College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, China.
College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, China.
Acta Biomater. 2023 Oct 1;169:477-488. doi: 10.1016/j.actbio.2023.07.051. Epub 2023 Aug 1.
Potent tumor regression remains challenging due to the lack of effective targeted drug delivery into deep tumors as well as the reduced susceptibility of cancer cells to anticancer agents in hypoxic environments. Bacteria-driven drug-delivery systems are promising carriers in overcoming targeting and diffusion limits that are inaccessible for conventional antitumor drugs. In this study, probiotic facultative anaerobe Escherichia coli Nissle 1917 (EcN) was functionalized and formed self-propelled microrobots to actively deliver therapeutic drug and photosensitizer to the deep hypoxic regions of tumors. Doxorubicin (Dox) was firstly modified with cis-aconityl anhydride (CA) and terminal thiol-decorated hydrazone derivative (Hyd-SH) through dual pH-sensitive amide and imine bonds, respectively. The functionalized CA-Dox-Hyd-SH was further coordinated with photosensitizer gold nanorods (AuNRs) and then conjugated to the surface of EcN. The resulting microrobots (EcN-Dox-Au) inherited the mobility characteristics and bioactivity of native EcN. Upon the irradiation of NIR laser, the microrobots exhibited enhanced tumor accumulation and penetration into the deep hypoxia tumor site. Strikingly, after 21 days of treatment with EcN-Dox-Au formulations, complete tumor regression was achieved without relapse for at least 53 days. This self-propelled strategy utilizing bacteria-driven microrobots provides a promising paradigm for enhancing drug penetration and elevating chemosensitivity, resulting in a superior antitumor effect. STATEMENT OF SIGNIFICANCE: Self-propelled Escherichia coli Nissle 1917 (EcN) - mediated microrobots are functionalized to co-deliver therapeutic drugs and photosensitizers to the deep tumor site. Anti-tumor drug doxorubicin (Dox) was modified through dual pH-sensitive bonds on both terminals and then linked with EcN and photosensitizer gold nanorods (AuNRs) to realize tumor microenvironment acidic pH-responsive drug release. Upon irradiation with a NIR laser near the tumor site, AuNRs produced a photothermal effect which realized the superficial tumor thermal ablation and increased the permeability of the tumor cell membrane to facilitate the penetration of microrobots. Moreover, the deep penetration of microrobots also enhanced the susceptibility of the cancer cells to Dox, and realized the complete tumor regression in the established breast cancer-bearing mice without recurrence using a lower dose of drug regimen.
由于缺乏有效的靶向药物递送到深部肿瘤以及在缺氧环境中癌细胞对抗癌药物的敏感性降低，有效的肿瘤消退仍然具有挑战性。细菌驱动的药物递送系统是克服传统抗肿瘤药物无法达到的靶向和扩散限制的有前途的载体。在这项研究中，益生菌兼性厌氧菌大肠杆菌 Nissle 1917（EcN）被功能化并形成自推进的微机器人，将治疗药物和光敏剂主动递送到肿瘤的深部缺氧区域。阿霉素（Dox）首先通过双重 pH 敏感酰胺和亚胺键分别用顺式丙烯酰酐（CA）和末端巯基修饰的腙衍生物（Hyd-SH）修饰。功能化的 CA-Dox-Hyd-SH 进一步与光敏剂金纳米棒（AuNRs）配位，然后与 EcN 表面缀合。所得微机器人（EcN-Dox-Au）继承了天然 EcN 的迁移特性和生物活性。在近红外激光照射下，微机器人表现出增强的肿瘤积累和穿透到深部缺氧肿瘤部位。引人注目的是，在用 EcN-Dox-Au 制剂治疗 21 天后，完全消退了肿瘤，至少 53 天内没有复发。这种利用细菌驱动的微机器人的自推进策略为增强药物渗透和提高化学敏感性提供了一种有前途的范例，从而产生了优异的抗肿瘤效果。
自推进的大肠杆菌 Nissle 1917（EcN）介导的微机器人被功能化，以将治疗药物和光敏剂共同递送到深部肿瘤部位。抗癌药物阿霉素（Dox）通过两端的双重 pH 敏感键进行修饰，然后与 EcN 和光敏剂金纳米棒（AuNRs）连接，以实现肿瘤微环境酸性 pH 响应性药物释放。在用肿瘤部位附近的近红外激光照射时，AuNRs 产生光热效应，实现了浅表肿瘤的热消融，并增加了肿瘤细胞膜的通透性，以促进微机器人的穿透。此外，微机器人的深部穿透还增强了癌细胞对 Dox 的敏感性，并且使用较低剂量的药物方案在建立的乳腺癌荷瘤小鼠中实现了完全肿瘤消退，没有复发。
