Fangwei Li

Knockdown of AMPKα2 Promotes Pulmonary Arterial Smooth Muscle Cells Proliferation via mTOR/Skp2/p27Kip1 Signaling Pathway

It has been shown that activation of adenosine monophosphate-activated protein kinase (AMPK) suppresses proliferation of a variety of tumor cells as well as nonmalignant cells. In this study, we used post-transcriptional gene silencing with small interfering RNA (siRNA) to specifically examine the effect of AMPK on pulmonary arterial smooth muscle cells (PASMCs) proliferation and to further elucidate its underlying molecular mechanisms. Our results showed that knockdown of AMPKα2 promoted primary cultured PASMCs proliferation; this was accompanied with the elevation of phosphorylation of mammalian target of rapamycin (mTOR) and S-phase kinase-associated protein 2 (Skp2) protein level and reduction of p27Kip1. Importantly, prior silencing of mTOR with siRNA abolished AMPKα2 knockdown-induced Skp2 upregulation, p27Kip1 reduction as well as PASMCs proliferation. Furthermore, pre-depletion of Skp2 by siRNA also eliminated p27Kip1 downregulation and PASMCs proliferation caused by AMPKα2 knockdown. Taken together, our study indicates that AMPKα2 isoform plays an important role in regulation of PASMCs proliferation by modulating mTOR/Skp2/p27Kip1 axis, and suggests that activation of AMPKα2 might have potential value in the prevention and treatment of pulmonary arterial hypertension.

Increased DCLK1 correlates with the malignant status and poor outcome in malignant tumors: a meta-analysis

Doublecortin-like kinase 1 (DCLK1) has been found to be involved in malignant biological behavior of cancers and poor prognosis of cancer patients. The aim of this meta-analysis was to systematically clarify the relationships between expression level of DCLK1 and clinicopathological characteristics in tumors and assess its clinical value in cancer diagnosis and prognosis. 18 eligible studies with a total of 2660 patients were identified by searching the electronic bibliographic databases. Pooled results showed that DCLK1 was highly expressed in tissues from cancer patients compared to normal tissues (OR, 10.00), and overexpression of DCLK1 was significantly correlated with advanced clinical stage (OR, 2.48), positive lymph node metastasis (OR, 2.18), poorly differentiated cancers (OR, 1.83) and poor overall survival (HR, 2.15). The overall combined sensitivity and specificity for DCLK1 in distinguishing malignant tumors were 0.58 and 0.90, respectively. The mean diagnostic odds ratio was 12.70, and the corresponding area under the summary receiver operating characteristic curve was 0.78. In summary, our study indicated that DCLK1 could be a risk factor for development of malignant tumors and may serve as a promising diagnostic and prognostic biomarker for malignant tumors.

Prediction of target genes for miR‐140‐5p in pulmonary arterial hypertension using bioinformatics methods

The expression of microRNA (miR)‐140‐5p is known to be reduced in both pulmonary arterial hypertension (PAH) patients and monocrotaline‐induced PAH models in rat. Identification of target genes for miR‐140‐5p with bioinformatics analysis may reveal new pathways and connections in PAH. This study aimed to explore downstream target genes and relevant signaling pathways regulated by miR‐140‐5p to provide theoretical evidences for further researches on role of miR‐140‐5p in PAH. Multiple downstream target genes and upstream transcription factors (TFs) of miR‐140‐5p were predicted in the analysis. Gene ontology (GO) enrichment analysis indicated that downstream target genes of miR‐140‐5p were enriched in many biological processes, such as biological regulation, signal transduction, response to chemical stimulus, stem cell proliferation, cell surface receptor signaling pathways. Kyoto Encyclopedia of Genes and Genome (KEGG) pathway analysis found that downstream target genes were mainly located in Notch, TGF‐beta, PI3K/Akt, and Hippo signaling pathway. According to TF–miRNA–mRNA network, the important downstream target genes of miR‐140‐5p were PPI, TGF‐betaR1, smad4, JAG1, ADAM10, FGF9, PDGFRA, VEGFA, LAMC1, TLR4, and CREB. After thoroughly reviewing published literature, we found that 23 target genes and seven signaling pathways were truly inhibited by miR‐140‐5p in various tissues or cells; most of these verified targets were in accordance with our present prediction. Other predicted targets still need further verification in vivo and in vitro.

Activation of PPARγ inhibits HDAC1-mediated pulmonary arterial smooth muscle cell proliferation and its potential mechanisms

ABSTRACT The downstream targets of histone deacetylase 1 (HDAC1) mediation of platelet‐derived growth factor (PDGF)‐induced pulmonary arterial smooth muscle cell (PASMC) proliferation are still unclear, and it is also unknown whether activation of peroxisome proliferator‐activated receptor &ggr; (PPAR&ggr;) modulates HDAC1 and its down‐stream targets in PASMCs. The present study aims to address these issues. Our results showed that PDGF dose‐ and time‐dependently induced PASMC proliferation, and this was accompanied by an increase of HDAC1 and cyclin‐dependent kinase 4 (CDK4) protein expression as well as a reduction of microRNA‐124 (miR‐124). Pre‐silencing of HDAC1 with small interfering RNA (siRNA) abolished PDGF‐induced miR‐124 down‐regulation, CDK4 protein up‐regulation, and PASMC proliferation. In addition, over‐expression of miR‐124 reversed CDK4 protein elevation and PASMC proliferation caused by PDGF. We further found that pre‐incubation of PASMCs with pioglitazone, an agonist of PPAR&ggr; receptors, significantly increased PPAR&ggr; expression and activity, and blocked PDGF‐stimulated cell proliferation by regulating HDAC1‐mediated miR‐124 and CDK4 expression. Our study indicates that HDAC1/miR‐124/CDK4 axis plays an important role in PDGF‐induced PASMC proliferation, and activation of PPAR&ggr; inhibits PASMC proliferation by acting on HDAC1 pathway.

Overexpression of DJ-1 correlates with aggressive clinicopathological characteristics and poor prognosis in malignant tumors: a meta-analysis

Purpose A number of studies have investigated the role of DJ-1 in the development and progression of malignant tumors. This meta-analysis aims to systematically estimate the rela-tionship between the expression level of DJ-1 and the malignant biological behaviors of tumors and to assess the clinical significances of DJ-1 in the prognosis and diagnosis of cancer. Materials and methods We searched PubMed, Web of Science, China National Knowledge Infrastructure and Wanfang databases from inception to December 1, 2017. Pooled odds ratio (OR) and hazard ratio (HR) with their 95% confidence interval and the diagnostic value of DJ-1 were calculated. Results Fourteen eligible studies with a total of 1,947 subjects were enrolled in our meta-analysis. The results showed that DJ-1 was overexpressed in cancer patients compared with noncancer patients (OR = 30.72), and elevated expression of DJ-1 was demonstrated to be closely associated with high tumor-node-metastasis stage (OR = 5.52), poor differentiated degree (OR = 2.46), positive lymph node metastasis (OR = 4.12) and worse overall survival (HR = 2.23). In addition, the combined sensitivity and specificity for DJ-1 to discern malignant tumors were 0.73 and 0.93, respectively. The diagnostic OR was 34.87, and the area under the summary receiver operating characteristic curve was 0.88. Conclusion This meta-analysis demonstrated that DJ-1 was an important biomarker in tumor assessment and prognosis prediction.

The value of long noncoding RNA CASC2 as a biomarker of prognosis in carcinomas: a meta-analysis

Lnc RNA Cancer Susceptibility Candidate 2(CASC2) has been shown to be aberrantly expressed in multiple types of cancer and might serve as a prognosis biomarker. The present meta-analysis was conducted to investigate whether the expression of CASC2 was associated with prognosis or clinicopathological features in correlative cancers. A total of 11 studies with 765 cancer patients were included by searching the electronic databases, the results found a significant association between high expression of CASC2 and longer OS in cancer patients (HR=0.43, 95% CI: 0.33-0.55, P =0.000).In addition, a significant correlation was observed between high level of CASC2 and earlier TNM stage(OR = 0.30, 95% CI =0.21-0.43, P < 0.001), smaller tumor size(OR = 0.28, 95% CI =0.12-0.66, P =0.004), better tumor differentiation(OR = 0.42, 95% CI =0.27-0.66, P =0.0002). In conclusion, CASC2 can serve as a novel marker predicting the prognosis and clinicopathological features in various cancers.

COP9 signalosome subunit 6 mediates PDGF -induced pulmonary arterial smooth muscle cells proliferation

Abstract Up‐regulation of mammalian COP9 signalosome subunit 6 (CSN6) and consequent reduction of SCF ubiquitin ligase substrate receptor &bgr;‐transduction repeat‐containing protein (&bgr;‐TrCP) have been shown to be associated with cancer cells proliferation. However, it is unclear whether CSN6 and &bgr;‐TrCP are also involved in PDGF‐induced pulmonary arterial smooth muscle cells (PASMCs) proliferation. This study aims to address this issue and further explore its potential mechanisms. Our results indicated that PDGF phosphorylated Akt, stimulated PASMCs proliferation; while inhibition of PDGF receptor (PDGFR) by imatinib prevented these effects. PDGF further up‐regulated CSN6 protein expression, this was accompanied with &bgr;‐TrCP reduction and increase of Cdc25A. Inhibition of PDGFR/PI3K/Akt signaling pathway reversed PDGF‐induced such changes and cell proliferation. Prior transfection of CSN6 siRNA blocked PDGF‐induced &bgr;‐TrCP down‐regulation, Cdc25A up‐regulation and cell proliferation. Furthermore, pre‐treatment of cells with MG‐132 also abolished PDGF‐induced &bgr;‐TrCP reduction, Cdc25A elevation and cell proliferation. In addition, pre‐depletion of Cdc25A by siRNA transfection suppressed PDGF‐induced PASMCs proliferation. Taken together, our study indicates that up‐regulation of CSN6 by PDGFR/PI3K/Akt signaling pathway decreases &bgr;‐TrCP by increasing its ubiquitinated degradation, and thereby increases the expression of Cdc25A, which promotes PDGF‐induced PASMCs proliferation. HighlightsCSN6 is up‐regulated in PASMCs stimulated with PDGF.Activated PDGFR/PI3K/Akt signaling pathway up‐regulats CSN6 in PDGF‐induced PASMCs.CSN6 increases &bgr;‐TrCP ubiquitinated degradation and thereby up‐regulates Cdc25A.Up‐regulation of Cdc25A promotes PDGF‐induced PASMCs proliferation.

Interleukin-12B gene polymorphisms and bronchial asthma risk: A meta-analysis

ABSTRACT Objective: This meta-analysis aims to investigate whether interleukin-12B (IL-12B) −1188A/C or the promoter polymorphisms may be a risk factor for asthma. Data Sources: Web of Science, PubMed, China National Knowledge Infrastructure (CNKI) and Wanfang databases were searched (updated August 20, 2015). Study selections: Articles evaluating the association between IL-12B genetic polymorphisms and asthma risk were selected. Results: 13 eligible studies with a total of 5092 subjects were finally included in this meta-analysis. For IL-12B −1188A/C, analysis by ethnicity indicated that there was a markedly reduced risk for asthma in East Asian (CC + AC vs. AA: OR = 0.64, 95% CI = 0.50–0.81, P < 0.001). For IL-12B promoter, analysis by ethnicity indicated there was a markedly increased risk in East Asian (MM vs. WM + WW: OR = 1.57, 95% CI = 1.18–2.10, P = 0.002). Analysis by allergic state revealed the similar results in atopic subgroup. Conclusions: IL-12B −1188 C allele may be a protective factor against asthma in East Asian. In addition, promoter MM genotype may be a risk factor for asthma in East Asian and allergic people.