Intracellular Self-Assembly of Theranostic Nanoparticles for Enhanced Imaging and Tumor Therapy

我们的总体目标是开发一种基于精度的纳米温差成像平台，其中成像信号可以 作为纳米粒子在细胞内蓄积和治疗的早期预测成像生物标志物 回应。新的抗癌药物在继续开发，但许多药物由于肿瘤的发展而失败。 抗药性。作为药物外排泵的细胞膜蛋白已经被确定，而当 一些有希望的药物进入肿瘤细胞，它们不能总是保留足够长的时间来发挥作用。我们的目标是 开发在前列腺癌细胞中过表达的豆蛋白(一种天冬酰胺内肽酶) 对于奥沙拉嗪(Olsa)-偶联肽底物的特定切割，随后底物自身 组装成细胞内的纳米颗粒。这种酶驱动的自组装有几个目的：1) 以最小的药物外排进行细胞内包埋；2)延长肿瘤药物的暴露时间；以及3)对 正常器官由于未组装的单分子在血液中迅速清除。我们有初步数据 证明这一概念在体内是可行的。因为它不仅作为一种抗癌药物 抑制DNA甲基化，也可作为非金属、无标记的化学交换造影剂 在饱和转移磁共振成像(CEST MRI)中，奥沙拉秦是一种独特的治疗药物。这个 药物可以在没有修饰的情况下可视化，允许直接成像，而不需要药物改变 可能影响自组装和/或生物分布。在体外筛选出最佳的Olsa-CBT-800CW-Rn- 在豆蛋白高表达DU145细胞中具有最大肿瘤细胞穿透性和存留率的AAN底物 (目标1)，我们将在原位小鼠前列腺中测试该化合物的体内纳米消融特性。 肿瘤模型(AIM 2)和转基因小鼠模型(TRAMP小鼠)，在该模型中，正常前列腺细胞经历 随着时间的推移恶性转化(目标3)。如果成功，这种方法可能会扩展到其他酶- 靶向CEST MRI-可检测的治疗平台，用于成像肿瘤侵袭性、药物积累 并预测治疗反应。

Our overall aim is to develop a precision-based nanotheranostic platform where the imaging signal may serve as an early predictive imaging biomarker for intracellular nanoparticle accumulation and therapeutic response. New anti-cancer agents continue to be developed, but many fail due to the tumor developing (multi-) drug resistance. Cellular membrane proteins acting as a drug efflux pump have been identified, and while some promising agents enter tumor cells, they cannot always be retained long enough to be effective. We aim to exploit the enzyme legumain (an asparaginyl endopeptidase) that is overexpressed in prostate cancer cells for specific cleavage of an olsalazine (Olsa)-conjugated peptide substrate, following which the substrate self- assembles into intracellular nanoparticles. This enzyme-driven self-assembly serves several purposes: 1) intracellular entrapment with minimal drug efflux; 2) prolonged tumor drug exposure; and 3) minimal toxicity to normal organs due to rapid blood clearance of non-assembled single molecules. We have preliminary data demonstrating this concept to be feasible in vivo. Since it does not only serve as an anti-cancer drug through inhibition of DNA methylation, but also as a non-metallic, label-free contrast agent for chemical exchange saturation transfer magnetic resonance imaging (CEST MRI), olsalazine is a unique theranostic agent. The drug can be visualized without modification, allowing direct imaging without pharmacological alterations that may affect self-assembly and/or biodistribution. Following in vitro selection of an optimal Olsa-CBT-800CW-Rn- AAN substrate with maximum tumor cell penetration and retention in legumain-overexpressing DU145 cells (Aim 1), we will test this compound for its in vivo nanotheranostic properties in an orthotopic mouse prostate tumor model (Aim 2) and a transgenic mouse model (TRAMP mouse) where normal prostate cells undergo a malignant transformation over time (Aim 3). If successful, this approach may be extended to other enzyme- targeted CEST MRI-detectable theranostic platforms for imaging tumor aggressiveness, drug accumulation, and predicting therapeutic response.