Immune Infiltration and Clinical Outcome of Super-Enhancer-Associated lncRNAs in Stomach Adenocarcinoma.

Super-enhancers (SEs) comprise large clusters of enhancers that highly enhance gene expression. Long non-coding RNAs (lncRNAs) tend to be dysregulated in cases of stomach adenocarcinoma (STAD) and are vital for balancing tumor immunity. However, whether SE-associated lncRNAs play a role in the immune infiltration of STAD remains unknown. In the present study, we identified SE-associated lncRNAs in the H3K27ac ChIP-seq datasets from 11 tumor tissues and two cell lines. We found that the significantly dysregulated SE-associated lncRNAs were strongly correlated with immune cell infiltration through the application of six algorithms (ImmuncellAI, CIBERSORT, EPIC, quantiSeq, TIMER, and xCELL), as well as immunomodulators and chemokines. We found that the expression of SE-associated lncRNA TM4SF1-AS1 was negatively correlated with the proportion of CD8+ T cells present in STAD. TM4SF1-AS1 suppresses T cell-mediated immune killing function and predicts immune response to anti-PD1 therapy. ChIP-seq, Hi-C and luciferase assay results verified that TM4SF1-AS1 was regulated by its super-enhancer. RNA-seq data showed that TM4SF1-AS1 is involved in immune and cancer-related processes or pathways. In conclusion, SE-associated lncRNAs are involved in the tumor immune microenvironment and act as indicators of clinical outcomes in STAD. This study highlights the importance of SE-associated lncRNAs in the immune regulation of STAD.

Ferroptosis in Carcinoma: Regulatory Mechanisms and New Method for Cancer Therapy.

Ferroptosis is a new form of programmed cell death with characteristic accumulation of reactive oxygen species (ROS) resulting from iron accumulation and lipid peroxidation. Ferroptosis is involved in many diseases, including cancer, and induction of ferroptosis has shown attractive antitumour activities. In this review, we summarize recent findings on the regulatory mechanisms of key regulators of ferroptosis, including the catalytic subunit solute carrier family 7 member 11 (SLC7A11), the glutathione peroxidase 4 (GPX4), p53 and non-coding RNAs, the correlations between ferroptosis and iron homeostasis or autophagy, ferroptosis-inducing agents and nanomaterials and the diagnostic and prognostic value of ferroptosis-associated genes in TCGA data.

miR-125b-5p functions as a tumor suppressor gene partially by regulating HMGA2 in esophageal squamous cell carcinoma.

MicroRNAs (miRNAs) play important roles in the progression of human cancer including esophageal squamous cell carcinoma (ESCC). Although previous reports showed that miR-125b-5p was down-regulated in ESCC, the roles and mechanisms of loss of function of miR-125b-5p in ESCC were still unknown. Using microRNA microarray and GEO datasets, we found and confirmed that miR-125b-5p was down-regulated in ESCC tissues. In-vitro assays showed that ectopic miR-125b-5p expression repressed cell proliferation, migration and invasion, and induced cell senescence. We also found that miR-125b-5p reduced the expressions of cell cycle regulatory genes including CCNA2, CCND1 and CCNE1, and regulated the markers of epithelial to mesenchymal transition (EMT) including E-cadherin, N-cadherin and EMT associated transcription factor Slug, and also decreased the MMPs including MMP2, MMP7 and MMP13. Furthermore, the candidate target gene HMGA2 was negatively regulated by miR-125b-5p both in mRNA and protein levels. Importantly, knockdown of HMGA2 partially phenocopied the effects of miR-125b-5p overexpression on cell cycle regulators and EMT markers. In conclusion, our results suggested that overexpression of miR-125b-5p inhibited cell proliferation, migration and invasion partially by down-regulating HMGA2 in ESCC.

miR-145-5p Suppresses Tumor Cell Migration, Invasion and Epithelial to Mesenchymal Transition by Regulating the Sp1/NF-κB Signaling Pathway in Esophageal Squamous Cell Carcinoma.

MicroRNAs (miRNAs) play important roles in the progression of human cancer. Although previous reports have shown that miR-145-5p is down-regulated in esophageal squamous cell carcinoma (ESCC), the roles and mechanisms of down-regulation of miR-145-5p in ESCC are still largely unknown. Using microRNA microarray and Gene Expression Omnibus (GEO) datasets, we confirmed that miR-145-5p was down-regulated in ESCC tissues. In vitro assays revealed that ectopic miR-145-5p expression repressed cell proliferation, migration, invasion and epithelial to mesenchymal transition (EMT). miR-145-5p also reduced the expressions of cell cycle genes including cyclin A2 (CCNA2), cyclin D1 (CCND1) and cyclin E1 (CCNE1), the EMT-associated transcription factor Slug, and matrix metalloproteinases (MMPs) including MMP2, MMP7 and MMP13. Furthermore, miR-145-5p mimics reduced candidate target gene specificity protein 1 (Sp1) and nuclear factor κ B (NF-κB) (p65) both in mRNA and protein levels. Knockdown of Sp1 phenocopied the effects of miR-145-5p overexpression on cell cycle regulators, EMT and the expression of NF-κB (p65). Importantly, inhibition of the NF-κB signaling pathway or knockdown of NF-κB (p65) phenocopied the effects of miR-145-5p on the migration, invasion and EMT of ESCC cells. In conclusion, our results suggested that miR-145-5p plays tumor-suppressive roles by inhibiting esophageal cancer cell migration, invasion and EMT through regulating the Sp1/NF-κB signaling pathway.

MiR-99a suppresses proliferation, migration and invasion of esophageal squamous cell carcinoma cells through inhibiting the IGF1R signaling pathway.

miR-99a is down-regulated in esophageal squamous cell carcinoma (ESCC), however the role and underlying mechanism are still unknown. We aim to explore the role and mechanism of miR-99a down-regulation in ESCC. The expression of miR-99a in ESCC tissues and cell lines was detected by Human miRNA Microarrays and Real-time PCR. The effects of miR-99a on cell proliferation, migration and invasion were determined by Cell Counting Kit-8 (CCK-8) assay, transwell migration and invasion assay. Target gene of miR-99a were analyzed by target prediction software and validated by Real-time PCR and Western blotting assay. Our microarray results and four Gene Expression Omnibus (GEO) datasets showed lower expression level of miR-99a in ESCC tissues. Overexpression of miR-99a using mimics significantly suppressed cell proliferation, and decreased expressions of CCND1, CCNA2 and CCNE1. We also found that enhanced miR-99a significantly inhibited migration, invasion and epithelial-mesenchymal transition (EMT) of ESCC cells, and down-regulated EMT associated transcription factor Slug, and MMPs including MMP2, MMP7 and MMP13. TargetScan predicted insulin-like growth factor 1 receptor (IGF1R) as the cadidate target gene of miR-99a, and western blotting confirmed the negative correlation between miR-99a and IGF1R. Importantly, we further found that knockdown of IGF1R also significantly inhibited the proliferation, migration, invasion and slug-induced EMT of ESCC cells, and reduced the cell cycle regulatory proteins and MMPs. In conclusion, our findings suggested that loss of miR-99a in ESCC promoted the tumor cell proliferation, migration, invasion and slug-induced EMT through activating IGF1R signaling pathway.

MCM7 amplification and overexpression promote cell proliferation, colony formation and migration in esophageal squamous cell carcinoma by activating the AKT1/mTOR signaling pathway.

The roles and mechanisms of mini-chromosome maintenance complex component 7 (MCM7) amplification and overexpression in esophageal carcinogenesis were investigated. By analyzing the TCGA datasets, we found that MCM7 was amplified in approximately 12% of esophageal squamous cell carcinomas (ESCCs), and in more than 4% of head and neck squamous cell carcinomas and stomach carcinomas. Overexpression of MCM7 was further verified in three independent GEO datasets of esophageal cancer. Knockdown of MCM7 using two siRNAs significantly inhibited cell proliferation, colony formation and migration of KYSE510 and EC9706 cells in vitro. Noteworthy, we further found that silencing of MCM7 suppressed the phosphorylation of AKT1 and mTOR both in KYSE510 and EC9706 cells, and reduced the cell cycle regulatory proteins cyclin D1, cyclin E2 and CDK2. Taken together, our findings suggested that MCM7 promoted tumor cell proliferation, colony formation and migration of ESCC cells via activating AKT1/mTOR signaling pathway.

MicroRNAs in esophageal squamous cell carcinoma: Potential biomarkers and therapeutic targets.

Esophageal cancer is a common cause of cancer-related deaths worldwide. Squamous cell carcinoma (SCC) is the major histological type of esophageal cancer in developing countries including China, and the prognosis is very poor. Many microRNAs are involved in several important biological and pathologic processes, and promote tumorigenesis. To better understand the prognostic and therapeutic roles of microRNAs in ESCC, we reviewed the diagnosis and prognosis associated oncogenic microRNAs (e.g. miR-21 and miR-17-92 cluster) and tumor suppressor microRNAs (e.g. miR-375, miR-133a and miR-133b), and diagnosis and prognosis associated oncogenic target genes (e.g. PDCD4 and CCND1) and tumor suppressor target genes (e.g. EZH2 and PDK1). We also summarized the prognostic microRNA and target gene pairs (e.g. miR-296 and CCND1, miR214 and EZH2). Taken together, our review highlights the opportunities and challenges for microRNAs in the molecular diagnosis and target therapy of ESCC.

Overexpression of microRNA-1470 promotes proliferation and migration, and inhibits senescence of esophageal squamous carcinoma cells.

MicroRNA-1470 (miR-1470) is overexpressed in esophageal squamous cell carcinoma (ESCC); however, its role and underlying molecular mechanism remain unknown. The aim of the present study was to explore the tumorigenic role and mechanism of miR-1470 overexpression in ESCC. The expression of miR-1470 in ESCC tissues and cell lines was detected using human miRNA microarrays and the reverse transcription-quantitative polymerase chain reaction, respectively. The effects of miR-1470 on cell proliferation, migration and senescence were determined using a Cell Counting Kit-8 assay, Transwell migration assay and ß-galactosidase staining kit. Western blotting was used to analyze the expression levels of genes in the apoptosis signaling pathway. An increased expression level of miR-1470 was observed in ESCC tissues compared with that in paracancerous tissues. Knockdown of miR-1470 significantly suppressed proliferation, and down-regulated the cell cycle regulatory gene cyclin E1. It was also revealed that knockdown of miR-1470 significantly inhibited migration, and decreased the expression levels of matrix metalloproteinase 2 (MMP2), MMP13 and MMP14. Western blotting analysis revealed that knockdown of miR-1470 induced apoptosis by increasing B-cell lymphoma 2 (Bcl-2) expression. The results of the present study suggest that overexpression of miR-1470 in ESCC promotes cancer cell proliferation by accelerating the cell cycle and inhibiting apoptosis, and also enhances cancer cell migration by upregulating MMPs.

Identification of candidate target genes of genomic aberrations in esophageal squamous cell carcinoma.

The aim of the present study was to identify the candidate target genes of genomic aberrations in esophageal squamous cell carcinoma (ESCC). Array comparative genomic hybridization (CGH) and quantitative polymerase chain reaction were applied to analyze the copy number changes and expression level of candidate genes, respectively. Integrative analysis revealed that homozygous deletions of cyclin-dependent kinase inhibitor (CDKN) 2A and CDKN2B and gains of fascin actin-bundling protein 1 (FSCN1) and homer scaffolding protein 3 (HOMER3) occurred frequently in ESCC. The results demonstrated that the homozygous deletion of CDKN2A or CDKN2B was significantly associated with lymph node metastasis. Notably, the expression of CDKN2A and CDKN2B was lower in dysplasia than in normal esophageal epithelium. We also observed that the copy number increase of FSCN1 was significantly associated with pT, pN and pStage, and that the gain of HOMER3 was significantly linked with pN and pStage. We further revealed that FSCN1 and HOMER3 were overexpressed in ESCC, and that their overexpression was correlated with copy number increase. In conclusion, CDKN2A, CDKN2B, FSCN1 and HOMER3 are candidate cancer-associated genes and may play a tumorigenic role in ESCC.