Li Lu, You Liting, Bi Zhenfei, Zhang Ziqi, Ying Binwu, Luo Min, Wei Xiawei
Laboratory of Aging Research and Cancer Drug Target, Department of Biotherapy and Cancer Center, State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan Province 610041, P. R. China.
Clinical Trial Center, West China Hospital, Sichuan University, Chengdu, Sichuan Province 610041, P. R. China.
Theranostics. 2025 Jul 25;15(16):8473-8487. doi: 10.7150/thno.112009. eCollection 2025.
Chitosan, a natural polysaccharide with known immunostimulatory potential, has shown promise in cancer therapy. However, its direct role in modulating antitumor immunity and the underlying mechanisms remain unclear. This study aimed to explore how unmodified chitosan influences tumor progression and immune responses through innate immune signaling pathways. Murine tumor models (CT26, B16-F10) were used to evaluate the antitumor effects of chitosan in vivo. Flow cytometry and histological analyses assessed changes in immune cell infiltration. Primary macrophages and gene knockout models were used to investigate the molecular mechanisms, including inflammasome activation, mitochondrial function, and hexokinase 2 (HK2) location, via ELISA, western blotting, mitochondrial assays. Chitosan treatment suppressed tumor growth and metastasis, while promoting infiltration of neutrophils, monocytes, and activated T cells in the tumor microenvironment. Mechanistically, chitosan and its bioactive degradation product, N-acetylglucosamine (NAG), induced the dissociation of HK2 from mitochondria, triggering mitochondrial dysfunction, ROS overproduction, and mtDNA release. These signals jointly activated both the NLRP3 inflammasome and the cGAS-STING pathway. The antitumor effect of chitosan was attenuated in and mice, confirming the essential roles of both pathways. Chitosan orchestrates dual activation of NLRP3 and cGAS-STING signaling via HK2 dissociation and mitochondrial dysfunction, reprogramming the tumor immune microenvironment and enhancing antitumor immunity. These findings support chitosan's potential as a multifunctional immunoadjuvant for improving immunotherapy in resistant cancers.
壳聚糖是一种具有已知免疫刺激潜力的天然多糖，在癌症治疗中显示出前景。然而，其在调节抗肿瘤免疫中的直接作用及潜在机制仍不清楚。本研究旨在探讨未修饰的壳聚糖如何通过天然免疫信号通路影响肿瘤进展和免疫反应。使用小鼠肿瘤模型（CT26、B16-F10）评估壳聚糖在体内的抗肿瘤作用。通过流式细胞术和组织学分析评估免疫细胞浸润的变化。使用原代巨噬细胞和基因敲除模型，通过酶联免疫吸附测定（ELISA）、蛋白质印迹法、线粒体分析等方法研究分子机制，包括炎性小体激活、线粒体功能和己糖激酶2（HK2）定位。壳聚糖治疗抑制了肿瘤生长和转移，同时促进了肿瘤微环境中中性粒细胞、单核细胞和活化T细胞的浸润。从机制上讲，壳聚糖及其生物活性降解产物N-乙酰葡糖胺（NAG）诱导HK2从线粒体解离，触发线粒体功能障碍、活性氧（ROS）过度产生和线粒体DNA（mtDNA）释放。这些信号共同激活了NLRP3炎性小体和cGAS-STING通路。壳聚糖在Nlrp3−/−和Sting−/−小鼠中的抗肿瘤作用减弱，证实了这两条通路的重要作用。壳聚糖通过HK2解离和线粒体功能障碍协调NLRP3和cGAS-STING信号的双重激活，重新编程肿瘤免疫微环境并增强抗肿瘤免疫力。这些发现支持壳聚糖作为多功能免疫佐剂在改善难治性癌症免疫治疗方面的潜力。
