通过 mTOR 和自噬抑制靶向慢性髓性白血病中的 BCR-ABL 独立 TKI 耐药性。
Targeting BCR-ABL-Independent TKI Resistance in Chronic Myeloid Leukemia by mTOR and Autophagy Inhibition.
机构信息
Wolfson Wohl Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Glasgow, UK.
Paul O'Gorman Leukaemia Research Centre, Institute of Cancer Sciences, University of Glasgow, Glasgow, UK.
出版信息
J Natl Cancer Inst. 2018 May 1;110(5):467-478. doi: 10.1093/jnci/djx236.
BACKGROUND
Imatinib and second-generation tyrosine kinase inhibitors (TKIs) nilotinib and dasatinib have statistically significantly improved the life expectancy of chronic myeloid leukemia (CML) patients; however, resistance to TKIs remains a major clinical challenge. Although ponatinib, a third-generation TKI, improves outcomes for patients with BCR-ABL-dependent mechanisms of resistance, including the T315I mutation, a proportion of patients may have or develop BCR-ABL-independent resistance and fail ponatinib treatment. By modeling ponatinib resistance and testing samples from these CML patients, it is hoped that an alternative drug target can be identified and inhibited with a novel compound.
METHODS
Two CML cell lines with acquired BCR-ABL-independent resistance were generated following culture in ponatinib. RNA sequencing and gene ontology (GO) enrichment were used to detect aberrant transcriptional response in ponatinib-resistant cells. A validated oncogene drug library was used to identify US Food and Drug Administration-approved drugs with activity against TKI-resistant cells. Validation was performed using bone marrow (BM)-derived cells from TKI-resistant patients (n = 4) and a human xenograft mouse model (n = 4-6 mice per group). All statistical tests were two-sided.
RESULTS
We show that ponatinib-resistant CML cells can acquire BCR-ABL-independent resistance mediated through alternative activation of mTOR. Following transcriptomic analysis and drug screening, we highlight mTOR inhibition as an alternative therapeutic approach in TKI-resistant CML cells. Additionally, we show that catalytic mTOR inhibitors induce autophagy and demonstrate that genetic or pharmacological inhibition of autophagy sensitizes ponatinib-resistant CML cells to death induced by mTOR inhibition in vitro (% number of colonies of control[SD], NVP-BEZ235 vs NVP-BEZ235+HCQ: 45.0[17.9]% vs 24.0[8.4]%, P = .002) and in vivo (median survival of NVP-BEZ235- vs NVP-BEZ235+HCQ-treated mice: 38.5 days vs 47.0 days, P = .04).
CONCLUSION
Combined mTOR and autophagy inhibition may provide an attractive approach to target BCR-ABL-independent mechanism of resistance.
背景
伊马替尼和第二代酪氨酸激酶抑制剂（TKI）尼洛替尼和达沙替尼已显著延长慢性髓性白血病（CML）患者的预期寿命；然而，对 TKI 的耐药性仍然是一个主要的临床挑战。虽然第三代 TKI 帕纳替尼可改善包括 T315I 突变在内的 BCR-ABL 依赖性耐药机制的患者的疗效，但一部分患者可能会出现或发展出 BCR-ABL 非依赖性耐药性，并对帕纳替尼治疗产生耐药性。通过对帕纳替尼耐药性进行建模并检测来自这些 CML 患者的样本，希望能找到替代药物靶点，并使用新型化合物抑制该靶点。
方法
在帕纳替尼培养后，生成了两种获得性 BCR-ABL 非依赖性耐药的 CML 细胞系。使用 RNA 测序和基因本体论（GO）富集来检测帕纳替尼耐药细胞中异常的转录反应。使用经过验证的致癌基因药物库来鉴定对 TKI 耐药细胞有活性的美国食品和药物管理局（FDA）批准的药物。在 TKI 耐药患者（n=4）的骨髓（BM）衍生细胞和人异种移植小鼠模型（每组 n=4-6 只小鼠）中进行验证。所有统计检验均为双侧检验。
结果
我们表明，帕纳替尼耐药的 CML 细胞可通过 mTOR 的替代激活获得 BCR-ABL 非依赖性耐药。在转录组分析和药物筛选后，我们强调 mTOR 抑制是 TKI 耐药 CML 细胞的另一种治疗方法。此外，我们表明，催化 mTOR 抑制剂诱导自噬，并证明遗传或药理学抑制自噬可使帕纳替尼耐药的 CML 细胞对 mTOR 抑制诱导的细胞死亡敏感，在体外（对照[SD]的菌落数量百分比，NVP-BEZ235 与 NVP-BEZ235+HCQ：45.0[17.9]% 与 24.0[8.4]%，P=.002）和体内（NVP-BEZ235-与 NVP-BEZ235+HCQ 治疗小鼠的中位存活时间：38.5 天与 47.0 天，P=.04）。
结论
联合 mTOR 和自噬抑制可能为靶向 BCR-ABL 非依赖性耐药机制提供一种有吸引力的方法。
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