The Anti-Cancer Potency and Mechanism of a Novel Tumor-Activated Fused Toxin, DLM

Toxins

Dejun Sun¹  Miaonan Sun¹  Wenhe Zhu²  Zhiding Wang¹  Yuefei Li¹  Jie Ma³ 

[1] Department of Biomedicine, Institute for Regeneration Medicine, Jilin University, Changchun 130021, China; E-Mails:;Department of Biochemistry, School of Basic Medicine, Jilin Medical College, Jilin 130000, China; E-Mail:;School of Pharmaceutical Sciences, Jilin University, Changchun 130021, China

关键词: tumor-activated;    fused toxin;    disintegrin;    melittin;    anti-cancer;   

DOI  :  10.3390/toxins7020423

来源: mdpi

【 摘 要 】

Melittin, which acts as a membrane-disrupting lytic peptide, is not only cytotoxic to tumors, but also vital to normal cells. Melittin had low toxicity when coupled with target peptides. Despite significant research development with the fused toxin, a new fused toxin is needed which has a cleavable linker such that the fused toxin can release melittin after protease cleavage on the tumor cell surface. We describe a novel fused toxin, composed of disintegrin, uPA (urokinase-type plasminogen activator)-cleavable linker, and melittin. Disintegrin is a single strand peptide (73 aa) isolated from Gloydius Ussuriensis venom. The RGD (Arg-Gly-Asp) site of disintegrin dominates its interaction with integrins on the surface of the tumor cells. uPA is over-expressed and plays an important role in tumor cell invasiveness and metastatic progression. The DLM (disintegrin-linker-melittin) linker is uPA-cleavable, enabling DLM to release melittin. We compared binding activity of our synthesized disintegrin with native disintegrin and report that DLM had less binding activity than the native form. uPA-cleavage was evaluated in vitro and the uPA-cleavable linker released melittin. Treating tumors expressing uPA with DLM enhanced tumor cell killing as well as reduced toxicity to erythrocytes and other non-cancerous normal cells. The mechanism behind DLM tumor cell killing was tested using a DNA ladder assay, fluorescent microscopy, flow cytometry, and transmission electron microscopy. Data revealed tumor cell necrosis as the mechanism of cell death, and the fused DLM toxin with an uPA-cleavable linker enhanced tumor selectivity and killing ability.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.