Inhibition of tumor-intrinsic NAT10 enhances antitumor immunity by triggering type I interferon responses via MYC/CDK2/DNMT1 pathway. Inhibition of tumor-intrinsic NAT10 enhances antitumor immunity by triggering type I interferon responses via MYC/CDK2/DNMT1 pathway

Purpose:Posttranscriptional modifications are deeply involved in cancer progression; however, there remains knowledge gap regarding the function and immune regulatory mechanism of newly discovered mRNA acetylation modification.Methods: The expression of NAT10 in human tumor tissues was analyzed based on TCGA data. NAT10 knockout murine cell lines were generated to analyze the NAT10-associated tumor progression and anti-tumor immune response in tumor xenograft models. Immune cells and cytokines in TME were quantified by immunofluorescence, flow cytometry, quantitative reverse transcription-PCR, and ELISPOT assay. NAT10-associated differentially expressed genes were investigated in cancer cells and tissues with RNA-Seq. Results:Loss of tumoral NAT10 significantly stimulated tumor-specific cellular immune responses and suppressed tumor growth. Mechanistically, we identified MYC as a key downstream target of NAT10 via enhancing mRNA stability and translation efficiency. Inhibition of NAT10 blocked the MYC/CDK2/DNMT1 pathway, subsequently enhancing double-stranded RNAs (dsRNA) formation, which triggered type I interferon responses to enhance the in vivo response of tumor specific CD8+ T cells. Conclusions: Inhibition of NAT10 using either small molecule inhibitor (Remodelin) or PEI/PC7A/siNAT10 nanoparticles combined with PD-1 blockade synergistically enhanced the anti-tumor immune response and repressed tumor progression. Our findings uncovered the crucial role of tumor-intrinsic NAT10 in tumor immune microenvironment, representing a promising target for enhancing cancer immunotherapy. Overall design: mRNA profiles of MCA205 and TC1 wild type (WT) and sgNAT10 cell lines; mRNA profiles of TC1 wild type (WT) and sgNAT10 tumor tissue.

研究目的：转录后修饰深度参与癌症进展过程，但针对新发现的mRNA乙酰化修饰的功能及其免疫调控机制，目前仍存在认知空白。
研究方法：本研究基于癌症基因组图谱（The Cancer Genome Atlas, TCGA）数据，分析人肿瘤组织中NAT10的表达水平；构建NAT10敲除的小鼠细胞系，在肿瘤异种移植模型中探究NAT10相关的肿瘤进展与抗肿瘤免疫应答。通过免疫荧光染色、流式细胞术、定量反转录聚合酶链反应（quantitative reverse transcription-PCR, qRT-PCR）、酶联免疫斑点试验（ELISPOT）对肿瘤微环境（Tumor Microenvironment, TME）中的免疫细胞与细胞因子进行定量检测；采用RNA测序（RNA-Seq）分析癌细胞及组织中与NAT10相关的差异表达基因。
研究结果：肿瘤细胞NAT10缺失可显著激活肿瘤特异性细胞免疫应答，并抑制肿瘤生长。机制层面，本研究通过增强mRNA稳定性与翻译效率，确定MYC为NAT10的关键下游靶标。抑制NAT10可阻断MYC/CDK2/DNMT1信号通路，继而促进双链RNA（double-stranded RNA, dsRNA）的形成，进而触发I型干扰素应答，增强肿瘤特异性CD8+ T细胞的体内免疫应答。
研究结论：采用小分子抑制剂Remodelin或PEI/PC7A/siNAT10纳米颗粒联合PD-1阻断治疗，可协同增强抗肿瘤免疫应答并抑制肿瘤进展。本研究揭示了肿瘤固有NAT10在肿瘤免疫微环境中的关键调控作用，为提升癌症免疫治疗效果提供了极具潜力的干预靶点。
整体实验设计：MCA205与TC1野生型（Wild Type, WT）及sgNAT10细胞系的mRNA表达谱；TC1野生型（WT）及sgNAT10肿瘤组织的mRNA表达谱。