Genistein-induced apoptosis via Akt signaling pathway in anaplastic large-cell lymphoma.

More than half of anaplastic large-cell lymphoma (ALCL) are associated with chromosomal translocation t(2;5)(p23;q35) that leads to the expression of nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) oncoprotein. NPM-ALK activates the antiapoptotic phosphatidylinositol-3 kinase/Akt (PI3K/Akt) signaling pathway, which plays a critical role in cell survival and apoptosis. Inhibition of the PI3K/Akt pathway has been considered as a therapeutic target for cancer where PI3K/Akt activation is a causative factor. Genistein, a natural isoflavonoid found in soy products, has been shown to inhibit cell growth and induce apoptosis in a wide variety of cell lines. Here, we demonstrated that treatment of two t(2;5) ALCL cell lines, SUDHL-1 and Karpas299, with genistein induced apoptosis in a time- and dose-dependent manner. Concurrently, these cells exhibited a decrease in Akt protein levels and subsequent downregulation of Akt activity (Akt phosphorylation). Furthermore, genistein treatment induced mitochondrial membrane potential change, caspase-3 activation and PARP cleavage. From these results, we conclude that inhibition of the Akt signaling pathway and induction of apoptosis by genistein could be used as a new treatment modality for the prevention and/or treatment of t(2;5) ALCL and other hematopoietic malignancies.