Erythroid differentiation in K562 chronic myelogenous cells induced by crambescidin 800, a pentacyclic guanidine alkaloid.

The differentiation induction of K562 chronic myelogenous leukemia (CML) cells by crambescidin 800, a pentacyclic guanidine alkaloid isolated from a marine sponge, was examined. Crambescidin 800 increased hemoglobin production in K562 cells at concentrations of 0.15-1 microM and arrested the cell cycle of K562 cells at the S-phase. The expression of p21 was detected after 24-h treatment with crambescidin 800, and an increase of the expression was observed after 48-h treatment, but there was no remarkable change in the expression level of p27. This evidence indicates that crambescidin 800 induced the differentiation of K562 cells into erythroblasts accompanied by cell cycle arrest at the S-phase. Furthermore, crambescidin 800 induced a morphological change with neurite outgrowth in Neuro 2A cells at a 0.03-0.1 microM concentration.