A kinome-wide high-content siRNA screen identifies MEK5-ERK5 signaling as critical for breast cancer cell EMT and metastasis. Mus musculus

We have employed a high-content microscopy screen in combination with a kinome and phosphatome-wide siRNA library to identify signaling pathways underlying an EMT of murine mammary epithelial cells and breast cancer cells. This screen identified the MEK5-ERK5 axis as a critical player in TGFb-mediated EMT. Suppression of MEK5-ERK5 signaling completely prevented the morphological and molecular changes occurring during a TGFb-induced EMT and, conversely, forced highly metastatic breast cancer cells into a differentiated epithelial state. Inhibition of MEK5-ERK5 signaling also repressed breast cancer cell migration and invasion and substantially reduced lung metastasis without affecting primary tumor growth. The results suggest that the MEK5-ERK5 signaling axis plays an important role in the induction and maintenance of breast cancer cell migration and invasion and thus represents an exploitable target for the pharmacological inhibition of cancer cell metastasis. Overall design: We performed RNA-sequencing of 3 replicates of 2 different cell lines and 2 replicates of another cell line