miR-155 increases stemness and decitabine resistance in triple-negative breast cancer cells by inhibiting TSPAN5.

Effective therapeutic targets for triple-negative breast cancer (TNBC), a special type of breast cancer (BC) with rapid metastasis and poor prognosis, are lacking, especially for patients with chemotherapy resistance. Decitabine (DCA) is a Food and Drug Administration-approved DNA methyltransferase inhibitor that has been proven effective for the treatment of tumors. However, its antitumor effect in cancer cells is limited by multidrug resistance. Cancer stem cells (CSCs), which are thought to act as seeds during tumor formation, regulate tumorigenesis, metastasis, and drug resistance through complex signaling. Our previous study found that miR-155 is upregulated in BC, but whether and how miR-155 regulates DCA resistance is unclear. In this study, we demonstrated that miR-155 was upregulated in CD24- CD44+ BC stem cells (BCSCs). In addition, the overexpression of miR-155 increased the number of CD24- CD44+ CSCs, DCA resistance and tumor clone formation in MDA-231 and BT-549 BC cells, and knockdown of miR-155 inhibited DCA resistance and stemness in BCSCs in vitro. Moreover, miR-155 induced stemness and DCA resistance by inhibiting the direct target gene tetraspanin-5 (TSPAN5). We further confirmed that overexpression of TSPAN5 abrogated the effect of miR-155 in promoting stemness and DCA resistance in BC cells. Our data show that miR-155 increases stemness and DCA resistance in BC cells by targeting TSPAN5. These data provide a therapeutic strategy and mechanistic basis for future possible clinical applications targeting the miR-155/TSPAN5 signaling axis in the treatment of TNBC.

A highly significant association between Cathepsin S gene polymorphisms rs12068264 and chronic obstructive pulmonary disease susceptibility in Han Chinese population.

Cathepsin S (CTSS) and Sirtuin-1 (SIRT1) played crucial roles in the pathogenesis of chronic obstructive pulmonary disease (COPD). However, the associations between the polymorphisms of CTSS as well as SIRT1 and COPD in Asian population remain elusive. In the present study, one single nucleotide polymorphism (SNP) in rs12068264 was discovered (in 385 individuals) to be associated with the susceptibility of COPD in a Chinese Han population. The genotyping was performed using improved multiplex ligase detection reaction (iMLDR) technique. Subjects with T allele of rs12068264 in CTSS gene had an increased risk of COPD (T compared with C: odds ratio (OR) = 1.351, 95% confidence interval (95% CI): 1.008-1.811, P=0.044) compared with C allele. Subjects with TT genotype at rs12068264 had a higher risk of COPD in a recessive model (TT compared with TC + CC: OR = 2.30, 95% CI: 1.06-4.989, P=0.035). Compared with the C variant of rs12068264, the homozygous carriers of the TT genotype had higher procalcitonin (PCT) levels. Finally, haplotype analysis demonstrated that the SNPs in the CTSS and SIRT1 gene had no statistical differences between patients with COPD and the controls. In conclusion, the genetic polymorphisms of CTSS were associated with the susceptibility of COPD in a Chinese Han population, which may be helpful in understanding genetic mechanisms underlying the pathogenesis of COPD.

MiR-5100 targets TOB2 to drive epithelial-mesenchymal transition associated with activating smad2/3 in lung epithelial cells.

Idiopathic pulmonary fibrosis (IPF) is a devastating disease and the pathogenesis of IPF remains unclear. Our previous study indicated that miR-5100 promotes the proliferation and metastasis of lung epithelial cells. In this study, we investigated the effect and mechanism of miR-5100 on bleomycin (BLM)-induced mouse lung fibrosis and transforming growth factor ß (TGF-ß1) or epidermal growth factor (EGF) induced EMT-model in A549 and Beas-2B cells. The elevated level of miR-5100 was observed in both the mouse lung fibrosis tissues and EMT cell model. Furthermore, the exogenous expression of miR-5100 promoted the EMT-related changes, enhanced TGF-ß1 or EGF-induced EMT and activated the smad2/3 in lung epithelial cells, while silencing miR-5100 had the converse effects. In addition, transwell assay showed that miR-5100 can enhance cell migration. Using target prediction software and luciferase reporter assays, we identified TOB2 as a specific target of miR-5100 and miR-5100 can decrease the accumulation of endogenous TOB2 in A549 and Beas-2B cells. Moreover, the exogenous expression of TOB2 relieves the promotion of miR-5100 on EMT process and migration ability. Taken together, our results indicate that miR-5100 promotes the EMT process by targeting TOB2 associated with activating smad2/3 in lung epithlium cells. Our findings may provide novel insights into the pathogenesis of IPF.

MiR-4673 Modulates Paclitaxel-Induced Oxidative Stress and Loss of Mitochondrial Membrane Potential by Targeting 8-Oxoguanine-DNA Glycosylase-1.

BACKGROUND: Our previous study identified a novel microRNA, miR-4673, which is upregulated in A549 cells exposed to paclitaxel (PTX). In this study, we investigated the role of miR-4673 in PTX-induced cytotoxicity. METHODS: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, apoptosis assay, 5,5',6,6'-Tetrachloro-1,1',3,3'-tetraethyl-imidacarbocyanine iodide (JC-1) staining and 2',7'-Dichlorofluorescein (DCFH) staining were used to evaluate cell viability, apoptosis, mitochondrial membrane potential (MMP) loss and reactive oxygen species (ROS) generation in A549 and H1299 cells. Bioinformatics analysis and Luciferase reporter assay were used to explore whether 8-oxoguanine-DNA glycosylase-1 (OGG1) is a target gene of miR-4673. RESULTS: Enforced expression of miR-4673 decreased cell viability and increased PTX-induced apoptosis, MMP loss and reactive oxygen species (ROS) generation in A549 and H1299 cells. Bioinformatics analysis, which was used to identify potential target of miR-4673, revealed a binding site of miR-4673 in 3'UTR of OGG1. Luciferase reporters assays showed that miR-4673 specifically binds to 'CUGUUGA' in 3'UTR of OGG1. Enforced expression of miR-4673 decreased accumulation of OGG1. In addition, silencing OGG1 enhanced inhibitory effects of PTX on apoptosis, MMP loss and ROS generation, which is similar to effects of miR-4673. Moreover, enforced expression of OGG1 compromised promoting effects of miR-4673 on PTX-induced apoptosis, MMP loss and ROS generation. CONCLUSION: miR-4673 modulates PTX-induced apoptosis, MMP loss and ROS generation by targeting OGG1.

FBXO31 promotes cell proliferation, metastasis and invasion in lung cancer.

FBXO31 is a member of F-box family which is involved in diverse biological functions and development of disease. Recent reports in breast cancer, hepatocellular carcinoma and ovarian cancer demonstrated inhibitory effect of FBXO31 on proliferation and tumorigenesis. However, the function of FBXO31 is not analyzed in lung cancer so far. In this study, we reported that expression of FBXO31 was higher in lung cancer tissues compared with non-cancerous lung tissues, and that higher expression of FBXO31 was significantly associated with tumor size, tumor infiltration, clinical stages and lymph node metastasis. In addition, exogenous expression of FBXO31 promoted cell growth, metastasis and invasion in A549 cells. Conversely, silencing FBXO31 by specific siRNA caused inhibitory effect on cell growth, metastasis and invasion. Moreover, tumorigenicity assays in nude mice showed FBXO31 promoted tumor growth in vivo. In conclusion, our data suggest FBXO31 promotes cell proliferation, metastasis and invasion in lung cancer.

Five miRNAs as novel diagnostic biomarker candidates for primary nasopharyngeal carcinoma.

MicroRNAs (miRNAs) play an essential role in the development and progression of nasopharyngeal carcinomas (NPC). Despite advances in the field of cancer molecular biology and biomarker discovery, the development of clinically validated biomarkers for primary NPC has remained elusive. In this study, we investigated the expression and clinical significance of miRNAs as novel primary NPC diagnostic biomarkers. We used an array containing 2, 500 miRNAs to identify 22 significant miRNAs, and these candidate miRNAs were validated using 67 fresh NPC and 25 normal control tissues via quantitative real-time PCR (qRT-PCR). Expression and correlation analyses were performed with various statistical approaches, in addition to logistic regression and receiver operating characteristic curve analyses to evaluate diagnostic efficacy. qRT-PCR revealed five differentially expressed miRNAs (miR-93-5p, miR-135b-5p, miR-205-5p and miR-183-5p) in NPC tissue samples relative to control samples (p<0.05), with miR-135b-5p and miR-205-5p being of significant diagnostic value (p<0.01). Moreover, comparison of NPC patient clinicopathologic data revealed a negative correlation between miR-93-5p and miR- 183-5p expression levels and lymph node status (p<0.05). These findings display an altered expression of many miRNAs in NPC tissues, thus providing information pertinent to pathophysiological and diagnostic research. Ultimately, miR-135b-5p and miR-205-5p may be implicated as novel NPC candidate biomarkers, while miR- 93-5p, miR-650 and miR-183-5p may find application as relevant clinical pathology and diagnostic candidate biomarkers.

Antihyperglycemic and antioxidant activity of water extract from Anoectochilus roxburghii in experimental diabetes.

The hypoglycemic and antioxidant effects of the water extract from Anoectochilus roxburghii in alloxan-induced diabetic mice were examined. Compared with untreated diabetic mice, the daily oral administration of the water extract from A. roxburghii at 0.5 or 2 g/kg for 14 days caused a significant decrease (p<.05) in blood glucose levels with similar effect but no evidence of dose-related effect. Simultaneously, the alteration in lipid metabolism was partially attenuated as evidenced by decreased serum total cholesterol and triglyceride levels and by increased high-density lipoprotein cholesterol concentration in diabetic mice (p<.05) but no dose-related effect was observed. In addition, the water extract from A. roxburghii caused a significant increase (p<.05) in the activities of enzymic antioxidants and the levels of vitamin E in liver and kidney of diabetic mice. Our results suggest that water extract from A. roxburghii possesses hypoglycemic and antioxidant properties after oral administration to mice showing alloxan-induced diabetes.

In vitro anti-influenza virus activities of sulfated polysaccharide fractions from Gracilaria lemaneiformis.

In this paper, in vitro anti-influenza virus activities of sulfated polysaccharide fractions from Gracilaria lemaneiformis were investigated. Cytotoxicities and antiviral activities of Gracilaria lemaneiformis polysaccharides (PGL), Gracilaria lemaneiformis polysaccharide fraction-1 (GL-1), Gracilaria lemaneiformis polysaccharide fraction-2 (GL-2) and Gracilaria lemaneiformis polysaccharide fraction-3 (GL-3) were studied by the Methyl thiazolyl tetrazolium (MTT) method, and the inhibitory effect against Human influenza virus H1-364 induced cytopathic effect (CPE) on MDCK cells were observed by the CPE method. In addition, the antiviral mechanism of PGL was explored by Plaque forming unit (PFU), MTT and CPE methods. The results showed: i) Cytotoxicities were not significantly revealed, and H1-364 induced CPE was also reduced treated with sulfated polysaccharide fractions from Gracilaria lemaneiformis; ii) Antiviral activities were associated with the mass percentage content of sulfate groups in polysaccharide fractions, which was about 13%, in polysaccharides (PGL and GL-2) both of which exhibited higher antiviral activity; iii) A potential antiviral mechanism to explain these observations is that viral adsorption and replication on host cells were inhibited by sulfated polysaccharides from Gracilaria lemaneiformis. In conclusion, Anti-influenza virus activities of sulfated polysaccharide fractions from Gracilaria lemaneiformis were revealed, and the antiviral activities were associated with content of sulfate groups in polysaccharide fractions.