A fraction isolated from the gorgonian Rumphella aggregata (Plexauridae) wa
s studied vitro on asynchronous cells of a human non-small-cell-bronchopulm
onary-carcinoma line (NSCLC- N6). Cell growth appeared to be inhibited in t
he GI phase of the cell cycle, and kinetic studies in pretreated cells show
ed that this growth arrest was irreversible. These events seem to show a te
rminal maturation induced by this new product.