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Hlavca S, Chan WH, Engel RM, Abud HE. Clusterin: a marker and mediator of chemoresistance in colorectal cancer. Cancer Metastasis Rev 2024; 43:379-391. [PMID: 38319453 PMCID: PMC11015998 DOI: 10.1007/s10555-024-10173-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 01/24/2024] [Indexed: 02/07/2024]
Abstract
Intra-tumoural heterogeneity and cancer cell plasticity in colorectal cancer (CRC) have been key challenges to effective treatment for patients. It has been suggested that a subpopulation of LGR5-expressing cancer stem cells (CSCs) is responsible for driving tumour relapse and therapy resistance in CRC. However, studies have revealed that the LGR5+ve CSC population is highly sensitive to chemotherapy. It has been hypothesised that another subset of tumour cells can phenotypically revert to a stem-like state in response to chemotherapy treatment which replenishes the LGR5+ve CSC population and maintains tumour growth. Recently, a unique stem cell population marked by enriched clusterin (CLU) expression and termed the revival stem cell (RevSC) was identified in the regenerating murine intestine. This CLU-expressing cell population is quiescent during homeostasis but has the ability to survive and regenerate other stem cells upon injury. More recently, the CLU+ve signature has been implicated in several adverse outcomes in CRC, including chemotherapy resistance and poor patient survival; however, the mechanism behind this remains undetermined. In this review, we discuss recent insights on CLU in CRC and its roles in enhancing the plasticity of cells and further consider the implications of CLU as a prospective target for therapeutic intervention.
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Affiliation(s)
- Sara Hlavca
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC, 3800, Australia
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC, 3800, Australia
| | - Wing Hei Chan
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC, 3800, Australia
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC, 3800, Australia
| | - Rebekah M Engel
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC, 3800, Australia
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC, 3800, Australia
- Department of Surgery, Cabrini Monash University, Cabrini Hospital, Malvern, VIC, 3144, Australia
| | - Helen E Abud
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC, 3800, Australia.
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC, 3800, Australia.
- Department of Surgery, Cabrini Monash University, Cabrini Hospital, Malvern, VIC, 3144, Australia.
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2
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Praharaj PP, Patra S, Panigrahi DP, Patra SK, Bhutia SK. Clusterin as modulator of carcinogenesis: A potential avenue for targeted cancer therapy. Biochim Biophys Acta Rev Cancer 2020; 1875:188500. [PMID: 33385484 DOI: 10.1016/j.bbcan.2020.188500] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 12/14/2020] [Accepted: 12/24/2020] [Indexed: 12/30/2022]
Abstract
Clusterin (CLU) is an evolutionary conserved molecular chaperone present in different human tissues and fluids and established to be a significant cancer regulator. It controls several cancer-associated cellular events, including cancer cell proliferation, stemness, survival, metastasis, epithelial-mesenchymal transition, therapy resistance, and inhibition of programmed cell death to support cancer growth and recurrence. This multifunctional role of CLU makes it an ideal target for cancer control. More importantly, genetic and antisense-mediated (OGX-011) inhibition of CLU enhances the anticancer potential of different FDA-approved chemotherapeutic drugs at the clinical level, improving patient's survival. In this review, we have discussed the detailed mechanism of CLU-mediated modulation of different cancer-associated signaling pathways. We have also provided updated information on the current preclinical and clinical findings that drive trials in various cancer types for potential targeted cancer therapy.
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Affiliation(s)
- Prakash Priyadarshi Praharaj
- Cancer and Cell Death Laboratory, Department of Life Science, National Institute of Technology, Rourkela, 769008, Odisha, India
| | - Srimanta Patra
- Cancer and Cell Death Laboratory, Department of Life Science, National Institute of Technology, Rourkela, 769008, Odisha, India
| | - Debasna Pritimanjari Panigrahi
- Cancer and Cell Death Laboratory, Department of Life Science, National Institute of Technology, Rourkela, 769008, Odisha, India
| | - Samir Kumar Patra
- Epigenetics and Cancer Research Laboratory, Department of Life Science, National Institute of Technology, Rourkela, 769008, Odisha, India
| | - Sujit Kumar Bhutia
- Cancer and Cell Death Laboratory, Department of Life Science, National Institute of Technology, Rourkela, 769008, Odisha, India.
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Ma T, Guo R, Wang X, Shen WT, Zhu M, Jin YN, Xu HP. Lentiviral vector with a radiation-inducible promoter, carrying the ING4 gene, mediates radiosensitization controlled by radiotherapy in cervical cancer cells. Oncol Lett 2020; 21:67. [PMID: 33365078 PMCID: PMC7716713 DOI: 10.3892/ol.2020.12328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 10/19/2020] [Indexed: 12/24/2022] Open
Abstract
The presence of hypoxia in solid tumors is considered one of the major factors that contribute to radiation resistance. The aim of the present study was to establish a therapeutic system, which can be controlled by radiation itself, to enhance radiosensitivity. For this purpose, a lentiviral gene therapy vector containing the human inhibitor of growth 4 (ING4) and its upstream promoter, human early growth response factor-1 (EGR1), which possesses the radiation-inducible characteristics to activate the transcription of its downstream genes, was constructed. Downstream fluorescence proteins were investigated to ensure that the EGR1 promoter was induced by irradiation. Furthermore, ING4 open reading frame (ORF) expression was detected by western blotting. The cell cycle was analyzed by fluorescence-activated cell sorting analysis 48 h after the cells were exposed to X-rays ranging between 0 and 8 Gy. In cells stably and transiently transfected with reporter plasmids, the EGR1-driver gene was sensitive to ionizing irradiation. Furthermore, irradiation-induced ING4 gene expression was observed. The enhanced ING4 expression increased the number of cells in the G2/M phase and decreased the proportion of cells in the G1/S phase. Therefore, ING4 expression inhibited cell proliferation and was associated with less colonies being formed. Furthermore, ING4 suppressed hypoxia-inducible factor 1α expression under hypoxic conditions and promoted cell apoptosis. Overall, these results revealed that combining the EGR1 promoter and ING4 ORF using a lentivirus system may be a promising therapeutic strategy with which to enhance radiosensitivity controlled by radiation. However, further studies using in vivo models are required to confirm these findings.
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Affiliation(s)
- Tao Ma
- Department of Radiation Oncology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, P.R. China
| | - Rui Guo
- Department of Nuclear Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, P.R. China
| | - Xi Wang
- Department of Neurology, Hackensack Meridian Health JFK Medical Center, Edison, NJ 08820, USA
| | - Wen-Tong Shen
- Department of Radiation Oncology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, P.R. China
| | - Min Zhu
- Department of Radiation Oncology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, P.R. China
| | - Ye-Ning Jin
- Department of Radiation Oncology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, P.R. China
| | - Hao-Ping Xu
- Department of Radiation Oncology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, P.R. China
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Foster EM, Dangla-Valls A, Lovestone S, Ribe EM, Buckley NJ. Clusterin in Alzheimer's Disease: Mechanisms, Genetics, and Lessons From Other Pathologies. Front Neurosci 2019; 13:164. [PMID: 30872998 PMCID: PMC6403191 DOI: 10.3389/fnins.2019.00164] [Citation(s) in RCA: 203] [Impact Index Per Article: 40.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 02/12/2019] [Indexed: 01/10/2023] Open
Abstract
Clusterin (CLU) or APOJ is a multifunctional glycoprotein that has been implicated in several physiological and pathological states, including Alzheimer's disease (AD). With a prominent extracellular chaperone function, additional roles have been discussed for clusterin, including lipid transport and immune modulation, and it is involved in pathways common to several diseases such as cell death and survival, oxidative stress, and proteotoxic stress. Although clusterin is normally a secreted protein, it has also been found intracellularly under certain stress conditions. Multiple hypotheses have been proposed regarding the origin of intracellular clusterin, including specific biogenic processes leading to alternative transcripts and protein isoforms, but these lines of research are incomplete and contradictory. Current consensus is that intracellular clusterin is most likely to have exited the secretory pathway at some point or to have re-entered the cell after secretion. Clusterin's relationship with amyloid beta (Aβ) has been of great interest to the AD field, including clusterin's apparent role in altering Aβ aggregation and/or clearance. Additionally, clusterin has been more recently identified as a mediator of Aβ toxicity, as evidenced by the neuroprotective effect of CLU knockdown and knockout in rodent and human iPSC-derived neurons. CLU is also the third most significant genetic risk factor for late onset AD and several variants have been identified in CLU. Although the exact contribution of these variants to altered AD risk is unclear, some have been linked to altered CLU expression at both mRNA and protein levels, altered cognitive and memory function, and altered brain structure. The apparent complexity of clusterin's biogenesis, the lack of clarity over the origin of the intracellular clusterin species, and the number of pathophysiological functions attributed to clusterin have all contributed to the challenge of understanding the role of clusterin in AD pathophysiology. Here, we highlight clusterin's relevance to AD by discussing the evidence linking clusterin to AD, as well as drawing parallels on how the role of clusterin in other diseases and pathways may help us understand its biological function(s) in association with AD.
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Affiliation(s)
| | | | | | | | - Noel J. Buckley
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
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Rohne P, Prochnow H, Koch-Brandt C. The CLU-files: disentanglement of a mystery. Biomol Concepts 2016; 7:1-15. [PMID: 26673020 DOI: 10.1515/bmc-2015-0026] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 11/05/2015] [Indexed: 01/03/2023] Open
Abstract
The multifaceted protein clusterin (CLU) has been challenging researchers for more than 35 years. The characterization of CLU as a molecular chaperone was one of the major breakthroughs in CLU research. Today, secretory clusterin (sCLU), also known as apolipoprotein J (apoJ), is considered one of the most important extracellular chaperones ever found. It is involved in a broad range of physiological and pathophysiological functions, where it exerts a cytoprotective role. Descriptions of various forms of intracellular CLU have led to further and even contradictory functions. To untangle the current state of knowledge of CLU, this review will combine old views in the field, with new discoveries to highlight the nature and function of this fascinating protein(s). In this review, we further describe the expression and subcellular location of various CLU forms. Moreover, we discuss recent insights into the structure of CLU and assess how structural properties as well as the redox environment determine the chaperone activity of CLU. Eventually, the review connects the biochemistry and molecular cell biology of CLU with medical aspects, to formulate a hypothesis of a CLU function in health and disease.
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Wang J, Li Y, Liu Y, Li Y, Gong S, Fang F, Wang Z. Overexpression of truncated AIF regulated by Egr1 promoter radiation-induced apoptosis on MCF-7 cells. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2015; 54:413-421. [PMID: 26514806 DOI: 10.1007/s00411-015-0619-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 08/23/2015] [Indexed: 06/05/2023]
Abstract
It has been demonstrated that gene-radiotherapy can improve the radiotherapy by selectively increasing cells' response to ionizing radiation. Apoptosis-inducing factor (AIF) is a mitochondrial flavoprotein, and its C-terminal domain is responsible for the proapoptotic activity. In the present study, we overexpressed truncated AIF on MCF-7 cells by transfection of pcDNA3.1-tAIF (pc-tAIF) and pcDNA3.1-Egr1-tAIF (pc-Egr1-tAIF) plasmids. After MCF-7-tAIF cells were exposed to X-rays, the AIF and tAIF expressions, cell proliferation, apoptosis, cell cycle invasion, cytochrome c (Cyt c) release and activation of caspase-9 were measured by using Western blot, MTT assay, flow cytometry and Matrigel transwell assay, respectively. Our results showed that tAIF expression increased on time- and dose-dependent manners. Both tAIF and radiation can synergistically enhance the apoptosis, cell proliferation inhibition, cell cycle arrest and cell-invasive inhibition. In addition, tAIF overexpression and irradiation increased Cyt c release. However, only irradiation increased caspase-9 activation. Our studies indicated that tAIF overexpression might enhance apoptosis induced by radiation in MCF-7 cells.
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Affiliation(s)
- Jianfeng Wang
- Department of Radiotherapy, China-Japan Union Hospital, Jilin University, Changchun, Jilin Province, People's Republic of China
- Key Laboratory of Radiobiology, Ministry of Health, School of Public Health, Jilin University, Changchun, Jilin Province, People's Republic of China
| | - Yana Li
- Department of Ophthalmology and Otolaryngology, The Children's Hospital of Changchun, Changchun, Jilin Province, People's Republic of China
| | - Yang Liu
- Key Laboratory of Radiobiology, Ministry of Health, School of Public Health, Jilin University, Changchun, Jilin Province, People's Republic of China
| | - Yanbo Li
- Key Laboratory of Radiobiology, Ministry of Health, School of Public Health, Jilin University, Changchun, Jilin Province, People's Republic of China
- School of Public Health and Family Medicine, Capital Medical University, Beijing, People's Republic of China
| | - Shouliang Gong
- Key Laboratory of Radiobiology, Ministry of Health, School of Public Health, Jilin University, Changchun, Jilin Province, People's Republic of China
| | - Fang Fang
- Key Laboratory of Radiobiology, Ministry of Health, School of Public Health, Jilin University, Changchun, Jilin Province, People's Republic of China.
- Department of Nutrition and Food Hygiene, School of Public Health, Jilin University, Changchun, Jilin Province, People's Republic of China.
| | - Zhicheng Wang
- Key Laboratory of Radiobiology, Ministry of Health, School of Public Health, Jilin University, Changchun, Jilin Province, People's Republic of China.
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Bazan JG, Chang P, Balog R, D'Andrea A, Shaler T, Lin H, Lee S, Harrison T, Shura L, Schoen L, Knox SJ, Cooper DE. Novel Human Radiation Exposure Biomarker Panel Applicable for Population Triage. Int J Radiat Oncol Biol Phys 2014; 90:612-9. [DOI: 10.1016/j.ijrobp.2014.05.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 05/22/2014] [Accepted: 05/27/2014] [Indexed: 11/30/2022]
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8
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Li CF, Chen LB, Li DD, Yang L, Zhang BG, Jin JP, Zhang Y, Zhang B. Dual‑sensitive HRE/Egr1 promoter regulates Smac overexpression and enhances radiation‑induced A549 human lung adenocarcinoma cell death under hypoxia. Mol Med Rep 2014; 10:1108-16. [PMID: 24842518 DOI: 10.3892/mmr.2014.2233] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 04/04/2014] [Indexed: 11/05/2022] Open
Abstract
The aim of this study was to construct an expression vector carrying the hypoxia/radiation dual‑sensitive chimeric hypoxia response element (HRE)/early growth response 1 (Egr‑1) promoter in order to overexpress the therapeutic second mitochondria‑derived activator of caspases (Smac). Using this expression vector, the present study aimed to explore the molecular mechanism underlying radiotherapy‑induced A549 human lung adenocarcinoma cell death and apoptosis under hypoxia. The plasmids, pcDNA3.1‑Egr1‑Smac (pE‑Smac) and pcDNA3.1‑HRE/Egr-1‑Smac (pH/E‑Smac), were constructed and transfected into A549 human lung adenocarcinoma cells using the liposome method. CoCl2 was used to chemically simulate hypoxia, followed by the administration of 2 Gy X‑ray irradiation. An MTT assay was performed to detect cell proliferation and an Annexin V‑fluorescein isothiocyanate apoptosis detection kit was used to detect apoptosis. Quantitative polymerase chain reaction and western blot analyses were used for the detection of mRNA and protein expression, respectively. Infection with the pE‑Smac and pH/E‑Smac plasmids in combination with radiation and/or hypoxia was observed to enhance the expression of Smac. Furthermore, Smac overexpression was found to enhance the radiation‑induced inhibition of cell proliferation and promotion of cycle arrest and apoptosis. The cytochrome c/caspase‑9/caspase‑3 pathway was identified to be involved in this regulation of apoptosis. Plasmid infection in combination with X‑ray irradiation was found to markedly induce cell death under hypoxia. In conclusion, the hypoxia/radiation dual‑sensitive chimeric HRE/Egr‑1 promoter was observed to enhance the expression of the therapeutic Smac, as well as enhance the radiation‑induced inhibition of cell proliferation and promotion of cycle arrest and apoptosis under hypoxia. This apoptosis was found to involve the mitochondrial pathway.
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Affiliation(s)
- Chang-Feng Li
- Endoscopy Center, China‑Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - Li-Bo Chen
- Endoscopy Center, China‑Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - Dan-Dan Li
- Endoscopy Center, China‑Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - Lei Yang
- Endoscopy Center, China‑Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - Bao-Gang Zhang
- Endoscopy Center, China‑Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - Jing-Peng Jin
- Endoscopy Center, China‑Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - Ying Zhang
- Endoscopy Center, China‑Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - Bin Zhang
- Endoscopy Center, China‑Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
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Malla RR, Gopinath S, Alapati K, Gorantla B, Gondi CS, Rao JS. uPAR and cathepsin B inhibition enhanced radiation-induced apoptosis in gliomainitiating cells. Neuro Oncol 2012; 14:745-60. [PMID: 22573309 DOI: 10.1093/neuonc/nos088] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Glioblastomas present as diffuse tumors with invasion into normal brain tissue and frequently recur or progress after radiation as focal masses because of glioma-initiating cells. The role of the urokinase-type plasminogen activator receptor (uPAR) and cathepsin B in stem-like phenotype has been extensively studied in several solid tumors. In the present study, we demonstrated that selection of glioma-initiating cells using CD133 expression leads to a specific enrichment of CD133(+) cells in both U87 and 4910 cells. In addition, CD133(+) cells exhibited a considerable amount of other stem cell markers, such as Nestin and Sox-2. Radiation treatment significantly enhanced uPAR and cathepsin B levels in glioma-initiating cells. To downregulate radiation-induced uPAR and cathepsin B expression, we used a bicistronic shRNA construct that simultaneously targets both uPAR and cathepsin B (pCU). Downregulation of uPAR and cathepsin B using pCU decreased radiation-enhanced uPAR and cathepsin B levels and caused DNA damage-induced apoptosis in glioma cell lines and glioma-initiating cells. The most striking finding of this study is that knockdown of uPAR and cathepsin B inhibited ongoing transcription by suppressing BrUTP incorporation at γH2AX foci. In addition, uPAR and cathepsin B gene silencing inversely regulated survivin and H2AX expression in both glioma cells and glioma-initiating cells. Pretreatment with pCU reduced radiation-enhanced expression of uPAR, cathepsin B, and survivin and enhanced DNA damage in pre-established glioma in nude mice. Taken together, our in vitro and in vivo findings suggest that uPAR and cathepsin B inhibition might serve as an adjunct to radiation therapy to target glioma-initiating cells and, therefore, for the treatment of glioma.
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Affiliation(s)
- Rama Rao Malla
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, One Illini Drive, Peoria, IL 61605, USA
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Sudo H, Tsuji AB, Sugyo A, Ogawa Y, Sagara M, Saga T. ZDHHC8 knockdown enhances radiosensitivity and suppresses tumor growth in a mesothelioma mouse model. Cancer Sci 2011; 103:203-9. [PMID: 22017350 DOI: 10.1111/j.1349-7006.2011.02126.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mesothelioma is an aggressive tumor caused by asbestos exposure, the incidence of which is predicted to increase globally. The prognosis of patients with mesothelioma undergoing conventional therapy is poor. Radiation therapy for mesothelioma is of limited use because of the intrinsic radioresistance of tumor cells compared with surrounding normal tissue. Thus, a novel molecular-targeted radiosensitizing agent that enhances the radiosensitivity of mesothelioma cells is required to improve the therapeutic efficacy of radiation therapy. ZDHHC8 knockdown reduces cell survival and induces an impaired G(2) /M checkpoint after X-irradiation in HEK293 cells. In the present study, we further analyzed the effect of the combination of ZDHHC8 knockdown and X-irradiation and assessed its therapeutic efficacy in mesothelioma models. SiRNA-induced ZDHHC8 knockdown in 211H and H2052 mesothelioma cells significantly reduced cell survival after X-irradiation. In 211H cells treated with ZDHHC8 siRNA and X-irradiation, the G(2) /M checkpoint was impaired and there was an increase in the number of cells with micronuclei, as well as apoptotic cells, in vitro. In 211H tumor-bearing mice, ZDHHC8 siRNA and X-irradiation significantly suppressed tumor growth, whereas ZDHHC8 siRNA alone did not. Immunohistochemical analysis showed decreased cell proliferation and induction of apoptosis in tumors treated with ZDHHC8 siRNA and X-irradiation, but not with ZDHHC8 siRNA alone. These results suggest that ZDHHC8 knockdown with X-irradiation induces chromosomal instability and apoptosis through the impaired G(2) /M checkpoint. In conclusion, the combination of ZDHHC8 siRNA and X-irradiation has the potential to improve the therapeutic efficacy of radiation therapy for malignant mesothelioma.
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Affiliation(s)
- Hitomi Sudo
- Diagnostic Imaging Group, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.
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Mao XW, Mekonnen T, Kennedy AR, Gridley DS. Differential expression of oxidative stress and extracellular matrix remodeling genes in low- or high-dose-rate photon-irradiated skin. Radiat Res 2011; 176:187-97. [PMID: 21574862 DOI: 10.1667/rr2493.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Changes in the expression of genes implicated in oxidative stress and in extracellular matrix (ECM) remodeling and selected protein expression profiles in mouse skin were examined after exposure to low-dose-rate or high-dose-rate photon irradiation. ICR mice received whole-body γ rays to total doses of 0, 0.25, 0.5 and 1 Gy at dose rates of 50 cGy/h or 50 cGy/min. Skin tissues were harvested for characterization at 4 h after irradiation. For oxidative stress after low-dose-rate exposure, 0.25, 0.5 and 1 Gy significantly altered 27, 23 and 25 genes, respectively, among 84 genes assessed (P < 0.05). At doses as low as 0.25 Gy, many genes responsible for regulating the production of reactive oxygen species (ROS) were significantly altered, with changes >2-fold compared to 0 Gy. For an ECM profile, 18-20 out of 84 genes were significantly up- or downregulated after low-dose-rate exposure. After high-dose-rate irradiation, of 84 genes associated with oxidative stress, 16, 22 and 22 genes were significantly affected after 0.25, 0.5 and 1 Gy, respectively. Compared to low-dose-rate radiation, high-dose-rate exposure resulted in different ECM gene expression profiles. The most striking changes after low-dose-rate or high-dose-rate exposure on ECM profiles were on genes encoding matrix metalloproteinases (MMPs), e.g., Mmp2 and Mmp15 for low dose rate and Mmp9 and Mmp11 for high dose rate. Immunostaining for MMP-2 and MMP-9 proteins showed radiation dose rate-dependent differences. These data revealed that exposure to low total doses with low-dose-rate or high-dose-rate photon radiation induced oxidative stress and ECM-associated alterations in gene expression profiles. The expression of many genes was differentially regulated by different total dose and/or dose-rate regimens.
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Affiliation(s)
- Xiao Wen Mao
- Department of Radiation Medicine, Radiation Research Laboratories, Loma Linda University Medical Center, Loma Linda, California 92354, USA.
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Rossi A, Schenone S, Angelucci A, Cozzi M, Caracciolo V, Pentimalli F, Puca A, Pucci B, La Montagna R, Bologna M, Botta M, Giordano A. New pyrazolo-[3,4-d]-pyrimidine derivative Src kinase inhibitors lead to cell cycle arrest and tumor growth reduction of human medulloblastoma cells. FASEB J 2010; 24:2881-92. [PMID: 20354138 DOI: 10.1096/fj.09-148593] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Medulloblastoma is the most common malignant brain tumor in children, and despite improvements in the overall survival rate, it still lacks an effective treatment. Src plays an important role in cancer, and recently high Src activity was documented in medulloblastoma. In this report, we examined the effects of novel pyrazolo-[3,4-d]-pyrimidine derivative Src inhibitors in medulloblastoma. By MTS assay, we showed that the pyrimidine derivatives indicated as S7, S29, and SI163 greatly reduce the growth rate of medulloblastoma cells by inhibiting Src phosphorylation, compared with HT22 non-neoplastic nerve cells. These compounds also halt cells in the G(2)/M phase, and this effect likely occurs through the regulation of cdc2 and CDC25C phosphorylation, as shown by Western blot. Moreover, the exposure to pyrimidine derivatives induces apoptosis, assayed by the supravital propidium iodide assay, through modulation of the apoptotic proteins Bax and Bcl2, and inhibits tumor growth in vivo in a mouse model. Notably, S7, S29, and SI163 show major inhibitory effects on medulloblastoma cell growth compared with the chemotherapeutic agents cisplatin and etoposide. In conclusion, our results suggest that S7, S29, and SI163 could be novel attractive candidates for the treatment of medulloblastoma or tumors characterized by high Src activity.
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Affiliation(s)
- Alessandra Rossi
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, 1900 North 12th St., Philadelphia, PA 19122, USA
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13
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Flanagan L, Whyte L, Chatterjee N, Tenniswood M. Effects of clusterin over-expression on metastatic progression and therapy in breast cancer. BMC Cancer 2010; 10:107. [PMID: 20307318 PMCID: PMC2856549 DOI: 10.1186/1471-2407-10-107] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2009] [Accepted: 03/22/2010] [Indexed: 12/22/2022] Open
Abstract
Background Clusterin is a secreted glycoprotein that is upregulated in a variety of cell lines in response to stress, and enhances cell survival. A second nuclear isoform of clusterin that is associated with cell death has also been identified. The aim of this study was to determine the role(s) of the secretory isoform in breast tumor progression and metastasis. Methods To investigate the role of secretory clusterin in the biology of breast cancer tumor growth and resistance to therapy we have engineered an MCF-7 cell line (MCF-7CLU) that over-expresses clusterin. We have measured the in vitro effects of clusterin over-expression on cell cycle, cell death, and sensitivity to TNFalpha and tamoxifen. Using an orthotopic model of breast cancer, we have also determined the effects of over-expression of clusterin on tumor growth and metastatic progression. Results In vitro, over-expression of secretory clusterin alters the cell cycle kinetics and decreases the rate of cell death, resulting in the enhancement of cell growth. Over-expression of secretory clusterin also blocks the TNFalpha-mediated induction of p21 and abrogates the cleavage of Bax to t-Bax, rendering the MCF-7CLU cells significantly more resistant to the cytokine than the parental cells. Orthotopic primary tumors derived from MCF-7CLU cells grow significantly more rapidly than tumors derived from parental MCF-7 cells and, unlike the parental cells, metastasize frequently to the lungs. Conclusions These data suggest that secretory clusterin, which is frequently up-regulated in breast cancers by common therapies, including anti-estrogens, may play a significant role in tumor growth, metastatic progression and subsequent drug resistance in surviving cells.
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Affiliation(s)
- Louise Flanagan
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
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Abstract
The possible biological role played by Clusterin (CLU) has been puzzling researchers for a long time since its first discovery and characterization. CLU has been often described as an "enigmatic" gene, a clear indication that too many aspects of this issue have been obscure or difficult to interpret for long. The good news is that this is certainly no longer true. Since the beginning, CLU was believed to play important roles in nearly all most important biological phenomena. The diversity, sometime the contradictions, of its biological action is now likely explained by the existence of different protein products all generated by the same single copy CLU gene. The relatively recent discovery that CLU can be retained inside the cell and targeted to many intracellular sites and organelles, including the nucleus, provided us a very different view from that solely deriving from its possible role in the outer cellular environment. In particular, nuclear localization of CLU (nCLU) was found to trigger cell death in many systems. In this chapter, a critical review of previous work will enable us to reinterpret old data and observations in the attempt to progressively unravelling the CLU "enigma" by considering its localization inside and outside the cell. The final picture would supposedly reconciliate different or alternative hypothesis. Starting with an "historical" approach demonstrating that nCLU was right under our eyes since the beginning, up to the more recent contributions we will describe which stimuli would inhibit secretion and maturation of CLU leading at least one protein product to target the nucleus and kill the cell. A better understanding of this complex issue is not an easy work, considering the thoughtfulness in reviewing the existing literature and the known controversial reports. We hope that the information contained in this article will be useful for the reader to enlighten this field.
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Affiliation(s)
- Saverio Bettuzzi
- Dipartimento di Medicina Sperimentale, Sezione di Biochimica, Biochimica Clinica e Biochimica dell'Esercizio Fisico, Parma, Italy
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Panico F, Rizzi F, Fabbri LM, Bettuzzi S, Luppi F. Clusterin (CLU) and lung cancer. Adv Cancer Res 2010; 105:63-76. [PMID: 19879423 DOI: 10.1016/s0065-230x(09)05004-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Lung cancer is the leading cause of cancer-related mortality. It is categorized into two histological groups that have distinct clinical behaviors, the nonsmall cell lung cancers (NSCLC) and the small cell lung cancer (SCLC). When identified at an early stage, NSCLC is treated by surgical resection. However, patients who undergo surgical resection still have a relative low survival rate, primarily for tumor recurrence. Unfortunately, advances in cytotoxic therapy have reached a plateau and new approaches to treatment are needed together with new and better parameters for more accurate prediction of the outcome and more precise indication of the efficacy of the treatment. Several in vitro studies have examined the role of Clusterin (CLU) in carcinogenesis, lung cancer progression, and response to chemo- and radiotherapy. Studies performed in lung cancer cell lines and animal models showed that CLU is upregulated after exposure to chemo- and radiotherapy. A potential role proposed for the protein is cytoprotective. In vitro, CLU silencing by antisense oligonucleotides (ASO) and small-interfering RNAs (siRNA) directed against CLU mRNA in CLU-rich lung cancer cell lines sensitized cells to chemotherapy and radiotherapy and decreased their metastatic potential. In vivo, a recent work analyzed the prognostic role of CLU in NSCLC, showing that CLU-positive patients with lung cancer had a better overall survival and disease-free survival than those with CLU-negative tumors. These data are contradictory to the promising in vitro results. From the results of these studies we may hypothesize that in early-stage lung cancers CLU represents a positive biomarker correlating with better overall survival. In advanced patients, already treated with chemo- and radiotherapy, the induction of CLU may confer resistance to the treatments. However, many studies are needed to better understand the role of CLU in early-stage and advanced lung cancers with the aim to discriminate patients and specific local conditions that could benefit for a CLU knocking down treatment.
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Affiliation(s)
- F Panico
- Department of Oncology, Hematology and Respiratory Diseases, Section of Respiratory Diseases, University of Modena and Reggio Emilia, 41100 Modena, Italy
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Filipenko EA, Deineko EV, Shumnyi VK. Specific features of T-DNA insertion regions in transgenic plants. RUSS J GENET+ 2009. [DOI: 10.1134/s1022795409110040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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Postiglione I, Chiaviello A, Palumbo G. Twilight effects of low doses of ionizing radiation on cellular systems: a bird's eye view on current concepts and research. Med Oncol 2009; 27:495-509. [PMID: 19504191 DOI: 10.1007/s12032-009-9241-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Accepted: 05/22/2009] [Indexed: 01/10/2023]
Abstract
The debate about the health risks from low doses of radiation is vigorous and often acrimonious since many years and does not appear to weaken. Being far from completeness, this review presents only a bird's eye view on current concepts and research in the field. It is organized and divided in two parts. The first is dedicated to molecular responses determined by radiation-induced DNA ruptures. It focuses its attention on molecular pathways that are activated by ATM and tries to describe the variegated functions and specific roles of Chk2 and p53 and other proteins in sensing, promoting and executing DNA repair. The second part is more concerned with the risk associated with exposure to low dose radiation and possible effects that the radiation-affected cell may undergo. These effects include induction of apoptosis and mitotic catastrophe, bystander effect and genomic instability, senescence and hormetic response. Current hypotheses and research on these issues are briefly discussed.
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Affiliation(s)
- Ilaria Postiglione
- Dipartimento di Biologia e Patologia Cellulare e Molecolare, L Califano and IEOS/CNR, University FEDERICO II, Via Sergio Pansini 5, 80131 Naples, Italy
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18
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Kovalchuk I, Boyko A. Improvement of Plant Transformation. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2009. [DOI: 10.1201/9781420077070.ch7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Chetty C, Bhoopathi P, Rao JS, Lakka SS. Inhibition of matrix metalloproteinase-2 enhances radiosensitivity by abrogating radiation-induced FoxM1-mediated G2/M arrest in A549 lung cancer cells. Int J Cancer 2009; 124:2468-77. [PMID: 19165865 DOI: 10.1002/ijc.24209] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Matrix metalloproteinase-2 (MMP-2), is known to degrade the collagen IV, plays a role in radiation-induced lung injury. We therefore investigated the antitumor effects of combining MMP-2 inhibition using an adenovirus expressing siRNA against MMP-2 (Ad-MMP-2-Si) with radiation therapy (IR) on A549 lung cancer cells in vitro and in vivo. IR increased MMP-2 mRNA, protein and activity in lung cancer cells. MMP-2 inhibition along with IR enhanced radiosensitivity as determined by clonogenic assay, flow cytometry and TUNEL assay. We show that MMP-2 inhibition prior to irradiation reduced p53 phosphorylation, with a corresponding reduction in the expression of the p53 downstream target gene p21(Cip1/Waf1). Irradiated tumor cells induced the FoxM1-mediated DNA repair gene, XRCC1 and Checkpoint kinases 2/1, which were abrogated with combined treatment of Ad-MMP-2-Si and IR. Further, the combination of Ad-MMP-2-Si with radiotherapy significantly increased antitumor efficacy in vivo compared to either agent alone. Indeed, histological analysis of tumor sections collected from the combination group revealed more apoptotic cells. These studies suggest that MMP-2 inhibition in combination with radiotherapy abrogates G2 cell cycle arrest leading to apoptosis and provide evidence of the antitumor efficacy of combining MMP-2 inhibition with irradiation as a new therapeutic strategy for the effective treatment of NSCLC patients.
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Affiliation(s)
- Chandramu Chetty
- Program of Cancer Biology, Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, One Illini Drive, Peoria, IL 61605, USA
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Lage C, Alencar TD, Vidal LS, Wilmart-Gonçalves TC, Borba-Santos L, Alves AM, Paula-Pereira-Jr MV, Felicio DL, Irineu R, Cardoso JS, Leitão AC. Targeting DNA in therapies: using damages to design strategies on cell sensitisation. ACTA ACUST UNITED AC 2008. [DOI: 10.1088/1742-6596/101/1/012013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Söderlund K, Skoog L, Fornander T, Askmalm MS. The BRCA1/BRCA2/Rad51 complex is a prognostic and predictive factor in early breast cancer. Radiother Oncol 2007; 84:242-51. [PMID: 17707537 DOI: 10.1016/j.radonc.2007.06.012] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2007] [Revised: 05/03/2007] [Accepted: 06/27/2007] [Indexed: 11/22/2022]
Abstract
BACKGROUND AND PURPOSE The breast cancer susceptibility genes BRCA1 and BRCA2 interact with Rad51, one of the central components in the homologous recombination repair pathway. This study evaluates the prognostic and predictive role of BRCA1, BRCA2 and Rad51, individually and as a complex, in breast cancer. MATERIALS AND METHODS Expression of BRCA1, BRCA2 and Rad51 was investigated using immunohistochemistry in tumours from 224 women with early breast cancer, who were randomised to receive postoperative radiotherapy or adjuvant chemotherapy (CMF). RESULTS Fifty-three percent (112/212) of the tumours had reduced expression of the BRCA1/BRCA2/Rad51 complex. Low expression correlated to high histologic grade (p=0.05). Patients with low expression of the complex developed significantly more local recurrences as compared to patients with high expression (RR=3.20, 95% CI 1.48-6.88, p=0.003). Expression of the BRCA1/BRCA2/Rad51 complex was an independent prognostic factor in multivariate analysis (p=0.03). Patients with low expression of the complex responded well to radiotherapy (RR=0.31, 95% CI 0.14-0.70, p=0.005), whereas patients with high expression had few local recurrences and no additional benefit from radiotherapy (RR=1.08, 95% CI 0.40-2.90, p=0.88). CONCLUSIONS Low expression of the BRCA1/BRCA2/Rad51 complex is a marker of poor prognosis, but predicts good response to radiotherapy in patients with early breast cancer.
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Affiliation(s)
- Karin Söderlund
- Department of Biomedicine and Surgery, Linköping University, Linköping, Sweden.
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23
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Söderlund K, Stål O, Skoog L, Rutqvist LE, Nordenskjöld B, Askmalm MS. Intact Mre11/Rad50/Nbs1 complex predicts good response to radiotherapy in early breast cancer. Int J Radiat Oncol Biol Phys 2007; 68:50-8. [PMID: 17337132 DOI: 10.1016/j.ijrobp.2006.12.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 12/07/2006] [Accepted: 12/08/2006] [Indexed: 11/18/2022]
Abstract
PURPOSE To investigate the expression and predictive role of the Mre11/Rad50/Nbs1 (MRN) complex and the ataxia-telangiectasia mutated protein (ATM) for the outcome of radiotherapy in breast cancer patients. METHODS AND MATERIALS The protein expression of ATM and the DNA repair proteins in the MRN complex were investigated using immunohistochemistry in tumors from 224 women with early breast cancer, who were randomized to receive postoperative radiotherapy or adjuvant chemotherapy. RESULTS Compared with normal breast tissue, the staining intensity of Mre11, Rad50, Nbs1, and ATM was reduced in a majority of the tumors. Weak expression of the MRN complex was correlated with high histologic grade and estrogen receptor negativity (p = 0.01 and p = 0.0001, respectively). Radiotherapy significantly reduced the risk of local recurrence as compared with chemotherapy (p = 0.04). The greatest benefit of radiotherapy was seen in patients with moderate/strong expression of the MRN complex (relative risk = 0.27, 95% confidence interval = 0.098-0.72, p = 0.009), whereas patients with negative/weak MRN expression had no benefit of radiotherapy compared with adjuvant chemotherapy. These results suggest that an intact MRN complex is important for the tumor cell eradicating effect of radiotherapy. CONCLUSIONS Reduced expression of the MRN complex predicts a poor effect of radiotherapy in patients with early breast cancer.
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Affiliation(s)
- Karin Söderlund
- Department of Biomedicine and Surgery, Division of Oncology, Linköping University, Linköping, Sweden.
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24
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Merolla F, Pentimalli F, Pacelli R, Vecchio G, Fusco A, Grieco M, Celetti A. Involvement of H4(D10S170) protein in ATM-dependent response to DNA damage. Oncogene 2007; 26:6167-75. [PMID: 17420723 DOI: 10.1038/sj.onc.1210446] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
H4(D10S170) gene has been identified upon its frequent rearrangement with RET in papillary thyroid tumours (RET/PTC1). The kinase ataxia telangectasia mutated (ATM) phosphorylates a limited number of downstream protein targets in response to DNA damage. We investigated the potential role of H4(D10S170) in DNA damage signaling pathways. We found that in cells treated with etoposide or ionizing radiation (IR), H4(D10S170) underwent ATM-mediated phosphorylation at Thr 434, stabilizing nuclear H4. In ataxia telangectasia cells (A-T), endogenous H4(D10S170) was localized to cytoplasm and was excluded from the nucleus. Moreover, H4(D10S170) was not phosphorylated in ATM-deficient lymphoblasts after ionizing irradiation. Inhibition of ATM kinase interfered with H4(D10S170) apoptotic activity, and expression of H4 with threonine 434 mutated in Alanine, H4(T434A), protected the cells from genotoxic stress-induced apoptosis. Most importantly, after exposure to IR we found that silencing of H4(D10S170) in mammalian cells increased cell survival, as shown by clonogenic assay, allows for DNA synthesis as evaluated by bromodeoxyuridine incorporation and permits cells to progress into mitosis as demonstrated by phosphorylation on Histone H3. Our results suggest that H4(D10S170) is involved in cellular response to DNA damage ATM-mediated, and that the impairment of H4(D10S170) gene function might have a role in thyroid carcinogenesis.
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Affiliation(s)
- F Merolla
- Dipartimento di Biologia e Patologia Cellulare e Molecolare, University 'Federico II', Naples, Italy
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Lacroix B, Li J, Tzfira T, Citovsky V. Will you let me use your nucleus? How Agrobacterium gets its T-DNA expressed in the host plant cell. Can J Physiol Pharmacol 2006; 84:333-45. [PMID: 16902581 DOI: 10.1139/y05-108] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Agrobacterium is the only known bacterium capable of natural DNA transfer into a eukaryotic host. The genes transferred to host plants are contained on a T-DNA (transferred DNA) molecule, the transfer of which begins with its translocation, along with several effector proteins, from the bacterial cell to the host-cell cytoplasm. In the host cytoplasm, the T-complex is formed from a single-stranded copy of the T-DNA (T-strand) associated with several bacterial and host proteins and it is imported into the host nucleus via interactions with the host nuclear import machinery. Once inside the nucleus, the T-complex is most likely directed to the host genome by associating with histones. Finally, the chromatin-associated T-complex is uncoated from its escorting proteins prior to the conversion of the T-strand to a double-stranded form and its integration into the host genome.
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Affiliation(s)
- Benoît Lacroix
- Department of Biochemistry and Cell Biology, State University of NY, Stony Brook, 11794-5212, USA.
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26
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Shannan B, Seifert M, Boothman DA, Tilgen W, Reichrath J. Clusterin and DNA repair: a new function in cancer for a key player in apoptosis and cell cycle control. J Mol Histol 2006; 37:183-8. [PMID: 17048076 DOI: 10.1007/s10735-006-9052-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Accepted: 08/09/2006] [Indexed: 12/26/2022]
Abstract
The glycoprotein clusterin (CLU), has two known isoforms generated in human cells. A nuclear form of CLU protein (nCLU) is pro-apoptotic, while a secretory form (sCLU) is pro-survival. Both forms are implicated in various cell functions, including DNA repair, cell cycle regulation, and apoptotic cell death. CLU expression has been associated with tumorigenesis and the progression of various malignancies. In response to DNA damage, cell survival can be enhanced by activation of DNA repair mechanisms, while simultaneously stimulating energy-expensive cell cycle checkpoints that delay the cell cycle progression to allow more time for DNA repair. This review summarizes our current understanding of the role of clusterin in DNA repair, apoptosis, and cell cycle control and the relevance.
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Affiliation(s)
- B Shannan
- Department of Dermatology, The Saarland University Hospital, Building 18, Homburg/Saar 66421, Germany
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Shannan B, Seifert M, Leskov K, Willis J, Boothman D, Tilgen W, Reichrath J. Challenge and promise: roles for clusterin in pathogenesis, progression and therapy of cancer. Cell Death Differ 2006; 13:12-9. [PMID: 16179938 DOI: 10.1038/sj.cdd.4401779] [Citation(s) in RCA: 248] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Clusterin (CLU) has been implicated in various cell functions involved in carcinogenesis and tumour progression. There are two known CLU protein isoforms generated in human cells. A nuclear form of CLU protein (nCLU) is proapoptotic, and a secretory form (sCLU) is prosurvival. CLU expression has been associated with tumorigenesis of various malignancies, including tumours of prostate, colon, and breast. Furthermore, CLU expression is modulated by many factors that are believed to regulate tumour growth and/or apoptosis, including 1,25-dihydroxyvitamin D3, transforming growth factor beta-1, ultraviolet radiation, and IR. sCLU upregulation appears to be a general molecular stress response. Presently, preliminary results indicate that therapeutic modalities targeting CLU may be effective in cancer treatment. However, such strategies should make sure that nCLU is not eliminated or reduced. This review summarizes our present understanding of the importance of CLU in various physiological functions including tumour growth, and discusses its relevance to future cancer therapy.
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Affiliation(s)
- B Shannan
- Department of Dermatology, The Saarland University Hospital, Homburg 66421, Germany
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Bulman RA, Dragani TA, Bouffler SD, Cox R. Locations of mouse DNA damage response and repair loci, and cancer risk modifiers. DNA Repair (Amst) 2006; 5:274-7. [PMID: 16290248 DOI: 10.1016/j.dnarep.2005.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2005] [Revised: 10/04/2005] [Accepted: 10/05/2005] [Indexed: 11/20/2022]
Abstract
An outline is presented of an electronically accessible database that compares the locations of mouse genes involved in DNA repair, apoptosis, cell cycle and signal transduction with those of known cancer risk modifier genes. The database has a primary but not exclusive focus on modifiers of ionizing radiation (IR) cancer risk and genes involved in IR-induced DNA damage responses. The database () provides a useful tool for assessing the role of DNA damage response genes in cancer predisposition.
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Affiliation(s)
- Robert A Bulman
- Radiation Effects Department, Health Protection Agency-Radiation Protection Division, Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot OX11 0RQ, UK.
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Bey EA, Wuerzberger-Davis SM, Pink JJ, Yang CR, Araki S, Reinicke KE, Bentle MS, Dong Y, Cataldo E, Criswell TL, Wagner MW, Li L, Gao J, Boothman DA. Mornings with art, lessons learned: Feedback regulation, restriction threshold biology, and redundancy govern molecular stress responses. J Cell Physiol 2006; 209:604-10. [PMID: 17001694 DOI: 10.1002/jcp.20783] [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: 11/11/2022]
Abstract
Work from the laboratory of Dr. Arthur B. Pardee has highlighted basic principles that govern cellular and molecular biological processes in living cells. Among the most important governing principles in cellular and molecular responses are: (i) threshold "restriction" responses, wherein a level of response is reached and a "point of no return" is achieved; (ii) feedback regulation; and (iii) redundancy. Lessons learned from the molecular biology of cellular stress responses in mammalian cancer versus normal cells after ionizing radiation (IR) or chemotherapeutic agent exposures reveal similar instances of these guiding principles in mammalian cells. Among these are the: (i) induction of cell death responses by beta-lapachone (beta-lap), a naphthoquinone anti-tumor agent that kills cancer cells via an NQO1 (i.e., X-ray-inducible protein-3, xip3)-dependent mechanism; (ii) induction of secretory clusterin (sCLU) in response to TGF-beta1 exposure, and the ability of induced sCLU protein to down-regulate TGF-beta1 signaling; and (iii) induction of DNA mismatch repair-dependent G(2) cell cycle checkpoint responses after exposure to alkylating agents. We have learned these lessons and now adopted strategies to exploit them for improved therapy. These examples will be discussed and compared to the pioneering findings of researchers in the Pardee laboratory over the years.
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Affiliation(s)
- Erik A Bey
- Laboratory of Molecular Stress Responses, Department of Pharmacology and Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
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Abstract
The opportunity to write a historical review of the field of radiation biology allows for the viewing of the development and maturity of a field of study, thereby being able to provide the appropriate context for the earlier years of research and its findings. The pioneering work of Muller, Sax, and McClintock, and many others, has stood the test of time. The idea that x-rays could damage the genetic material and result in interactions that could lead to gene mutations and a range of chromosomal alterations is now interpretable in terms of induced DNA damage and errors of DNA repair. The expanded idea that such genetic alterations can be induced by DNA damage that is produced by one or two tracks of ionizing radiation remains the mainstay of radiation biology. The impact of the more recent molecular approaches to unraveling the mechanism behind this simple concept has confirmed this fundamental observation. The remarkable advances have allowed for a fairly complete understanding of the specific types of DNA damage induced by ionizing radiations and the pivotal role played by the errors of repair of double-strand breaks. Given our considerably enhanced knowledge of the details of the DNA repair processes involved, misrepair is a very unlikely event. The role of potential confounders of the concept of dose-response (e.g., bystander effects, genomic instability, and adaptive responses) is taking on a growing importance to the field. The evolving need is to begin to consider mechanistically-based dose-response models for cancer risk such that any potential impact of confounders on the response at low, environmental doses can be assessed. Thus, radiation biology research has always had a focus on how best to protect human health from radiation exposures and will continue to do so.
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Affiliation(s)
- R Julian Preston
- Environmental Carcinogenesis Division, NHEERL, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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Akerman GS, Rosenzweig BA, Domon OE, Tsai CA, Bishop ME, McGarrity LJ, Macgregor JT, Sistare FD, Chen JJ, Morris SM. Alterations in gene expression profiles and the DNA-damage response in ionizing radiation-exposed TK6 cells. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2005; 45:188-205. [PMID: 15657912 DOI: 10.1002/em.20091] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Identifying genes that are differentially expressed in response to DNA damage may help elucidate markers for genetic damage and provide insight into the cellular responses to specific genotoxic agents. We utilized cDNA microarrays to develop gene expression profiles for ionizing radiation-exposed human lymphoblastoid TK6 cells. In order to relate changes in the expression profiles to biological responses, the effects of ionizing radiation on cell viability, cloning efficiency, and micronucleus formation were measured. TK6 cells were exposed to 0.5, 1, 5, 10, and 20 Gy ionizing radiation and cultured for 4 or 24 hr. A significant (P < 0.0001) decrease in cloning efficiency was observed at all doses at 4 and 24 hr after exposure. Flow cytometry revealed significant decreases in cell viability at 24 hr in cells exposed to 5 (P < 0.001), 10 (P < 0.0001), and 20 Gy (P < 0.0001). An increase in micronucleus frequency occurred at both 4 and 24 hr at 0.5 and 1 Gy; however, insufficient binucleated cells were present for analysis at the higher doses. Gene expression profiles were developed from mRNA isolated from cells exposed to 5, 10, and 20 Gy using a 350 gene human cDNA array platform. Overall, more genes were differentially expressed at 24-hr than at the 4-hr time point. The genes upregulated (> 1.5-fold) or downregulated (< 0.67-fold) at 4 hr were those primarily involved in the cessation of the cell cycle, cellular detoxification pathways, DNA repair, and apoptosis. At 24 hr, glutathione-associated genes were induced in addition to genes involved in apoptosis. Genes involved in cell cycle progression and mitosis were downregulated at 24 hr. Real-time quantitative PCR was used to confirm the microarray results and to evaluate expression levels of selected genes at the low doses (0.5 and 1.0 Gy). The expression profiles reflect the cellular and molecular responses to ionizing radiation related to the recognition of DNA damage, a halt in progression through the cell cycle, activation of DNA-repair pathways, and the promotion of apoptosis.
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Affiliation(s)
- Gregory S Akerman
- Division of Genetic and Reproductive Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas 72079, USA
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Boothman DA, Reichrath J. New basic science initiatives for improved understanding of radiation-induced multi-organ dysfunction syndrome (MODS). Br J Radiol 2005. [DOI: 10.1259/bjr/19036098] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Caccamo A, Scaltriti M, Caporali A, D'Arca D, Scorcioni F, Astancolle S, Mangiola M, Bettuzzi S. Cell detachment and apoptosis induction of immortalized human prostate epithelial cells are associated with early accumulation of a 45 kDa nuclear isoform of clusterin. Biochem J 2004; 382:157-68. [PMID: 15139853 PMCID: PMC1133926 DOI: 10.1042/bj20040158] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2004] [Revised: 04/15/2004] [Accepted: 05/12/2004] [Indexed: 12/21/2022]
Abstract
Clusterin, ubiquitously distributed in mammalians, was cloned and identified as the most potently induced gene during rat prostate involution following androgen deprivation. Also found to be involved in many other patho-physiological processes, its biological significance is still controversial, particularly with regard to apoptosis. We previously showed that transient over-expression of clusterin blocked cell cycle progression of simian-virus-40-immortalized human prostate epithelial cell lines PNT1A and PNT2. We show in the present study that the accumulation of an intracellular 45 kDa clusterin isoform was an early event closely associated with death of PNT1A cells caused by cell detachment followed by apoptosis induction (anoikis). Cell morphological changes, decreased proliferation rate and cell cycle arrest at G0/G1-S-phase checkpoint were all strictly associated with the production and early translocation to the nucleus of a 45 kDa clusterin isoform. Later, nuclear clusterin was found accumulated in detached cells and apoptotic bodies. These results suggest that a 45 kDa isoform of clusterin, when targeted to the nucleus, can decrease cell proliferation and promotes cell-detachment-induced apoptosis, suggesting a possible major role for clusterin as an anti-proliferative gene in human prostate epithelial cells.
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Key Words
- anoikis
- apoptosis
- caspase
- clusterin
- pnt1a cell
- prostate cancer
- dapi, 4,6-diamidino-2-phenylindole
- devd-pna, asp-glu-val-asp-p-nitroanilide
- fak, focal adhesion kinase
- fbs, foetal bovine serum
- gapdh, glyceraldehyde-3-phosphate dehydrogenase
- ksfm, keratinocyte serum-free complete medium
- p-fak-tyr397, phosphorylated fak
- par, poly(adp-ribose)
- parp, par polymerase
- pna, p-nitroanilide
- sv40, simian virus 40
- ttbs, tris-buffered saline/tween
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Affiliation(s)
- Alessandro E. Caccamo
- *Dipartimento di Medicina Sperimentale, University of Parma, Via Volturno 39, 43100 Parma, Italy
| | - Maurizio Scaltriti
- *Dipartimento di Medicina Sperimentale, University of Parma, Via Volturno 39, 43100 Parma, Italy
| | - Andrea Caporali
- *Dipartimento di Medicina Sperimentale, University of Parma, Via Volturno 39, 43100 Parma, Italy
| | - Domenico D'Arca
- †Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, Modena, Italy
| | - Francesca Scorcioni
- †Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, Modena, Italy
| | - Serenella Astancolle
- †Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, Modena, Italy
| | - Massimo Mangiola
- ‡Dipartimento di Oncologia, Biologia e Genetica, Università di Genova, Genova, Italy
| | - Saverio Bettuzzi
- *Dipartimento di Medicina Sperimentale, University of Parma, Via Volturno 39, 43100 Parma, Italy
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Akerman GS, Rosenzweig BA, Domon OE, McGarrity LJ, Blankenship LR, Tsai CA, Culp SJ, MacGregor JT, Sistare FD, Chen JJ, Morris SM. Gene expression profiles and genetic damage in benzo(a)pyrene diol epoxide-exposed TK6 cells. Mutat Res 2004; 549:43-64. [PMID: 15120962 DOI: 10.1016/j.mrfmmm.2003.11.013] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2003] [Revised: 11/21/2003] [Accepted: 11/25/2003] [Indexed: 12/23/2022]
Abstract
Microarray analysis is a powerful tool to identify the biological effects of drugs or chemicals on cellular gene expression. In this study, we compare the relationships between traditional measures of genetic toxicology and mutagen-induced alterations in gene expression profiles. TK6 cells were incubated with 0.01, 0.1, or 1.0 microM +/-anti-benzo(a)pyrene-trans-7,8-dihydrodiol-9,10-epoxide (BPDE) for 4 h and then cultured for an additional 20 h. Aliquots of the exposed cells were removed at 4 and 24 h in order to quantify DNA adduct levels by 32P post-labeling and measure cell viability by cloning efficiency and flow cytometry. Gene expression profiles were developed by extracting total RNA from the control and exposed cells at 4 and 24 h, labeling with Cy3 or Cy5 and hybridizing to a human 350 gene array. Mutant frequencies in the Thymidine Kinase and Hypoxanthine Phosphoribosyl Transferase genes were also determined. The 10alpha-(deoxyguanosin-N(2)-yl)-7alpha,8beta,9beta-trihydroxy-7,8,9,10-tetrahydrobenzo(a)pyrene (dG-N(2)-BPDE) adduct increased as a function of dose and was the only adduct identified. A dose-related decrease in cell viability was evident at 24 h, but not at 4 h. Cell death occurred by apoptosis. At 4 h, analysis of the gene expression profiles revealed that Glutathione Peroxidase and Gadd45 were consistently upregulated (greater than 1.5-fold and significantly (P < 0.001) greater than the control in two experiments) in response to 1.0 microM BPDE exposure. Fifteen genes were consistently down-regulated (less than 0.67-fold and significantly (P < 0.001) lower than the control in two experiments) at 4 h in cultures exposed to 1.0 microM BPDE. Genes with altered expression at 4 h included genes important in the progression of the cell-cycle and those that inhibit apoptosis. At 24 h post-exposure, 16 genes, involved in cell-cycle control, detoxification, and apoptosis were consistently upregulated; 10 genes were repressed in cultures exposed to the high dose of BPDE. Real-time quantitative PCR confirmed the differential expression of selected genes. These data suggest that changes in gene expression will help to identify effects of drugs and chemicals on molecular pathways in cells, and will provide useful information about the molecular responses associated with DNA damage. Of the endpoints evaluated, DNA adduct formation was the most sensitive indicator of DNA damage. DNA adduct formation was clearly evident at low doses, but the number of genes with significantly altered expression (P < 0.001) was minimal. Alterations in gene expression were more robust at doses associated with cellular toxicity and induction of mutations.
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Affiliation(s)
- G S Akerman
- Division of Genetic and Reproductive Toxicology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079, USA
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35
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Scott BR, Walker DM, Walker VE. Low-dose radiation and genotoxic chemicals can protect against stochastic biological effects. NONLINEARITY IN BIOLOGY, TOXICOLOGY, MEDICINE 2004; 2:185-211. [PMID: 19330143 PMCID: PMC2657487 DOI: 10.1080/15401420490507602] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A protective apoptosis-mediated (PAM) process that is turned on in mammalian cells by low-dose photon (X and gamma) radiation and appears to also be turned on by the genotoxic chemical ethylene oxide is discussed. Because of the PAM process, exposure to low-dose photon radiation (and possibly also some genotoxic chemicals) can lead to a reduction in the risk of stochastic effects such as problematic mutations, neoplastic transformation (an early step in cancer occurrence), and cancer. These findings indicate a need to revise the current low-dose risk assessment paradigm for which risk of cancer is presumed to increase linearly with dose (without a threshold) after exposure to any amount of a genotoxic agent such as ionizing radiation. These findings support a view seldom mentioned in the past, that cancer risk can actually decrease, rather than increase, after exposure to low doses of photon radiation and possibly some other genotoxic agents. The PAM process (a form of natural protection) may contribute substantially to cancer prevention in humans and other mammals. However, new research is needed to improve our understanding of the process. The new research could unlock novel strategies for optimizing cancer prevention and novel protocols for low-dose therapy for cancer. With low-dose cancer therapy, normal tissue could be spared from severe damage while possibly eliminating the cancer.
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Affiliation(s)
- Bobby R Scott
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
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Abstract
The opportunity to write a historical review of the field of radiation biology allows for the viewing of the development and maturity of a field of study, thereby being able to provide the appropriate context for the earlier years of research and its findings. The pioneering work of Muller, Sax, and McClintock, and many others, has stood the test of time. The idea that x-rays could damage the genetic material and result in interactions that could lead to gene mutations and a range of chromosomal alterations is now interpretable in terms of induced DNA damage and errors of DNA repair. The expanded idea that such genetic alterations can be induced by DNA damage that is produced by one or two tracks of ionizing radiation remains the mainstay of radiation biology. The impact of the more recent molecular approaches to unraveling the mechanism behind this simple concept has confirmed this fundamental observation. The remarkable advances have allowed for a fairly complete understanding of the specific types of DNA damage induced by ionizing radiations and the pivotal role played by the errors of repair of double-strand breaks. Given our considerably enhanced knowledge of the details of the DNA repair processes involved, misrepair is a very unlikely event. The role of potential confounders of the concept of dose-response (e.g., bystander effects, genomic instability, and adaptive responses) is taking on a growing importance to the field. The evolving need is to begin to consider mechanistically-based dose-response models for cancer risk such that any potential impact of confounders on the response at low, environmental doses can be assessed. Thus, radiation biology research has always had a focus on how best to protect human health from radiation exposures and will continue to do so.
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Affiliation(s)
- R Julian Preston
- Environmental Carcinogenesis Division, NHEERL, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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37
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Nestler U, Wakimoto H, Siller-Lopez F, Aguilar LK, Chakravarti A, Muzikansky A, Stemmer-Rachamimov A, Chiocca EA, Aguilar-Cordova E, Hochberg FH. The combination of adenoviral HSV TK gene therapy and radiation is effective in athymic mouse glioblastoma xenografts without increasing toxic side effects. J Neurooncol 2004; 67:177-88. [PMID: 15072465 DOI: 10.1023/b:neon.0000021897.53969.ca] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECT In mouse models of prostate and breast cancer therapeutic effects are enhanced when adenoviral HSV TK gene therapy is combined with ionizing radiation. In the present study, we adopted this approach for the treatment of human glioblastoma xenografts in an athymic mouse model and assessed treatment results as well as toxic side effects. METHODS About 72 nude mice received intracerebral inoculations of 2 x 10(5) U87deltaEGFR cells. On day 7 after tumor implantation the study population was randomized into six treatment arms: (1) intratumoral buffer inoculation on day 7, (2) intratumoral adenoviral vector injection (2 x 10(9) vp) on day 7, (3) single dose radiation (2.1 Gy) on day 9, (4) adenoviral injection + radiation, (5) adenoviral injection + ganciclovir (GCV) (20 microg/g twice daily from day 8 to 17), (6) adenoviral injection + GCV + radiation. On day 21 half of the animals were sacrificed for histological evaluation of the brain tumors, the other half was assessed for survival. RESULTS This study showed significantly prolonged median survival time of 5 days for the GCV treated groups. The addition of radiation decreased the frequency of neurological symptoms and delayed the onset of deficits without altering the expression of thymidine kinase in the tumor cells. CONCLUSIONS We conclude that adenoviral HSV TK gene therapy in combination with adjuvant radiotherapy does not generate increased toxic side effects in glioblastoma treatment. The prolonged survival time of animals receiving gene therapy and the reduced occurrence of neurological symptoms in irradiated mice constitute promising features of the combined treatment.
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Affiliation(s)
- Ulf Nestler
- Molecular Neuro-Oncology Laboratory, Department of Radiation Oncology, Massachusetts General Hospital East, Charlestown, MA, USA.
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38
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Marples B, Wouters BG, Collis SJ, Chalmers AJ, Joiner MC. Low-Dose Hyper-radiosensitivity: A Consequence of Ineffective Cell Cycle Arrest of Radiation-Damaged G2-Phase Cells. Radiat Res 2004; 161:247-55. [PMID: 14982490 DOI: 10.1667/rr3130] [Citation(s) in RCA: 182] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
This review highlights the phenomenon of low-dose hyper- radiosensitivity (HRS), an effect in which cells die from excessive sensitivity to small single doses of ionizing radiation but become more resistant (per unit dose) to larger single doses. Established and new data pertaining to HRS are discussed with respect to its possible underlying molecular mechanisms. To explain HRS, a three-component model is proposed that consists of damage recognition, signal transduction and damage repair. The foundation of the model is a rapidly occurring dose-dependent pre-mitotic cell cycle checkpoint that is specific to cells irradiated in the G2phase. This checkpoint exhibits a dose expression profile that is identical to the cell survival pattern that characterizes HRS and is probably the key control element of low-dose radiosensitivity. This premise is strengthened by the recent observation coupling low- dose radiosensitivity of G2-phase cells directly to HRS. The putative role of known damage response factors such as ATM, PARP, H2AX, 53BP1 and HDAC4 is also included within the framework of the HRS model.
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Affiliation(s)
- B Marples
- Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201-2013, USA.
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39
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Ma JL, Kim EM, Haber JE, Lee SE. Yeast Mre11 and Rad1 proteins define a Ku-independent mechanism to repair double-strand breaks lacking overlapping end sequences. Mol Cell Biol 2003; 23:8820-8. [PMID: 14612421 PMCID: PMC262689 DOI: 10.1128/mcb.23.23.8820-8828.2003] [Citation(s) in RCA: 278] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2003] [Revised: 08/19/2003] [Accepted: 08/27/2003] [Indexed: 12/22/2022] Open
Abstract
End joining of double-strand breaks (DSBs) requires Ku proteins and frequently involves base pairing between complementary terminal sequences. To define the role of terminal base pairing in end joining, two oppositely oriented HO endonuclease cleavage sites separated by 2.0 kb were integrated into yeast chromosome III, where constitutive expression of HO endonuclease creates two simultaneous DSBs with no complementary end sequence. Lack of complementary sequence in their 3' single-strand overhangs facilitates efficient repair events distinctly different from when the 3' ends have a 4-bp sequence base paired in various ways to create 2- to 3-bp insertions. Repair of noncomplementary ends results in a set of nonrandom deletions of up to 302 bp, annealed by imperfect microhomology of about 8 to 10 bp at the junctions. This microhomology-mediated end joining (MMEJ) is Ku independent, but strongly dependent on Mre11, Rad50, and Rad1 proteins and partially dependent on Dnl4 protein. The MMEJ also occurs when Rad52 is absent, but the extent of deletions becomes more limited. The increased gamma ray sensitivity of rad1Delta rad52Delta yku70Delta strains compared to rad52Delta yku70Delta strains suggests that MMEJ also contributes to the repair of DSBs induced by ionizing radiation.
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Affiliation(s)
- Jia-Lin Ma
- Department of Molecular Medicine, Institute of Biotechnology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas 78245, USA
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40
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Tzfira T, Frankman LR, Vaidya M, Citovsky V. Site-specific integration of Agrobacterium tumefaciens T-DNA via double-stranded intermediates. PLANT PHYSIOLOGY 2003; 133:1011-23. [PMID: 14551323 PMCID: PMC281598 DOI: 10.1104/pp.103.032128] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2003] [Revised: 08/28/2003] [Accepted: 08/28/2003] [Indexed: 05/18/2023]
Abstract
Agrobacterium tumefaciens-mediated genetic transformation involves transfer of a single-stranded T-DNA molecule (T strand) into the host cell, followed by its integration into the plant genome. The molecular mechanism of T-DNA integration, the culmination point of the entire transformation process, remains largely obscure. Here, we studied the roles of double-stranded breaks (DSBs) and double-stranded T-DNA intermediates in the integration process. We produced transgenic tobacco (Nicotiana tabacum) plants carrying an I-SceI endonuclease recognition site that, upon cleavage with I-SceI, generates DSB. Then, we retransformed these plants with two A. tumefaciens strains: one that allows transient expression of I-SceI to induce DSB and the other that carries a T-DNA with the I-SceI site and an integration selection marker. Integration of this latter T-DNA as full-length and I-SceI-digested molecules into the DSB site was analyzed in the resulting plants. Of 620 transgenic plants, 16 plants integrated T-DNA into DSB at their I-SceI sites; because DSB induces DNA repair, these results suggest that the invading T-DNA molecules target to the DNA repair sites for integration. Furthermore, of these 16 plants, seven plants incorporated T-DNA digested with I-SceI, which cleaves only double-stranded DNA. Thus, T-strand molecules can be converted into double-stranded intermediates before their integration into the DSB sites within the host cell genome.
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Affiliation(s)
- Tzvi Tzfira
- Department of Biochemistry and Cell Biology, State University of New York, Stony Brook, New York 11794, USA.
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41
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Marples B, Wouters BG, Joiner MC. An association between the radiation-induced arrest of G2-phase cells and low-dose hyper-radiosensitivity: a plausible underlying mechanism? Radiat Res 2003; 160:38-45. [PMID: 12816521 DOI: 10.1667/rr3013] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The survival of asynchronous and highly enriched G1-, S- and G2-phase populations of Chinese hamster V79 cells was measured after irradiation with 60Co gamma rays (0.1-10 Gy) using a precise flow cytometry-based clonogenic survival assay. The high-dose survival responses demonstrated a conventional relationship, with G2-phase cells being the most radiosensitive and S-phase cells the most radioresistant. Below 1 Gy, distinct low-dose hyper-radiosensitivity (HRS) responses were observed for the asynchronous and G2-phase enriched cell populations, with no evidence of HRS in the G1- and S-phase populations. Modeling supports the conclusion that HRS in asynchronous V79 populations is explained entirely by the HRS response of G2-phase cells. An association was discovered between the occurrence of HRS and the induction of a novel G2-phase arrest checkpoint that is specific for cells that are in the G2 phase of the cell cycle at the time of irradiation. Human T98G cells and hamster V79 cells, which both exhibit HRS in asynchronous cultures, failed to arrest the entry into mitosis of damaged G2-phase cells at doses less than 30 cGy, as determined by the flow cytometric assessment of the phosphorylation of histone H3, an established indicator of mitosis. In contrast, human U373 cells that do not show HRS induced this G2-phase checkpoint in a dose-independent manner. These data suggest that HRS may be a consequence of radiation-damaged G2-phase cells prematurely entering mitosis.
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Affiliation(s)
- B Marples
- Radiation Biology Group, Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201-2013, USA.
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42
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Coleman CN. Linking radiation oncology and imaging through molecular biology (or now that therapy and diagnosis have separated, it's time to get together again!). Radiology 2003; 228:29-35. [PMID: 12832573 DOI: 10.1148/radiol.2281021567] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Among the areas defined by the National Cancer Institute as "Extraordinary Opportunities for Research Investment" that are highly relevant to the technology-oriented disciplines within the broad field of radiology are cancer imaging, defining the signatures (ie, underlying molecular features) of cancer cells, and molecular targets of prevention and treatment. In molecular target credentialing, a specific molecular target is imaged, the molecular signature is defined, a treatment is given, and the effect of the intervention on the image findings and the signature is then evaluated. Such an approach is used to validate the proposed target as a legitimate one for cancer therapy or prevention and to provide the opportunity to ultimately individualize therapy on the basis of both the initial characteristics of the tumor and the tumor's response to an intervention. Therapeutic radiation is focused biology (ie, radiation produces molecular events in the irradiated tissue). Radiation can (a) kill cancer cells by itself, (b) be combined with cytotoxic or cytostatic drugs, and (c) serve to initiate radiation-inducible molecular targets that are amenable to treatment with drugs and/or biologic therapies. Focused biology can be anatomically confined with various types of external beams and with brachytherapy, and it can be used systemically with targeted radioisotopes. These new paradigms link diagnostic imaging, radiation therapy, and nuclear medicine in unique ways by way of basic biology. It is timely to develop new collaborative research, training, and education agendas by building on one another's expertise and adopting new fields of microtechnology, nanotechnology, and mathematical analysis and optimization.
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Affiliation(s)
- C Norman Coleman
- National Cancer Institute, Radiation Oncology Branch, Bldg 10, B3-B69, National Institutes of Health, Bethesda, MD 20892-1002, USA.
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Leskov KS, Klokov DY, Li J, Kinsella TJ, Boothman DA. Synthesis and functional analyses of nuclear clusterin, a cell death protein. J Biol Chem 2003; 278:11590-600. [PMID: 12551933 DOI: 10.1074/jbc.m209233200] [Citation(s) in RCA: 304] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Nuclear clusterin (nCLU) is an ionizing radiation (IR)-inducible protein that binds Ku70, and triggers apoptosis when overexpressed in MCF-7 cells. We demonstrate that endogenous nCLU synthesis is a product of alternative splicing. Reverse transcriptase-PCR analyses revealed that exon II, containing the first AUG and encoding the endoplasmic reticulum-targeting peptide, was omitted. Exons I and III are spliced together placing a downstream AUG in exon III as the first available translation start site. This shorter mRNA produces the 49-kDa precursor nCLU protein. Ku70 binding activity was localized to the C-terminal coiled-coil domain of nCLU. Leucine residues 357, 358, and 361 of nCLU were necessary for Ku70-nCLU interaction. The N- and C-terminal coiled-coil domains of nCLU interacted with each other, suggesting that the protein could dimerize or fold. Mutation analyses indicate that the C-terminal NLS was functional in nCLU with the same contribution from N-terminal NLS. The C-terminal coiled-coil domain of nCLU was the minimal region required for Ku binding and apoptosis. MCF-7 cells show nuclear as well as cytoplasmic expression of GFP-nCLU in apoptotic cells. Cytosolic aggregation of GFP-nCLU was found in viable cells. These results indicate that an inactive precursor of nCLU exists in the cytoplasm of non-irradiated MCF-7 cells, translocates into the nucleus following IR, and induces apoptosis.
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Affiliation(s)
- Konstantin S Leskov
- Department of Radiation Oncology, Laboratory of Molecular Stress Responses, Ireland Comprehensive Cancer Center and Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4942, USA
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44
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Abstract
Human immortalized keratinocytes were exposed to a range of single or fractionated doses of gamma rays from (60)Co, to medium harvested from donor cells exposed to these protocols, or to a combination of radiation and irradiated cell conditioned medium (ICCM). The surviving fractions after direct irradiation or exposure to ICCM were determined using a clonogenic assay. The results show that medium harvested from cultures receiving fractionated irradiation gave lower "recovery factors" than direct fractionated irradiation, where normal split-dose recovery occurred. The recovery factor is defined here as the surviving fraction of the cells receiving two doses (direct or ICCM) separated by an interval of 2 h divided by the surviving fraction of cells receiving the same dose in one exposure. After treatment with ICCM, the recovery factors were less than 1 over a range of total doses from 5 mGy-5 Gy. Varying the time between doses from 10 min to 180 min did not alter the effect of ICCM, suggesting that two exposures to ICCM are more toxic than one irrespective of the dose used to generate the response. In certain protocols using mixtures of direct irradiation and ICCM, it was possible to eliminate the bystander effect. If bystander factors are produced in vivo, then they may reduce the sparing effect of the dose fractionation.
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Affiliation(s)
- Carmel Mothersill
- Radiation and Environmental Science Centre, Dublin Institute of Technology, Fitzwilliam House, 30 Upper Pembroke Street, Dublin 2, Ireland.
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