Department of Pharmacy, Birla Institute of Technology & Science-Pilani, Hyderabad Campus, Jawahar Nagar, Medchal, Hyderabad, Telangana, 500078, India.
Pharm Res. 2020 Jan 2;37(2):18. doi: 10.1007/s11095-019-2750-0.
In this study, we developed a polymeric micellar system for glutathione-mediated intracellular delivery of a photosensitizer, chlorin e6 (Ce6) by synthesizing an amphiphilic polymer, methoxy-poly(ethylene glycol)-poly(D,L-lactide)-disulfide-Ce6 (mPEG-PLA-S-S-Ce6), which self-assembled in aqueous environment to form micelles.
The polymer-drug conjugate was characterized by NMR. The singlet oxygen (O) generation and in vitro release of Ce6 micelles were evaluated. Further, glutathione-mediated intracellular drug delivery was assessed in human alveolar adenocarcinoma cells (A549), mouse mammary carcinoma cells (4 T1) and 3D A549 spheroids.
The micellar system protected Ce6 from aggregation leading to improved O generation compared to free Ce6. Due to the availability of glutathione, the disulfide bonds in the micelles were cleaved resulting in rapid release of Ce6 evident from the in vitro study. The Ce6 micelles displayed quicker drug release in presence of glutathione monoester (GSH-OEt) pre-treated A549 and 4 T1 cells compared to without pre-treated cells. In vitro phototoxicity of micelles displayed enhanced toxicity in 10 mM GSH-OEt pre-treated A549 and 4 T1 cells compared to untreated cells. As anticipated, Ce6 micelles showed lower drug release in presence of 0.1 mM of buthionine sulfoximine (BSO) pretreated A549 and 4 T1 cells exhibiting lower phototoxicity. Further, A549 3D spheroids treated with Ce6 micelles showed significant inhibition in growth, enhanced phototoxicity, and cellular apoptosis in comparison to free Ce6.
The above results showed that the developed strategy could be effective in improving the PDT efficacy of Ce6, and the developed polymeric micellar system could be utilized as a PDT regimen for cancer.
在这项研究中，我们通过合成一种两亲性聚合物，即甲氧基聚（乙二醇）-聚（D，L-丙交酯）-二硫代-氯己定（mPEG-PLA-S-S-Ce6），制备了一种谷胱甘肽介导的细胞内递药的聚合物胶束系统，用于将光敏剂氯己定（Ce6）递送至细胞内。
通过 NMR 对聚合物-药物偶联物进行了表征。评估了单线态氧（O）的产生和 Ce6 胶束的体外释放。此外，在人肺泡腺癌细胞（A549）、小鼠乳腺癌细胞（4T1）和 3D A549 球体中评估了谷胱甘肽介导的细胞内药物递送。
胶束系统保护 Ce6 免于聚集，从而与游离 Ce6 相比，产生了更多的 O。由于谷胱甘肽的存在，胶束中的二硫键被切断，导致 Ce6 的快速释放，这从体外研究中可以明显看出。与未经预处理的细胞相比，在含有谷胱甘肽单酯（GSH-OEt）预处理的 A549 和 4T1 细胞中，Ce6 胶束显示出更快的药物释放。与未经处理的细胞相比，在 10 mM GSH-OEt 预处理的 A549 和 4T1 细胞中，胶束的体外光毒性显示出更强的毒性。正如预期的那样，在含有 0.1 mM 丁硫氨酸亚砜（BSO）预处理的 A549 和 4T1 细胞中，Ce6 胶束的药物释放较低，表现出较低的光毒性。此外，与游离 Ce6 相比，用 Ce6 胶束处理的 A549 3D 球体在生长抑制、增强的光毒性和细胞凋亡方面表现出显著的抑制作用。
上述结果表明，所开发的策略可有效提高 Ce6 的 PDT 疗效，所开发的聚合物胶束系统可用于癌症的 PDT 方案。
