Protosappanin B promotes apoptosis and causes G1 cell cycle arrest in human bladder cancer cells
The objective of this study was to evaluate the effects of protosappanin B on the proliferation and apoptosis of bladder cancer cells. We assessed the impact of protosappanin B (at concentrations of 12.5, 25, 50, 100, or 200 μg/mL over 48 hours) on the proliferation of SV-HUC-1, T24, and 5637 cells using the MTT assay. Additionally, we analyzed the effects of protosappanin B (at concentrations of 100, 150, 200, 250, or 300 μg/mL over 48 hours) on cell apoptosis and cell cycle using flow cytometry.
T24 and 5637 cells treated with 200 μg/mL protosappanin B exhibited notable morphological changes, including cell shrinkage, rounding, membrane abnormalities, and decreased adhesion. However, protosappanin B did not affect the proliferation of SV-HUC-1 cells. Protosappanin B caused a concentration-dependent inhibition of cell growth, with IC50 values of 82.78 μg/mL for T24 cells and 113.79 μg/mL for 5637 cells. Additionally, protosappanin B induced concentration-dependent increases in apoptosis in T24 and 5637 cells (100-300 μg/mL).
Flow cytometry revealed that protosappanin B caused G1 phase arrest in both T24 and 5637 cells, with a reduction in the proportion of S-phase cells and a lower proliferation index. Proteomics analysis indicated that protosappanin B modulated several genes involved in cell cycle regulation. In summary, protosappanin B inhibits proliferation and promotes apoptosis in T24 and 5637 human bladder cancer cells in a concentration-dependent manner, likely by interfering with cell cycle regulation and preventing the G1-to-S phase transition.