Decreased circulating miR-375: A potential biomarker for patients with non-small-cell lung cancer

MicroRNAs (miRNAs) are directly involved in cancer initiation, progression and metastasis. Alterations of miRNAs expression in cancer tissue may be reflected in circulation. We attempted to investigate the expression and clinical significance of plasma miR-20a, miR-31 and miR-375 in patients with non-small cell lung cancer (NSCLC). The plasma levels of miR-20a, miR-31 and miR-375 in 164 NSCLC patients and 164 healthy controls (discovery cohort) were evaluated and compared among various clinicopathological characteristics. The relationship between miRNA expression and clinical outcome of NSCLC patients was examined in an independent cohort (53 cases and 53 controls). The expression level of miR-375 in tissue was also examined. Plasma miR-375 levels in NSCLC patients were significantly decreased in both patient cohorts (P < 0.05). In addition, patients with metastatic NSCLC had lower plasma miR-375 expression than those with non-metastatic NSCLC (P < 0.05). Survival analysis showed that patients with low miR-375 expression had worse overall survival rates than those with high miR-375 expression (hazard ratios (HR) = 1.537 (1.046–2.258), P = 0.029). This association was independently validated in a separate cohort of 53 NSCLC patients (HR = 2.406, 95% CI 1.170–4.945, P = 0.017). The expression level of miR-375 was also found to be significantly down-regulated in NSCLC tissues compared with paracancerous tissues (P < 0.001). These findings indicate that miR-375 has an important role in NSCLC initiation and progression, and may be an independent poor prognostic factor in NSCLC patients.     

gga-miR-375 Plays a Key Role in Tumorigenesis Post Subgroup J Avian Leukosis Virus Infection

Avian leukosis is a neoplastic disease caused in part by subgroup J avian leukosis virus J (ALV-J). Micro ribonucleic acids (miRNAs) play pivotal oncogenic and tumour-suppressor roles in tumour development and progression. However, little is known about the potential role of miRNAs in avian leukosis tumours. We have found a novel tumour-suppressor miRNA, gga-miR-375, associated with avian leukosis tumorigenesis by miRNA microarray in a previous report. We have also previously studied the biological function of gga-miR-375; Overexpression of gga-miR-375 significantly inhibited DF-1 cell proliferation, and significantly reduced the expression of yes-associated protein 1 (YAP1) by repressing the activity of a luciferase reporter carrying the 3′-untranslated region of YAP1. This indicates that gga-miR-375 is frequently downregulated in avian leukosis by inhibiting cell proliferation through YAP1 oncogene targeting. Overexpression of gga-miR-375 markedly promoted serum starvation induced apoptosis, and there may be the reason why the tumour cycle is so long in the infected chickens. In vivo assays, gga-miR-375 was significantly downregulated in chicken livers 20 days after infection with ALV-J, and YAP1 was significantly upregulated 20 days after ALV-J infection (P<0.05). We also found that expression of cyclin E, an important regulator of cell cycle progression, was significantly upregulated (P<0.05). Drosophila inhibitor of apoptosis protein 1 (DIAP1), which is related to caspase-dependent apoptosis, was also significantly upregulated after infection. Our data suggests that gga-miR-375 may function as a tumour suppressor thereby regulating cancer cell proliferation and it plays a key role in avian leukosis tumorigenesis.     

Downregulation of microRNA-214 and overexpression of FGFR-1 contribute to hepatocellular carcinoma metastasis

miR-214 is one of the most significantly downregulated microRNAs (miRNAs) in hepatocellular carcinoma (HCC). Fibroblast growth factor receptor 1 (FGFR-1) is a miR-214 target gene implicated in the progression of HCC. However, the roles of miR-214 and FGFR-1 in HCC are not fully understood. Here, we analyzed the expression of miR-214 and FGFR-1 in 65 cases of HCC and paired non-neoplastic tissue specimens using real-time PCR and Western blot (WB), respectively. Our data indicated that miR-214 was downregulated and FGFR-1 was overexpressed in HCC compared to the paired non-neoplastic tissues. The low miR-214 expression was correlated with portal vein invasion (p = 0.016) and early recurrence (p = 0.045) in HCC patients. Moreover, the low miR-214 expression was correlated with high positive rate of FGFR-1 in HCC cases (p = 0.020). Our data further demonstrated that miR-214 overexpression in SK-HEP1 and HepG2 cells downregulated FGFR-1 expression and inhibited liver cancer cell invasion. The Luciferase assay results further demonstrated the targeted regulation of FGFR-1 by miR-214. In conclusion, our data indicate that the downregulation of miR-214 in HCC and the upregulation of its target gene FGFR-1 is associated with HCC progression. Therefore, miR-214 and FGFR-1 are potential prognostic markers and therapeutic targets in HCC.     

MiR-375-3p alleviates the severity of inflammation through targeting YAP1/LEKTI pathway in HaCaT cells

ABSTRACT

Atopic dermatitis (AD) is a relapsing inflammatory skin disease with a complicated pathogenesis. This study aimed to investigate whether miR-375-3p could regulate AD through the Yes-associated protein 1 (YAP1) pathway. In this study, inflammatory response was induced by TNF-α and IFN-γ administration in HaCaT cells. We found that viability and inflammatory factor release, including interleukin-1β (IL-1β) and IL-6, were negatively related to miR-375-3p expression in HaCaT cells. We also found that YAP1 overexpression down-regulated lympho-epithelial Kazal type inhibitor (LEKTI) levels and aggravated viability and inflammation in TNF-α and IFN-γ-treated HaCaT cells. Dual-luciferase reporter assay proved the targeted binding of miR-375-3p and YAP1 3?-UTR. Additionally, the protective effect of miR-375-3p on inflammatory response in TNF-α and IFN-γ-treated HaCaT cells could be impeded by YAP1 overexpression. Collectively, our results suggested that miR-375-3p could modulate HaCaT cell viability and inflammation through the YAP1/LEKTI pathway.     

An insertion/deletion polymorphism in the 3′ untranslated region of β-transducin repeat-containing protein (βTrCP) is associated with susceptibility for hepatocellular carcinoma in Chinese

Hepatocellular carcinoma (HCC) is an epithelial cancer which originates from hepatocytes or their progenitors. As a positive regulator of NFκB signaling pathway, β-transducin repeat-containing protein (βTrCP) is overexpressed and oncogenic in epithelial cancers, suggesting a potential role of βTrCP in HCC susceptibility. We carried out a case-control study in a Chinese population (256 cases and 367 controls) to estimate the susceptibility to HCC associated with a 9 bp insertion/deletion polymorphism (rs16405) in 3′ untranslated region of βTrCP. Using unconditional logistic regression, we found that 9N del/del and 9N ins/del genotypes were significantly associated with decreased HCC risk: OR = 0.44 (0.24-0.83) (p = 0.004) and OR = 0.56 (0.31-1.00) (p = 0.034), respectively. Furthermore, in vivo experiments showed that mRNA levels of βTrCP from HCC tumor tissues were correlated with rs16405 genotypes. HCC tumor tissues with homozygous for 9N ins/ins has the highest level of βTrCP, which are 3.99 and 7.04-fold higher than heterozygous 9N ins/del and homozygous 9N del/del, respectively. Based on bioinformatics prediction, we found that the risk allele for rs16405 disrupted a binding site for human microRNA-920 which would negatively regulate βTrCP. We propose a microRNA-920 mediated βTrCP regulation model depending on rs16405 genotype, which warrants further replication association studies and follow-up functional experiments.     

Promoter polymorphisms of pri-miR-34b/c are associated with hepatocellular carcinoma

Background

Numerous studies have focused on the association between miR-34 family members, which are direct p53 targets, and carcinogenesis of many cancers, including hepatocellular carcinoma (HCC). This study aimed to assess whether polymorphisms in the single-nucleotide polymorphism miR-34b/c T>C (rs4938723) and TP53 Arg72Pro (rs1042522) increase the risk of HCC and influence outcome in patients with HCC.

Patients and methods

We enrolled 157 HCC patients and 201 cancer-free control subjects from the Korean population. MicroRNA polymorphisms were genotyped using the polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) method.

Results

We found that the miR-34b/c TC + CC frequency was significantly higher in HCC patients than in controls (adjusted odds ratio [AOR]: 1.580; 95% confidence interval [CI]: 1.029–2.426). The miR-34b/c CC-TP53 Arg/Arg combination significantly increased the risk of HCC (AOR: 13.644; 95% CI: 1.451–128.301). The SNPs miR-34b/c T>C and TP53 Arg72Pro(G>C) had no influence on survival of HCC patients.

Conclusions

Our findings suggest that loss of the T allele in miR-34b/c T>C, and the miR-34b/c CC-TP53 Arg/Arg combination increases the risk of HCC in the Korean population.     

Dehydration mediated microRNA response in the African clawed frog Xenopus laevis

Exposure to various environmental stresses induces metabolic rate depression in many animal species, an adaptation that conserves energy until the environment is again conducive to normal life. The African clawed frog, Xenopus laevis, is periodically subjected to arid summers in South Africa, and utilizes entry into the hypometabolic state of estivation as a mechanism of long term survival. During estivation, frogs must typically deal with substantial dehydration as their ponds dry out and X. laevis can endure > 30% loss of its body water. We hypothesize that microRNAs play a vital role in establishing a reversible hypometabolic state and responding to dehydration stress that is associated with amphibian estivation. The present study analyzes the effects of whole body dehydration on microRNA expression in three tissues of X. laevis. Compared to controls, levels of miR-1, miR-125b, and miR-16-1 decreased to 37 ± 6, 64 ± 8, and 80 ± 4% of control levels during dehydration in liver. By contrast, miR-210, miR-34a and miR-21 were significantly elevated by 3.05 ± 0.45, 2.11 ± 0.08, and 1.36 ± 0.05-fold, respectively, in the liver. In kidney tissue, miR-29b, miR-21, and miR-203 were elevated by 1.40 ± 0.09, 1.31 ± 0.05, and 2.17 ± 0.31-fold, respectively, in response to dehydration whereas miR-203 and miR-34a were elevated in ventral skin by 1.35 ± 0.05 and 1.74 ± 0.12-fold, respectively. Bioinformatic analysis of the differentially expressed microRNAs suggests that these are mainly involved in two processes: (1) expression of solute carrier proteins, and (2) regulation of mitogen-activated protein kinase signaling. This study is the first report that shows a tissue specific mode of microRNA expression during amphibian dehydration, providing evidence for microRNAs as crucial regulators of metabolic depression.     

miR-122 Targets Pyruvate Kinase M2 and Affects Metabolism of Hepatocellular Carcinoma

In contrast to normal differentiated cells that depend on mitochondrial oxidative phosphorylation for energy production, cancer cells have evolved to utilize aerobic glycolysis (Warburg’s effect), with benefit of providing intermediates for biomass production. MicroRNA-122 (miR-122) is highly expressed in normal liver tissue regulating a wide variety of biological processes including cellular metabolism, but is reduced in hepatocellular carcinoma (HCC). Overexpression of miR-122 was shown to inhibit cancer cell proliferation, metastasis, and increase chemosensitivity, but its functions in cancer metabolism remains unknown. The present study aims to identify the miR-122 targeted genes and to investigate the associated regulatory mechanisms in HCC metabolism. We found the ectopic overexpression of miR-122 affected metabolic activities of HCC cells, evidenced by the reduced lactate production and increased oxygen consumption. Integrated gene expression analysis in a cohort of 94 HCC tissues revealed miR-122 level tightly associated with a battery of glycolytic genes, in which pyruvate kinase (PK) gene showed the strongest anti-correlation coefficient (Pearson r = −0.6938, p = <0.0001). In addition, reduced PK level was significantly associated with poor clinical outcomes of HCC patients. We found isoform M2 (PKM2) is the dominant form highly expressed in HCC and is a direct target of miR-122, as overexpression of miR-122 reduced both the mRNA and protein levels of PKM2, whereas PKM2 re-expression abrogated the miR-122-mediated glycolytic activities. The present study demonstrated the regulatory role of miR-122 on PKM2 in HCC, having an implication of therapeutic intervention targeting cancer metabolic pathways.     

Quantitative analysis of RASSF1A promoter methylation in hepatocellular carcinoma and its prognostic implications

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide and is caused by the accumulation of genetic and epigenetic alterations in regulatory genes. In this study, we used methylight to detect the methylation status of the RASSF1A promoter in 87 paired HCC samples and analysed the relationship between methylation status and clinicopathological parameters, including prognosis after surgery. We found that the methylation level of the RASSF1A promoter in HCC tissues was significantly higher than that in the corresponding non-tumorous tissues (p < 0.0001). Furthermore, the methylation level of the RASSF1A gene promoter in HCC samples was higher in patients with a tumor size ?6 cm (p = 0.0149) and in patients younger than 50 years old (p = 0.0175). However, hypermethylation of the RASSF1A promoter in HCC tissues did not affect the overall survival of patients (p = 0.611). Thus, RASSF1A promoter hypermethylation may not be a useful biomarker for the prognosis of HCC.     

MicroRNA-224 upregulation and AKT activation synergistically predict poor prognosis in patients with hepatocellular carcinoma

Background and aimPrevious evidence has shown that microRNA (miR)-224 may function as an onco-miRNA in hepatocellular carcinoma (HCC) cells by activating AKT signaling. However, little is known about the clinical significance of the combined expression of miR-224 and phosphorylated-AKT (pAKT) on human HCC. The aim of this study was to investigate the synergistical influence of miR-224 and pAKT on clinical characteristics and prognosis in patients with HCC.MethodsOne-hundred and thirty HCC patients who had undergone curative liver resection were selected. In situ hybridization and immunohistochemistry were respectively performed to detect the expression of miR-224 and pAKT in the respective tumors.ResultsCompared with the adjacent nonneoplastic liver tissues, the expression levels of miR-224 and pAKT protein in HCC tissues were both significantly increased (both P < 0.001). In addition, the combined upregulation of miR-224 and pAKT protein was significantly associated with serum AFP (P = 0.01), tumor stage (P = 0.002) and tumor grade (P = 0.008). Moreover, HCC patients highly expressing both miR-224 and pAKT protein had worse 5-year disease-free survival and 5-year overall survival (both P < 0.001). Furthermore, the Cox proportional hazards model showed that the combined upregulation of miR-224 and pAKT protein (miR-224-high/pAKT-high) may be independent poor prognostic factors for both 5-year disease-free survival (P = 0.008) and 5-year overall survival (P = 0.01) in HCC.ConclusionThese results indicate for the first time that miR-224 upregulation and AKT activation may synergistically associate with tumor progression of HCC. The combined high expression of miR-224 and pAKT may be a potential indicator for predicting unfavorable prognosis in HCC patients.     

Oncogenic virus-associated neoplasia: a role for cyclin D1 genotypes influencing the age of onset of disease?

Cyclin D1 (CCND1) is a key regulatory protein at the G1/S checkpoint of the cell cycle. The purpose of our study was to assess the role of CCND1 genotypes influencing the age of onset of oncogenic virus-associated neoplasia. We conducted a hospital-based case-control study of 581 individuals, including 247 controls and 334 cases (108 nasopharyngeal and 226 cervical cancer cases). The polymorphism analysis was performed in blood samples by PCR-RFLP methodology. Age-adjusted logistic regression analysis indicates that individuals carrying two G-alleles have an increased genetic susceptibility for the development of oncogenic virus-associated cancers (aOR = 2.02, 95% CI 1.30-3.14, P = 0.002). Moreover, our results indicate that the waiting time for onset of oncogenic virus-associated neoplasia in patients homozygous (GG) for CCND1 genotypes (52 years) was 12 years earlier in comparison with patients carrying AG or AA genotypes (60 years) (log-rank test: P = 0.0003). Our results may be important in contributing to a more extensive knowledge of the mechanisms involved in oncogenic virus-associated carcinogenesis, as CCND1 may be an important target for the development of new strategies for cancer treatment and prevention.     

Three common functional polymorphisms in microRNA encoding genes in the susceptibility to hepatocellular carcinoma: A systematic review and meta-analysis

Emerging evidences have shown that common genetic polymorphisms in microRNAs may be associated with the development of hepatocellular carcinoma (HCC); but individually published studies and previous meta-analyses revealed inconclusive results. The aims of this review and meta-analysis are to assess whether common single-nucleotide polymorphisms (SNPs) in the genes encoding the microRNAs are associated with susceptibility to HCC development and clinicopathologic characteristics of hepatitis B virus (HBV) related HCC. A computerized search was performed in PubMed, Embase, Web of Science and China BioMedicine (CBM) databases to identify relevant articles published before January 1st 2013. Ten case–control studies were assessed with a total of 3437 cases and 3437 healthy controls. Three common functional SNPs in miRNA-encoding genes were found, including miR-146a G > C (rs2910164), miR-196a-2 C > T (rs11614913) and miR-499 T > C (rs3746444). This meta-analysis revealed that the miR-146a*C variant was associated with a decrease in HCC risk, especially among Asian and male populations; while the miR-196a-2*T variant was associated with susceptibility to HCC among Caucasian populations. However, we failed to find any significant correlations between the miR-499*C polymorphism and HCC risks. When further stratification on HBV status was conducted, a similar trend of association between the three SNPs and the HBV-related HCC risks was observed, but these results were not statistically significant due to small sample sizes. The current meta-analysis demonstrates that SNPs contained in the genes encoding miR-146a and miR-196a-2 may play a major role in genetic susceptibility to HCC.