Effects of paclitaxel delivery by carbon nanotubes on prostate cancer cells and monocytes

Carbon nanotubes (NT) have properties that make them useful in the biomedical field, for instance for controlled drug delivery. Indeed, NT can be loaded with antitumor drugs, such as paclitaxel (PTX), in order to guide drug... [ view full abstract ]

Carbon nanotubes (NT) have properties that make them useful in the biomedical field, for instance for controlled drug delivery. Indeed, NT can be loaded with antitumor drugs, such as paclitaxel (PTX), in order to guide drug release within the tumor cells. Considering the high-energy metabolism of tumor cells, we revested PTX-loaded NT with glucose molecules (GLY) in order to test their toxicity on both human prostate cancer cells and monocytes of health donors. First, we increased the polydispersity of NT in aqueous solution synthesizing them with polyethyleneimine (PEI) and polyethyleneimine combined with glucose (PEI-GLY). Analysis by Fourier transform infrared spectroscopy (FTIR – Nicoletspectrometer Nexus 670) confirmed the incorporation of polymer on NT walls. Transmission electron microscopy was used to study NT structure and morphological changes induced by incorporated material. The amount of PTX incorporated by NT was estimated by UV/visible spectroscopy. Cytotoxic activity on prostate cancer cells (LNCaP) was confirmed by flow cytometry after 48h incubation with nanoparticles. Analysis of cell viability was based on Annexin V- (apoptosis) and 7AAD- (cell death) labeling and analysis by flow cytometry in five experimental conditions: a) NT; b) NT-PTX; c) NT-GLY; d) NT-GLY-PTX and e) equivalent concentration of pure PTX. NT-PTX showed as high cytotoxic activity as pure PTX, that was significantly higher than NT alone or NT-GLY. The most interesting finding was that cytotoxic effects of NT-GLY-PTX had slightly higher than pure PTX and NT-PTX, indicating that glucose favors the interaction of particles with tumor cells (Fig.1). We also analyzed the effect of NT on the viability and phenotype of monocytes of health donors exposed to NT, NT-PTX, NT-GLY and NT-GLY-PX. Our results show that expression of CD80, CD86, HLA-DR and CD83 was not hindered by exposition to nanotubes (any of preparations), while all formulations increased the expression of PD-L1 molecules on monocytes. These results indicate that glucose enhance the drug-carrier property of NT, and has low toxic effect on normal monocytes.