Key Laboratory for Advanced Materials, School of Chemistry and Molecular Engineering , East China University of Science and Technology , Shanghai 200237 , PR China.
Key Laboratory of Medical Molecular Virology (MOE & MOH), School of Basic Medical Sciences , Fudan University , Shanghai 200032 , PR China.
Langmuir. 2018 Jul 31;34(30):8818-8827. doi: 10.1021/acs.langmuir.8b00474. Epub 2018 Jul 11.
Antitumor peptides may potentially alleviate the problem of chemoresistance but do not yet target tumor cells and would be cytotoxic to normal cells. Here, we designed a pH-activated and thermosensitive lipopeptide (C6-Pep) containing a leucine zipper and an alkyl chain and assessed the ability of C6-Pep to kill cancer cells. Pep, the same sequence without the N-terminal hexanoic acid moiety, was generated as a less hydrophobic control. First, lipopeptide adsorption into lipid monolayers was studied using Langmuir-Blodgett and polarization modulation infrared reflection adsorption spectroscopy. Under weakly acid conditions, electrostatic interactions between C6-Pep and negatively charged phospholipids increased the adsorption/insertion of C6-Pep (vs Pep) into lipid monolayers. Cargo leakage from liposomes was assayed to model lipopeptide-induced lipid membrane disruption. The ability of C6-Pep to disrupt liposomes depended on the peptide molecular structure/hydrophobicity, solution pH, and temperature-induced uncoiling of the zipper structure; the greatest cargo leakage from the liposome with negative charge was observed for C6-Pep at pH 5.5 under mildly hyperthermic conditions (45 °C). In vitro, C6-Pep was significantly more cytotoxic toward HeLa cells at pH 5.5 under hyperthermic conditions than at pH 7.4 and/or 37 °C. Overall, this study demonstrates that amphipathic C6-Pep can insert into cell membranes in the low-pH tumor microenvironment, whereas the application of heat promotes the uncoiling of the zipper structure, leading to the disruption of tumor cell membranes and cell death. pH-activated and thermosensitive C6-Pep represents a promising tool to kill cancer cells via a strategy that does not invoke chemoresistance and may have low side effects.
抗肿瘤肽可能有潜力缓解化疗耐药问题，但它们目前还不能靶向肿瘤细胞，而且对正常细胞具有细胞毒性。在这里，我们设计了一种包含亮氨酸拉链和烷基链的 pH 激活和温敏脂质肽（C6-Pep），并评估了 C6-Pep 杀死癌细胞的能力。生成了与 Pep 相同但没有 N 端己酸部分的肽作为疏水性较低的对照。首先，使用 Langmuir-Blodgett 和偏振调制红外反射吸附光谱研究了脂质肽的吸附到脂质单层上。在弱酸性条件下，C6-Pep 与带负电荷的磷脂之间的静电相互作用增加了 C6-Pep（与 Pep 相比）在脂质单层中的吸附/插入。通过测定脂质体中的货物泄漏来模拟脂质肽诱导的脂质膜破坏。C6-Pep 破坏脂质体的能力取决于肽的分子结构/疏水性、溶液 pH 值以及拉链结构的温度诱导解卷曲；在 pH 值为 5.5 且温度轻度升高（45°C）的条件下，带负电荷的脂质体中观察到最大的货物泄漏。在体外，与 pH 值为 7.4 和/或 37°C 相比，C6-Pep 在 pH 值为 5.5 且高温条件下对 HeLa 细胞的细胞毒性显著增强。总的来说，这项研究表明，两亲性 C6-Pep 可以在低 pH 值的肿瘤微环境中插入细胞膜，而热的应用促进了拉链结构的解卷曲，导致肿瘤细胞膜的破坏和细胞死亡。pH 激活和温敏的 C6-Pep 代表了一种通过不引发化疗耐药的策略杀死癌细胞的有前途的工具，并且可能具有较低的副作用。
