[Studies of effect of prosaposin on cell proliferation, cell apoptosis and its possible molecular mechanism].

pcDNA3.1 in NIH3T3 and Psap-Myc in NIH3T3 cell strains were used as cell models in order to study the effect of prosaposin on cell proliferation, cell apoptosis and its possible molecular mechanism. MTT assay and Annexin V/PI apoptosis kit were used to detect the effect of prosaposin on cell proliferation and cell apoptosis induced by se-rum-starvation stress, respectively. Western blotting was conducted to detect the phosphorylative level of PI3K/Akt pathway, and real-time PCR was carried out to explore the expression of the genes regulated by PI3K/Akt pathway. Prosaposin pro-tein was proved to activate the PI3K/Akt signal pathway, upregulate the phosphorylative activity of Akt at Serine 473, downregulate the expression of P27(Kip1) gene, upregulate the expression of Cyclin D1 gene and then promote the G1/S tran-sition, and upregulate the expression of survival genes cIAP1 and cIAP2 and then prevent cell apoptosis. These findings suggest that the growth promotion and anti-apoptotic activity of prosaposin may be partly through the PI3K/Akt signal pathway and its downstream targeted genes.