The etiology of cancer includes aberrant cellular homeostasis where a compromised RNA regulatory network is a prominent contributing factor. In particular, noncoding RNAs including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) were recently shown to play important roles in the initiation, progression, and metastasis of human cancers. Nonetheless, a mechanistic understanding of noncoding RNA functions in lung squamous cell carcinoma (LUSC) is lacking. To fill this critical gap in knowledge, we obtained mRNA, miRNA, and lncRNA expression data on patients with LUSC from the updated Cancer Genome Atlas (TCGA) database (2016). We successfully identified 3,366 mRNAs, 79 miRNAs, and 151 lncRNAs as key contributing factors of a high risk of LUSC. Furthermore, we hypothesized that the lncRNA–miRNA–mRNA regulatory axis positively correlates with LUSC and constructed a competitive endogenous RNA (ceRNA) network of LUSC by targeting interrelations with significantly aberrant expression data between miRNA and mRNA or lncRNA. Six ceRNAs (PLAU, miR-31-5p, miR-455-3p, FAM83A-AS1, MIR31HG, and MIR99AHG) significantly correlated with survival (P < 0.05). Finally, real-time quantitative PCR analysis showed that PLAU is significantly upregulated in SK-MES-1 cells compared with 16-BBE-T cells. Taken together, our findings represent new knowledge for a better understanding the ceRNA network in LUSC biology and pave the way to improved diagnosis and prognosis of LUSC.
Classical swine fever virus (CSFV) replicates in macrophages and causes persistent infection. Despite its role in disastrous economic losses in swine industries, the molecular mechanisms underlying its pathogenesis are poorly understood. The virus evades the neutralizing immune response, subverting the immune system to ensure its own survival and persistence. Our genome-wide analysis of porcine alveolar macrophage transcriptional responses to CSFV Shimen infection using the Solexa/Illumina digital gene expression system revealed that p53 pathway components and cell cycle molecules were differentially regulated during infection compared to controls. Further, we investigated the molecular changes in macrophages infected with CSFV Shimen, focusing on the genes involved in the p53 pathway. CSFV Shimen infection led to phosphorylation and accumulation of p53 in a time-dependent manner. Furthermore, CSFV Shimen infection upregulated cyclin-dependent kinase inhibitor 1A (p21) mRNA and protein. In addition, CSFV Shimen infection induced cell cycle arrest at the G1 phase, as well as downregulation of cyclin E1 and cyclin-dependent kinase 2 (CDK2). The expression of genes in the p53 pathway did not change significantly after p53 knockdown by pifithrin-α during CSFV Shimen infection. Our data suggest that CSFV Shimen infection increases expression of host p53 and p21, and inhibits expression of cyclin E1 and CDK2, leading to cell cycle arrest at the G1 phase. CSFV may utilize this strategy to subvert the innate immune response and proliferate in host cells.
Background
The Shimen strain of classical swine fever (CSF) virus (CSFV) causes CSF, which is mainly characterised by disseminated intravascular haemorrhage. Macrophages are an essential component of innate immunity against pathogenic microorganisms; however, the role of macrophages in CSF pathogenesis remains unclear. To illuminate the infective mechanism of CSFV, we used gene co-expression networks derived from macrophages infected with CSFV Shimen and CSFV C as well as uninfected macrophages to screen key regulatory genes, and their contributions to the pathogenesis of CSF were discussed.
Results
Vascular endothelial growth factor A (
VEGFA
) and plasminogen activator, urokinase (
PLAU
, which encodes urokinase-type plasminogen activator [uPA]) were identified as coordinated genes expressed in macrophages by gene co-expression networks. Quantitative polymerase chain reaction and western blot analysis confirmed that
VEGFA
and
PLAU
were significantly up-regulated at both the transcription and translation levels after infection. Further, confocal microscopy analysis proposed that the VEGFA and uPA proteins were temporally co-localised with the CSFV protein E2.
Conclusions
Our findings suggest that co-expression of
VEGFA
and
PLAU
in macrophages contributes to CSFV Shimen infection and serves as a significant avenue for the strain to form an inflammatory microenvironment, providing new insight into the mechanisms of CSF caused by a virulent strain.
Electronic supplementary material
The online version of this article (10.1186/s12917-019-1826-8) contains supplementary material, which is available to authorized users.
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