Study on the mechanism of TMZ resistance in brain glioma regulated by copper death

The objective of this study is to investigate the mechanism of cuproptosis regulation in TMZ resistance in GBM, and provide an important theoretical basis for the rational design of combination therapy to block TMZ resistance.

The experimental participants were divided into four groups, including a control group (Control), a Control + CU-ES group, a TMZ group, and a TMZ + copper ion carrier (TMZ + CU-ES) group. TMZ-resistant U87 MG cell lines (U87 MG/TR) were established using a concentration gradient method. Cell proliferation rates were assessed using the CCK8 assay, apoptosis was analyzed via flow cytometry, and gene and protein expression levels of caspase-3 and caspase-9 were detected by using qRT-PCR and Western Blot. Differences in cell proliferation, apoptosis, and apoptosis-related molecule expression were compared across groups.

The U87 MG/TR-resistant strain was established (IC50 =141.5 μM). Compared with the Control group, TMZ group showed a decrease in the cell proliferation rate but an increase in the apoptosis rate (p < 0.05). The TMZ + CU-ES group exhibited a further significant reduction in the cell proliferation rate and a significant increase in the apoptosis rate. The expression of caspase-3 and caspase-9 in the TMZ + CU-ES group was significantly higher than that in the TMZ group.

TMZ resistance in glioma cells was affectively reversed by the cuproptosis pathway, a mechanism likely involving the activation of the intrinsic apoptotic pathway. This finding offered a novel strategy for overcoming TMZ resistance.