Mitochondrial Apoptotic Sensitivity in Predicting Acute Myeloid Leukemia Response

成人急性髓系白血病是一种初治成功率非常高的癌症，但许多患者由于复发而长期失败。一种解释是，耐药亚群可能在最初的治疗中存活下来，以重建癌症。已经观察到，对化疗的抵抗与细胞凋亡的敏感性有关，这种敏感性由线粒体上bcl2家族成员之间的相互作用决定。特别是，我们发现在细胞系中，线粒体对凋亡信号的敏感性降低，其形式类似于BH3(BH3)结构域，与细胞对化疗的敏感性降低有关。为了测量复杂、异质的原发AML样本中单个细胞的线粒体敏感性，我们开发了一种基于这些肽反应的基于FACS的BH3图谱技术。这项建议旨在测试BH3图谱是否可以作为患者预后的预测指标，检测耐药亚群，并识别可能的bcl2家族抗凋亡成员，这些成员可以选择性地杀伤AML细胞，但不能选择性地杀死重要的正常造血祖细胞。此外，由于BH3多肽通过抑制某些抗凋亡的bcl2家族成员而特异性地杀伤，因此某些多肽的杀伤效果可以表明哪些bcl2成员将成为未来药物靶向的良好候选者。

Adult acute myeloid leukemia is a type of cancer that exhibits a remarkably high initial treatment success rate yet many patients fail long-term due to relapse. One explanation is that a drug resistant subset may survive initial treatment to re-establish the cancer. It has been observed that resistance to chemotherapy correlates with apoptotic sensitivity determined by the interactions among the BCL-2 family members at the mitochondrion. Particularly, we have found in cell lines that diminished mitochondrial sensitivity to apoptotic signals in the form of peptides mimicking the Bcl-2 homology 3 (BH3) domains correlates with decreased cellular sensitivity to chemotherapy. To measure the mitochondrial sensitivity of individual cells in complex, heterogeneous primary AML samples, we have developed a FACS-based BH3 profiling technique based on these peptide responses. This proposal aims to test if BH3 profiling can serve as a prognostic predictor of patient outcome, detect resistant subsets and identify possible BCL-2 family anti-apoptotic members that can be targeted to selectively kill AML cells but not important normal hematopoietic progenitors. Furthermore, since the BH3 peptides specifically kill by inhibiting certain anti-apoptotic BCL-2 family members, the effectiveness of killing by certain peptides can show which BCL-2 members would be good candidates for future drug targeting.