Proteolytic activity in the tumor microenvironment is one of the key elements supporting tumor development and metastasis. One of the key families of proteases that are overexpressed in various types of cancer and implicated in different stages of tumor progression are cysteine cathepsins. Among them, cathepsins S and L can be secreted into the tumor microenvironment by tumor and/or immune cells, making them promising drug delivery targets. Here we present a new system for cathepsin S/L targeting using a liposomal drug carrier system functionalized with the endogenous cysteine cathepsin inhibitor, stefin A. The selective targeting of cathepsins by stefin A-conjugated liposomes was confirmed in vitro and in vivo, demonstrating the potential of this approach for cancer diagnosis and treatment.

中文翻译：

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Stefin A功能化脂质体作为组织蛋白酶S和L靶向药物递送的系统。

肿瘤微环境中的蛋白水解活性是支持肿瘤发展和转移的关键因素之一。半胱氨酸组织蛋白酶是在各种类型的癌症中过表达并涉及肿瘤进展的不同阶段的蛋白酶的关键家族之一。其中，组织蛋白酶S和L可以被肿瘤和/或免疫细胞分泌到肿瘤微环境中，使其成为有希望的药物递送靶标。在这里，我们介绍了一种新的针对组织蛋白酶S / L靶向的系统，该系统使用的脂质体药物载体系统具有内源性半胱氨酸组织蛋白酶抑制剂stefin A功能。在体外和体内均证实了通过与stefin A偶联的脂质体对组织蛋白酶的选择性靶向。这种方法在癌症诊断和治疗中的潜力。