N,N'-Bis(salicylidene)ethylenediamine iron (Fe(Salen)) is an anti-cancer agent with intrinsic magnetic property. Here, we covalently linked Fe(Salen) to paclitaxel (PTX), a widely used anti-cancer drug, to obtain a magnetized paclitaxel conjugate (M-PTX), which exhibited magnetic characteristics for magnet-guided drug delivery and MRI visualization. M-PTX increased apoptosis and G2/M arrest of cultured human oral cancer cell lines in the same manner as PTX. Furthermore, marked contrast intensity was obtained in magnetic resonance imaging (MRI) of M-PTX. In a mouse oral cancer model, a permanent magnet placed on the body surface adjacent to the tumor resulted in distinct accumulation of M-PTX, and the anti-cancer effect was greater than that of M-PTX without the magnet. We believe that this strategy may improve future cancer chemotherapy by providing conventional anti-cancer drugs with novel functionalities such as magnet-guided drug delivery or MRI-based visualization/quantitation of drug distribution.
Keywords: iron-salen; magnetism; oral cancer; paclitaxel; taxol.