RESUMO
Many studies have so far confirmed the efficiency of phytochemicals in the treatment of prostate cancer.Eupatorin,a flavonoid with a wide range of phytomedical activities,suppresses proliferation of and in-duces apoptosis of multiple cancer cell lines.However,low solubility,poor bioavailability,and rapid degradation limit its efficacy.The aim of our study was to evaluate whether the use of mPEG-b-poly(lactic-co-glycolic)acid(PLGA)coated iron oxide nanoparticles as a carrier could enhance the therapeutic efficacy of eupatorin in DU-145 and LNcaP human prostate cancer cell lines.Nanoparticles were prepared by the co-precipitation method and were fully characterized for morphology,surface charge,particle size,drug loading,encapsulation efficiency and in vitro drug-release profile.The inhibitory effect of nanoparticles on cell viability was evaluated by MTT test.Apoptosis was then determined by Hoechest staining,cell cycle analysis,NO production,annexin/propidium iodide(PI)assay,and Western blotting.The results indicated that eupatorin was successfully entrapped in Fe3O4@mPEG-b-PLGA nanoparticles with an efficacy of(90.99 ± 2.1)％.The nanoparticle's size was around(58.5 ± 4)nm with a negative surface charge[(-34.16 ± 1.3)mV].In vitro release investigation showed a 30％initial burst release of eupatorin in 24 h,followed by sustained release over 200 h.The MTT assay indicated that eupatorin-loaded Fe3O4@mPEG-b-PLGA nanoparticles exhibited a significant decrease in the growth rate of DU-145 and LNcaP cells and their IC50 concentrations were 100 μM and 75 μM,respectively.Next,apoptosis was confirmed by nuclear condensation,enhancement of cell population in the sub-G1 phase and increased NO level.Annexin/PI analysis demonstrated that eupatorin-loaded Fe3O4@mPEG-b-PLGA nanoparticles could increase apoptosis and decrease necrosis frequency.Finally,Western blotting analysis confirmed these results and showed that Bax/Bcl-2 ratio and the cleaved caspase-3 level were up-regulated by the designing nanoparticles.Encapsulation of eupatorin in Fe3O4@mPEG-b-PLGA nanoparticles increased its anticancer effects in prostate cancer cell lines as compared to free eupatorin.Based on these results,this formulation can provide a sustained eupatorin-delivery system for cancer treatment with the drug remaining active at a significantly lower dose,making it a suitable candidate for pharmacological uses.