7β-22 Dihydroxyhopane, Isolated from the Sub-Antarctic Lichen, Inhibits the Viability and Stemness in Glioma Stem Like Cells

Abstract

Glioma stem cells (GSCs) have been reported to contribute to tumor initiation and relapse, therapy resistance, and intra-tumoral heterogeneity of glioblastoma multiforme. Therefore, inhibiting GSCs presents a critical therapeutic tactic to suppress the aggressiveness of tumors. In this study, we examined the effects of 7β-22 dihydroxyhopane (AP 18), isolated from the sub-Antarctic lichen, Pseudocyphellaria freycinetii. The cytotoxic effect of AP 18 and its effects on cell proliferation were assessed by alamarBlue assay and 5-ethynyl-2'-deoxyuridine (EdU) assay. Real-time confluence analysis was performed with a Celloger automatic live cell imaging system. Western Blotting and 3-D optical diffraction tomography (ODT) imaging were performed to determine whether apoptosis was triggered by AP 18. A Limiting dilution assay and qRT-PCR were performed to investigate the impact of AP 18 on GSC stemness. AP 18 significantly reduced GSCs viability and proliferation, inducing programmed cell death identified by Annexin V/PI staining and had effects on morphologic features determined by 3-D ODT. Interestingly, treatment with AP 18 suppressed stemness features. Taken together, our results suggest that AP 18 might be a potential therapeutic agent to target GSCs.