Abstract: Objective To investigate the growth-inhibitory and pro-apoptotic effects of piroctone olamine (PO) on glioma cells and explore the underlying mechanism. Methods Human glioma cell lines U251 and U373 were treated with PO and the changes in cell proliferation were detected using CCK-8 assay and EdU assay. Clone formation assay and flow cytometry were used to examine the changes in clone formation ability and apoptosis of the treated cells. Mitochondrial membrane potential of the cells and morphological changes of the mitochondria were detected using JC-1 staining and a fluorescence probe, respectively. The expressions of mitochondrial fission protein DRP1 and the fusion protein OPA1 were determined with Western blotting. Transcriptome sequencing and differential gene enrichment analysis was performed, and the expression levels of PI3K, AKT and p-AKT in the treated cells were verified using Western blotting. Results CCK-8 assay showed that PO significantly inhibited the proliferation of U251 and U373 cells in a time- and dose-dependent manner (P<0.001). EdU test showed that the proliferative activity of PO-treated cells was significantly decreased, and the number of cell colonies also decreased significantly (P<0.01). PO treatment significantly increased apoptotic rates (P<0.01), decreased mitochondrial membrane potential and caused obvious changes in mitochondrial morphology of the cells. Pathway enrichment analysis showed that the down-regulated genes were significantly enriched in the PI3K/AKT pathway, which was verified by Western blotting showing significantly down-regulated expression levels of PI3K, AKT and p-AKT in PO-treated cells (P<0.05). Conclusion PO interferes with mitochondrial fusion and fission function through the PI3K/AKT pathway, thereby inhibiting the proliferation and increasing apoptosis of glioma cells.

Key words: piroctone olamine; mitochondrial fission; glioma; PI3K/AKT pathway