MicroRNA-370 functions as a tumor suppressor in hepatocellular carcinoma via inhibition of the MAPK/JNK signaling pathway by targeting BEX2

Cross-regulation between microRNAs and key proteins of signaling pathways in hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma (HCC) is a subtype of primary liver cancer and a major cause of death. Although miRNA plays an important role in hepatocellular carcinoma, the specific regulatory network remains unclear. Therefore, this paper comprehensively describes the miRNA-related signaling pathways in HCC and the possible interactions among different signaling pathways. The aim is to lay the foundation for the discovery of new molecular targets and multi-target therapy.

AREAS COVERED

Based on miRNA, HCC, and signaling pathways, the literature was searched on Web of Science and PubMed. Then, common targets between different signaling pathways were found from KEGG database, and possible cross-regulation mechanisms were further studied. In this review, we elaborated from two aspects, respectively, laying a foundation for studying the regulatory mechanism and potential targets of miRNA in HCC.

EXPERT OPINION

Non-coding RNAs have become notable molecules in cancer research in recent years, and many types of targeted drugs have emerged. From the outset, molecular targets and signal pathways are interlinked, which suggests that signal pathways and regulatory networks should be concerned in basic research, which also provides a strong direction for future mechanism research.

Bioinformatics Study Revealed Significance of Exosome Transcriptome in Hepatocellular Carcinoma Diagnosis

Background: Hepatocellular carcinoma (HCC) is one of the fifty most common cancers globally, having a high mortality rate being the second most common cause of cancer-related deaths. However, little attention has been paid to the involvement of exosomes and ceRNA in HCC.

Method: The study aimed to explore exosome data from exoRBase database and a free online database to estimate possible binding miRNA from mRNA, lncRNA, and circRNA and discover useful exosome biomarkers for HCC therapy.

Results: The results indicated that a total of 159 mRNAs, 60 lncRNAs, and 13 circRNAs were differentially expressed, with HIST2H3C exhibiting the highest log₂FC change, CTD-2031P19 exhibiting the most relevant lncRNA, and CTD-2031P19 exhibiting the most relevant lncRNA. MARCH8, SH3PXD2A, has-circ-0014088, hsa-miR-186-5p, and hsa-miR-613 were identified as hub biomarkers used by Cytoscape. According to the KEGG pathway analysis results, the differentially expressed proteins were primarily enriched in the MAPK signaling network, central carbon metabolism in cancer, the glucagon signaling pathway, glutamatergic synapse, and spliceosome. Furthermore, immunohistochemical images from the Human Protein Atlas (HPA) online tool were used to directly evaluate the protein expression of SMARCA5, CDC42, and UBC between normal and cancer tissues, and the results showed that these three gene expressions were significantly higher in tumor tissues.

Conclusion: This study discovered atypical signature exosomes for HCC prognostic prediction based on an online database. The signals could mimic exosome microenvironmental disorders providing potential biomarkers for exosome treatment.

MiR-20b-5p promotes hepatocellular carcinoma cell proliferation, migration and invasion by down-regulating CPEB3

INTRODUCTION AND OBJECTIVES

This study aimed to explore the functional mechanism of the miRNA-20b-5p/cytoplasmic polyadenylation element binding protein 3 (miR-20b-5p/CPEB3) axis in hepatocellular carcinoma (HCC) so as to provide a new idea for targeted therapy of HCC.

MATERIALS AND METHODS

Bioinformatics analysis was employed to obtain markedly differentially expressed miRNAs and mRNAs in The Cancer Genome Atlas-Liver Hepatocellular Carcinoma (TCGA-LIHC) dataset, so as to find target miRNA and its target mRNA. Real-time quantitative PCR was conducted to detect miR-20b-5p and CPEB3 mRNA expression. Western blot was performed to determine CPEB3 protein expression. Dual-luciferase reporter assay was carried out to verify the targeting relationship between miR-20b-5p and CPEB3. Cell counting kit-8 assay, wound healing assay, Transwell invasion assay and flow cytometry were conducted to evaluate the proliferation, migration, invasion and apoptosis of HCC cells.

RESULTS

Bioinformatics analysis suggested that miR-20b-5p and CPEB3 were markedly highly and lowly expressed, respectively, in HCC tissue in TCGA-LIHC dataset. Over-expressing miR-20b-5p facilitated the proliferation, migration and invasion, and suppressed the apoptosis of HCC cells. Dual-luciferase reporter assay validated that there was a targeting relationship between miR-20b-5p and CPEB3. The inhibitory effect of CPEB3 over-expression on HCC cell proliferation, migration and invasion was reversed by over-expressing miR-20b-5p.

CONCLUSIONS

The present study proved that miR-20b-5p promotes HCC cell proliferation, migration and invasion by inhibiting CPEB3 expression, which may provide a theoretical basis for the prognosis and treatment of HCC patients.

m6A modification of circHPS5 and hepatocellular carcinoma progression through HMGA2 expression

N6-methyladenosine (m6A) is capable of mediating circRNA generation in carcinoma biology. Nevertheless, the posttranscriptional systems of m6A and circRNA in hepatocellular carcinoma (HCC) development are still unclear. The present study identified a circRNA with m6A modification, circHPS5, which was increased in neoplasm HCC tissues and indicated poor patient survival. Silencing of circHPS5 inhibited epithelial-mesenchymal transition (EMT) and cancer stem-like cell (CSC) phenotypes. Notably, METTL3 could direct the formation of circHPS5, and specific m6A controlled the accumulation of circHPS5. YTHDC1 facilitated the cytoplasmic output of circHPS5 under m6A modification. In addition, we demonstrated that circHPS5 can act as a miR-370 sponge to regulate the expression of HMGA2 and further accelerate HCC cell tumorigenesis. Accordingly, the m6A modification of circHPS5 was found to modulate cytoplasmic output and increase HMGA2 expression to facilitate HCC development. The new regulatory model of “circHPS5-HMGA2” provides a new perspective for circHPS5 as an important prognostic marker and therapeutic target in HCC and provides mechanistic insight for exploring the carcinogenic mechanism of circHPS5 in HCC.

Transgelins: Cytoskeletal Associated Proteins Implicated in the Metastasis of Colorectal Cancer

Transgelins, including transgelin-1 (T-1), transgelin-2 (T-2), and transgelin-3 (T-3), are a family of actin-binding proteins (ABPs) that can alter the structure and morphology of the cytoskeleton. These proteins function by regulating migration, proliferation and apoptosis in many different cancers. Several studies have shown that in various types of tumor cells, including colorectal cancer (CRC) cells, and in the tumor microenvironment, the expression and biological effects of transgelins are diverse and may transform during tumor progression. Previous researches have demonstrated that transgelin levels are positively correlated with metastasis in CRC, and down-regulating their expression can inhibit this process. In advanced disease, T-1 is a tumor activator with increasing expression, and T-2 expression increases with the progression of CRC. Finally, T-3 is only expressed in neurons and is not associated with CRC. This evidence suggests that T-1 and T-2 are potential biomarkers and therapeutic targets for CRC metastasis.

MicroRNA let-7b inhibits cell proliferation via upregulation of p21 in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the most malignant tumor types and has a high incidence and mortality. Many miRNAs play important roles in the development of HCC. Identification of these miRNAs and their targets is increasingly urgent for a better understandingof miRNA function in both physiological and pathological contexts. Many studies have shown that the expression of let-7 is often downregulated in the process of tumorigenesis, suggesting that let-7 may participate in this process as an oncogene.

Methods

Immunochemistry staining was used to observe the expression of let-7b in HCC tissues. A CCK-8 assay was employed to detect the role of let-7b in the proliferation of HCC cells. The cell cycle of HCC cells was examined by flow cytometry. BALB/c nu/nu mice were used to detect the tumorigenesis potential of HCC cells; western blot and real-time PCR were employed to observe the expression of p21 in HCC cells.

Results

In our previous studies investigating HCC tissue samples obtained from the national tissue samples bank of liver cancer in Eastern Hepatobiliary Surgery Hospital, we found one abnormal expression of miRNA (let-7b), which was significantly downregulated in HCC tissue. In the current work, we studied the relationship between let-7b and HCC to potentially provide invaluable information for developing novel therapeutic strategies for treating HCC. Based on our findings, let-7b expression was absent in HCC tumors, and its lower expression was associated with poor prognosis of HCC. In further experiments, we found that let-7b inhibited HCC cell proliferation through upregulation of p21.

Conclusion

The results of our study suggested that let-7b might inhibit the proliferation of HCC cells by upregulating p21.

MiR-370 accelerated cerebral ischemia reperfusion injury via targeting SIRT6 and regulating Nrf2/ARE signal pathway

Cerebral ischemia reperfusion (CIR) is one of the highly lethal diseases in the world. MicroRNA-370 (miR-370) exerts multiple functions in different diseases. However, further research is needed to investigate the potential role of miR-370 in CIR injury. The in vivo middle cerebral artery occlusion (MCAO) rat model and in vitro oxygen-glucose deprivation/reoxygenation (OGD/R) SH-SY5Y cell model were successfully established to mimic CIR injury. The infarct sizes of brain tissues from rats were evaluated. The relationship between miR-370 and silencing information regulatory protein 6 (SIRT6) was confirmed by luciferase activity assay. The cell viability and apoptosis were determined by CCK-8 assay and terminal-deoxynucleoitidyl transferase mediated nick end labeling staining. In this study, miR-370 was upregulated in brain tissues of MCAO rats and knockdown of miR-370 decreased cerebral infarction volume of MCAO rats and it alleviated CIR injury in vivo. The in vitro experiments indicated that knockdown of miR-370 promoted cell viability and alleviated OGD/R-induced SH-SY5Y cell apoptosis. Additionally, the TargetScan predicted that SIRT6 was a target of miR-370 and confirmed by luciferase activity assay. Moreover, miR-370 inhibited SIRT6 expression and regulated Nrf2/ARE signal pathway, whereas overexpression of SIRT6 partly reversed the effect of miR-370 on OGD/R-induced SH-SY5Y cell injury. Thus, we could conclude that miR-370 accelerated CIR injury via targeting SIRT6 and regulating Nrf2/ARE signal pathway, which might provide novel therapeutic targets for CIR injury treatment.