Mannose inhibits PKM2 lactylation to induce pyroptosis in bladder cancer and activate antitumor immune responses

Bladder cancer therapy remains challenging due to poor efficacy and frequent recurrence. Mannose, a naturally occurring monosaccharide, has demonstrated antitumor effects in various cancers, yet its mechanism of action in bladder cancer is unclear. This study explored the inhibitory effects of mannose on bladder cancer. We found mannose significantly inhibited the growth of bladder cancer cells, xenografts, and organoids. Mannose directly binds to PKM2, inhibiting its enzymatic activity and reducing lactate production. This reduction in lactate led to decreased PKM2 lactylation and increased acetylation, causing PKM2 to translocate to the nucleus. Nuclear PKM2 activated the NF-κB pathway, inducing NLRP1/Caspase-1/GSDMD/IL-1β-dependent pyroptosis. Additionally, mannose promoted antitumor immune responses by inducing pyroptosis and enhancing the efficacy of immune checkpoint inhibitors. These findings highlight the use of mannose as a potent antitumor agent and a promising therapeutic strategy for bladder cancer.