In vitro demonstration of salinomycin as a novel chemotherapeutic agent for the treatment of SOX2‑positive glioblastoma cancer stem cells.

Glioblastoma multiforme (GBM) is the deadliest and most common form of primary brain tumor. Conventional treatments are ineffective at treating GBM due to the heterogeneous cellular makeup of the tumors as well as the existence of drug‑resistant cells known as cancer stem cells (CSCs). CSCs have the ability to initiate tumorigenesis and self‑renew, which can lead to recurrence. Salinomycin, an antibiotic commonly used in agricultural feed, has been revealed to target CSCs in other cancer types. A few studies have suggested salinomycin can be effective at treating glioblastoma stem cells (GSCs); however, no study has examined the effect of salinomycin treatment on GSC markers. In the present study, flow cytometry, RT‑qPCR, and limiting dilution assays were used to further analyze the effects of salinomycin on GSCs. It was revealed that salinomycin decreased the expression of the GSC marker SOX2 at both the transcriptional and translational level. However, the effect of salinomycin on the GSC markers Nestin and CD133 was inconsistent between GBM subtypes. Additionally, the present findings provide initial evidence of caspase‑3‑dependent and independent apoptosis as the method by which salinomycin induces cell death in GBM. The present results indicated that salinomycin is an effective candidate as a chemotherapeutic agent that can treat GBM by targeting both bulk tumor cells as well as CSCs.