Secondary metabolites from marine cyanobacteria and algae inhibit LFA-1/ICAM-1 mediated cell adhesion

An assay for inhibitors of LFA-1/ICAM-1 mediated cell-cell adhesion has been employed to identify new pharmacologically active compounds from marine cyanobacteria and algae. From a panel of sixty unusual marine natural products, seventeen compounds inhibited LFA-1/ICAM-1-based cell aggregation without showing significant cytotoxicity in the primary assay. Six compounds inhibited the cell-cell adhesion of HL-60 cells to CHO-ICAM-1 cells. The unusual oxylipin Cymathere aldehyde methyl ester (IC (50) 3.5 microM), cyanobacterial lipopeptides microcolins B (IC (50) 0.15 microM) and D (IC (50) 0.9 microM), bromophenol avrainvilleol (IC (50) 2.2 microM), sesquiterpene cymopol (IC (50) 2.7 microM), and cryptophyte derived compound styrylchromone hormothamnione diacetate (IC (50) 1.5 microM) significantly inhibited LFA-1/ICAM-1 mediated cell adhesion. The pharmacological activity and structure-activity relationships of selected marine algal metabolites are described. Abbreviations. LFA-1:Lymphocyte function-associated molecule-1 ICAM-1:Intercellular cell adhesion molecule-1 PMA:Phorbol 12-myristate 13-acetate HL-60:Promyelocytic human leukemia-60 CHO:Chinese hamster ovary