|
|
|
| Effect of hexavalent chromium-induced ribosomal DNA copy number variation on DNA damage response in various cell lines |
| WU Fan1, FENG Lingfang1, CHEN Junfei1, JIANG Zhaoqiang1, GONG Xiaoxue1, QIN Yao1, LOU Jianlin2
|
1. School of Public Health, Hangzhou Medical College, Hangzhou, Zhejiang 310013, China;
2. Huzhou University, Huzhou, Zhejiang 313000, China |
|
|
|
|
Abstract Objective To investigate the effect of ribosomal DNA (rDNA) copy number variation caused by hexavalent chromium exposure on DNA damage response in different cell lines, so as to provide insights into the involvement of hexavalent chromium-induced rDNA copy number variation in DNA damage responses. Methods Human lung epithelial BEAS-2B cells and human embryonic lung MRC-5 cells were treated with 2 μmol/L potassium dichromate for 24 hours, and then cells were transferred to fresh media for further incubation, while cells treated with the same volume of phosphate buffer solution served as controls. Cells treated with potassium dichromate for 24 hours, and 3 and 7 days post-detoxification, were harvested, and rDNA copy number was quantified in cells using a quantitative fluorescent real-time PCR assay. Cell cycle, apoptosis and DNA damage were detected using a Muse cell analyzer, and the DNA damage was evaluated with the proportion of ataxia telangiectasia-mutated (ATM) gene activation, proportion of double-strand DNA breaks and the percentage of the H2A.X variant histone phosphorylatio. Results The 45S and 5S rDNA copy numbers of were significantly higher in MRC-5 cells than in BEAS-2B cells [(1.54±0.26) vs. (1.02±0.18), P<0.05; (6.97±1.07) vs. (3.00±0.15), P<0.05]. The 45S rDNA copy number was lower in MRC-5 cells 3 days post-detoxification (0.80±0.04) than in controls (P<0.05), and was higher in BEAS-2B cells 3 days post-detoxification (1.43±0.07) than in controls (P<0.05) . G0/G1 phase arrest was found in MRC-5 cells 24 hours post-treatment, and the apoptotic rates were significantly higher in MRC-5 cells 3 and 7 days post-detoxification than in controls [(11.53±1.53)%, (18.33±0.70)% vs. (3.53±0.93)%, P<0.05]. The overall apoptotic rates 24 hours post-treatment and 3 days post-detoxification [(2.80±0.17)%, (3.33±0.57)% vs. (1.53±0.61)%, P<0.05], proportion of ATM gene activation 3 days post-detoxification [(3.37±0.67%) vs. (1.18±0.22)%, P<0.05], proportion of double-strand DNA breaks 3 days post-detoxification [(4.45±0.85)% vs. (0.97±0.21)%, P<0.05] and percentage of the H2A.X variant histone phosphorylation 3 days post-detoxification [(1.68±0.56)% vs. (0.29±0.06)%, P<0.05] in BEAS-2B cells were higher than in controls. Conclusions Hexavalent chromium-induced rDNA copy number variation affects DNA damage response in different cell lines. A stronger DNA damage response is found in BEAS-2B cells with a low rDNA copy number, and a relative stable response is observed in MRC-5 cells with a high rDNA copy number.
|
|
Received: 08 February 2023
Revised: 31 March 2023
Published: 15 May 2023
|
|
|
|
|
|
[1] 郭心念,童延,贾君麟,等.六价铬对职业人群细胞周期相关基因表达的影响[J].预防医学,2017,29(7):670-674.
[2] NOVOTNIK B,ŠČANČAR J,MILAČIČ R,et al.Cytotoxic and genotoxic potential of Cr(Ⅵ),Cr(Ⅲ)-nitrate and Cr(Ⅲ)-EDTA complex in human hepatoma(HepG2)cells[J].Chemosphere,2016,154:124-131.
[3] WELLING R,BEAUMONT J J,PETERSEN S J,et al.Chromium Ⅵ and stomach cancer:a meta-analysis of the current epidemiological evidence[J].Occup Environ Med,2015,72(2):151-159.
[4] HESSEL E V S,STAAL Y C M,PIERSMA A H,et al.Occupational exposure to hexavalent chromium.Part I.Hazard assessment of non-cancer health effects[J/OL].Regul Toxicol Pharmacol,2021,126[2023-03-31] .https://europepmc.org/article/MED/34563613.DOI:10.1016/j.yrtph.2021.105048.
[5] 朱瑞瑞,李宁宁,贾光,等.六价铬致肺癌作用机制研究进展[J].中国公共卫生,2023,39(2):181-185.
[6] LOU J,YU S,FENG L,et al.Environmentally induced ribosomal DNA(rDNA)instability in human cells and populations exposed to hexavalent chromium[Cr(VI)][J/OL].Environ Int,2021,153[2023-03-31] .https://doi.org/10.1016/j.envint.2021.106525.
[7] WARMERDAM D O,WOLTHUIS R M F.Keeping ribosomal DNA intact:a repeating challenge[J].Chromosome Res,2019,27(1/2):57-72.
[8] NELSON J O,WATASE G J,WARSINGER-PEPE N,et al.Mechanisms of rDNA copy number maintenance[J].Trends Genet,2019,35(10):734-742.
[9] MALINOVSKAYA E M,ERSHOVA E S,GOLIMBET V E,et al.Copy number of human ribosomal genes with aging:unchanged mean,but narrowed range and decreased variance in elderly group[J/OL].Front Genet,2018,9[2023-03-31] .https://doi.org/10.3389/fgene.2018.00306.
[10] DONG C,AN L,YU C H,et al.A DYRK1B-dependent pathway suppresses rDNA transcription in response to DNA damage[J].Nucleic Acids Res,2021,49(3):1485-1496.
[11] WANG M,LEMOS B.Ribosomal DNA copy number amplification and loss in human cancers is linked to tumor genetic context,nucleolus activity,and proliferation[J/OL].PLoS Genet,2017,13(9)[2023-03-31] .https://doi.org/10.1371/journal.pgen.1006994.
[12] GIBBONS J G,BRANCO A T,GODINHO S A,et al.Concerted copy number variation balances ribosomal DNA dosage in human and mouse genomes[J].Proc Natl Acad Sci USA,2015,112(8):2485-2490.
[13] GE X,LI M,SONG G X,et al.Chromium(Ⅵ)-induced ALDH1A1/EGF axis promotes lung cancer progression[J/OL].Clin Transl Med,2022,12(12)[2023-03-31] .https://doi.org/10.1002/ctm2.1136.
[14] 贾君麟,楼建林.核糖体DNA在DNA损伤反应中的作用机制研究进展[J].中华劳动卫生职业病杂志,2018,36(1):70-74.
[15] JACKSON S P,BARTEK J.The DNA-damage response in human biology and disease[J].Nature,2009,461(7267):1071-1078.
[16] GIBBONS J G,BRANCO A T,YU S,et al.Ribosomal DNA copy number is coupled with gene expression variation and mitochondrial abundance in humans[J/OL].Nat Commun,2014,5[2023-03-31] .https://doi.org/10.1038/ncomms5850.
[17] PROKOPOWICH C D,GREGORY T R,CREASE T J.The correlation between rDNA copy number and genome size in eukaryotes[J].Genome,2003,46(1):48-50.
[18] 刘佳琪,冯玲芳,陈俊斐,等.温石棉暴露诱发核糖体DNA拷贝数变异及DNA损伤反应研究[J].预防医学,2022,34(6):547-554.
[19] XIAO J,LIU M,QI Y,et al.Structural insights into the activation of ATM kinase[J].Cell Res,2019,29(8):683-685.
[20] SMIRNOV E,CHMÚRČIAKOVÁ N,CMARKO D.Human rDNA and cancer[J/OL].Cells,2021,10(12)[2023-03-31] .https://doi.org/10.3390/cells10123452. |
|
|
|
