MOF Nanoparticles with Encapsulated Autophagy Inhibitor in Controlled Drug Delivery System for Antitumor.

High porosities, large surface areas, and tunable functionalities made metal-organic frameworks (MOFs) as effective carriers for drug delivery. One of the most promising MOFs is the zeolitic imidazolate framework (ZIF-8) crystal, an advanced functional material for small-molecule delivery, due to its high loading ability and pH-sensitive degradation. As a novel carrier, ZIF-8 nanoparticles were used in this work to control the release of an autophagy inhibitor, 3-methyladenine (3-MA), and prevent it from dissipating in a large quantity before reaching the target. The cellular uptake in HeLa cells of 3-MA encapsulated in ZIF-8 (3-MA@ZIF-8 NPs) is facilitated through the nanoparticle internalization with reference to TEM observations and the quantitative analyses of zinc by ICP-MS. The autophagy-related proteins and autophagy flux in HeLa cells treated with 3-MA@ZIF-8 NPs show that the autophagosome formation is significantly blocked, which reveals that the pH-sensitive dissociation increases the efficiency of autophagy inhibition at the equivalent concentration of 3-MA. In vivo experiments, when compared to free 3-MA, 3-MA@ZIF-8 NPs show a higher antitumor efficacy and repress the expression of autophagy-related markers, Beclin 1 and LC3. It follows that ZIF-8 is an efficient drug delivery vehicle in antitumor therapy, especially in inhibiting autophagy of cancer cells.