A Clickable and Photocleavable Lipid Analogue for Cell Membrane Delivery and Release
作者:Shahrina Alam、Daiane S. Alves、Stuart A. Whitehead、Andrew M. Bayer、Christopher D. McNitt、Vladimir V. Popik、Francisco N. Barrera、Michael D. Best
DOI:10.1021/acs.bioconjchem.5b00044
日期:2015.6.17
For drug delivery purposes, the ability to conveniently attach a targeting moiety that will deliver drugs to cells and then enable controlled release of the active molecule after localization is desirable. Toward this end, we designed and synthesized clickable and photocleavable lipid analogue 1 to maximize the efficiency of bioconjugation and triggered release. This compound contains a dibenzocyclooctyne group for bioorthogonal derivatization linked via a photocleavable 2-nitrobenzyl moiety at the headgroup of a synthetic lipid backbone for targeting to cell membranes. To assess delivery and release using this system, we report fluorescence-based assays for liposomal modification and photocleavage in solution as well as through surface immobilization to demonstrate successful liposome functionalization and photoinduced release. In addition, fluorophore delivery to and release from live cells was confirmed and characterized using fluorescence microscopy and flow cytometry analysis in which 1 was delivered to cells, derivatized, and photocleaved. Finally, drug delivery studies were performed using an azide-tagged analogue of camptothecin, a potent anticancer drug that is challenging to deliver due to poor solubility. In this case, the ester attachment of the azide tag acted as a caging group for release by intracellular esterases rather than through photocleavage. This resulted in a dose-dependent response in the presence of liposomes containing delivery agent 1, confirming the ability of this compound to stimulate delivery to the cytoplasm of cells.
为了实现药物递送的目的,能够方便地附加一个靶向部分,将药物递送至细胞,并在定位后实现活性分子的可控释放,这是可取的。为此,我们设计并合成了可点击且光裂解的脂质类似物1,以最大限度地提高生物共轭和触发释放的效率。该化合物包含一个通过光裂解的2-硝基苄基部分连接的二苯并环辛炔基团,位于合成脂质骨架的头部,用于靶向细胞膜。为了评估该系统的递送和释放,我们报道了基于荧光的脂质体修饰和溶液中以及通过表面固定化的光裂解实验,以证明成功实现脂质体功能化和光诱导释放的证据。此外,通过荧光显微镜和流式细胞术分析确认并表征了荧光团向活细胞的递送和释放,其中1被递送至细胞、衍生化并光裂解。最后,使用了一种带有叠氮标记的喜树碱类似物进行药物递送研究,喜树碱是一种具有强抗癌活性的药物,但由于其溶解性差而难以递送。在这种情况下,叠氮标签的酯键连接起到了笼蔽基团的作用,通过细胞内酯酶的释放而不是光裂解。结果显示,在含有递送剂1的脂质体存在下,剂量依赖性响应得到了确认,证实了该化合物刺激细胞质内部递送的能力。