Fig 2: Sestrin2 inhibition significantly decreases oxidative stress in H9c2 cells. (A) Cytometric ROS levels were detected via flow cytometry. (B) Quantitative analysis of ROS levels. (C) SOD, (D) MDA, and (E) mitochondrial SOD kits were used to determine oxidative stress. Data are presented as mean ± SD (n=3). *P<0.001 vs. Control group. &P<0.01 vs. Control group. ^P<0.001 vs. HG group. §P<0.01 vs. HG group. #P<0.001 vs. Negative control group. Sesn2, Sestrin2; C, control group; G, HG group; NC, negative control; shRNA, small hairpin RNA; HG, high glucose.

Fig 3: Sestrin2 inhibition significantly increases cell viability and decreases cell apoptosis in H9c2 cells under hyperglycemic conditions. (A) Cell viability was determined by MTS assay after cell treatments. (B) The apoptotic rate of H9c2 cells was detected via flow cytometry. (C) Quantitative analysis of the apoptotic rate. Data are presented as mean ± SD (n=3). *P<0.001 vs. Control group. &P<0.01 vs. Control group. ^P<0.001 vs. HG group. #P<0.001 vs. Negative control group. Sesn2, Sestrin2; C, control group; G, HG group; NC, negative control; shRNA, small hairpin RNA, HG, high glucose.

Fig 4: SESN2 inhibited H2O2-induced oxidative stress in SAR01/04 cells. (a)–(d) SRA01/04 cells were transfected with si-NC or si1-SESN2 and then treated with 200 μM H2O2 for 24 h; SOD activity (a), CAT activity (b), MDA level (c), and ROS level (d) were measured. (e)–(h) SRA01/04 cells were transfected with pcDNA-NC or pcDNA-SESN2 and then treated with 200 μM H2O2 for 24 h; SOD activity (e), CAT activity (f), MDA level (g), and ROS level (h) were measured. The mean ± standard deviation is the presentation form of the data. N = 3. Compared with the control group, **p < .01; compared with the H2O2 + si-NC or H2O2 + pcDNA-NC group, #p < .05 and ##p < .01.

Fig 5: Suppression of SESN2 increases sensitivity to chemotherapy in vivo. NU/NU nude mice were subcutaneously injected with SESN2-knockdown or control 143B cells. After 7 days, the mice were intraperitoneally injected with Cis (20 μmol/L) until they were killed on day 28. Tumour volume was measured on day 28 (A) (n = 3). Tumour growth curves were measured from days 7 to 28 (B) (n = 3). Tumour weight was measured on day 28 (C) (n = 3). Immunofluorescence staining of TUNEL, SESN2 expression, LC3 expression, P62 expression, p-mTOR expression, Bcl-2 expression, PERK expression, CHOP expression and p-eIF2α expression after tumour sample injection (D) (n = 3, scale bar = 50 μm). The data are presented as the mean ± SD. *p < 0.05 vs. the Control shRNA + Cis group.