Methylation-driven genes and their prognostic value in cervical squamous cell carcinoma
ANNALS OF TRANSLATIONAL MEDICINE
Authors: Liu, Jinhui; Nie, Sipei; Li, Siyue; Meng, Huangyang; Sun, Rui; Yang, Jing; Cheng, Wenjun
Abstract
Background: Abnormal gene methylation is crucial for tumor progression. This study explored a cluster of methylation-driven genes involved in cervical squamous cell carcinoma (CESC). Methods: The data on RNA expression, methylation and clinical outcomes of CESC patients were downloaded from The Cancer Genome Atlas (TCGA) database. Protein-protein interaction (PPI) network was constructed. Gene Ontology (GO) and KEGG analyses were performed to identify the biological functions of methylation-driven genes, and univariable and multivariate Cox analyses to screen out the key prognostic genes. A risk signature was established and its predictive value was evaluated with Kaplan-Meier and ROC curves. The key genes were further investigated by Cox regression analyses, gene set enrichment analysis (GSEA), and methylation site analysis. Additionally, "rms" package was used for establishing nomogram and calibrate curve. Results: We found 144 differentially expressed methylation-driven genes. A risk model was constructed with three key prognostic genes (ITGA5, HHEX and S1PR4). The risk score was an independent risk factor for CESC prognosis. Lowly-expressed and hypermethylated ITGA5, highly-expressed and hypomethylated HHEX and S1PR4 were associated with better CESC prognosis. The methylation sites and biological functions enriched in ITGA5, HHEX and S1PR4 were uncovered. Additionally, the nomogram also validated the performance of risk model. Conclusions: Methylation-driven ITGA5, HHEX and S1PR4 are associated with CESC development. The three genes might serve as potential targets in the treatment of CESC.
Enhancement of RANKL-induced MITF-E expression and osteoclastogenesis by TGF-beta
CELL BIOCHEMISTRY AND FUNCTION
Authors: Asai, Kumiko; Funaba, Masayuki; Murakami, Masaru
Abstract
Microphthalmia-associated transcription factor (MITF) is a transcription factor that is expressed in limited types of cells, including osteoclasts, but the expression and role of MITF during osteoclastogenesis have not been fully elucidated. The expression of the MITF-E isoform but not that of the MITF-A isoform was induced in response to differentiation stimulation towards osteoclasts by receptor activator of NF-kappa B ligand (RANKL) in both RAW264.7 cells and primary bone marrow cells. The RANKL-induced formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells was inhibited in RAW264.7 cells expressing siRNA for MITF-E. Transforming growth factor-beta (TGF-beta) enhanced RANKL-induced MITF-E expression and - TRAP positive multinucleated cell formation. In particular, TGF-beta potentiated the formation of larger osteoclasts. The expression levels of NFATc1, TRAP and CtsK, genes related to osteoclast development and activity, were concurrently enhanced by TGF-beta in the presence of RANKL. Furthermore, the expression of dendritic cell-specific transmembrane protein (DC-STAMP), Itgav, Itga2, Itga5, Itgb1, Itgb3 and Itgb5, genes related to cell adhesion and fusion, were up-regulated by co-treatment with TGF-beta. In particular, the regulatory expression of Itgav and Itgb5 in response to RANKL with or without TGF-beta resembled that of MITF-E. Because MITF is involved in cell fusion in some cell systems, these results imply a role for MITF-E as an enhancer of osteoclastogenesis and that RANKL-induced levels of both MITF-E mRNA and of MITF-dependent gene expression are enhanced by treatment with TGF-beta. Copyright (C) 2014 John Wiley & Sons, Ltd.