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Murugan AK, Kannan S, Alzahrani AS. TERT promoter mutations in gliomas: Molecular roles in tumorigenesis, metastasis, diagnosis, prognosis, therapeutic targeting, and drug resistance. Biochim Biophys Acta Rev Cancer 2025; 1880:189243. [PMID: 39674418 DOI: 10.1016/j.bbcan.2024.189243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 12/06/2024] [Accepted: 12/08/2024] [Indexed: 12/16/2024]
Abstract
Telomerase reverse transcriptase (TERT), a critical player in cellular immortalization, has emerged as a focal point of investigation due to its frequent promoter mutations in various human malignancies. TERT promoter mutations exhibit a significant role in tumorigenesis, fostering unbridled cellular proliferation and survival. This comprehensive review delves into the landscape of TERT promoter mutations and their profound implications in cancer, particularly within the context of gliomas. This article meticulously examines the intricate interplay between TERT promoter mutations and the metastatic cascade, shedding light on their capacity to orchestrate invasive behavior in gliomas. Moreover, this review describes the recent trends in therapeutic targeting of the TERT and dissects the evolving landscape of drug resistance associated with TERT mutations, providing insights into potential therapeutic challenges. In addition, the diagnostic and prognostic implications of TERT promoter mutations in gliomas are scrutinized, unraveling their potential as robust biomarkers. It also discusses the recent advancements in molecular diagnostics, illustrating the promise of TERT mutations as diagnostic tools and prognostic indicators. This review collectively aims to contribute to a deeper understanding of TERT promoter mutations in gliomas, offering a foundation for future research endeavors and paving the way for innovative strategies in glioma management.
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Affiliation(s)
- Avaniyapuram Kannan Murugan
- Department of Molecular Oncology, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia.
| | - Siddarth Kannan
- School of Medicine, University of Central Lancashire, Preston PR1 2HE, UK
| | - Ali S Alzahrani
- Department of Molecular Oncology, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia; Department of Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
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2
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Palamarchuk AI, Kovalenko EI, Streltsova MA. Multiple Actions of Telomerase Reverse Transcriptase in Cell Death Regulation. Biomedicines 2023; 11:biomedicines11041091. [PMID: 37189709 DOI: 10.3390/biomedicines11041091] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/25/2023] [Accepted: 04/02/2023] [Indexed: 04/07/2023] Open
Abstract
Telomerase reverse transcriptase (TERT), a core part of telomerase, has been known for a long time only for its telomere lengthening function by reverse transcription of RNA template. Currently, TERT is considered as an intriguing link between multiple signaling pathways. The diverse intracellular localization of TERT corresponds to a wide range of functional activities. In addition to the canonical function of protecting chromosome ends, TERT by itself or as a part of the telomerase complex participates in cell stress responses, gene regulation and mitochondria functioning. Upregulation of TERT expression and increased telomerase activity in cancer and somatic cells relate to improved survival and persistence of such cells. In this review, we summarize the data for a comprehensive understanding of the role of TERT in cell death regulation, with a focus on the interaction of TERT with signaling pathways involved in cell survival and stress response.
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Affiliation(s)
- Anastasia I. Palamarchuk
- Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Elena I. Kovalenko
- Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Maria A. Streltsova
- Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
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da Mota THA, Camargo R, Biojone ER, Guimarães AFR, Pittella-Silva F, de Oliveira DM. The Relevance of Telomerase and Telomere-Associated Proteins in B-Acute Lymphoblastic Leukemia. Genes (Basel) 2023; 14:genes14030691. [PMID: 36980962 PMCID: PMC10048576 DOI: 10.3390/genes14030691] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/04/2023] [Accepted: 03/08/2023] [Indexed: 03/14/2023] Open
Abstract
Telomeres and telomerase are closely linked to uncontrolled cellular proliferation, immortalization and carcinogenesis. Telomerase has been largely studied in the context of cancer, including leukemias. Deregulation of human telomerase gene hTERT is a well-established step in leukemia development. B-acute lymphoblastic leukemia (B-ALL) recovery rates exceed 90% in children; however, the relapse rate is around 20% among treated patients, and 10% of these are still incurable. This review highlights the biological and clinical relevance of telomerase for B-ALL and the implications of its canonical and non-canonical action on signaling pathways in the context of disease and treatment. The physiological role of telomerase in lymphocytes makes the study of its biomarker potential a great challenge. Nevertheless, many works have demonstrated that high telomerase activity or hTERT expression, as well as short telomeres, correlate with poor prognosis in B-ALL. Telomerase and related proteins have been proven to be promising pharmacological targets. Likewise, combined therapy with telomerase inhibitors may turn out to be an alternative strategy for B-ALL.
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Affiliation(s)
- Tales Henrique Andrade da Mota
- Laboratory of Molecular Pathology of Cancer, University of Brasilia, Brasilia 70910-900, Brazil
- Laboratory of Molecular Analysis, Faculty of Ceilândia, University of Brasilia, Brasilia 72220-275, Brazil
- Correspondence:
| | - Ricardo Camargo
- Brasília Children’s Hospital José Alencar, Brasilia 70684-831, Brazil
| | | | - Ana Flávia Reis Guimarães
- Laboratory of Molecular Analysis, Faculty of Ceilândia, University of Brasilia, Brasilia 72220-275, Brazil
| | - Fabio Pittella-Silva
- Laboratory of Molecular Pathology of Cancer, University of Brasilia, Brasilia 70910-900, Brazil
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Sarvizadeh M, Hasanpour O, Naderi Ghale-Noie Z, Mollazadeh S, Rezaei M, Pourghadamyari H, Masoud Khooy M, Aschner M, Khan H, Rezaei N, Shojaie L, Mirzaei H. Allicin and Digestive System Cancers: From Chemical Structure to Its Therapeutic Opportunities. Front Oncol 2021; 11:650256. [PMID: 33987085 PMCID: PMC8111078 DOI: 10.3389/fonc.2021.650256] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 02/10/2021] [Indexed: 12/24/2022] Open
Abstract
Digestive system cancer tumors are one of the major causes of cancer-related fatalities; the vast majority of them are colorectal or gastric malignancies. Epidemiological evidence confirmed that allium-containing food, such as garlic, reduces the risk of developing malignancies. Among all compounds in garlic, allicin has been most researched, as it contains sulfur and produces many second degradation compounds, such as sulfur dioxide, diallyl sulfide (DAS), diallyl trisulfide (DATS), and diallyl disulfide (DADS) in the presence of enzymatic reactions in gastric juice. These substances have shown anti-inflammatory, antidiabetic, antihypertensive, antifungal, antiviral, antibacterial, and anticancer efficacy, including gastrointestinal (GI) cancers, leukemia, and skin cancers. Herein, we summarize the therapeutic potential of allicin in the treatment of GI cancers.
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Affiliation(s)
- Mahshad Sarvizadeh
- Nutrition and Endocrine Research Centre, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Omid Hasanpour
- School of Paramedicine, Kashan University of Medical Sciences, Kashan, Iran
| | | | - Samaneh Mollazadeh
- Natural Products and Medicinal Plants Research Center, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Mohammad Rezaei
- Department of Diabetes, Obesity and Metabolism, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Hossein Pourghadamyari
- Department of Clinical Biochemistry, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | | | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Haroon Khan
- Department of Pharmacy, Abdul Wali Khan University, Mardan, Pakistan
| | - Nima Rezaei
- Department of Medical Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
- Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Layla Shojaie
- Department of Medicine, Research Center for Liver Diseases, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Hamed Mirzaei
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Institute for Basic Sciences, Kashan University of Medical Sciences, Kashan, Iran
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Thompson CA, Wong JM. Non-canonical Functions of Telomerase Reverse Transcriptase: Emerging Roles and Biological Relevance. Curr Top Med Chem 2020; 20:498-507. [DOI: 10.2174/1568026620666200131125110] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/10/2020] [Accepted: 01/21/2020] [Indexed: 12/11/2022]
Abstract
Increasing evidence from research on telomerase suggests that in addition to its catalytic telomere
repeat synthesis activity, telomerase may have other biologically important functions. The canonical
roles of telomerase are at the telomere ends where they elongate telomeres and maintain genomic
stability and cellular lifespan. The catalytic protein component Telomerase Reverse Transcriptase
(TERT) is preferentially expressed at high levels in cancer cells despite the existence of an alternative
mechanism for telomere maintenance (alternative lengthening of telomeres or ALT). TERT is also expressed
at higher levels than necessary for maintaining functional telomere length, suggesting other possible
adaptive functions. Emerging non-canonical roles of TERT include regulation of non-telomeric
DNA damage responses, promotion of cell growth and proliferation, acceleration of cell cycle kinetics,
and control of mitochondrial integrity following oxidative stress. Non-canonical activities of TERT primarily
show cellular protective effects, and nuclear TERT has been shown to protect against cell death
following double-stranded DNA damage, independent of its role in telomere length maintenance. TERT
has been suggested to act as a chromatin modulator and participate in the transcriptional regulation of
gene expression. TERT has also been reported to regulate transcript levels through an RNA-dependent
RNA Polymerase (RdRP) activity and produce siRNAs in a Dicer-dependent manner. At the mitochondria,
TERT is suggested to protect against oxidative stress-induced mtDNA damage and promote mitochondrial
integrity. These extra-telomeric functions of TERT may be advantageous in the context of increased
proliferation and metabolic stress often found in rapidly-dividing cancer cells. Understanding
the spectrum of non-canonical functions of telomerase may have important implications for the rational
design of anti-cancer chemotherapeutic drugs.
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Affiliation(s)
- Connor A.H. Thompson
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, V6T 1Z3, Canada
| | - Judy M.Y. Wong
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, V6T 1Z3, Canada
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Gu B, Wang J, Song Y, Wang Q, Wu Q. The inhibitory effects of ginsenoside Rd on the human glioma U251 cells and its underlying mechanisms. J Cell Biochem 2018; 120:4444-4450. [PMID: 30260020 DOI: 10.1002/jcb.27732] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 08/30/2018] [Indexed: 01/26/2023]
Abstract
OBJECTIVE The current study was designed to investigate the inhibitory effects of ginsenoside Rd (Gs-Rd) on human glioma U251 cells in vitro and its possible underlying mechanisms. METHODS The groups included blank control group, low concentration Gs-Rd treatment group (20 μM), mid concentration Gs-Rd treatment group (40 μM), and high concentration Gs-Rd treatment group (80 μM). The proliferative activity of human glioma U251 cells was detected by the MTT assay. Flow cytometry was performed to measure cell apoptosis of human glioma U251 cells. In addition, the ELISA assay was used to measure the telomerase activities in different groups on 24 hours, 48 hours, and 72 hours. Furthermore, real-time quantitative polymerase chain reaction (RT-PCR) and Western blot analysis were performed to measure the expression of Bcl-2, human telomerase catalytic subunit (hTERT), and caspase-3 in different groups on 48 hours at both messenger RNA (mRNA) and protein levels. RESULTS The proliferation of U251 cells was inhibited by Gs-Rd with different concentrations in the dose- and time-dependent manners. In addition, Gs-Rd promoted U251 cell apoptosis rate in a dose-dependent manner. Gs-Rd with different concentrations (20 μM, 40 μM, and 80 μM) significantly enhanced the expression of teleomerase on 24 hours and 48 hours. In addition, Gs-Rd with different concentrations significantly increased caspase-3 and decreased Bcl-2 and hTERT expressions at both mRNA and protein levels. CONCLUSION The Gs-Rd can remarkably inhibit the proliferation and promote cell apoptosis of human glioma U251 cells. The possible underlying mechanisms could be related to inhibiting telomerase activity, downregulating expression of Bcl-2 and hTERT, and upregulating expression of caspase-3 of human glioma U251 cells.
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Affiliation(s)
- Biao Gu
- Department of Thoracic Surgery, The Affiliated Huai'an No.1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu, China
| | - Jipeng Wang
- Department of Respiratory Medicine, The Affiliated Huaian No.1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu, China
| | - Yaqi Song
- Department of Radiation Oncology, The Affiliated Huaian No.1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu, China
| | - Qi Wang
- Department of Thoracic Surgery, The Affiliated Huai'an No.1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu, China
| | - Qingquan Wu
- Department of Thoracic Surgery, The Affiliated Huai'an No.1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu, China
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Jin Y, You L, Kim HJ, Lee HW. Telomerase Reverse Transcriptase Contains a BH3-Like Motif and Interacts with BCL-2 Family Members. Mol Cells 2018; 41:684-694. [PMID: 29937479 PMCID: PMC6078858 DOI: 10.14348/molcells.2018.0206] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Accepted: 05/21/2018] [Indexed: 12/12/2022] Open
Abstract
Upregulation of human telomerase reverse transcriptase (hTERT) expression is an important factor in the cellular survival and cancer. Although growing evidence suggests that hTERT inhibits cellular apoptosis by telomere-independent functions, the mechanisms involved are not fully understood. Here, we show that hTERT contains a BH3-like motif, a short peptide sequence found in BCL-2 family proteins, and interacts with anti-apoptotic BCL-2 family proteins MCL-1 and BCL-xL, suggesting a functional link between hTERT and the mitochondrial pathway of apoptosis. Additionally, we propose that hTERT can be categorized into the atypical BH3-only proteins that promote cellular survival, possibly due to the non-canonical interaction between hTERT and antiapoptotic proteins. Although the detailed mechanisms underlying the hTERT BH3-like motif functions and interactions between hTERT and BCL-2 family proteins have not been elucidated, this work proposes a possible connection between hTERT and BCL-2 family members and reconsiders the role of the BH3-like motif as an interaction motif.
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Affiliation(s)
- Young Jin
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722,
Korea
| | - Long You
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722,
Korea
| | - Hye Jeong Kim
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722,
Korea
| | - Han-Woong Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722,
Korea
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Genetic and epigenetic background and protein expression profiles in relation to telomerase activation in medullary thyroid carcinoma. Oncotarget 2018; 7:21332-46. [PMID: 26870890 PMCID: PMC5008288 DOI: 10.18632/oncotarget.7237] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 01/17/2016] [Indexed: 01/08/2023] Open
Abstract
Medullary thyroid carcinomas (MTCs) exhibit telomerase activation in strong association with shorter patient survival. To understand the background of telomerase activation we quantified TERT copy numbers and TERT promoter methylation in 42 MTCs and normal thyroid references. Gain of TERT was demonstrated by quantitative PCR in 5/39 sporadic MTC. Increased methylation index (MetI) for CpG methylation at the TERT promoter was found in sporadic MTCs (P < 0.0001) and in MEN 2 associated MTCs (P = 0.011) vs. normal thyroid tissues. MetI correlated positively with TERT gene expression (r = 0.432, P = 0.006) and negatively with telomere length (r = −0.343, P = 0.032). MTC cases with MetI above the median of 52% had shorter survival as compared to cases with lower MetI (P = 0.005 for overall survival and P = 0.007 for disease-related survival). Protein expression profiles obtained by mass spectrometry were then studied in relation to telomerase activation in MTCs. Comparing protein levels between tumors defined by telomerase activity status, 240 proteins were associated with telomerase activity. Among telomerase activation positive cases a set of proteins was found to discriminate between MTCs with high and low TERT gene expression with enrichment for proteins involved in telomerase regulation. XRCC5 mRNA expression was found increased in MTCs vs. normal thyroid (P = 0.007). In conclusion the findings suggest a role for TERT copy number gain, TERT promoter methylation and XRCC5 expression in telomerase activation and telomere maintenance of MTC.
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Telomerase reverse transcriptase promotes chemoresistance by suppressing cisplatin-dependent apoptosis in osteosarcoma cells. Sci Rep 2017; 7:7070. [PMID: 28765565 PMCID: PMC5539325 DOI: 10.1038/s41598-017-07204-w] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 06/23/2017] [Indexed: 11/18/2022] Open
Abstract
Cisplatin is one of the most efficacious antimitotic drugs used in the treatment of a range of malignant tumors. However, treatment failures are common due to the development of chemoresistance. In addition to its telomere maintenance function, telomerase plays a pro-survival role, inducing decreased apoptosis and increased resistance against DNA damage. Elucidation of the molecular mechanisms underlying this effect is critical to improve treatment outcomes. Previously, our group showed higher telomerase reverse transcriptase(TERT) expression in cisplatin resistant osteosarcoma cells. In this study, confocal fluorescence microscopy experiments revealed that TERT translocates from the nucleus to mitochondria in cisplatin treated osteosarcoma cells. We observed decreased apoptosis rate and improved mitochondrial function in TERT-overexpressing cells following cisplatin treatment. Based on these results, we further established that TERT inhibits cisplatin-induced apoptosis independently of telomerase reverse transcriptase activity. Moreover, TERT suppressed cisplatin-induced apoptosis and improved mitochondrial function via alleviating intracellular ROS in osteosarcoma cells. Our finding that TERT shuttles from the nucleus to the mitochondrion in response to cisplatin treatment and inhibits cisplatin-induced apoptosis in osteosarcoma cells may be especially important to overcome drug resistance.
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G-Quadruplex surveillance in BCL-2 gene: a promising therapeutic intervention in cancer treatment. Drug Discov Today 2017; 22:1165-1186. [PMID: 28506718 DOI: 10.1016/j.drudis.2017.05.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 03/20/2017] [Accepted: 05/05/2017] [Indexed: 02/07/2023]
Abstract
Recently, therapeutic implications of BCL-2 quadruplex invigorated the field of clinical oncology. This Keynote review discusses how a BCL-2 quadruplex-selective approach circumvents the limitations of existing therapeutics; and which improvisations might ameliorate the recent trends of quadruplex-based treatment.
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New surprises from an old favourite: The emergence of telomerase as a key player in the regulation of cancer stemness. Biochimie 2016; 121:170-8. [DOI: 10.1016/j.biochi.2015.12.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 12/09/2015] [Indexed: 12/30/2022]
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Mohammad RM, Muqbil I, Lowe L, Yedjou C, Hsu HY, Lin LT, Siegelin MD, Fimognari C, Kumar NB, Dou QP, Yang H, Samadi AK, Russo GL, Spagnuolo C, Ray SK, Chakrabarti M, Morre JD, Coley HM, Honoki K, Fujii H, Georgakilas AG, Amedei A, Niccolai E, Amin A, Ashraf SS, Helferich WG, Yang X, Boosani CS, Guha G, Bhakta D, Ciriolo MR, Aquilano K, Chen S, Mohammed SI, Keith WN, Bilsland A, Halicka D, Nowsheen S, Azmi AS. Broad targeting of resistance to apoptosis in cancer. Semin Cancer Biol 2015; 35 Suppl:S78-S103. [PMID: 25936818 PMCID: PMC4720504 DOI: 10.1016/j.semcancer.2015.03.001] [Citation(s) in RCA: 605] [Impact Index Per Article: 60.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 03/04/2015] [Accepted: 03/04/2015] [Indexed: 12/15/2022]
Abstract
Apoptosis or programmed cell death is natural way of removing aged cells from the body. Most of the anti-cancer therapies trigger apoptosis induction and related cell death networks to eliminate malignant cells. However, in cancer, de-regulated apoptotic signaling, particularly the activation of an anti-apoptotic systems, allows cancer cells to escape this program leading to uncontrolled proliferation resulting in tumor survival, therapeutic resistance and recurrence of cancer. This resistance is a complicated phenomenon that emanates from the interactions of various molecules and signaling pathways. In this comprehensive review we discuss the various factors contributing to apoptosis resistance in cancers. The key resistance targets that are discussed include (1) Bcl-2 and Mcl-1 proteins; (2) autophagy processes; (3) necrosis and necroptosis; (4) heat shock protein signaling; (5) the proteasome pathway; (6) epigenetic mechanisms; and (7) aberrant nuclear export signaling. The shortcomings of current therapeutic modalities are highlighted and a broad spectrum strategy using approaches including (a) gossypol; (b) epigallocatechin-3-gallate; (c) UMI-77 (d) triptolide and (e) selinexor that can be used to overcome cell death resistance is presented. This review provides a roadmap for the design of successful anti-cancer strategies that overcome resistance to apoptosis for better therapeutic outcome in patients with cancer.
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Affiliation(s)
- Ramzi M Mohammad
- Department of Oncology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, United States; Interim translational Research Institute, Hamad Medical Corporation, Doha, Qatar.
| | - Irfana Muqbil
- Department of Oncology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, United States
| | - Leroy Lowe
- Getting to Know Cancer, Truro, Nova Scotia, Canada
| | - Clement Yedjou
- C-SET, [Jackson, #229] State University, Jackson, MS, United States
| | - Hsue-Yin Hsu
- Department of Life Sciences, Tzu-Chi University, Hualien, Taiwan
| | - Liang-Tzung Lin
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Markus David Siegelin
- Department of Pathology and Cell Biology, Columbia University, New York City, NY, United States
| | - Carmela Fimognari
- Dipartimento di Scienze per la Qualità della Vita Alma Mater Studiorum-Università di Bologna, Italy
| | - Nagi B Kumar
- Moffit Cancer Center, University of South Florida College of Medicine, Tampa, FL, United States
| | - Q Ping Dou
- Department of Oncology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, United States; Departments of Pharmacology and Pathology, Karmanos Cancer Institute, Detroit MI, United States
| | - Huanjie Yang
- The School of Life Science and Technology, Harbin Institute of Technology, Harbin, Heilongjiang, China
| | | | - Gian Luigi Russo
- Institute of Food Sciences National Research Council, Avellino, Italy
| | - Carmela Spagnuolo
- Institute of Food Sciences National Research Council, Avellino, Italy
| | - Swapan K Ray
- Department of Pathology, Microbiology, and Immunology, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Mrinmay Chakrabarti
- Department of Pathology, Microbiology, and Immunology, University of South Carolina School of Medicine, Columbia, SC, United States
| | - James D Morre
- Mor-NuCo, Inc, Purdue Research Park, West Lafayette, IN, United States
| | - Helen M Coley
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, United Kingdom
| | - Kanya Honoki
- Department of Orthopedic Surgery, Nara Medical University, Kashihara, Japan
| | - Hiromasa Fujii
- Department of Orthopedic Surgery, Nara Medical University, Kashihara, Japan
| | - Alexandros G Georgakilas
- Department of Physics, School of Applied Mathematical and Physical Sciences, National Technical University of Athens, Zografou 15780, Athens, Greece
| | - Amedeo Amedei
- Department of Experimental and Clinical Medicine, university of florence, Italy
| | - Elena Niccolai
- Department of Experimental and Clinical Medicine, university of florence, Italy
| | - Amr Amin
- Department of Biology, College of Science, UAE University, United Arab Emirates; Faculty of Science, Cairo University, Egypt
| | - S Salman Ashraf
- Department of Chemistry, College of Science, UAE University, United Arab Emirates
| | - William G Helferich
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Xujuan Yang
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Chandra S Boosani
- Department of BioMedical Sciences, School of Medicine Creighton University, Omaha NE, United States
| | - Gunjan Guha
- School of Chemical and Bio Technology, SASTRA University, Thanjavur, India
| | - Dipita Bhakta
- School of Chemical and Bio Technology, SASTRA University, Thanjavur, India
| | | | - Katia Aquilano
- Department of Biology, University of Rome "Tor Vergata", Italy
| | - Sophie Chen
- Ovarian and Prostate Cancer Research Trust Laboratory, Guildford, Surrey, United Kingdom
| | - Sulma I Mohammed
- Department of Comparative Pathobiology and Purdue University Center for Cancer Research, Purdue, West Lafayette, IN, United States
| | - W Nicol Keith
- Institute of Cancer Sciences, University of Glasgow, Glasgow, Ireland
| | - Alan Bilsland
- Institute of Cancer Sciences, University of Glasgow, Glasgow, Ireland
| | - Dorota Halicka
- Department of Pathology, New York Medical College, Valhalla, NY, United States
| | - Somaira Nowsheen
- Mayo Graduate School, Mayo Medical School, Mayo Clinic Medical Scientist Training Program, Rochester, MN, United States
| | - Asfar S Azmi
- Department of Oncology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, United States
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Narayanan KB, Ali M, Barclay BJ, Cheng Q(S, D’Abronzo L, Dornetshuber-Fleiss R, Ghosh PM, Gonzalez Guzman MJ, Lee TJ, Leung PS, Li L, Luanpitpong S, Ratovitski E, Rojanasakul Y, Romano MF, Romano S, Sinha RK, Yedjou C, Al-Mulla F, Al-Temaimi R, Amedei A, Brown DG, Ryan EP, Colacci AM, Hamid RA, Mondello C, Raju J, Salem HK, Woodrick J, Scovassi A, Singh N, Vaccari M, Roy R, Forte S, Memeo L, Kim SY, Bisson WH, Lowe L, Park HH. Disruptive environmental chemicals and cellular mechanisms that confer resistance to cell death. Carcinogenesis 2015; 36 Suppl 1:S89-S110. [PMID: 26106145 PMCID: PMC4565614 DOI: 10.1093/carcin/bgv032] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 01/28/2015] [Accepted: 02/03/2015] [Indexed: 12/12/2022] Open
Abstract
Cell death is a process of dying within biological cells that are ceasing to function. This process is essential in regulating organism development, tissue homeostasis, and to eliminate cells in the body that are irreparably damaged. In general, dysfunction in normal cellular death is tightly linked to cancer progression. Specifically, the up-regulation of pro-survival factors, including oncogenic factors and antiapoptotic signaling pathways, and the down-regulation of pro-apoptotic factors, including tumor suppressive factors, confers resistance to cell death in tumor cells, which supports the emergence of a fully immortalized cellular phenotype. This review considers the potential relevance of ubiquitous environmental chemical exposures that have been shown to disrupt key pathways and mechanisms associated with this sort of dysfunction. Specifically, bisphenol A, chlorothalonil, dibutyl phthalate, dichlorvos, lindane, linuron, methoxychlor and oxyfluorfen are discussed as prototypical chemical disruptors; as their effects relate to resistance to cell death, as constituents within environmental mixtures and as potential contributors to environmental carcinogenesis.
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Affiliation(s)
- Kannan Badri Narayanan
- Department of Chemistry and Biochemistry, Yeungnam University, Gyeongsan 712-749, South Korea
- Sultan Zainal Abidin University, Malaysia
- Plant Biotechnologies Inc, St. Albert AB, Canada
- Computer Science Department, Southern Illinois University, Carbondale, IL 62901, USA
- Department of Urology, University of California Davis, Sacramento, CA 95817, USA
- Department of Pharmacology and Toxicology, University of Vienna, Austria
- University of Puerto Rico, Medical Sciences Campus, School of Public Health, Nutrition Program, San Juan Puerto Rico 00936-5067, USA
- Department of Anatomy, College of Medicine, Yeungnam University, Daegu, 705-717, South Korea
- School of Biomedical Science, The Chinese University Of Hong Kong, Hong Kong, China
- Siriraj Center of Excellence for Stem Cell Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Department of Otolaryngology/Head and Neck Surgery, Head and Neck Cancer Research Division, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
- Department of Pharmaceutical Sciences, Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, WV 26506, USA
- Department of Molecular Medicine and Medical Biotechnology, Federico II University of Naples, 80131 Naples, Italy
- Department of Molecular and Experimental Medicine, MEM 180, The Scripps Research Institute, La Jolla, CA 92037, USA
- Department of Biology, Jackson State University, Jackson, MS 39217, USA
- Department of Pathology, Kuwait University, Safat 13110, Kuwait
- Department of Experimental and Clinical Medicine, University of Firenze, Firenze, 50134, Italy
- Department of Environmental and Radiological Health Sciences, Colorado state University/ Colorado School of Public Health, Fort Collins, CO 80523-1680, USA
- Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna, 40126, Italy
- Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia
- Institute of Molecular Genetics, National Research Council, Pavia, 27100, Italy
- Toxicology Research Division, Bureau of Chemical Safety Food Directorate, Health Products and Food Branch Health Canada, Ottawa, Ontario, K1A0K9, Canada
- Urology Department, Kasr Al-Ainy School of Medicine, Cairo University, El Manial, Cairo, 12515, Egypt
- Molecular Oncology Program, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington DC, 20057, USA
- Advenced Molecular Science Research Centre, King George’s Medical University, Lucknow, Uttar Pradesh, 226003, India
- Mediterranean Institute of Oncology, Viagrande, 95029, Italy
- Department of Internal Medicine, Korea Cancer Center Hospital, Seoul 139-706, South Korea
- Environmental and Molecular Toxicology, Environmental Health Science Center, Oregon State University, Corvallis, OR 97331, USA and
- Getting to Know Cancer, Truro, Nova Scotia, Canada
| | - Manaf Ali
- Sultan Zainal Abidin University, Malaysia
| | | | - Qiang (Shawn) Cheng
- Computer Science Department, Southern Illinois University, Carbondale, IL 62901, USA
| | - Leandro D’Abronzo
- Department of Urology, University of California Davis, Sacramento, CA 95817, USA
| | | | - Paramita M. Ghosh
- Department of Urology, University of California Davis, Sacramento, CA 95817, USA
| | - Michael J. Gonzalez Guzman
- University of Puerto Rico, Medical Sciences Campus, School of Public Health, Nutrition Program, San Juan Puerto Rico 00936-5067, USA
| | - Tae-Jin Lee
- Department of Anatomy, College of Medicine, Yeungnam University, Daegu, 705-717, South Korea
| | - Po Sing Leung
- School of Biomedical Science, The Chinese University Of Hong Kong, Hong Kong, China
| | - Lin Li
- School of Biomedical Science, The Chinese University Of Hong Kong, Hong Kong, China
| | - Suidjit Luanpitpong
- Siriraj Center of Excellence for Stem Cell Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Edward Ratovitski
- Department of Otolaryngology/Head and Neck Surgery, Head and Neck Cancer Research Division, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Yon Rojanasakul
- Department of Pharmaceutical Sciences, Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, WV 26506, USA
| | - Maria Fiammetta Romano
- Department of Molecular Medicine and Medical Biotechnology, Federico II University of Naples, 80131 Naples, Italy
| | - Simona Romano
- Department of Molecular Medicine and Medical Biotechnology, Federico II University of Naples, 80131 Naples, Italy
| | - Ranjeet K. Sinha
- Department of Molecular and Experimental Medicine, MEM 180, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Clement Yedjou
- Department of Biology, Jackson State University, Jackson, MS 39217, USA
| | - Fahd Al-Mulla
- Department of Pathology, Kuwait University, Safat 13110, Kuwait
| | | | - Amedeo Amedei
- Department of Experimental and Clinical Medicine, University of Firenze, Firenze, 50134, Italy
| | - Dustin G. Brown
- Department of Environmental and Radiological Health Sciences, Colorado state University/ Colorado School of Public Health, Fort Collins, CO 80523-1680, USA
| | - Elizabeth P. Ryan
- Department of Environmental and Radiological Health Sciences, Colorado state University/ Colorado School of Public Health, Fort Collins, CO 80523-1680, USA
| | - Anna Maria Colacci
- Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna, 40126, Italy
| | - Roslida A. Hamid
- Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia
| | - Chiara Mondello
- Institute of Molecular Genetics, National Research Council, Pavia, 27100, Italy
| | - Jayadev Raju
- Toxicology Research Division, Bureau of Chemical Safety Food Directorate, Health Products and Food Branch Health Canada, Ottawa, Ontario, K1A0K9, Canada
| | - Hosni K. Salem
- Urology Department, Kasr Al-Ainy School of Medicine, Cairo University, El Manial, Cairo, 12515, Egypt
| | - Jordan Woodrick
- Molecular Oncology Program, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington DC, 20057, USA
| | - A.Ivana Scovassi
- Institute of Molecular Genetics, National Research Council, Pavia, 27100, Italy
| | - Neetu Singh
- Advenced Molecular Science Research Centre, King George’s Medical University, Lucknow, Uttar Pradesh, 226003, India
| | - Monica Vaccari
- Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna, 40126, Italy
| | - Rabindra Roy
- Molecular Oncology Program, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington DC, 20057, USA
| | - Stefano Forte
- Mediterranean Institute of Oncology, Viagrande, 95029, Italy
| | - Lorenzo Memeo
- Mediterranean Institute of Oncology, Viagrande, 95029, Italy
| | - Seo Yun Kim
- Department of Internal Medicine, Korea Cancer Center Hospital, Seoul 139-706, South Korea
| | - William H. Bisson
- Environmental and Molecular Toxicology, Environmental Health Science Center, Oregon State University, Corvallis, OR 97331, USA and
| | - Leroy Lowe
- Getting to Know Cancer, Truro, Nova Scotia, Canada
| | - Hyun Ho Park
- *To whom correspondence should be addressed. Tel: +82 53 810 3015; Fax: +82 53 810 4619;
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Abliz G, Mijit F, Hua L, Abdixkur G, Ablimit T, Amat N, Upur H. Anti-carcinogenic effects of the phenolic-rich extract from abnormal Savda Munziq in association with its cytotoxicity, apoptosis-inducing properties and telomerase activity in human cervical cancer cells (SiHa). Altern Ther Health Med 2015; 15:23. [PMID: 25880193 PMCID: PMC4331379 DOI: 10.1186/s12906-015-0530-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 01/16/2015] [Indexed: 11/10/2022]
Abstract
BACKGROUND Abnormal Savda Munziq (ASMq) is a herbal preparation used in Traditional Uighur Medicine for the treatment cancer. The polyphenol is main compounds contained in ASMq preparation responsible for anticancer effect of ASMq. METHODS In this study,Real-time quantitative Polymerase Chain Reaction (RT-PCR) assay, MTT assay and flow cytometry were used to investigate the effect of polyphenol of ASMq on cell viability and the potential of the phenolic rich extracts of ASMq to induce apoptosis in human cervical cancer cells SiHa and its effects on telomerase activity were investigated. Cellular morphological change was observed by phase contrast microscopy. The MTT cell viability data revealed that treatment with phenolic rich extracts at 75 ~ 175 μg/ml significantly inhibited the viability and proliferation of cells, and these effects occurred in a concentration-dependent manner and time dependent manner (P < 0.01). RESULTS The phenolic rich extracts can induce apoptosis of SiHa cells, can increase the apoptosis rate in a concentration-dependent manner and time dependent manner (P < 0.01). Growth inhibition and apoptosis induction by phenolic rich extracts treatment on SiHa cells was associated with down-regulation of anti-apoptotic Bcl-2 expression and telomerase (P < 0.05) and Survivin expression. In addition, phenolic rich extracts exerted a dose-dependent induction of FHIT expression. CONCLUSION These results suggest that phenolic rich extracts may have anti-tumor effects in human cervical cancer through cytotoxicity, apoptosis-inducing properties and telomerase activity.
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Tan Y, Tan L, Huang S, Lu J, Yu L. Content Determination of Active Component in Huangqi Yinyanghuo Group and Its Effects on hTERT and Bcl-2 Protein in Osteosarcoma. JOURNAL OF ANALYTICAL METHODS IN CHEMISTRY 2014; 2014:769350. [PMID: 25371846 PMCID: PMC4211175 DOI: 10.1155/2014/769350] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 08/13/2014] [Accepted: 08/13/2014] [Indexed: 06/04/2023]
Abstract
To screen the optimal extraction process and content determination of active component of Huangqi Yinyanghuo group (HYG) and to study the effects of HYG on human telomerase reverse transcriptase (hTERT) and Bcl-2 protein in osteosarcoma (HOS) cells, providing the theoretical basis for clinical application of HYG in treatment of osteosarcoma, orthogonal design table L9(4(3)) was used to design the extraction process of HYG, and icariin was taken as the investigation index to optimize the extraction process of HYG. 0.125, 0.25, 0.5, 1, 2, 4, and 8 μmol/L HYG were taken to act separately on logarithmic growth phase osteosarcoma HOS cells, CCK-8 assay was used to determine cell viability, and immunohistochemical SP assay was used to determine the expression of hTERT and Bcl-2 protein. Apoptosis rate was positively correlated with the dose of HYG, and the expressions of hTERT and Bcl-2 protein were significantly decreased with the prolonged duration of action. Under the effect of HYG, dose was negatively correlated with osteosarcoma cell survival fraction; osteosarcoma cell survival fraction was positively correlated with hTERT and Bcl-2 protein; duration of action was negatively correlated with hTERT and Bcl-2 protein; and hTERT and Bcl-2 protein were in a synchronous relationship.
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Affiliation(s)
- Ying Tan
- Department of Spinal Surgery, Weifang Traditional Chinese Medicine Hospital, Weifang 261041, China
| | - Lei Tan
- Department of Spinal Surgery, Weifang Traditional Chinese Medicine Hospital, Weifang 261041, China
| | - Shuai Huang
- Department of Orthopaedic Surgery, The Sixth Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510655, China
| | - Junfan Lu
- Department of Spinal Surgery, Weifang Traditional Chinese Medicine Hospital, Weifang 261041, China
| | - Longtan Yu
- Department of Spinal Surgery, Weifang Traditional Chinese Medicine Hospital, Weifang 261041, China
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Moirangthem DS, Laishram S, Borah JC, Kalita MC, Talukdar NC. Cephalotaxus griffithii Hook.f. needle extract induces cell cycle arrest, apoptosis and suppression of hTERT and hTR expression on human breast cancer cells. Altern Ther Health Med 2014; 14:305. [PMID: 25135691 PMCID: PMC4155093 DOI: 10.1186/1472-6882-14-305] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 08/13/2014] [Indexed: 12/18/2022]
Abstract
Background Cephalotaxus spp. are known to possess anticancer potential. In this present work, for the first time the effects of C. griffithii needle (CGN) extracts on human cancer cells were examined. Methods The CGN was successively extracted with petroleum ether (PE), acetone and methanol. The extracts were tested for its effect on proliferation of cancer cells (MTT assay on HeLa, ZR751 and HepG2). Extract that showed the maximum growth inhibitory effect was subjected for mechanism of action study. These included apoptosis (morphological and DNA fragmentation assay), cell cycle (flow cytometry), caspase expression (Western blot) and activity (assay kit), p53 (western blot and TP53 siRNA interference) and telomerase expression (reverse transcriptase PCR) analysis. Results Among the extracts, PE extract induced maximum cytotoxicity, with highest death occurred in ZR751 cells. Since, PE extract induced cell death was highest among the CGN extracts, with maximum cancer cell death occurred in ZR751 cells; we carried out mechanism study of PE extract induced ZR751 cell death. It was observed that PE extract induced ZR751 cell death was associated with cell cycle arrest and apoptosis by activating both intrinsic and extrinsic apoptotic pathways. Knock down study revealed that p53 is essential for loss of ZR751 cell viability induced by PE extract. Further, PE extract down-regulated hTERT, hTR, and c-Myc expression. Thin layer chromatography analysis indicated the presence of unique phytochemicals in PE extract. Conclusion Based on the observations, we concluded that PE extract of C. griffithii needle contains important phyto-components with multiple cellular targets for control of breast cancer and is worthy of future studies. Electronic supplementary material The online version of this article (doi:10.1186/1472-6882-14-305) contains supplementary material, which is available to authorized users.
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Zhao YQ, Feng HW, Jia T, Chen XM, Zhang H, Xu AT, Zhang HL, Fan XL. Antiproliferative Effects of Celecoxib in Hep-2 Cells through Telomerase Inhibition and Induction of Apoptosis. Asian Pac J Cancer Prev 2014; 15:4919-23. [DOI: 10.7314/apjcp.2014.15.12.4919] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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18
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hTERT: Another brick in the wall of cancer cells. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2013; 752:119-128. [DOI: 10.1016/j.mrrev.2012.12.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 11/28/2012] [Accepted: 12/10/2012] [Indexed: 01/06/2023]
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Cheng G, Yu A, Dee MJ, Malek TR. IL-2R signaling is essential for functional maturation of regulatory T cells during thymic development. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2013; 190:1567-75. [PMID: 23315074 PMCID: PMC3563871 DOI: 10.4049/jimmunol.1201218] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
CD4(+) Foxp3(+) regulatory T cells (Tregs) are an independent cell lineage, and their developmental progression during thymic development depends on IL-2R signaling. However, the role of IL-2R signaling during thymic Treg development remains only partially understood. The current study assessed the contribution of IL-2 to the expansion and functional programming of developing Tregs. In the absence of IL-2Rβ signaling, predominantly CD4(+) CD25(-) Foxp3(lo) T cells were found, and these cells exhibited somewhat lower expression of the proliferative marker Ki67. These immature Tregs, which represent products of failed development, were also found in normal mice and were characterized by markedly lower expression of several Treg functional molecules. Therefore, IL-2R is required for the progression, functional programming, and expansion of Tregs during thymic development. An IL-2R-signaling mutant that lowers STAT5 activation readily supported Treg functional programming, but Treg proliferation remained somewhat impaired. The requirement for IL-2 during thymic Treg expansion was best illustrated in mixed chimeras where the Tregs with mutant IL-2Rs were forced to compete with wild-type Tregs during their development. Tregs with impaired IL-2R signaling were more prevalent in the thymus than spleen in these competitive experiments. The general effectiveness of mutant IL-2Rs to support thymic Treg development is partially accounted for by a heightened capacity of thymic Tregs to respond to IL-2. Overall, our data support a model in which limiting IL-2R signaling is amplified by thymic Tregs to readily support their development and functional programming, whereas these same conditions are not sufficient to support peripheral Treg homeostasis.
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Affiliation(s)
- Guoyan Cheng
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, Miami, FL 33101, USA
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Typical cell signaling response to ionizing radiation: DNA damage and extranuclear damage. Chin J Cancer Res 2013; 24:83-9. [PMID: 23357898 DOI: 10.1007/s11670-012-0083-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2011] [Accepted: 01/15/2012] [Indexed: 12/15/2022] Open
Abstract
To treat many types of cancer, ionizing radiation (IR) is primarily used as external-beam radiotherapy, brachytherapy, and targeted radionuclide therapy. Exposure of tumor cells to IR can induce DNA damage as well as generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) which can cause non-DNA lesions or extracellular damage like lipid perioxidation. The initial radiation-induced cell responses to DNA damage and ROS like the proteolytic processing, as well as synthesis and releasing ligands (such as growth factors, cytokines, and hormone) can cause the delayed secondary responses in irradiated and unirradiated bystander cells through paracrine and autocrine pathways.
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YInglong X, Hui L, Junli W, Min X. Effect of liposomal transfection of hTERT on Apoptosis of newborn rat cochlear basilar membrane cells. J Otol 2012. [DOI: 10.1016/s1672-2930(12)50025-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Abstract
We have analysed telomerase activity to determine whether it can be modified when BCL-2 is endogenously overexpressed in response to a mild oxidative stress treatment as part of a survival mechanism, in contrast with an exogenous bcl-2 overexpression due to a retroviral infection. Endogenous bcl-2 overexpression was induced after a low oxidative insult of H2O2 in mice primary lung fibroblasts and L929 cell, whereas bcl-2 exogenous overexpression was performed using a retroviral infection in L929 cells. Telomerase activity was quantified in Bcl-2 overexpressing cells by the TRAP assay. When the cells were treated with different H2O2 concentrations, only those exposed to 50 μM showed increased telomerase activity. This correlates with BCL-2 expression as part of the endogenous response to mild oxidative stress. Oxidative stress generated during the toxic mechanism of chemotherapeutic drugs might induce BCL-2 increment, enhancing telomerase activity and reactivating the oncogenic process. Clinical trials should take into consideration the possibility of telomerase activation following increased BCL-2 expression when treating patients with ROS (reactive oxygen species) generation by anti-cancer drugs.
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Park YP, Choi SC, Cho MY, Song EY, Kim JW, Paik SG, Kim YK, Kim JW, Lee HG. Modulation of telomerase activity and human telomerase reverse transcriptase expression by caspases and bcl-2 family proteins in Cisplatin-induced cell death. Korean J Lab Med 2012; 26:287-93. [PMID: 18156740 DOI: 10.3343/kjlm.2006.26.4.287] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Human telomerase is a ribonucleoprotein polymerase, which synthesizes telomeric repeat sequences, and human telomerase reverse transcriptase (hTERT) has been identified as the catalytic subunit, as well as the rate-limiting component, of telomerase. In this study, we attempted to identify the modulators of telomerase, and to determine the molecular mechanisms underlying cisplatin-induced apoptosis. METHODS To determine the role of telomerase in cisplatin-induced apoptosis, we measured telomerase activity and analyzed apoptosis using PI and trypan blue staining. Also, we inhibited the caspase activations using Z-VAD-fmk to analyze the effects on expression of hTERT protein. Finally, we induced the transient co-expression of the Bcl-2 and Bak genes in HEK293 cells, and then, the telomerase activity and expression of hTERT were evaluated. RESULTS In the Bcl-2-overexpressing HeLa cells, telomerase activity was more enhanced, and cell death was reduced to 40-50% that of the mock controls. This finding suggests that Bcl-2-induced telomerase activity exerts an antiapoptotic effect in cisplatin-induced death. As caspase activation was inhibited via Z-VAD-fmk, the hTERT protein was recovered in the mock controls, but not in the Bcl-2-overexpressing cells. This suggests that the expression of hTERT can be regulated by caspases, but Bcl-2 was located within the upstream pathway. Moreover, when the Bcl-2 and Bak genes were co-transfected into the HEK293, both telomerase activity and hTERT protein were prominently reduced. CONCLUSIONS Bcl-2-induced telomerase activity inhibits cisplatin-induced apoptosis in HeLa cells, and can be regulated via both caspases and the interaction of Bcl-2 and Bak.
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Affiliation(s)
- Yuk Pheel Park
- Cellomics Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea.
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Ye B, Ji ZN. 23-hydroxybetulinic acid-induced HL-60 cell autophagic apoptosis and its molecular mechanism. Nat Prod Res 2012; 26:1063-8. [DOI: 10.1080/14786419.2011.559639] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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25
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Liu Z, Zhuang J, Li C, Wan P, Li N, Zhou Q, Zhou C, Huang Z, Wang Z. Long-term cultivation of human corneal endothelial cells by telomerase expression. Exp Eye Res 2012; 100:40-51. [PMID: 22575565 DOI: 10.1016/j.exer.2012.04.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 04/18/2012] [Accepted: 04/23/2012] [Indexed: 12/13/2022]
Abstract
The objective of this study was to explore the potential role of human telomerase reverse transcriptase (TERT) in extending the proliferative lifespan of human corneal endothelial cells (HCECs) under long-term cultivation. A primary culture was initiated with a pure population of HCECs in DMEM/F12 media containing 10% fetal bovine serum and other various supplements. TERT gene was successfully transfected into normal HCECs. A stable HCECs cell line (TERT-HCECs) that expressed TERT was established. The cells could be subcultured for 36 passages. Within this line of cells, TERT not only extended proliferative lifespan and inhibited apoptosis but also enhanced the cell line remaining the normal characteristics similar to HCECs. There were no significantly differences in the expression of the pump function related proteins voltage dependent anion channel 3 (VDAC3), sodium bicarbonate cotransporter member 4 (SLC4A4), chloride channel protein 3 (CLCN3), Na(+)/K(+)-ATPase α1, and ZO-1 in the cell line TERT-HCECs and primary HCECs. TERT-HCECs formed a monolayer cell sheet, maintained similar cell junction formation and pump function with primary HCECs. Karyotype analysis exhibited normal chromosomal numbers. The soft agar colony assay and tumor formation in nude mice assay showed no malignant alterations in TERT-HCECs. Our findings indicated that we had established a cell line with its similar phenotype and properties to primary HCECs. Further study of the TERT-HCECs may be valuable in studying the function of the cells in vivo.
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Affiliation(s)
- Zhiping Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
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Xie WZ, Lin MF, Huang H, Cai Z. Homoharringtonine-Induced Apoptosis of Human Leukemia HL-60 Cells is Associated with Down-Regulation of Telomerase. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2012; 34:233-44. [PMID: 16552835 DOI: 10.1142/s0192415x06003795] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Homoharringtonine (HHT), first isolated from the Chinese evergreen Cephalotaxus Harringtonia, has been shown inhibiting activity in leukemia in initial studies in China and in later studies in the US, but the detailed mechanism of action is still unclear. The goal of the experiments shown here is to explore the effect of HHT on the telomerase activity and apoptosis of human leukemia HL-60 cells. The telomerase activity of HL-60 cells was examined by the telomeric repeat amplification protocol (TRAP) — an enzyme-linked immunosorbent assay (ELISA). Apoptosis was analyzed by morphological observation, DNA agarose gel electrophoresis, flow cytometry (FCM), and TdT-mediated dUTP-biotin nick end labeling (TUNEL). After treatment with HHT at 5–500 μg/l for 48 hours, the level of telomerase activity in HL-60 cells decreased in a dose-and time-dependent manner. Simultaneously, HL-60 cells underwent apoptosis. In conclusion, our data suggest that HHT can inhibit the telomerase content of HL-60 cells effectively and induce apoptosis.
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Affiliation(s)
- Wan-Zhuo Xie
- First Affiliated Hospital, Medical College of Zhejiang University, Hangzhou 310003, China.
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27
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SHI Y, CUI YH, WU HG, ZHANG W, ZHAO C, LIU HR, GUO LQ, WU BL, YU AZ, ZHANG YY. Effects of mild-warming moxibustion on Bcl-2 and PKC expressions of peripheral blood in elderly people. J TRADIT CHIN MED 2012; 32:45-51. [DOI: 10.1016/s0254-6272(12)60030-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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l-Securinine induced the human colon cancer SW480 cell autophagy and its molecular mechanism. Fitoterapia 2011; 82:1258-64. [DOI: 10.1016/j.fitote.2011.08.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 08/17/2011] [Accepted: 08/20/2011] [Indexed: 11/21/2022]
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Gao LW, Zhang J, Yang WH, Wang B, Wang JW. Glaucocalyxin A induces apoptosis in human leukemia HL-60 cells through mitochondria-mediated death pathway. Toxicol In Vitro 2010; 25:51-63. [PMID: 20851175 DOI: 10.1016/j.tiv.2010.09.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 08/19/2010] [Accepted: 09/13/2010] [Indexed: 10/19/2022]
Abstract
Glaucocalyxin A (GLA) is a biologically active ent-kauranoid diterpenoid isolated from Rabdosia japonica var. glaucocalyx, a traditional Chinese medicinal herb, which has been shown to inhibit tumor cell proliferation. However, the mechanism underlying GLA-induced cytotoxicity remains unclear. In this study, we focused on the effect of GLA induction on apoptosis, the mitochondria-mediated death pathway and the accumulation of reactive oxygen species (ROS) in human leukemia cells (HL-60). GLA could induce a dose-dependent apoptosis in HL-60 cells as characterized by cell morphology, DNA fragmentation, activation of caspase-3, -9 and an increased expression ratio of Bax/Bcl-2. The mitochondrial membrane potential (Δψ(m)) loss and cytochrome c release from mitochondria to cytosol were observed during the induction. Moreover, GLA caused a time- and dose-dependent elevation of intracellular ROS level in HL-60 cells, and N-acetyl-l-cysteine (NAC, a well-known antioxidant) could block GLA-induced ROS generation and apoptosis. These data suggest that GLA induces apoptosis in HL-60 cells through ROS-dependent mitochondrial dysfunction pathway.
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Affiliation(s)
- Li Wen Gao
- School of Pharmaceutical Sciences, Soochow University, Suzhou, PR China
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Moon DO, Kang CH, Kim MO, Jeon YJ, Lee JD, Choi YH, Kim GY. Beta-lapachone (LAPA) decreases cell viability and telomerase activity in leukemia cells: suppression of telomerase activity by LAPA. J Med Food 2010; 13:481-8. [PMID: 20438329 DOI: 10.1089/jmf.2008.1219] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Up-regulation of telomerase activity is associated with immortalization and unlimited cell division in most cancer cells. Therefore, telomerase represents a particularly attractive target for anticancer therapy. Recent reports have suggested that beta-lapachone (LAPA), the product of the South American Tabebuia avellanedae tree, inhibits growth of tumor cells. However, the underlying relationship between telomerase activity and apoptosis in response to LAPA exposure in leukemia cells remains poorly understood. In this study, we confirmed that LAPA treatment induces direct cytotoxicity in human leukemia cells (U937, K562, HL60, and THP-1) through activation of caspase-3 and subsequent cleavage of poly(ADP-ribose) polymerase. The observed induction of cell death was associated with decreased telomerase activity, which was ascribed to down-regulation of telomerase reverse transcriptase. Additionally, overexpression of anti-apoptotic Bcl-2 could not overcome the induction of apoptosis or the decreased telomerase activity in response to treatment of U937 cells with LAPA. We conclude that LAPA has a direct cytotoxic effect and the loss of telomerase activity in leukemia cells.
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Affiliation(s)
- Dong-Oh Moon
- Department of Marine Sciences, Jeju National University, Jeju, Republic of Korea
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Park SE, Yoo HS, Jin CY, Hong SH, Lee YW, Kim BW, Lee SH, Kim WJ, Cho CK, Choi YH. Induction of apoptosis and inhibition of telomerase activity in human lung carcinoma cells by the water extract of Cordyceps militaris. Food Chem Toxicol 2009; 47:1667-75. [PMID: 19393284 DOI: 10.1016/j.fct.2009.04.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Revised: 03/27/2009] [Accepted: 04/15/2009] [Indexed: 01/01/2023]
Abstract
Cordyceps militaris is well known as a traditional medicinal mushroom and is a potentially interesting candidate for use in cancer treatment. In this study, the potential of the water extract of C. militaris (WECM) to induce apoptosis in human lung carcinoma A549 cells and its effects on telomerase activity were investigated. The growth inhibition and apoptosis induction by WECM treatment in A549 cells was associated with the induction of Fas, catalytic activation of caspase-8, and Bid cleavage. Activation of caspases, downregulation of anti-apoptotic Bcl-2 expression, and upregulation of pro-apoptotic Bax protein were also observed in WECM-treated cells. However, the cytotoxic effects and apoptotic characteristics induced by WECM were significantly inhibited by z-DEVD-fmk, a caspase-3 inhibitor, which demonstrates the important role that caspase-3 plays in the process. In addition, WECM exerted a dose-dependent inhibition of telomerase activity via downregulation of human telomerase reverse transcriptase (hTERT), c-myc and Sp1 expression. Taken together, the data from this study indicate that WECM induces the apoptosis of A549 cells through a signaling cascade of death receptor-mediated extrinsic and mitochondria-mediated intrinsic caspase pathways. It was also conclude that apoptotic events due to WECM were mediated with diminished telomerase activity through the inhibition of hTERT transcriptional activity.
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Affiliation(s)
- Sang Eun Park
- Department of East-West Cancer Center, College of Oriental Medicine, Daejeon University, Daejeon 301-724, Republic of Korea
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Park YP, Kim KD, Kang SH, Yoon DY, Park JW, Kim JW, Lee HG. Human telomerase reverse transcriptase (hTERT): a target molecule for the treatment of cisplatin-resistant tumors. Korean J Lab Med 2009; 28:430-7. [PMID: 19127107 DOI: 10.3343/kjlm.2008.28.6.430] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Human telomerase reverse transcriptase (hTERT) is a catalytic enzyme that is required for telomerase activity (TA) and cancer progression. Telomerase inhibition or inactivation increases cellular sensitivity to UV irradiation, DNA-damaging agents, the tyrosine kinase inhibitor, imatinib, and pharmacological inhibitors, such as BIBR1532. hTERT is associated with apoptosis. Some patients show drug-resistance during anti-cancer drug treatment and the cancer cell acquire anti-apoptotic mechanism. Therefore, we attempted to study correlation between hTERT and drug-resistance. METHODS To study the correlation between protein level and activity of hTERT and drug-resistance, Western blotting and telomerase repeat amplification protocol (TRAP) assays were performed. To investigate whether hTERT contributes to drug resistance in tumor cells, we transiently decreased hTERT levels using small interfering RNA (siRNA) in T24/R2 cells. RESULTS hTERT knockdown increased Bax translocation into the mitochondria and cytochrome C release into the cytosol. Caspase inhibitors, especially Z-VAD-FMK, rescued this phenomenon, suggesting that the stability or expression of hTERT might be regulated by caspase activity. CONCLUSIONS These data suggest that hTERT might be a target molecule for drug-resistant tumor therapy.
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Affiliation(s)
- Yuk Pheel Park
- Medical Genomic Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea
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Prognostic relevance of hTERT mRNA expression in ductal adenocarcinoma of the pancreas. Neoplasia 2009; 10:973-6. [PMID: 18714398 DOI: 10.1593/neo.08578] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Revised: 06/17/2008] [Accepted: 06/20/2008] [Indexed: 12/18/2022] Open
Abstract
Telomerase is thought to play an essential role in tumorigenesis and progression. Its activity is directly correlated with the expression of its catalytic subunit, human telomerase reverse transcriptase (hTERT). A correlation of transcript expression with a poor prognosis has been detected in different human malignancies. However, data on hTERT in pancreatic ductal adenocarcinoma (PDAC) are purely descriptive so far. Therefore, we evaluated the impact of hTERT expression on patients' prognosis. Human telomerase reverse transcriptase mRNA isolates from 56 human microdissected PDAC tissues were analyzed by quantitative reverse transcription-polymerase chain reaction and multivariate Cox regression hazard test. Elevated hTERT transcript levels were measured in 23 of 56 PDAC tissues, 33 patients showed no detectable transcripts. Unexpectedly, a low expression of hTERT mRNA levels was associated with a worse prognosis for overall survival (relative risk = 5.33; P = .013) when compared to high levels, whereas undetectable expression showed an intermediate risk of tumor-related death. These data challenge previous findings outlining hTERT's negative impact on overall survival. The risk pattern obtained in PDAC suggests a more complex regulation of hTERT.
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Antisense human telomerase reverse transcriptase could partially reverse malignant phenotypes of gastric carcinoma cell line in vitro. Eur J Cancer Prev 2008; 17:209-17. [PMID: 18414191 DOI: 10.1097/cej.0b013e3282b71f0d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Telomerase activity is detected in more than 90% of examined tumors but not in most normal somatic cells. Among three subunits of human telomerase, human telomerase reverse transcriptase (hTERT) is the rate-limiting component for telomerase activity. Therefore, targeting hTERT represents a promising approach for diminishing telomerase function that will probably not cause substantial side effects on telomerase negative somatic cells. To explore the effects of antisense hTERT (ahTERT) on the malignant phenotypes of human SGC-7901 gastric cancer cell line in vitro, an antisense eukaryotic expression vector of hTERT was constructed by gene recombinant technology. Telomerase activity by telomeric repeat amplification protocol-ELISA, mRNA of telomerase subunits, c-myc and bcl-2 by reverse transcript-PCR, terminal restriction fragment (TRF) by Southern blot, cell cycle distribution by flow cytometry and protein expression of hTERT, c-myc and bcl-2 by Western blot were analyzed in SGC-7901 cells before and after transfection. Cloning efficiency assay in soft agar and tumorigenesis in nude mice were also examined and evaluated in the above cells. The results demonstrated that after ahTERT transfection, the proliferation of SGC-7901 cells was significantly inhibited. Further study showed that telomerase activity, telomere length, the mRNA and protein expression of hTERT, bcl-2 and c-myc were decreased in ahTERT-transfected cells. There were, however, no obvious effects on transcription of human telomerase RNA (hTR) and human telomerase associated protein1 (TP1) in both transfected and untransfected cells. Flow cytometric analysis displayed an accumulation of G0/G1 phase and a decreasing proliferation index (PI) in ahTERT-transfected cells. Moreover, no tumorigenicity was found after subcutaneous injection of ahTERT-transfected cells in nude mice, whereas palpable tumors were observed in mice injected with control cells. Our study indicates that exogenous ahTERT can inhibit proliferation and partially reverse malignant phenotypes of SGC-7901 cells via the suppression of telomerase activity, hTERT, c-myc and bcl-2 expression. Antisense technology targeted hTERT strategy might be a potential approach for gastric cancer therapy.
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Natarajan M, Mohan S, Konopinski R, Otto RA, Herman TS. Induced telomerase activity in primary aortic endothelial cells by low-LET gamma-radiation is mediated through NF-kappaB activation. Br J Radiol 2008; 81:711-20. [PMID: 18541630 DOI: 10.1259/bjr/57867919] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Our objective was to understand the mechanism through which cells that initially survive irradiation could acquire survival advantage. In this study, we show evidence that low-linear energy transfer gamma-radiation can induce telomerase enzyme activity in primary aortic endothelial cells, and that an upstream regulator, nuclear factor kappa B (NF-kappaB), controls this activation. Telomeric repeat amplification protocol (TRAP) assay showed that cells exposed to a dose of 2 Gy induce telomerase activity. Subsequent analysis revealed that radiation-induced telomeric activity is regulated at the transcriptional level by triggering activation of the promoter of the telomerase catalytic subunit, telomerase reverse transcriptase (TERT). A mechanistic study revealed that NF-kappaB becomes functionally activated upon radiation exposure and mediates the upregulation of telomerase activity by binding to the kappaB-binding region in the promoter region of the TERT gene. More significantly, elimination of the NF-small ka, CyrillicB recognition site on the telomerase promoter or inhibition of NF-small ka, CyrillicB by ectopically expressing the inhibitor protein IkappaBalpha mutant (Ismall ka, CyrillicBalpha(S32A/S36A))) compromises radiation-induced telomerase promoter activation. Consistent with the notion that NF-kappaB mediates gamma-ray-induced telomerase responses, TRAP assay revealed that ectopically expressed IkappaBalpha(S32A/S36A)) also attenuated telomerase enzyme activity. These findings indicate that NF-kappaB activation following ionizing radiation exposure may elicit a survival advantage by upregulating and maintaining telomerase activity.
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Affiliation(s)
- M Natarajan
- Department of Radiation Oncology, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
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Xu Q, Zhang Z, Zhang P, Chen W. Antisense oligonucleotides and all-trans retinoic acid have a synergistic anti-tumor effect on oral squamous cell carcinoma. BMC Cancer 2008; 8:159. [PMID: 18522733 PMCID: PMC2427037 DOI: 10.1186/1471-2407-8-159] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Accepted: 06/03/2008] [Indexed: 04/04/2023] Open
Abstract
Background Antisense oligonucleotides against hTR (As-ODN-hTR) have shown promising results as treatment strategies for various human malignancies. All-trans retinoic acid (ATRA) is a signalling molecule with important roles in differentiation and apoptosis. Biological responses to ATRA are currently used therapeutically in various human cancers. The aim of this study was to evaluate the anti-tumor effects of As-ODN-hTR combined with ATRA in vivo. Methods In situ human oral squamous cell carcinoma (OSCC) models were established by subcutaneous injection of Tca8113 cells. Mice were treated with sense oligonucleotides against hTR(S-ODN-hTR) alone, As-ODN-hTR alone, ATRA alone, As-ODN-hTR plus ATRA, or S-ODN-hTR plus ATRA. Tumor size and weight were assessed in the mice. Telomerase activity was detected by a TRAP assay, apoptotic cells were evaluated with a Tunel assay, the expression of apoptosis-related proteins (Bcl-2 and Bax) was evaluated by immunohistochemistry and ultrastructural morphological changes in the tumor specimen were examined. Results Both As-ODN-hTR and ATRA can significantly inhibit tumor growth in this OSCC xenograft solid-tumor model, and the combination of the two agents had a synergistic anti-tumorogenic effect. We also demonstrated that this anti-tumor effect correlated with inhibition of telomerase activity. Furthermore, significant increases in the number of apoptotic cells, typical apoptotic morphology and a downregulation of the anti-apoptotic protein, bcl-2 were observed in the treated tissues. Conclusion The combination of As-ODN-hTR and ATRA has a synergistic anti-tumor effect. This anti-tumor effect can be mainly attributed to apoptosis induced by a decrease in telomerase activity. Bcl-2 plays an important role in this process. Therefore, combining As-ODN-hTR and ATRA may be an approach for the treatment of human oral squamous cell carcinoma.
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Affiliation(s)
- Qin Xu
- Department of Oral and Maxillofacial Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, 639, Zhizaoju Road, Shanghai 200011, PR China.
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Yang Y, An J, Weng NP. Telomerase is involved in IL-7-mediated differential survival of naive and memory CD4+ T cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2008; 180:3775-81. [PMID: 18322183 PMCID: PMC2367009 DOI: 10.4049/jimmunol.180.6.3775] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
IL-7 plays an essential role in T cell maintenance and survival. The survival effect of IL-7 is thought to be mediated through regulation of Bcl2 family proteins. After a comparative analysis of IL-7-induced growth and cell death of human naive and memory CD4(+) T cells, we observed that more memory CD4(+) T cells underwent cell division and proceeded to apoptosis than naive cells in response to IL-7. However, IL-7-induced expressions of Bcl2 family members (Bcl2, Bcl-x(L), Bax, and Bad) were similar between naive and memory cells. Instead, we found that IL-7 induced higher levels of telomerase activity in naive cells than in memory cells, and the levels of IL-7-induced telomerase activity had a significant inverse correlation with cell death in CD4(+) T cells. Furthermore, we showed that reducing expression of telomerase reverse transcriptase and telomerase activity significantly increased cell death of IL-7-cultured CD4(+) T cells. Together, these findings demonstrate that telomerase is involved in IL-7-mediated differential survival of naive and memory CD4(+) T cells.
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Affiliation(s)
- Yinhua Yang
- Laboratory of Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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Wang FZ, Sha L, Ye LH, Zhang XD. Promotion of cell proliferation by HBXIP via upregulation of human telomerase reverse transcriptase in human mesenchymal stem cells. Acta Pharmacol Sin 2008; 29:83-9. [PMID: 18158869 DOI: 10.1111/j.1745-7254.2008.00729.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
AIM We previously found that the hepatitis B X-interacting protein (HBXIP) was able to promote the proliferation of cells. Telomerase activity is known to be critical in cellular senescence and its level is modulated by the regulation of the telomerase catalytic subunit, telomerase reverse transcriptase (TERT), at both the transcriptional and post-transcriptional levels. To investigate the mechanism of promoting proliferation by HBXIP, the effect of HBXIP on human TERT (hTERT) was investigated in human mesenchymal stem cells (hMSC). METHODS BMMS-03 cells and hMSC from the bone marrow of a 4-month-old elicited fetus, were transiently transfected with the pcDNA3-hbxip plasmid encoding the HBXIP gene and pSilencer-hbxip plasmid encoding RNA interference (RNAi) targeting HBXIP mRNA, followed by the examination of the hTERT promoter reporter gene by luciferase assay, and the detection of telomerase activity by telomeric repeat amplication protocol, respectively, as well as the expression levels of hTERT, c-Myc, and Bcl-2 by Western blot analysis. RESULTS The overexpression of HBXIP led to a significant upregulation of hTERT promoter activity, telomerase activity, and the expression levels of hTERT, c-Myc, and Bcl-2 in BMMS-03 cells. RNAi targeting HBXIP mRNA produced the opposite results completely. CONCLUSION Our data demonstrated that HBXIP significantly stimulated the transcription and expression of hTERT and increased the activity of telomerase in BMMS-03 cells, which provides a new insight into the mechanism of promoting cell proliferation by HBXIP.
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Affiliation(s)
- Feng-ze Wang
- Departments of Biochemistry, Tianjin Key Laboratory of Microbial Functional Genomics, Institute for Molecular Biology, College of Life Sciences, Nankai University, Tianjin, China
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Bermudez Y, Erasso D, Johnson NC, Alfonso MY, Lowell NE, Kruk PA. Telomerase confers resistance to caspase-mediated apoptosis. Clin Interv Aging 2007; 1:155-67. [PMID: 18044112 PMCID: PMC2695162 DOI: 10.2147/ciia.2006.1.2.155] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
There is growing evidence that accelerated telomeric attrition and/or aberrant telomerase activity contributes to pathogenesis in a number of diseases. Likewise, there is increasing interest to develop new therapies to restore or replace dysfunctional cells characterized by short telomeric length using telomerase-positive counterparts or stem cells. While telomerase adds telomeric repeats de novo contributing to enhanced proliferative capacity and lifespan, it may also increase cellular survival by conferring resistance to apoptosis. Consequently, we sought to determine the involvement of telomerase for reduced apoptosis using ovarian surface epithelial cells. We found that expression of hTERT, the catalytic component of telomerase, was sufficient and specific to reduce caspase-mediated cellular apoptosis. Further, hTERT expression reduced activation of caspases 3, 8, and 9, reduced expression of pro-apoptotic mitochondrial proteins t-BID, BAD, and BAX and increased expression of the anti-apoptotic mitochondrial protein, Bcl-2. The ability of telomerase to suppress caspase-mediated apoptosis was p-jnk dependent since abrogation of jnk expression with jip abolished resistance to apoptosis. Consequently, these findings indicate that telomerase may promote cellular survival in epithelial cells by suppressing jnk-dependent caspase-mediated apoptosis.
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Affiliation(s)
- Yira Bermudez
- Department of Pathology, University of South Florida and the H Lee Moffitt Cancer Center, Tampa, FL 33612, USA
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Inhibition of the proliferation of human gastric cancer cells SGC-7901 in vitro and in vivo using Bcl-2 siRNA. Chin Med J (Engl) 2007. [DOI: 10.1097/00029330-200712010-00008] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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Sun YQ, Guo TK, Xi YM, Chen C, Wang J, Wang ZR. Effects of AZT and RNA-protein complex (FA-2-b-β) extracted from Liang Jin mushroom on apoptosis of gastric cancer cells. World J Gastroenterol 2007; 13:4185-91. [PMID: 17696246 PMCID: PMC4250616 DOI: 10.3748/wjg.v13.i31.4185] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the synergistic effects of 3'-azido-3'-deoxythymidine (AZT) and FA-2-b-β extracted from Ling Jin mushroom on apoptosis of gastric cancer cells MKN45 in vitro.
METHODS: MTT analysis was made to examine the inhibition rate of MKN45 cells treated with AZT (2.5, 5, 10 and 20 mg/L) and FA-2-b-β (5, 10, 20 and 40 mg/L) singly and combinatively for 24, 48 and 72 h. Apoptotic effects were evaluated by morphological methods, DNA agarose gel electrophoresis and flow cytometry, respectively. Telomerase activity was estimated by TRAP-ELISA. The mRNA expression of caspase-3 and Bcl-2 were detected by RT-PCR.
RESULTS: AZT and FA-2-b-β could significantly inhibit MKN45 cell proliferation and induce its apoptosis. MKN45 cells were inhibited in dose- and time- dependent manner. The inhibition effect of AZT combined with FA-2-b-β was obviously better than that used singly (0.469 ±0.022 vs 1.075 ± 0.055, P < 0.05, 0.325 ± 0.029 vs 0.469± 0.022 P < 0.01). AZT used singly and combination of FA-2-b-β could decrease the activity of tumor cell telomerase, and AZT has synergistic function with FA-2-b-β. A certain concentration of AZT could up-regulate the expression of caspase-3 mRNA (r = 0.9969, P < 0.01), which was positively related to apoptosis rate, and could down-regulate the expression of Bcl-2 mRNA, which was negatively related to apoptosis rate (r = 0.926, P < 0.01). Furthermore, the effect of AZT combined with FA-2-b-β was significantly higher than that used singly.
CONCLUSION: Combination of AZT and FA-2-b-β has an obviously synergetic effect in the gastric cancer cells MKN45, which has provided a new approach to the treatment of gastric cancer clinically.
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Affiliation(s)
- Yan-Qing Sun
- School of Life Science, Lanzhou University, Lanzhou 730000, Gansu Province, China
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Wang Q, Kou YW. Study of the expressions of p53 and bcl-2 genes, the telomerase activity and apoptosis in GIST patients. World J Gastroenterol 2007; 13:2626-8. [PMID: 17552015 PMCID: PMC4146828 DOI: 10.3748/wjg.v13.i18.2626] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To explore the relationship between clinicobiological behavior and the expression levels of telomerase activity, apoptosis, p53 gene and bcl-2 gene in gastrointestinal stromal tumors (GISTs).
METHODS: The intensity of telomerase activity, apoptosis, p53 and bcl-2 expression in GISTs were detected by telomeric repeat amplification protocol, in situ end-labeling technique, and immunohistochemistry, respectively.
RESULTS: The positive rates of telomerase activity of malignant GIST, potential malignant GIST and benign GIST were 85% (17/20), 22.8% (2/9) and 0 (0/9), respectively. The apoptosis indices of malignant GIST, potential malignant GIST, and benign GIST were 11.7 ± 5.4, 30.2 ± 5.6 and 45.2 ± 7.2, respectively. The intensity of telomerase activity and apoptosis were related to the biological characteristics of GISTs (85% vs 22.8%, 0, 0; P < 0.01 or 11.7 ± 5.4 vs 30.2 ± 5.6, 45.2 ± 7.2, 72.1 ± 9.3; P < 0.05). The intensity of telomerase activity was negatively correlated with cellular apoptosis (22.9 ± 8.4 vs 9.5 ± 5.7, P < 0.01). The intensity of telomerase activity was positively correlated with p53, bcl-2 expression (40.0% vs 78.9%, 40.0% vs 84.2%; P < 0.05).
CONCLUSION: The detection of telomerase activity, apoptosis and its control genes in GIST will be helpful for the discrimination of the malignant and benign GIST and evaluation of the prognosis.
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Affiliation(s)
- Qiang Wang
- Department of Gastrointestinal Surgery, Shenjing Hospital of China Medical University, Shenyang, Liaoning Province, China.
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Park C, Kim GY, Kim WI, Hong SH, Park DI, Kim ND, Bae SJ, Jung JH, Choi YH. Induction of Apoptosis by (Z)-Stellettic Acid C, an Acetylenic Acid from the Sponge Stelletta sp., Is Associated with Inhibition of Telomerase Activity in Human Leukemic U937 Cells. Chemotherapy 2007; 53:160-8. [PMID: 17356266 DOI: 10.1159/000100809] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Accepted: 06/13/2006] [Indexed: 01/04/2023]
Abstract
BACKGROUND (Z)-stellettic acid C, an acetylenic acid from the marine sponge Stelletta sp., has been shown to have cytotoxic activity in some cancer cells; however, its mechanisms on malignant cell growth are not known. In this study, the potential of (Z)-stellettic acid C to induce apoptosis in human leukemic U937 cells and its effects on telomerase activity were investigated. METHODS Cytotoxicity was evaluated by MTT assays. Apoptosis was detected using DAPI staining and annexin V fluorescein. The mRNAs of Bcl-2, inhibitor of apoptosis proteins (IAPs) family and Fas/FasL system were determined by RT-PCR. Caspases and telomerase activities were measured using colorimetric assay and telomeric repeat amplification protocol enzyme-linked immunosorbent assay (TRAP-ELISA), respectively. RESULTS Exposure of U937 cells to (Z)-stellettic acid C resulted in growth inhibition and induction of apoptosis in a dose-dependent manner, which was associated with the modulation of Bcl-2 family expression, activation of caspases and downregulation of IAPs family members. (Z)-Stellettic acid C treatment markedly inhibited the activity of telomerase in a dose-dependent fashion. Additionally, the expression of human telomerase reverse transcriptase, a main determinant of the telomerase enzymatic activity, was progressively downregulated by (Z)-stellettic acid C treatment. CONCLUSIONS These results suggest that (Z)-stellettic acid C could have a possible cancer therapeutic potential.
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Affiliation(s)
- Cheol Park
- Department of Oriental Medicine, Dongeui University College of Oriental Medicine, Busan, Korea
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Woo HJ, Lee SJ, Choi BT, Park YM, Choi YH. Induction of apoptosis and inhibition of telomerase activity by trichostatin A, a histone deacetylase inhibitor, in human leukemic U937 cells. Exp Mol Pathol 2007; 82:77-84. [PMID: 16574101 DOI: 10.1016/j.yexmp.2006.02.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Accepted: 02/08/2006] [Indexed: 11/25/2022]
Abstract
The objective of the present study was to investigate the effect of trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, on the cell growth and apoptosis and its effect on the telomerase activity in human leukemic cell line U937. Exposure of U937 cells to TSA resulted in growth inhibition and induction of apoptosis in a dose-dependent manner as measured by hemocytometer counts, fluorescence microscopy, agarose gel electrophoresis and flow cytometry analysis. The increase in apoptosis was associated with the up-regulation in proapoptotic Bax expression and down-regulation of antiapoptotic Bcl-2 and Bcl-X(L). TSA treatment inhibited the levels of cIAP family members and induced the proteolytic activation of caspase-3, which was associated with concomitant degradation of poly(ADP-ribose)-polymerase and beta-catenin protein. TSA treatment markedly inhibited the activity of telomerase in a dose-dependent fashion. Additionally, the expression of human telomerase reverse transcriptase (hTERT), a main determinant of the telomerase enzymatic activity, was progressively down-regulated by TSA treatment. We therefore conclude that TSA demonstrated antiproliferative and apoptosis-inducing effects on U937 cells in vitro, and that changes in Bcl-2 family protein levels as well as telomerase activity may play an important role in its mechanism of action.
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Affiliation(s)
- Hyun Joo Woo
- Department of Biochemistry, Dongeui University College of Oriental Medicine, Busan 614-052, South Korea
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45
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Hrdlicková R, Nehyba J, Liss AS, Bose HR. Mechanism of telomerase activation by v-Rel and its contribution to transformation. J Virol 2007; 80:281-95. [PMID: 16352553 PMCID: PMC1317554 DOI: 10.1128/jvi.80.1.281-295.2006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Telomerase is activated during the transformation of lymphoid cells and fibroblasts by v-Rel, the oncogenic member of the Rel/NF-kappaB family of transcription factors. v-Rel-transformed cell lines have longer telomeres than untransformed chicken lymphoid cells and have high levels of telomerase activity. v-Rel-mediated activation of telomerase is achieved by multiple mechanisms. The expression of the gene encoding the catalytic subunit of telomerase (TERT) was directly upregulated by v-Rel. Moreover, the expression of v-Rel altered the ratio of alternatively spliced and full-length TERT transcripts in favor of the full-length forms. The activation of telomerase by v-Rel in lymphocytes was also accompanied by inactivation of nuclear inhibitors. The inhibition of telomerase activity in v-Rel-transformed cell lines led to apoptosis within 24 h. The expression of v-Rel in a macrophage cell line resulted in elevated levels of reactive oxygen species (ROS), increased telomerase activity, and increased sensitivity to telomerase inhibitors. In contrast, the ectopic expression of TERT decreased the extent of apoptosis induced by ROS. The activation of telomerase by v-Rel may, therefore, partially protect the transformed cells from apoptosis induced by ROS.
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Affiliation(s)
- Radmila Hrdlicková
- Section of Molecular Genetics and Microbiology, The University of Texas at Austin, Austin, TX 78712-1095, USA
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46
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Mukherjee Nee Chakraborty S, Ghosh U, Bhattacharyya NP, Bhattacharya RK, Dey S, Roy M. Curcumin-induced apoptosis in human leukemia cell HL-60 is associated with inhibition of telomerase activity. Mol Cell Biochem 2006; 297:31-9. [PMID: 17096185 DOI: 10.1007/s11010-006-9319-z] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2006] [Accepted: 08/25/2006] [Indexed: 12/01/2022]
Abstract
Curcumin (diferuloylmethane), a natural cancer chemopreventive compound, has been tested for its action in acute myeloblastic leukemia cell line HL-60. The results clearly show that curcumin induces apoptosis in these cells as evidenced by the release of cytochrome c from mitochondria to the cytosol and increase in the DNA content in sub G1 region as observed in FACS analysis. Apoptosis is apparently mediated by up-regulation of apoptotic gene bax and simultaneous down-regulation of anti-apoptotic gene bcl-2 followed by activation of caspases 3 and 8 and degradation of PARP. Telomerase, a reverse transcriptase, has been found to be activated in more than 80% of human cancers and, therefore, can be considered as a potential marker for tumorigenesis. Certain natural compounds have the potential of inhibiting telomerase activity leading to suppression of cell viability and induction of apoptosis. The present study shows that curcumin-induced apoptosis coincides with the inhibition of telomerase activity in a dose dependent manner.
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Affiliation(s)
- Sutapa Mukherjee Nee Chakraborty
- Department of Environmental Carcinogenesis & Toxicology, Chittaranjan National Cancer Institute, 37, S.P. Mukherjee Road, Kolkata 700 026, India
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47
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Li S, Ferguson MJ, Hawkins CJ, Smith C, Elwood NJ. Human telomerase reverse transcriptase protects hematopoietic progenitor TF-1 cells from death and quiescence induced by cytokine withdrawal. Leukemia 2006; 20:1270-8. [PMID: 16673017 DOI: 10.1038/sj.leu.2404251] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Telomerase is a complex ribonucleoprotein enzyme that exhibits elevated activity in the majority of cases of human leukemia. We have previously shown that retroviral expression of the catalytic subunit of telomerase, human telomerase reverse transcriptase (hTERT), in human cord blood CD34+ cells leads to an enhanced survival of mature hematopoietic cells. The mechanism for this pro-survival effect is not known. Here, we show that telomerase may play a role in leukemogenesis as a survival factor, independent of its role in maintaining telomere length. Retroviral expression of hTERT in the cytokine-dependent, human hematopoietic progenitor cell line, TF-1, resulted in the survival of cells following the withdrawal of cytokine, with protection from apoptosis, but did not promote unlimited replicative potential. This hTERT-mediated effect on cell survival does not involve Bcl-2 family members, results in accumulation of cells in G1 and appears to operate via autocrine expression of IL-3 and activation of the p53/p21 pathway. Survival in the absence of cytokine stimulation was also observed following retroviral expression of hTERT in normal cord blood CD34+ cells. This study demonstrates a novel pro-survival role for hTERT and may have important implications for the role of hTERT in the pathogenesis of leukemia and drug resistance.
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Affiliation(s)
- S Li
- Children's Cancer Centre, Murdoch Children's Research Institute, University of Melbourne, Parkville, Victoria, Australia
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48
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Li BL, Ma P, Song M, Song JY. The expression of apoptosis related genes in the process of canceration of atypical hyperplasia of mammary duct. Chin J Cancer Res 2006. [DOI: 10.1007/s11670-006-0045-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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49
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Peterson NC, Servinsky M. Characterization of the effects of Bcl-2 and Bcl-xl deletion mutant expression in cell lines used for antibody production. Hybridoma (Larchmt) 2006; 24:275-82. [PMID: 16332193 DOI: 10.1089/hyb.2005.24.275] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Strategies to maximize monoclonal antibody (MAb) yields by in vitro production methods entail that hybridoma cells be maintained at high density. Approaches to increase culture density and antibody yields from hybridomas by inhibiting apoptosis through over-expression of exogenous Bcl-2 family genes have produced variable results. In order to determine if expression of mutant forms of Bcl-2 and Bcl-xl could increase viable culture densities and batch MAb yields when compared to parental cell lines, recombinant delta loop deletion mutant of these apoptotic inhibitory genes were expressed in a myeloma and two hybridoma cell lines. Expression of either Bcl-2-delta or Bcl-xl-delta in P3x63Ag8.653 myeloma cells did not significantly increase viable cell densities in cultures over time. However, the rapid post-peak decline in viable cell density was significantly reduced in Bcl-xl-delta-expressing hybridoma cell lines 552 and 7.16.4 and in Bcl-2-expressing hybridoma 7.16.4. Significant increases in MAb yield were only observed in cultures of Bcl-xl-delta-expressing hybridoma 7.16.4. Annexin staining in hybridoma 7.16.4 confirmed that apoptosis was the primary means of cell death in this cell line, and expression of Bcl-2-delta and Bcl-xl-delta inhibited programmed cell death. These results suggest that cell viability in cultures can be improved by transfection and selection of hybridomas that express delta loop deletion mutant forms of Bcl-2 family genes; however, improvements in MAb yields are dependent upon the genetic background of each manipulated cell line.
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Affiliation(s)
- Norman C Peterson
- Department of Comparative Medicine, Johns Hopkins University, Baltimore, Maryland, USA.
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50
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Sikand K, Kaul D, Varma N. Receptor Ck-dependent signaling regulates hTERT gene transcription. BMC Cell Biol 2006; 7:2. [PMID: 16405739 PMCID: PMC1351175 DOI: 10.1186/1471-2121-7-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2005] [Accepted: 01/12/2006] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Available evidence suggests that the regulation of telomerase activity primarily depends on the transcriptional control of the human telomerase reverse transcriptase (hTERT) gene. Although several activators and repressors of hTERT gene transcription have been identified, the exact mechanism by which hTERT transcription is repressed in normal cells and activated in cancer cells remains largely unknown. In an attempt to identify possible novel mechanisms involved in the regulation of hTERT transcription, the present study examined the role of Receptor Ck, a cell surface receptor specific for cholesterol, in the transcription of hTERT gene in normal human peripheral blood mononuclear cells. RESULTS Activated Receptor Ck was found to down-regulate hTERT mRNA expression by repressing the transcription of c-myc gene. Receptor Ck-dependent signaling was also found to down-regulate the mRNA expression of the gene coding for the ligand inducible transcription factor, peroxisome proliferator-activated receptor gamma (PPARgamma). The ligand activation of PPARgamma resulted in the down-regulation of c-myc and hTERT mRNA expression. By using specific activator and inhibitor of protein kinase C (PKC), it was demonstrated that Receptor Ck dependent down-regulation of hTERT gene transcription involved inhibition of PKC. In addition, 25-hydroxycholesterol was found to contribute to the transcriptional regulation of hTERT gene. CONCLUSION Taken together, the findings of this study present evidence for a molecular link between cholesterol-activated Receptor Ck and hTERT transcription, and provide new insights into the regulation of hTERT expression in normal human peripheral blood mononuclear cells.
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Affiliation(s)
- Kavleen Sikand
- Department of Experimental Medicine & Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh – 160 012, India
| | - Deepak Kaul
- Department of Experimental Medicine & Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh – 160 012, India
| | - Neelam Varma
- Department of Haematology, Postgraduate Institute of Medical Education and Research, Chandigarh – 160 012, India
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