Attenuated expression of SNF5 facilitates progression of bladder cancer via STAT3 activation

Background: SWI/SNF, a well-known ATP-dependent chromatin-remodeling complex, plays an essential role in several biological processes. SNF5, the core subunit of the SWI/SNF remodeling complex, inactivated in 95% of malignant rhabdoid tumors (MRT), highlighting its significance in tumorigenesis. However, the role of SNF5 in bladder Cancer (BC) remains unknown. In this study, we aimed to investigate the function and potential clinical applicability of SNF5 in BC.

Methods: Data from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO) and Cancer Cell Line Encyclopedia (CCLE) databases were used to evaluate the clinical significance of SNF5 in BC. We performed Gene Set Enrichment Analysis (GSEA) and functional assays to investigate the role of SNF5 in BC. Genomics of Drug Sensitivity in Cancer (GDSC) and drug-susceptibility tests were performed to identify the potential value of SNF5 in the treatment of BC.

Results: Low SNF5 expression conferred a poor prognosis and was significantly associated with the N-stage in BC. ROC curves indicated that SNF5 could distinguish BC from the normal tissues. In vitro and in vivo functional assays demonstrated that attenuated SNF5 expression could promote cell proliferation and enhance migration by STAT3 activation. We imputed that low SNF5 expression could confer greater resistance against conventional first-line drugs, including cisplatin and gemcitabine in BC. GDSC and drug-resistance assays suggested that low SNF5 expression renders T24 and 5637 cells high sensitivity to EGFR inhibitor gefitinib, and combination of EZH2 Inhibitor GSK126 and cisplatin.

Conclusions: To the best of our knowledge, the present study, for the first time, showed that low SNF5 expression could promote cell proliferation and migration by activating STAT3 and confer poor prognosis in BC. Importantly, SNF5 expression may be a promising candidate for identifying BC patients who could benefit from EGFR-targeted chemotherapy or cisplatin in combination with EZH2 Inhibitor treatment regimens.