Curcumol Induced Autophagy In Nasopharyngeal Carcinoma Cells By Inactivating PI3K/AKT/mTOR Pathway Via Nucleolin-RNA Binding Domain

Objective: Excessive autophagy induces cell death and which was regarded as the treatment of cancer.Previous studies confirmed that the anti-cancer mechanism of curcumol is related to autophagy induction.As the main target and RNA-binding protein of curcumol interacted with many tumor promoters accelerating tumor progression.However,the role of NCL in cancer autophagy and in curcumol’s anti-tumor effects have not been elucidated.The purpose of our study was to identify the role of NCL in nasopharyngeal carcinoma autophagy and reveal the immanent mechanisms of NCL-RBD played in cell autophagy.Methods: Lentiviral infection was used to construct NCL overexpression,silencing nasopharyngeal carcinoma cell lines,Western blotting,autophagy fluorescence assay,immunofluorescence(IF)and transmission electron microscopy(TEM)were used to detect the relationship between NCL expression and autophagy,and the effect of curcumol on NCL expression and autophagy induction;IP and IF assay detected interaction between NCL and AKT;After combination of curcumol with autophagy inhibitor 3-MA,autophagy activator Rapa and AKT inhibitor MK2206,MTT was used to detect the effect of pharmaceuticals on cell viability;The production of cellular ROS was detected by DHE;The expression of autophagy related proteins and PI3K/AKT/m TOR pathway related proteins were detected by Western blotting;The xenograft tumor model was established in nude mice,and the mice were randomly divided into normal control group,curcumol group and cisplatin positive drug group in order to reveal that NCL play a role in curcumol’s anti-cancer.The RBD deletion mutant cell lines of NCL was constructed by transient transfection,and the target RBD was truncated by MTT,Western blotting and IP screening.Results:(1)Reduction of NCL expression induced autophagy in NPC C666-1 cells.(2)Curcumol induced autophagy in C666-1 cell lines via the decrease of NCL.(3)IP results showed that NCL interacted with AKT,and NCL reduction could inhibit PI3K/AKT/m TOR signal pathway.(4)Curcumol inhibited PI3K/AKT/m TOR signaling pathway via the reduction of NCL in C666-1 cells.(5)Curcumol,Rapa and MK2206 could inhibit the proliferation of C666-1 cells.3-MA reversed the proliferation inhibition caused by curcumol.(6)Curcumol,Rapa and MK2206 could induce the production of ROS,3-MA reverse the ROS release caused by curcumol.(7)Curcumol induced autophagy and inhibited PI3K/AKT/m TOR signal pathway was related with the expression of NCL in C666-1 cells.(8)In vivo,NCL silence significantly inhibited the growth of NPC,curcumol could inhibit the growth of tumor with high expression of NCL and inhibit PI3K/AKT/m TOR pathway related proteins.(9)RNA-binding domain 2 of nucleolin played a crucial role in the autophagy induction of curcumol in NPC cells.Conclusion: Curcumol induced autophagy in NPC cells by inactivating PI3K/AKT/m TOR signal pathway via NCL-RBD2.