间皮瘤细胞对 PARP 抑制剂的敏感性不依赖于 BAP1，但在 Schlafen 11 高表达和 O6-甲基鸟嘌呤-DNA 甲基转移酶低表达的细胞中，替莫唑胺可增强其敏感性。
Sensitivity of Mesothelioma Cells to PARP Inhibitors Is Not Dependent on BAP1 but Is Enhanced by Temozolomide in Cells With High-Schlafen 11 and Low-O6-methylguanine-DNA Methyltransferase Expression.
机构信息
Thoracic and GI Malignancies Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
Developmental Therapeutics Branch, Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
出版信息
J Thorac Oncol. 2020 May;15(5):843-859. doi: 10.1016/j.jtho.2020.01.012. Epub 2020 Jan 28.
INTRODUCTION
BRCA1-associated protein-1 (BAP1), a nuclear deubiquitinase thought to be involved in DNA double-strand break repair, is frequently mutated in mesothelioma. Because poly(adenosine diphosphate-ribose) polymerase inhibitors (PARPIs) induce synthetic lethality in BRCA1/2 mutant cancers, we evaluated whether BAP1 inactivating mutations confer sensitivity to PARPIs in mesothelioma and if combination therapy with temozolomide (TMZ) would be beneficial.
METHODS
A total of 10 patient-derived mesothelioma cell lines were generated and characterized for BAP1 mutation status, protein expression, nuclear localization, and sensitivity to the PARPIs, olaparib, and talazoparib, alone or in combination with TMZ. BAP1 deubiquitinase (DUB) activity was evaluated by ubiquitin with 7-amido-4-methylcoumarin assay. BAP1 knockout mesothelioma cell lines were generated by CRISPR-Cas9. Because Schlafen 11 (SLFN11) and O-methylguanine-DNA methyltransferase also drive response to TMZ and PARPIs, we tested their expression and relationship with drug response.
RESULTS
BAP1 mutations or copy-number alterations, or both were present in all 10 cell lines. Nonetheless, four cell lines exhibited intact DUB activity and two had nuclear BAP1 localization. Half maximal-inhibitory concentrations of olaparib and talazoparib ranged from 4.8 μM to greater than 50 μM and 0.039 μM to greater than 5 μM, respectively, classifying them into sensitive (two) or resistant (seven) cells, independent of their BAP1 status. Cell lines with BAP1 knockout resulted in the loss of BAP1 DUB activity but did not increase sensitivity to talazoparib. Response to PARPI tended to be associated with high SLFN11 expression, and combination with temozolomide increased sensitivity of cells with low or no MGMT expression.
CONCLUSIONS
BAP1 status does not determine sensitivity to PARPIs in patient-derived mesothelioma cell lines. Combination of PARPI with TMZ may be beneficial for patients whose tumors have high SLFN11 and low or no MGMT expression.
简介
BRCA1 相关蛋白-1（BAP1）是一种核去泛素化酶，被认为参与 DNA 双链断裂修复，在间皮瘤中经常发生突变。由于聚（腺苷二磷酸核糖）聚合酶抑制剂（PARPIs）在 BRCA1/2 突变型癌症中诱导合成致死，我们评估了 BAP1 失活突变是否使间皮瘤对 PARPIs 敏感，以及与替莫唑胺（TMZ）联合治疗是否有益。
方法
共生成并表征了 10 种患者来源的间皮瘤细胞系，以确定 BAP1 突变状态、蛋白表达、核定位以及对 PARPIs（奥拉帕利和他拉唑帕利）单独或联合 TMZ 的敏感性。通过 7-氨基-4-甲基香豆素测定法评估 BAP1 去泛素化酶（DUB）活性。通过 CRISPR-Cas9 生成 BAP1 缺失的间皮瘤细胞系。由于 Schlafen 11（SLFN11）和 O-甲基鸟嘌呤-DNA 甲基转移酶也可驱动 TMZ 和 PARPIs 的反应，我们测试了它们的表达及其与药物反应的关系。
结果
所有 10 种细胞系均存在 BAP1 突变或拷贝数改变，或两者兼有。尽管如此，四种细胞系仍具有完整的 DUB 活性，两种细胞系具有核 BAP1 定位。奥拉帕利和他拉唑帕利的半最大抑制浓度范围分别为 4.8 μM 至大于 50 μM 和 0.039 μM 至大于 5 μM，分别将它们归类为敏感（两种）或耐药（七种）细胞，与 BAP1 状态无关。BAP1 缺失的细胞系导致 BAP1 DUB 活性丧失，但不能增加对他拉唑帕利的敏感性。对 PARPI 的反应倾向于与高 SLFN11 表达相关，与替莫唑胺联合使用可增加低表达或无 MGMT 表达的细胞的敏感性。
结论
BAP1 状态不能决定患者来源的间皮瘤细胞系对 PARPIs 的敏感性。PARPI 与 TMZ 的联合使用可能对 SLFN11 高表达和低表达或无 MGMT 表达的肿瘤患者有益。
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