Plumbagin-loaded aptamer-targeted poly d,l-lactic-co-glycolic acid-b-polyethylene glycol nanoparticles for prostate cancer therapy

Plumbagin inhibits the growth, metastasis, and invasion of prostate cancer (PCa). However, its lower bioavailability limits biopharmaceutical properties due to insolubility in water. Prostate-specific membrane antigen (PSMA) aptamer-targeted nanoparticles (NPs) significantly enhanced cytotoxicity in prostate epithelial cells. This study aimed to investigate the effects of plumbagin-loaded prostate-specific membrane antigen (PSMA) aptamer-targeted poly d,l-lactic-co-glycolic acid-b-polyethylene glycol (PLGA-PEG) nanoparticles (NPs) on prostate cancer (PCa) in vitro. PLGA–PEG with a terminal carboxylic acid group (PLGA-PEG-COOH) was synthesized, and plumbagin was loaded on PLGA-PEG-COOH NPs using the nanoprecipitation method and characterized by field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), and laser light scattering. The uptake and distribution of plumbagin-NPs in human PCa LNCaP cells were investigated by fluorescent labeling. Subsequently, PSMA antibody-targeted PLGA-PEG-COOH NPs (targeted NPs) were prepared by covalent binding and characterized by x-ray photoelectron spectroscopy. Furthermore, the anticancer activity of plumbagin-loaded, targeted NPs was compared with that of nontargeted NPs in LNCaP cells in vitro. Plumbagin-NPs (diameter of 189.4 ± 30.6 nm and zeta potential of −17.1 ± 3.7 mV) were optimized based on theoretical drug loading of 5% and a ratio of water:acetone of 3:1. During the first 2 hours, the cumulative release rate of the drug was 66.4 ± 8.56%. Moreover, plumbagin-targeted NPs with nitrogen atoms were prepared. The uptake rate was 90% at 0.5 hours for targeted and nontargeted NPs. The IC(50) of targeted NPs and nontargeted NPs was 32.59 ± 8.03 μM and 39.02 ± 7.64 μM, respectively. Plumbagin-loaded PSMA aptamer-targeted NPs can be used in targeted chemotherapy against PCa.