A high-throughput pharmaceutical screen identifies compounds with specific toxicity against BRCA2-deficient tumors.
A high-throughput pharmaceutical screen identifies compounds with specific toxicity against BRCA2-deficient tumors.
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DOI：
10.1158/1078-0432.ccr-09-2434
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发表时间：
2010-01-01
期刊：
影响因子：
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通讯作者：
Jonkers J
中科院分区：
文献类型：
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作者：
Evers B;Schut E;van der Burg E;Braumuller TM;Egan DA;Holstege H;Edser P;Adams DJ;Wade-Martins R;Bouwman P;Jonkers J
遗传性乳腺癌的部分原因是BRCA 1和BRCA 2的生殖系突变。虽然患者携带杂合突变，但他们的肿瘤通常丢失了剩余的野生型等位基因。因此，选择性靶向BRCA缺陷可能构成一种重要的治疗方法。应用这一原理的临床试验正在进行中，但尚不清楚测试的化合物是否是最佳的。因此，重要的是要确定专门针对BRCA缺陷的替代化合物，并测试新的联合疗法，以建立最佳的治疗策略。我们对BRCA 2缺陷小鼠乳腺肿瘤细胞和恢复BRCA 2功能的同基因对照进行了高通量药物筛选。随后，我们使用携带BRCA 2缺陷型乳腺肿瘤的小鼠在体外和体内验证了阳性命中。苯丁酸氮芥、美法仑和尼莫司汀三种烷化剂对BRCA 2缺陷细胞显示出强烈的特异性毒性。在体内，这些药物显示出异质性，但通常具有较强的BRCA 2缺陷型抗肿瘤活性，在这项小型研究中，美法仑和尼莫司汀优于顺铂和聚（ADP-核糖）聚合酶（PARP）抑制剂奥拉帕尼（AZD 2281）。体外药物组合实验显示了烷化剂和奥拉帕尼之间的协同相互作用。联合尼莫司汀和奥拉帕尼的肿瘤干预研究导致5只受试动物中有3只的无复发生存期超过330天。我们生成并验证了一个平台，用于鉴定对BRCA 2缺陷细胞具有特异性活性的化合物，该平台可以很好地转化为临床前环境。我们的数据要求重新评估烷化剂-特别是美法仑和尼莫司汀-单独或与PARP抑制剂联合治疗BRCA通路缺陷的乳腺癌。
Hereditary breast cancer is partly explained by germline mutations in BRCA1 and BRCA2. While patients carry heterozygous mutations, their tumors have typically lost the remaining wild-type allele. Selectively targeting BRCA-deficiency may therefore constitute an important therapeutic approach. Clinical trials applying this principle are underway, but it is unknown whether the compounds tested are optimal. It is therefore important to identify alternative compounds that specifically target BRCA-deficiency and to test new combination therapies to establish optimal treatment strategies. We performed a high-throughput pharmaceutical screen on BRCA2-deficient mouse mammary tumor cells and isogenic controls with restored BRCA2 function. Subsequently, we validated positive hits in vitro and in vivo using mice carrying BRCA2-deficient mammary tumors. Three alkylators – chlorambucil, melphalan and nimustine – displayed strong and specific toxicity against BRCA2-deficient cells. In vivo, these showed heterogeneous but generally strong BRCA2-deficient antitumor activity, with melphalan and nimustine outperforming cisplatin and the poly-(ADP-ribose)-polymerase (PARP) inhibitor olaparib (AZD2281) in this small study. In vitro drug combination experiments showed synergistic interactions between the alkylators and olaparib. Tumor intervention studies combining nimustine and olaparib resulted in recurrence-free survival exceeding 330 days in 3 out of 5 animals tested. We generated and validated a platform for identification of compounds with specific activity against BRCA2-deficient cells that translates well to the preclinical setting. Our data call for the re-evaluation of alkylators – especially melphalan and nimustine – alone or in combination with PARP inhibitors for the treatment of breast cancers with a defective BRCA pathway.