Background:The paucity of reliable biomarkers for predicting immunotherapy efficacy in patients with advanced hepatocellular carcinoma (HCC) has emerged as a burgeoning concern with the expanding use of immunotherapy. This study endeavors to delve into the potential peripheral biomarkers capable of prognosticating efficacy in HCC patients who are poised to receive anti-PD-1 monotherapy within the phase III clinical trial, KEYNOTE394. Additionally, we sought to elucidate the underlying molecular mechanisms for resistance to immune checkpoint blockade (ICB) and propose innovative combination immunotherapy strategies for future clinical application.
Methods:Patient blood samples were collected for single-cell RNA sequencing to evaluate the immune cell signature before receiving ICB therapy. Subsequently, in vitro assays and in vivo murine model experiments were conducted to validate the mechanism that S100A9+CD14+ monocytes play a role in ICB resistance.
Results:Our study demonstrates a notable enrichment of S100A9+CD14+ monocytes in the peripheral blood of patients exhibiting suboptimal responses to anti-PD-1 therapy. Moreover, we identified the Mono_S100A9 signature as a predictive biomarker, indicative of reduced efficacy in immunotherapy and decreased survival benefits across various tumor types. Mechanistically, S100A9 activates PD-L1 transcription by directly binding to the CD274 (PD-L1) gene promoter, thereby suppressing T-cell proliferation and cytotoxicity via the PD-1/PD-L1 axis, consequently diminishing the therapeutic effectiveness of subsequent anti-PD-1 treatments. Furthermore, our in vivo studies revealed that inhibiting S100A9 can synergistically enhance the efficacy of anti-PD-1 drugs in the eradication of hepatocellular carcinoma.
Conclusions:Our study underscores the significance of S100A9+CD14+ monocytes in predicting inadequate response to ICB treatment and provides insights into the monocyte cell-intrinsic mechanisms of resistance to ICB therapy. We also propose a combined therapeutic approach to enhance ICB efficacy by targeting S100A9.
Keywords:Anti-PD-1 monotherapy; Biomarker; Hepatocellular carcinoma; S100A9+CD14+ monocyte; Single-cell RNA sequencing.

本周为大家带来的文献为发表Cancer Discov. (IF: 29.7)的” An Inflammatory Checkpoint Generated by IL1RN Splicing Offers Therapeutic Opportunity for KRAS-Mutant Intrahepatic Cholangiocarcinoma”。本文使用了LabEx提供的Luminex检测服务。

 

近年来肝内胆管细胞癌（iCCA）作为全球主要癌症问题的现状及相关研究进展。尽管免疫检查点抑制剂（ICIs）和肿瘤微环境（TME）相关的治疗策略在多种实体癌症中取得了突破性进展，但在iCCA中的初步临床结果令人失望，即使ICIs联合化疗在不可切除的iCCA患者中带来了适度的生存益处。为了开发新的治疗策略，亟需深入了解iCCA的发病机制。

 

高通量测序分析扩展了对iCCA分子特征的认识，研究表明KRAS突变是iCCA的主要驱动因素，并且这种突变在炎症亚型中显著富集。炎症能加速肿瘤进展并严重削弱免疫疗法的效果。相反，以前的研究发现白细胞介素-1受体拮抗剂（IL1RN）是一种内源性拮抗剂，通过阻断白细胞介素-1（IL-1）途径来抑制炎症级联反应。然而，KRAS突变如何正面或负面影响iCCA中的炎症和抗肿瘤免疫的分子机制仍不清楚。

 

值得注意的是，越来越多的研究支持替代mRNA剪接（AS）在炎症过程中的关键作用。AS是一个重要的转录后调控过程，通过选择性剪接和重新组装RNA前体来生成多样化的RNA转录本。然而，目前尚未有大规模的iCCA转录组学研究或对KRAS突变相关炎症的深入探索。

 

LabEx提供的Luminex检测服务

除单片段分析外，本实验在 PDTF 细胞培养的上清液中收集了 48 小时后的样品，用于研究细胞因子、趋化因子和细胞毒性介质。这些上清液被立即冷冻并储存在 -80°C。解冻并混合后的上清液使用 LabEX 试剂盒测定其中适当的细胞因子和趋化因子。此外，使用 ELISA 试剂盒（MultiSciences Biotech Co. Ltd.）测定组织上清液中的 CXCL3 和 GZMB 水平，操作按照制造商的说明进行。

  

与接受抗PD-1单药治疗的PDTF相比，接受anakinra加抗PD-1 Ab联合治疗的6名KRAS突变患者的PDTF显示出明显较高的CXCL9、CXCL10和GZMB水平，同时CXCL3等免疫抑制因子也有所下降(图F)。

 

 

重要发现

研究者利用从大量患者中收集的多组学数据，发现 KRAS 突变与肝内胆管癌(iCCA)中与髓系炎症相关的特定 mRNA 替代剪接景观有关。然后，我们发现了一种负反馈机制，在这种机制中，替代剪接导致的白细胞介素1受体拮抗剂(IL1RN)-201/203的上调在KRAS突变的iCCA中具有重要的抗炎作用。在KRAS突变型iCCA小鼠中，IL1RN-201/203的上调和anakinra治疗都能通过改变中性粒细胞的募集和表型来激发显著的抗肿瘤免疫反应。此外，anakinra治疗还能协同增强抗PD-1疗法，激活KRAS突变iCCA小鼠瘤内的GZMB+ CD8+ T细胞。在临床上，我们发现KRAS突变型iCCA患者体内高水平的IL1RN-201/203与抗PD-1免疫疗法的良好反应显著相关。