microRNAs: Novel regulators of the TGF-β pathway in pancreatic ductal adenocarcinoma

A concise review on the role of MIR100HG in human disorders

MIR100HG is a long non-coding RNA (lncRNA) encoded by a locus on chr11:122,028,203-122,556,721. This gene can regulate cell proliferation, apoptosis, cell cycle transition and cell differentiation. MIR100HG was firstly identified through a transcriptome analysis and found to regulate differentiation of human neural stem cells. It is functionally related with a number of signalling pathways such as TGF-β, Wnt, Hippo and ERK/MAPK signalling pathways. Dysregulation of MIR100HG has been detected in a diversity of cancers in association with clinical outcomes. Moreover, it has a role in the pathophysiology of dilated cardiomyopathy, intervertebral disk degeneration and pulmonary fibrosis. The current study summarizes the role of these lncRNAs in human disorders.

LncmiRHG-MIR100HG: A new budding star in cancer

MIR100HG, also known as lncRNA mir-100-let-7a-2-mir-125b-1 cluster host gene, is a new and critical regulator in cancers in recent years. MIR100HG is dysregulated in various cancers and plays an oncogenic or tumor-suppressive role, which participates in many tumor cell biology processes and cancer-related pathways. The errant expression of MIR100HG has inspired people to investigate the function of MIR100HG and its diagnostic and therapeutic potential in cancers. Many studies have indicated that dysregulated expression of MIR100HG is markedly correlated with poor prognosis and clinicopathological features. In this review, we will highlight the characteristics and introduce the role of MIR100HG in different cancers, and summarize the molecular mechanism, pathways, chemoresistance, and current research progress of MIR100HG in cancers. Furthermore, some open questions in this rapidly advancing field are proposed. These updates clarify our understanding of MIR100HG in cancers, which may pave the way for the application of MIR100HG-targeting approaches in future cancer diagnosis, prognosis, and therapy.

Key LncRNAs Associated With Oxidative Stress Were Identified by GEO Database Data and Whole Blood Analysis of Intervertebral Disc Degeneration Patients

Background: Intervertebral disc degeneration (IDD) is a major cause of low back pain, but the onset and progression of IDD are unknown. Long non-coding RNA (lncRNA) has been validated to play a critical role in IDD, while an increasing number of studies have linked oxidative stress (OS) to the initiation and progression of IDD. We aim to investigate key lncRNAs in IDD through a comprehensive network of competing endogenous RNA (ceRNA) and to identify possible underlying mechanisms.

Methods: We downloaded IDD-related gene expression data from the Gene Expression Omnibus (GEO) database and obtained differentially expressed-lncRNAs (DE-lncRNA), -microRNAs (DE-miRNA), and -messenger RNAs (DE-mRNA) by bioinformatics analysis. The OS-related lncRNA-miRNA-mRNA ceRNA interaction axis was constructed and key lncRNAs were identified based on ceRNA theory. We performed gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses on mRNAs regulated by lncRNAs in the ceRNA network. Single sample gene set enrichment analysis (ssGSEA) was used to reveal the immune landscape. Expression of key lncRNAs in IDD was assessed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR).

Results: In this study, 111 DE-mRNAs, 20 DE-lncRNAs, and 502 DE-miRNAs were identified between IDD patients and controls, and 16 OS-related DE-lncRNAs were also identified. The resulting lncRNA-miRNA-mRNA network consisted of eight OS-related DE-lncRNA nodes, 24 DE-miRNA nodes, 70 DE-mRNA nodes, and 183 edges. Functional enrichment analysis suggested that the ceRNA network may be involved in regulating biological processes related to cytokine secretion, lipid, and angiogenesis. We also identified four key lncRNAs, namely lncRNA GNAS-AS1, lncRNA MIR100HG, lncRNA LINC01359, and lncRNA LUCAT1, which were also found to be significantly associated with immune cells.

Conclusion: These results provide novel insights into the potential applications of OS-related lncRNAs in patients with IDD.

MicroRNA-1252-5p, regulated by Myb, inhibits invasion and epithelial-mesenchymal transition of pancreatic cancer cells by targeting NEDD9

MicroRNAs (miRNAs) are known to be involved in the development and progression of pancreatic cancer (PAC). The expression levels and roles of miR-1252-5p in PAC remain unclear. Quantitative real-time PCR and in situ hybridization were used to detect miR-1252-5p expression in PAC cells and human tissues. We studied the gain and loss of function of miR-1252-5p in the PAC cell lines in vitro and in vivo. The direct targets of miR-1252-5p were analyzed using public databases and a dual-luciferase reporter assay. Expression levels of miR-1252-5p are downregulated in PAC cell lines and tissue samples, and its expression is negatively associated with adverse clinical features and poor prognosis. In vitro and in vivo experiments show that miR-1252-5p overexpression inhibits the proliferation, migration, invasion, and epithelial-mesenchymal transition of PAC cells, and miR-1252-5p knockdown enhances these biological behaviors. MiR-1252-5p negatively regulates neural precursor cell expressed, developmentally downregulated 9 (NEDD9) by directly binding its 3'- untranslated region. Further mechanism research revealed that the SRC/STAT3 pathway is involved in miR-1252-5p/NEDD9 mediation of PAC's biological behaviors. We also verified that Myb inhibited miR-1252-5p by directly binding at its promoter. MiR-1252-5p may act as a tumor-suppressing miRNA in PAC and may be a potential therapeutic target for PAC patients.

Epigenetic regulation of cancer stem cell formation and maintenance

Cancerous tumours contain a rare subset of cells with stem-like properties that are termed cancer stem cells (CSCs). CSCs are defined by their ability to divide both symmetrically and asymmetrically, to initiate new tumour growth and to tolerate the foreign niches required for metastatic dissemination. Accumulating evidence suggests that tumours arise from cells with stem-like properties, the generation of CSCs is therefore likely to be an initiatory event in carcinogenesis. Furthermore, CSCs in established tumours exist in a dynamic and plastic state, with nonstem tumour cells thought to be capable of de-differentiation to CSCs. The regulation of the CSC state both during tumour initiation and within established tumours is a desirable therapeutic target and is mediated by epigenetic factors. In this review, we will explore the epigenetic parallels between induced pluripotency and the generation of CSCs, and discuss how the epigenetic regulation of CSCs opens up novel opportunities for therapeutic intervention.

Anti-Proliferative and Apoptosis-Promoting Effect of microRNA-125b on Pancreatic Cancer by Targeting NEDD9 via PI3K/AKT Signaling

PURPOSE

The expression of microRNA-125b (miR-125b) is low in a variety of cancers, including gastric, lung, bladder, thyroid, and esophageal cancers. However, its specific mechanism in pancreatic ductal adenocarcinoma (PDAC) remains unclear. This study is aimed to explore the role of miR-125b in PDAC.

METHODS

PDAC tissues and adjacent tissues were collected for miR-125b analysis by qRT-PCR. Different PDAC cell lines were cultured for miR-125b detection by qRT-PCR, and CAPAN1 cells were selected for the downstream experiments. Cell proliferation was characterized by methyl thiazolyl tetrazolium (MTT) and 5-bromo-2-deoxyUridine (BrdU) staining. Flow cytometry was utilized for apoptosis and cell cycle changes. Cell invasion was determined by the Transwell assay and the dual-luciferase assay was utilized for validating the target gene. Western blotting was used to detect apoptosis related and PI3K/AKT signaling proteins.

RESULTS

miR-125b was significantly down-regulated in human PDAC tissues and cell lines (P < 0.05). miR-125b inhibited the growth and invasion of CAPAN1 cells, facilitated apoptosis, and blocked the cell cycle at the G0/G1 phase. Furthermore, miR-125 directly targeted NEDD9. The high expression of NEDD9 impaired the anti-proliferative and anti-apoptotic activity of miR-125b. miR-125b also inhibited apoptosis-related proteins and PI3K/AKT signaling pathways via NEDD9.

CONCLUSION

miR-125b decreased cell growth and invasion, and facilitated apoptosis in CAPAN1 cells through PI3K/AKT inhibition via targeting NEDD9.