Enhanced uptake in 2D- and 3D- lung cancer cell models of redox responsive PEGylated nanoparticles with sensitivity to reducing extra- and intracellular environments

Abstract

In the treatment of lung cancer, there is an urgent need of innovative medicines to optimize pharmacological responses of conventional chemotherapeutics while attenuating side effects. Here, we have exploited some relatively unexplored subtle differences in reduction potential, associated with cancer cell microenvironments in addition to the well-known changes in intracellular redox environment. We report the synthesis and application of novel redox-responsive PLGA (poly(lactic-co-glycolic acid)) -PEG (polyethylene glycol) nanoparticles (RR-NPs) programmed to change surface properties when entering tumor microenvironments, thus enhancing cell internalization of the particles and their drug cargo. The new co-polymers, in which PEG and PLGA were linked by 'anchiomeric effector' dithiylethanoate esters, were synthesized by a combination of ring-opening polymerization and Michael addition reactions and employed to prepare NPs. Non redox-responsive nanoparticles (nRR-NPs) based on related PLGA-PEG copolymers were also prepared as comparators. Spherical NPs of around 120 nm diameter with a low polydispersity index and negative zeta potential as well as good drug loading of docetaxel were obtained. The NPs showed prolonged stability in relevant simulated biological fluids and a high ability to penetrate an artificial mucus layer due to the presence of the external PEG coating. Stability, FRET and drug release studies in conditions simulating intracellular reductive environments demonstrated a fast disassembly of the external shell of the NPs, thus triggering on-demand drug release. FACS measurements and confocal microscopy showed increased and faster uptake of RR-NPs in both 2D- and 3D- cell culture models of lung cancer compared to nRR-NPs. In particular, the 'designed-in' reductive instability of RR-NPs in conditioned cell media, the fast PEG release in the extracellular compartment, as well as a diminution of uptake rate in control experiments where extracellular thiols were neutralized, suggested a partial extracellular release of the PEG fringe that promoted rapid internalization of the residual NPs into cells. Taken together, these results provide further evidence of the effectiveness of PEGylated reducible nanocarriers to permeate mucus layer barriers, and establish a new means to enhance cancer cell uptake of drug carriers by extra-and intra-cellular cleavage of protein- and cell-shielding hydrophilic blocks.

Effects of Polymer 3D Architecture, Size, and Chemistry on Biological Transport and Drug Delivery In Vitro and in Orthotopic Triple Negative Breast Cancer Models

“…[73] Each material was incubated in GSH in PBS at 37°C and measured at 1, 24, and 48 h to assess any changes in size. [74] The linear, star and hyperbranched structures showed a decrease in diameter over time as expected (Figure 1D,E) due to disassembly into their smaller linear fragments, however there was no significant change in the diameter of the core-crosslinked micelles during the experiment. As the micelles were core-crosslinked in situ during the polymerization process, it is likely that the disulfides are embedded deep within the hydrophobic core and thus are not very accessible.…”

Hepato(Geno)Toxicity Assessment of Nanoparticles in a HepG2 Liver Spheroid Model

“…However, when exposing the already formed spheroids for 24 h, NPs were seen only to a depth of 20 µm [26]. Cell types, cell densities, physicochemical characteristics of the NPs (including size distribution) and ion release may influence the penetration inside the spheroid [73][74][75][76][77].…”

Hypoxia-activated prodrugs and redox-responsive nanocarriers

“…The cell uptake efficiency of redox-responsive NPs on 3D cell culture models of lung cancer was higher than that of nonredox-responsive NPs, and the extracellular release of PEG fringe could promote the internalization of NPs. 102 Redoxresponsive PTX-loaded PEG micelles were modified with ABD035, a peptide with albumin-binding domain, targeting overexpressing albumin-binding proteins such as secreted protein acidic and rich in cysteine (SPARC) and gp60. The cellular internalization results indicated that the accelerated transport rate was due to SPARC-and caveolin-1-mediated pathways and therefore improved therapeutic effects on representative drug resistance model: triple-negative breast cancer by increasing cellular internalization as well as drug distribution.…”