蛋白类泛素化修饰调控前列腺癌发生和进展及其AR与非AR信号通路依赖机制研究

The incidence of prostate cancer (PCa) has been rapidly growing in China over the last decade. Inevitable progression to castration resistant prostate cancer (CRPC) following androgen deprivation therapy (ADT) has been observed, posing a significant threat to male’s health in our country. Androgen receptor (AR) signaling pathway and prostate cancer stem cell (PrCSC) lacking AR expression have been implicated in the occurrence of PCa and progression to CRPC. We previously found that a selective neddylation inhibitor, Pevonedistat, significantly repressed the expression of AR and AR-V7 - an AR splice variant reported to be highly associated with the progression to CRPC. A Skp2 inhibitor was recently reported to suppress PrCSC traits by deactivating Skp1-Cul1-Skp2 complex which could also be deactivated by Pevonedistat through inhibition of Cul1 neddylation. Therefore, we hypothesize that Pevonedistat has potential therapeutic value for PCa by suppressing AR signaling pathway and PrCSC traits. To prove our hypothesis, multidisciplinary techniques and methods will be used to identify the key molecule(s) and elucidate the underlying mechanisms of how AR signaling pathway and PrCSC traits are regulated by neddylation. This project will provide a new insight and may offer new target(s) to the development of therapeutic compounds for prostate cancer.

前列腺癌（PCa）近年来在我国的发病率快速增长，而接受雄激素去势治疗的患者终将耐药，这已严重影响到我国男性的健康。PCa的发生和进展为去势抵抗前列腺癌，与雄激素受体（AR）信号通路和不表达AR的前列腺肿瘤干细胞密切相关。我们前期发现：类泛素化修饰抑制剂Pevonedistat显著抑制AR和去势抵抗前列腺癌高度相关性AR变构体AR-V7的表达；据报道，Skp2抑制剂通过抑制Skp1-Cul1-Skp2复合体活性可抑制前列腺肿瘤干细胞特性，而Pevonedistat通过抑制Cul1蛋白类泛素化同样可抑制该复合体活性。因此我们推测，Pevonedistat可能通过抑制AR信号通路和前列腺肿瘤干细胞特性对前列腺癌具有治疗作用。在本申请项目中，我们拟采用多学科实验技术与方法，探索类泛素化修饰对AR信号通路和前列腺肿瘤干细胞特性的调控作用机制与关键分子，为PCa的药物治疗提供新的研究思路和治疗靶点。

雄激素受体（AR）及其组成性激活变体（AR-Vs）与前列腺癌的进展和复发有广泛的联系，使其成为治疗前列腺癌的有吸引力的靶点。类泛素化修饰是否调控雄激素受体，其调控方式和该潜在调控的治疗意义，是目前相对未被探索的研究领域。本文报告表明，因药物抑制剂MLN4924或ShRNA慢病毒载体诱发的类泛素化激活酶（NAE）基因敲除使得类泛素化失活，从而有选择地抑制了前列腺癌细胞的生长和存活，而对正常前列腺上皮细胞的影响较小。MLN4924还显著抑制了前列腺癌细胞的侵袭能力。此外，与单药治疗相比，MLN4924联合雄激素受体拮抗剂或去势治疗在体外显著增强了对前列腺癌细胞的生长抑制，并在体内异种移植模型中促进了肿瘤生长。原理上，MLN4924抑制了AR或AR-V7及其下游靶点的转录，并阻断了MMP2和MMP9的表达。综上所述，我们的研究表明，类泛素化修饰通路对AR或AR-V7转录具有正向调控作用，而类泛素化修饰抑制剂MLN4924具有治疗侵袭性前列腺癌的潜力。