Veloria John R, Chen Luxi, Li Lin, Breen Gail A M, Lee Jiyong, Goux Warren J
Department of Biological Sciences , The University of Texas at Dallas , 800 W. Campbell Rd , Richardson , TX 75080 , USA.
Department of Chemistry and Biochemistry , The University of Texas at Dallas , 800 W. Campbell Rd , Richardson , TX 75080 , USA . Email:
Medchemcomm. 2017 Dec 5;9(1):121-130. doi: 10.1039/c7md00321h. eCollection 2018 Jan 1.
The goal of this study was to develop a peptide which could use the toxic effects of amyloid, a substance which is the hallmark of over 25 known human diseases, to selectively kill cancer cells. Here we demonstrate that two separate amyloid-forming hexapeptides, one from the microtubule associated protein Tau involved in formation of paired helical filaments of Alzheimer's disease, and the other an amyloid forming sequence from apolipoprotein A, when conjugated to a cell penetrating peptide (CPP) sequence, form toxic oligomers which are stable for up to 14 h and able to enter cells by a combination of endocytosis and transduction. The amyloid peptide conjugates showed selective cytotoxicity to breast cancer, neuroblastoma and cervical cancer cells in culture compared to normal cells. Fluorescence imaging experiments showed the CPP-amyloid peptide oligomers formed intracellular fibrous amyloid, visible in the endosomes/lysosomes, cytosol and nucleus with thioflavin S (ThS) staining. Further experiments with rhodamine-conjugated Dextran, propidium iodide (PI), and acridine orange (AO) suggested the mechanism of cell death was the permeability of the lysosomal membrane brought about by the formation of amyloid pores. Cytotoxicity could be abrogated by inhibitors of lysosomal hydrolases, consistent with a model where lysosomal hydrolases leak into the cytosol and induce cytotoxicity in subsequent downstream steps. Taken together, our data suggest that CPP-amyloid peptide conjugates show potential as a new class of anti-cancer peptides (ACPs).
本研究的目标是开发一种肽，该肽可利用淀粉样蛋白的毒性作用来选择性杀死癌细胞。淀粉样蛋白是超过25种已知人类疾病的标志物质。在此我们证明，两种不同的形成淀粉样蛋白的六肽，一种来自参与阿尔茨海默病成对螺旋丝形成的微管相关蛋白Tau，另一种来自载脂蛋白A的淀粉样蛋白形成序列，当与细胞穿透肽（CPP）序列缀合时，会形成毒性寡聚物，这些寡聚物在长达14小时内保持稳定，并能够通过内吞作用和转导作用的组合进入细胞。与正常细胞相比，淀粉样肽缀合物在培养物中对乳腺癌、神经母细胞瘤和宫颈癌细胞表现出选择性细胞毒性。荧光成像实验表明，CPP-淀粉样肽寡聚物在细胞内形成纤维状淀粉样蛋白，用硫黄素S（ThS）染色可在内体/溶酶体、细胞质和细胞核中看到。用罗丹明缀合的葡聚糖、碘化丙啶（PI）和吖啶橙（AO）进行的进一步实验表明，细胞死亡的机制是淀粉样蛋白孔的形成导致溶酶体膜通透性增加。溶酶体水解酶抑制剂可消除细胞毒性，这与溶酶体水解酶泄漏到细胞质中并在随后的下游步骤中诱导细胞毒性的模型一致。综上所述，我们的数据表明，CPP-淀粉样肽缀合物作为一类新型抗癌肽（ACP）具有潜力。
