Inhibition of Rad51 sensitizes breast cancer cells with wild-type PTEN to olaparib
Inhibition of Rad51 sensitizes breast cancer cells with wild-type PTEN to olaparib
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Rad51 的抑制使野生型 PTEN 乳腺癌细胞对奥拉帕尼敏感。
DOI：
10.1016/j.biopha.2017.07.090
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发表时间：
2017-10-01
影响因子：
7.5
通讯作者：
Mao, Weifeng
中科院分区：
文献类型：
--
作者：
Zhao, Qian;Guan, Jiawei;Mao, Weifeng
PTEN是一种肿瘤抑制基因，其特征在于是一种磷酸酶。然而，越来越多的证据表明，PTEN在DNA修复中的功能不依赖于其磷酸酶活性，这影响了DNA损伤抗肿瘤药物治疗具有PTEN变异的癌细胞的疗效。使用BT549乳腺癌细胞，我们研究了PTEN在DNA修复和乳腺癌细胞对olaparib（一种聚（ADP-核糖）聚合酶（PARP）抑制剂）的敏感性中的作用。彗星试验表明，PTEN促进DNA修复。PTEN缺陷型BT549细胞对奥拉帕尼敏感，这显示了PTEN和PARP 1之间的合成致死性。我们在BT549细胞中表达了PTEN，并且发现富含PTEN的BT549细胞对奥拉帕尼具有抗性。Western blot结果显示，PTEN可上调Rad 51的表达，提示PTEN通过Rad 51依赖的同源重组促进DNA修复。我们分别使用5 μ M奥拉帕尼或5 μ M RI-1（一种Rad 51抑制剂）处理PTEN-精通型BT549细胞。免疫荧光分析显示，奥拉帕尼和RI-1的组合诱导的γ H2 AX灶比它们中的任何一个多4倍。MTT分析显示5 μ M RI-1不改变PTEN-精通型BT549细胞的存活，然而，该剂量的RI-1使PTEN-精通型BT549细胞对奥拉帕尼敏感。因此，这些结果表明，Rad 51的抑制可以使具有野生型PTEN的BT549细胞对奥拉帕尼敏感，这将有助于在具有PTEN变异的乳腺癌患者的个体化治疗中使用PARP抑制剂。(C)2017 Elsevier Masson SAS。All rights reserved.
PTEN is a tumor suppressor gene well characterized as a phosphatase. However, more evidences demonstrate PTEN functions in DNA repair independent of its phosphatase activity, which affects the efficacy of DNA damage anti-tumoral drugs in treating cancer cells with PTEN variations. Using BT549 breast cancer cells, we studied the roles of PTEN in DNA repair and in sensitization of breast cancer cells to olaparib, a poly(ADP-ribose) polymerase (PARP) inhibitor. Comet assay showed PTEN promoted DNA repair. PTEN-deficient BT549 cells are sensitive to olaparib, which shows the synthetic lethality between PTEN and PARP1. We expressed PTEN in BT549 cells and found PTEN-proficient BT549 cells resist to olaparib. Western blot showed that PTEN up-regulated Rad51 expression, suggesting PTEN promotes DNA repair through Rad51-dependnent homologous recombination. We used 5 mu M olaparib or 5 mu M RI-1, a Rad51 inhibitor, to treat PTEN-proficient BT549 cells respectively. The immunofluorescent analysis showed the combination of olaparib and RI-1 induced more than 4-fold of gamma H2AX foci than either of them. MTT assay showed 5 mu M RI-1 did not change the survival of PTEN-proficient BT549 cells, however, this dose of RI-1 sensitized PTEN-proficient BT549 cells to olaparib. Consequently, these results demonstrate that inhibition of Rad51 can sensitize BT549 cells with wild type PTEN to olaparib, which would contribute to using PARP inhibitors in individual treatment of breast cancer patients with PTEN variations. (C) 2017 Elsevier Masson SAS. All rights reserved.