Recent studies have revealed abnormal expression of miRNAs in various tumors. Although microRNA-338-3p (miR-338-3p) plays an important role in many types of tumors, its influence on liver cancer (LC) is unknown. In this study, we found that expression of miR-338-3p was decreased in LC cells and tissues. Colony formation and cell proliferation were suppressed by enhanced expression of miR-338-3p in LC cells. Moreover, miR-338-3p targeted sphingosine kinase 2 (SphK2). Silencing of SphK2 had an identical influence as overexpression of miR-338-3p in LC cells. Overexpression of SphK2 without the 3'-untranslated region remarkably enhanced the growth suppression triggered by miR-338-3p in LC cells. These findings indicate that miR-338-3p influences the development of LC by targeting SphK2, suggesting that miR-338-3p can be targeted as an innovative therapeutic strategy for LC.

Background and purpose: Gastric cancer is a type of highly heterogeneous malignant tumor and the prognosis of gastric cancer is hard to be improved due to limited knowledge on the molecular mechanism of heterogeneity. Single-cell sequencing technology is recently widely used for the investigation of both inter-tumoral heterogeneity and intra-tumoral heterogeneity. The present study aims to explore the potential oncogene by analyzing the single-cell data in the GSE167297 dataset.Methods: The GSE167297 dataset was downloaded from the GEO database, followed by quality control to remove data with lower quality. The division on cell subtypes was determined by the characteristic marker expressed in each cell subpopulation. Wilcoxon rank-sum test was used to screen out differentially expressed genes. Survival analysis was performed to evaluate the prognostic value of G-protein subunit g 11 (GNG11) gene which was significantly overexpressed in deep tumor tissues of diffuse gastric cancer.Results: In both normal tissues and tumor tissues, subtypes of immune cells and stromal cells were identified, with a higher proportion of infiltrated macrophages observed in deep tumor tissues. EPCAM was found significantly highly expressed in a cell subpopulation from gastric tumor tissues. 515 differentially expressed genes (| log2FC | > 2 and FDR < 1e-5) were screened out between normal tissues and tumor tissues. 86 differentially expressed genes (| log2FC | > 1 and FDR < 0.01) were screened out between superficial and deep tumor tissues, in which GNG11 was most highly expressed in deep tumor tissues (mean expression value: 0.1247, FC value: 52.2109). Disease-specific survival analysis on GNG11 results showed that the HR [95%CI] in the constructed univariate Cox proportional risk model was 4.419 [1.399-13.96] and the P-value in the log-rank test was 0.0056.Conclusion: Differentially expression profiles were provided both extratumorally and intratumorally, indicating a higher infiltration of macrophages in deep tumor tissues. Additionally,GNG11 was screened out to be a significant risk factor in STAD patients.