Comprehensive bioinformation analysis of the miRNA of PLCE1 knockdown in esophageal squamous cell carcinoma.

Phospholipase C epsilon 1 (PLCE1) has been recognized as a novel susceptibility marker for esophageal squamous cell carcinoma (ESCC). The purpose of our study is to investigate its effect on the regulation of miRNA expression so as to translating the data into a novel strategy in control of ESCC. In this study, PLCE1 siRNA and vector-only plasmid were stably transfected into Eca109 and EC9706 cells and then subjected to miRNA array analysis, and quantitative real-time PCR was applied to validate miRNA array data. Then bioinformatic analyses, such as GO and pathway software, were conducted to obtain data on these differentially expressed miRNAs-targeted genes (DEGs) and clarify their function and pathway. The results showed that 36 miRNAs were found to be differentially expressed in PLCE1 siRNA-transfected cells compared with the control cells. In particular, 28 miRNAs were upregulated while 8 miRNAs were downregulated. Gene Ontology analysis showed that the function of the DEGs included cell cycle arrest, cell-matrix adhesion, apoptosis, etc. After this, the major pathways associated with the DEGs were regulation of actin cytoskeleton, TGF-beta signaling pathway, Notch signaling pathway and so on. Taken together, these results showed that the knockdown of PLCE1 may play a vital role in the control of ESCC. Further investigation will reveal and verify the function and pathway of the DEGs for the development of novel treatment strategy for the better control of ESCC.

Hypomethylation-Linked Activation of PLCE1 Impedes Autophagy and Promotes Tumorigenesis through MDM2-Mediated Ubiquitination and Destabilization of p53.

Esophageal squamous cell carcinoma (ESCC) is one of the deadliest malignant diseases. Multiple studies with large clinic-based cohorts have revealed that variations of phospholipase C epsilon 1 (PLCE1) correlate with esophageal cancer susceptibility. However, the causative role of PLCE1 in ESCC has remained elusive. Here, we observed that hypomethylation-mediated upregulation of PLCE1 expression was implicated in esophageal carcinogenesis and poor prognosis in ESCC cohorts. PLCE1 inhibited cell autophagy and suppressed the protein expression of p53 and various p53-targeted genes in ESCC. Moreover, PLCE1 decreased the half-life of p53 and promoted p53 ubiquitination, whereas it increased the half-life of mouse double minute 2 homolog (MDM2) and inhibited its ubiquitination, leading to MDM2 stabilization. Mechanistically, the function of PLCE1 correlated with its direct binding to both p53 and MDM2, which promoted MDM2-dependent ubiquitination of p53 and subsequent degradation in vitro. Consequently, knockdown of PLCE1 combined with transfection of a recombinant adenoviral vector encoding wild-type p53 resulted in significantly increased levels of autophagy and apoptosis of esophageal cancer in vivo. Clinically, the upregulation of PLCE1 and mutant p53 protein predicted poor overall survival of patients with ESCC, and PLCE1 was positively correlated with p53 in ESCC cohorts. Collectively, this work identified an essential role for PLCE1- and MDM2-mediated ubiquitination and degradation of p53 in inhibiting ESCC autophagy and indicates that targeting the PLCE1-MDM2-p53 axis may provide a novel therapeutic approach for ESCC. SIGNIFICANCE: These findings identify hypomethylation-mediated activation of PLCE1 as a potential oncogene that blocks cellular autophagy of esophageal carcinoma by facilitating the MDM2-dependent ubiquitination of p53 and subsequent degradation. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/11/2175/F1.large.jpg.

Genome-wide screening for genomic aberrations in Kazakh patients with esophageal squamous cell cancer by comparative genomic hybridization.

Multiple chromosome aberrations are responsible for tumorigenesis of esophagus squamous cell carcinoma (ESCC). To characterize genetic alterations by comparative genomic hybridization (CGH) and their relation to ESCC, We enrolled 54 members with ESCC from Kazakh's patients. We found that the deletions of 3p (P = 0.032), 17p (P = 0.004), 22q (P = 0.000) and gains of 5p (P = 0.000), 11q (P = 0.000) were significantly correlated with the location of tumors. Losses of 1p (P = 0.005), 3p (P = 0.006), 22q (P = 0.024) and gains of 3q (P = 0.043), 8q (P = 0.038), 18q (P = 0.046) were also found more frequently in patients with larger diameter disease. The loss of 19q (P = 0.005) and gains of l3q (P = 0.045), 18p (P = 0.018) were significantly correlated with pathologic grade. The gain of 7p (P = 0.009) and deletion of 19q (P = 0.018) were seen more frequently in patients with Grade III-IV tumors. Chromosome amplifications in ESCC at 1q (P = 0.008), 7p (P = 0.008), 8q (P = 0.018) and deletions at 3p (P = 0.021), 11q (P = 0.002), 17p (P = 0.012) were related to lymph node metastasis; the gains of 1q (P = 0.026) and 6q (P = 0.017) and the loss of 11q (P = 0.001) were significant in different isoforms of HPV infection. We identified some chromosomes in which the genes were related to the tumorgenesis of ESCC, which may be a theme for future investigation.

Comprehensive bioinformatics analysis of the mRNA profile of PLCE1 knockdown in esophageal squamous cell carcinoma.

The authors previously reported that Phospholipase C epsilon 1 (PLCE1) exacerbated esophageal squamous cell carcinoma (ESCC), however, the underlying mechanism remains to be fully elucidated. The present study aimed to identify key differentially expressed genes (DEGs) and signaling pathways regulated by PLCE1 in ESCC. EC9706 and Eca109 cell lines were transfected with the specific small interfering (si) RNA of PLCE1, reverse transcription­quantitative polymerase chain reaction (RT­qPCR) and western blotting were performed to detect the expression levels of PLCE1, and subsequently, mRNA array and multiple bioinformatics analysis were conducted. RT­qPCR was used to verify gene expression array results. The findings of the present study indicated that PLCE1 mRNA and protein expression were significantly suppressed (P<0.05) in the PLCE1 siRNA­transfected cells. In addition, a total of 223 DEGs with >2­fold alterations were screened between the PLCE1 siRNA­treated cells, including 168 upregulated and 53 downregulated DEGs. In particular, inflammation or immune­associated molecules, including Toll­like receptor (TLR)­4 interleukin­6, ­8 and chemokine C­X­C motif ligand 2 were significantly increased following PLCE1 knockdown. Furthermore, Gene Ontology enrichment revealed terms associated with cell proliferation, differentiation, apoptosis, signal transduction, invasion and metastasis, which may potentially be associated with PLCE1 function. Kyoto Encyclopedia of Genes and Genomes pathway analysis demonstrated 46 pathways were disturbed by DEGs, including focal adhesion, mitogen activated protein kinase, TLR, p53 and janus kinase/signal transducer and activator of transcription signaling pathways. The RT­qPCR results for validation of the selected DEGs were consistent with that of the microarray data. Overall, the results of the multiple bioinformatic analysis contributes to a systematic understanding of the roles of PLCE1 in ESCC.