Apoptotic and antiproliferative properties of 3β-hydroxy-Δ5-steroidal congeners from a partially purified column fraction of Dendronephthya gigantea against HL-60 and MCF-7 cancer cells.

Organisms belonging to the genus Dendronephthya are among a group of marine invertebrates that produce a variety of terpenoids with biofunctional properties. Many of these terpenoids have been proven effective as anticancer drugs. Here, we report the antiproliferative effect of 3β-hydroxy-Δ5-steroidal congeners against the proliferation of HL-60 human leukemia cells and MCF-7 human breast cancer cells. The sterol-rich fraction (DGEHF2-1) inhibited the growth of HL-60 and MCF-7 cells with IC50 values of 13.59 ± 1.40 and 29.41 ± 0.87 μg ml-1 respectively. Treatment with DGEHF2-1 caused a dose-dependent increase in apoptotic body formation, DNA damage and the sub-G1 apoptotic cell population. Moreover, DGEHF2-1 downregulated the expression of Bcl-xL while upregulating Bax, caspase-9, and PARP cleavage in both HL-60 and MCF-7 cells. The steroid fraction was found to act via the mitochondria-mediated apoptosis pathway. Identification of the sterols was performed via gas chromatography-tandem mass spectrometry analysis. Studying the mechanism of the anticancer effect caused by these sterol derivatives could lead to the identification of other natural products with anticancer properties.