No abstract

Regulatory functions of circRNAs by targeting the micro RNA (miRNA)/mRNA axis have been increasingly found in oral squamous cell carcinoma (OSCC). CircRNA keratin 1 (CircKRT1) and miR‐495‐3p were dysregulated in OSCC. Programmed death ligand 1 (PDL1) was an important immunotherapeutic molecule in OSCC. Our objective was to explore whether circKRT1 could regulate cancer progression and immune evasion in OSCC by affecting the miR‐495‐3p/PDL1 axis. RNA expression was examined by quantitative real‐time polymerase chain reaction. All protein levels were detected by western blot. OSCC cell growth was assessed by CCK‐8 and colony formation assays. Cell migratory and invasive abilities were evaluated by transwell assay. CD8+ T‐cell cytotoxicity was determined via lactate dehydrogenase assay. CD8+ T‐cell percentage and apoptosis were analyzed by flow cytometry. Target screening was performed by Veen Diagram and RNA pull‐down assay. Target binding was verified using dual‐luciferase reporter and RNA immunoprecipitation assays. A xenograft in mice was conducted for in vivo experiment. CircKRT1 and PDL1 were highly expressed in OSCC tissues and cells. CircKRT1 knockdown repressed OSCC cell growth, migration, invasion, epithelial–mesenchymal transition, and CD8+ T‐cell apoptosis, but enhanced CD8+ T cytotoxicity and percentage. The inhibitory effects of circKRT1 downregulation on OSCC progression and immune evasion were related to PDL1 expression inhibition. CircKRT1 sponged miR‐495‐3p and miR‐495‐3p targeted PDL1. OSCC progression and immune evasion were regulated by circKRT1 via the miR‐495‐3p/PDL1 axis. CircKRT1 also facilitated OSCC progression in vivo by regulating miR‐495‐3p and PDL1. This study clarified that circKRT1 worked as a miR‐495‐3p sponge to regulate PDL1, consequently affecting cancer progression and immune evasion in OSCC.

Gastric cancer (GC) is one of the most widely occurring malignancies worldwide. Although the diagnosis and treatment strategies of GC have been greatly improved in the past few decades, the morbidity and lethality rates of GC are still rising due to lacking early diagnosis strategies and powerful treatments. In this study, a total of 37 differentially expressed genes were identified in GC by analyzing TCGA, GSE118897, GSE19826, and GSE54129. Using the PPI database, we identified 17 hub genes in GC. By analyzing the expression of hub genes and OS, MFAP2, BGN, and TREM1 were related to the prognosis of GC. In addition, our results showed that higher levels of BGN exhibited a significant correlation with shorter OS time in GC. Nomogram analysis showed that the dysregulation of BGN could predict the prognosis of GC. Moreover, we revealed that BGN had a markedly negative correlation with B cells but had positive correlations with CD8+ T cells, CD4+ T cells, macrophages, neutrophils, and dendritic cells in GC samples. The pan-cancer analysis demonstrated that BGN was differentially expressed and related to tumor-infiltrating immune cells across human cancers. This study for the first time comprehensively revealed that BGN was a potential biomarker for the prediction of GC prognosis and tumor immune infiltration.

Growing data have recognized the significance of Response Gene to Complement (RGC)-32 in numerous tumour developments. Notwithstanding, the functional role and underlying mechanism of it in tongue squamous cell carcinoma (TSCC) remain enigmatic. Here, to identify the impact of RGC-32 in TSCC, its expression in multiple TSCC cells was measured and loss-of-function experiments in cell lines were performed to illuminate the function of it induced TSCC progression, via si-RNA knockdown, CCK-8, colony formation, wound-healing, transwell, flow cytometry and western blot assays. To clarify potential mechanism, expressions of hallmarks in epithelial-mesenchymal transition (EMT) process and PI3K/AKT signalling were assessed, and the upstream miR regulator of RGC-32 was predicted and verified by applying bioinformatic approaches and dual-luciferase reporter assay, respectively. Finally, the rescue experiments were applied to better elucidate the effect of miR-26b/RGC-32 axis in TSCC behaviours. As a result, RGC-32 was upregulated in TSCC cells and knocking down of it abrogated cell proliferation, trans-migration and invasion, whilst promoted apoptosis in TSCC, which was regulated through repressing EMT and inactivation of PI3K/AKT signalling. Subsequently, miR-26b was predicted and identified as an upstream regulator of RGC-32, and the pro-tumorigenic effect of RGC-32 was reversed by miR-26b overexpression. Collectively, our results demonstrated that RGC-32 facilitated TSCC progression, which was modulated by activations of PI3K/AKT pathway and EMT process, and reduction of its negative regulator of miR-26b. These findings highlight a novel role of miR-26b/RGC-32 axis in TSCC and underlying mechanism, encouraging a potent usage in TSCC treatment. Significance of the study: We first uncovered that Response Gene to Complement-32 played a significantly pro-tumorigenic role in tongue squamous cell carcinoma (TSCC), which was closely regulated by downregulation of miR-26b and activations of epithelial-mesenchymal transition process and PI3K/AKT signalling. These findings contribute to better understand the molecular mechanism in carcinogenesis of TSCC, and shed some light on promising strategy for TSCC therapeutics.