Figure 3.

Inhibition of SUV39H1 enzymatic activity induces ferroptosis and suppresses cell proliferation. (A) 786-O cells were treated with chaetocin (80 nmol/L) or DMSO in the presence and absence of 5 μmol/L Fer-1 (ferrostatin-1), and cell proliferation was evaluated after 3 days. Three view fields were selected to count the number of cells and data was presented as mean ± SD. (B) Transmission electron microscopy analysis of 786-O cells treated with DMSO (24 h) and chaetocin (50 nmol/L, 24 h). (C) and (D) Levels of lipid ROS were analyzed in chaetocin (100 nmol/L) treated 786-O cells. Data was presented as mean ± SD, n = 3. (E) and (F) Levels of mitochondrial superoxide were analyzed in chaetocin (100 nmol/L) treated 786-O cells. Data was presented as mean ± SD, n = 3. (G) and (H) Levels of Fe²⁺ and total iron were analyzed in chaetocin (100 nmol/L) treated 786-O cells. Data was presented as mean ± SD, n = 3. (I) Cell proliferation assay was performed to determine the proliferation ability of ccRCC cells (786-O and Caki-1) treated with chaetocin for 5 days in a dose-dependent manner. The experiment was repeated three times and data was presented as mean ± SD. (J) Treatment with chaetocin suppressed 786-O cell colony formation ability. Three view fields were selected to count the number of cells and data was presented as mean ± SD. (K) and (L) Treatment with chaetocin (30 nmol/L) significantly induced G2/M cell cycle arrest in 786-O cells. Data was presented as mean ± SD, n = 3. (M) Tumor growth curves in chaetocin (0.5 mg/kg/day) treated ccRCC PDX animal model (PDX 1002523691). n = 6 for each group. (N) and (O) Representative photographs of ccRCC PDX animal model tumor tissues treated with chaetocin, and tumor weights were expressed as mean ± SD, n = 6 for each group. ∗P < 0.05, ∗∗P < 0.01, and ∗∗∗P < 0.001.