Impacts of sirolimus on apoptosis and autophagy of cutaneous squamous cell carcinoma cells by regulating the Akt/mTOR signaling pathway

YANG Xi; WANG Xiaoxiao

doi:10.3969/j.issn.1002-7386.2025.06.002

Abstract：Objective To investigate the impacts of sirolimus(SIR)on apoptosis and autophagy of cutaneous squamous cell carcinoma(cSCC)cells by regulating the serine/threonine kinase(Akt)/mammalian target of rapamycin(mTOR)signaling pathway.Methods The cSCC cell line A431 was induced with blank control,low-dose,medium-dose and high-dose SIR,and the mTOR activator 3BDO.EdU staining was performed to detect the proliferation of A431 cells.Transwell assay was applied to detect the migration and invasion of A431 cells.Flow cytometry was applied to detect apoptosis of A431 cells.Monodansylcadaverine(MDC)was used to label autophagic vacuoles in A431 cells.Transmission electron microscopy(TEM)was applied to detect autophagic structures.Western blotting(WB)was applied to detect the expressions of Caspase-3,LC3 Ⅰ,LC3 Ⅱ,Beclin1,p-Akt,Akt,p-mTOR,and mTOR proteins in A431 cells.Results Compared with those of blank control,A431 cells induced with low-dose,medium-dose and high-dose SIR had significantly lower EdU-positive cell ratio,migratory and invasive cell numbers,p-Akt/Akt and p-mTOR/mTOR,but higher apoptotic rate,fluorescence intensity,number of autophagic vacuoles,and expression levels of Caspase-3,LC3 Ⅱ/LC3 Ⅰ and Beclin1(P＜0.05).Compared with those induced with high-dose SIR,3BDO-induced A431 cells had significantly higher EdU-positive cell ratio,migratory and invasive cell numbers,p-Akt/Akt and p-mTOR/mTOR,but lower apoptotic rate,fluorescence intensity,number of autophagic vacuoles,and expression levels of Caspase-3,LC3 Ⅱ/LC3 Ⅰ and Beclin1(P＜0.05).Conclusion SIR can induce autophagy and apoptosis of cSCC cells by inhibiting the Akt/mTOR signaling pathway.