Department of Toxicology, School of Public Health, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang 050017, Hebei, People's Republic of China; Department of Occupational and Environmental Health, School of Public Health, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang 050017, Hebei, People's Republic of China.
National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, 29 Nanwei Road, Xuanwu District, Beijing 100050, People's Republic of China.
Environ Toxicol Pharmacol. 2013 Sep;36(2):311-319. doi: 10.1016/j.etap.2013.04.009. Epub 2013 May 2.
γ-ray irradiation can induce DNA damages which include base damages, single-strand breaks and double-strand breaks in various type cells. The DNA repair protein XRCC1, as a part of the BER pathway, forms complexes with DNA polymerase beta, DNA ligase III and poly-ADP-ribose polymerase (PARP) in the repair of DNA single strand breaks and also affects the repair of double strand breaks. However, it is still not known well whether XRCC1 contributes to affect the irradiation sensitivity and DNA damage in HepG2 cell and the potential mechanism. Hence, the purpose of this study was to explore whether abrogation of XRCC1 gene expression by shRNA could reduce DNA repair and thus sensitize HepG2 cells to γ-ray. Cell viability was measured by Trypan blue staining and cloning efficiency assay. The DNA damage was detected by Comet assay. Apoptosis and cell cycle were detected by flow cytometry. The DNA-PKcs and gadd153 mRNA expression were determined by Real-time PCR. Our results showed that abrogation of XRCC 1 could sensitize HepG2 cells to γ-ray. This enhanced sensitivity could be attributed to the increased DNA damage and increased cell cycle arrest, which might be related with the increasing of DNA-PKcs and gadd153 mRNA expression. Therefore, our results suggested that the γ-ray irradiation sensitivity could be increased by targeting inhibition of XRCC1 in HepG2 cell.
γ 射线照射会诱导各种类型细胞中的 DNA 损伤，包括碱基损伤、单链断裂和双链断裂。DNA 修复蛋白 XRCC1 作为 BER 途径的一部分，在修复 DNA 单链断裂时与 DNA 聚合酶β、DNA 连接酶 III 和聚 ADP-核糖聚合酶（PARP）形成复合物，并且还影响双链断裂的修复。然而，目前尚不清楚 XRCC1 是否有助于影响 HepG2 细胞中的照射敏感性和 DNA 损伤以及潜在的机制。因此，本研究旨在探讨通过 shRNA 敲低 XRCC1 基因表达是否可以减少 DNA 修复，从而使 HepG2 细胞对 γ 射线敏感。通过台盼蓝染色和克隆效率测定法测量细胞活力。通过彗星试验检测 DNA 损伤。通过流式细胞术检测细胞凋亡和细胞周期。通过 Real-time PCR 测定 DNA-PKcs 和 gadd153 mRNA 的表达。我们的结果表明，敲低 XRCC1 可以使 HepG2 细胞对 γ 射线敏感。这种增强的敏感性可能归因于 DNA 损伤的增加和细胞周期停滞的增加，这可能与 DNA-PKcs 和 gadd153 mRNA 表达的增加有关。因此，我们的结果表明，通过靶向抑制 HepG2 细胞中的 XRCC1，可以提高 γ 射线照射的敏感性。
