Enhanced therapeutic efficacy of asparaginase and chloroquine co-loaded ZIF-8 nanoparticles for overcoming l-asparaginase resistance in leukemia treatment

Abstract

l-Asparaginase (ASNase) is a therapeutic enzyme that degrades asparagine, an essential amino acid for leukemic cells. However, ASNase resistance can arise from cellular mechanisms such as Asparagine synthetase upregulation and cytoprotective autophagy. To overcome these challenges, we developed AC@ZIF-8 nanoparticles loaded with ASNase and chloroquine (CQ), an autophagy inhibitor, for enhanced therapeutic outcomes via combining amino acid starvation and autophagy inhibition mechanisms. AC@ZIF-8 exhibited a particle size of ∼123 nm, zeta potential of −20 mV, polydispersity index of 0.3, and pH-responsive release for ASNase and CQ over 54 h. The optimum dosage ratio of ASNase and CQ in AC@ZIF-8 was determined based on their respective cytotoxicity on chronic myeloid leukemia cells (K562) and it was found to be 1:5. The encapsulation efficiencies were 80 % and 85 %, and the drug loading capacities were 5 % and 15 %, for ASNase and CQ, respectively. More importantly, we demonstrated that ZIF-8 nanoparticles effectively delivered ASNase and CQ intracellularly, resulting in inducing significant cytotoxic effect in ASNase-resistant leukemic cells (K562) (IC50 = 3.2 μg/mL). The quantitative measurement of autophagy biomarkers showed that CQ blocked the autophagy caused by ASNase, thereby leading to increased reactive oxygen species (ROS) and the number of apoptotic cells. Taken together, our findings suggest that AC@ZIF-8 nanoparticles can overcome ASNase resistance and enhance therapeutic outcomes in leukemia treatment.