Celastrol-Loaded Ultrafine Iron Oxide Nanoparticles for Targeted Drug Delivery in Glioblastoma Multiforme

Objective Investigate the inhibitory effect of iron oxide nanoparticles (Fe 3 O 4 @Cel) containing rhein from Celastrol (Cel) on glioblastoma multiforme (GBM) and the underlying mechanism. Method Fe 3 O 4 @Cel was synthesized, and its characteristics were evaluated through chemical and physical analysis and observed directly under a transmission electron microscope. The inhibitory effect of Fe 3 O 4 @Cel on GBM was monitored by constructing in situ GBM cell tumors and axillary transplantation tumor animal models, and the in vivo safety of Fe 3 O 4 @Cel was evaluated by measuring the body weight, liver and kidney serum indicators, and Hematoxylin-eosin staining (HE) indices of important organs such as heart, liver, spleen, lung, and kidney. After C6, U251, and U87-MG cells were intervened with Fe 3 O 4 Cel, the cell survival ability was detected using the Cell Counting Kit-8. The cell proliferation, invasion, and migration abilities were verified through plate cloning and transwell migration and invasion experiments. The morphological changes of cell ferroptosis were detected by transmission electron microscopy. Western blotting proved the expression levels of cell ferroptosis markers. The changes in IL-18 and IL-1β contents in the culture medium after Fe 3 O 4 @Cel intervention were detected by Elisa experiments. The construction of stable overexpressed and low-expressed GSDME gene GBM cell lines further verified the certainty of the mechanism of Fe 3 O 4 @Cel in inhibiting GBM. Result The successfully synthesized Fe 3 O 4 @Cel has a hydrated particle diameter of approximately 120 nanometers and a Zeta potential of -50.99. Fe 3 O 4 @Cel has inhibitory effects on both in situ GBM and axillary transplanted tumor models of tumors, and no significant changes in liver and kidney indicators or substantial damage to important organs were observed. In vitro, Fe 3 O 4 @Cel has inhibitory effects on C6, U251, and U87-MG cells. Compared with the control group, the transmission electron microscopy results of the Fe 3 O 4 @Ce group indicate that the pyroptosis phenomenon of C6 and U87-MG cells is significantly increased, and their migration and invasion abilities are significantly weakened. In addition, the expression of pyroptosis-related proteins Cleaved-Caspase-3 and GSDME-N, as well as the contents of IL-18 and IL-1β in the cell culture medium, have all increased. The transfection results indicate that the GSDME gene is one of the key effector genes for pyroptosis in C6 and U87-MG cells. Conclusion The Fe 3 O 4 @Cel nanomaterials possess stable characterization properties and exhibit certain anti-GBM cell activity both in vitro and in vivo. This process is dependent on the activation of Caspase-3/GSDME cell pyroptosis signaling by Fe 3 O 4 @Cel. Moreover, no substantial damage to important organs and functions was observed in the body due to Fe 3 O 4 @Cel. Graphical Abstrac: Fe 3 O 4 @Cel synthesis and the mechanism by which Fe 3 O 4 @Cel promotes pyroptosis and activates immune cell populations among GBM cells . We synthesized Fe 3 O 4 @Cel by high-temperature pyrolysis and a phase-transfer method, which enabled Cel to be loaded into Fe 3 O 4 nanocarriers. Fe 3 O 4 @Cel activated caspase-3 in GBM cells, and activated caspase-3 cleaves full-length GSDME, which separates its N-terminus from its C-terminus. This process promotes pyroptosis in GBM cells and the release of IL-18 and IL-1β into the TME, which activates immune cell populations, such as NK and T cells, in the TME. The promotion of pyroptosis in GBM cells enhances the anti-GBM effect of immune cells. Download: Download high-res image (305KB) Download: Download full-size image