stellettin B

Stellettin B (SP-2) is a marine-derived isomalabaricane-type triterpene isolated from the sponge *Jaspis stellifera*. It has demonstrated significant anti-tumor activity in preclinical models, particularly against bladder cancer. The compound induces cell death through two primary pathways: apoptosis and autophagy. In human bladder cancer RT112 cells, stellettin B triggers subG1 phase accumulation and activates apoptotic proteins. Simultaneously, it induces autophagy, characterized by the formation of LC3-II and the downregulation of p62. Notably, research indicates that the autophagy induced by stellettin B is a pro-death mechanism, as its inhibition—either pharmacologically or through ATG5 knockout—attenuates the drug's pro-apoptotic and anti-proliferative effects. Stellettin B shows selective toxicity, suppressing cancer cell viability without significant harm to normal uroepithelial cells, making it a potential candidate for further therapeutic development.