MFAP4 activates PI3K/AKT–NF-κB signaling to drive tumor progression and immune evasion in bladder cancer

Response rates to single-agent PD-1/PD-L1 blockade in bladder cancer remain modest, underscoring the need for alternative, targetable axes. Microfibril-associated protein-4 (MFAP4) is dysregulated in cancers, yet its role in bladder cancer is unclear. MFAP4 was prioritized by differential expression analysis of GSE236932 comparing tumor and adjacent normal tissues, followed by pathway level annotation using GO KEGG and GSEA and immune state quantification using a rank mean single sample scoring framework. An immune extracellular matrix co expression network was built to position MFAP4 within key modules, then clinical relevance was validated in TCGA and GEPIA. MFAP4 loss and gain of function models were profiled for proliferation, migration, invasion and apoptosis. RNA-seq with GO and KEGG enrichment, immunoblotting and pharmacologic modulation defined signaling. QRTpcr, WB, and ChIP-qPCR established PI3k/Akt/NF-κB dependent regulation of PVR. Immune states in GSE236932 were quantified by a rank-mean single-sample scoring scheme. Immune consequences were tested in mouse splenic T cell MB49 co-cultures and C57BL/6 syngeneic tumors with PVR rescue. GSE236932 showed broad transcriptional dysregulation dominated by immune and extracellular matrix programmes, with GSEA and network analysis linking MFAP4 to an immune ECM hub and tumor analyses further showing that high MFAP4 was associated with higher immune module and immunosuppressive scores. Clinically, Higher MFAP4 transcripts are associates with lymphovascular invasion, advanced T/N/Stage, and poorer survival; IHC and cell lines indicate augmented MFAP4 activity in tumors. Functionally, MFAP4 promotes proliferation, clonogenicity, migration and invasion while inhibiting apoptosis. Mechanistically, MFAP4 activates the PI3K/AKT/NF-κB cascade; pathway activation and inhibition is reversible pharmacologically. NF-κB binds the PVR promoter and drives its transcription; MFAP4 up regulates PVR. MFAP4 knockdown enhances T cell mediated lysis and cytokines, increases intratumoral CD8 + infiltration and activation, and suppresses tumor growth, whereas PVR re-expression partially rescues these phenotypes. In the cohort, MFAP4 correlates positively with immunosuppressive signatures (exhausted CD8, T cell exclusion). MFAP4 orchestrates an immune-evasive MFAP4/PVR axis by activating PI3K/AKT/NF-κB, thereby suppressing T cell effector function and driving progression. This axis represents a therapeutic target and risk-stratification biomarker, supporting a strategy of upstream blockade combined with downstream checkpoint relief. MFAP4 drives bladder cancer progression and remodeling an immunosuppressive microenvironment—via PI3K/AKT–NF-κB activation that upregulates PVR, promotes checkpoint programs and T-cell dysfunction, and enriches suppressive signatures. • MFAP4 is markedly correlates with aggressive clinicopathological features and poor prognosis. • MFAP4 drives malignant phenotypes by activating the PI3K/AKT–NF-κB signaling pathway. • MFAP4-induced NF-κB activation directly upregulates PVR, linking oncogenic signaling to immune checkpoint regulation. • The MFAP4-PVR axis suppresses T-cell activation and promotes tumor immune evasion.