Axitinib promotes stemness and vasculogenic mimicry in triple-negative breast cancer by disrupting THBS1-CD47 axis-mediated endothelial-tumor cell communication.

Triple-negative breast cancer (TNBC) is an aggressive subtype with limited therapeutic options. Although anti-angiogenic agents like Axitinib are used in cancers, resistance emerges through poorly understood mechanisms involving stemness and vasculogenic mimicry (VM). Here, we investigated the regulatory role of thrombospondin-1 (THBS1), an anti-angiogenic protein, in Axitinib-mediated signaling and its impact on TNBC. The effects of Axitinib on VM, angiogenesis, and stemness in TNBC were investigated through in vivo models and in vitro endothelial-supernatant cultures. Bioinformatics analyses (GSE230643 and CellChat), immunohistochemistry of clinical samples, exosome transfer assays, and xenograft models were employed to explore how Axitinib regulates THBS1-mediated endothelial-TNBC intercellular communication. Further bioinformatics analyses, combined with in vitro and in vivo experimental validations, were performed to elucidate the mechanism of the THBS1-CD47 axis in TNBC. Axitinib treatment increased stemness and promoted VM in TNBC models, despite tumor growth inhibition. Bioinformatics analyses revealed the Axitinib-dependent THBS pathway between endothelial and endothelial-like tumor cells. Axitinib-induced downregulation of THBS1 expression in HUVEC cells promoted stemness and angiogenesis of recipient TNBC cells via exosomes. Mechanistically, endothelial-derived THBS1 promoted CD47 expression in recipient TNBC cells, thereby attenuating the activity of PI3K/Akt and MAPK/ERK signaling pathways, and inhibiting stemness, angiogenesis, and VM. Importantly, Axitinib disrupted this THBS1-CD47 axis by downregulating endothelial-derived THBS1 expression. Axitinib induces the suppression of THBS1 expression in endothelial cells, thereby enhancing stemness and VM in recipient TNBC via disruption of the THBS1-CD47 axis. Restoring THBS1 signaling may represent a promising strategy to overcome Axitinib resistance.