Piaopiao Luo, Xiaoqian Ma, Tairan Wang, Yiqing Wang, Xiaoli Liu, Jiang Wang, Yongping Cai, Zhenhua Ren, Hong Zhao, Xiang Nan
Abstract Metastatic osteosarcoma (OS) remains the leading cause of disease-related mortality, yet effective therapies are still lacking. Here, we integrated single-cell RNA sequencing, spatial transcriptomics, and functional assays to investigate signaling dependencies in OS metastasis. Single-cell analysis identified a distinct STMN1⁺ OS cell subpopulation enriched in metastatic samples with enhanced migratory capacity. Clinical correlation analyses showed that elevated STMN1 expression was associated with unfavorable patient outcomes in the TCGA-SARC cohort, although this was not reproduced in the limited TARGET-OS cohort. Cell-cell communication analysis revealed increased interactions between STMN1⁺ OS cells and CAFs, predominantly mediated by IGF signaling. Spatial transcriptomic profiling confirmed the co-localization and coordinated upregulation of IGF1R and STMN1 within IGF1⁺ CAF-rich metastatic niches. Mechanistically, IGF1R signaling upregulated STMN1 expression, while STMN1-high cells exhibited sustained IGF1R signaling activity, suggesting a functional association between STMN1 expression and IGF1R pathway in metastasis. Combined disruption of IGF1R signaling and STMN1 in vitro and in vivo attenuated metastatic phenotypes more potently than single-axis interference, accompanied by cooperative suppression of MAPK and AKT pathway activity. These findings delineate a spatially defined IGF1R-STMN1 signaling axis driving OS metastasis and provide preclinical evidence supporting further evaluation of IGF1R/STMN1 co-targeting in OS.