Myosin Light-Chain Kinase Inhibitors Attenuate Nanoparticles-Induced Autophagy and Cytotoxicity by Suppression Endocytosis

Myosin light-chain kinase (MLCK) is a widely known kinase that controls the contraction of muscle cells. Whether MLCK is involved in the endocytosis of nanoparticles (NPs) has not been reported yet. NPs attract interest in many fields; most of them can induce autophagy and cytotoxicity after entering cells via endocytosis. In this study, we found that MLCK inhibitors, ML-7 and ML-9, abolished the endocytosis of silver NPs and yttrium oxide NPs in HeLa cells, and subsequently attenuated the autophagy induction and cytotoxicity caused by the NPs treatment. This is the first report that MLCK inhibitors acted as an endocytosis inhibitor and abolished the cell entry of NPs, which provided a new method for inhibiting the endocytosis of NPs.