Anticancer activity of cisplatin-loaded PLGA-mPEG nanoparticles on LNCaP prostate cancer cells

The in vitro anticancer activity of cisplatin-loaded PLGA-mPEG nanoparticles on human prostate cancer LNCaP cells was investigated. The uptake of the PLGA-mPEG nanoparticles by the LNCaP cells was also studied. Blank PLGA-mPEG nanoparticles exhibited low cytotoxicity, which increased with increasing PLGA/PEG ratio in the PLGA-mPEG copolymer used to prepare the nanoparticles, possibly due to the increased cell uptake observed with increasing PLGA/PEG ratio. PLGA-mPEG nanoparticles loaded with cisplatin exerted in vitro anticancer activity against LNCaP cells that was comparable to the activity of free (non-entrapped in nanoparticles) cisplatin. Little differences in the in vitro anticancer activity of the different nanoparticle compositions were found, which may result from the differences observed between the different nanoparticles compositions in the uptake by the LNCaP cells and in the leakage of cisplatin from the nanoparticles during incubation with the cells. Visual evidence of nanoparticles’ uptake by the LNCaP cells was obtained with nanoparticles labeled with PLGA(4165)-PyrBu(274) or dextran-rhodamine B isothiocyanate using fluorescence microscopy. Moreover, in some cases fluorescence around or inside cell nuclei was observed, which, if verified by further studies, would indicate that PLGA-PEG nanoparticles might prove to be useful in site-specific delivery of drugs whose site of pharmacological activity is cell nucleus.