Alpha-fetoprotein up-regulated the expression of c-Src in hepatoma cells is PTEN/AKT signaling pathway dependent or independent.

Abstract

e21061 Background: The evidences indicated that alpha-fetoprotein (AFP) harbors a function to promote the proliferation of hepatoma cells, but the role of AFP regulates the expression of oncogenes was unclear. The present study explored the effects of AFP on the expression of c-Src in human hepatoma cells. Methods: Human hepatoma cells line, Bel 7402 and HepG2 (AFP-producing), or HLE (non-AFP-producing) were selected for performing the investigation; Constructed siRNA vector to knockdown the expression of AFP or PTEN, and full length cDNA of AFP gene was inserted into pcDNA3.1 vector (named pcDNA3.1-afp) for the expression of AFP; The expression of Src and AKT (phosphorylation of AKT Ser473) were measured by Western blot; Interaction of AFP with PTEN was analyzed by co- immunoprecipitation (Co-IP); Chromatin immunoprecipitation (ChIP) were applied to investigate the interaction of AFP with Src gene promoter. Results: Co-IP indicated that AFP has a property to interact with PTEN in Bel 7402 or HepG2 cells, and the same effect also showed when HLE cells were transfected with pcDNA3.1-afp; The expression of AKT Ser473 phosphorylated and Src were decreased concomitant with blocked the expression of AFP by siRNA-AFP in Bel 7402 or HepG2 cells, but HLE cells was transfected with pcDNA3.1-afp could enhance the expression of AKT Ser473 phosphorylated and Src, while co-treatment with Ly294002, the expression of Src was partial inhibited. Cotransfected siRNA-PTEN with pcDNA3.1-afp into HLE cells revealed the expression of Src was promoted, and Ly294002 could also partial repress this effect. ChIP analyzed indicated that AFP was able to interact with promoter of src. Conclusions: AFP has a characteristic to stimulate the expression of Src in hepatoma cells, these were first evidences to show that AFP up-regulated the expression of Src through activating the transducation of PTEN/AKT signaling pathway or directed binding to the promoter of src. No significant financial relationships to disclose.