Cellular uptake of Tumor-targeted nanoparticles derived from pullulan acetate conjugate / 医学研究生学报

ABSTRACT

Objective Folate receptors ( FRs) , overexpressed on the surface of a variety of tumor cells , are potential targets for tumor targeting therapy .This study aimed to prepare an FR-mediated drug nanocarrier with folate conjugated pullulan acetate ( FPA) to target chemotherapeutic agents to FR-overexpressed tumor cells and investigate its tumor-suppressing effect in vitro. Methods The cytotoxicity of epirubicin-loaded FPA nanoparticles ( FPA/EPI NP) against HepG2 and Hela cells was evaluated by MTS assay.The HepG2 and Hela cells were divided into five groups to be treated with NPs (NP control), chlorpromazine, chloro-quine, amiloride, and folate, respectively, followed by detection of the fluorescence intensity by flow cytometry . Results FPA/EPI NP was successfully formulated into NPs , with the mean particle size of (268.5 ±12.0) nm, by dialysis with an almost spherical shape . The drug-loading rate and entrapment rate of FPA/EPI NP were (6.45 ±1.04) and (72.45 ±11.50) %, respectively.The survival rates of the HepG2 and Hela cells were both >95%after 24 hours of incubation with FPA NP at 5, 40, 200, 400 and 1000μg/mL and 90.0%after 72 hours.The survival rates of the HepG2 cells treated with 5, 40, 200, 400 and 1000μg/mL FPA/EPI NP for 24 hours were (92.3 ±5.2), (70.4 ±4.6), (50.0 ±4.0), (41.1 ±4.1) and (27.0 ±3.6) %, respectively.Compared with the NP control group, the Hela cells of the chlorpromazine , amiloride and folate groups showed a significantly lower rate of NP uptake (P<0.05), and so did the HepG2 cells pretreated with chlorpromazine or amilo-ride (P<0.05).At 72 hours, the half maximal inhibitory concentrations (IC50) of FPA/EPI NP against HepG2 and Hela cells were 168 and 105μg/mL, respectively . Conclusion Clathrin-mediated endocytosis and macropinocytosis are involved in the internaliza-tion of FPA/EPI NP in HepG2 cells, while clathrin-and FR-mediated endocytosis in that of Hela cells .FPA NP may serve as a new drug carrier for tumor-targeted therapy .