CD44+ cells enhance pro-tumor stroma in the spatial landscape of colorectal cancer leading edge

BackgroundThe heterogeneity of tumors significantly impacts on colorectal cancer (CRC) progression. However, the influence of this heterogeneity on the spatial architecture of CRC remains largely unknown.MethodsSpatial transcriptomic (ST) analysis of AOM/DSS-induced colorectal cancer (CRC), integrated with single-cell RNA sequencing, generated a comprehensive spatial atlas of CRC. Pseudotime trajectory, stemness evaluation, and cell-cell communication analyses explored how CD44+ tumor cells at the leading edge remodel the tumor microenvironment (TME). In vitro experiments and immunofluorescence staining of clinical samples validated pleiotrophin (PTN) signaling in promoting cancer-associated fibroblasts (CAFs) phenotypic transition and CRC progression.ResultsOur findings revealed a distinctive layered ring-like structure within CRC tissues, where CD44+ tumor cells exhibiting high stemness were positioned at the tumor's leading edge. Inflammatory CAFs (iCAFs)-like, myofibroblastic CAFs (myCAFs)-like cells and pro-tumorigenic neutrophils primarily located at the tumor edge, in proximity to CD44+ tumor cells. CD44+ tumor cells then triggered the phenotypic transition of CAFs into iCAF-like and myCAF-like cells through PTN signaling.ConclusionsOur results provide distinctive insights into how tumor heterogeneity reshapes the TME at the leading edge of tumor, thereby promoting CRC progression.