SWI/SNF related, matrix associated, actin-dependent regulator of chromatin, subfamily a, member 4 (SMARCA4, also known as BRG1), an ATPase subunit of the switch/sucrose non-fermentable (SWI/SNF) chromatin remodeling complex, plays an important regulatory role in many cytogenetic and cytological processes during cancer development. However, the biological function and mechanism of SMARCA4 in oral squamous cell carcinoma (OSCC) remain unclear. The present study aimed to investigate the role of SMARCA4 in OSCC and its potential mechanism. Using a tissue microarray, SMARCA4 expression was found to be highly upregulated in OSCC tissues. In addition, SMARCA4 upregulate expression led to increased migration and invasion of OSCC cells in vitro, as well as tumor growth and invasion in vivo. These events were associated with the promotion of epithelial–mesenchymal transition (EMT). Bioinformatic analysis and luciferase reporter assay confirmed that SMARCA4 is a target gene of microRNA miR-199a-5p. Further mechanistic studies showed that the miR-199a-5p regulated SMARCA4 can promote the invasion and metastasis of tumor cells through EMT. These findings indicate that the miR-199a-5p- SMARCA4 axis plays a role in tumorigenesis by promoting OSCC cell invasion and metastasis through EMT regulation. Our findings provide insights into the role of SMARCA4 in OSCC and the mechanism involved, which may have important implications for therapeutic purposes.

Environmental waters are an important reservoir for Vibrio cholerae , and effective surveillance of the pathogen can help to warn of and prevent infection with this potentially fatal pathogen. An immunofluorescent-aggregation (IFAG) assay to detect V. cholerae O1 and O139 was established and evaluated with estuarine water samples. The practical application of this assay was compared with the conventional culture method and real-time PCR. The IFAG method had a sensitivity of 10 ³ CFU/ml for detection of V. cholerae O1 and O139 strains in a suspension containing 10 different species of enterobacterial strains (total, 10 ⁵ CFU/ml). Ten fluorescent bacterial aggregate colonies were randomly picked and tested positive in serum agglutination tests for the V. cholerae O1 and O139 strains, showing a high specificity. The enrichment broths of 146 samples of estuarine water were tested, and the percentage positive by the IFAG assay was 19.9% (29/146), which was significantly higher than that of the conventional culture method (10.3%, 15/146; P < 0.01) but lower than that of real-time PCR (29.5%, 43/146; P < 0.01). The coincidence rates of real-time PCR and IFAG detection were decreased with the reduction of the V. cholerae concentration. The IFAG method, with a high specificity and a relatively high sensitivity, may be used for detection and isolation of V. cholerae in environmental water samples.

Serum response factor (SRF) regulates pro-carcinogenic genes in various cancers, but its role in oral squamous cell carcinoma (OSCC) remains unclear. SRF expression in 70 OSCC samples was detected via immunohistochemistry. Abundant SRF expressed in OSCC tissues was closely associated with tumor metastasis. SRF-overexpressing OSCC cells were constructed to evaluate how SRF affects OSCC cell tumorigenesis and epithelial-to-mesenchymal transition (EMT) in vitro and in vivo. Overexpressed SRF increased OSCC cell migration and invasion in vitro and tumor growth and invasion in vivo. This promoted EMT, characterized by decreased and increased expression of E- and N-cadherin, respectively. Furthermore, an analysis of RNA sequences of transcriptional targets of SRF showed that SRF transactivated the indoleamine 2, 3-dioxygenase 1 (IDO1)/kynurenine-aryl hydrocarbon receptor (Kyn-AhR) signaling pathway in OSCC cell lines. Direct SRF binding to the IDO1 gene promoter upregulated transcription, which was detected through chromatin immunoprecipitation and dual luciferase reporter assays. Inhibiting IDO1 or AhR impaired SRF-induced migration and invasion and prevented EMT in OSCC cells. Our results demonstrated that SRF is a critical regulator of the IDO1/Kyn-AhR signaling pathway. This in turn increases OSCC cell migration and invasion by modulating EMT, which, consequently, favors OSCC cell growth and metastasis. We revealed a novel molecular mechanism through which SRF modulates OSCC metastasis. This should provide potential targets or biomarkers for OSCC diagnosis and treatment.