Peimenine unleashes therapeutic promise in urothelial bladder cancer: inhibition of proliferation, induction of cell death and modulation of key pathways

Peimenine (PEI) is a steroid alkaloid substance isolated from Fritillaria thunbergii bulbs. It has various pharmacological activities, such as relief from coughs and asthma, expectorant properties, antibacterial effects, sedative qualities, and anti-inflammatory properties. Notably, PEI can effectively inhibit the proliferation and tumor formation of liver cancer and osteosarcoma cells by inducing autophagic cell death. However, the precise effect and mechanisms of PEI on urothelial bladder cancer (UBC) cells remain uncertain. Thus, this study aims to investigate the impact of PEI on UBC cells both in vivo and in vitro. The IC₅₀ values of BIU-87 and EJ-1 cells after 48 h were 710.3 and 651.1 μg/mL, respectively. Additionally, PEI blocked the cell cycle in BIU-87 and EJ-1 cells during the G1 phase. Furthermore, it hindered the migration of BIU-87 and EJ-1 cells substantially. PEI significantly inhibited the tumor development of EJ-1 cells within the xenograft tumor model in vivo. Mechanically, PEI augmented the protein and mRNA expression of BIM, BAK1, and Cytochrome C (CYCS) in UBC cells. Taken together, PEI suppressed the proliferation of UBC cells both in vitro and in vivo by inducing cell death and cell cycle arrest, suggesting that PEI could be applied in the treatment of UBC.