Abstract: Objective To investigate the role and mechanism of ERK1/2 MPAK pathway in regulating proliferation and migration of Eca109 cell line in vitro. Methods We treated Eca109 cells with MAPK（ERK1/2）inhibitor(U0126); cell counting method detected the cell proliferation; Cell morphology was observed under inverted microscope；qRT-PCR detected ERK1/2 mRNA level; Western blot determined the expression of ERK1/2 protein level; MTT and Wound scratch assay detected cell proliferation and migration; qRT-PCR examined miR-21 expression. Results Cell growth was inhibited by U0126 at 20μmol/L doses（p<0.05）, destroyed the normal cell morphology; inactivited ERK1/2 MPAK pathway at protein level（p<0.05）; inhibition of ERK1/2 MPAK pathway repressed cell proliferation and migration of Eca109 cells and downregulated the expression of miR-21（p<0.05）. Conclusion Inhibition of ERK1/2 MPAK pathway weakened cell proliferation and migration of Eca109 cells, one of the most possible mechanism is associated it’s inhibition role on miR-21 expression.

Key words: Key words: ERK1/2, Eca109 cell, proliferation, migration, MicroRNA-21