Enhancement in anti-proliferative effects of paclitaxel in aortic smooth muscle cells upon co-administration with ceramide using biodegradable polymeric nanoparticles.

PURPOSE: Using a combination of paclitaxel (PTX), and the apoptotic signaling molecule, C6-ceramide (CER), the enhancement in anti-proliferative effect of human aortic smooth muscle cells (SMC) was examined by administering in polymeric nanoparticles.
METHODS: PTX- and CER-loaded poly(ethylene oxide)-modified poly(epsilon caprolactone) (PEO-PCL) nanoparticles were formulated by solvent displacement and characterized. The uptake and intracellular localization of the nanoparticle in SMC was examined using Z-stack fluorescent confocal microscopy. Anti-proliferative and pro-apoptotic effects of SMC were determined upon administration of PTX and CER, either as single agent or in combination, in aqueous solution and in PEO-PCL nanoparticle formulations.
RESULTS: High encapsulation efficiencies (i.e., >95%) of PTX and CER at 10% (w/w) loading were attained in the PEO-PCL nanoparticles of around 270 nm in diameter. Fluorescence confocal analysis showed that nanoparticle delivery did facilitate cellular uptake and internalization. Additionally, combination of PTX and CER delivery in PEO-PCL nanoparticles was significantly more effective in decreasing the proliferation of SMC, probably by enhancing the apoptotic response.
CONCLUSIONS: The results of this study show that combination of PTX and CER when administered in PEO-PCL nanoparticles can significantly augment the anti-proliferative effect in SMC. This strategy may potentially be useful in the treatment of coronary restenosis.