Fig. 8

A low metastatic subclone promotes lung metastasis of highly metastatic subclone via exosomal Wnt7a. Tumors comprise multiple subclones with different features. In the TME of 4T1 BC, LM.4T1 cells secrete exosomes containing Wnt7a, leading to the activation of the PI3K/Akt/mTOR signaling pathway and subsequent increases in the stemness and invasion in HM.4T1 cells. LM.4T1-derived Wnt7a also increases angiogenesis, contributing to the increased metastasis by HM.4T1 cells