Margin-enriched CD4+ central-memory T cells affect macrophages via ANXA1-FPR1 signaling axis to promote tumor progression in intrahepatic cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (iCCA) is the second most prevalent liver cancer with a high mortality and recurrence rate, and remains a poorly understood disease. The tumor margin, as the transition zone between normal tissue and tumor, was not appreciated before. We performed mass cytometry (cytometry by time of flight, CyTOF) on 30 samples from iCCA tumor, paratumor and margin tissue. We found that the number of CD4+ central memory T cells (CD4+ Tcm) increased in the margin zone. Single cell RNA-seq (scRNA-seq) further discovered that CD4+ Tcm cells enriched in the margin zone of iCCA exhibited upregulated Annexin A1 (ANXA1) expression. Fibroblasts recruited CD4+ ANXA1+ Tcm cells via Chemokine (C-C motif) ligand 19 (CCL19)-Chemokine (C-C motif) receptor 7 (CCR7) signaling pathway. The molecular characteristics of CD4+ ANXA1+ Tcm in iCCA were characterized, and the interactions between these T cells and other cells were determined. Patients with enriched CD4+ ANXA1+ Tcm cells in the tumor margin exhibited a worse prognosis. Specifically, CD4+ ANXA1+ Tcm cells could recruit macrophages to the tumor margin and regulate the macrophage polarization via the ANXA1-Formyl Peptide Receptor 1 (FPR1) signaling axis. CD4+ ANXA1+ Tcm cell-activated macrophages could enhance the invasion and proliferation of tumor cells by exerting different cytokines. In conclusion, our study systematically characterized the features and distribution of CD4+ ANXA1+ Tcm cells in the margin zone of iCCA. We investigated the potential mechanisms by which CD4+ ANXA1+ Tcm cells affected tumor progression, and provided novel understanding of the function of these CD4+ Tcm cells in iCCA.