Thyrsiferyl 23-acetate and its derivatives induce apoptosis in various T- and B-leukemia cells.

Thyrsiferyl 23-acetate (TF-23A), a cytotoxic compound from marine red alga, induced a rapid cell death in various leukemic T- and B-cell lines. During incubation of Jurkat cells with TF-23A, condensation and fragmentation of nuclei occurred and clusters composed of uneven small cellular particles were formed. Concentration- and time-dependent DNA fragmentation was also induced by the incubation of the cells with TF-23A. These results demonstrate that the TF-23A-induced cell death follows a typical apoptotic process. The TF-23A-induced apoptosis was prevented by fetal calf serum and insulin, but not by EGF or PDGF. TF-23A and its several analogous compounds showed apoptosis-inducing activity. However, only TF-23A out of these compounds showed an inhibitory activity for protein phosphatase 2A, PP2A. These results strongly suggest that a structure of TF-23A involved in induction of apoptosis is different from that involved in the PP2A inhibition.