纳米颗粒递送 miR-21-3p 通过促进铁死亡使黑色素瘤对抗 PD-1 免疫治疗敏感。

BACKGROUND: Although anti-programmed cell death protein 1 (PD-1) immunotherapy is greatly effective in melanoma treatment, low response rate and treatment resistance significantly hinder its efficacy. Tumor cell ferroptosis triggered by interferon (IFN)-γ that is derived from tumor-infiltrating CD8 T cells greatly contributes to the effect of immunotherapy. However, the molecular mechanism underlying IFN-γ-mediated ferroptosis and related potentially promising therapeutic strategy warrant further clarification. MicroRNAs (miRNAs) participate in ferroptosis execution and can be delivered systemically by multiple carriers, which have manifested obvious therapeutic effects on cancer. METHODS: MiRNAs expression profile in IFN-γ-driven ferroptosis was obtained by RNA sequencing. Biochemical assays were used to clarify the role of miR-21-3p in IFN-γ-driven ferroptosis and the underlying mechanism. MiR-21-3p-loaded gold nanoparticles were constructed and systemically applied to analyze the role of miR-21-3p in anti-PD-1 immunotherapy in preclinical transplanted tumor model. RESULTS: MiRNAs expression profile of melanoma cells in IFN-γ-driven ferroptosis was first obtained. Then, upregulated miR-21-3p was proved to facilitate IFN-γ-mediated ferroptosis by potentiating lipid peroxidation. miR-21-3p increased the ferroptosis sensitivity by directly targeting thioredoxin reductase 1 (TXNRD1) to enhance lipid reactive oxygen species (ROS) generation. Furthermore, miR-21-3p overexpression in tumor synergized with anti-PD-1 antibody by promoting tumor cell ferroptosis. More importantly, miR-21-3p-loaded gold nanoparticles were constructed, and the systemic delivery of them increased the efficacy of anti-PD-1 antibody without prominent side effects in preclinical mice model. Ultimately, ATF3 was found to promote miR-21-3p transcription in IFN-γ-driven ferroptosis. CONCLUSIONS: MiR-21-3 p upregulation contributes to IFN-γ-driven ferroptosis and synergizes with anti-PD-1 antibody. Nanoparticle delivery of miR-21-3 p is a promising therapeutic approach to increase immunotherapy efficacy without obvious systemic side effects.

背景：尽管抗程序性细胞死亡蛋白 1（PD-1）免疫疗法在黑色素瘤治疗中非常有效，但低反应率和治疗耐药性极大地阻碍了其疗效。源自肿瘤浸润性 CD8 T 细胞的干扰素（IFN）-γ引发的肿瘤细胞铁死亡极大地促进了免疫疗法的效果。然而，IFN-γ 介导的铁死亡的分子机制以及相关的潜在有前途的治疗策略需要进一步阐明。微小 RNA（miRNA）参与铁死亡的执行，并且可以通过多种载体系统传递，这对癌症表现出明显的治疗效果。

方法：通过 RNA 测序获得 IFN-γ 驱动的铁死亡中 miRNA 的表达谱。生物化学测定用于阐明 miR-21-3p 在 IFN-γ 驱动的铁死亡中的作用及其潜在机制。构建负载 miR-21-3p 的金纳米颗粒，并在临床前移植肿瘤模型中系统应用以分析 miR-21-3p 在抗 PD-1 免疫治疗中的作用。

结果：首次获得 IFN-γ 驱动的铁死亡中黑色素瘤细胞的 miRNAs 表达谱。然后，上调的 miR-21-3p 通过增强脂质过氧化作用促进 IFN-γ 介导的铁死亡。miR-21-3p 通过直接靶向硫氧还蛋白还原酶 1（TXNRD1）增强脂质活性氧（ROS）生成来增加铁死亡敏感性。此外，肿瘤中的 miR-21-3p 过表达通过促进肿瘤细胞铁死亡与抗 PD-1 抗体协同作用。更重要的是，构建了负载 miR-21-3p 的金纳米颗粒，并且它们的全身递送在临床前小鼠模型中增加了抗 PD-1 抗体的疗效而没有明显的副作用。最终，发现 ATF3 在 IFN-γ 驱动的铁死亡中促进 miR-21-3p 的转录。

结论：miR-21-3p 的上调有助于 IFN-γ 驱动的铁死亡，并与抗 PD-1 抗体协同作用。miR-21-3p 的纳米颗粒递送是一种很有前途的治疗方法，可以在不产生明显全身副作用的情况下提高免疫治疗的疗效。