肠道菌群及其代谢产物在结直肠癌免疫治疗中的研究进展

Progress of Gut Flora and Its Metabolites in the Immunotherapy of Colorectal Cancer

摘要: 肠道菌群是一种居住在胃肠道管腔的微生物群落，包括细菌性生物群落(即肠道细菌)和非细菌性生物群落(如真菌、病毒、螺旋体等)，在调节宿主生理和肠道稳态方面具有不可忽视的作用。肠道菌群参与饮食消化，能够通过释放多种代谢产物来与宿主的肠道上皮和免疫细胞相互作用，从而调节结直肠癌(CRC)的发展。越来越多的研究报道了代谢物与CRC发展之间的相关性，因此应该进行系统地总结。由于早期筛查的普及率低，中老年人规律接受肠镜随访的比例低，大多数结直肠癌患者因出现典型症状而就诊时肿瘤已处于进展期。尽管有了现代治疗方法，但结直肠癌的治疗效果仍然不尽人意，死亡率居高不下。因此，迫切需要识别危险因素和生物标志物，提高对这种癌症的治疗效果。本文重点探讨了肠道微生物群及其代谢产物在结直肠癌的发生发展和如何作为免疫治疗的辅助剂来提高药物的疗效和安全性。

Abstract: Gut flora is a microbial community residing in the lumen of the gastrointestinal tract, including bacterial biota (i.e., enterobacteria) and non-bacterial biota (e.g., fungi, viruses, spirochetes, etc.), which has a non-negligible role in regulating host physiology and intestinal homeostasis. Gut flora are involved in dietary digestion and are able to regulate colorectal cancer (CRC) development by releasing a variety of metabolites that interact with the host’s intestinal epithelium and immune cells. An increasing number of studies have reported the correlation between metabolites and CRC development, and should therefore be systematically summarised. Due to the low prevalence of early screening and the low percentage of middle-aged and elderly people who regularly undergo follow-up colonoscopy, most colorectal cancer patients present to the clinic with typical symptoms when their tumours are already in a progressive stage. Despite the availability of modern treatments, the outcome of colorectal cancer remains unsatisfactory and the mortality rate remains high. Therefore, there is an urgent need to identify risk factors and biomarkers to improve treatment outcomes for this cancer. This paper focuses on the gut microbiota and its metabolites in the development of colorectal cancer and how they can be used as adjuvants to immunotherapy to improve drug efficacy and safety.