SNORD99 promotes endometrial cancer development by inhibiting GSDMD-mediated pyroptosis through 2'-O-methylation modification.

Eukaryotic cells possess multiple mechanisms of self-destruction, including pyroptosis and necroptosis. Pyroptosis is a type of programmed cell death characterized by cellular rupture and linked to inflammation. SnoRNA, a small non-coding RNA in the nucleolus, can dysregulate specific RNAs through 2'-O-methylation, contributing to tumorigenesis. Our StarBase and qRT-PCR analysis revealed SNORD99 upregulation in endometrial cancer (EC) tissue compared to normal tissue, suggesting its role in pathogenesis. SNORD99 overexpression enhanced migration and proliferation of EC cells, while ASO-mediated suppression reduced malignant cell spread and division. RNA-seq and base-comparing analysis identified GSDMD's differential expression upon SNORD99 overexpression, forming the SNORD99-FBL RNP complex. RTL-P experiments showed SNORD99 increased GSDMD's 2'-O-methylation. SNORD99 reduced GSDMD, caspase-1, and NLRP3 protein levels, implicating its role in pyroptosis. Optical and electron microscopy confirmed enhanced pyroptosis features. In summary, SNORD99 modifies GSDMD via 2'-O-methylation, suppressing pyroptosis and promoting EC progression. Developing pyroptosis-inducing drugs may offer new cancer treatment avenues.