摘要
Tyrosine kinase inhibitors for epidermal growth factor receptor(EGFR TKIs)greatly improved clinical outcomes of patients with non-small cell lung cancer(NSCLC).Unfortunately,primary and acquired resistance limits their clinical benefits.To overcome such resistance,new generations of EGFR TKIs have been developed by targeting newly identified mutations in EGFR.However,much less effort has been put into alternative strategies,such as targeting the intrinsic protective responses to EGFR TKIs.In this study,we found that EGFR TKIs,including gefitinib and AZD9291,impaired lysosome-dependent degradation of SQSTM1,thus compromising their anti-cancer efficiency.By accumulating in the lysosome lumen,gefitinib and AZD9291 attenuated lysosomal acidification and impaired autolysosomal degradation of SQSTM1 owing to their intrinsic alkalinity.As a result,SQSTM1 protein was stabilized in response to gefitinib and AZD9291 treatment and conferred EGFR TKI resistance.Depleting SQSTM1 significantly increased the sensitivity of NSCLC cells to gefitinib and AZD9291 both in vitro and in vivo.Furthermore,a chemically modified gefitinib analog lacking alkalinity displayed stronger inhibitory effects on NSCLC cells.Therefore,targeting accumulated SQSTM1 or chemically modified EGFR TKIs may represent new strategies to increase the effectiveness of EGFR targeted therapy.
基金
This work was supported by the National Natural Science Foundation of China#1 under grant no.91740106
the Natural Science Foundation of Zhejiang Province under grant nos.LR19H160003,LQ18H160004,and Q18H160015
the High Level Innovative Talents Program and 151 Talents program in Zhejiang.
