Firstly, the effects of various chemoattractant profiles were investigated. The FBS-containing RPMI medium in the lower chamber enhanced the migration of MDA-MB-231, denoted as untreated cells (figs. ). Nevertheless, the absence of FBS showed significant inhibitory effects for cell migration. In contrast, the addition of either EGF or DETA-NO to the lower chamber enhanced the cell migration with different levels. However, the presence of each of the tested compounds in the FBS-containing medium negated the effects of DETA-NO and inhibited the cell migration with different efficiencies. For instance, both hemin and its conjugates caused significant inhibition for the • NO-induced migration (figs. ).