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Kang PW, Woodbury L, Angsutararux P, Sambare N, Shi J, Marras M, Abella C, Bedi A, Zinn D, Cui J, Silva JR. Arrhythmia-associated calmodulin variants interact with KCNQ1 to confer aberrant membrane trafficking and function. PNAS Nexus 2023; 2:pgad335. [PMID: 37965565 PMCID: PMC10642763 DOI: 10.1093/pnasnexus/pgad335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 10/04/2023] [Indexed: 11/16/2023]
Abstract
Missense variants in calmodulin (CaM) predispose patients to arrhythmias associated with high mortality rates ("calmodulinopathy"). As CaM regulates many key cardiac ion channels, an understanding of disease mechanism associated with CaM variant arrhythmias requires elucidating individual CaM variant effects on distinct channels. One key CaM regulatory target is the KCNQ1 (KV7.1) voltage-gated potassium channel that carries the IKs current. Yet, relatively little is known as to how CaM variants interact with KCNQ1 or affect its function. Here, we take a multipronged approach employing a live-cell fluorescence resonance energy transfer binding assay, fluorescence trafficking assay, and functional electrophysiology to characterize >10 arrhythmia-associated CaM variants for effect on KCNQ1 CaM binding, membrane trafficking, and channel function. We identify one variant (G114W) that exhibits severely weakened binding to KCNQ1 but find that most other CaM variants interact with similar binding affinity to KCNQ1 when compared with CaM wild-type over physiological Ca2+ ranges. We further identify several CaM variants that affect KCNQ1 and IKs membrane trafficking and/or baseline current activation kinetics, thereby delineating KCNQ1 dysfunction in calmodulinopathy. Lastly, we identify CaM variants with no effect on KCNQ1 function. This study provides extensive functional data that reveal how CaM variants contribute to creating a proarrhythmic substrate by causing abnormal KCNQ1 membrane trafficking and current conduction. We find that CaM variant regulation of KCNQ1 is not uniform with effects varying from benign to significant loss of function, suggesting how CaM variants predispose patients to arrhythmia via the dysregulation of multiple cardiac ion channels. Classification: Biological, Health, and Medical Sciences, Physiology.
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Affiliation(s)
- Po wei Kang
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Lucy Woodbury
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Paweorn Angsutararux
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Namit Sambare
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Jingyi Shi
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Martina Marras
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Carlota Abella
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Anish Bedi
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - DeShawn Zinn
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Jianmin Cui
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Jonathan R Silva
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
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Kang PW, Woodbury L, Angsutararux P, Sambare N, Shi J, Marras M, Abella C, Bedi A, Zinn D, Cui J, Silva JR. Arrhythmia-associated Calmodulin Variants Interact with KCNQ1 to Confer Aberrant Membrane Trafficking and Function. bioRxiv 2023:2023.01.28.526031. [PMID: 36747728 PMCID: PMC9900995 DOI: 10.1101/2023.01.28.526031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Rationale Missense variants in calmodulin (CaM) predispose patients to arrhythmias associated with high mortality rates. As CaM regulates several key cardiac ion channels, a mechanistic understanding of CaM variant-associated arrhythmias requires elucidating individual CaM variant effect on distinct channels. One key CaM regulatory target is the KCNQ1 (K V 7.1) voltage-gated potassium channel that underlie the I Ks current. Yet, relatively little is known as to how CaM variants interact with KCNQ1 or affect its function. Objective To observe how arrhythmia-associated CaM variants affect binding to KCNQ1, channel membrane trafficking, and KCNQ1 function. Methods and Results We combine a live-cell FRET binding assay, fluorescence trafficking assay, and functional electrophysiology to characterize >10 arrhythmia-associated CaM variants effect on KCNQ1. We identify one variant (G114W) that exhibits severely weakened binding to KCNQ1 but find that most other CaM variants interact with similar binding affinity to KCNQ1 when compared to CaM wild-type over physiological Ca 2+ ranges. We further identify several CaM variants that affect KCNQ1 and I Ks membrane trafficking and/or baseline current activation kinetics, thereby contextualizing KCNQ1 dysfunction in calmodulinopathy. Lastly, we delineate CaM variants with no effect on KCNQ1 function. Conclusions This study provides comprehensive functional data that reveal how CaM variants contribute to creating a pro-arrhythmic substrate by causing abnormal KCNQ1 membrane trafficking and current conduction. We find that CaM variant regulation of KCNQ1 is not uniform with effects varying from benign to significant loss of function. This study provides a new approach to collecting details of CaM binding that are key for understanding how CaM variants predispose patients to arrhythmia via the dysregulation of multiple cardiac ion channels.
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3
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Wei Kang P, Woodbury LS, Angsutararux P, Sambare N, Shi J, Marras M, Abella C, Bedi A, Zinn D, Cui J, Silva JR. Disease associated CaM variants interact with KCNQ1 to confer aberrant membrane trafficking and function. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.1549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Falkowski AL, Jacobson JA, Cresswell M, Bedi A, Kalia V. Medial Meniscal Extrusion Evaluated with Weight-Bearing Ultrasound in Correlation with MRI: Differences in Meniscal Morphologies and Patient Symptoms. Semin Musculoskelet Radiol 2021. [DOI: 10.1055/s-0041-1731552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Uy M, Wang J, Horner NS, Bedi A, Leroux T, Alolabi B, Khan M. Cemented humeral stem versus press-fit humeral stem in total shoulder arthroplasty: a systematic review and meta-analysis. Bone Joint J 2019; 101-B:1107-1114. [PMID: 31474140 DOI: 10.1302/0301-620x.101b9.bjj-2018-1369.r1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
AIMS The aim of this study was to evaluate the differences in revision and complication rates, functional outcomes, and radiological outcomes between cemented and press-fit humeral stems in primary anatomical total shoulder arthroplasty (TSA). MATERIALS AND METHODS A comprehensive systematic review and meta-analysis was conducted searching for studies that included patients who underwent primary anatomical TSA for primary osteoarthritis or rheumatoid arthritis. RESULTS There was a total of 36 studies with 927 cemented humeral stems and 1555 press-fit stems. The revision rate was 5.4% (95% confidence interval (CI) 3.9 to 7.4) at a mean of 89 months for cemented stems, and 2.4% (95% CI 1.1 to 4.7) at a mean of 40 months for press-fit stems. A priori subgroup analysis to control for follow-up periods demonstrated similar revision rates: 2.3% (95% CI 1.1 to 4.7) for cemented stems versus 1.8% (95% CI 1.4 to 2.9) for press-fit stems. Exploratory meta-regression found that longer follow-up was a moderating variable for revision (p = 0.003). CONCLUSION Cement fixation had similar revision rates when compared to press-fit stems at short- to midterm follow-up. Rotator cuff pathology was a prevalent complication in both groups but is likely not related to fixation type. Overall, with comparable revision rates, possible easier revision, and decreased operative time, humeral press-fit fixation may be an optimal choice for primary anatomical TSA in patients with sufficient bone stock. Cite this article: Bone Joint J 2019;101-B:1107-1114.
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Affiliation(s)
- M Uy
- Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Canada
| | - J Wang
- Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Canada
| | - N S Horner
- Division of Orthopaedic Surgery, Department of Surgery, McMaster University, Hamilton, Canada
| | - A Bedi
- MedSport, University of Michigan, Ann Arbor, Michigan, USA
| | - T Leroux
- Division of Orthopaedic Surgery, Department of Surgery, University of Toronto, Toronto, Canada
| | - B Alolabi
- Division of Orthopaedic Surgery, Department of Surgery, McMaster University, Hamilton, Canada
| | - M Khan
- Division of Orthopaedic Surgery, Department of Surgery, McMaster University, Hamilton, Canada
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Kundapur P, Bedi A. A234 INTER AND INTRA RATER RELIABILITY OF PHOTO DOCUMENTATION IN COLONOSCOPY. J Can Assoc Gastroenterol 2019. [DOI: 10.1093/jcag/gwz006.233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- P Kundapur
- Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - A Bedi
- Medicine, University of Saskatchewan, Saskatoon, SK, Canada
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Izumchenko E, Paz K, Ciznadija D, Sloma I, Katz A, Vasquez-Dunddel D, Ben-Zvi I, Stebbing J, McGuire W, Harris W, Maki R, Gaya A, Bedi A, Zacharoulis S, Ravi R, Wexler LH, Hoque MO, Rodriguez-Galindo C, Pass H, Peled N, Davies A, Morris R, Hidalgo M, Sidransky D. Patient-derived xenografts effectively capture responses to oncology therapy in a heterogeneous cohort of patients with solid tumors. Ann Oncol 2018; 28:2595-2605. [PMID: 28945830 DOI: 10.1093/annonc/mdx416] [Citation(s) in RCA: 193] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Background While patient-derived xenografts (PDXs) offer a powerful modality for translational cancer research, a precise evaluation of how accurately patient responses correlate with matching PDXs in a large, heterogeneous population is needed for assessing the utility of this platform for preclinical drug-testing and personalized patient cancer treatment. Patients and methods Tumors obtained from surgical or biopsy procedures from 237 cancer patients with a variety of solid tumors were implanted into immunodeficient mice and whole-exome sequencing was carried out. For 92 patients, responses to anticancer therapies were compared with that of their corresponding PDX models. Results We compared whole-exome sequencing of 237 PDX models with equivalent information in The Cancer Genome Atlas database, demonstrating that tumorgrafts faithfully conserve genetic patterns of the primary tumors. We next screened PDXs established for 92 patients with various solid cancers against the same 129 treatments that were administered clinically and correlated patient outcomes with the responses in corresponding models. Our analysis demonstrates that PDXs accurately replicate patients' clinical outcomes, even as patients undergo several additional cycles of therapy over time, indicating the capacity of these models to correctly guide an oncologist to treatments that are most likely to be of clinical benefit. Conclusions Integration of PDX models as a preclinical platform for assessment of drug efficacy may allow a higher success-rate in critical end points of clinical benefit.
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Affiliation(s)
- E Izumchenko
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, R&D, Baltimore
| | - K Paz
- Champions Oncology, R&D, Baltimore, USA
| | | | - I Sloma
- Champions Oncology, R&D, Baltimore, USA
| | - A Katz
- Champions Oncology, R&D, Baltimore, USA
| | | | - I Ben-Zvi
- Champions Oncology, R&D, Baltimore, USA
| | - J Stebbing
- Department of Surgery & Cancer, Imperial College, London, UK
| | - W McGuire
- Department of Internal Medicine, Division of Hematology/Oncology, Virginia Commonwealth University, Massey Cancer Center, Virginia Commonwealth University, Richmond
| | - W Harris
- Department of Medicine, Division of Oncology, University of Washington, Seattle
| | - R Maki
- Department of Pediatric Hematology Oncology, Mount Sinai School of Medicine, New York, USA
| | - A Gaya
- Guy's and St Thomas' Cancer Center, London
| | - A Bedi
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, R&D, Baltimore
| | - S Zacharoulis
- Department of Pediatric Oncology, The Royal Marsden Hospital, Harley Street Clinic, Sutton, UK
| | - R Ravi
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, R&D, Baltimore
| | - L H Wexler
- Department of Pediatrics, Memorial Sloan-Kettering Cancer Center, New York
| | - M O Hoque
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, R&D, Baltimore
| | | | - H Pass
- Department of Cardiothoracic Surgery, New York University Langone Medical Center, New York, USA
| | - N Peled
- Research and Detection Unit for Thoracic malignancies, Sheba Medical Center, Tel Aviv, Israel
| | - A Davies
- Champions Oncology, R&D, Baltimore, USA
| | - R Morris
- Champions Oncology, R&D, Baltimore, USA
| | - M Hidalgo
- Division of Hematology-Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, USA
| | - D Sidransky
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, R&D, Baltimore.
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8
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Wishart E, Block H, Bedi A. A240 AN UNUSUAL PRESENTATION OF HEPATIC ENCEPHALOPATHY: RECURRENT GLOBAL APHASIA. J Can Assoc Gastroenterol 2018. [DOI: 10.1093/jcag/gwy008.241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- E Wishart
- University of Saskatchewan, Saskatoon, SK, Canada
| | - H Block
- University of Saskatchewan, Saskatoon, SK, Canada
| | - A Bedi
- University of Saskatchewan, Saskatoon, SK, Canada
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9
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Maerz T, Fleischer M, Newton MD, Davidson A, Salisbury M, Altman P, Kurdziel MD, Anderson K, Bedi A, Baker KC. Acute mobilization and migration of bone marrow-derived stem cells following anterior cruciate ligament rupture. Osteoarthritis Cartilage 2017; 25:1335-1344. [PMID: 28284998 DOI: 10.1016/j.joca.2017.03.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 02/21/2017] [Accepted: 03/01/2017] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Little is known regarding acute local and systemic processes following anterior cruciate ligament (ACL) rupture. No study has elucidated whether bone marrow-derived mesenchymal stem cells (MSCs) are mobilized into circulation and recruited to the injured joint. METHODS In Part 1, Lewis rats were randomized to noninvasive ACL rupture (Rupture) or non-injured (Control) (n = 6/group). After 72 h, whole blood MSC concentration was assessed using flow cytometry. Synovial fluid and serum were assayed for stromal cell-derived factor (SDF)-1α and cartilage degeneration biomarkers, respectively. In Part 2, 12 additional rats were randomized and intravenously-injected with fluorescently-labeled allogenic MSCs. Cell tracking was performed using longitudinal, in vivo and ex vivo near-infrared (NIR) imaging and histology. Synovium SDF-1α and interleukin (IL)-17A immunostaining was performed. Serum was assayed for SDF-1α and 29 other cytokines. RESULTS In Part 1, there was a significant increase in MSC concentration and synovial fluid SDF-1α in Rupture. No differences in cartilage biomarkers were observed. In Part 2, Rupture had significantly higher NIR signal at 24, 48, and 72 h, indicating active recruitment of MSCs to the injured joint. Ex vivo cell tracking demonstrated MSC localization in the synovium and myotendinous junction (MTJ) of the quadriceps. Injured synovia exhibited increased synovitis grade and higher degree of IL-17A and SDF-1α immunostaining. CONCLUSION ACL rupture induced peripheral blood mobilization of MSCs and migration of intravenously-injected allogenic MSCs to the injured joint, where they localized in the synovium and quadriceps MTJ.
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Affiliation(s)
- T Maerz
- Orthopaedic Research Laboratory, Beaumont Health, Royal Oak, MI, USA; Department of Orthopaedic Surgery, Oakland University - William Beaumont School of Medicine, Rochester, MI, USA
| | - M Fleischer
- Orthopaedic Research Laboratory, Beaumont Health, Royal Oak, MI, USA
| | - M D Newton
- Orthopaedic Research Laboratory, Beaumont Health, Royal Oak, MI, USA
| | - A Davidson
- Orthopaedic Research Laboratory, Beaumont Health, Royal Oak, MI, USA
| | - M Salisbury
- Orthopaedic Research Laboratory, Beaumont Health, Royal Oak, MI, USA
| | - P Altman
- Department of Orthopaedic Surgery, Beaumont Health, Royal Oak, MI, USA
| | - M D Kurdziel
- Orthopaedic Research Laboratory, Beaumont Health, Royal Oak, MI, USA; Department of Orthopaedic Surgery, Oakland University - William Beaumont School of Medicine, Rochester, MI, USA
| | - K Anderson
- Department of Orthopaedic Surgery, Oakland University - William Beaumont School of Medicine, Rochester, MI, USA; Department of Orthopaedic Surgery, Beaumont Health, Royal Oak, MI, USA
| | - A Bedi
- MedSport and Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI, USA
| | - K C Baker
- Orthopaedic Research Laboratory, Beaumont Health, Royal Oak, MI, USA; Department of Orthopaedic Surgery, Oakland University - William Beaumont School of Medicine, Rochester, MI, USA.
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Van Den Eede MP, Bedi A, Delabie J, De Winter J, Gerbaux P, Koeckelberghs G. The influence of the end-group on the chiral self-assembly of all-conjugated block copolymers. Polym Chem 2017. [DOI: 10.1039/c7py01043e] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
This research demonstrates the influence of the end-group on the self-assembly of conjugated polymers.
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Affiliation(s)
| | - A. Bedi
- Laboratory for Polymer Synthesis
- KU Leuven
- B-3001 Heverlee
- Belgium
| | - J. Delabie
- Laboratory for Polymer Synthesis
- KU Leuven
- B-3001 Heverlee
- Belgium
| | - J. De Winter
- Organic Synthesis and Mass Spectrometry Laboratory
- Interdisciplinary Center for Mass Spectrometry
- University of Mons-UMONS
- 7000 Mons
- Belgium
| | - P. Gerbaux
- Organic Synthesis and Mass Spectrometry Laboratory
- Interdisciplinary Center for Mass Spectrometry
- University of Mons-UMONS
- 7000 Mons
- Belgium
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11
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Gumucio JP, Flood MD, Bedi A, Kramer HF, Russell AJ, Mendias CL. Inhibition of prolyl 4-hydroxylase decreases muscle fibrosis following chronic rotator cuff tear. Bone Joint Res 2017; 6:57-65. [PMID: 28108482 PMCID: PMC5301902 DOI: 10.1302/2046-3758.61.bjr-2016-0232.r1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Accepted: 11/21/2016] [Indexed: 11/16/2022] Open
Abstract
Objectives Rotator cuff tears are among the most frequent upper extremity injuries. Current treatment strategies do not address the poor quality of the muscle and tendon following chronic rotator cuff tears. Hypoxia-inducible factor-1 alpha (HIF-1α) is a transcription factor that activates many genes that are important in skeletal muscle regeneration. HIF-1α is inhibited under normal physiological conditions by the HIF prolyl 4-hydroxylases (PHDs). In this study, we used a pharmacological PHD inhibitor, GSK1120360A, to enhance the activity of HIF-1α following the repair of a chronic cuff tear, and measured muscle fibre contractility, fibrosis, gene expression, and enthesis mechanics. Methods Chronic supraspinatus tears were induced in adult rats, and repaired 28 days later. Rats received 0 mg/kg, 3 mg/kg, or 10 mg/kg GSK1120360A daily. Collagen content, contractility, fibre type distribution and size, the expression of genes involved in fibrosis, lipid accumulation, atrophy and inflammation, and the mechanical properties of the enthesis were then assessed two weeks following surgical repair. Results At two weeks following repair, treatment groups showed increased muscle mass but there was a 15% decrease in force production in the 10 mg/kg group from controls, and no difference between the 0 mg/kg and the 3 mg/kg groups. There was a decrease in the expression of several gene transcripts related to matrix accumulation and fibrosis, and a 50% decrease in collagen content in both treated groups compared with controls. Additionally, the expression of inflammatory genes was reduced in the treated groups compared with controls. Finally, PHD inhibition improved the maximum stress and displacement to failure in repaired tendons. Conclusions GSK1120360A resulted in improved enthesis mechanics with variable effects on muscle function. PHD inhibition may be beneficial for connective tissue injuries in which muscle atrophy has not occurred. Cite this article: J. P. Gumucio, M. D. Flood, A. Bedi, H. F. Kramer, A. J. Russell, C. L. Mendias. Inhibition of prolyl 4-hydroxylase decreases muscle fibrosis following chronic rotator cuff tear. Bone Joint Res 2017;6:57–65. DOI: 10.1302/2046-3758.61.BJR-2016-0232.R1.
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Affiliation(s)
- J P Gumucio
- Departments of Orthopaedic Surgery and Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - M D Flood
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - A Bedi
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - H F Kramer
- Muscle Metabolism DPU, GlaxoSmithKline Pharmaceuticals, Muscle Metabolism DPU, King of Prussia, Pennsylvania, USA
| | - A J Russell
- Muscle Metabolism DPU, GlaxoSmithKline Pharmaceuticals, Muscle Metabolism DPU, King of Prussia, Pennsylvania, USA
| | - C L Mendias
- Departments of Orthopaedic Surgery and Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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Izumchenko E, Meir J, Bedi A, Wysocki PT, Hoque MO, Sidransky D. Patient-derived xenografts as tools in pharmaceutical development. Clin Pharmacol Ther 2016; 99:612-21. [PMID: 26874468 DOI: 10.1002/cpt.354] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 02/20/2016] [Accepted: 02/11/2016] [Indexed: 12/16/2022]
Abstract
Successful drug development in oncology is grossly suboptimal, manifested by the very low percentage of new agents being developed that ultimately succeed in clinical approval. This poor success is in part due to the inability of standard cell-line xenograft models to accurately predict clinical success and to tailor chemotherapy specifically to a group of patients more likely to benefit from the therapy. Patient-derived xenografts (PDXs) maintain the histopathological architecture and molecular features of human tumors, and offer a potential solution to maximize drug development success and ultimately generate better outcomes for patients. Although imperfect in mimicking all aspects of human cancer, PDXs are a more predictable platform for preclinical evaluation of treatment effect and in selected cases can guide therapeutic decision making in the clinic. This article summarizes the current status of PDX models, challenges associated with modeling human cancer, and various approaches that have been applied to overcome these challenges and improve the clinical relevance of PDX cancer models.
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Affiliation(s)
- E Izumchenko
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - J Meir
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - A Bedi
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - P T Wysocki
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - M O Hoque
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - D Sidransky
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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13
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Ross JR, Bedi A, Stone RM, Sibilsky Enselman E, Leunig M, Kelly BT, Larson CM. Corrigendum. Intraoperative fluoroscopic imaging to treat cam deformities: correlation with 3-dimensional computed tomography. Am J Sports Med 2015; 43:NP27. [PMID: 26232462 DOI: 10.1177/0363546515597653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ross JR, Bedi A, Stone RM, Sibilsky Enselman E, Leunig M, Kelly BT, Larson CM. Intraoperative fluoroscopic imaging to treat cam deformities: correlation with 3-dimensional computed tomography. Am J Sports Med. 2014;42(6):1370-1376. (Original DOI: 10.1177/0363546514529515 )
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14
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Gumucio J, Flood M, Harning J, Phan A, Roche S, Lynch E, Bedi A, Mendias C. T lymphocytes are not required for the development of fatty degeneration after rotator cuff tear. Bone Joint Res 2014; 3:262-72. [PMID: 25185444 PMCID: PMC4220170 DOI: 10.1302/2046-3758.39.2000294] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Objectives Rotator cuff tears are among the most common and debilitating
upper extremity injuries. Chronic cuff tears result in atrophy and
an infiltration of fat into the muscle, a condition commonly referred
to as ‘fatty degeneration’. While stem cell therapies hold promise
for the treatment of cuff tears, a suitable immunodeficient animal
model that could be used to study human or other xenograft-based
therapies for the treatment of rotator cuff injuries had not previously
been identified. Methods A full-thickness, massive supraspinatus and infraspinatus tear
was induced in adult T-cell deficient rats. We hypothesised that,
compared with controls, 28 days after inducing a tear we would observe
a decrease in muscle force production, an accumulation of type IIB
fibres, and an upregulation in the expression of genes involved
with muscle atrophy, fibrosis and inflammation. Results Chronic cuff tears in nude rats resulted in a 30% to 40% decrease
in muscle mass, a 23% reduction in production of muscle force, and
an induction of genes that regulate atrophy, fibrosis, lipid accumulation,
inflammation and macrophage recruitment. Marked large lipid droplet
accumulation was also present. Conclusions The extent of degenerative changes in nude rats was similar to
what was observed in T-cell competent rats. T cells may not play
an important role in regulating muscle degeneration following chronic
muscle unloading. The general similarities between nude and T-cell
competent rats suggest the nude rat is likely an appropriate preclinical
model for the study of xenografts that have the potential to enhance
the treatment of chronically torn rotator cuff muscles. Cite this article: Bone Joint Res 2014;3:262–72.
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Affiliation(s)
- J Gumucio
- University of Michigan, Department of Orthopaedic Surgery, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Michigan, 48109-2200, USA
| | - M Flood
- University of Michigan, Department of Orthopaedic Surgery, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Michigan, 48109-2200, USA
| | - J Harning
- University of Michigan, Department of Orthopaedic Surgery, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Michigan, 48109-2200, USA
| | - A Phan
- University of Michigan, Department of Orthopaedic Surgery, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Michigan, 48109-2200, USA
| | - S Roche
- University of Michigan, Department of Orthopaedic Surgery, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Michigan, 48109-2200, USA
| | - E Lynch
- University of Michigan, Department of Orthopaedic Surgery, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Michigan, 48109-2200, USA
| | - A Bedi
- University of Michigan, Department of Orthopaedic Surgery, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Michigan, 48109-2200, USA
| | - C Mendias
- University of Michigan, Department of Orthopaedic Surgery, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, Michigan, 48109-2200, USA
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15
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Abstract
The technical advances in arthroscopic surgery of the hip, including the improved ability to manage the capsule and gain extensile exposure, have been paralleled by a growth in the number of conditions that can be addressed. This expanding list includes symptomatic labral tears, chondral lesions, injuries of the ligamentum teres, femoroacetabular impingement (FAI), capsular laxity and instability, and various extra-articular disorders, including snapping hip syndromes. With a careful diagnostic evaluation and technical execution of well-indicated procedures, arthroscopic surgery of the hip can achieve successful clinical outcomes, with predictable improvements in function and pre-injury levels of physical activity for many patients. This paper reviews the current position in relation to the use of arthroscopy in the treatment of disorders of the hip. Cite this article: Bone Joint J 2013;95-B:10–19.
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Affiliation(s)
- A. Bedi
- University of Michigan, MedSport, Department
of Orthopaedic Surgery, Lobby A, 24
Frank Lloyd Wright Drive, Ann Arbor, Michigan
48106, USA
| | - B. T. Kelly
- Hospital for Special Surgery, 535
East 70th Street, New York, New York
10021, USA
| | - V. Khanduja
- Addenbrooke’s – Cambridge University Hospitals
NHS Foundation Trust, Box 37, Hills
Road, Cambridge CB2 0QQ, UK
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16
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Tanaka M, Vyas D, Moloney G, Bedi A, Pearle AD, Musahl V. What does it take to have a high-grade pivot shift? Knee Surg Sports Traumatol Arthrosc 2012; 20:737-42. [PMID: 22222616 DOI: 10.1007/s00167-011-1866-5] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 12/23/2011] [Indexed: 01/13/2023]
Abstract
UNLABELLED The pivot shift is the most specific clinical test to assess pathological knee joint rotatory laxity following ACL injury. This article attempts to describe the anatomic structures responsible for creating a high-grade pivot shift and their potential role in customizing ACL reconstruction. A review of the literature demonstrates that disruption of the secondary stabilizers of anterior translation of the lateral compartment including the lateral meniscus, anterolateral capsule, and IT band contributes to a high-grade pivot shift in the ACL-deficient knee. The morphology of the lateral tibial plateau, including increased posteroinferior tibial slope and small size, can also contribute to high-grade pivot shift. Factors that may decrease the grade of the pivot shift include medial compartment injury, MCL injury, patient guarding, and osteoarthritis. In conclusion, a high-grade pivot shift in the ACL-deficient knee is often associated with incompetence of the lateral soft tissue envelope. Rotatory laxity as assessed by the pivot shift may also be falsely underestimated by concomitant injuries. LEVEL OF EVIDENCE IV.
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Affiliation(s)
- M Tanaka
- Sports Medicine and Shoulder Service, Hospital for Special Surgery, New York, NY, USA
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17
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O'Gorman C, McMullan R, Webb CH, Bedi A. Trichosporon asahii. Blood-stream infection in a non-cancer patient receiving combination antifungal therapy. Ulster Med J 2006; 75:226-7. [PMID: 16964817 PMCID: PMC1891755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- C O'Gorman
- Department of Medical Microbiology, Kelvin Laboratories, Royal Victoria Hospital, Belfast, Northern Ireland, BT12 6BA. Ciaran.O'
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18
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Abstract
The recognition that the p53 tumour suppressor gene is frequently inactivated in human cancers has galvanized an intense pursuit of the fundamental mechanisms by which the encoded protein halts malignant transformation and tumour progression. It is now evident that p53 is a multifunctional transcription factor that is intimately involved in the cellular response to stressful stimuli such as DNA damage and hypoxia. In addition to its role in the surveillance mechanisms that arrest cell cycle progression, p53 can also trigger apoptosis in response to DNA damage or oncogenic aberrations that induce aberrant cell cycle progression. Since p53 is a critical component for DNA damage-induced apoptosis, the frequent occurrence of p53 mutations in human neoplasia provides a genetic basis for their poor response to genotoxic anticancer agents. Two recent studies offer key insights into the molecular mechanisms employed by p53 to induce cell death. One model indicates that p53 induces redox-related genes that generate reactive oxygen species and promote the oxidative degradation of mitochondrial components. The other demonstrates p53-mediated induction of DR5, a death receptor of the tumour necrosis factor receptor family, that induces death by caspase-mediated proteolysis. These insights provide an exhilarating array of possible therapeutic interventions against p53-deficient human cancers that may pay enormous dividends in the not-too-distant future.
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Affiliation(s)
- A Bedi
- Johns Hopkins Oncology Center, Division of Experimental Therapeutics & Pharmacology, 600 North Wolfe Street, Baltimore, MD 21287-8967, USA.
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19
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20
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21
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Bedi A, McBride WT, Armstrong MA, Murray JM, Fee JPH. Xenon has no effect on cytokine balance and adhesion molecule expression within an isolated cardiopulmonary bypass system. Br J Anaesth 2002; 89:546-50. [PMID: 12393353 DOI: 10.1093/bja/aef232] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Although almost inert chemically, xenon is not unreactive biologically. It interacts with receptors involved in the expression of cytokines and adhesion molecules. The effect of xenon on the immune function in whole blood has not been studied. METHODS We examined the effects of 70% xenon in oxygen on cytokine balance and expression of adhesion molecules in an isolated cardiopulmonary bypass (CPB) system, which simulates an evolving inflammatory response. Whole blood from 10 healthy male volunteers was circulated in a CBP system supplied with either 70% xenon in oxygen, or oxygen-enriched air - FO(2)=0.3 (control). We took samples of blood after 30, 60 and 90 min of simulated CBP. We measured interleukin (IL)-1beta, tumour necrosis factor (TNF)alpha, IL-8, IL-10, IL-1ra and TNF-sr-2 levels, and the expression of HLA-DR and the adhesion molecules L-selectin, CD18 and CD11b on monocytes, granulocytes and lymphocytes. RESULTS IL-8 concentrations were increased significantly, TNF-sr-2 concentrations decreased significantly and IL-10 levels decreased during bypass. There were no significant differences between the groups for any measured variable. CONCLUSION In an isolated CPB system, xenon and oxygen-enriched air had similar effects on cytokine production and expression of adhesion molecules.
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Affiliation(s)
- A Bedi
- Anaesthesia and Intensive Care Medicine, The Royal Group of Hospitals Trust, Grosvenor Road, Belfast BT12 6BA, N. Ireland, UK
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22
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Semenza GL, Artemov D, Bedi A, Bhujwalla Z, Chiles K, Feldser D, Laughner E, Ravi R, Simons J, Taghavi P, Zhong H. 'The metabolism of tumours': 70 years later. Novartis Found Symp 2002; 240:251-60; discussion 260-4. [PMID: 11727934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Otto Warburg's classic treatise on the reprogramming of tumour metabolism from oxidative to glycolytic metabolism was published in London in 1930. Although the Warburg effect is one of the most universal characteristics of solid tumours, the molecular basis for this phenomenon has only recently been elucidated by studies indicating that increased expression of genes encoding glucose transporters and glycolytic enzymes in tumour cells is mediated by the transcription factors c-MYC and HIF-1. Whereas c-myc is a direct target for oncogenic mutations, expression of hypoxia-inducible factor 1 (HIF-1) is indirectly up-regulated via gain-of-function mutations in oncogenes and loss-of-function mutations in tumour suppressor genes that result increased HIF-1alpha protein expression and/or increased HIF-1 transcriptional activity in a cell-type-specific manner. As a result of genetic alterations and intratumoral hypoxia, HIF-1alpha is overexpressed in the majority of common human cancers relative to the surrounding normal tissue. In human breast cancer and brain tumours, HIF-1alpha overexpression is strongly correlated with tumour grade and vascularity.
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Affiliation(s)
- G L Semenza
- Institute of Genetic Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
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23
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Abstract
This study reports the subjective, psychomotor and physiological properties of subanaesthetic concentrations of xenon. Ten healthy male volunteers received either xenon or nitrous oxide in a randomised crossover study design. The subjects breathed either xenon (Xe) or nitrous oxide (N2O) from a closed circuit breathing system, according to a randomised, double-blind protocol. The concentration of xenon required to produce sedation, ranged between 27 and 45% (median 35%). All subjects completed the xenon protocol. Subjects were tested using the Critical Flicker Fusion test and derived electroencephalogram parameters, however, neither test was found to reliably predict sedation. The respiratory rate decreased markedly during sedation with xenon. The subjects did not experience any airway irritability (coughing, breath-holding or laryngospasm) during administration of either gas. One subject required anti-emetic treatment in the N2O group compared to none in the Xe group. Eight subjects reported that they found sedation with xenon pleasant and preferable to nitrous oxide. Xenon sedation was well tolerated and was not associated with any adverse physiological effects, however, it was reported to be subjectively dissimilar to nitrous oxide.
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Affiliation(s)
- A Bedi
- The Department of Anaesthetics and Intensive Care Medicine, The Queen's University of Belfast, Northern Ireland.
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24
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Das MK, Cheriparambil K, Bedi A, Kassotis J, Reddy CV, Makan M, Dunbar CC, Saul B. Prolonged QRS duration (QRS >/=170 ms) and left axis deviation in the presence of left bundle branch block: A marker of poor left ventricular systolic function? Am Heart J 2001; 142:756-9. [PMID: 11685159 DOI: 10.1067/mhj.2001.118735] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Left bundle branch block (LBBB) is commonly associated with structural heart disease and left ventricular dysfunction. We propose that the QRS duration and degree of left-axis deviation (LAD) identify significant left ventricular systolic dysfunction in patients with LBBB. METHODS In this prospective study the ejection fraction (EF) of 300 consecutive patients with LBBB was evaluated by echocardiography. The relationship between QRS duration and LAD (axis between -30 degrees and -90 degrees ) and EF were derived. RESULTS There was no significant difference in age, sex, presence of ischemic or nonischemic cardiomyopathy and valvular heart disease, and EF among the patients with or without LAD. The EF of patients with QRS >/=170 milliseconds with LAD (n = 20) and without LAD (n = 18) was 25% +/- 16% and 23% +/- 13%, respectively (P =.71). The mean EF (24% +/- 10%) of the patients with a QRS duration of >/=170 milliseconds (n = 38) was significantly lower than the mean EF (36% +/- 16%) of the patients with a QRS duration of <170 milliseconds (n = 262, P <.015). The QRS duration also had a significant (P <.001) inverse correlation with EF (R = 0.37, adjusted R (2) = 0.13, SE of estimate = 16.21). However, the QRS axis was not significantly correlated with EF and did not have added predictive value. CONCLUSIONS The QRS duration has a significant inverse relationship with EF and prolongation of QRS duration (>/=170 milliseconds) in the presence of LBBB is a marker of significant left ventricular systolic dysfunction. The presence of LAD in LBBB does not signify a further decrease in EF.
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Affiliation(s)
- M K Das
- New York Presbyterian Hospital-Cornell University Medical College, New York, NY 10021, USA.
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25
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Singh G, Dhawan R, Potteiger CE, Bedi A, Modesto TA, Gutknecht DR. Acute renal infarction secondary to left ventricular thrombus, masquerading as a renal calculus--a case report and brief review of literature. Angiology 2001; 52:717-20. [PMID: 11666137 DOI: 10.1177/000331970105201009] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Acute embolic renal infarction is an entity that is often misdiagnosed as a renal calculus because of similar presenting symptoms. This leads to delay in the initiation of treatment and to increased morbidity. Few case reports exist relating cardiac emboli to acute renal infarction. The authors present a patient with a renal embolism secondary to left ventricular thrombus. A brief review of the literature highlighting the importance of clinical suspicion in making an accurate diagnosis, the utility of various diagnostic studies, and comparison of various treatment options is presented.
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Affiliation(s)
- G Singh
- Department of Internal Medicine, Geisinger Medical Center, Danville, PA, USA
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26
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Abstract
Sevoflurane and desflurane have important advantages over isoflurane and halothane. Disadvantages, which the clinician should keep in mind, include the degradation of both agents by soda lime under certain circumstances during closed circuit anaesthesia. As a result compound A and carbon monoxide (CO) may be generated in soda lime canisters and may be inhaled by patients. The extent to which this constitutes a significant problem during routine anaesthesia in humans is not clear. Recent developments in absorbent technology have the potential to reduce any hazard to negligible proportions. Other undesirable properties of the newer inhalation agents include agitation with sevoflurane in children and cardiovascular and airway effects with desflurane.
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Affiliation(s)
- A Bedi
- Department of Anaesthetics and Intensive Care Medicine, The Queen's University of Belfast, Belfast, UK.
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27
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Abstract
We report the in vitro longevity of a conventional soda lime carbon dioxide absorbent and an absorbent free from strong alkali (Amsorb). Although the times taken to breakthrough of carbon dioxide (> 0.5%) within an in vitro low flow breathing system were shorter with the alkali-free absorbent, we found that the size and shape of the absorbent container was the major factor in determining the efficiency of the carbon dioxide absorbents.
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Affiliation(s)
- A Bedi
- Department of Anaesthetics and Intensive Care Medicine, The Queen's University of Belfast, Whitla Medical Building, 97 Lisburn Road, Belfast BT9 6HP, UK.
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28
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Niu G, Shain KH, Huang M, Ravi R, Bedi A, Dalton WS, Jove R, Yu H. Overexpression of a dominant-negative signal transducer and activator of transcription 3 variant in tumor cells leads to production of soluble factors that induce apoptosis and cell cycle arrest. Cancer Res 2001; 61:3276-80. [PMID: 11309279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Gene therapy of B16 tumors with a dominant-negative signal transducer and activator of transcription (Stat3) variant, designated Stat3beta, results in inhibition of tumor growth and tumor regression. Although only 10-15% of the tumor cells are transfected in vivo, the Stat3beta-induced antitumor effect is associated with massive apoptosis of B16 tumor cells, indicative of a potent bystander effect. Here, we provide evidence that blocking Stat3 signaling in B16 cells results in release of soluble factors that are capable of inducing apoptosis and cell cycle arrest of nontransfected B16 cells. RNase protection assays using multi-template probes specific for key physiological regulators of apoptosis reveal that overexpression of Stat3beta in B16 tumor cells induces the expression of the apoptotic effector, tumor necrosis factor-related apoptosis-inducing ligand. These in vitro results suggest that the observed in vivo bystander effect leading to tumor cell growth inhibition is mediated, at least in part, by soluble factors produced as a result of overexpression of Stat3beta in tumor cells.
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Affiliation(s)
- G Niu
- Immunology Program, H. Lee Moffitt Cancer Center and Research Institute, 12902 Magnolia Drive, Tampa, Florida 33613, USA
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29
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Ravi R, Bedi GC, Engstrom LW, Zeng Q, Mookerjee B, Gélinas C, Fuchs EJ, Bedi A. Regulation of death receptor expression and TRAIL/Apo2L-induced apoptosis by NF-kappaB. Nat Cell Biol 2001; 3:409-16. [PMID: 11283615 DOI: 10.1038/35070096] [Citation(s) in RCA: 258] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
TRAIL (tumour-necrosis factor-related apoptosis ligand or Apo2L) triggers apoptosis through engagement of the death receptors TRAIL-R1 (also known as DR4) and TRAIL-R2 (DR5). Here we show that the c-Rel subunit of the transcription factor NF-kappaB induces expression of TRAIL-R1 and TRAIL-R2; conversely, a transdominant mutant of the inhibitory protein IkappaBalpha or a transactivation-deficient mutant of c-Rel reduces expression of either death receptor. Whereas NF-kappaB promotes death receptor expression, cytokine-mediated activation of the RelA subunit of NF-kappaB also increases expression of the apoptosis inhibitor, Bcl-xL, and protects cells from TRAIL. Inhibition of NF-kappaB by blocking activation of the IkappaB kinase complex reduces Bcl-x L expression and sensitizes tumour cells to TRAIL-induced apoptosis. The ability to induce death receptors or Bcl-xL may explain the dual roles of NF-kappaB as a mediator or inhibitor of cell death during immune and stress responses.
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Affiliation(s)
- R Ravi
- Johns Hopkins Oncology Center, The Johns Hopkins University School of Medicine, Bunting-Blaustein Cancer Research Building, 1650 Orleans Street, Baltimore, Maryland 21231, USA
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31
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Ravi R, Mookerjee B, Bhujwalla ZM, Sutter CH, Artemov D, Zeng Q, Dillehay LE, Madan A, Semenza GL, Bedi A. Regulation of tumor angiogenesis by p53-induced degradation of hypoxia-inducible factor 1alpha. Genes Dev 2000; 14:34-44. [PMID: 10640274 PMCID: PMC316350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
The switch to an angiogenic phenotype is a fundamental determinant of neoplastic growth and tumor progression. We demonstrate that homozygous deletion of the p53 tumor suppressor gene via homologous recombination in a human cancer cell line promotes the neovascularization and growth of tumor xenografts in nude mice. We find that p53 promotes Mdm2-mediated ubiquitination and proteasomal degradation of the HIF-1alpha subunit of hypoxia-inducible factor 1 (HIF-1), a heterodimeric transcription factor that regulates cellular energy metabolism and angiogenesis in response to oxygen deprivation. Loss of p53 in tumor cells enhances HIF-1alpha levels and augments HIF-1-dependent transcriptional activation of the vascular endothelial growth factor (VEGF) gene in response to hypoxia. Forced expression of HIF-1alpha in p53-expressing tumor cells increases hypoxia-induced VEGF expression and augments neovascularization and growth of tumor xenografts. These results indicate that amplification of normal HIF-1-dependent responses to hypoxia via loss of p53 function contributes to the angiogenic switch during tumorigenesis.
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Affiliation(s)
- R Ravi
- Johns Hopkins Oncology Center, Departments of Pediatrics and Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287 USA
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32
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Gladstone DE, Bedi A, Miller CB, Noga SJ, Griffin CA, Piantadosi S, Cagnoni PJ, Brodsky RA, Smith BD, Douglas TT, Shpall EJ, Jones RJ. Philadelphia chromosome-negative engraftment after autologous transplantation with granulocyte-macrophage colony-stimulating factor for chronic myeloid leukemia. Biol Blood Marrow Transplant 1999; 5:394-9. [PMID: 10595817 DOI: 10.1016/s1083-8791(99)70016-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Autologous bone marrow transplantation (BMT) has not been curative in chronic myeloid leukemia (CML), because of the inability to purge CML from the autograft and the absence of the allogeneic T cell-mediated antileukemic activity. However, recent advances demonstrate that normal progenitors can be selected from CML marrows by a variety of techniques, including isolation by their small size. Furthermore, we found that myeloid growth factors have a potent antileukemic effect against CML progenitors in vitro by inducing their terminal differentiation. Based on these data, we initiated a trial of autologous BMT in patients with high-risk CML. Autografts were processed in an attempt to enrich for normal progenitors, first by isolating small cells by counterflow centrifugal elutriation and then incubating them in granulocyte-macrophage colony-stimulating factor (GM-CSF) for 72 hours. After a conditioning regimen of busulfan and cyclophosphamide, all patients received GM-CSF daily for 2 months. The median age of the 13 patients in the trial was 45 years (range 17-56 years). The median duration of disease before BMT was 24 months (range 13-72 months). Eight patients were in chronic phase (CP), and five were in accelerated phase (AP). All patients failed to achieve a cytogenetic response to interferon-alpha and were 100% Philadelphia chromosome (Ph)+ before BMT. There were three transplant-related deaths, all AP patients. All of the remaining 10 patients engrafted with some degree of Ph- hematopoiesis; despite high-risk features, nine patients engrafted 100% Ph-. All patients relapsed cytogenetically at a median of 6 months (range 4-22 months). These results demonstrate that autologous BMT can consistently induce complete Ph- engraftment in CP patients. GM-CSF appears to produce a clinical antileukemic effect against CML after autologous BMT.
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MESH Headings
- Adolescent
- Adult
- Bone Marrow Transplantation/methods
- Bone Marrow Transplantation/mortality
- Cell Separation/methods
- Female
- Granulocyte-Macrophage Colony-Stimulating Factor/therapeutic use
- Growth Substances/therapeutic use
- Humans
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/mortality
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/therapy
- Leukemia, Myeloid, Accelerated Phase/mortality
- Leukemia, Myeloid, Accelerated Phase/therapy
- Male
- Middle Aged
- Philadelphia Chromosome
- Recurrence
- Survival Rate
- Transplantation, Autologous
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Affiliation(s)
- D E Gladstone
- Johns Hopkins Oncology Center, Baltimore, Maryland 21287-8967, USA
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33
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Abstract
BACKGROUND This article describes a carbon dioxide absorbent for use in anesthesia. The absorbent consists of calcium hydroxide with a compatible humectant, namely, calcium chloride. The absorbent mixture does not contain sodium or potassium hydroxide but includes two setting agents (calcium sulphate and polyvinylpyrrolidine) to improve hardness and porosity. METHODS The resultant mixture was formulated and subjected to standardized tests for hardness, porosity, and carbon dioxide absorption. Additionally, the new absorbent was exposed in vitro to sevoflurane, desflurane, isoflurane, and enflurane to determine whether these anesthetics were degraded to either compound A or carbon monoxide. The performance data and inertness of the absorbent were compared with two currently available brands of soda lime: Intersorb (Intersurgical Ltd., Berkshire, United Kingdom) and Dragersorb (Drager, Lubeck, Germany). RESULTS The new carbon dioxide absorbent conformed to United States Pharmacopeia specifications in terms of carbon dioxide absorption, granule hardness, and porosity. When the new material was exposed to sevoflurane (2%) in oxygen at a flow rate of 1 l/min, concentrations of compound A did not increase above those found in the parent drug (1.3-3.3 ppm). In the same experiment, mean +/-SD concentrations of compound A (32.5 +/- 4.5 ppm) were observed when both traditional brands of soda lime were used. After dehydration of the traditional soda limes, immediate exposure to desflurane (60%), enflurane (2%), and isoflurane (2%) produced concentrations of carbon monoxide of 600.0 +/- 10.0 ppm, 580.0 +/- 9.8 ppm, and 620.0 +/-10.1 ppm, respectively. In contrast, concentrations of carbon monoxide were negligible (1-3 ppm) when the anhydrous new absorbent was exposed to the same anesthetics. CONCLUSIONS The new material is an effective carbon dioxide absorbent and is chemically unreactive with sevoflurane, enflurane, isoflurane, and desflurane.
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Affiliation(s)
- J M Murray
- Department of Anaesthetics and Intensive Care Medicine and the School of Pharmacy, The Queen's University of Belfast, Northern Ireland.
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34
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Harris GJ, Codori AM, Lewis RF, Schmidt E, Bedi A, Brandt J. Reduced basal ganglia blood flow and volume in pre-symptomatic, gene-tested persons at-risk for Huntington's disease. Brain 1999; 122 ( Pt 9):1667-78. [PMID: 10468506 DOI: 10.1093/brain/122.9.1667] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The aim of this study was to examine basal ganglia volumes and regional cerebral blood flow in asymptomatic subjects at-risk for Huntington's disease who had undergone genetic testing. We determined which measures were the best 'markers' for the presence of the mutation and for the onset of symptoms. Twenty subjects who were Huntington's disease gene mutation-positive and 24 Huntington's disease gene mutation-negative participants, all of whom had a parent with genetically confirmed Huntington's disease, and were therefore 50% at-risk for inheriting the Huntington's disease gene mutation, were included in the study. To evaluate basal ganglia structure and function, MRI and single photon emission computed tomography (SPECT) were used. Quantitative measures of regional volumes and relative measures of regional perfusion were calculated. SPECT and MRI scans were co-registered so that MRI anatomy could be used accurately to place SPECT regions. Estimated years-to-onset in the mutation-positive subjects was calculated based on a regression formula that included gene (CAG)(n) repeat length and parental age of onset. Changes in imaging measures in relation to estimated years-to-onset were assessed. The imaging measure that was most affected in mutation-positive subjects was putamen volume. This was also the measure that correlated most strongly with approaching onset. In subjects >/=7 years from estimated onset age, the putamen volume measures were similar to those of the mutation-negative subjects. However, in subjects </=6 years from estimated onset age, there were dramatic reductions in putamen volume, resulting in >90% discrimination from both the far-from-onset and the mutation-negative subjects. Caudate volume and bicaudate ratio also showed a significant decline in the close-to-onset subjects, although to a lesser degree than putamen volume reductions. Furthermore, SPECT basal ganglia perfusion deficits were observed in mutation-positive subjects. Imaging markers of neuropathological decline preceding clinical onset are important for assessing the effects of treatments aimed at slowing the course of Huntington's disease. The current study suggests that quantitative assessment of basal ganglia may provide a means to track early signs of decline in individuals with the Huntington's disease gene mutation prior to clinical onset.
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Affiliation(s)
- G J Harris
- Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Boston, MA 02114, USA.
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35
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Abstract
A prospective, randomised, double-blinded study comparing three agents for peribulbar anaesthesia is reported. Sixty patients undergoing extracapsular cataract extraction under local anaesthesia were randomly allocated to receive peribulbar anaesthesia with lignocaine 2% with adrenaline; prilocaine 3% with felypressin 0.03 IU.ml-1 or 2% lignocaine and 0.5% bupivacaine in a ratio of 1:1, using a standardised two-injection technique. The pain of injection, time of onset of the block and the operating conditions at the start and finish of surgery were assessed. Peribulbar anaesthesia using lignocaine 2% was significantly more painful than the other solutions. The onset of anaesthesia adequate for surgery was similar in all three groups. Prilocaine 3% with felypressin was associated with the greatest number of blocks providing total akinesia of the eye. Inadequate duration of anaesthesia was seen in only one case; the solution used for this block was 2% lignocaine.
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Affiliation(s)
- A Bedi
- Department of Anaesthetics, Royal Group of Hospitals Trust, Belfast, UK
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36
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Ravi R, Mookerjee B, van Hensbergen Y, Bedi GC, Giordano A, El-Deiry WS, Fuchs EJ, Bedi A. p53-mediated repression of nuclear factor-kappaB RelA via the transcriptional integrator p300. Cancer Res 1998; 58:4531-6. [PMID: 9788595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The p53 tumor suppressor gene plays an instrumental role in transcriptional regulation of target genes involved in cellular stress responses. p53-dependent transactivation and transrepression require its interaction with p300/CBP, a coactivator that also interacts with the RelA subunit of nuclear factor-kappaB. We find that p53 inhibits RelA-dependent transactivation without altering RelA expression or inducible kappaB-DNA binding. p53-mediated repression of RelA is relieved by p300 overexpression and the increased RelA activity conferred by p53-deficiency is counteracted by either transactivation domain-deficient p300 fragments that bind RelA or a transdominant mutant of IkappaB alpha. Our results suggest that p53 can regulate diverse kappaB-dependent cellular responses.
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Affiliation(s)
- R Ravi
- Johns Hopkins Oncology Center, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-8967, USA
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37
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Ravi R, Bedi A, Fuchs EJ, Bedi A. CD95 (Fas)-induced caspase-mediated proteolysis of NF-kappaB. Cancer Res 1998; 58:882-6. [PMID: 9500443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Activation of the nuclear factor (NF)-kappaB transcription factor is instrumental for the immune response and the survival of peripheral activated T cells. We demonstrate that ligation of CD95 (Fas/APO1), a potent apoptotic stimulus in lymphocytes, results in repression of NF-kappaB activity in Jurkat T cells by inducing the proteolytic cleavage of NF-kappaB p65 (Rel A) and p50. Inhibition of caspase-3-related proteases by a specific acetylated aldehyde (Ac-DEVD-CHO) prevented CD95-induced cleavage of p65 (RelA) or p50 and restored the inducibility of NF-kappaB in cells treated with an antibody against CD95. The addition of recombinant caspase-3 also resulted in proteolytic cleavage of RelA p65 and p50 in vitro. TNF-alpha treatment, unlike CD95 ligation, did not result in the death of Jurkat cells but did so in the presence of I kappaB alphaM, a transdominant inhibitor of NF-kappaB. These results suggest that intact, functional NF-kappaB maintains the survival of activated T cells, and that CD95-induced cleavage of NF-kappaB subunits sensitizes T cells to apoptosis and, hence, facilitates the decay of an immune response.
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Affiliation(s)
- R Ravi
- Johns Hopkins Oncology Center, Division of Experimental Therapeutics and Pharmacology, Baltimore, Maryland 21287, USA
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38
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Abstract
Caspases are a family of cysteine proteases implicated in the biochemical and morphological changes that occur during apoptosis (programmed cell death). The loop domain of Bcl-2 is cleaved at Asp34 by caspase-3 (CPP32) in vitro, in cells overexpressing caspase-3, and after induction of apoptosis by Fas ligation and interleukin-3 withdrawal. The carboxyl-terminal Bcl-2 cleavage product triggered cell death and accelerated Sindbis virus-induced apoptosis, which was dependent on the BH3 homology and transmembrane domains of Bcl-2. Inhibitor studies indicated that cleavage of Bcl-2 may further activate downstream caspases and contribute to amplification of the caspase cascade. Cleavage-resistant mutants of Bcl-2 had increased protection from interleukin-3 withdrawal and Sindbis virus-induced apoptosis. Thus, cleavage of Bcl-2 by caspases may ensure the inevitability of cell death.
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Affiliation(s)
- E H Cheng
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, MD 21205, USA
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39
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Fuchs EJ, McKenna KA, Bedi A. p53-dependent DNA damage-induced apoptosis requires Fas/APO-1-independent activation of CPP32beta. Cancer Res 1997; 57:2550-4. [PMID: 9205051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In many cell types, the p53 tumor suppressor protein is required for the induction of apoptosis by DNA-damaging chemotherapy or radiation. Therefore, identification of the molecular determinants of p53-dependent cell death may aid in the design of effective therapies of p53-deficient cancers. We investigated whether p53-dependent apoptosis requires activation of CPP32beta (caspase 3), a cysteine protease that has been found to mediate apoptosis in response to ligation of the Fas molecule or to granzyme B, a component of CTL lytic granules. Irradiation-induced apoptosis was associated with p53-dependent activation of CPP32beta-related proteolysis, and normal thymocytes were protected from irradiation by Acetyl-Asp-Glu-Val-Asp-CHO (Ac-DEVD-CHO), a specific inhibitor of CPP32beta. We next examined whether the Fas system is required for p53-dependent apoptosis and whether stimuli that induce activation of CPP32beta induce apoptosis in p53-deficient cells. Thymocytes or activated T cells from Fas-deficient mice were resistant to apoptosis induced by ligation of Fas or CD3, respectively, but remained normally susceptible to irradiation. Thymocytes from p53-deficient mice, although resistant to DNA damage, remained sensitive to CPP32beta-mediated apoptosis induced by ligation of Fas or CD3, or by exposure to cytotoxic T cells. These results demonstrate that DNA damage-induced apoptosis of T cells requires p53-mediated activation of CPP32beta by a mechanism independent of Fas/FasL interactions and suggest that immunological or molecular methods of activating CPP32beta may be effective at inducing apoptosis in p53-deficient cancers that are resistant to conventional chemotherapy or irradiation.
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Affiliation(s)
- E J Fuchs
- Johns Hopkins Oncology Center, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
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40
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Yao SL, McKenna KA, Sharkis SJ, Bedi A. Requirement of p34cdc2 kinase for apoptosis mediated by the Fas/APO-1 receptor and interleukin 1beta-converting enzyme-related proteases. Cancer Res 1996; 56:4551-5. [PMID: 8840958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The induction of apoptosis by the Fas/APO-1 receptor is important for T-cell-mediated cytotoxicity and down-regulation of immune responses. Binding of Fas ligand to the Fas/APO-1 receptor transduces an apoptotic signal that requires activation of interleukin 1beta-converting enzyme (ICE) and CPP32beta, members of a family of cysteine proteases that are evolutionarily conserved determinants of cell death. We report here that Fas/APO-1-triggered apoptosis involves ICE-mediated activation of p34cdc2 kinase. Ligation of the Fas receptor resulted in the rapid stimulation of ICE proteolytic activity and activation of p34cdc2 kinase. Specific tetrapeptide inhibitors of ICE (Acetyl-Tyr-Val-Ala-Asp-chloromethylketone) or CPP32beta (Acetyl-Asp-Glu-Val-Asp-aldehyde) prevented the anti-Fas antibody-mediated activation of p34cdc2 and inhibited apoptosis. Inhibition of p34cdc2 activity by transient overexpression of a dominant-negative cdc2 construct or human WEE1 kinase inhibited Fas-mediated apoptosis. These results suggest that activation of p34cdc2 kinase is a critical determinant of cell death mediated by Fas and ICE family proteases.
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Affiliation(s)
- S L Yao
- The Johns Hopkins Oncology Center, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
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41
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Yao SL, Akhtar AJ, McKenna KA, Bedi GC, Sidransky D, Mabry M, Ravi R, Collector MI, Jones RJ, Sharkis SJ, Fuchs EJ, Bedi A. Selective radiosensitization of p53-deficient cells by caffeine-mediated activation of p34cdc2 kinase. Nat Med 1996; 2:1140-3. [PMID: 8837615 DOI: 10.1038/nm1096-1140] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The induction of tumor cell death by anticancer therapy results from a genetic program of autonomous cell death termed apoptosis. Because the p53 tumor suppressor gene is a critical component for induction of apoptosis in response to DNA damage, its inactivation in cancers may be responsible for their resistance to genotoxic anticancer agents. The cellular response to DNA damage involves a cell-cycle arrest at both the G1/S and G2/M transitions; these checkpoints maintain viability by preventing the replication or segregation of damaged DNA. The arrest at the G1 checkpoint is mediated by p53-dependent induction of p21WAF1/CIP1, whereas the G2 arrest involves inactivation of p34cdc2 kinase. Following DNA damage, p53-deficient cells fail to arrest at G1 and accumulate at the G2/M transition. We demonstrate that abrogation of G2 arrest by caffeine-mediated activation of p34cdc2 kinase results in the selective sensitization of p53-deficient primary and tumor cells to irradiation-induced apoptosis. These data suggest that pharmacologic activation of p34cdc2 kinase may be a useful therapeutic strategy for circumventing the resistance of p53-deficient cancers to genotoxic anticancer agents.
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Affiliation(s)
- S L Yao
- Johns Hopkins Oncology Center, Baltimore, Maryland 21287, USA
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42
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Brodsky RA, Bedi A, Jones RJ. Are growth factors leukemogenic? Leukemia 1996; 10:175-7. [PMID: 8558925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The National Cancer Institute (NCI) recently alerted clinicians to the possibility that patients, entered on a NCI-sponsored cooperative group trial of doxorubicin and cyclophosphamide adjuvant therapy for breast cancer, may be at high risk of developing secondary acute myeloid leukemia (AML). Secondary AML following standard doses of doxorubicin and cyclophosphamide is uncommon, suggesting that the high risk on this trial may result from its higher-than-standard doses of chemotherapy. However, the cases of secondary AML were characteristic of the type that follows treatment with topoisomerase II-active agents, especially etoposide, and this type of secondary AML is rare after treatment with either cyclophosphamide or doxorubicin at any dose. We raise the possibility that another component of this trial, hematopoietic growth factors to decrease the toxicities related to myelosuppression, may play an important role in the development of secondary AML. Growth factors not only stimulate hematopoietic progenitor proliferation and differentiation, they also regulate hematopoietic cell survival by interfering with apoptosis (programmed cell death). Inhibition of apoptosis by a variety of genetic factors is an important mechanism of oncogenesis, and appears to be the initiating event in some malignancies. Growth factor-mediated suppression of the apoptotic death of hematopoietic progenitors damaged by chemotherapy may contribute to their leukemic transformation.
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Affiliation(s)
- R A Brodsky
- Johns Hopkins Oncology Center, Johns Hopkins Medical Institutions, Baltimore, MD, USA
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43
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Pasricha PJ, Bedi A, O'Connor K, Rashid A, Akhtar AJ, Zahurak ML, Piantadosi S, Hamilton SR, Giardiello FM. The effects of sulindac on colorectal proliferation and apoptosis in familial adenomatous polyposis. Gastroenterology 1995; 109:994-8. [PMID: 7657130 DOI: 10.1016/0016-5085(95)90411-5] [Citation(s) in RCA: 147] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND & AIMS The mechanism by which sulindac causes regression of adenomas in patients with familial adenomatous polyposis (FAP) is unclear. Conflicting data on the drug's effects on colorectal epithelial proliferation have been reported. An alternative mechanism, and one not previously studied, is via induction of colorectal epithelial cell apoptosis (programmed cell death). This hypothesis was tested by studying the effects of sulindac on colorectal epithelial proliferation and apoptosis in patients with FAP. METHODS Cell proliferation was studied via immunohistochemistry for cell nuclear antigen in a group of 22 patients randomized to either sulindac (150 mg twice a day) or placebo in a previously published trial. The rectal epithelium from 7 additional patients with FAP treated with sulindac was examined by flow cytometry to assess changes in cell-cycle distribution and apoptosis. RESULTS Although sulindac caused a significant decrease in polyp size and number, there was no significant change in cytokinetic variables or cell cycle distribution 3 months after treatment. However, the subdiploid apoptotic fraction was increased significantly 3 months after treatment with sulindac (31.3% +/- 4.8% compared with 10% +/- 4.3% at baseline; P = 0.01). CONCLUSIONS Our findings suggest that sulindac does not affect colorectal epithelial proliferation and that its effects in patients with FAP may instead result from induction of apoptosis.
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Affiliation(s)
- P J Pasricha
- Department of Medicine, Johns Hopkins University School of Medicine and Hospital, Baltimore, Maryland, USA
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44
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Bedi A, Barber JP, Bedi GC, el-Deiry WS, Sidransky D, Vala MS, Akhtar AJ, Hilton J, Jones RJ. BCR-ABL-mediated inhibition of apoptosis with delay of G2/M transition after DNA damage: a mechanism of resistance to multiple anticancer agents. Blood 1995; 86:1148-58. [PMID: 7620167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
A critical determinant of the efficacy of antineoplastic therapy is the response of malignant cells to DNA damage induced by anticancer agents. The p53 tumor-suppressor gene is a critical component of two distinct cellular responses to DNA damage, the induction of a reversible arrest at the G1/S cell cycle checkpoint, and the activation of apoptosis, a genetic program of autonomous cell death. Expression of the BCR-ABL chimeric gene produced by a balanced translocation in chronic myeloid leukemia, confers resistance to multiple genotoxic anticancer agents. BCR-ABL expression inhibits the apoptotic response to DNA damage without altering either the p53-dependent WAF1/CIP1-mediated G1 arrest or DNA repair. BCR-ABL-mediated inhibition of DNA damage-induced apoptosis is associated with a prolongation of cell cycle arrest at the G2/M restriction point; the delay of G2/M transition may allow time to repair and complete DNA replication and chromosomal segregation, thereby preventing a mitotic catastrophe. The inherent resistance of human cancers to genotoxic agents may result not only by the loss or inactivation of the wild-type p53 gene, but also by genetic alterations such as BCR-ABL that can delay G2/M transition after DNA damage.
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MESH Headings
- Antineoplastic Agents/pharmacology
- Apoptosis
- Base Sequence
- Cell Cycle
- Chronic Disease
- DNA Damage
- DNA Nucleotidylexotransferase/metabolism
- DNA Repair
- Drug Resistance
- Fusion Proteins, bcr-abl/physiology
- Gene Expression Regulation, Neoplastic
- Humans
- In Vitro Techniques
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Molecular Sequence Data
- Oligonucleotides, Antisense/chemistry
- RNA, Messenger/genetics
- RNA, Neoplasm/genetics
- Radiation, Ionizing
- Tumor Cells, Cultured
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Affiliation(s)
- A Bedi
- Johns Hopkins Oncology Center, Baltimore, MD 21287, USA
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45
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Bedi A, Miller CB, Hanson JL, Goodman S, Ambinder RF, Charache P, Arthur RR, Jones RJ. Association of BK virus with failure of prophylaxis against hemorrhagic cystitis following bone marrow transplantation. J Clin Oncol 1995; 13:1103-9. [PMID: 7738616 DOI: 10.1200/jco.1995.13.5.1103] [Citation(s) in RCA: 192] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
PURPOSE Hemorrhagic cystitis (HC) after bone marrow transplantation (BMT) has been ascribed to cyclophosphamide metabolites. HC has also been associated with excretion of the BK type of polyomavirus. The relative contributions of cyclophosphamide metabolites and BK virus in the development of HC following BMT are unknown. PATIENTS AND METHODS We conducted a randomized trial to compare mesna with forced diuresis for prophylaxis against HC in 147 BMT recipients. We studied the association of BK virus with HC in 95 consecutive BMT recipients by prospectively monitoring urinary excretion of BK virus using polymerase chain reaction amplification of viral gene sequences. RESULTS HC occurred in 37 of 147 (25.2%) transplant recipients. The incidence of HC was similar in patients given mesna (26.8%, 19 of 71) or forced diuresis (23.7%, 18 of 76), and in recipients of allogeneic (27.2%, 18 of 64) or autologous marrow (22.9%, 19 of 83). The incidence of HC was unrelated to primary disease, preparative regimen, or occurrence of graft-versus-host disease (GVHD). Excretion of BK virus was demonstrated in 50 of 95 patients (52.6%); 38 patients (40%) had persistent BK viruria (> or = two consecutive positive samples). HC occurred in 19 of 38 patients (50%) with persistent BK viruria, in one of 12 (8.3%) with only a single urine sample positive for BK virus, and in none of 45 who did not excrete BK virus (P < .0001). Shedding of BK virus also had a strong temporal correlation with onset of HC (r = .95). CONCLUSION Mesna and forced diuresis are equally effective in abrogating the urothelial toxicity of preparative regimens for BMT. Since HC after BMT is virtually always associated with persistent BK viruria, strategies aimed at the prevention or elimination of viruria in BK seropositive recipients are warranted.
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Affiliation(s)
- A Bedi
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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46
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Bedi A, Pasricha PJ, Akhtar AJ, Barber JP, Bedi GC, Giardiello FM, Zehnbauer BA, Hamilton SR, Jones RJ. Inhibition of apoptosis during development of colorectal cancer. Cancer Res 1995; 55:1811-6. [PMID: 7728743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Colorectal tumorigenesis proceeds through an accumulation of specific genetic alterations. Studies of the mechanism by which these genetic changes effect malignant transformation have focused on the deregulation of cell proliferation. However, colorectal epithelial homeostasis is dependent not only on the rate of cell production but also on apoptosis, a genetically programmed process of autonomous cell death. We investigated whether colorectal tumorigenesis involved an altered susceptibility to apoptosis by examining colorectal epithelium from normal mucosa, adenomas from familial adenomatous polyposis, sporadic adenomas, and carcinomas. The transformation of colorectal epithelium to carcinomas was associated with a progressive inhibition of apoptosis. The inhibition of apoptosis in colorectal cancers may contribute to tumor growth, promote neoplastic progression, and confer resistance to cytotoxic anticancer agents.
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Affiliation(s)
- A Bedi
- Johns Hopkins Oncology Center, Baltimore, Maryland 21287, USA
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47
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Fuchs EJ, Bedi A, Jones RJ, Hess AD. Cytotoxic T cells overcome BCR-ABL-mediated resistance to apoptosis. Cancer Res 1995; 55:463-6. [PMID: 7834607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Chronic myeloid leukemia is a disease marked by expanded clonal hematopoiesis; it is incurable by chemotherapy or radiation but is cured in a majority of patients receiving bone marrow transplantation from nonidentical sibling donors, an outcome generally attributed to a T cell-mediated graft-versus-leukemia effect. In this report, we examine the effect of the P210BCR-ABL fusion protein of the BCR-ABL oncogene, the molecular hallmark of chronic myelogenous leukemia, on the sensitivity of mouse cell lines to apoptosis induced by chemotherapy, radiation, or activated cytotoxic T lymphocytes (CTLs). We find that, although cells expressing P210BCR-ABL by gene transfer are more resistant than their normal counterparts to apoptosis induced by chemotherapy or radiation, they are equally susceptible to apoptosis induced by alloreactive CTLs. These results show that CTLs overcome BCR-ABL-mediated resistance to apoptosis and, therefore, provide a biological correlation for the success of allogeneic bone marrow transplantation in chronic myelogenous leukemia.
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Affiliation(s)
- E J Fuchs
- Division of Bone Marrow Transplantation, Johns Hopkins Oncology Center, Baltimore, Maryland 21287-8985
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48
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Abstract
The hematopoietic developmental hierarchy originates with a rare population of lymphohematopoietic stem cells that are capable of extensive self-renewal as well as the continuous generation of more developmentally restricted progeny. The generation of mature blood cells from these pluripotent hematopoietic stem cells involves the highly regulated progression through successive stages involving commitment to a specific cell lineage, terminal differentiation of lineage-restricted progenitors, and growth arrest. Although the differentiation commitment of stem cells may be intrinsically determined, it is apparent that a wide variety of external and internal stimuli can influence and modulate lineage choice and differentiation. These factors cooperate with cellular transcription factors to activate or repress the expression of genes responsible for lineage choice, diverse mature phenotypes, and cell cycle progression. The extrinsic and genetic mechanisms that orchestrate the differentiation commitment and myeloid lineage restriction of pluripotent stem cells are of fundamental importance in the regulation of hematopoiesis. The elucidation of these mechanisms of normal myeloid differentiation has provided instrumental insights into the biology of leukemia and other hematopoietic disorders.
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Affiliation(s)
- A Bedi
- Johns Hopkins University, Baltimore, Maryland, USA
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49
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Bedi A, Griffin CA, Barber JP, Vala MS, Hawkins AL, Sharkis SJ, Zehnbauer BA, Jones RJ. Growth factor-mediated terminal differentiation of chronic myeloid leukemia. Cancer Res 1994; 54:5535-8. [PMID: 7923192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Expression of the BCR-ABL chimeric gene in chronic myeloid leukemia results in the inhibition of apoptosis, a genetically programmed process of autonomous cell death. BCR-ABL and other genetic factors that suppress apoptosis confer cross-resistance to cytotoxic agents with diverse mechanisms of action. Eradication of the chronic myeloid leukemia clone requires strategies that circumvent this inherent resistance to cytotoxic therapy. We have determined that BCR-ABL expression augments the sensitivity of hematopoietic cells to growth factor-mediated signals of differentiation; hematopoietic growth factors induce the selective terminal differentiation of chronic myeloid leukemia progenitors at concentrations that allow optimal growth of normal progenitors. Hematopoietic growth factors may be an effective strategy for the elimination of cytotoxic therapy-resistant leukemic cells by inducing their terminal differentiation while allowing concomitant expansion of coexistent normal hematopoietic progenitors.
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MESH Headings
- Animals
- Base Sequence
- Cell Differentiation/genetics
- Gene Expression Regulation, Leukemic/genetics
- Genes, abl/genetics
- Granulocytes/pathology
- Humans
- Interleukin-3/pharmacology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Macrophages/pathology
- Mice
- Molecular Sequence Data
- Oligonucleotides, Antisense/pharmacology
- Proto-Oncogenes/physiology
- Tumor Cells, Cultured
- Tumor Stem Cell Assay
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Affiliation(s)
- A Bedi
- Johns Hopkins Oncology Center, Baltimore, Maryland 21287-8967
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50
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Bedi A, Zehnbauer BA, Barber JP, Sharkis SJ, Jones RJ. Inhibition of apoptosis by BCR-ABL in chronic myeloid leukemia. Blood 1994; 83:2038-44. [PMID: 8161775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
BCR-ABL expression is presumed to effect clonal expansion in chronic myeloid leukemia (CML) by deregulation of cell proliferation. However, most studies have found that relative rates of cell proliferation are not increased in CML. Moreover, we found that CML progenitors display a normal proliferative response to growth factors and do not manifest greater proliferative potential than normal progenitors. Growth of malignancies depends on an imbalance between the rate of cell production and the rate of cell death. We found that BCR-ABL expression inappropriately prolongs the growth factor-independent survival of CML myeloid progenitors and granulocytes by inhibiting apoptosis, a genetically programmed process of active cell death; inhibition of BCR-ABL expression by antisense oligonucleotides reversed the suppression of apoptosis as well as the enhancement of survival. The decreased rate of programmed cell death appears to be the primary mechanism by which BCR-ABL effects expansion of the leukemic clone in CML.
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Affiliation(s)
- A Bedi
- Johns Hopkins Oncology Center, Johns Hopkins Medical Institutions, Baltimore, MD 21287-8967
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