A simple method for preparing 5-fluorouracil surface-
functionalized selenium nanoparticles (5FU-SeNPs) with enhanced anticancer activity has been demonstrated in the present study. Spherical SeNPs were capped with 5FU through formation of Se鈥揙 and Se鈥揘 bonds and physical adsorption, leading to the stable structure of the conjugates. 5FU surface decoration significantly enhanced the cellular uptake of SeNPs through endocytosis. A panel of five human cancer cell lines was shown to be susceptible to 5FU-SeNPs, with IC
50 values ranging from 6.2 to 14.4 渭M. Despite this potency, 5FU-SeNP possesses great selectivity between cancer and normal cells. Induction of apoptosis in A375 human melanoma cells by 5FU-SeNPs was evidenced by accumulation of sub-G1 cell population, DNA fragmentation, and nuclear condensation. The contribution of the intrinsic apoptotic pathway to the cell apoptosis was confirmed by activation of caspase-9 and depletion of mitochondrial membrane potential. Pretreatment of cells with a general caspase inhibitor z-VAD-fmk significantly prevented 5FU-SeNP-induced apoptosis, indicating that 5FU-SeNP induced caspase-dependent apoptosis in A375 cells. Furthermore, 5FU-SeNP-induced apoptosis was found dependent on ROS generation. Our results suggest that the strategy to use SeNPs as a carrier of 5FU could be a highly efficient way to achieve anticancer synergism. 5FU-SeNPs may be a candidate for
further evaluation as a chemopreventive and chemotherapeutic agent for human cancers, especially melanoma.
Keywords:
selenium nanoparticles; 5-fluorouracil; cellular uptake; synergistic effects; apoptosis