Mechanism of Therapy in high-risk AML

急性髓系白血病(AML)是一种侵袭性的血液系统恶性肿瘤，尽管可以用良好的药物治疗- 明确的化疗方案，在归类为高危AML的所有病例中，有一半以上最终是致命的。 MLL、Flt3、DNMT3A和P53基因突变与高危AML相关。甚至靶向的Flt3抗激酶 治疗占AML的30%，但未能在这一组AML中产生持久的反应。合作社 致癌信号“被认为是治疗效果差的原因，但缺乏机制上的了解。基座 在我们最近的出版物和新的初步数据中，我们发现协同致癌信号收敛 C-fos和DUSP1导致癌细胞凋亡阈值升高并提供药物 抵抗。因此，c-fos和DUSP1的遗传或药物抑制使癌细胞对 化疗(Kesarwani等艾尔自然医学2017年)。C-fos和DUSP1的表达增强 在高危AML患者中，但在低危AML患者中不是。C-fos和c-fos的遗传和化学抑制 在一个模型中，DUSP1导致TKI和传统化疗药物的药物敏感性增加 高危AML(FLT3ITD+MLLAF9)。因此，我们假设急性髓系白血病中的协同致癌信号 诱导c-fos和DUSP1的表达，导致耐药和疾病复发 细胞凋亡阈值。在目标1中，我们将确定c-fos和DUSP1对于 由FLT3ITD+DNMT3Amut+NPM1C驱动的最常见、最具侵袭性和致命性AML的转化 Flt3ITD+P53突变。我们将研究c-fos和DUSP1依赖的细胞基础。 C-基因缺失和药物抑制对AML小鼠模型和原发患者样本的风险 FOS和DUSP1。接下来，我们建议进行实验，以了解合作的机制基础。 通过c-fos和DUSP1的致癌信号导致AML的转化和治疗失败，其中 新的治疗策略的目标。根据我们的初步数据，我们假设c-fos和DUSP1 信号汇聚到特定AP-1转录介导的癌基因激活的增强子上 复合体。在c-fos和DUSP1存在下，AP-1复合体由c-fos-jun组成，介导 在没有c-fos和DUSP1的情况下，Jun家族同源二聚体(Jun- JunB，JunB-Jund，Jun-Jund)占主导地位，无法支持白血病细胞状态。在目标2中， 我们将把c-fos-jun AP-1和DUSP1活性与全球增强子染色质动力学联系起来。 此外，我们将利用染色质嵌入的目标基因报告基因来提供详细的分析 高危AML中单细胞水平的功能相关下游基因。拟议的工作是可望完成的 阐明c-fos和DUSP1信号在高危AML中的必要性，并提供深入的 白血病转化和耐药机制的分子洞察。我们期待着 这些信息不仅对急性髓细胞白血病，而且对治疗耐药肿瘤的广泛群体都是有用的。

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy that, despite being treatable with well- defined chemotherapy regimens, is ultimately fatal in over half of all cases categorized as high-risk AML. Mutations in MLL, FLT3, DNMT3A and P53 are associated with high-risk AML. Even targeted FLT3 anti kinase therapy, which constitutes 30 % of AML, failed to engender durable response in this group of AML. Co-operative oncogenic signaling” was attributed to poor therapeutic outcome, but lacks mechanistic understanding. Based on our recent publication and new preliminary data, we found that co-operative oncogenic signaling converges on c-FOS and DUSP1, which results in an increased apoptotic threshold in cancer cells and confers drug resistance. Thus, genetic or pharmacologic inhibition of c-FOS and DUSP1 sensitizes cancer cells to chemotherapy (Kesarwani, et. al. Nature Medicine 2017). We show greater expression of c-FOS and DUSP1 in high-risk AML patients, but not in low risk-AML patients. Both genetic and chemical inhibition of c-FOS and DUSP1 results in increased drug sensitivity to both TKI and conventional chemotherapeutic drugs in a model of high-risk AML (FLT3ITD+MLLAF9). Thus, we hypothesize that co-operative oncogenic signaling in AML induces the expression of c-FOS and DUSP1 resulting to drug resistance and disease relapse due to elevated apoptotic threshold. In Aim 1, we will determine whether c-FOS and DUSP1 are necessary and sufficient for transformation in a most frequent, aggressive, and fatal AML driven by FLT3ITD+DNMT3Amut+NPM1C and FLT3ITD+P53mut mutations. We will examine the cellular basis of c-FOS and DUSP1 dependency in the high- risk AML mouse models and primary patient samples by genetic deletion and pharmacological inhibition of c- FOS and DUSP1. Next, we propose experiments to understand the mechanistic basis for how co-operative oncogenic signaling via c-FOS and DUSP1 contributes to transformation and treatment failure in AML, with the goal for novel treatment strategies. Based on our preliminary data, we hypothesize that c-FOS and DUSP1 signaling converges upon oncogenically-activated enhancers mediated by specific AP-1 transcriptional complexes. In the presence of c-FOS and DUSP1, AP-1 complexes consist of c-FOS-JUN, which mediate oncogenically-active enhancers, while in the absence of c-FOS and DUSP1, Jun family homodimers (JUN- JUNB, JUNB-JUND, JUN-JUND) predominate which are unable to support the leukemic cell state. In Aim 2, we will molecularly link c-FOS-JUN AP-1 and DUSP1 activity to global enhancer chromatin dynamics. Moreover, we will exploit chromatin-embedded target-gene-reporter alleles to provide a detailed analysis of functionally-relevant downstream genes at a single-cell level in high-risk AML. The proposed work is expected to delineate the necessity of c-FOS and DUSP1 signaling in high-risk AML, as well as to provide deep molecular insight into the mechanisms underlying leukemic transformation and drug resistance. We expect that this information will be informative not only for AML, but also the broad group of treatment resistant tumors.