KU70 Inhibition Impairs Both Non-Homologous End Joining and Homologous Recombination DNA Damage Repair Through SHP-1 Induced Dephosphorylation of SIRT1 in Adult T-Cell Leukemia-Lymphoma Cells.
KU70 Inhibition Impairs Both Non-Homologous End Joining and Homologous Recombination DNA Damage Repair Through SHP-1 Induced Dephosphorylation of SIRT1 in Adult T-Cell Leukemia-Lymphoma Cells.
复制标题
KU70 抑制通过 SHP-1 诱导成人 T 细胞白血病-淋巴瘤细胞中 SIRT1 去磷酸化，损害非同源末端连接和同源重组 DNA 损伤修复。
DOI：
10.1159/000493815
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发表时间：
2018
影响因子：
--
通讯作者：
Liang Aibin
中科院分区：
文献类型：
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作者：
Yu Wenlei;Li Liang;Wang Guangming;Zhang Wenjun;Xu Jun;Liang Aibin
成人T细胞白血病-淋巴瘤（ATL）是一种对化疗高度耐药的侵袭性疾病。研究表明，肿瘤细胞DNA损伤修复（DDR）能力的增强在化疗耐药中起着关键作用。方法利用KU 70在ATL最具代表性的细胞系之一Jurkat细胞中的高表达，采用shRNA技术敲低KU 70，通过Western blot、免疫荧光、免疫荧光、免疫组化等方法，分析KU 70缺陷对Jurkat细胞及NOD-SCID动物模型的影响，结果KU 70基因沉默导致Jurkat细胞DNA损伤和DDR损伤，导致细胞凋亡增加，细胞增殖下降，细胞周期阻滞。DNA损伤导致DNA双链断裂（DSB），其通过非同源末端连接（NHEJ）或同源重组（HR）进行处理。在我们的研究中，由于KU 70缺陷，NHEJ和HR均受损，并伴有去磷酸化酶SHP-1蛋白水平的增加。反过来，SHP-1导致SIRT 1的去磷酸化，这进一步损害了HR修复效率。此外，KU 70缺陷延长Jurkat异种移植mice.ConclusionThese研究结果表明，针对KU 70是一个有前途的目标ATL，并可能克服现有的化疗困难。
Background/AimsAdult T-cell leukemia-lymphoma (ATL) is an aggressive disease which is highly resistant to chemotherapy. Studies show that enhanced ability of DNA damage repair (DDR) in cancer cells plays a key role in chemotherapy resistance. Here, we suggest that defect in DDR related genes might be a promising target to destroy the genome stability of tumor cells.MethodsSince KU70 is highly expressed in Jurkat cells, one of the most representative cell lines of ATL, we knocked down KU70 by shRNA and analyzed the impact of KU70 deficiency in Jurkat cells as well as in NOD-SCID animal models by western blot, immunofluorescence, flow cytometry and measuring DNA repair efficiency.ResultsIt is observed that silencing of KU70 resulted in accumulated DNA damage and impaired DDR in Jurkat cells, resulting in more apoptosis, decreased cell proliferation and cell cycle arrest. DNA damage leads to DNA double-strand breaks (DSBs), which are processed by either non-homologous end joining (NHEJ) or homologous recombination (HR). In our study, both NHEJ and HR are impaired because of KU70 defect, accompanied with increased protein level of SHP-1, a dephosphorylation enzyme. In turn, SHP-1 led to dephosphorylation of SIRT1, which further impaired HR repair efficiency. Moreover, KU70 deficiency prolonged survival of Jurkat-xenografted mice.ConclusionThese findings suggest that targeting KU70 is a promising target for ATL and might overcome the existing difficulties in chemotherapy.