Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery System, School of Pharmaceutical Sciences, Peking University , Beijing 100191, P. R. China.
School of Pharmacy, Jilin Medical University , Jilin City 132013, P. R. China.
ACS Appl Mater Interfaces. 2017 Mar 29;9(12):10519-10529. doi: 10.1021/acsami.7b01056. Epub 2017 Mar 14.
Cell-penetrating peptide (CPP), also called "Trojan Horse" peptide, has become a successful approach to deliver various payloads into cells for achieving the intracellular access. However, the "Trojan Horse" peptide is too wild, not just to "Troy", but rather widely distributed in the body. Thus, there is an urgent need to tame the wildness of "Trojan Horse" peptide for targeted delivery of antineoplastic agents to the tumor site. To achieve this goal, we exploit a masked CPP-doxorubicin conjugate platform for targeted delivery of chemotherapeutic drugs using charge-guided masking and protease-triggered demasking strategies. In this platform, the cell-penetrating function of the positively CPP (d-form nonaarginine) is abrogated by a negatively shielding peptide (masked CPP), and between them is a cleavable substrate peptide by the protease (MMP-2/9). Protease-triggered demasking would occur when the masked CPP reached the MMP-2/9-riched tumor. The CPP-doxorubicin conjugate (CPP-Dox) and the masked CPP-Dox conjugate (mCPP-Dox) were used as models for the evaluation of masking and demasking processes. It was found that exogenous MMP-2/9 could effectively trigger the reversion of CPP-cargo in this conjugate, and this trigger adhered to the Michaelis-Menten kinetics profile. This conjugate was sensitive to the trigger of endogenous MMP-2/9 and could induce enhanced cytotoxicity toward MMP-2/9-rich tumor cells. In vivo antitumor efficacy revealed that this masked conjugate had considerable antitumor activity and could inhibit the tumor growth at a higher level relative to CPP-cargo. Low toxicity in vivo showed the noticeably decreased wildness of this conjugate toward normal tissues and more controllable entry of antitumor agents into "Troy". On the basis of analyses in vitro and in vivo, this mCPP-cargo conjugate delivery system held an improved selectivity toward MMP-2/9-rich tumors and would be a promising strategy for tumor-targeted treatment.
细胞穿透肽（CPP），也称为“特洛伊木马”肽，已成为将各种有效载荷递送到细胞内以实现细胞内进入的成功方法。然而，“特洛伊木马”肽太狂野，不仅“攻击”特洛伊，而且广泛分布在体内。因此，迫切需要驯服“特洛伊木马”肽的野性，以将抗肿瘤剂靶向递送到肿瘤部位。为了实现这一目标，我们利用一种被掩蔽的 CPP-阿霉素缀合物平台，通过电荷引导掩蔽和蛋白酶触发去掩蔽策略来靶向递送化疗药物。在这个平台中，通过带负电荷的屏蔽肽（被掩蔽的 CPP）来削弱正 CPP（D 形九聚精氨酸）的细胞穿透功能，在它们之间是一种可被蛋白酶（MMP-2/9）切割的底物肽。当被掩蔽的 CPP 到达富含 MMP-2/9 的肿瘤时，会发生蛋白酶触发的去掩蔽。CPP-阿霉素缀合物（CPP-Dox）和被掩蔽的 CPP-Dox 缀合物（mCPP-Dox）被用作掩蔽和去掩蔽过程评估的模型。结果发现，外源性 MMP-2/9 可以有效地触发该缀合物中 CPP-有效载荷的反转，并且这种触发符合米氏-门坦动力学特征。该缀合物对内源性 MMP-2/9 的触发敏感，并能诱导对富含 MMP-2/9 的肿瘤细胞产生增强的细胞毒性。体内抗肿瘤功效表明，这种被掩蔽的缀合物具有相当的抗肿瘤活性，并且可以在更高水平上抑制肿瘤生长，相对于 CPP-有效载荷。体内低毒性表明，该缀合物对正常组织的野性明显降低，并且抗肿瘤剂更可控地进入“特洛伊”。基于体外和体内分析，这种 mCPP-有效载荷缀合物递送系统对富含 MMP-2/9 的肿瘤具有提高的选择性，将成为肿瘤靶向治疗的有前途的策略。
