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

项目总结/摘要 前列腺特异性膜抗原（PSMA）是前列腺癌的标志性酶-生物标志物 因为它在几乎所有前列腺癌的上皮中表达。除了这种独特的表达方式， 前列腺癌，这导致了成像和治疗剂的靶向递送，内皮细胞 PSMA在前列腺和非前列腺肿瘤的新生血管中的表达提供了更广泛的 调节血管形成和改善药物递送的机会。 我们最近证明，在小分子PSMA靶向的细胞中加入白蛋白结合基序， 药物显著减缓清除，并允许肿瘤摄取近50%的注射剂量。我们 氨基磷酸酯靶向分子选择性地靶向PSMA的活性位点，并快速渗透前列腺 肿瘤细胞，内化至内体/溶酶体。此外，我们的Phos-Am连接器系统可以快速释放 货物在内体pH下，但在生理pH下稳定。基于这些关键成就，我们目前正在 定位于开发第一个有效的PSMA靶向SMDC。 然而，一个关键问题仍然是成功的发展和优化的PSMA为目标的 药物缀合物“是肿瘤和非靶组织中PSMA靶向缀合物的摄取直接相关 他们的货物释放“我们的假设是，PSMA靶向的近红外比率荧光探针 （PSMA-NIR-RFP）可以使用双通道技术报告PSMA阳性细胞和肿瘤中的摄取和货物释放。 通道体内成像。我们将通过追求以下具体目标来检验我们的假设。体内 将使用新型多细胞类型、3D生物打印前列腺肿瘤模型来评估探针的性能 准确地代表PSMA（+）原发性肿瘤血管系统，并且可以用于异种移植小鼠模型。 目的#1：确定从细胞中释放的货物的体外时空亚细胞积累和释放。 a PSMA（+）前列腺肿瘤细胞和肿瘤相关脉管系统中的PSMA-NIR-RFP。我们认为 PSMA-NIR-RFP可以报告内体和溶酶体中的摄取，运输和货物释放 PSMA（+）细胞，通过其pH触发的染料释放。 目的#2：确定靶向和非靶向PSMA靶向缀合物的货物释放程度。 PSMA（+）肿瘤异种移植小鼠模型中的靶组织。我们期望肿瘤的定量- 可以使用PSMA-NIR-RFP结合以下方法评估特定摄取和受控货物释放： 双通道体内成像。 拟议工作的最重要成果是将制定一份PSMA-NIR-RFP， 用于模拟和报告PSMA靶向缀合物的体内摄取和货物释放， 可以随后应用于PSMA和其他生物标志物靶向药物缀合物的优化。

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.