Integrated analyses identify MAN1B1 as a candidate regulator of chemotherapeutic tolerance and immunosuppression in bladder cancer

Background Gemcitabine (GEM) resistance limits treatment efficacy in bladder cancer (BC). This study identified MAN1B1 as a key driving factor for chemotherapy resistance and malignant progression in BC. Methods Bulk-RNA datasets GSE190636 and single-cell RNA-seq dataset GSE250523 from GEO. Use limma package to identify differentially expressed genes (DEGs) in the process of GEM resistance, and then perform GO and KEGG enrichment analysis. Screening candidate targets through molecular docking with GEM, and further evaluation through molecular dynamics simulation and GEPIA survival analysis. GSEA analysis is used to explore pathways associated with key genes. Perform single-cell analysis using Seurat, SingleR, Monocle 2, CellChat, and scTenifoldKnk, including cell annotation, pseudo time trajectory, intercellular communication, and virtual knockout. Carry out functional experiments in bladder cancer cell lines, including cell viability, wound healing Transwell, Colony formation and Western blot analysis. Results Through comprehensive transcriptome analysis and single-cell sequencing, we found that elevated levels of MAN1B1 are associated with poorer clinical outcomes. Computational molecular docking and molecular dynamics simulations indicate the potential binding interaction between MAN1B1 and GEM.This enzyme orchestrates a dual microenvironmental reprogramming by hyperactivating metabolic cascades while simultaneously dampening anti-tumor immune surveillance, predominantly originating from the epithelial compartment to modulate intercellular crosstalk. Functional disturbance experiments showed that knockout of MAN1B1 was associated with decreased cell survival, migration, and invasion, as well as increased sensitivity to GEM, while ectopic expression of MAN1B1 increased cell survival and was associated with enhanced PI3K/AKT/mTOR pathway activity. Conclusions Our findings uncover the multifaceted regulatory network governing MAN1B1, establishing its utility as an innovative prognostic indicator and an actionable therapeutic vulnerability for overcoming GEM insensitivity in urological oncology.