Exploring the mechanism by which triphenyl phosphate promotes malignant phenotypes in bladder and kidney cancer...

Background Bladder and kidney cancer burden rises globally, with environmental toxicants driving their progression. Methods We integrated global epidemiological analysis, single-cell transcriptomics, cell-cell communication analysis, epithelial subclustering, pseudotime inference, toxicological target prediction, survival modeling, cross-cohort validation, single-cell virtual knockout, spatial transcriptomic deconvolution, molecular docking/dynamics, CETSA, and in vitro assays to define a shared molecular interface linking triphenyl phosphate (TPP) to bladder and kidney cancer. Results Both malignancies exhibited age- and SDI-associated burden patterns. Single-cell profiling identified conserved epithelial, stromal, and immune ecosystems, with tumor epithelial cells occupying central positions in intercellular communication networks. Epithelial subclustering revealed a reproducible EMT-high subcluster 4 in both cancers, which localized to a terminal-like pseudotime state and was associated with poor survival. Predicted TPP targets intersected with subcluster 4 signatures and converged on extracellular matrix organization, adhesion, and leukocyte transendothelial migration pathways. Integrative survival modeling and multi-cohort validation identified MMP9 as a robust prognostic candidate associated with tumor progression. Importantly, single-cell virtual knockout of MMP9 revealed convergent remodeling of proliferative, inflammatory, hypoxia-related, and stress-response programs across bladder and renal cancer epithelial cells, highlighting conserved regulatory circuitry. Spatial transcriptomics further localized MMP9 to macrophage- and fibroblast-enriched niches in both tumor types. Structural modeling and CETSA supported an interaction between TPP and MMP9. Experimentally, TPP upregulated MMP9 at both mRNA and protein levels in T24 and 786-O cells; higher concentrations reduced viability, whereas lower concentrations enhanced migration and clonogenic growth. Conclusions TPP promotes the malignant phenotypes of bladder and kidney cancer via MMP9, which is validated by virtual knockout and in vitro experiments.