背景:癌症相关成纤维细胞(CAF)在促进肿瘤生长中起关键作用,转移,和免疫逃避。虽然许多研究调查了CAF,关于它们在结直肠癌(CRC)中的临床应用的研究仍然很少。
方法:在本研究中,我们从先前的CRC研究中收集了CAF和正常成纤维细胞(NF)之间的差异表达基因,并利用机器学习分析来区分CRC中两种不同的CAF亚型。为了实现实际应用,基于多变量Cox回归建立了CAF相关基因(CAFGs)评分系统.然后我们进行了功能富集分析,卡普兰-迈耶情节,共有分子亚型(CMS)分类,和肿瘤免疫功能障碍和排除(TIDE)算法来研究CAFGs评分系统与各种生物学机制之间的关系,预后价值,肿瘤微环境,和对免疫检查点阻断(ICB)治疗的反应。此外,单细胞转录组学和蛋白质组学分析已用于验证评分系统相关分子在CAF身份和功能中的重要性。
结果:我们揭示了肿瘤免疫状态和预后的显著差异,不仅是在CAF簇之间,而且在高CAFGs和低CAFGs组中也是如此。具体来说,CAF第2组患者或CAFGs评分较高的患者表现出更高的CAF标志物,并富集了CAF相关的生物学途径,如上皮-间质转化(EMT)和血管生成.此外,CAFGs评分被确定为风险指数,并与不良总生存率(OS)相关,无进展生存期(PFS),无病生存率(DFS),和无复发生存率(RFS)。在晚期患者中观察到较高的CAFGs评分,CMS4,以及淋巴侵入。此外,患者CAFG评分升高表示抑制性肿瘤微环境,其特征是程序性死亡配体1(PD-L1)上调,T细胞功能障碍,排除,和潮汐得分。高CAFGs评分可以区分ICB治疗下反应率低、预后差的患者。值得注意的是,单细胞转录组学和蛋白质组学分析确定了几种与CAF身份和功能相关的分子,例如FSTL1、IGFBP7和FBN1。
结论:我们使用多个CRC队列构建了具有临床意义的稳健CAFGs评分系统。此外,我们确定了几种与CAF身份和功能相关的分子,这些分子可能是CRC患者的潜在干预靶点.
BACKGROUND: Cancer-associated fibroblasts (CAF) play a critical role in promoting tumor growth, metastasis, and immune evasion. While numerous studies have investigated CAF, there remains a paucity of research on their clinical application in colorectal cancer (CRC).
METHODS: In this study, we collected differentially expressed genes between CAF and normal fibroblasts (NF) from previous CRC studies, and utilized machine learning analysis to differentiate two distinct subtypes of CAF in CRC. To enable practical application, a CAF-related genes (CAFGs) scoring system was developed based on multivariate Cox regression. We then conducted functional enrichment analysis, Kaplan-Meier plot, consensus molecular subtypes (CMS) classification, and Tumor Immune Dysfunction and Exclusion (TIDE) algorithm to investigate the relationship between the CAFGs scoring system and various biological mechanisms, prognostic value, tumor microenvironment, and response to immune checkpoint blockade (ICB) therapy. Moreover, single-cell transcriptomics and proteomics analyses have been employed to validate the significance of scoring system-related molecules in the identity and function of CAF.
RESULTS: We unveiled significant distinctions in tumor immune status and prognosis not only between the CAF clusters, but also across high and low CAFGs groups. Specifically, patients in CAF cluster 2 or with high CAFGs scores exhibited higher CAF markers and were enriched for CAF-related biological pathways such as epithelial-mesenchymal transition (EMT) and angiogenesis. In addition, CAFGs score was identified as a risk index and correlated with poor overall survival (OS), progression-free survival (PFS), disease-free survival (DFS), and recurrence-free survival (RFS). High CAFGs scores were observed in patients with advanced stages, CMS4, as well as lymphatic invasion. Furthermore, elevated CAFG scores in patients signified a suppressive tumor microenvironment characterized by the upregulation of programmed death-ligand 1 (PD-L1), T-cell dysfunction, exclusion, and TIDE score. And high CAFGs scores can differentiate patients with lower response rates and poor prognosis under ICB therapy. Notably, single-cell transcriptomics and proteomics analyses identified several molecules related to CAF identity and function, such as FSTL1, IGFBP7, and FBN1.
CONCLUSIONS: We constructed a robust CAFGs score system with clinical significance using multiple CRC cohorts. In addition, we identified several molecules related to CAF identity and function that could be potential intervention targets for CRC patients.