FOXF2 deficiency accelerates the visceral metastasis of basal-like breast cancer by unrestrictedly increasing TGF-β and miR-182-5p.

The mesenchymal transcription factor forkhead box F2 (FOXF2) is a critical regulator of embryogenesis and tissue homeostasis. Our previous studies demonstrated that FOXF2 is ectopically expressed in basal-like breast cancer (BLBC) cells and that FOXF2 deficiency promotes the epithelial-mesenchymal transition and aggressiveness of BLBC cells. In this study, we found that FOXF2 controls transforming growth factor-beta (TGF-β)/SMAD signaling pathway activation through transrepression of TGF-β-coding genes in BLBC cells.

FOXF2 reprograms breast cancer cells into bone metastasis seeds.

Bone metastases occur in most advanced breast cancer patients and cause serious skeletal-related complications. The mechanisms by which bone metastasis seeds develop in primary tumors and specifically colonize the bone remain to be elucidated. Here, we show that forkhead box F2 (FOXF2) functions as a master transcription factor for reprogramming cancer cells into an osteomimetic phenotype by pleiotropic transactivation of the BMP4/SMAD1 signaling pathway and bone-related genes that are expressed at early stages of bone differentiation.

Breast cancer cells obtain an osteomimetic feature via epithelial-mesenchymal transition that have undergone BMP2/RUNX2 signaling pathway induction.

Bone is one of the most common organs of breast cancer metastasis. Cancer cells that mimic osteoblasts by expressing bone matrix proteins and factors have a higher likelihood of metastasizing to bone. However, the molecular mechanisms of osteomimicry formation of cancer cells remain undefined.

RUNX2 promotes breast cancer bone metastasis by increasing integrin α5-mediated colonization.

Runt-related transcription factor 2 (RUNX2) is regarded as an important contributor to breast cancer bone metastasis. However, previous studies did not provide direct clinical evidence for a role of RUNX2 in bone-specific metastasis in breast cancer, and the mechanism of RUNX2 in cancer cell recruitment and adhesion to the bone remains unclear. In this study, we showed that RUNX2 expression is positively correlated with the risk of bone-specific metastasis in lymph node-negative breast cancer patients.