The ABL switch control inhibitor DCC-2036 is active against the chronic myeloid leukemia mutant BCR-ABLT315I and exhibits a narrow resistance profile.
The ABL switch control inhibitor DCC-2036 is active against the chronic myeloid leukemia mutant BCR-ABLT315I and exhibits a narrow resistance profile.
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DOI：
10.1158/0008-5472.can-10-3224
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发表时间：
2011-05-01
期刊：
影响因子：
11.2
通讯作者：
Druker BJ
中科院分区：
文献类型：
--
作者：
Eide CA;Adrian LT;Tyner JW;Mac Partlin M;Anderson DJ;Wise SC;Smith BD;Petillo PA;Flynn DL;Deininger MW;O'Hare T;Druker BJ
获得性BCR-ABL激酶结构域内的点突变代表慢性粒细胞白血病（CML）患者对ABL抑制剂治疗耐药的常见机制。BCR-ABLT 315 I突变体对伊马替尼、尼洛替尼和达沙替尼高度耐药，经常在复发患者中检出。耐药覆盖率的这一关键缺口推动了DCC-2036的开发，DCC-2036是一种ABL抑制剂，其结合参与激酶结构域构象调节的开关控制口袋。我们在细胞和生物化学测定中评估了DCC-2036对BCR-ABLT 315 I和其他突变体的功效，并进行了基于细胞的诱变筛选。DCC-2036抑制ABL和ABLT 315 I酶的自磷酸化，该活性与对表达BCR-ABL（IC 50：19 nmol/L）、BCR-ABLT 315 I（IC 50：63 nmol/L）和大多数激酶结构域突变体的Ba/F3细胞的选择性疗效一致。将携带BCR-ABL或BCR-ABLT 315 I的患者的CML细胞离体暴露于DCC-2036，显示集落形成受到显著抑制，直接BCR-ABL靶点CrkL的磷酸化水平降低。基于细胞的诱变筛选鉴定了DCC-2036的抗性谱，其集中在选择的P环突变（G250 E、Q252 H、Y253 H、E255 K/V）周围，尽管750 nmol/L DCC-2036的浓度抑制了所有抗性克隆的出现。DCC-2036浓度降低（160 nmol/L）与尼洛替尼或达沙替尼的双重组合实现了相同的零生长结果。进一步筛选由于BCR-ABL化合物突变（同一克隆中的两个突变）引起的耐药性，将BCR-ABLE 255 V/T315 I鉴定为耐药性最强的突变体。总之，这些发现支持继续评价DCC-2036作为治疗难治性CML的重要新药。
Acquired point mutations within the BCR-ABL kinase domain represent a common mechanism of resistance to ABL inhibitor therapy in patients with chronic myeloid leukemia (CML). The BCR-ABLT315I mutant is highly resistant to imatinib, nilotinib, and dasatinib and is frequently detected in relapsed patients. This critical gap in resistance coverage drove development of DCC-2036, an ABL inhibitor which binds the switch control pocket involved in conformational regulation of the kinase domain. We evaluated the efficacy of DCC-2036 against BCR-ABLT315I and other mutants in cellular and biochemical assays and conducted cell-based mutagenesis screens. DCC-2036 inhibited autophosphorylation of ABL and ABLT315I enzymes, and this activity was consistent with selective efficacy against Ba/F3 cells expressing BCR-ABL (IC50: 19 nmol/L), BCR-ABLT315I (IC50: 63 nmol/L), and most kinase domain mutants. Ex vivo exposure of CML cells from patients harboring BCR-ABL or BCR-ABLT315I to DCC-2036 revealed marked inhibition of colony formation and reduced phosphorylation of the direct BCR-ABL target CrkL. Cell-based mutagenesis screens identified a resistance profile for DCC-2036 centered around select P-loop mutations (G250E, Q252H, Y253H, E255K/V), although a concentration of 750 nmol/L DCC-2036 suppressed the emergence of all resistant clones. A decreased concentration of DCC-2036 (160 nmol/L) in dual-combination with either nilotinib or dasatinib achieved the same zero outgrowth result. Further screens for resistance due to BCR-ABL compound mutations (two mutations in the same clone) identified BCR-ABLE255V / T315I as the most resistant mutant. Taken together, these findings support continued evaluation of DCC-2036 as an important new agent for treatment-refractory CML.