Breast Cancer Subtype-Specific Organotropism Is Dictated by FOXF2-Regulated Metastatic Dormancy and Recovery

Breast cancer subtypes display different metastatic organotropism. Identification of the mechanisms underlying subtype-specific organotropism could help uncover potential approaches to prevent and treat metastasis. In this study, we found that forkhead box F2 (FOXF2) promoted the seeding and proliferative recovery from dormancy of luminal breast cancer (LumBC) and basal-like breast cancer (BLBC) cells in the bone by activating the NF-κB and BMP signaling pathways. FOXF2 promoted LumBC cell seeding but not proliferative recovery in the lung by activating the BMP signaling pathway. Conversely, FOXF2 suppressed the seeding and proliferative recovery of BLBC cells in the lung by repressing the TGFβ signaling pathway. FOXF2 directly upregulated RelA/p65 transcription and expression in LumBC and BLBC cells by binding to the RELA proximal promoter region and RelA/p65 bound to the FOXF2 proximal promoter region to upregulate expression, forming a positive feedback loop. Targeting the NF-κB pathway efficiently prevented the metastasis of FOXF2-overexpressing breast cancer cells to the bone, whereas inhibiting TGFβ signaling blocked the metastasis of BLBC with low FOXF2 expression to the lung. These findings uncover critical mechanisms of breast cancer subtype-specific organotropism and provide insights into precision assessment and treatment strategies. Significance: FOXF2 regulates signaling pathways in a subtype-specific manner to coordinate the fate of disseminated breast cancer cells in distant organs, suggesting that FOXF2 functions could be harnessed to prevent organ-specific metastasis. See related commentary by Bado, p. 639.