Background: Liver cancer is among the most common malignancy worldwide. Hepatocellular carcinoma (HCC), the principal histological subtype of liver cancer, is globally the third most common cause of cancer-related mortality. The high rates of recurrence and metastasis contribute to the poor prognosis of HCC patients. In recent years, increasing evidence has shown that microRNAs (miRNAs) are involved in the tumorigenesis, progression, and prognosis of HCC. Methods: To screen for key candidate miRNAs in HCC, three microarray datasets were downloaded from Gene Expression Omnibus (GEO). The sole common differentially expressed miRNA (DEmiR) observed in the above three datasets using a Venn diagram was microRNA-211-5p (miR-211-5p). The expression of miR-211-5p from HCC tissues was measured in several HCC cell lines. Additionally, using Kaplan–Meier plots, the potential prognostic value of miR-211-5p in HCC was analyzed. Cell counting kit-8 (CCK-8) and transwell assays examined the ability of miR-211-5p to induce cell proliferation, migration, and invasion in HCC cultures. The interaction of miR-211-5p and Acyl-CoA Synthetase Long Chain Family Member 4 (ACSL4) was assessed both theoretically and using a luciferase reporter assay. Finally, the ability of miR-211-5p to modulate tumorigenesis in HCC in vivo was assessed after establishing a xenograft model. Results: qRT-PCR demonstrated that the relative expression of miR-211-5p was considerably down-regulated in HCC tissues and cell lines compared with normal tissue. Kaplan–Meier plots indicated that HCC patients with decreased expression of miR-211-5p had poor overall survival. Upregulation of miR-211-5p in vitro consistently suppressed cell proliferation, migration, and invasion. In contrast, enhanced expression of ACSL4 promoted a malignant phenotype in HCC cells. Importantly, we discovered that ACSL4 was a direct downstream target of miR-211-5p in HCC, and that miR-211-5p suppressed the malignant phenotype by inhibition of ACSL4 expression. Furthermore, miR-211-5p overexpression impaired tumorigenesis and growth of HCC in vivo. Conclusions: Targeting miR-211-5p and the downstream gene ACSL4 will possibly provide novel insight and represents a promising approach to future therapy of HCC patients.

The prognosis of CCA is extremely poor, making it one of the most lethal cancers. Therefore, there is a need to elucidate the pathogenic mechanisms of CCA. In this study, we aimed at identifying lncRNA-related prognostic signatures for CCA through bioinformatics analysis and further validated their functions in CCA tumorigenesis and progression. The RNA-seq data of CCA were downloaded from public databases. Differentially expressed lncRNAs (DElncRNAs) were screened. Then, candidate OS- and DFS-related DElncRNAs were selected through Kaplan-Meier survival analysis. Furthermore, LASSO regression was performed to establish the OS and DFS signatures, respectively. Multivariate COX models and nomograms for overall survival (OS) and disease-free survival (DFS) were established based on OS/DFS signature and clinical data. Hub lncRNAs were identified and enrichment analyses were performed to explore their potential functions. Finally, in vitro and in vivo models were used to validate the effects of the hub lncRNAs in CCA tumorigenesis and progression. A total of 925 DElncRNAs were selected, of which six candidate OS-related lncRNAs and 15 candidate DFS-related lncRNAs were identified. The OS and DFS signatures were then established using four lncRNAs, respectively. We found that the OS signature and vascular invasion were independent risk factors for the OS of CCA, while the DFS signature, vascular invasion, and CA19-9 were independent risk factors for the DFS of CCA. Then, nomograms were established to achieve personalized CCA recurrence and death prediction. Furthermore, our study uncovered that MIR4435-2HG and GAPLINC might play crucial roles in CCA progression and be selected as hub lncRNAs. GO and KEGG enrichment analyses revealed that the two hub lncRNAs were closely related to CCA tumorigenesis. Finally, we demonstrated that MIR4435-2HG and GAPLINC can stimulate CCA proliferation and migration in vitro and in vivo. The established OS and DFS signatures are independent risk factors for OS and DFS of CCA patients, respectively. MIR4435-2HG and GAPLINC were identified as hub lncRNAs. In vitro and in vivo models revealed that MIR4435-2HG and GAPLINC can prompt CCA progression, which might be novel prognostic biomarkers and therapeutic targets for CCA.

Background: N6-methyladenosine (m6A) RNA methylation regulators have been implicated in the carcinogenesis and progress of a variety of cancers. Until now, the effects of them on intrahepatic cholangiocarcinoma (ICC) have been poorly understood. Methods: We used the GEO databases to systematically evaluate the expression profiles of 36 m6A RNA methylation regulators in ICC patients and produced a signature to assess its prognostic values. In vitro experiments were implemented to confirm the expression level. Results: Compared to normal intrahepatic bile duct tissues, more than half of these 36 genes showed different levels of expression in ICC tissues. Two groups emerged from the consensus cluster analysis of these 36 genes. The two cluster of patients had significantly different clinical outcomes. In addition, we created a m6A-related prognostic signature that performed exceptionally well in the prognostic categorization of ICC patients, based on the ROC curves, Kaplan-Meier curves, and univariate and multivariate Cox regression analyses. Further research showed that there was a significant association between the m6A-related signature and the manifestations of tumor immune microenvironment in ICC. The expression level and biological effect of METTL16, one of the two m6A RNA methylation regulators incorporated in the signature, were confirmed and explored by using in vitro experiments. Conclusions: This analysis revealed the predictive roles of m6A RNA methylation regulators in ICC.

Aim: This study aimed to investigate the biological functions of miRNAs in hepatobiliary tumors as the focus of targeted therapy research. Background: Hepatobiliary tumors are among the leading causes of cancer-related deaths worldwide. Many microRNAs (miRNAs) play an important regulatory role in tumor progression. Our study aims to explore some biologically functional miRNAs from different datasets of hepatobiliary tumors for disease diagnosis or treatment. Objective: In this study, we tried to filter out differentially expressed miRNAs in different tumor datasets from the GEO database. Methods: In this study, we first perform analyses in different GEO data sets. After taking the intersection, the initial scope is limited to several differential RNAs. Then, combined with the existing research results from Kaplan-Meier survival analysis and literature, the candidate molecule was finally identified to be studied. Furthermore, the biological characteristics analysis of the candidate molecule was performed on the basis of Cancermirnome online tool, including expression levels in tumors, KEGG and GO analysis, ROC analysis, and target gene prediction. Furthermore, the effect of the candidate molecule on the biological functions of liver cancer was verified by in vitro assay. Results: The preliminary analysis of bioinformatics shows that 16 differentially expressed miRNAs may play an important role in HCC or ICC. Ultimately, we identified miRNA-99a-5p as the only molecule to study. The results showed that miRNA-99a-5p is abnormally expressed in many tumors, and in liver cancer, its level of expression in tumor tissue is significantly lower than that in normal tissue. Then, the KEGG and GO analysis found that it functions in multiple pathways. At the same time, the ROC analysis found that it showed great potential for prognostic prediction in HCC and we also predicted that RUNDC3B is the most likely target to which it binds. Finally, the experimental results of overexpression and knockdown confirmed that miRNA-99a-5p could inhibit cell proliferation in HCC, which also suggested that it may be an important tumor suppressor in HCC. Conclusion: MiRNA-99a-5p was negatively correlated with HCC progression and could act as a novel therapeutic target for HCC.