FSBP suppresses tumor cell migration by inhibiting the JNK pathway.

The main cause of high mortality in cancer patients is tumor metastasis. Exploring the underlying mechanism of tumor metastasis is of great significance for clinical treatments. Here, we identify the transcription factor Apt/FSBP is a suppressor for tumor metastasis. In Drosophila wing disc, knockdown of apt is able to trigger cell migration, whereas overexpression of apt hampers scrib-RNAi-induced tumor cell migration. Further studies show that loss of apt promotes cell migration through activating the JNK pathway. To investigate the role of FSBP, the homolog of Apt in mammals, we construct Fsbp liver-specific knockout mice. Knockout of Fsbp in liver does not cause any detectable physiological defects, but predisposes to tumorigenesis on DEN and CCl4 treatment. In addition, loss of Fsbp accelerates tumor metastasis from liver to diaphragm. Taken together, this study uncovers FSBP is a novel tumor suppressor, and provides it as a considerable drug target for tumor treatment.