Abstract Abnormal biosyntheses of steroid hormones and dysregulation of steroid hormone receptors contribute to breast cancer metastasis but the mechanisms of that are poorly understand. Here we report a stress hormone producing enzyme, Hydroxysteroid (11-Beta) Dehydrogenase 1 (HSD11β1) promotes breast cancer metastasis. HSD11β1 was ectopically expressed in seventy-one percent of triple-negative breast tumors and correlated with shorter overall survival. HSD11β1 significantly promoted breast cancer metastasis through induction of epithelial-to-mesenchymal transition (EMT); conversely, pharmacologic and genetic inhibition of HSD11β1 suppressed metastatic progression of breast cancer cells. Moreover, 11-hydroxyprogesterone (11-OHP) whom HSD11β1 produced in breast cancer cells, conferred metastatic properties on non-metastatic breast cancer cells through induction of EMT. We identified Peroxisome Proliferator-activated Receptor Alpha (PPAR-α) as essential for both HSD11β1 and 11OHP-driven EMT. Knockdown of PPAR-α induced MET on HSD11β1-expressing breast cancer cells. Taken together, HSD11β1 promotes breast cancer metastasis and would be a novel target for suppressing breast cancer metastasis.

HSD11β1 promotes EMT-mediated breast cancer metastasis