Cassioli Maria Letizia, Fay Michael, Turyanska Lyudmila, Bradshaw Tracey D, Thomas Neil R, Pordea Anca
Faculty of Engineering, University of Nottingham NG7 2RD UK
Nanoscale and Microscale Research Centre, University of Nottingham NG7 2RD UK.
RSC Adv. 2024 Apr 29;14(20):14008-14016. doi: 10.1039/d3ra07430g. eCollection 2024 Apr 25.
Protein capsules are promising drug delivery vehicles for cancer research therapies. Apoferritin (AFt) is a self-assembling 12 nm diameter hollow nanocage with many desirable features for drug delivery, however, control of drug retention inside the protein cage remains challenging. Here we report the encapsulation of copper(ii)-1,10-phenanthroline (Cu(phen)) within the horse spleen AFt (HSAFt) nanocage, by diffusion of the metal through the pores between the protein subunits. Transmission electron microscopy revealed the formation of organised copper adducts inside HSAFt, without affecting protein integrity. These structures proved stable during storage (>4 months at -20 °C). Exposure to physiologically relevant conditions (37 °C) showed some selectivity in cargo release after 24 h at pH 5.5, relevant to the internalisation of AFt within the endosome (60% release), compared to pH 7.4, relevant to the bloodstream (40% release). Co-encapsulation of temozolomide, a prodrug used to treat glioblastoma multiforme, and Cu(phen) enabled entrapment of an average of 339 TMZ molecules per cage. results from MTT and clonogenic assays identified cytotoxic activity of the Cu(phen), HSAFt-Cu(phen) and HSAFt-Cu(phen)-TMZ adducts against colorectal cancer cells (HCT-116) and glioblastoma cells (U373V, U373M). However, the presence of the metal also contributed to more potent activity toward healthy MRC5 fibroblasts, a result that requires further investigation to assess the clinical viability of this system.
蛋白质胶囊是癌症研究治疗中很有前景的药物递送载体。脱铁铁蛋白（AFt）是一种自组装的直径为12纳米的中空纳米笼，具有许多适合药物递送的特性，然而，控制药物在蛋白质笼内的保留仍然具有挑战性。在此，我们报告通过金属扩散穿过蛋白质亚基之间的孔隙，将铜（II）-1,10-菲咯啉（Cu(phen)）封装在马脾AFt（HSAFt）纳米笼内。透射电子显微镜显示在HSAFt内部形成了有组织的铜加合物，而不影响蛋白质的完整性。这些结构在储存期间（-20°C下>4个月）被证明是稳定的。暴露于生理相关条件（37°C）下，在pH 5.5（与AFt在内体中的内化相关）时，24小时后货物释放具有一定选择性（60%释放），相比之下，在pH 7.4（与血流相关）时为40%释放。替莫唑胺是一种用于治疗多形性胶质母细胞瘤的前药，与Cu(phen)共同封装能够使每个笼子平均捕获339个替莫唑胺分子。MTT和克隆形成试验的结果确定了Cu(phen)、HSAFt-Cu(phen)和HSAFt-Cu(phen)-替莫唑胺加合物对结肠癌细胞（HCT-116）和胶质母细胞瘤细胞（U373V、U373M）的细胞毒性活性。然而，金属的存在也导致对健康的MRC5成纤维细胞具有更强的活性，这一结果需要进一步研究以评估该系统的临床可行性。
