Fisetin targets phosphatidylinositol-3-kinase and induces apoptosis of human B lymphoma Raji cells

Aberrant regulation of phosphatidylinositol-3-kinases (PI3Ks) is known to be involved in the progression of cancers. PI3K-binding flavonoids such as quercetin and myricetin have been shown to inhibit PI3K activity, but the direct targeting of fisetin to PI3K has not been established. Here, we carried out an in silico investigation of fisetin binding to PI3K and determined fisetin's inhibitory activity in enzymatic and cell-based assays. In addition, fisetin induced apoptosis in human Burkitt's lymphoma Raji cells by inhibiting both PI3Ks and mammalian target of rapamycin (mTOR). Our results indicate that fisetin may serve as a natural backbone for the development of novel dual inhibitors of PI3Ks and mTOR for the treatment of cancer.