasty, and it has been speculated that changes in the mechanical environment due to endovascular interventions are correlated with shifts in smooth muscle cell (SMC) phenotype. In order to study SMC response to forces similar to those exerted during balloon angioplasty, an in vitro concurrent shear and tensile forces simulator has been developed. After 24 hr of exposure to cyclic tension (5%) and shear (0.1-0.5 dynes/cm(2)) following simulated angioplasty injury (12% stretch), rat aortic SMCs exhibited significant synthetic behavior. These responses included increased cell proliferation, apoptosis, and cell hypertrophy compared to cells exposed to strain alone. While all SMCs exposed to dynamic stimuli (strain, strain+balloon injury, strain+balloon injury+shear) demonstrated a decrease in contractile protein expression, the injury group also exhibited significantly greater expression of the synthetic marker vimentin. These in vitro findings agree with in vivo events following balloon angioplasty and present a refined dynamic model to be implemented for better understanding of SMC activation and prevention of responses through pharmacological treatment.
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19
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Doherty GA, Byrne SM, Austin SC, Scully GM, Sadlier DM, Neilan TG, Kay EW, Murray FE, Fitzgerald DJ. Regulation of the apoptosis-inducing kinase DRAK2 by cyclooxygenase-2 in colorectal cancer. Br J Cancer 2009; 101:483-91. [PMID: 19638987 PMCID: PMC2720240 DOI: 10.1038/sj.bjc.6605144] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Background: Cyclooxygenase-2 (COX-2) is over-expressed in colorectal cancer (CRC), rendering tumour cells resistant to apoptosis. Selective COX-2 inhibition is effective in CRC prevention, although having adverse cardiovascular effects, thus focus has shifted to downstream pathways. Methods: Microarray experiments identified genes regulated by COX-2 in HCA7 CRC cells. In vitro and in vivo regulation of DRAK2 (DAP kinase-related apoptosis-inducing kinase 2 or STK17β, an apoptosis-inducing kinase) by COX-2 was validated by qRT-PCR. Results: Inhibition of COX-2 induced apoptosis and enhanced DRAK2 expression in HCA7 cells (4.4-fold increase at 4 h by qRT-PCR, P=0.001), an effect prevented by co-administration of PGE2. DRAK2 levels were suppressed in a panel of human colorectal tumours (n=10) compared to normal mucosa, and showed inverse correlation with COX-2 expression (R=−0.68, R2=0.46, P=0.03). Administration of the selective COX-2 inhibitor rofecoxib to patients with CRC (n=5) induced DRAK2 expression in tumours (2.5-fold increase, P=0.01). In vitro silencing of DRAK2 by RNAi enhanced CRC cell survival following COX-2 inhibitor treatment. Conclusion: DRAK2 is a serine–threonine kinase implicated in the regulation of apoptosis and is negatively regulated by COX-2 in vitro and in vivo, suggesting a novel mechanism for the effect of COX-2 on cancer cell survival.
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Affiliation(s)
- G A Doherty
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland.
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20
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Hamaishi M, Orihashi K, Isaka M, Kumagai H, Takahashi S, Okada K, Ohtaki M, Sueda T. Low-Dose Edaravone Injection into the Clamped Aorta Prevents Ischemic Spinal Cord Injury. Ann Vasc Surg 2009; 23:128-35. [DOI: 10.1016/j.avsg.2008.05.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2008] [Revised: 05/18/2008] [Accepted: 05/19/2008] [Indexed: 11/16/2022]
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21
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McGargill MA, Choy C, Wen BG, Hedrick SM. Drak2 regulates the survival of activated T cells and is required for organ-specific autoimmune disease. THE JOURNAL OF IMMUNOLOGY 2008; 181:7593-605. [PMID: 19017948 DOI: 10.4049/jimmunol.181.11.7593] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Drak2 is a serine/threonine kinase expressed in T and B cells. The absence of Drak2 renders T cells hypersensitive to suboptimal stimulation, yet Drak2(-/-) mice are enigmatically resistant to experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis. We show in this study that Drak2(-/-) mice were also completely resistant to type 1 diabetes when bred to the NOD strain of mice that spontaneously develop autoimmune diabetes. However, there was not a generalized suppression of the immune system, because Drak2(-/-) mice remained susceptible to other models of autoimmunity. Adoptive transfer experiments revealed that resistance to disease was intrinsic to the T cells and was due to a loss of T cell survival under conditions of chronic autoimmune stimulation. Importantly, the absence of Drak2 did not alter the survival of naive T cells, memory T cells, or T cells responding to an acute viral infection. These experiments reveal a distinction between the immune response to persistent self-encoded molecules and transiently present infectious agents. We present a model whereby T cell survival depends on a balance of TCR and costimulatory signals to explain how the absence of Drak2 affects autoimmune disease without generalized suppression of the immune system.
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Affiliation(s)
- Maureen A McGargill
- Department of Cellular and Molecular Medicine, Division of Biological Sciences, Molecular Biology Section, University of California, San Diego, La Jolla, CA 92093, USA
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22
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Al-Qahtani A, Xu Z, Zan H, Walsh CM, Casali P. A role for DRAK2 in the germinal center reaction and the antibody response. Autoimmunity 2008; 41:341-52. [PMID: 18568639 DOI: 10.1080/08916930802170633] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
DAP-related apoptotic kinase-2 (DRAK2), a death-associated protein kinase family member, is highly expressed in B and T lymphocytes in the human and the mouse. To determine whether DRAK2 plays a role in B-cell activation and differentiation, we analyzed germinal centers (GCs) and the specific antibody response to NP in drak2-/- mice immunized with the thymus-dependent (TD) conjugated hapten NP16-CGG. In drak2-/- mice, spleen GCs were normal in size and morphology, but their number was reduced by as much as 5-fold, as compared to their wild-type littermates. This was not due to a defect in B-cell proliferation, as the BrdU uptake was comparable in DRAK2-deficient and wild-type B cells. Rather, the proportion of apoptotic GC B and T cells in drak2-/- mice was significantly higher than that in wild-type control mice, as shown by 7-AAD and terminal deoxynucleotide transferase dUTP nick end labeling (TUNEL) staining. In drak2-/- mice, the generation high affinity IgG antibodies was impaired in spite of the seemingly normal somatic hypermutation and class switch DNA recombination machineries in drak2-/- B cells. In NP16-CGG-immunized drak2-/- mice, T-cell-intrinsic Bcl-xL transgene expression increased the number of GCs and rescued the high affinity IgG response to NP. These findings suggest a novel role for DRAK2 in regulating the GC reaction and the response to TD antigens, perhaps through increased survival of T cells and enhanced B-cell positive selection. They also suggest that DRAK2-deficiency is not involved in regulating intrinsic B-cell apoptosis.
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Affiliation(s)
- Ahmed Al-Qahtani
- Center for Immunology, University of California, Irvine, CA, USA
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23
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Desharnais P, Dupéré-Minier G, Hamelin C, Devine P, Bernier J. Involvement of CD45 in DNA fragmentation in apoptosis induced by mitochondrial perturbing agents. Apoptosis 2008; 13:197-212. [PMID: 18157742 DOI: 10.1007/s10495-007-0162-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
CD45 is a type I transmembrane molecule with phosphatase activity which comprises up to 10% of the cell surface area in nucleated haematopoietic cells. We have previously demonstrated the absence of nuclear apoptosis in CD45-negative T cells after chemical-induced apoptosis. The aim of this study was to characterize the role of CD45 in nuclear apoptosis. In contrast to wild type CD45-positive T cells, the CD45-deficient T cell lines are resistant to the induction of DNA fragmentation and chromatin condensation following tributyltin (TBT) or H2O2 exposure, but not to cycloheximide-induced apoptosis. CD45 transfection in deficient cell lines led to the restoration of chromatin condensation and DNA fragmentation following TBT exposure. In both CD45-positive and negative T cell lines, TBT exposure mediates intracellular calcium mobilization, caspase-3 activation and DFF45 cleavage. Moreover, DNA fragmentation was also induced by TBT in cells deficient in expression of p56lck, ZAP-70 and SHP-1. Subcellular partitioning showed a decrease in nuclear localisation of caspase-3 and DFF40. Together, these results demonstrate for the first time, that CD45 expression plays a key role in internucleosomal DNA fragmentation and chromatin condensation processes during apoptosis. CD45 activity or its substrates' activity, appears to be located downstream of caspase-3 activation and plays a role in retention of DFF40 in the nucleus.
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Affiliation(s)
- Philippe Desharnais
- INRS-Institut Armand-Frappier, 531 boul. des Prairies, Laval, QC, Canada, H7V 1B7
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24
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Stover J, Nagatomi J. Cyclic Pressure Stimulates DNA Synthesis through the PI3K/Akt Signaling Pathway in Rat Bladder Smooth Muscle Cells. Ann Biomed Eng 2007; 35:1585-94. [PMID: 17522977 DOI: 10.1007/s10439-007-9331-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Accepted: 05/14/2007] [Indexed: 11/27/2022]
Abstract
Previous studies demonstrated that the bladder exhibited severe tissue remodeling following spinal cord injury. In such pathological bladders, uninhibited non-voiding contractions subject bladder cells to cyclic oscillations of intravesical pressure. We hypothesize that cyclic pressure is a potential trigger for tissue remodeling in overactive bladder. Using a custom-made setup, rat bladder smooth muscle cells (SMC) in vitro were exposed to cyclic hydrostatic pressure (40 cm H2O) at either 0.1 Hz or 0.02 Hz frequency for up to 24 h. When compared to static control and cells exposed to 0.02-Hz cyclic pressure, SMC exposed to 0.1-Hz cyclic pressure contained significantly (p < 0.05) higher amounts of DNA. We confirmed that the increase in DNA was due to increased cell proliferation, indicated by increased BrdU incorporation, but not due to decreased apoptosis rates in response to cyclic pressure. In addition, significant (p < 0.05) elevation of Akt phosphorylation in SMC following exposure to cyclic pressure and lack of pressure-induced SMC hyperplasia in the presence of PI3K inhibitors, wortmannin and LY294002, indicated the involvement of the PI3K/Akt pathway in the proliferative response of SMC to cyclic pressure. We concluded that chronic exposure to intravesical pressure oscillation may be a potential trigger for bladder tissue remodeling.
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Affiliation(s)
- Joshua Stover
- Department of Bioengineering, Clemson University, 501 Rhodes Engineering Research Center, Clemson, SC 29634-0905, USA
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