CD8+MTs+ Effector T Cells from Enlarged Tumor-Draining Lymph Nodes Drive Enhanced Tumor Immunogenicity and Improved Prognosis in Colorectal Cancer Patients

Tumor-draining lymph nodes (TDLNs) play a crucial role in anti-tumor immunity. However, the heterogeneity of TDLNs significantly impacts their immune function. We employed single-cell RNA sequencing to dissect the immune landscape of TDLNs of colorectal cancer (CRC), revealing that enlarged non-metastatic TDLNs (L-TDLNs) are enriched with CD8+ effector T cells (Teff) exhibiting a distinct metallothionein (MT)-positive signature. These CD8+MTs+ Teff cells, characterized by heightened cytotoxicity and a stress-adapted phenotype, are critical mediators of anti-tumor immunity. Our data indicate that these cells migrate from L-TDLNs to tumor sites, enhancing tumor immunogenicity. Moreover, CRC patients with a high level of CD8+MTs+ Teff in tumor site showed a significant survival advantage, particularly when treated with adjuvant chemotherapy. These findings underscore the importance of L-TDLNs in shaping effective antitumor immune responses in CRC, suggesting that the CD8+MTs+ Teff cell population may serve as a novel prognostic biomarker and therapeutic target. Our study provides a comprehensive framework for understanding the cellular dynamics within TDLNs and their impact on CRC progression and treatment response. Overall design: To elucidate the ecosystem of primary CRC and especially the different TDLNs, we first used droplet-based scRNA-seq to profile the transcriptomes of 57,427 cells from 8 fresh CRC samples, including 2 CRC, 2 metastatic TDLNs (M-TDLNs), 4 non-metastatic TDLNs (N-TDLNs) tissues.