The effects of ozone exposure on apoptotic mechanisms in Colo-320 and Colo-741 cell lines: implications for cancer therapy

This study aimed to investigate the effects of ozone exposure on apoptotic mechanisms in primary (Colo-320) and metastatic (Colo-741) cell lines. Colo-320 and Colo-741 cells were grown in RPMI-1640 medium supplemented with 10% fetal bovine serum and treated with 20 µg/mL ozone for 72 h after MTT assay. Inverted microscopy was used for morphological assessment, and immunocytochemistry followed by H-SCORE analysis was performed to measure the expression of apoptotic markers. The statistical analysis was conducted using unpaired T-tests or Mann–Whitney U tests, with significance set at p < 0.05. Morphological analysis showed no significant changes in cell shape in Colo-320 or Colo-741 cells after ozone exposure. However, immunocytochemical analysis revealed significant increases in semi-quantitative histological scores (H-SCORES) for cleaved caspase-3, Bax, and cytochrome c in both cell lines, indicating enhanced apoptotic activity (p < 0.05). Conversely, Bcl-2 expression was significantly decreased in both Colo-320 and Colo-741 cell lines after ozone exposure (p < 0.05). Ozone exposure promoted apoptosis in both Colo-320 and Colo-741 cell lines, as evidenced by increased pro-apoptotic markers and decreased anti-apoptotic markers. These molecular changes were notable, yet they did not visibly alter cell morphology. The observed similarities between Colo-320 and Colo-741 cell responses suggest the need for further investigation. These findings indicate that ozone exposure may influence tumor cell apoptosis while preserving cell structure, highlighting the necessity of further research into its potential therapeutic implications.