Targeted nanoparticle-aptamer bioconjugates for cancer chemotherapy <i>in vivo</i>

TLDR

Targeted uptake of therapeutic nanoparticles in a cell-, tissue-, or disease-specific manner represents a potentially powerful technology. The study aims to develop docetaxel‑loaded PLGA‑PEG nanoparticles functionalized with PSMA‑binding A10 RNA aptamers for prostate cancer therapy. The authors encapsulated docetaxel in PLGA‑PEG nanoparticles and surface‑functionalized them with A10 aptamers that recognize the extracellular domain of prostate‑specific membrane antigen on prostate cancer cells. The PSMA‑targeted docetaxel nanoparticles showed markedly higher in vitro cytotoxicity than non‑targeted particles, reduced body‑weight loss in mice, achieved complete tumor regression in 5 of 7 xenografts, and conferred 100 % survival at 109 days versus 57 % for non‑targeted particles and 14 % for free docetaxel, indicating strong therapeutic benefit.

Abstract

Targeted uptake of therapeutic nanoparticles in a cell-, tissue-, or disease-specific manner represents a potentially powerful technology. Using prostate cancer as a model, we report docetaxel (Dtxl)-encapsulated nanoparticles formulated with biocompatible and biodegradable poly( d , l -lactic- co -glycolic acid)- block -poly(ethylene glycol) (PLGA- b -PEG) copolymer and surface functionalized with the A10 2′-fluoropyrimidine RNA aptamers that recognize the extracellular domain of the prostate-specific membrane antigen (PSMA), a well characterized antigen expressed on the surface of prostate cancer cells. These Dtxl-encapsulated nanoparticle-aptamer bioconjugates (Dtxl-NP-Apt) bind to the PSMA protein expressed on the surface of LNCaP prostate epithelial cells and get taken up by these cells resulting in significantly enhanced in vitro cellular toxicity as compared with nontargeted nanoparticles that lack the PSMA aptamer (Dtxl-NP) ( P &lt; 0.0004). The Dtxl-NP-Apt bioconjugates also exhibit remarkable efficacy and reduced toxicity as measured by mean body weight loss (BWL) in vivo [body weight loss of 7.7 ± 4% vs. 18 ± 5% for Dtxl-NP-Apt vs. Dtxl-NP at nadir, respectively (mean ± SD); n = 7]. After a single intratumoral injection of Dtxl-NP-Apt bioconjugates, complete tumor reduction was observed in five of seven LNCaP xenograft nude mice (initial tumor volume of ≈300 mm 3 ), and 100% of these animals survived our 109-day study. In contrast, two of seven mice in the Dtxl-NP group had complete tumor reduction with 109-day survivability of only 57%. Dtxl alone had a survivability of only 14%. Saline and nanoparticles without drug were similarly nonefficacious. This report demonstrates the potential utility of nanoparticle-aptamer bioconjugates for a therapeutic application.