Bioinformatics Analysis of Core Genes and Key Pathways in Myelodysplastic Syndrome / 中国实验血液学杂志

OBJECTIVE@#To screen differentially expressed gene (DEG) related to myelodysplastic syndrome (MDS) based on Gene Expression Omnibus (GEO) database, and explore the core genes and pathogenesis of MDS by analyzing the biological functions and related signaling pathways of DEG.@*METHODS@#The expression profiles of GSE4619, GSE19429, GSE58831 including MDS patients and normal controls were downloaded from GEO database. The gene expression analysis tool (GEO2R) of GEO database was used to screen DEG according to | log FC (fold change) |≥1 and P<0.01. David online database was used to annotate gene ontology function (GO). Metascape online database was used to enrich and analyze differential genes in Kyoto Encyclopedia of Genes and Genomes (KEGG). The protein-protein interaction network (PPI) was constructed by using STRING database. CytoHubba and Mcode plug-ins of Cytoscape were used to analyze the key gene clusters and hub genes. R language was used to diagnose hub genes and draw the ROC curve. GSEA enrichment analysis was performed on GSE19429 according to the expression of LEF1.@*RESULTS@#A total of 74 co-DEG were identified, including 14 up-regulated genes and 60 down regulated genes. GO enrichment analysis indicated that BP of down regulated genes was mainly enriched in the transcription and regulation of RNA polymerase II promoter, negative regulation of cell proliferation, and immune response. CC of down regulated genes was mainly enriched in the nucleus, transcription factor complexes, and adhesion spots. MF was mainly enriched in protein binding, DNA binding, and β-catenin binding. KEGG pathway was enriched in primary immunodeficiency, Hippo signaling pathway, cAMP signaling pathway, transcriptional mis-regulation in cancer and hematopoietic cell lineage. BP of up-regulated genes was mainly enriched in type I interferon signaling pathway and viral response. CC was mainly enriched in cytoplasm. MF was mainly enriched in RNA binding. Ten hub genes and three important gene clusters were screened by STRING database and Cytoscape software. The functions of the three key gene clusters were closely related to immune regulation. ROC analysis showed that the hub genes had a good diagnostic significance for MDS. GSEA analysis indicated that LEF1 may affect the normal function of hematopoietic stem cells by regulating inflammatory reaction, which further revealed the pathogenesis of MDS.@*CONCLUSION@#Bioinformatics can effectively screen the core genes and key signaling pathways of MDS, which provides a new strategy for the diagnosis and treatment of MDS.

Recent advances in novel anticancer agents targeting β-catenin/TCF4 interaction for molecular cancer therapeutics / 药学学报

Wnt/β-catenin signaling pathway plays an important role in the proliferation, growth, invasion, and metastasis of human cancers. Moreover, β-catenin/T-cell factor 4 (TCF4) interaction regulates the transcription of the key oncogenes in Wnt/β-catenin signaling pathway. Therefore, β-catenin/TCF4 interaction would be a promising therapeutic target for the development of highly selective anticancer agents. At present, most ongoing small-molecule inhibitors targeting β-catenin/TCF4 interaction, including PKF222-815, iCRT3/5/14, LF3, and sanguinarine, have been developed in preclinical studies for human cancer therapeutics. In this review, we summarized the research advances of up-to date inhibitors targeting β-catenin/TCF4 interaction, including the molecular structure and cellular functions of β-catenin in canonical Wnt signaling pathway. This review holds a hopeful avenue for the development of novel and highly selective Wnt inhibitors targeting β-catenin/TCF4 interaction for future anticancer strategy.

Development of an ELISA-based high throughput screening method for novel anticancer agents targeting β-catenin/Lef1 interaction / 生物工程学报

To develop an enzyme-linked immunosorbent assay (ELISA)-based high throughput screening (HTS) method for β-catenin/Lef1 interaction antagonists screening, Escherichia coli Rosetta (DE3) competent cells were transformed with β-catenin-pET-30a(+) plasmid. β-catenin protein was expressed after induction and purified using affinity chromatography. The biological activity of purified β-catenin was further analyzed by GST Pulldown assay. The β-catenin/GST-Lef1 binding model was established using ELISA principle, and the ELISA-based HTS method was further optimized through determination of an optimal coated concentration of GST-Lef1 and working concentration of β-catenin. The results showed that β-catenin protein was successfully expressed and purified. The GST Pulldown assay demonstrated a perfect biological activity for purified β-catenin. Subsequently, the ELISA-based HTS method was performed using 10 μg/mL GST-Lef1 and 6 μg/mL β-catenin, with the Z factor of 0.76. Taken together, we have successfully developed a simple, robust and reliable ELISA-based HTS method for screening of novel Wnt inhibitors targeting β-catenin/Lef1 interaction.

Pja2 Inhibits Wnt/β-catenin Signaling by Reducing the Level of TCF/LEF1

Ubiquitination of proteins plays an essential role in various cellular processes, including protein degradation, DNA repair, and cell signaling pathways. Previous studies have shown that protein ubiquitination is implicated in regulating pluripotency as well as fate determination of stem cells. To identify how protein ubiquitination affects differentiation of embryonic stem cells, we analyzed microarray data, which are available in the public domain, of E3 ligases and deubiquitinases whose levels changed during stem cell differentiation. Expression of pja2, a member of the RING-type E3 ligase family, was up-regulated during differentiation of stem cells. Wnt/β-catenin signaling is one of the most important signaling pathways for regulation of the self-renewal and differentiation of embryonic stem cells. Pja2 was shown to bind to TCF/LEF1, which are transcriptional factors for Wnt/β-catenin signaling, and regulate protein levels by ubiquitination, leading to down-regulation of Wnt signaling activity. Based on these results, we suggest that E3 ligase Pja2 regulates stem cell differentiation by controlling the level of TCF/LEF1 by ubiquitination.

Expressions of β-catenin and LEF1 in acute leukemia and their correlation / 实用医学杂志

Objective To investigate the expressions of β-catenin and lymphoid enhancer factor 1(LEF1) mRNA in acute leukemia(AL)and their correlation. Methods Real-time PCR was used to examine the expres-sions of β-catenin and LEF1 mRNA in 62 de novo acute myeloid leukemia(AML)patients,23 de novo acute lymphoblastic leukemia(ALL)patients,20 controls and 4 kinds of cell lines:K562,HL-60,THP-1 and Raji. Results The expression level of β-catenin in AML group was significantly higher compared with the control group,but LEF1 mRNA expression in AML group was significantly lower than that in the control group (P <0.05). The expression levels of β-catenin and LEF1 mRNA were all significantly higher in ALL group compared with the control group (P < 0.05). There were significantly positive correlations between β-catenin and LEF1 mRNA expressions both in AML and in ALL groups(P<0.05). Among the three AML cell lines,THP-1 cell had the highest β-catenin mRNA expression and the lowest LEF1 mRNA expression,and the expression tendencies of these two genes in THP-1 cell line were in accordance with those in AML patients. Conclusions Activation of Wnt/β-catenin pathway happends in AL patients and β-catenin/LEF1 may play a role in leukemogenensis of ALL.

Identification of LEF1 as a Susceptibility Locus for Kawasaki Disease in Patients Younger than 6 Months of Age

Kawasaki disease (KD) is an acute febrile vasculitis predominately affecting infants and children. The dominant incidence age of KD is from 6 months to 5 years of age, and the incidence is unusual in those younger than 6 months and older than 5 years of age. We tried to identify genetic variants specifically associated with KD in patients younger than 6 months or older than 5 years of age. We performed an age-stratified genome-wide association study using the Illumina HumanOmni1-Quad BeadChip data (296 cases vs. 1,000 controls) and a replication study (1,360 cases vs. 3,553 controls) in the Korean population. Among 26 candidate single nucleotide polymorphisms (SNPs) tested in replication study, only a rare nonsynonymous SNP (rs4365796: c.1106C>T, p.Thr369Met) in the lymphoid enhancer binding factor 1 (LEF1) gene was very significantly associated with KD in patients younger than 6 months of age (odds ratio [OR], 3.07; p(combined) = 1.10 × 10⁻⁵), whereas no association of the same SNP was observed in any other age group of KD patients. The same SNP (rs4365796) in the LEF1 gene showed the same direction of risk effect in Japanese KD patients younger than 6 months of age, although the effect was not statistically significant (OR, 1.42; p = 0.397). This result indicates that the LEF1 gene may play an important role as a susceptibility gene specifically affecting KD patients younger than 6 months of age.

The clinicopathological features of solid pseudopapillary neoplasm of the pancreas and the application of LEF-1 in its diagnosis / 中华胰腺病杂志

Objective To analyze the application of clinicopathological features and LEF-1 in the diagnosis of solid pseudopapillary neoplasm of the pancreas (SPN).Methods Clinical and pathological data of 227 cases who were pathologically diagnosed as pancreatic SPN at Changhai Hospital from Jan 2000 to Dec 2015 were collected and analyzed.Immunochemical assay was used to detect the expression of LEF-1 in 132 cases of SPN, and the results were compared with β-catenin, which is most commonly used for diagnosing SPN.Results 81.9% of patients with SPN were female (186/227).Mean age at the onset was 34 years.Mean tumor size was 5.4 cm.48.5% tumors were localized in the pancreatic tail, and 33% in the head.46.3% tumors were cystic and solid, 42.3% were solid, and 11.4% were cystic.There were 2 cases of lymph node metastasis (0.9%), 15 cases of vascular tumor thrombus (6.6%), 14 cases of nerve invasion (6.2%), and 13 cases of adjacent organs invasion (5.7%) based on microscopic observations.Immunochemical analysis showed that 130 of 132 cases with SPN expressed LEF-1 with strong nuclear positivity, and the positivity rate was 98.5%.But no obvious expression of LEF-1 can be seen in normal pancreatic tissue and other pancreatic tumors.The specificity was 100%.The positivity of β-catenin expression in SPN was 96.6%(144/149), and β-catenin was positively expressed in only one case of acinar cell carcinoma.Tumors were completely removed by surgery in 165 cases, and the median follow-up was 51 months.By Oct 31, 2016, 162 patients (98.2%) survived, 5 had liver metastasis, and 1 had recurrence.Conclusions SPN is predominantly encountered in young female patients, and the clinical manifestations are not specific.LEF-1 can be used as a specific marker for the diagnosis and differentiation of SPN, which is more accurate than β-catenin.

Effects of ?-catenin-dependent LEF-1 isoforms on the biological behavior of HeLa cells / 西安交通大学学报(医学版)

Objective To study the effects of ?-catenin-dependent lymphoid enhancer factor(LEF-1) isoforms on biological behavior of HeLa cells.Methods ?-catenin-dependent LEF-1 genes were obtained by PCR from human lymphoid node cDNA library and inserted into pcDNA3.1/V5-His vector to construct the eukaryotic expression plasmid pcDNA3.1-F-LEF-1.Using lipofectamineTM 2000,the plasmid pcDNA3.1-F-LEF-1 was transfected into Hela cells.Then we screened the stable cell lines that expressed the truncated LEF-1 isoforms by G418 and identified the expression of target gene with Western blot.Then we analyzed the proliferation,apoptosis,cell clone formation and capability of tumor formation in vivo of transfected cell lines.Results We successfully constructed the ?-catenin-dependent LEF-1 eukaryotic expression plasmid and obtained the stable HeLa cell lines that expressed the full-length LEF-1 isoforms.The proliferation and capability of tumor formation in vivo of transfected cells were increased while apoptosis was decreased.Conclusion The overexpression of ?-catenin-dependent isoforms can stimulate the malignant biological behavior of HeLa cells.