DMC-BH derivative DMC-GF inhibits the growth of glioma stem cells by targeting the TRIM33/SLC25A1/mitochondrial oxidative phosphorylation pathway

Glioma stem cells (GSCs) exhibit significant resistance to conventional radiotherapy and chemotherapy, contributing to high recurrence rates in gliomas. Addressing this critical clinical need, we developed DMC-GF, a novel GLUT1-based curcumin derivative, to enhance brain specificity and metabolic stability compared to its predecessor DMC-BH. Pharmacokinetic studies in rats demonstrated that DMC-GF achieved an 8.5-fold increase in brain-to-blood concentration ratio two hours post-intravenous administration, markedly superior to the 0.2-fold increase observed with DMC-BH. In vitro assays showed that DMC-GF exerted a more substantial inhibitory effect on GSC proliferation than DMC-BH (p < 0.01), as assessed by Cell Counting Kit-3D and EdU assays. Mechanistic analysis via the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway indicated that DMC-GF's anti-GSC activity is associated with disruption of mitochondrial oxidative phosphorylation. Treatment with DMC-GF at a concentration of 4 µM caused a notable decrease in mitochondrial membrane potential and maximal mitochondrial oxygen consumption. Additionally, exposure to 8 µM DMC-GF led to a marked (> 70%) reduction in SLC25A1, a mitochondrial citrate transporter, protein levels (p < 0.01). Overexpression of SLC25A1 attenuated both the decreased proliferation and enhanced apoptosis caused by DMC-GF (p < 0.01). Furthermore, the proteasome inhibitor MG132 (10 µM) and TRIM33, an E3 ubiquitin ligase involved in proteasome-mediated protein degradation, knockdown via shRNA both abrogated the DMC-GF-mediated decrease in SLC25A1 protein levels (p < 0.05). These findings underscore the potential of DMC-GF as an efficacious targeted therapeutic against GSCs, offering enhanced brain specificity and stability, and elucidating its mechanism involving mitochondrial dysfunction and SLC25A1 degradation.