Abstract：
Stimuli-responsive cross-linked nanocarriers that can induce lysosomal cell death (LCD) via lysosomal membrane permeabilization (LMP) represent a new class of delivery platforms and have attracted the attention of researchers in the biomedical field. The advantages of such cross-linked nanocarriers are as follows (i) they remain intact during blood circulation; and (ii) they reach the target site via specific receptor-mediated endocytosis leading to the enhancement of therapeutic efficacy and reduction of side effects. Herein, we have synthesized a mannose-6-phosphate (M6P) based amphiphilic ABC type tri-block copolymer having two chains of FDA-approved poly(ε-caprolactone) (PCL) as the hydrophobic block, and poly(S-(o-nitrobenzyl)-L-cysteine) (NBC) acts as the photoresponsive crosslinker block. Two different tri-block copolymers, [(PCL35)2-b-NBC20-b-M6PGP20] and [(PCL35)2-b-NBC15-b-M6PGP20], were synthesized which upon successful self-assembly initially formed spherical uncross-linked \"micellar-type\" aggregates (UCL-M) and vesicles (UCL-V), respectively. The uncross-linked nanocarriers upon UV treatment for thirty minutes were covalently crosslinked in the middle PNBC block giving rise to the di-sulfide bonds and forming interface cross-linked \"micellar-type\" aggregates (ICL-M) and vesicles (ICL-V). DLS, TEM, and AFM techniques were used to successfully characterize the morphology of these nanocarriers. The dual stimuli (redox and enzyme) responsiveness of the cross-linked nanocarriers and their trafficking to the lysosome in mammalian cells via receptor-mediated endocytosis was probed using confocal microscopy images. Furthermore, the addition of a chloroquine (CQ, a known lysosomotropic agent) encapsulated cross-linked nanocarrier (CQ@ICL-V) to non-cancerous (HEK-293T) cells and liver (HepG2), and breast cancer cells (MDA-MB-231) was found to initiate lysosomal membrane permeabilization (LMP) followed by lysosomal destabilization which eventually led to lysosomal cell death (LCD). Due to the targeted delivery of CQ to the lysosomes of cancerous cells, almost a 90% smaller amount of CQ was able to achieve similar cell death to CQ alone.
摘要：
可以通过溶酶体膜透化（LMP）诱导溶酶体细胞死亡（LCD）的刺激响应性交联纳米载体代表了一类新的递送平台，并引起了生物医学领域研究人员的关注。这样的交联纳米载体的优点如下:(i)它们在血液循环期间保持完整;和(ii)它们通过特异性受体介导的内吞作用到达靶位点,导致治疗功效的增强和副作用的减少。在这里，我们合成了基于甘露糖-6-磷酸（M6P）的两亲性ABC型三嵌段共聚物，该共聚物具有FDA批准的聚（ε-己内酯）（PCL）的两条链作为疏水嵌段，和聚(S-(o-硝基苄基)-L-半胱氨酸)(NBC)充当光响应性交联剂嵌段。两种不同的三嵌段共聚物，[(PCL35)2-b-NBC20-b-M6PGP20]和[(PCL35)2-b-NBC15-b-M6PGP20]，合成了成功的自组装后，最初形成球形未交联的“胶束型”聚集体（UCL-M）和囊泡（UCL-V），分别。紫外线处理30分钟后，未交联的纳米载体在中间PNBC嵌段中共价交联，产生二硫键，并形成界面交联的“胶束型”聚集体（ICL-M）和囊泡（ICL-V）。DLS,TEM,和AFM技术被用来成功地表征这些纳米载体的形态。使用共聚焦显微镜图像探测交联纳米载体的双重刺激(氧化还原和酶)响应性及其通过受体介导的内吞作用向哺乳动物细胞中的溶酶体的运输。此外，添加氯喹(CQ，一种已知的溶酶体化剂）将交联纳米载体（CQ@ICL-V）封装到非癌性（HEK-293T）细胞和肝脏（HepG2），发现乳腺癌细胞（MDA-MB-231）启动溶酶体膜透化（LMP），然后是溶酶体不稳定，最终导致溶酶体细胞死亡（LCD）。由于CQ靶向递送到癌细胞的溶酶体,与单独CQ相比,几乎90%的CQ能够实现类似的细胞死亡。
