Fenretinide诱导的NF-κB抑制效应对急性髓系白血病化疗的增敏机制研究

In spite of much progress in acute myelogenous leukemia (AML) treatment,there are still some negative factors slowing AML therapy, including non-specific cytotoxicity and signaling pathways activation (for example,nuclear factor kappa B (NF-κB)) produced by current chemotherapeutic agents. Insensitive responses to current chemotherapeutic agents potentiate AML relapse and therapy failure, which provide a critical target for therapeutic intervention. Up to date, more efforts have been turned to discovering AML targeting agents, however,very few agents were reported to be capable of chemosensitizing AML chemotherapies and this slowed the progress in AML treatment. Through our pilot work, we found that fenretinide, a well-tolerated vitamin A derivative, was capable of selectively targeting AML leukemia stem cells by integrating NF-κB-inhibition, Wnt repression and ROS induction, while not affecting normal hematopoietic cells. The inner feature of NF-κB inhibition might confer chemoresistance reversal and/or chemosensitizing capability to fenretinide. Based on these findings, we proceeded our study and found low dose of fenretinide could not efficiently kill AML cells but increase the efficacy of current chemotherapeutic agents (cytosine arabinoside (Ara-C) and idarubicin) on AML cells. In this study, we will perform a series of cell biology, molecular biology and xenograft experiments to identify the mechanisms of NF-κB inhibition induced by fenretinide and the efficacy of fenretinide in chemosensitizing AML cells and/or AML initiating cells to current chemotherapeutic agents,and explore combinational chemotherapy regimens to reduce the application dosage and side effects of current chemotherapeutic agents. Moreover, by performing single cell network profiling (SCNP), apoptotic-pathway screening and microarray assays, we will detail its AML therapy chemosensitizing mechanism. By introducing chemosensitizing agents into AML treatment, we can avoid increasing chemotherapy dosage blindly, reduce the application dosage and treatment-related mortality, and improve the treatment compliance. This study will not only provide new insights into leukemia treatment, but also deepen our understanding of the pathogenesis and treatment strategies of leukemia and boost the translation from bench to bedside.

虽然化疗在急性髓系白血病(AML)治疗方面取得了一定的效果，然而其在杀伤癌细胞的同时不仅损害了正常细胞，还会通过激活核因子kappa B（NF-κB）等造成化疗低敏及继发性耐药,严重影响AML治疗。因此亟待开发能增敏化疗/逆转耐药而对正常细胞无影响的药物。我们的前期研究发现Fenretinide 这一低毒性的维甲酸衍生物能通过抑制NF-κB、Wnt等信号通路和激活ROS特异性地杀伤白血病干细胞。Fenretinide 对NF-κB信号通路的抑制特性提示其对白血病细胞还可能具有增敏化疗/逆转耐药的潜能。本项目在预实验中初步发现该现象的存在。为此，本项目将采用一系列分子生物学实验、动物实验、SCNP和生物信息分析明确fenretinide产生NF-κB抑制的机制以及其在化疗增敏/逆转耐药中的作用和分子机制。本研究不仅为优化白血病的治疗提供新思路，也为全面认识白血病的发生发展提供理论基础。

虽然化疗在急性髓系白血病(AML)治疗方面取得了一定的效果，然而其在杀伤癌细胞的同 时不仅损害了正常细胞，还会通过激活核因子kappa B（NF-κB）等造成化疗低敏及继发 性耐药,严重影响AML治疗。因此亟待开发能增敏化疗/逆转耐药而对正常细胞无影响的药 物。本项目通过荧光素酶报告基因反应、药物毒性反应实验、荧光定量PCR、蛋白印迹和流式细胞等实验方法发现：Fenretinide能抑制AML化疗药物引起的NF-kappaB活化，同时联合低剂量常规化疗药物使用的情况下，能达到中高剂量常规化疗药物的细胞杀伤作用，调控NF-kappaB靶基因的表达。除了在细胞系实验得到该结果外，我们还在临床AML样本中同样获得类似结果，并发现Fenretinide在作用于AML细胞的时候，能够降低多药耐药蛋白的表达。Fenretnide这一低毒性、无致畸性/致癌性的化合物，在低剂量使用的时候，能够抑制NF-kappaB活性，能联合低剂量化疗药物达到化疗增敏和避免耐药的发生，高剂量使用时候能靶向清除AML白血病干细胞。这些结果都提示Fenretinide的药效双重性在AML的临床中具有良好的转化潜质。