Phospholipid Scramblase 1 Interacts with Midkine and Regulates Hepatic Cancer Cell Proliferation and Migration.

Mounting evidence indicates that nuclear targeting by growth factors plays an indispensable role on their biological activities. Midkine (MK) is a multifunctional growth factor and has been discovered to play important roles in carcinogenesis. MK has been reported to localize to the nucleus and nucleolus of HepG2 cells and is involved in cell proliferation and apoptosis. The interaction was reconfirmed by in vitro pull down and in vivo coimmunoprecipitation (Co-IP), also by the colocalization in the HepG2 cells. The proliferation and migration was determined by MTT and trans-well assay. PLSCR1 was identified as a novel MK-interacting protein. Notably, PLSCR1 interacted with MK in the cell nucleus and regulated hepatic carcinoma cell proliferation and migration. This study suggests that PLSCR1 positively regulates hepatic carcinoma cell proliferation and migration through interacting with MK, thus deepening our understanding on the regulation of midkine during hepatic carcinoma growth and metastasis.