PTP1B up-regulates EGFR expression by dephosphorylating MYH9 at Y1408 to promote cell migration and invasion in esophageal squamous cell carcinoma.

ABSTRACT

Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers worldwide. Protein tyrosine phosphatase 1B (PTP1B) is a member of protein tyrosine phosphatases (PTPs) family. In our previous work, PTP1B was found to be overexpressed in ESCC tissues and made contributions to the the cell migration and invasion as well as lung metastasis of ESCC. In this study, we explored the underlying molecular mechanisms. PTP1B enhanced cell migration and invasion by promoting epidermal growth factor receptor (EGFR) expression in ESCC, which was relied on phosphatase activity of PTP1B. Using GST-pulldown combined with LC/MS/MS, we found that nonmuscle myosin IIA (MYH9) was a novel substrate of PTP1B in ESCC cells. PTP1B dephosphorylated MYH9 at Y1408, by which PTP1B up-regulated EGFR expression and enhanced cell migration and invasion in ESCC. In conclusion, our study first reported that PTP1B was the positive regulator of EGFR by dephosphorylating MYH9 at Y1408 to promote cell migration and invasion, which revealed the regulatory mechanism of PTP1B-MYH9-EGFR axis in ESCC.