RESUMO
Background: Because stomach adenocarcinoma (STAD) has a poor prognosis, it is necessary to explore new prognostic genes to stratify patients to guide existing individualized treatments. Methods: Survival and clinical information, RNA-seq data and mutation data of STAD were acquired from The Cancer Genome Atlas (TCGA) database. Fifty-one nicotinamide adenine dinucleotide (NAD+) metabolism-related genes (NMRGs) were obtained from the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Reactome databases. Differentially expressed NMRGs (DE-NMRGs) between STAD and normal samples were screened, and consistent clustering analysis of STAD patients was performed based on the DE-NMRGs. Survival analysis, Gene Set Enrichment Analysis (GSEA), mutation frequency analysis, immune microenvironment analysis and drug prediction were performed among different clusters. Additionally, the differentially expressed genes (DEGs) among different clusters were selected, and the intersections of DEGs and DE-NMRGs were selected as the prognostic genes. Finally, quantitative real-time polymerase chain reaction (qRT-PCR) was performed on a human gastric mucosa epithelial cell line and cancer cell line to verify the expression of the prognostic genes. Results: A total of 27 DE-NMRGs and two clusters were selected. There was a difference in survival between clusters 1 and 2. Furthermore, 18 DE-NMRGs were significantly different between clusters 1 and 2. The different Gene Ontology (GO) biological processes and KEGG pathways between clusters 1 and 2 were mainly enriched in cyclic nucleotide mediated signaling, synaptic signaling and hedgehog signaling pathway, etc. The somatic mutation frequencies were different between the two clusters, and TTN was the highest mutated gene in the patients of the clusters 1 and 2. Additionally, eight immune cells, immune score, stromal score, and estimate score were different between clusters 1 and 2. The patients in cluster 2 were sensitive to CTLA4 inhibitor treatment. Furthermore, the top five drugs (AP.24534, BX.795, Midostaurin, WO2009093927 and CCT007093) were significantly higher in cluster 1 than in cluster 2. Finally, three genes (AOX1, NNMT and PTGIS) were acquired as prognostic, and their expressions were consistent with the results of bioinformatics analysis. Conclusions: Three prognostic genes related to NAD+ metabolism in STAD were screened out, which provides a theoretical basis and reference value for future treatment and prognosis of STAD.
RESUMO
Hippo signaling pathway is an evolutionarily conserved developmental network that governs the downstream transcriptional co-activators, YAP and TAZ, which bind to and activate the output of TEADs that responsible for cell proliferation, apoptosis, and stem cell self renewal. Emerging evidence has shown the tumor suppressor properties of Hippo signaling. However, limited knowledge is available concerning the downstream transcription factors of Hippo pathway in osteosarcoma (OS). In this study, we demonstrated that TEAD1 was the major transcription factor of Hippo signaling pathway in OS. Genetic silencing of TEAD1 suppressed multiple malignant phenotypes of OS cells including cell proliferation, apoptosis resistance, and invasive potential. Mechanistically, we showed that TEAD1 largely exerted its transcriptional control of its functional targets, PTGS2 and CYR61. Collectively, this work identifies the YAP1/TEAD1 complex as the representative dysregulated profile of Hippo signaling in OS and provides proof-of-principle that targeting TEAD1 may be a therapeutic strategy of osteosarcoma.