LncRNA HOXC-AS1 Sponges miR-99a-3p and Upregulates MMP8, Ultimately Promoting Gastric Cancer

MicroRNA-99 family in cancer: molecular mechanisms for clinical applications

MicroRNAs (miRNAs) are a class of non-coding RNA sequences that regulate gene expression post-transcriptionally. The miR-99 family, which is highly evolutionarily conserved, comprises three homologs: miR-99a, miR-99b, and miR-100. Its members are under-expressed in most cancerous tissues, suggesting their cancer-repressing properties in multiple cancers; however, in some contexts, they also promote malignant lesion progression. MiR-99 family members target numerous genes involved in various tumor-related processes such as tumorigenesis, proliferation, cell-cycle regulation, apoptosis, invasion, and metastasis. We review the recent research on this family, summarize its implications in cancer, and explore its potential as a biomarker and cancer therapeutic target. This review contributes to the clinical translation of the miR-99 family members.

HOXC-AS1 and EZH2 interaction increase HOXC9 expression and promote the malignant transformation of oral leukoplakia

Objective: To investigate the role of HOXC9 in the transformation of oral leukoplakia (OLK) to oral squamous cell carcinoma (OSCC) and its effectiveness as a new molecular marker for oral leukoplakia carcinogenesis. Materials and Methods: We assessed HOXC9 in OLK and OSCC using immunohistochemistry (IHC). Colony formation and transwell experiment were employed to appraise the function of HOXC9 in the malignant transformation of OLK. ChIP-qPCR, CO-IP, RIP-qPCR, RNA pull down and mass spectrometry were using to evaluate the molecular mechanism of HOXC9. Results: HOXC9 expression was higher in patients with OSCC than in those with OLK, which is associated with increased malignant transformation of OLK. Functional experiments suggested that HOXC9 induces the acquisition of cancer stem cells (CSCs) and epithelial-to-mesenchymal transition (EMT). Subsequently, we found that the HOXC9-mediated malignant phenotype was reversed by HOXC-AS1 depletion. Mechanistically, HOXC-AS1 regulates H3K27me3 methylation and EZH2 as a potential HOXC-AS1-HOXC9 interacting protein. Finally, we found that the 251-619nt nucleotide of HOXC-AS1 competitively binds to EZH2. Conclusion: HOXC-AS1 competitively binds to EZH2, inhibiting its binding to H3 in the HOXC9 promoter region, resulting in a decrease in H3K27me3 and enhanced expression of HOXC9, thereby promoting CSCs and EMT in oral leukoplakia, ultimately leading to malignant transformation into oral squamous cell carcinoma.

Bioinformatics analysis identifies coagulation factor II receptor as a potential biomarker in stomach adenocarcinoma

Coagulation factor 2 thrombin receptor (F2R), a member of the G protein-coupled receptor family, plays an important role in regulating blood clotting through protein hydrolytic cleavage mediated receptor activation. However, the underlying biological mechanisms by which F2R affects the development of gastric adenocarcinoma are not fully understood. This study aimed to systematically analyze the role of F2R in gastric adenocarcinoma. Stomach adenocarcinoma (STAD)-related gene microarray data and corresponding clinicopathological information were downloaded from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Differential expression genes (DEGs) associated with F2R were analyzed using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), gene set enrichment analysis (GSEA), and protein-protein interaction (PPI) networks. F2R mRNA expression data were utilized to estimate stromal cell and immune cell scores in gastric cancer tissue samples, including stromal score, immune score, and ESTIMATE score, derived from single-sample enrichment studies. Analysis of TCGA and GEO databases revealed significantly higher F2R expression in STAD tissues compared to normal tissues. Patients with high F2R expression had shorter survival times than those with low F2R expression. F2R expression was significantly correlated with tumor (T) stage, node (N) stage, histological grade and pathological stage. Enrichment analysis of F2R-related genes showed that GO terms were mainly related to circulation-mediated human immune response, immunoglobulin, cell recognition and phagocytosis. KEGG analysis indicated associations to extracellular matrix (ECM) receptor interactions, neuroactive ligand-receptor interactions, the phosphoinositide-3-kinase-protein kinase B/Akt (PI3K-AKT) signaling pathway, the Wnt signaling pathway and the transforming growth factor-beta (TGF-β) signaling pathway. GSEA revealed connections to DNA replication, the Janus kinase/signal transducers and activators of transcription (JAK-STAT) signaling pathway, the mitogen-activated protein kinase (MAPK) signaling pathway and oxidative phosphorylation. Drug sensitivity analysis demonstrated positive correlations between F2R and several drugs, including BEZ235, CGP-60474, Dasatinib, HG-6-64-1, Aazopanib, Rapamycin, Sunitinib and TGX221, while negative correlation with CP724714, FH535, GSK1904529A, JNK-9L, LY317615, pyrimidine, rTRAIL and Vinorelbine. Knocking down F2R in GC cell lines resulted in slowed proliferation, migration, and invasion. All statistical analyses were performed using R software (version 4.2.1) and GraphPad Prism 9.0. p < 0.05 was considered statistically significant. In conclusion, this study underscores the significance of F2R as a potential biomarker in gastric adenocarcinoma, shedding light on its molecular mechanisms in tumorigenesis. F2R holds promise for aiding in the diagnosis, prognosis, and targeted therapy of STAD.

Integrated Bioinformatics and Experimental Analysis of Long Noncoding RNA Associated-ceRNA as Prognostic Biomarkers in Advanced Stomach Adenocarcinoma

BACKGROUND

Advanced stomach adenocarcinoma (ASTAD) is a highly malignant and prognostically poor stage of gastric cancer. Recently, long noncoding RNA (lncRNA) was found to play a crucial role, including as competing endogenous RNA (ceRNA) in cancer. However, studies on large-scale sample in ASTAD are still lacking, thus we constructed the ceRNA network of ASTAD to explore its molecular mechanism.

METHODS

We compared the expression of mRNAs, lncRNAs and miRNAs between ASTAD and normal tissues utilizing RNA-Seq and miRNA-seq Data from The Cancer Genome Atlas (TCGA). GO and KEGG enrichment analysis were executed for annotating the functions of differentially expressed mRNAs. Subsequently, we investigated the expression correlations between the differentially expressed lncRNAs and their respective mRNAs by constructing a ceRNA network. Kaplan-Meier survival analysis was used to assess the relationship between high/low risk scores based on this network with patient prognosis in TCGA training cohort and GSE15459 validation cohort. In vitro functional assays were employed to verify the cancer-promoting effects of key lncRNAs in the ceRNA network and their possible mechanisms.

RESULTS

In ASTAD tissues, a total of 176 lncRNAs, 124 miRNAs, and 2205 mRNAs were identified as differentially expressed. Our constructed ceRNA network consisted 6 differentially expressed lncRNAs (PVT1, MAGI2-AS3, KCNQ1OT1, LINC02086, AC125807.2 and LINC02535), 25 miRNAs and 130 mRNAs, and the risk score derived from these lincRNAs could predict ASTAD patient outcomes. Key lncRNA LINC02086 was experimentally verified to enhance proliferation and migration of gastric cancer cells by competitively binding to miR-93a-5p with MMP3.

CONCLUSION

Our comprehensive ceRNA network for ASTAD provides valuable insights into its molecular mechanisms, and LINC02086 may be used as an innovative target for clinical treatment.

Long non-coding RNA HOXC-AS1 exerts its oncogenic effects in esophageal squamous cell carcinoma by interaction with IGF2BP2 to stabilize SIRT1 expression

BACKGROUND

Long non-coding RNA HOXC cluster antisense RNA 1 (HOXC-AS1) is a novel lncRNA whose cancer-promoting effect in gastric cancer and nasopharyngeal carcinoma has already been demonstrated. However, its functions in esophageal squamous cell carcinoma (ESCC) remains unknown. LncRNAs can interact with RNA-binding proteins (RBPs) and affect gene expression levels through post-transcriptional regulation. Insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) is a widely studied RBP, and sirtuin 1 also known as SIRT1 has been reported to be involved in cancer progression.

METHODS

Establishment of in vivo models, HE and immunohistochemistry staining verified the oncogenic effect of HOXC-AS1. The interaction relationship between HOXC-AS1, IGF2BP2 and SIRT1 was verified by RNA pulldown and RNA immunoprecipitation (RIP) assay. Relative expression and stability changes of genes were detected by qPCR and actinomycin D experiments. Finally, the effect of HOXC-AS1-IGF2BP2-SIRT1 axis on ESCC was verified by rescue experiments.

RESULTS

HOXC-AS1 is highly expressed in ESCC cells and plays oncogenic effects in vivo. qPCR showed the positive relationship between HOXC-AS1 and SIRT1 following HOXC-AS1 knockdown or overexpression. RNA-pulldown, mass spectrometry and RIP assay demonstrated that IGF2BP2 is an RBP downstream of HOXC-AS1. Then, RIP and qPCR showed that IGF2BP2 could bind to SIRT1 mRNA and knockdown IGF2BP2 resulted in decreased SIRT1 mRNA level. Finally, a series of rescue assay showed that the HOXC-AS1-IGF2BP2-SIRT1 axis can affect the function of ESCC.

CONCLUSION

LncRNA HOXC-AS1 acts as an oncogenic role in ESCC, which impacts ESCC progression by interaction with IGF2BP2 to stabilize SIRT1 expression.