Acetone Fraction of the Red Marine Alga Laurencia papillosaReduces the Expression of Bcl-2 Anti-apoptotic Marker andFlotillin-2 Lipid Raft Marker in MCF-7 Breast Cancer Cells

Marine macroalgae have attracted much attention in recent years as a valuable source ofbioactive metabolites. the cytotoxic potential of the laurencia papillosa red alga collected fromthe lebanese coast has been investigated on human breast cancer cells mcf-7. the crude extractof laurencia papillosa (l. papillosa) was fractionated by column chromatography using a seriesof increasingly polar solvents (methylene chloride, acetone and methanol). cytotoxicity of thecrude extract and fractions was determined by mtt assay in mcf-7 cells. apoptosis was detectedby annexin v/propidium iodide assay and by measurement of bcl-2 expression. flotillin-2expression was examined using rt-qpcr and western blot. the crude extract, and the fractionsof ch2cl2 and acetone exhibited a dose-dependent cytotoxic effect on mcf-7 cells. apoptosiswas specifically induced by one of the acetone fractions having the highest cytotoxicity. it hasbeen demonstrated by an increase in late phase apoptotic cell populations, and a decrease in bcl-2 anti-apoptotic marker expression on mrna and protein levels in a dose- and time- dependentmanner. furthermore, this active fraction decreased flotillin-2 expression associated with cancerprogression. our data suggest that l. papillosa is an important source of cytotoxic metabolites.further studies are needed for the chemical characterization of the metabolite associated withobserved biological activities.