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Huang S, Wang LL, Xue NN, Li C, Guo HH, Ren TK, Zhan Y, Li WB, Zhang J, Chen XG, Han YX, Zhang JL, Jiang JD. Chlorogenic acid effectively treats cancers through induction of cancer cell differentiation. Theranostics 2019; 9:6745-6763. [PMID: 31660066 PMCID: PMC6815948 DOI: 10.7150/thno.34674] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 07/31/2019] [Indexed: 02/06/2023] Open
Abstract
Rationale: Inducing cancer differentiation is a promising approach to treat cancer. Here, we identified chlorogenic acid (CA), a potential differentiation inducer, for cancer therapy, and elucidated the molecular mechanisms underlying its differentiation-inducing effects on cancer cells. Methods: Cancer cell differentiation was investigated by measuring malignant behavior, including growth rate, invasion/migration, morphological change, maturation, and ATP production. Gene expression was analyzed by microarray analysis, qRT-PCR, and protein measurement, and molecular biology techniques were employed for mechanistic studies. LC/MS analysis was the method of choice for chemical detection. Finally, the anticancer effect of CA was evaluated both in vitro and in vivo. Results: Cancer cells treated with CA showed reduced proliferation rate, migration/invasion ability, and mitochondrial ATP production. Treating cancer cells with CA resulted in elevated SUMO1 expression through acting on its 3'UTR and stabilizing the mRNA. The increased SUMO1 caused c-Myc sumoylation, miR-17 family downregulation, and p21 upregulation leading to G0/G1 arrest and maturation phenotype. CA altered the expression of differentiation-related genes in cancer cells but not in normal cells. It inhibited hepatoma and lung cancer growth in tumor-bearing mice and prevented new tumor development in naïve mice. In glioma cells, CA increased expression of specific differentiation biomarkers Tuj1 and GFAP inducing differentiation and reducing sphere formation. The therapeutic efficacy of CA in glioma cells was comparable to that of temozolomide. CA was detectable both in the blood and brain when administered intraperitoneally in animals. Most importantly, CA was safe even at very high doses. Conclusion: CA might be a safe and effective differentiation-inducer for cancer therapy. “Educating” cancer cells to differentiate, rather than killing them, could be a novel therapeutic strategy for cancer.
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Co-Inhibition of the DNA Damage Response and CHK1 Enhances Apoptosis of Neuroblastoma Cells. Int J Mol Sci 2019; 20:ijms20153700. [PMID: 31362335 PMCID: PMC6696225 DOI: 10.3390/ijms20153700] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 07/22/2019] [Accepted: 07/23/2019] [Indexed: 01/25/2023] Open
Abstract
Checkpoint kinase 1 (CHK1) is a central mediator of the DNA damage response (DDR) at the S and G2/M cell cycle checkpoints, and plays a crucial role in preserving genomic integrity. CHK1 overexpression is thought to contribute to cancer aggressiveness, and several selective inhibitors of this kinase are in clinical development for various cancers, including neuroblastoma (NB). Here, we examined the sensitivity of MYCN-amplified NB cell lines to the CHK1 inhibitor PF-477736 and explored mechanisms to increase its efficacy. PF-477736 treatment of two sensitive NB cell lines, SMS-SAN and CHP134, increased the expression of two pro-apoptotic proteins, BAX and PUMA, providing a mechanism for the effect of the CHK1 inhibitor. In contrast, in NB-39-nu and SK-N-BE cell lines, PF-477736 induced DNA double-strand breaks and activated the ataxia telangiectasia mutated serine/threonine kinase (ATM)-p53-p21 axis of the DDR pathway, which rendered the cells relatively insensitive to the antiproliferative effects of the CHK1 inhibitor. Interestingly, combined treatment with PF-477736 and the ATM inhibitor Ku55933 overcame the insensitivity of NB-39-nu and SK-N-BE cells to CHK1 inhibition and induced mitotic cell death. Similarly, co-treatment with PF-477736 and NU7441, a pharmacological inhibitor of DNA-PK, which is also essential for the DDR pathway, rendered the cells sensitive to CHK1 inhibition. Taken together, our results suggest that synthetic lethality between inhibitors of CHK1 and the DDR drives G2/M checkpoint abrogation and could be a novel potential therapeutic strategy for NB.
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Halldorsson BV, Palsson G, Stefansson OA, Jonsson H, Hardarson MT, Eggertsson HP, Gunnarsson B, Oddsson A, Halldorsson GH, Zink F, Gudjonsson SA, Frigge ML, Thorleifsson G, Sigurdsson A, Stacey SN, Sulem P, Masson G, Helgason A, Gudbjartsson DF, Thorsteinsdottir U, Stefansson K. Characterizing mutagenic effects of recombination through a sequence-level genetic map. Science 2019; 363:363/6425/eaau1043. [DOI: 10.1126/science.aau1043] [Citation(s) in RCA: 156] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 05/16/2018] [Accepted: 12/07/2018] [Indexed: 12/14/2022]
Abstract
Genetic diversity arises from recombination and de novo mutation (DNM). Using a combination of microarray genotype and whole-genome sequence data on parent-child pairs, we identified 4,531,535 crossover recombinations and 200,435 DNMs. The resulting genetic map has a resolution of 682 base pairs. Crossovers exhibit a mutagenic effect, with overrepresentation of DNMs within 1 kilobase of crossovers in males and females. In females, a higher mutation rate is observed up to 40 kilobases from crossovers, particularly for complex crossovers, which increase with maternal age. We identified 35 loci associated with the recombination rate or the location of crossovers, demonstrating extensive genetic control of meiotic recombination, and our results highlight genes linked to the formation of the synaptonemal complex as determinants of crossovers.
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Vrijens K, Winckelmans E, Tsamou M, Baeyens W, De Boever P, Jennen D, de Kok TM, Den Hond E, Lefebvre W, Plusquin M, Reynders H, Schoeters G, Van Larebeke N, Vanpoucke C, Kleinjans J, Nawrot TS. Sex-Specific Associations between Particulate Matter Exposure and Gene Expression in Independent Discovery and Validation Cohorts of Middle-Aged Men and Women. ENVIRONMENTAL HEALTH PERSPECTIVES 2017; 125:660-669. [PMID: 27740511 PMCID: PMC5381989 DOI: 10.1289/ehp370] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 08/12/2016] [Accepted: 08/22/2016] [Indexed: 05/05/2023]
Abstract
BACKGROUND Particulate matter (PM) exposure leads to premature death, mainly due to respiratory and cardiovascular diseases. OBJECTIVES Identification of transcriptomic biomarkers of air pollution exposure and effect in a healthy adult population. METHODS Microarray analyses were performed in 98 healthy volunteers (48 men, 50 women). The expression of eight sex-specific candidate biomarker genes (significantly associated with PM10 in the discovery cohort and with a reported link to air pollution-related disease) was measured with qPCR in an independent validation cohort (75 men, 94 women). Pathway analysis was performed using Gene Set Enrichment Analysis. Average daily PM2.5 and PM10 exposures over 2-years were estimated for each participant's residential address using spatiotemporal interpolation in combination with a dispersion model. RESULTS Average long-term PM10 was 25.9 (± 5.4) and 23.7 (± 2.3) μg/m3 in the discovery and validation cohorts, respectively. In discovery analysis, associations between PM10 and the expression of individual genes differed by sex. In the validation cohort, long-term PM10 was associated with the expression of DNAJB5 and EAPP in men and ARHGAP4 (p = 0.053) in women. AKAP6 and LIMK1 were significantly associated with PM10 in women, although associations differed in direction between the discovery and validation cohorts. Expression of the eight candidate genes in the discovery cohort differentiated between validation cohort participants with high versus low PM10 exposure (area under the receiver operating curve = 0.92; 95% CI: 0.85, 1.00; p = 0.0002 in men, 0.86; 95% CI: 0.76, 0.96; p = 0.004 in women). CONCLUSIONS Expression of the sex-specific candidate genes identified in the discovery population predicted PM10 exposure in an independent cohort of adults from the same area. Confirmation in other populations may further support this as a new approach for exposure assessment, and may contribute to the discovery of molecular mechanisms for PM-induced health effects.
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Affiliation(s)
- Karen Vrijens
- Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - Ellen Winckelmans
- Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - Maria Tsamou
- Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - Willy Baeyens
- Department of Analytical and Environmental Chemistry, Free University of Brussels, Brussels, Belgium
| | - Patrick De Boever
- Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
- Environmental Risk and Health Unit, Flemish Institute for Technological Research (VITO), Mol, Belgium
| | - Danyel Jennen
- Department of Toxicogenomics, Maastricht University, Maastricht, Netherlands
| | - Theo M. de Kok
- Department of Toxicogenomics, Maastricht University, Maastricht, Netherlands
| | - Elly Den Hond
- Environmental Risk and Health Unit, Flemish Institute for Technological Research (VITO), Mol, Belgium
- Provincial Institute for Hygiene, Antwerp, Belgium
| | - Wouter Lefebvre
- Environmental Risk and Health Unit, Flemish Institute for Technological Research (VITO), Mol, Belgium
| | - Michelle Plusquin
- Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - Hans Reynders
- Environment, Nature and Energy Department, Flemish Government, Brussels, Belgium
| | - Greet Schoeters
- Environmental Risk and Health Unit, Flemish Institute for Technological Research (VITO), Mol, Belgium
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
- University of Southern Denmark, Institute of Public Health, Department of Environmental Medicine, Odense, Denmark
| | - Nicolas Van Larebeke
- Department of Radiotherapy and Nuclear Medicine, Ghent University, Ghent, Belgium
| | | | - Jos Kleinjans
- Department of Toxicogenomics, Maastricht University, Maastricht, Netherlands
| | - Tim S. Nawrot
- Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
- Department of Public Health and Primary Care, Leuven University, Leuven, Belgium
- Address correspondence to T.S. Nawrot, Centre for Environmental Sciences, Hasselt University, Agoralaan gebouw D, B-3590 Diepenbeek, Belgium. Telephone: 0032/11-26.83.82. E-mail:
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Dynamic changes in protein interaction between AKAP95 and Cx43 during cell cycle progression of A549 cells. Sci Rep 2016; 6:21224. [PMID: 26880274 PMCID: PMC4754773 DOI: 10.1038/srep21224] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 01/20/2016] [Indexed: 01/11/2023] Open
Abstract
Here we show that A-kinase anchoring protein 95 (AKAP95) and connexin 43 (Cx43) dynamically interact during cell cycle progression of lung cancer A549 cells. Interaction between AKAP95 and Cx43 at different cell cycle phases was examined by tandem mass spectrometry(MS/MS), confocal immunofluorescence microscopy, Western blot, and co-immunoprecipitation(Co-IP). Over the course of a complete cell cycle, interaction between AKAP95 and Cx43 occurred in two stages: binding stage from late G1 to metaphase, and separating stage from anaphase to late G1. The binding stage was further subdivided into complex binding to DNA in interphase and complex separating from DNA in metaphase. In late G1, Cx43 translocated to the nucleus via AKAP95; in anaphase, Cx43 separated from AKAP95 and aggregated between two daughter nuclei. In telophase, Cx43 aggregated at the membrane of the cleavage furrow. After mitosis, Cx43 was absent from the furrow membrane and was located in the cytoplasm. Binding between AKAP95 and Cx43 was reduced by N-(2-[P-Bromocinnamylamino]-ethyl)-5-isoquinolinesulfonmide (H89) treatment and enhanced by Forskolin. dynamic interaction between AKAP95 and Cx43 varies with cell cycle progression to regulate multiple biological processes.
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Kong XY, Zhang DC, Zhuang WX, Hua SH, Dai Y, Yuan YY, Feng LL, Huang Q, Teng BG, Yu XY, Liu WZ, Zhang YX. AKAP95 promotes cell cycle progression via interactions with cyclin E and low molecular weight cyclin E. Am J Transl Res 2016; 8:811-826. [PMID: 27158371 PMCID: PMC4846928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 02/12/2016] [Indexed: 06/05/2023]
Abstract
AKAP95 in lung cancer tissues showed higher expression than in paracancerous tissues. AKAP95 can bind with cyclin D and cyclin E during G1/S cell cycle transition, but its molecular mechanisms remain unclear. To identify the mechanism of AKAP95 in cell cycle progression, we performed AKAP95 transfection and silencing in A549 cells, examined AKAP95, cyclin E1 and cyclin E2 expression, and the interactions of AKAP95 with cyclins E1 and E2. Results showed that over-expression of AKAP95 promoted cell growth and AKAP95 bound cyclin E1 and E2, low molecular weight cyclin E1 (LWM-E1) and LWM-E2. Additionally AKAP95 bound cyclin E1 and LMW-E2 in the nucleus during G1/S transition, bound LMW-E1 during G1, S and G2/M, and bound cyclin E2 mainly on the nuclear membrane during interphase. Cyclin E2 and LMW-E2 were also detected. AKAP95 over-expression increased cyclin E1 and LMW-E2 expression but decreased cyclin E2 levels. Unlike cyclin E1 and LMW-E2 that were nuclear located during the G1, S and G1/S phases, cyclin E2 and LMW-E1 were expressed in all cell cycle phases, with cyclin E2 present in the cytoplasm and nuclear membrane, with traces in the nucleus. LMW-E1 was present in both the cytoplasm and nucleus. The 20 kDa form of LMW-E1 showed only cytoplasmic expression, while the 40 kDa form was nuclear expressed. The expression of AKAP95, cyclin E1, LMW-E1 and -E2, might be regulated by cAMP. We conclude that AKAP95 might promote cell cycle progression by interacting with cyclin E1 and LMW-E2. LMW-E2, but not cyclin E2, might be involved in G1/S transition. The binding of AKAP95 and LMW-E1 was found throughout cell cycle.
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Affiliation(s)
- Xiang-Yu Kong
- Department of Gastrointestinal Surgery, Affiliated Zhongshan Hospital of Dalian UniversityDalian Liaoning, 116001, China
| | - Deng-Cheng Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen UniversityXiamen Fujian, 361102, China
| | - Wen-Xin Zhuang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen UniversityXiamen Fujian, 361102, China
| | - Su-Hang Hua
- Department of Gastrointestinal Surgery, Affiliated Zhongshan Hospital of Dalian UniversityDalian Liaoning, 116001, China
| | - Yue Dai
- Department of Life Science and Bio-pharmaceutics, Shenyang Pharmaceutical UniversityShenyang Liaoning, 110015, China
| | - Yang-Yang Yuan
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen UniversityXiamen Fujian, 361102, China
| | - Li-Li Feng
- Department of Integrated TCM and Western Medicine, Beijing YouAn Hospital Affiliated with Capital Medical UniversityBeijing, 10069, China
| | - Qian Huang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen UniversityXiamen Fujian, 361102, China
| | - Bo-Gang Teng
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen UniversityXiamen Fujian, 361102, China
| | - Xiu-Yi Yu
- The First Affiliated Hospital of Xiamen UniversityXiamen Fujian, 361102, China
| | - Wen-Zhi Liu
- Department of Gastrointestinal Surgery, Affiliated Zhongshan Hospital of Dalian UniversityDalian Liaoning, 116001, China
| | - Yong-Xing Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen UniversityXiamen Fujian, 361102, China
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Chen M, Ni Y, Liu Y, Xia X, Cao J, Wang C, Mao X, Zhang W, Chen C, Chen X, Wang Y. Spatiotemporal Expression of EAPP Modulates Neuronal Apoptosis and Reactive Astrogliosis After Spinal Cord Injury. J Cell Biochem 2016; 116:1381-90. [PMID: 25704466 DOI: 10.1002/jcb.25096] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 01/23/2015] [Indexed: 11/11/2022]
Abstract
E2F-associated phosphoprotein (EAPP) is a novel E2F binding protein that interacts with the activating members of the E2F transcription factors family and involved in various biological processes. However, the expression and function of EAPP in central nervous system (CNS) are still unknown. In this study, we performed an acute spinal cord injury (SCI) model in adult rats, we found that EAPP protein levels were significantly increased and reached a peak at day 3, and then gradually returned to normal level at day 14 after spinal cord injury and we observed that the expression of EAPP is enhanced in the gray and white matter. Spatially, increased levels of EAPP were striking in neurons and astrocytes. Moreover, colocalization of EAPP/active caspase-3 was detected in neurons, and colocalization of EAPP/proliferating cell nuclear antigen (PCNA) was detected in astrocytes after spinal cord injury. These results indicated that EAPP might play an important role in neuronal apoptosis and reactive astrogliosis. Furthermore in vitro, EAPP depletion by siRNA inhibited astrocyte proliferation, migration and CDK4/cyclinD1 expression. Meanwhile, EAPP knockdown also reduce neuronal apoptosis and cell cycle related proteins. Which indicated that EAPP might integrate cell cycle progression and play a crucial role in cell proliferation and apoptosis. Taken together, we speculated that EAPP was involved in biochemical and physiological responses after SCI.
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Affiliation(s)
- Minhao Chen
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, Jiangsu, PR China
| | - Yingjie Ni
- Department of Orthopaedics, Xishan People' Hospital, Wuxi, Jiangsu, PR China
| | - Yonghua Liu
- Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College, Nantong University, Nantong, Jiangsu, PR China
| | - Xiaopeng Xia
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, Jiangsu, PR China
| | - Jianhua Cao
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, Jiangsu, PR China
| | - Chengniu Wang
- Basic Medical Research Centre, Medical School, Nantong University, Nantong, Jiangsu, PR China
| | - Xingxing Mao
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, Jiangsu, PR China
| | - Weidong Zhang
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, Jiangsu, PR China
| | - Chen Chen
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, Jiangsu, PR China
| | - Xinlei Chen
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, Jiangsu, PR China
| | - Youhua Wang
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, Jiangsu, PR China
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Peche LY, Ladelfa MF, Toledo MF, Mano M, Laiseca JE, Schneider C, Monte M. Human MageB2 Protein Expression Enhances E2F Transcriptional Activity, Cell Proliferation, and Resistance to Ribotoxic Stress. J Biol Chem 2015; 290:29652-62. [PMID: 26468294 DOI: 10.1074/jbc.m115.671982] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Indexed: 12/15/2022] Open
Abstract
MageB2 belongs to the melanoma antigen gene (MAGE-I) family of tumor-specific antigens. Expression of this gene has been detected in human tumors of different origins. However, little is known about the protein function and how its expression affects tumor cell phenotypes. In this work, we found that human MageB2 protein promotes tumor cell proliferation in a p53-independent fashion, as observed both in cultured cells and growing tumors in mice. Gene expression analysis showed that MageB2 enhances the activity of E2F transcription factors. Mechanistically, the activation of E2Fs is related to the ability of MageB2 to interact with the E2F inhibitor HDAC1. Cellular distribution of MageB2 protein includes the nucleoli. Nevertheless, ribotoxic drugs rapidly promote its nucleolar exit. We show that MageB2 counteracts E2F inhibition by ribosomal proteins independently of Mdm2 expression. Importantly, MageB2 plays a critical role in impairing cell cycle arrest in response to Actinomycin D. The data presented here support a relevant function for human MageB2 in cancer cells both under cycling and stressed conditions, presenting a distinct functional feature with respect to other characterized MAGE-I proteins.
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Affiliation(s)
- Leticia Y Peche
- From the Laboratorio Nazionale del Consorzio Interuniversitario per le Biotecnologie, Area Science Park, Padriciano 99, 34149 Trieste, Italy
| | - María F Ladelfa
- the Departamento de Química Biológica and Instituto de Química Biológica Ciencias Exactas y Naturales/Consejo de Investigaciones Científicas y Técnicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina
| | - María F Toledo
- the Departamento de Química Biológica and Instituto de Química Biológica Ciencias Exactas y Naturales/Consejo de Investigaciones Científicas y Técnicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina
| | - Miguel Mano
- the International Centre for Genetic Engineering and Biotechnology, Area Science Park, Padriciano 99, 34149 Trieste, Italy, and
| | - Julieta E Laiseca
- the Departamento de Química Biológica and Instituto de Química Biológica Ciencias Exactas y Naturales/Consejo de Investigaciones Científicas y Técnicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina
| | - Claudio Schneider
- From the Laboratorio Nazionale del Consorzio Interuniversitario per le Biotecnologie, Area Science Park, Padriciano 99, 34149 Trieste, Italy, the Dipartimento di Scienze e Tecnologie Biomediche, Università di Udine, p.le Kolbe 4, 33100 Udine, Italy
| | - Martín Monte
- the Departamento de Química Biológica and Instituto de Química Biológica Ciencias Exactas y Naturales/Consejo de Investigaciones Científicas y Técnicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina,
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Jiang W, Li YQ, Liu N, Sun Y, He QM, Jiang N, Xu YF, Chen L, Ma J. 5-Azacytidine enhances the radiosensitivity of CNE2 and SUNE1 cells in vitro and in vivo possibly by altering DNA methylation. PLoS One 2014; 9:e93273. [PMID: 24691157 PMCID: PMC3972231 DOI: 10.1371/journal.pone.0093273] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 03/04/2014] [Indexed: 12/31/2022] Open
Abstract
The radioresistance of tumor cells remains a major cause of treatment failure in nasopharyngeal carcinoma (NPC). Recently, several reports have highlighted the importance of epigenetic changes in radiation-induced responses. Here, we investigated whether the demethylating agent 5-azacytidine (5-azaC) enhances the radiosensitivity of NPC cells. The NPC cell lines CNE2 and SUNE1 were treated with 1 μmol/L 5-azaC for 24 h before irradiation (IR); clonogenic survival was then assessed. Tumor growth was investigated in a mouse xenograft model in vivo. The apoptosis, cell cycle progression and DNA damage repair were examined using flow cytometry, immunofluorescent staining and western blotting. Promoter methylation and the expression of four genes epigenetically silenced during the development of NPC were evaluated by pyrosequencing and real-time PCR. We found that pretreatment with 5-azaC significantly decreased clonogenic survival after IR compared to IR alone; the sensitivity-enhancement ratio of 5-azaC was 1.4 and 1.2 for CNE2 and SUNE1 cells, respectively. The combined administration of 5-azaC and IR significantly inhibited tumor growth in the mouse xenograft model, and enhanced radiation-induced apoptosis in vitro compared to 5-azaC alone or IR alone. 5-AzaC also decreased promoter methylation and upregulated the expression of genes which are epigenetically silenced both in vitro and in vivo in NPC. Thus, 5-azaC enhance the radiosensitivity of both the CNE2 and SUNE1 cell lines, possibly by altering DNA methylation levels and increasing the ability of irradiated cells to undergo apoptosis. The use of 5-azaC combined with IR maybe represent an attractive strategy for the treatment of NPC.
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Affiliation(s)
- Wei Jiang
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People’s Republic of China
| | - Ying-Qin Li
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People’s Republic of China
| | - Na Liu
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People’s Republic of China
| | - Ying Sun
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People’s Republic of China
| | - Qing-Mei He
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People’s Republic of China
| | - Ning Jiang
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People’s Republic of China
| | - Ya-Fei Xu
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People’s Republic of China
| | - Lei Chen
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People’s Republic of China
| | - Jun Ma
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, People’s Republic of China
- * E-mail:
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Abstract
UNLABELLED Lytic infection by herpesviruses induces cell cycle arrest at the G1/S transition. This appears to be a function of multiple herpesvirus proteins, but only a minority of herpesvirus proteins have been examined for cell cycle effects. To gain a more comprehensive understanding of the viral proteins that contribute to G1/S arrest, we screened a library of over 200 proteins from herpes simplex virus type 1, human cytomegalovirus, and Epstein-Barr virus (EBV) for effects on the G1/S interface, using HeLa fluorescent, ubiquitination-based cell cycle indicator (Fucci) cells in which G1/S can be detected colorimetrically. Proteins from each virus were identified that induce accumulation of G1/S cells, predominantly tegument, early, and capsid proteins. The identification of several capsid proteins in this screen suggests that incoming viral capsids may function to modulate cellular processes. The cell cycle effects of selected EBV proteins were further verified and examined for effects on p53 and p21 as regulators of the G1/S transition. Two EBV replication proteins (BORF2 and BMRF1) were found to induce p53 but not p21, while a previously uncharacterized tegument protein (BGLF2) was found to induce p21 protein levels in a p53-independent manner. Proteomic analyses of BGLF2-interacting proteins identified interactions with the NIMA-related protein kinase (NEK9) and GEM-interacting protein (GMIP). Silencing of either NEK9 or GMIP induced p21 without affecting p53 and abrogated the ability of BGLF2 to further induce p21. Collectively, these results suggest multiple viral proteins contribute to G1/S arrest, including BGLF2, which induces p21 levels likely by interfering with the functions of NEK9 and GMIP. IMPORTANCE Most people are infected with multiple herpesviruses, whose proteins alter the infected cells in several ways. During lytic infection, the viral proteins block cell proliferation just before the cellular DNA replicates. We used a novel screening method to identify proteins from three different herpesviruses that contribute to this block. Several of the proteins we identified had previously unknown functions or were structural components of the virion. Subsets of these proteins from Epstein-Barr virus were studied for their effects on the cell cycle regulatory proteins p53 and p21, thereby identifying two proteins that induce p53 and one that induces p21 (BGLF2). We identified interactions of BGLF2 with two human proteins, both of which regulate p21, suggesting that BGLF2 induces p21 by interfering with the functions of these two host proteins. Our study indicates that multiple herpesvirus proteins contribute to the cell proliferation block, including components of the incoming virions.
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Mechanisms of radiation toxicity in transformed and non-transformed cells. Int J Mol Sci 2013; 14:15931-58. [PMID: 23912235 PMCID: PMC3759894 DOI: 10.3390/ijms140815931] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 07/19/2013] [Accepted: 07/22/2013] [Indexed: 12/31/2022] Open
Abstract
Radiation damage to biological systems is determined by the type of radiation, the total dosage of exposure, the dose rate, and the region of the body exposed. Three modes of cell death—necrosis, apoptosis, and autophagy—as well as accelerated senescence have been demonstrated to occur in vitro and in vivo in response to radiation in cancer cells as well as in normal cells. The basis for cellular selection for each mode depends on various factors including the specific cell type involved, the dose of radiation absorbed by the cell, and whether it is proliferating and/or transformed. Here we review the signaling mechanisms activated by radiation for the induction of toxicity in transformed and normal cells. Understanding the molecular mechanisms of radiation toxicity is critical for the development of radiation countermeasures as well as for the improvement of clinical radiation in cancer treatment.
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Regulation of the MDR1 promoter by E2F1 and EAPP. FEBS Lett 2013; 587:1504-9. [PMID: 23542036 DOI: 10.1016/j.febslet.2013.03.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Revised: 03/14/2013] [Accepted: 03/17/2013] [Indexed: 11/22/2022]
Abstract
Multidrug resistance (MDR), one of the main reasons for diminishing efficacy of prolonged chemotherapy, is frequently caused by the elevated expression of the ABCB1/MDR1 gene encoding PGP (P-glycoprotein). EAPP (E2F Associated PhosphoProtein) is a frequently overexpressed protein in human tumor cells. It inhibits apoptosis in a p21-dependent manner. We show here that EAPP stimulates the MDR1 promoter resulting in higher PGP levels. Independently of EAPP, E2F1 also increases the activity of the MDR1 promoter. Co-expression of pRb inhibits E2F1-, but not EAPP-dependent promoter activation. The upregulation of PGP might contribute to the survival of tumor cells during chemotherapy and worsen the prognosis for the patient.
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E2F1 apoptosis counterattacked: evil strikes back. Trends Mol Med 2013; 19:89-98. [DOI: 10.1016/j.molmed.2012.10.009] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 10/23/2012] [Accepted: 10/23/2012] [Indexed: 12/15/2022]
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Wang X, Li S, Cao T, Fu X, Yu G. Evaluating biotoxicity with fibroblasts derived from human embryonic stem cells. Toxicol In Vitro 2012; 26:1056-63. [DOI: 10.1016/j.tiv.2012.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 02/19/2012] [Accepted: 04/04/2012] [Indexed: 12/28/2022]
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Andorfer P, Schwarzmayr L, Rotheneder H. EAPP modulates the activity of p21 and Chk2. Cell Cycle 2011; 10:2077-82. [PMID: 21572256 DOI: 10.4161/cc.10.13.16247] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Genomic instability is thought to be critical for the development of cancer. Among its causes microsatellite instability (MIN) and chromosomal instability (CIN) have attracted the most attention. Cell cycle checkpoints and DNA repair mechanisms are the first line of defense against DNA damage. Among the most dangerous DNA lesions are double-strand breaks. The response to DNA double strand breaks is regulated mainly by the serine/threonine kinases ATM and Chk2 and their downstream target the tumor suppressor p53, which in turn stimulates the expression of growth-inhibitory genes like p21 or pro-apoptotic genes like Bax. The balance between these gene products determines the fate of a cell. EAPP is a nuclear phosphoprotein that is frequently upregulated in human tumors. We have recently shown that EAPP levels are critical for cellular homeostasis. DNA damage elevates EAPP levels and its overexpression results in G1 arrest and impairs apoptosis in a p21-dependent manner. EAPP binds to the p21 promoter, stimulates its activity and seems to be essential for transcription initiation. In the present work we show that EAPP also regulates the phosphorylation status and thus the activity of Chk2. EAPP binding seems to trigger the dephosphorylation of P-Chk2 resulting in its inactivation. A newly described function of Chk2 in mitosis that secures genomic integrity might also be affected by EAPP overexpression. This might explain the abundance of EAPP in aneuploid tumor cells.
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Affiliation(s)
- Peter Andorfer
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
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