Near-IR Ratiometric Fluorescence Probes for Assessing Cargo Delivery to Prostate Tumors

项目摘要/摘要 前列腺特异性膜抗原(PSMA)是前列腺癌的标志性酶生物标志 因为它在几乎所有前列腺癌的上皮细胞中都有表达。除了这一独特的表达方式之外 前列腺癌，这导致了成像和治疗药物的靶向输送，内皮细胞 PSMA在前列腺癌和非前列腺癌新生血管中的表达 这是调节血管形成和改善药物输送的机会。 我们最近证明，在小分子PSMA靶向的基础上添加白蛋白结合基序 药物显著减缓清除，并允许肿瘤摄取近50%的注射剂量。我们的 磷酰胺靶向分子选择性地靶向PSMA的活性部位，并快速穿透前列腺 肿瘤细胞，内化为内小体/溶酶体。此外，我们的PHOS-AM链接器系统可以快速释放 货物在内体pH下稳定，但在生理pH下稳定。基于这些关键成果，我们目前 定位于开发第一个以PSMA为目标的有效SMDC。 然而，一个关键问题仍然是以PSMA为目标的成功开发和优化 药物结合物：肿瘤和非靶组织对PSMA靶向结合物的摄取是否直接相关 他们的货物被释放了？“我们的假设是，以PSMA为靶点的近红外比率荧光探针 (PSMA-NIR-RFP)可以报告PSMA阳性细胞和肿瘤的摄取和货物释放。 通道活体成像。我们将通过追求以下具体目标来检验我们的假设。活体内 该探针的性能将使用一种新的多细胞类型、3D生物打印的前列腺癌模型进行评估 准确代表PSMA(+)原发肿瘤血管系统，可用于异种移植小鼠模型。 目的#1：测定货物在体外的时空亚细胞蓄积和释放 PSMA(+)前列腺肿瘤细胞和肿瘤相关血管中的PSMA-NIR-RFP。这是我们的主张 PSMA-NIR-RFP可以报告内噬菌体和溶酶体中的摄取、运输和货物释放 PSMA(+)细胞，通过它们的pH触发的染料释放。 目标2：确定PSMA靶向结合物在靶和非靶向药物中的释放程度 PSMA(+)荷瘤小鼠模型靶组织的建立。我们的期望是肿瘤的量化- 可使用PSMA-NIR-RFP结合以下方法评估特定摄取和受控货物释放 双通道活体成像。 拟议工作的最重要成果是将开发PSMA-NIR-RFP并 用于模拟和报告PSMA靶向偶联物的体内吸收和货物释放，其 随后可应用于PSMA和其他生物标记物靶向药物结合物的优化。

PROJECT SUMMARY/ABSTRACT Prostate-specific membrane antigen (PSMA) is the hallmark enzyme-biomarker for prostate cancer because it is expressed in the epithelium of nearly all prostate cancers. In addition to this unique expression in prostate cancer, which has led to targeted delivery of imaging and therapeutic agents, the endothelial expression of PSMA on the neovasculature of both prostatic and non-prostatic tumors offers a broader opportunity to modulate the vascularization and improve drug delivery. We recently demonstrated that the addition of an albumin-binding motif to small-molecule PSMA-targeted agents dramatically slows clearance and allows for tumor uptake of nearly 50% of an injected dose. Our phosphoramidate targeting molecules selectively target the active-site of PSMA, and rapidly penetrate prostate tumor cells, internalizing to endosomes/lysosomes. In addition, our Phos-Am linker system can rapidly release cargo at endosomal pH but is stable at physiologically pH. Based on these key achievements, we are currently positioned to develop the first effective PSMA-targeted SMDC. However, a key question remains for the successful development and optimization of PSMA-targeted drug-conjugates, “is uptake of PSMA-targeted conjugates in tumor and non-target tissues directly correlated with their cargo release?” Our hypothesis is that a PSMA-targeted near-IR ratiometric fluorescence probe (PSMA-NIR-RFP) can report on both uptake and cargo-release in PSMA-positive cells and tumors using dual- channel in vivo imaging. We will test our hypothesis by pursuing the following specific aims. The in vivo performance of the probe will be evaluated using a novel multi-cell type, 3D bioprinted prostatic tumor model accurately represents PSMA(+) primary tumor vasculature and can be employed in xenograft mouse models. Aim #1: Determine the in vitro spatiotemporal subcellular accumulation and release of cargo from a PSMA-NIR-RFP in PSMA(+) prostate tumor cells and tumor-associated vasculature. It is our assertion that a PSMA-NIR-RFP can report on the uptake, trafficking, and cargo release in endosomes and lysosomes of PSMA(+) cells, through their pH-triggered dye release. Aim #2: Determine the extent of cargo-release from PSMA-targeted conjugates in target and non- target tissues in PSMA(+) tumor-xenograft mouse model. It is our expectation that quantification of tumor- specific uptake and controlled cargo-release can be assessed using a PSMA-NIR-RFP in combination with dual-channel in vivo imaging. The most important outcome of the proposed work is that a PSMA-NIR-RFP will be developed and employed to model and report on the in vivo uptake and cargo-release of PSMA-targeted conjugates, which can be subsequently applied to the optimization of PSMA and other biomarker-targeted drug-conjugates.