Radiation-induced DNA damage and altered expression of p21, cyclin D1 and Mre11 genes in human fibroblast cell lines with different radiosensitivity

IF 1.5 4区医学 Q4 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Mutation Research-Fundamental and Molecular Mechanisms of Mutagenesis Pub Date : 2021-07-01 DOI:10.1016/j.mrfmmm.2021.111760

Mohammad-Taghi Bahreyni-Toossi , Hosein Azimian , Seyed Hamid Aghaee-Bakhtiari , Mahmoud Mahmoudi , Mahdi Sadat- Darbandi , Navid Zafari

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引用次数: 4

Abstract

Purpose

Radiotherapy plays a pivotal role in the treatment of cancer. One of the main challenges in this treatment modality is radiation-induced complications in some patients affected by high radiosensitivity (RS). The differences in RS are determined mainly by genetic factors. Therefore, identifying the genes and mechanisms that affect RS in different cells is essential for evaluating radiotherapy outcomes. In the present study, the ability to repair DNA double-stranded breaks (DSB) is evaluated, followed by examining the expression levels of CDKN1A (p21), cyclinD1, and Mre11 genes in human fibroblasts with different RSs.

Materials & methods

Cellular RS was measured by survival fraction at 2 Gy (SF2). The γ-H2AX assay was used for assessing DNA repair capacity. Eventually, gene expression levels from each cell line 4 and 24 h after irradiation (at 2, 4, and 8 Gy) were measured by real-time PCR.

Results

The SF2 values for the cell lines ranged from 0.286 to 0.641, and RS differences of fibroblast cells were identified. Among the studied genes, the expression of Mre11 was the most important. Analysis of the real-time PCR data showed that changes in Mre11 gene expression (4 h after 8 Gy irradiation) were directly correlated with the RS (R² = 0.905). The difference in the expression of the p21 gene (4 h after 4 Gy irradiation) was also promising. Finally, the flow cytometry analysis showed that the radioresistant cell lines quickly repaired DBS damages. However, the repair process was slow in the radiosensitive cell line, and the residual damage is significantly higher than other cell lines (P < 0.01).

Conclusions

This study indicates that changes in the expression of p21 and Mre11 genes play an important role in cell response to radiation and thus these genes can be introduced as biomarkers to predict RS in normal cell lines.

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不同放射敏感性人成纤维细胞DNA损伤及p21、cyclin D1和Mre11基因表达改变

目的放射治疗在癌症治疗中起着举足轻重的作用。这种治疗方式的主要挑战之一是一些高放射敏感性(RS)患者的辐射引起的并发症。RS的差异主要由遗传因素决定。因此，确定影响不同细胞RS的基因和机制对于评估放疗结果至关重要。在本研究中，我们评估了修复DNA双链断裂(DSB)的能力，随后检测了不同RSs的人成纤维细胞中CDKN1A (p21)、cyclinD1和Mre11基因的表达水平。材料,方法采用存活分数法测定2 Gy (SF2)下细胞RS。采用γ-H2AX法评估DNA修复能力。最后，通过实时荧光定量PCR检测辐照(2、4和8 Gy)后4和24 h各细胞系的基因表达水平。结果成纤维细胞的SF2值在0.286 ~ 0.641之间，存在RS差异。在研究的基因中，Mre11的表达最为重要。实时PCR数据分析显示，Mre11基因表达变化(8 Gy辐照后4 h)与RS直接相关(R2 = 0.905)。p21基因的表达差异(4gy辐照后4小时)也很有希望。最后，流式细胞术分析显示，耐辐射细胞系能快速修复DBS损伤。然而，放射敏感细胞系的修复过程较慢，残余损伤明显高于其他细胞系(P <0.01)。结论p21和Mre11基因的表达变化在细胞对辐射的反应中起重要作用，可以作为预测正常细胞系RS的生物标志物。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Mutation Research-Fundamental and Molecular Mechanisms of Mutagenesis 生物-毒理学

CiteScore

4.90

自引率

0.00%

发文量

审稿时长

51 days

期刊介绍： Mutation Research (MR) provides a platform for publishing all aspects of DNA mutations and epimutations, from basic evolutionary aspects to translational applications in genetic and epigenetic diagnostics and therapy. Mutations are defined as all possible alterations in DNA sequence and sequence organization, from point mutations to genome structural variation, chromosomal aberrations and aneuploidy. Epimutations are defined as alterations in the epigenome, i.e., changes in DNA methylation, histone modification and small regulatory RNAs. MR publishes articles in the following areas: Of special interest are basic mechanisms through which DNA damage and mutations impact development and differentiation, stem cell biology and cell fate in general, including various forms of cell death and cellular senescence. The study of genome instability in human molecular epidemiology and in relation to complex phenotypes, such as human disease, is considered a growing area of importance. Mechanisms of (epi)mutation induction, for example, during DNA repair, replication or recombination; novel methods of (epi)mutation detection, with a focus on ultra-high-throughput sequencing. Landscape of somatic mutations and epimutations in cancer and aging. Role of de novo mutations in human disease and aging; mutations in population genomics. Interactions between mutations and epimutations. The role of epimutations in chromatin structure and function. Mitochondrial DNA mutations and their consequences in terms of human disease and aging. Novel ways to generate mutations and epimutations in cell lines and animal models.