Cytotoxic and proapoptotic activity of ent-16β-17α-dihydroxykaurane on human mammary carcinoma cell line MCF-7

Here we describe the cytotoxic and proapoptotic effect of an ent-kaurane (ent-16beta-17alpha-dihydroxykaurane), compound isolated from Croton malambo, barks, on malignant cell growth. When MCF-7 mammary carcinoma cells were treated with increasing concentrations of the ent-kauranoid, its cytotoxic activity showed an IC50 of 12.5 mug/ml, dose that is 2.66-fold lower than the corresponding value for non-malignant cells. At this growth inhibitory dose, both mRNA and protein levels for Bcl-2 as well as mRNA for hTERT were significantly reduced. The observed preapoptotic activity seemed to be triggered by a mechanism that is not directly affecting NF-kappaB binding ability. The potential use of this plant-derived compound as a cancer chemotherapy agent is discussed. (C) 2004 Elsevier Ireland Ltd. All rights reserved.