Fig 2: CISD2 is vital for maintaining redox homeostasis and the mitochondrial function in LUAD cells. (A) The oxygen consumption rate (OCR) of control and CISD2 silenced cells were measured in real time using the Seahorse XF24 Analyzer. Basal OCR was measured at three time points, following sequential injection of oligomycin (1.5 μM), FCCP (1.5 μM), rotenone (0.5 μM), and antimycin A (0.5 μM). The overall OCR curves were plotted as the mean OCR ± SD of three replicates. (B) Maximal respiration, spare respiration, the level of proton leak, and ATP production were calculated according OCR curves, respectively. Data are presented as the mean ± SD, **P < 0.01. (C) Cellular ROS levels were detected by flow cytometry in CISD2 knockdown cells. Representative images (left) and statistical graphs (right) are shown; **P < 0.01, compared to the control group. (D) Mitochondrial ROS levels were detected by flow cytometry in CISD2 knockdown cells. Representative images (left) and statistical graphs (right) are shown; *P < 0.05, compared to the control group. After treatment of 0.5 mM tBH for 15 min, cells were washed and incubated with complete culture medium (0 h); cellular ROS (E) and MitoSOX (F) were detected in the indicated time. Comparable results were obtained in three independent experiments.

Fig 3: Pan-cancer analysis of the relationship between CISD2 expression and overall survival in 33 TCGA tumors. (A) The hazard ratio for overall survival of CISD2 in 33 tumors; the forest diagram was showed in the right. (B) Overall survival curves in LUAD, HNSC, KICH, UVM, LGG, and LIHC, respectively.

Fig 4: Overall survival curves of LUAD samples based on the expression of CISD2. The Kaplan-Meier plot shows the overall survival of LUAD samples from GSE31210 (A) and GSE13213 (B) datasets by CISD2 expression.

Fig 5: CISD2 silencing lowered DEX-mediated inhibitory effect on ferroptosis in lidocaine-stimulated PC12 cells. (A) Detection of CISD2, FTH1, SLC7A11, GPX4, and NCOA4 protein levels in the epicenter of the injured spinal cord in the control, lidocaine, and lidocaine + DEX groups. (B-C) Detection of CISD2, FTH1, SLC7A11, GPX4, and NCOA4 protein levels in PC12 cells in control, lidocaine, lidocaine + DEX, or lidocaine + DEX + si-CISD2 groups. (D) MTT analysis of the viability of PC12 cells in different groups. (E-G) Measurement of MDA, GSH, and Fe2+ levels in PC12 cells in different groups. (H) Detection of the levels of ROS was made by flow cytometry. Data are presented as the mean ± standard deviation (n = 3)