Mechanism of salinomycin-induced oncosis in adipose-derived stem cells and hepatocellular carcinoma stem cells via Na+,K+-ATPase
Objective Salinomycin,an ionophore antibiotic,has been reported to selectively kill cancer stem cells.However,the underlying mechanism remains unclear.This study investigated the responses of adipose-derived stem cells(ASCs)and hepatocellular carcinoma stem cells(HCCSCs)to salinomycin treatment and explored the underlying mechanisms.Methods The cytotoxic effects of salinomycin on ASCs and HCCSCs were analyzed using CCK-8 and Transwell assays,while morphological changes of cells were observed under a microscope.Intracellular Na+and K+ion concentrations were measured using a Na+,K+-ATPase assay kit,and ATP levels were determined with an ATP assay kit.Additionally,the expression levels of Na+,K+-ATPase subunits and cell epithelial-mesenchymal transition(EMT)related proteins were examined using Western blot analysis.These methods were employed to investigate the mechanism by which salinomycin induces oncosis(cellular swelling and necrosis)in ASCs and HCCSCs through the regulation of Na+,K+-ATPase.Results This study observed that salinomycin selectively induced cellular and organelle swelling in ASCs and HCCSCs,morphologically defined as oncosis.In oncotic ASCs and HCCSCs,intracellular ATP concentration was significantly reduced,accompanied by a loss of Na+,K+-ATPase activity and retention of intracellular Na+.All types of Na+,K+-ATPase subunits were expressed in ASCs,whereas only the α1 and β1 subunits were expressed in salinomycin-induced differentiated ASCs.Additionally,this study found that the loss of β1 subunits was a key event in doxorubicin-induced EMT in Huh-7 cells,and overexpression of β1 subunits could inhibit doxorubicin-induced EMT in Huh-7 cells.Conclusion The study demonstrates that the difference in Na+,K+-ATPase activity determined by subunits is the reason for the selective cytotoxicity of salinomycin on stem cells,and that the β1 subunit serves as a key marker in the HCC EMT process.These results indicate that Na+,K+-ATPase subunits play a key role in the stemness of ASCs and HCCSCs,as well as in the cancer stem cell-like EMT process.