Genomic landscape analyses in cervical carcinoma and consequences for treatment

Identification of a necroptosis-related prognostic gene signature associated with tumor immune microenvironment in cervical carcinoma and experimental verification

Cervical carcinoma (CC) has been associated with high morbidity, poor prognosis, and high intratumor heterogeneity. Necroptosis is the significant cellular signal pathway in tumors which may overcome tumor cells’ apoptosis resistance. To investigate the relationship between CC and necroptosis, we established a prognostic model based on necroptosis-related genes for predicting the overall survival (OS) of CC patients. The gene expression data and clinical information of cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) patients were obtained from The Cancer Genome Atlas (TCGA). We identified 43 differentially expressed necroptosis-related genes (NRGs) in CESC by examining differential gene expression between CESC tumors and normal tissues, and 159 NRGs from the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Gene ontology (GO) and KEGG enrichment analysis illustrated that the genes identified were mainly related to cell necrosis, extrinsic apoptosis, Influenza A, I − kappaB kinase/NF − kappaB, NOD − like receptor, and other signaling pathways. Subsequently, least absolute shrinkage and selection operator (LASSO) regression and univariate and multivariate Cox regression analyses were used to screen for NRGs that were correlated with patient prognosis. A prognostic signature that includes CAMK2A, CYBB, IL1A, IL1B, SLC25A5, and TICAM2 was established. Based on the prognostic model, patients were stratified into either the high-risk or low-risk subgroups with distinct survival. Receiver operating characteristic (ROC) curve analysis was used to identify the predictive accuracy of the model. In relation to different clinical variables, stratification analyses were performed to demonstrate the associations between the expression levels of the six identified NRGs and the clinical variables in CESC. Immunohistochemical (IHC) validation experiments explored abnormal expressions of these six NRGs in CESC. We also explored the relationship between risk score of this necroptosis signature and expression levels of some driver genes in TCGA CESC database and Gene Expression Omnibus (GEO) datasets. Significant relationships between the six prognostic NRGs and immune-cell infiltration, chemokines, tumor mutation burden (TMB), microsatellite instability (MSI), and immune checkpoints in CESC were discovered. In conclusion, we successfully constructed and validated a novel NRG signature for predicting the prognosis of CC patients and might also play a crucial role in the progression and immune microenvironment in CC.

Silencing of ITGB6 inhibits the progression of cervical carcinoma via regulating JAK/STAT3 signaling pathway

Background

Integrin β6 (ITGB6), a key submonomer of integrin αvβ6, plays an important role in epithelial-to-mesenchymal transition (EMT), wound healing, epithelial-derived tumor growth, fibrosis, and epithelial repair. However, the role of ITGB6 in cervical carcinoma (CC) remains elusive.

Methods

The expression levels of ITGB6 in CC tissues and cell lines were determined using quantitative real-time polymerase chain reaction (qRT-PCR). The cell viability, proliferation, apoptosis, migration, and invasion were evaluated by Cell Counting Kit-8 (CCK-8), colony-forming, flow cytometry, and Transwell assay, respectively. The expression of related proteins, including EMT markers and the Janus kinase/signal transducer and activator of transcription (JAK/STAT3) signaling markers, were detected using western blotting.

Results

The ITGB6 expression in CC tissues and cells (C-33A, Hela, SiHa, and Caski) was remarkably higher than that in paracarcinoma tissues and ECT1/E6E7 cells. The data from The Cancer Genome Atlas (TCGA) data set suggested that patients with CC with high ITGB6 expression showed poorer overall survival (OS). Compared with the empty transfection group (si-NC), si-ITGB6 restrained the proliferation, migration, and invasion of SiHa and Hela cells, while promoting cell apoptosis. si-ITGB6 suppression decreased the expression of Snail, vimentin, and N-cadherin, while increasing E-cadherin expression. Further research showed that si-ITGB6 reduced p-JAK1/JAK1, p-JAK2/JAK2, and p-STAT3/STAT3 expression in the JAK/STAT3 signaling pathway. Interestingly, proliferation, migration, invasion, and the expressions of the molecular markers of the JAK/STAT3 signaling pathway and EMT pathway induced by ITGB6 were altered by RO8191 (JAK/STAT3 pathway activator). Furthermore, the protein expression levels of Snail, vimentin, N-cadherin, p-STAT3/STAT3, p-JAK1/JAK1, and p-JAK2/JAK2 in tumor tissues were higher than those in adjacent normal tissue, while the expression level of E-cadherin was downregulated in tumor tissues.

Conclusions

Silencing of ITGB6 restrains cell proliferation, migration and invasion, and promotes apoptosis in CC by inhibiting JAK/STAT signaling pathways. Thus, ITGB6 may perhaps be a new and useful candidate target for treating CC.