Epigenetic Regulation of Drug Resistance to ABT-199 in B-cell Malignancies

虽然人们已经付出了巨大的努力来了解获得性耐药的分子事件，但并不多。 人们已经注意到治疗过程中发生的事情，特别是在早期阶段， 对药物治疗仍有反应维奈托克（ABT-199），一种新的有效和选择性的小分子BCL-2 抑制剂，最近已成为包括MCL在内的造血肿瘤的有效疗法。而 对ABT-199的反应通常是戏剧性的，它们很少是持久的，并且非常需要 改善反应的持续时间并延迟或防止耐药性（DR）。我们将耐药性建模为 ABT-199抗性细胞系，并表征了适应性分子 在MCL系和原代样品中重编程为ABT-199处理。更复杂、更动态 比我们预期的，我们一直检测到一个淋巴瘤细胞的小亚群，逃避强 选择性ABT-199压力通过进入可逆的药物耐受“坚持”状态（DTP），导致DTP 扩大人口（DTEP）和最终获得真正的耐药性。我们观察到， DTEP细胞被赋予增加的存活、克隆形成生长并与BH 3家族蛋白相关 重新编程有趣的是，DTEP细胞在长期传代后恢复到药物敏感状态，而没有 药物，支持这些细胞表观遗传重编程到耐药状态。符合 通过使用药物筛选方法，我们观察到表观遗传调节因子如BRD 4， PRMT 5、CDK 9和EP 300是药物耐受性和耐药性演变所必需的，并有助于药物耐受性和耐药性演变。 最近，针对H3 K27的RNA测序（RNA-seq）和ChIP-seq发现了超级增强子（SE） 在DTEP细胞中重塑，支持表观遗传调节的SE重塑是DTEP细胞中所需的。 转录重编程和耐药性进化。我们的中心假设是，转录和 表观遗传适应性反应和对ABT-199治疗的协调赋予MCL药物耐受性 和治疗的脆弱性，以防止随后的耐药性演变的MCL。的目的 建议是战略性地靶向表观遗传转录机制，并提供临床前验证 表观遗传学靶向与BCL-2拮抗剂的组合作为针对MCL的治疗方法。的 这项研究使我们能够深入了解MCL耐药生物学，并揭示一种新的机制- 治疗MCL患者。

While enormous effort has gone into understanding the molecular events in acquired resistance, not much attention has been given to what happens during treatment, particularly during the early phase when patients still respond to drug treatment. Venetoclax (ABT-199), a novel potent and selective small-molecule BCL-2 inhibitor, has recently emerged as an effective therapy for hematopoietic tumors including MCL. While responses to ABT-199 can often be dramatic, they are rarely durable, and there is a significant need to improve the duration of response and delay or prevent drug resistance (DR). We modeled drug resistance to ABT-199 by generating ABT-199 resistant cell lines from MCL, and characterized the adaptive molecular reprogramming to ABT-199 treatment in MCL lines and primary samples. More complex and more dynamic than we had anticipated, we consistently detected a small subpopulations of lymphoma cells that evade strong selective ABT-199 pressure by entering a reversible drug tolerant 'persister' state (DTP), leading to DTP expansion population (DTEP) and eventual acquisition of bona fide drug resistance. We observed that these DTEP cells are conferred increased survival, clonogenic growth and are associated with BH3 family protein reprogramming. Intriguingly, DTEP cells revert back to drug sensitive states after long term passage without the drug, supporting that these cells are epigenetically reprogrammed to drug resistant states. Consistent with these results, by using drug screen approaches, we observed that epigenetic regulators such as BRD4, PRMT5, CDK9 and EP300 are required for and contribute to drug tolerance and drug resistance evolution. Most recently, RNA sequencing (RNA-seq) and ChIP-seq against H3K27Acrevealed super-enhancers (SE) remodeling in DTEP cells, supporting that epigenetically regulated SEs remodeling is required for transcriptional reprogramming and drug resistance evolution. Our central hypothesis is that transcriptional and epigenetic adaptive response and coordination in response to ABT-199 treatment confer MCL drug tolerance and therapeutic vulnerability to prevent subsequent drug resistance evolution in MCL. The objective of this proposal is to strategically target epigenetic transcription machinery and provide pre-clinical validation of combination of epigenetically targeting with BCL-2 antagonist as a therapeutic approach against MCL. The study allows us to gain valuable insights into MCL drug resistance biology and uncover a novel mechanism- driven therapy for MCL patients.