Screening and characterization of a novel high‐efficiency tumor‐homing cell‐penetrating peptide from the buffalo cathelicidin family

• Published in: Journal of peptide science 2019-09, Vol.25 (9), p.e3201-n/a
• Main Authors: Xu, Yuan‐Yuan, Cao, Xue‐Wei, Fu, Long‐Yun, Zhang, Tao‐Zhu, Wang, Fu‐Jun, Zhao, Jian
• Format: Article
• Language: English
• Subjects: Animals; Antimicrobial agents; Antimicrobial Cationic Peptides - chemistry; Antimicrobial Cationic Peptides - isolation & purification; Antimicrobial Cationic Peptides - metabolism; Antimicrobial peptides; Antineoplastic Agents - chemistry; Antineoplastic Agents - pharmacology; Apoptosis; Apoptosis - drug effects; Biocompatibility; Biotechnology; Buffaloes; cathelicidin; Cell Proliferation - drug effects; Cell Survival - drug effects; Cells, Cultured; cell‐penetrating peptide; Conjugation; Cytotoxicity; Dose-Response Relationship, Drug; Drug carriers; Drug Carriers - chemistry; Drug Carriers - isolation & purification; Drug Carriers - metabolism; Drug delivery; Drug Delivery Systems; Drug development; Drug Evaluation, Preclinical; Drug Screening Assays, Antitumor; Efficiency; Embryos; Flow cytometry; Fluorescence; Fusion protein; Hepatoma; Homing; Humans; Lungs; MAP 30; Peptides; Proteins; Structure-Activity Relationship; Therapy; Toxicity; Translocation; Tumor cell lines; Tumor cells; Tumors; tumor‐homing peptide
• ISSN: 1075-2617; 1099-1387
• DOI: 10.1002/psc.3201

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. We identified a highly efficient tumor‐homing cell‐penetrating peptide, CAT, from the newly identified buffalo‐derived cathelicidin family, which exhibits a preferential binding capacity for multiple tumor cells and delivers carried drug molecules into cells. CAT has great potential in drug delivery for cancer therapy.