MICAL‐L2 potentiates Cdc42‐dependent EGFR stability and promotes gastric cancer cell migration

: Enhanced migration potential is a common characteristic of cancer cells induced by mechanisms that are incompletely defined. The present study was designed to investigate relationship of a new discovered cytoskeleton regulator MICAL-L2 and the endogenous epidermal growth factor receptor (EGFR) signalling pathways in gastric cancer cell migration. Increased expression of MICAL-L2 in gastric cancer cells up-regulated EGFR protein level, accompanied by the increase of cell migration, whereas silencing MICAL-L2 down-regulated EGFR and inhibited cell migration. Expression of MICAL-L2 was also shown positively correlated with the activation of HSP27/cytoskeleton and HSP27/β-catenin signalling pathways that provide key mechanisms controlling cell migration. The up-regulating effect of MICAL-L2 on EGFR is mediated through a transcription-independent mechanism that involves inhibiting EGFR protein degradation in lysosome. Further analysis indicated that Cdc42 activation contributed in maintaining the effect of MICAL-L2 on EGFR stability. Furthermore analysis of clinic specimens revealed increased expression of MICAL-L2 in carcinoma tissues and a positive correlation between MICAL-L2 and EGFR expression levels. The above results indicate that MICAL-L2 potentiates gastric cell migration via inhibiting EGFR degradation in lysosome via a Cdc42-dependent manner that leads to the activation of EGFR/HSP27 signalling pathways.