The role of ASPP2 in starvation-induced autophagy and apoptosis of HCT116 cell line / 中华普通外科杂志

ABSTRACT

Objective To investigate the role of ASPP2 (apoptosis stimulating protein 2 of p53,ASPP2) in starvation-induced autophagy and apoptosis of colorectal cancer HCT116 p53-/-(p53 gene deletion) cell line.Methods The study included three experiment groupsgreen fluorescent protein adenovirus (rAd-GFP) infection group,autophagy inhibitor LY294002 treatment group and ASPP2 adenovirus (rAd-ASPP2) infection group.Celluar autophagy and apoptosis were induced by coculturing with serum-free medium for 0 h,24 h,48 h.Apoptosis level was detected by Calcein/PI uptaking test.Autophagy level was observed under the fluorescence microscope via transfection with cerise fluorescent protein autophagy plasmid CFP-Lc3.Results In control group,starvation for 24 hours significantly promoted autophagy of HCT116 cells (0 h1.04 ±0.24; 24 h12.17 ±0.86,P ＜0.05),while apoptosis was not increased (0 h2.01％ ±0.06％; 24 h3.23％ ±0.34％,P ＞0.05).With 48 h starvation,autophagy(0 h1.04 ±0.24; 48 h21.09 ±3.32) and apoptosis(0 h2.01％ ±0.06％ ; 48 h30.20％ ±3.18％)of HCT116 increased (P ＜ 0.05).With the use of LY294002 apoptosis induced by 24 h starvation significantly increased (rAd-GFP group3.23％ ± 0.34％ ; LY294002 group15.68％ ± 1.24％,P ＜0.01),but aopotosis under 48 h starvation decreased (rAd-GFP group30.20％ ± 3.18％; LY294002group25.44％ ± 3.01％,P ＜ 0.05).With ASPP2 transfection,autophagy under 24 h starvation significantly declined (rAd-GFP group12.17 ± 0.86,ASPP2 group1.45 ± 0.45,P ＜ 0.01),and apoptosis increased(rAd-GFP group3.23％ ± 0.34％ ; ASPP2 group10.45％ ± 0.81％,P ＜ 0.05).Both autophagy (rAd-GFP group21.09 ± 3.32; ASPP2 group29.93 ± 3.48) and apoptosis (rAd-GFP group30.20％ ±3.18％ ; ASPP2 group36.72％ ±2.74％) were higher than that in controls under 48 h starvation (P ＜ 0.05).Conclusions ASPP2 probably promotes apoptosis of colorectal cancer cells by two-way regulated autophagy.