Targeting Oxidative Stress Pathways in Cancer Cells Using Smart Nanoscale Compounds

Background: Tumor cells have a very delicate redox balance that not only allows them to multiply but also makes them vulnerable to additional oxidative agents. The development of smart nanoscale compounds that can deliberately extinguish this balance is a very appealing therapeutic approach.

Objectives: The objective of this study was to design and in vitro evaluate the multifunctional and stimulus-responsive nanoparticles that were engineered to move tumor redox networks towards lethal oxidative stress. The lead design, "NP-Quantum," was developed to do so while controlling the antioxidant responses to a minimum.

Methods: We created a polymeric nanocarrier with a β-esterase-cleavable shell and a quinone-based prodrug core. The platform was physicochemically characterized and its biological activity was assessed in vitro using human cancer cell lines (MCF-7, A549, HeLa). Evaluations included cytotoxicity, intracellular reactive oxygen species (ROS) generation, glutathione (GSH) depletion, and induction of apoptosis.

Results: The nanoparticles produced were identical in size and were less than 120 nm in size. NP-Quantum exhibited a quick, dependent on the dose rise of ROS (mean peak increase ≈70% at 10 μM, 24 hr), considerable GSH reduction (~45–65%), and NRF2 pathway inhibition. Consequently, there was an increase in caspase-3 activity and cell viability was reduced by about 50%. A very high level of association (Pearson r ≈ 0.88) was found between the increase of ROS and apoptosis.

Conclusion: The smart compounds at the nanoscale which couple the enzymatic activation and the redox-sensitive payload release show excellent in vitro ability to selectively attack the oxidative stress pathways in the cancer cells, resulting in the execution of the lethal oxidative and apoptosis.