APE1 蛋白/miR-221/222耦合介导肺癌凋亡抵抗及其分子机制

Apoptosis-resistance is one of the most common mechanisms of cancer therapy resistance. OncomiR is a subset of microRNAs plays important roles in apoptosis-resistance. However, the processing and maturation mechanisms of oncomiR are different from the majority of miRNAs with the detailed mechanisms yet to be elucidated. We have discovered that a key DNA repair protein APE1 can bind to an oncomiR, the primary miR-221/222 in cancer cells. When knocking down APE1, the level of pri-miR-221/222 elevated while mature miR-221/222 reduced. Based on this discovery and the RNase activity of APE1, we hypothesized that the functional meaning of the bound of APE1 protein and pri-miR-221/222 would be in the regulation of processing of miR-221/222 by the RNase activity of APE1. The current project will reveal the mechanisms of miR-221/222 maturational regulation by APE1 and its roles in the apoptosis-resistance of lung cancer by taking advantage of biochemical assays, in vitro cell models and in vivo APE1 conditional knockout mouse model. Moreover, very likely, this project, by studying the involvement of APE1 in miR-221/222 maturation, is helpful to understand the novel rules of oncomiR processing, shedding light on the future lung cancer therapeutics by targeting apoptosis.

凋亡抵抗是肿瘤治疗抵抗的普遍机制，癌性miRNA（oncomiR）在肿瘤中可促进凋亡抵抗，其成熟机制与多数miRNA存在差异，但分子机制尚不完全清楚。新近报道APE1具有RNA酶活性，但其生物学意义不明。我们前期发现DNA修复蛋白APE1可与一种oncomiR—miR-221/222前体直接结合；在肺癌细胞中敲低APE1可导致成熟miR-221/222下降。据此，我们推测APE1蛋白与miR-221/222前体耦合，可能通过其RNA酶活性促进miR-221/222的剪切成熟。本研究拟通过生化和细胞实验，以及APE1条件敲除小鼠模型，揭示APE1调控miR-221/222剪切成熟的分子机制及其在肺癌凋亡抵抗的重要作用。本研究以APE1参与miR-221/222成熟机制为切入点，有助于阐明APE1参与oncomiR剪切成熟的普遍规律，为克服肺癌的治疗抵抗提供科学依据。

哺乳动物脱嘌呤/脱嘧啶核酸内切酶APE1是一种DNA修复酶，参与基因组稳定性和基因表达，参与氧化应激反应，肿瘤进展和化疗耐药。然而，APE1在这些过程中作用的分子机制仍不清楚。最近的研究发现了APE1在RNA代谢中的新作用。通过对APE1与RNA和其他蛋白相互作用组的研究，我们证明APE1在遗传毒性刺激下能与DROHA复合物耦合，在pri-miRNA的加工和稳定性中发挥作用。我们还发现，APE1的redox活性是miR-221/222在调节肿瘤抑制因子PTEN表达过程中所必需的。对不同癌症的队列分析证实了我们的发现与肿瘤生物学的相关性。我们还发现，APE1参与了肿瘤进化过程中RNA相互作用组和蛋白质相互作用组，从而证实了其对癌症基因的转录后作用，同时我们也发现APE1在细胞对氧化应激的反应中发挥重要作用，并与肿瘤突变、肿瘤进展和化疗耐药有关。项目资助发表SCI论文1篇，待发表2篇。培养博士研究生2名，硕士研究生1名，其中2名已经取得博士学位，1名在读。项目投入经费58万元，支出45.25万元，各项支出基本与预算相符，剩余经费12.75万元，剩余经费计划用于本项目研究后续支出。

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