State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China.
Zhejiang Fonow Medicine Co. Ltd., Dongyang City, China.
J Pept Sci. 2019 Sep;25(9):e3201. doi: 10.1002/psc.3201. Epub 2019 Jul 15.
Targeted delivery of antitumor drugs is especially important for tumor therapy. Cell-penetrating peptides (CPPs) have been shown to be very effective drug carriers for tumor therapy. However, most CPPs lack tumor cell specificity. Here, we identified a highly efficient CPP, CAT, from the newly identified buffalo-derived cathelicidin family, which exhibits a preferential binding capacity for multiple tumor cell lines and delivers carried drug molecules into cells. CAT showed an approximately threefold to sixfold higher translocation efficiency than some reported cell-penetrating antimicrobial peptides, including the well-known classical CPP TAT. Moreover, the delivery efficiency of CAT was greater in a variety of tested tumor cells than in normal cells, especially for the human hepatoma cell line SMMC-7721, for which delivery was 7 times more efficient than the normal human embryonic lung cell line MRC-5, according to fluorescent labeling experiment results. CAT was conjugated to the Momordica charantia-derived type-I ribosome-inactivating protein MAP 30, and the cytotoxicity of the MAP 30-CAT fusion protein in the tumor cell line SMMC-7721 was significantly enhanced compared with that of the unconjugated MAP 30. The IC50 value of MAP 30-CAT was approximately 83 times lower than the IC50 value of the original MAP 30. Interestingly, the IC50 value of MAP 30 alone for MRC-5 was approximately twofold higher than the value for SMMC-7721, showing a small difference. However, when MAP 30 was conjugated to CAT, the difference in IC50 values between the two cell lines was significantly increased by 38-fold. The results of the flow cytometric detection of apoptosis revealed that the increase in cytotoxicity after CAT conjugation was mainly caused by the increased induction of apoptosis by the fusion protein. These results suggest that CAT, as a novel tumor-homing CPP, has great potential in drug delivery applications in vivo and will be beneficial to the development of tumor therapeutics.
靶向递送抗肿瘤药物对肿瘤治疗尤为重要。细胞穿透肽（CPPs）已被证明是非常有效的肿瘤治疗药物载体。然而，大多数 CPP 缺乏肿瘤细胞特异性。在这里，我们从新发现的水牛源抗菌肽家族中鉴定出一种高效的 CPP，CAT，它对多种肿瘤细胞系具有优先的结合能力，并将携带的药物分子递送入细胞。CAT 的转位效率比一些报道的细胞穿透性抗菌肽高约 3 倍至 6 倍，包括著名的经典 CPP TAT。此外，根据荧光标记实验结果，CAT 在各种测试的肿瘤细胞中的递送效率均高于正常细胞，尤其是对人肝癌细胞系 SMMC-7721，其递送效率比正常的人胚肺成纤维细胞系 MRC-5 高 7 倍。CAT 与苦瓜衍生的 I 型核糖体失活蛋白 MAP 30 缀合，与未缀合的 MAP 30 相比，MAP 30-CAT 融合蛋白在肿瘤细胞系 SMMC-7721 中的细胞毒性显著增强。MAP 30-CAT 的 IC50 值约为原始 MAP 30 的 IC50 值的 83 倍。有趣的是，MAP 30 对 MRC-5 的 IC50 值约为 SMMC-7721 的两倍，差异较小。然而，当 MAP 30 与 CAT 缀合时，两种细胞系之间 IC50 值的差异显著增加了 38 倍。凋亡的流式细胞术检测结果表明，CAT 缀合后细胞毒性的增加主要是由于融合蛋白诱导凋亡的增加。这些结果表明，CAT 作为一种新型的肿瘤归巢 CPP，在体内药物递送应用中具有巨大潜力，将有利于肿瘤治疗的发展。
