Figure 3.

Enhancement of SFK activities by BQ extract in oral cancer cell Ca9-22. (A) Ca9-22 cells were treated with BQ extract for different periods as indicated and subjected to detection of phospho-Src (pY416) as described in Figure 2B. Phosphorylation at tyrosine 416 was quickly induced within 5 minutes on BQ stimulation. (B) The cellular activity of SFKs treated or untreated with BQ ingredients was detected by in vitro kinase assay. Ca9-22 cells were treated with BQ extract for 30 minutes and then the cell lysates were immunoprecipitated with anti-SFKs antibody (Src2). Cellular Src kinase activities were directly measured on protein A/G agarose beads carrying Src immunocomplex. In the presence of BQ, Src kinases autophosphorylation was significantly increased, leading to increased phosphorylation of the in vitro substrate, enolase (arrows).