BACKGROUND: MicroRNAs are differentially expressed in periodontitis tissues. They are involved in cellular responses to inflammation and can be used as markers for diagnosing periodontitis. Microarray analysis showed that the expression level of microRNA-671-5p in periodontal tissues of patients with periodontitis was increased. In this study, we investigated the mechanism of action of microRNA-671-5p in human periodontal ligament stem cells (hPDLSCs) under inflammatory conditions.
RESULTS: HPDLSCs were treated with lipopolysaccharide (LPS) to establish an inflammation model. The cell survival rate was determined using the cell counting kit-8 (CCK8). Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot analyses were used to detect the expression of microRNA-671-5p and dual-specificity phosphatase (DUSP) 8 proteins, respectively, Interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α were detected using qRT-PCR and Enzyme-linked immunosorbent assay (ELISA). A dual-luciferase reporter system was employed to determine the relationship between micoRNA-671-5p and DUSP8 expression. Activation of the p38 mitogen-activated protein kinase (MAPK) signaling pathway was confirmed using western blot analysis. Following the treatment of hPDLSCs with LPS, the expression levels of microRNA-671-5p in hPDLSCs were increased, cell viability decreased, and the expression of inflammatory factors displayed an increasing trend. MicroRNA-671-5p targets and binds to DUSP8. Silencing microRNA-671-5p or overexpressing DUSP8 can improve cell survival rate and reduce inflammatory responses. When DUSP8 was overexpressed, the expression of p-p38 was reduced.
CONCLUSIONS: microRNA-671-5p targets DUSP8/p38 MAPK pathway to regulate LPS-induced proliferation and inflammation in hPDLSCs.

The antisense transcript of SATB2 protein (SATB2-AS1) is a novel long non-coding RNA (lncRNA) which is involved in the development of colorectal cancer, breast cancer and hepatocellular carcinoma. In the present study, it was aimed to investigate the consequent situation of SATB2-AS1 in tissue and cell lines of glioma. The expression of SATB2-AS1 in glioma cases was analyzed in The Cancer Genome Atlas datasets. The glycolytic metabolism was determined in glioma cells by detection of extracellular glucose level, oxygen consumption rate and extracellular acidification rate. Cell Counting Kit-8 assay and flow cytometry were used to assess cell proliferation and apoptosis in glioma cells. The interaction between SATB2-AS1 and microRNA (miR)-671-5p was verified by bioinformatic analysis, reverse transcription-quantitative PCR, dual luciferase reporter assay and RNA immunoprecipitation assay. The expression levels of the downstream targets of SATB2-AS1 were studied by western blotting. Results demonstrated that SATB2-AS1 was a downregulated lncRNA in low grade glioma and glioblastoma. Gain-of-function assay demonstrated that SATB2-AS1 inhibited cell proliferation, and glycolytic metabolism, while induced cell apoptosis in glioma cells. SATB2-AS1 sponged and suppressed the expression of an oncogenic miRNA miR-671-5p. By regulation of miR-671-5p, SATB2-AS1 upregulated cerebellar degeneration related protein 1 (CDR1) and Visinin-like 1 (VSNL1) expression in glioma cells. miR-671-5p overexpression partially reversed the antitumor effect of SATB2-AS1 in glioma. In conclusion, the current study demonstrated that there was a downregulation of SATB2-AS1 in glioma, and SATB2-AS1 regulated miR-671-5p/CDR1 axis and miR-671-5p/VSNL1 axis in glioma.

OBJECTIVE: microRNA (miR)-based therapeutic reference has been established and expanded in the treatment of cancers. For this reason, we explored how miR-671-5p regulated tumorigenicity of ovarian cancer (OC) through regulating histone deacetylase 5 (HDAC5) and hypoxia-inducible factor-1α (HIF-1α).
METHODS: miR-671-5p, HDAC5 and HIF-1α expression levels were determined in OC clinical tissues. The OC cell line H8910 was screened and transfected with the vectors that altered miR-671-5p, HDAC5 and HIF-1α levels. Finally, the proliferation, migration, invasion and apoptosis of the transfected H8910 cells were determined and the role of miR-671-5p and HDAC5 in vivo tumor growth was further discussed.
RESULTS: Low expression miR-671-5p and high expression HDAC5 and HIF-1α levels were tested in OC tissues. Up-regulating miR-671-5p or down-regulating HDAC5 or HIF-1α suppressed proliferation, migration, invasion and augmented apoptosis of H8910 cells while silenced miR-671-5p or enhanced HDAC5 caused the opposite consequences. Overexpression of HDAC5 reduced while depletion of HDAC5 enhanced the influence of up-regulated miR-671-5p on OC cell growth. In animal models, suppressing miR-671-5p or promoting HDAC5 encouraged OC tumor growth.
CONCLUSIONS: A summary delineates that miR-671-5p reduces tumorigenicity of OC via suppressing HDAC5 and HIF-1α expression levels.

Various studies have demonstrated that microRNA (miRNA) serves an important role in the development of gastric cancer. However, the expression level, clinical significance and the biological function of miRNA in gastric cancer remain largely unknown. The present study investigated the exact roles of miR-671-5p in gastric cancer, confirmed its target and explored its mechanism. Initially, the low expression levels of miR-671-5p in gastric cancer cells were confirmed by reverse transcription-quantitative polymerase chain reaction. TargetScan and MiRanda databases were utilized to forecast the target genes of miR-671-5p, and the prediction was verified by dual-luciferase reporter assay and western blot analysis. Cell Counting Kit-8 was used for cell proliferation detection. An annexin V-fluorescein isothiocyanate kit was used for cell apoptosis determination. Western blot analysis was adopted to measure the protein expression levels in different groups. The results of the present study revealed that there were lower expression levels of miR-671-5p in gastric cancer cells than in normal gastric cells. Upregulator of cell proliferation (URGCP) is a direct target of miR-671-5p and it may be negatively regulated by miR-671-5p. miR-671-5p mimics induced reduction of MKN28 cell proliferation. miR-671-5p mimics caused upregulation of MKN28 cell apoptosis. In addition, western blotting results indicated that the ratio of B-cell lymphoma 2 (Bcl-2)/Bcl-2-associated X protein was significantly decreased in the miR-671-5p mimic group compared with the negative control group (P<0.01). These results suggested that miR-671-5p had a protective role in gastric cancer through inhibiting gastric cancer cell proliferation and promoting cell apoptosis by targeting URGCP. Therefore, miR-671-5p may be an effective therapeutic target for gastric cancer.