TI - Matrine inhibits the activity of translation factor eIF4E through dephosphorylation of 4E-BP1 in gastric MKN45 cells . AB - Matrine , from Sophora flavescens , could remarkably inhibit tumor growth and induce apoptosis in various cancer cells in vitro.eIF4E and its inhibitor 4E-BP1 play key roles in regulating mRNA translation and cell proliferation . However , it remained elusive whether matrine inhibited cancer cells growth through attenuating the activity of 4E-BP1 . In this study , we analyzed the effects of matrine on 4E-BP1 and eIF4E in gastric cancer MKN45 cells . Immunoblots showed that matrine inhibited the activity of eIF4E through dephosphorylation of 4E-BP1 in a dose - and time -dependent manner . We found that matrine inactivated Erk1/2 , an upstream regulator of 4E-BP1 and eIF4E , and remarkably reduced the phosphorylation level of 4E-BP1 and eIF4E , whereas 4E-BP1 was little influenced by JNK , p38 or Akt/mTOR . Inactivation of PP2A obviously decreased the phosphorylation of 4E-BP1 in matrine-treated cells . These findings suggested that matrine inhibits the activity of eIF4E by dephosphorylating 4E-BP1 , which partly counts for the growth inhibition in gastric MKN45 cells .