肽修饰MRI纳米造影剂启动UPP和ALP双通路降解AR靶向诊疗前列腺癌的研究

雄激素-雄激素受体（AR）信号通路对前列腺癌（PCa）发生、进展及治疗极为关键。然而，临床上通过全源阻断雄激素合成或拮抗雄激素与AR结合对去势抵抗性前列腺癌（CRPC）的疗效有限，因此降解AR成为治疗CRPC的新思路，但尚无靶向降解AR的药物。申请人论文报道MRI纳米造影剂MnFe2O4可通过泛素-蛋白酶体通路（UPP）降解AR结构蛋白PolyQ，预实验结果显示MnFe2O4可通过UPP降解AR并抑制PCa增殖。本项目拟将PCa靶向肽、穿膜自噬增强肽及AR结合肽偶联至MnFe2O4，增强MRI诊断效能，进一步通过上调自噬水平并捕获AR使其进入自噬-溶酶体通路（ALP）降解，实现UPP和ALP双通路降解AR治疗CRPC。在体内外运用IF/IHC及Co-IP联合MS、WB等实验手段，鉴定并发掘AR泛素化修饰、连接、蛋白酶体识别等过程中的关键分子，阐释双通路降解机制，为PCa靶向诊疗提供新策略。

Androgen-androgen receptor (AR) signaling pathway plays an extremely vital role in prostate cancer (PCa) initiation, progression and therapy. However, in clinical practice, neither complete androgen blockade nor AR antagonists could achieve effective therapeutic efficacy for castration-resistant prostate cancer (CRPC). Alternatively, managing to degrade AR possesses great potential in CRPC therapy. Whereas, there are no any drugs could target AR for efficient degradation. Most recently, we have reported that T2-modal magnetic resonance imaging (MRI) contrast agent MnFe2O4 nanoparticles could accelerate the degradation of polyglutamine (Poly Q, protein aggregation constitutes part of the N-terminus domain of AR) through ubiquitin-proteasomal pathway (UPP). Based on these findings, we have further demonstrated that MnFe2O4 nanoparticles degraded AR via UPP and subsequently inhibited PCa proliferation. Thus, in the current proposal, we intend to conjugate MnFe2O4 nanoparticles with prostate-specific membrane antigen-targeting peptide (PSMATP), cell-permeable and autophagy-enhancing peptide (TAT-Beclin-1) and androgen receptor binding peptide (ARBP) to obtain MnFe2O4-PSMATP-TAT-Beclin-1-ARBP. The peptides-conjugated nanoparticles may remarkably enhance the T2-MRI contrast for PCa diagnosis and also upregulate autophagy-inducing ability for capturing AR to enter autophagy-lysosomal pathway (ALP) for degradation and eventually prevent CRPC progression coordinatively through UPP and ALP. Moreover, to lend in vitro and in vivo experiments by using the immunofluorescence (IF)/immunohistochemistry (IHC) and co-immunoprecipitation (Co-IP) combined with mass spectrometry (MS) and western-blotting (WB), we expect to screen and identify the crucial molecular components or receptors and elucidate the mechanisms underlying the modulatory action in the processes of ubiquitination, ligation, substrate recognition by the proteasome and UPP-ALP dual modal degradation of AR, which efforts could shed light on valuable strategies and feasible approaches for targeted theragnosis of PCa.