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Tang S, Liu B, Liu M, Li Z, Liu J, Wang H, Wang J, Oh YT, Shen L, Wang Y. Ionizing radiation-induced growth in soft agar is associated with miR-21 upregulation in wild-type and DNA double strand break repair deficient cells. DNA Repair (Amst) 2019; 78:37-44. [PMID: 30954901 DOI: 10.1016/j.dnarep.2019.03.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/21/2019] [Accepted: 03/22/2019] [Indexed: 12/19/2022]
Abstract
DNA double strand breaks (DSBs) are a severe threat to genome integrity and a potential cause of tumorigenesis, which is a multi-stage process and involves many factors including the mutation of oncogenes and tumor suppressors, some of which are transcribed microRNAs (miRNAs). Among more than 2000 known miRNAs, miR-21 is a unique onco-miRNA that is highly expressed in almost all types of human tumors and is associated with tumorigenesis through its multiple targets. However, it remains unclear whether there is any functional link between DSBs and miR-21 expression and, if so, does the link contribute to DSB-induced genomic instability/tumorigenesis. To address this question, we used DNA-PKcs-/- (deficient in non-homologous end-joining (NHEJ)) and Rad54-/- (deficient in homologous recombination repair (HRR)) mouse embryonic fibroblasts (MEFs) since NHEJ and HRR are the major pathways for DSB repair in mammalian cells. Our results indicate that levels of miR-21 are elevated in these DSB repair (DSBR) deficient cells, and ionizing radiation (IR) further increases these levels in both wild-type (WT) and DSBR-deficient cells. Interestingly, IR stimulated growth in soft agar and this effect was greatly reduced by blocking miR-21 expression in both WT and DSBR-deficient cells. Taken together, our results suggest that either IR or DSBR-deficient can lead to an upregulation of miR-21 levels and that miR-21 is associated with IR-induced cell growth in soft agar. These results may help our understanding of DSB-induced tumorigenesis and provide information that could facilitate the development of new strategies to prevent DSB-induced carcinogenesis.
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Affiliation(s)
- Siyuan Tang
- Department of Radiation Oncology, Emory University School of Medicine, Winship Cancer Institute of Emory University, Atlanta, GA, United States; Department of Oncology, Xiangya Hospital, Central South University, Changsha, China
| | - Bailong Liu
- Department of Radiation Oncology, Emory University School of Medicine, Winship Cancer Institute of Emory University, Atlanta, GA, United States; Department of Oncology, The First Norman Bethune Hospital of Jilin University, Changchun, China
| | - Min Liu
- Department of Radiation Oncology, Emory University School of Medicine, Winship Cancer Institute of Emory University, Atlanta, GA, United States; Department of Oncology, The First Norman Bethune Hospital of Jilin University, Changchun, China
| | - Zhentian Li
- Department of Radiation Oncology, Emory University School of Medicine, Winship Cancer Institute of Emory University, Atlanta, GA, United States
| | - Jiaqi Liu
- Department of Radiation Oncology, Emory University School of Medicine, Winship Cancer Institute of Emory University, Atlanta, GA, United States
| | - Hongyan Wang
- Department of Radiation Oncology, Emory University School of Medicine, Winship Cancer Institute of Emory University, Atlanta, GA, United States
| | - Jian Wang
- Department of Radiation Oncology, Emory University School of Medicine, Winship Cancer Institute of Emory University, Atlanta, GA, United States
| | - You-Take Oh
- Department of Radiation Oncology, Emory University School of Medicine, Winship Cancer Institute of Emory University, Atlanta, GA, United States
| | - Liangfang Shen
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, China.
| | - Ya Wang
- Department of Radiation Oncology, Emory University School of Medicine, Winship Cancer Institute of Emory University, Atlanta, GA, United States.
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