Acute Leukemia in the Elderly: Development of Novel, Targeted Therapeutics

老年人急性白血病：新型靶向治疗药物的开发

• 批准号: 7732152
• 负责人: Dan Longo
• 金额: $ 36.61万
• 依托单位: NATIONAL INSTITUTE ON AGING
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7732152
• 关键词: Acute; Acute Myelocytic Leukemia; Acute leukemia; Adult Acute Lymphocytic Leukemia; Age; Alkylating Agents; Apoptosis; B-Lymphocytes; Base Excision Repairs; Biological Assay; Cell Line; Cell Proliferation; Cells; Cultured Cells; DNA Double Strand Break; DNA Repair; DNA Single Strand Break; DNA glycosylase; Data; Development; Drug Combinations; Elderly; Exhibits; Goals; Histone Deacetylase Inhibitor; Human; In Vitro; Incubated; Inhibition of Cell Proliferation; MGMT gene; Modeling; PARP inhibition; Pathway interactions; Patients; Pharmaceutical Preparations; Phase; Physiologic pulse; Pulse taking; Research; Resistance; Screening procedure; Site; Testing; Therapeutic; Topoisomerase-I Inhibitor; Topoisomerase-II Inhibitor; Topotecan; Trichostatin A; adduct; chemotherapeutic agent; homologous recombination; human APEX1 protein; inhibitor/antagonist; killings; leukemia; novel; novel therapeutics; outcome forecast; repaired; research study; temozolomide; therapeutic target

Despite therapeutic advances, treatment of adult ALL results in long term survival of only 30-40% of patients, with a significantly worse prognosis for patients over the age of 60. We have examined the activity of ABT-888, a potent inhibitor of PARP-1 and -2, in combination with several chemotherapeutic agents against a panel of human ALL and AML cell lines. No enhanced killing was noted when ABT-888 was combined with VP-16 (topoisomerase II inhibitor), trichostatin A (histone deacetylase inhibitor), or cloretazine (alkylating agent). However, synergistic killing of ALL (but not AML) was observed when ABT-888 was combined with the topoisomerase I inhibitor topotecan, and to a greater extent with combination of ABT-888 and temozolomide as determined in a 48h WST-1 screening assay using temozolomide at concentrations from 1-200 microM combined with ABT-888 (5 microM). The pre-B ALL lines Reh, RS4;11, and SUP-B15 were all very resistant to temozolomide alone with IC50s > 200 microM, consistent with the high levels of MGMT expressed by these cell lines. Culture in ABT-888 alone did not inhibit cell proliferation. However, when pre-B ALL cells were incubated for 30 or 60 minutes in clinically achievable concentrations of temozolomide (50-100 microM), washed, and then cultured for 48h in the presence of ABT-888 (5 microM), the IC50s for the combination were 25-50 microM, demonstrating a dramatic synergy for this combination in B-lineage ALL. Interestingly, AML cell lines pulsed in temozolomide and then cultured in ABT-888 as described above showed no inhibition of cell proliferation. Pre-B ALL cells cultured in temozolomide + ABT-888, but not either drug alone, arrested in S-phase and subsequently underwent apoptosis. Increased levels of gamma-H2AX foci were noted in combination-treated cells, and this occurred prior to the onset of apoptosis as determined by PARP cleavage. These data are consistent with a model in which single strand DNA breaks are generated at sites of temozolomide-induced N3-methyladenine adducts due to the actions of DNA glycosylase and APE1, however further repair via the base excision repair (BER) pathway is precluded by PARP inhibition. This leads to double strand DNA breaks during S-phase upon replication fork collapse and subsequent apoptosis. We hypothesize that while AML cells can repair DNA breaks using homologous recombination pathways which resolve dsDNA breaks, pre-B cells are relatively deficient in this pathway and thus exhibit selective sensitivity to this drug combination (synthetic lethal relationship). Experiments are underway to test this hypothesis. The in vitro results predict that the combination of temozolomide + ABT-888 could be an effective new treatment for adult ALL.

尽管有治疗性的进展，但对成人的治疗都导致长期存活仅为30-40％的患者，对60岁以上的患者的患者预后明显较差。我们检查了ABT-888的活性PARP-1和-2的有效抑制剂，这是一种有效的抑制剂，与几种化学司司机结合使用了All and All and All and All and All and All和Aml Cell系列。当将ABT-888与VP-16（拓扑异构酶II抑制剂），Trichostatin A（组蛋白脱乙酰基酶抑制剂）或氯酸吡嗪（烷基化剂）结合使用时，没有发现增强的杀伤。然而，当将ABT-888与拓扑异构酶I抑制剂替克蛋白替克蛋白替克（Topotecan）结合时，观察到所有（但不是AML）的协同杀戮，并且在48H WST-WST-1筛查中使用temozolomide在1-200微米组合中与ABT-OBT-OBTINED OBTINED EABTINESS确定的ABT-888和Temozolomide（abt-888和Temozolomide）结合更大程度地结合了ABT-1筛选分析。 Pre-B所有线REH，RS4; 11和SUP-B15都非常耐替莫唑胺，IC50> 200 microM，与这些细胞系表达的高水平MGMT一致。仅ABT-888中的培养不会抑制细胞增殖。但是，当Pre-B在临床上可达到的替莫唑胺（50-100 microM）中孵育30或60分钟时，洗涤并在ABT-888（5 microM）存在下进行48H培养，与此组合的IC50s为25-50 microM，表现为这种与此组合的巨大组合，以blineage in Blineage All bineaege All。有趣的是，如上所述，在替莫唑胺中脉动并在ABT-888中培养的AML细胞系未显示细胞增殖的抑制作用。 PER-B所有在替莫唑胺 + ABT-888中培养的细胞，但并非单独使用任何药物，在S期间被捕，随后经过凋亡。在组合处理的细胞中发现了γ-H2AX灶的水平升高，这发生在通过PARP裂解确定的凋亡开始之前。这些数据与一个模型一致，在该模型中，由于DNA糖基化酶和APE1的作用，在替莫唑胺诱导的N3-甲基趋化胺加合物的位点产生了单链DNA断裂，但是通过PARP抑制，通过碱基切除修复（BER）途径进一步修复。这会导致在复制叉塌陷和随后的凋亡后S期期间双链DNA断裂。我们假设，尽管AML细胞可以使用解决DSDNA断裂的同源重组途径来修复DNA断裂，但前B细胞在该途径中相对缺乏，因此对该药物组合表现出选择性的敏感性（合成致命关系）。正在进行测试该假设的实验。体外结果预测，替莫唑胺 + ABT-888的组合可能是成年人的有效新疗法。