KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea; Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea.
Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea.
Biomaterials. 2021 May;272:120791. doi: 10.1016/j.biomaterials.2021.120791. Epub 2021 Apr 1.
The effective chemotherapeutic drug, doxorubicin (DOX), elicits immunogenic cell death (ICD) and additional anticancer immune responses during chemotherapy. However, it also induces severe side effects and systemic immunosuppression, hampering its wide clinical application. Herein, we constructed cancer-activated DOX prodrug by conjugating the cathepsin B-cleavable peptide (Phe-Arg-Arg-Gly, FRRG) to a doxorubicin (DOX), resulting in FRRG-DOX that self-assembled into cancer-activated DOX prodrug nanoparticles (CAP-NPs). The resulting CAP-NPs were further stabilized with the FDA-approved compound, Pluronic F68. CAP-NPs formed stable prodrug nanoparticles and they were specifically cleaved to cytotoxic DOX molecules only in cathepsin B-overexpressing cancer cells, inducing a cancer cell-specific cytotoxicity. In particular, the CAP-NPs induced ICD through cathepsin B-cleavage mechanism only in targeted cancer cells in vitro. In colon tumor-bearing mice, selectively accumulated CAP-NPs at tumors enhanced antitumor immunity without DOX-related severe toxicity, inflammatory response and systemic immunosuppression. Moreover, cytotoxicity against immune cells infiltrated into tumor microenvironment was significantly reduced compared to free DOX, leading to increased response to checkpoint inhibitor immunotherapy. The combinatorial treatment of CAP-NPs with anti-PD-L1 exhibited high rate of complete tumor regression (50%) compared to free DOX with anti-PD-L1. Concurrently, DOX-related side effects were greatly reduced during chemoimmunotherapy. Collectively, our results suggest that cancer-activated DOX prodrug nanoparticles provide a promising approach to increase clinical benefit by inducing an immune response preferentially only to targeted cancer cells, not to normal cells and immune cells, and potentiates checkpoint inhibitor immunotherapy.
有效化疗药物多柔比星（DOX）在化疗过程中引发免疫原性细胞死亡（ICD）和额外的抗癌免疫反应。然而，它也会引起严重的副作用和全身免疫抑制，阻碍其广泛的临床应用。在此，我们通过将组织蛋白酶 B 可切割肽（Phe-Arg-Arg-Gly，FRRG）与多柔比星（DOX）偶联构建了癌症激活的 DOX 前药，得到自组装成癌症激活 DOX 前药纳米颗粒（CAP-NPs）的 FRRG-DOX。所得 CAP-NPs 进一步用 FDA 批准的化合物 Pluronic F68 稳定化。CAP-NPs 形成稳定的前药纳米颗粒，仅在组织蛋白酶 B 过表达的癌细胞中特异性切割成细胞毒性 DOX 分子，诱导癌细胞特异性细胞毒性。特别是，CAP-NPs 通过仅在靶向癌细胞中通过组织蛋白酶 B 切割机制诱导 ICD 在体外。在结肠荷瘤小鼠中，选择性地在肿瘤中积累 CAP-NPs 增强了抗肿瘤免疫，而没有与 DOX 相关的严重毒性、炎症反应和全身免疫抑制。此外，与游离 DOX 相比，对浸润肿瘤微环境的免疫细胞的细胞毒性显著降低，导致对检查点抑制剂免疫治疗的反应增加。CAP-NPs 与抗 PD-L1 的联合治疗与游离 DOX 与抗 PD-L1 的联合治疗相比，完全肿瘤消退率（50%）更高。同时，在化疗免疫治疗过程中大大减少了 DOX 相关的副作用。总之，我们的结果表明，癌症激活的 DOX 前药纳米颗粒通过仅诱导针对靶向癌细胞的免疫反应，而不是针对正常细胞和免疫细胞，提供了一种有前途的方法来增加临床获益，并增强检查点抑制剂免疫治疗。
