Leukocyte Cell-derived Chemotaxin 2 Gene Research Articles

Prognostic value of LECT2 and relevance to immune infiltration in hepatocellular carcinoma.

Background: Previous studies have shown that Leukocyte cell-derived chemotaxin2 (LECT2) is associated with the development of HCC. However, there are still no studies with a comprehensive analysis of the role of LECT2 in hepatocellular carcinoma (HCC). Methods: TCGA data sets were used to analyze the expression of LECT2 in HCC. In addition, the prognostic value of LECT2 in HCC was also investigated. DriverDBv3 was used to analyze the Mutation, CNV, and methylation profiles of LECT2. And, validated by immunohistochemistry in 72 HCC samples. The prognostic value of LECT2 and the correlation with clinicopathological features were analyzed. The GO/KEGG enrichment analysis of LECT2 co-expression and gene set enrichment analysis (GSEA) was performed using the R software package. The PPI interaction network was constructed by Search Tool for the Retrieval of Interacting Genes (STRING) database. Immune infiltration was estimated by the XCELL, TIMER, QUANTISEQ, MCPCOUNTER, EPIC, CIBERSORT abs and CIBERSORT algorithms, and Spearman was used to analyzing their correlation with LECT2. Moreover, we analyzed the correlation of LECT2 expression with immune checkpoint molecules and HLA genes. Finally, we analyzed the IC50 values of six chemotherapeutic drugs by the pRRophetic package. Results: Reduced LECT2 expression levels found in HCC patients. Moreover, decreased levels of LECT2 were associated with poor overall survival, disease-free survival, disease-specific survival, and progression-free survival. Besides, methylation was significantly associated with LECT2 expression. The functional enrichment analysis revealed that LECT2 may affect HCC progression through various pathways such as JAK/STAT signaling pathway, cell cycle, and pathways in cancer. Additionally, the results showed that LECT2 expression was negatively correlated with immune infiltration of B cells, Neutrophil, Monocyte, Cancer-associated fibroblast, and Myeloid dendritic cell, and positively correlated with T cell CD8+ naive, Endothelial cell, and Hematopoietic stem cell. LECT2 expression was negatively correlated with multiple immune checkpoint molecules and HLA genes. Chemosensitivity analysis showed that chemosensitivity was lower in the LECT2 high expression group. We validated the prognostic value of LECT2 and analysis of clinicopathological features showed a lower TNM stage in the group with high expression of LECT2. Conclusion: Low expression of LECT2 in HCC is closely associated with poor prognosis, LECT2 may have potential clinical applications due to its unique immunological effects.

Transcriptional regulation of chicken leukocyte cell-derived chemotaxin 2 in response to toll-like receptor 3 stimulation.

ObjectiveLeukocyte cell-derived chemotaxin 2 (LECT2) is associated with several physiological processes including inflammation, tumorigenesis, and natural killer T cell generation. Chicken LECT2 (chLECT2) gene was originally identified as one of the differentially expressed genes in chicken kidney tissue, where the chickens were fed with different calcium doses. In this study, the molecular characteristics and gene expression of chLECT2 were analyzed under the stimulation of toll-like receptor 3 (TLR3) ligand to understand the involvement of chLECT2 expression in chicken metabolic disorders.MethodsAmino acid sequence of LECT2 proteins from various species including fowl, fish, and mammal were retrieved from the Ensembl database and subjected to Insilco analyses. In addition, the time- and dose-dependent expression of chLECT2 was examined in DF-1 cells which were stimulated with polyinosinic:polycytidylic acid (poly [I:C]), a TLR3 ligand. Further, to explore the transcription factors required for the transcription of chLECT2, DF-1 cells were treated with poly (I:C) in the presence or absence of the nuclear factor κB (NFκB) and activated protein 1 (AP-1) inhibitors.ResultsThe amino acid sequence prediction of chLECT2 protein revealed that along with duck LECT2 (duLECT2), it has unique signal peptide different from other vertebrate orthologs, and only chLECT2 and duLECT2 have an additional 157 and 161 amino acids on their carboxyl terminus, respectively. Phylogenetic analysis suggested that chLECT2 is evolved from a common ancestor along with the actinopterygii hence, more closely related than to the mammals. Our quantitative polymerase chain reaction results showed that, the expression of chLECT2 was up-regulated significantly in DF-1 cells under the stimulation of poly (I:C) (p<0.05). However, in the presence of NFκB or AP-1 inhibitors, the expression of chLECT2 is suppressed suggesting that both NFκB and AP-1 transcription factors are required for the induction of chLECT2 expression.ConclusionThe present results suggest that chLECT2 gene might be a target gene of TLR3 signaling. For the future, the expression pattern or molecular mechanism of chLECT2 under stimulation of other innate immune receptors shall be studied. The protein function of chLECT2 will be more clearly understood if further investigation about the mechanism of LECT2 in TLR pathways is conducted.

Characterization of the LECT2 gene and its protective effects against microbial infection via large lymphocytes in Lampetra japonica

Leukocyte cell-derived chemotaxin 2 (LECT2) is a multifunctional protein of the innate immune system that defends against bacterial infections and chemotactic activity. However, its precise function in lamprey remains unclear. In this study, a novel LECT2 gene was first cloned from Lampetra japonica. The full-length cDNA sequence of L-LECT2 consists of a 606-bp ORF encoding a protein of 201 amino acid residues. L-LECT2 has greater than 50% sequence identity with its homologs in jawed vertebrates. FACS and immunohistochemistry assays were used to determine that the L-LECT2 protein was primarily distributed in the intestines and supraneural body tissues of lamprey, also marginally detectable in leukocytes. However, the expression of L-LECT2 was differentially upregulated in the intestines and heart after treatment with LPS. The recombinant L-LECT2 resulted in significant promoting migration of the leukocytes in vitro. Our data demonstrate that L-LECT2 treatment could enhance phagocytosis in lamprey large lymphocytes. Thus, our results suggest that LECT2 can modulate the host defense in lamprey and mediate antibacterial protection against E.coli through large lymphocytes.

Mixed leukocyte cell-derived chemotaxin 2 and amyloid A renal amyloidosis in a Kazakh-German patient.

Leukocyte cell-derived chemotaxin 2 (LECT2)-related amyloidosis (ALECT2) constitutes a subtype of systemic amyloidosis affecting the kidney. This is the first case describing mixed ALECT2 and Amyloid A renal amyloidosis in a Kazakh-German patient. Genetic analysis shows a polymorphism in the LECT2 gene and a homozygous mutation in the SAA1 gene. Notably, our patient has a body mass index of 61 kg/m2 and a pathological glucose tolerance test. ALECT2 was found in certain ethnic groups with a high incidence of diabetes. In our case, morbid obesity may have played a significant role in clinical manifestation of ALECT2 amyloidosis.

Inhibition of VEGF165/VEGFR2-dependent signaling by LECT2 suppresses hepatocellular carcinoma angiogenesis.

Hepatocellular carcinoma (HCC) relies on angiogenesis for growth and metastasis. Leukocyte cell-derived chemotaxin 2 (LECT2) is a cytokine and preferentially expressed in the liver. Previous studies have found that LECT2 targets to both immune and tumor cells to suppress HCC development and vascular invasion. Although LECT2 did not affect HCC cells growth in vitro, it still suppressed HCC xenografts growth in immune-deficient mice, suggesting other cells such as stroma cells may also be targeted by LECT2. Here, we sought to determine the role of LECT2 in tumor angiogenesis in HCC patients. We found that LECT2 expression inhibited tumor growth via angiogenesis in the HCC xenograft model. Specifically, we demonstrated that recombinant human LECT2 protein selectively suppressed vascular endothelial growth factor (VEGF)165-induced endothelial cell proliferation, migration, and tube formation in vitro and in vivo. Mechanistically, LECT2 reduced VEGF receptor 2 tyrosine phosphorylation and its downstream extracellular signal-regulated kinase and AKT phosphorylation. Furthermore, LECT2 gene expression correlated negatively with angiogenesis in HCC patients. Taken together, our findings demonstrate that LECT2 inhibits VEGF165-induced HCC angiogenesis through directly binding to VEGFR2 and has broad applications in treating VEGF-mediated solid tumors.

Characterization of the LECT2 gene and its associations with resistance to the big belly disease in Asian seabass

Leukocyte cell-derived chemotaxin-2 (LECT2) is an important protein of the innate immune system for the defense against bacterial infection. We cloned and characterized the LECT2 gene from Asian seabass (Lates calcarifer). Its complete cDNA consisted of an open reading frame of 459 bp encoding a protein of 152 amino acids. The genomic DNA sequence of this gene consists of four exons and three introns. Quantitative real-time PCR revealed that the LECT2 gene was expressed predominantly in liver while its expression was moderate in spleen and heart, and weak in other tissues. The LECT2 transcript was up-regulated in the kidney, spleen and liver in response to a challenge with a pathogenic bacterium Vibrio harveyi. In addition, we identified three single nucleotide polymorphisms (SNPs) in the LECT2 gene, and found significant associations between these polymorphisms and resistance to the big belly disease. These results suggest that the LECT2 gene play an important role in resistance to bacterial pathogens in fish. The SNP markers in the gene associated with the resistance to bacterial pathogens may facilitate selecting Asian seabass resistant to bacterial diseases.

Identification and expression analysis of the leukocyte cell-derived chemotaxin-2 (LECT2) gene in duck (Anas platyrhynchos)

Leukocyte cell-derived chemotaxin 2 (LECT2), first identified as a chemotactic factor, is involved in the regulation of liver regeneration, carcinogenesis, and natural killer T-cell homeostasis in mammals. The function of LECT2 in the duck remains unclear, however. A suppression subtractive cDNA library was constructed from the livers of 3-day-old ducklings treated with duck hepatitis virus type I (DHV-1). A total of 66 expressed sequence tags (ESTs) were identified in the libraries. Among the novel gene fragments identified was the LECT2 gene. Full-length duck LECT2 (duLECT2) complementary DNA (cDNA) was obtained using the reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of the cDNA ends (RACE). The cDNA consisted of a 50 nucleotide 5′ untranslated region (UTR), an 84 nucleotide 3′ UTR, and a 1020 nucleotide open reading frame encoding a single protein of 339 amino acids. In agreement with a previously reported LECT2 sequence, the predicted amino acid sequence contains characteristic phosphorylation and N-glycosylation sites. DuLECT2 is highly similar to LECT2 genes from other vertebrates. Phylogenetic analysis demonstrated that the LECT2 gene has been highly conserved throughout vertebrate evolution. RT-PCR analyses revealed that duLECT2 mRNA is widely expressed in healthy tissues. They also showed that duLECT2 mRNA is significantly up-regulated in the liver and spleen following injection with DHV-1 or polyriboinosinic polyribocytidylic acid (poly I:C), peaking 4 or 12h post-challenge in the liver and spleen, respectively, and afterwards gradually returning to normal. Our findings suggest that duLECT2 contributes to the innate immune response against viral infections.

Cloning, characterization and expression of the LECT2 gene in grass carp

An expressed sequence tag of grass carp leukocyte cell-derived chemotaxin 2 (LECT2) gene was screened from an established intestinal cDNA library. Rapid amplification of cDNA ends gave rise to a full-length LECT2 cDNA (gcLECT2) with a complete open-reading frame of 474 bp, encoding 158 amino acids about 17.9 kDa. Homology search and sequence alignment showed that this deduced protein sequence shared a high identity with LECT2 from other vertebrates. Western blotting indicated immunological cross-reactivity occurs between grass carp and human LECT2 protein. This gcLECT2 genomic sequence is 1,868 bp in size, which consists of five exons and four introns. Real-time quantitative PCR analysis revealed that gcLECT2 gene is ubiquitously expressed in different tissues of healthy grass carp including brain, gut, liver, spleen, kidney, muscle and heart, while the expression levels were significantly increased in liver and spleen followed by Aeromonas salmonicida infection. 992 bp 5'-flanking region sequence was cloned and analyzed, where one CAAT box and one GC island were found. Our results showed that the LECT2 is suggested to be most possibly involved in the grass carp's immune response.

The prognosic value of the downregulation of leukocyte cell–derived chemotaxin 2 gene of hepatocellular carcinoma.

10559 Background: Vascular invasion of hepatocellular carcinoma (HCC) is the major contribution of high recurrence and poor survival. In our previous study, we used suppression subtractive hybridization and cDNA microarray to identify leukocyte cell-derived chemotaxin 2 (LECT2) as one of the 20 differentially-expressed genes between vascular-invasion, and non-vascular invasion of HCC. We also found LECT2 gene expression level was correlated with inhibitory effect of invasion ability of hepatoma cells through gene over-expression and knockdown experiments. The purpose of this study is to identify the relationship of gene expression level of LECT2, and clinicopathologic outcome in human HCC. Methods: 127 patients with primary, unifocal HCC were included. Archives HCC tumor tissue samples were used after approval by institutional review board and written informed consent. RT-PCR and western blot were used to measure LECT2 gene and protein expression level of HCC. The correlation with clinicopathologic outcom...

Molecular cloning of leukocyte cell-derived chemotaxin 2 in rainbow trout

In humans, leukocyte cell-derived chemotaxin 2 (LECT2) is a 16 kDa chemotactic protein that consists of 133 amino acids and three intramolecular disulphide bonds. Although it was originally demonstrated to have a chemotactic function in vitro, recent data sustain a further multifunctional role of LECT2 that extends from cell growth, differentiation, damage/repair process and carcinogenesis to autoimmune diseases. The in vivo function of LECT2 protein still remains obscure. In order to study the phylogeny of LECT2, a full-length cDNA clone of LECT2 gene, 720 bp in size, was isolated in rainbow trout ( Oncorhynchus mykiss). Its deduced amino acid sequence of 156 residues, presents 40, 45 and 61% overall identity to human, mouse and carp LECT2 proteins, respectively. In contrast to mammalian LECT2 protein, trout LECT2 protein reveals two potential N-glycosylation sites. Phylogenetic analysis shows that trout LECT2 is clustered with the known homologous proteins. Trout LECT2 mRNA is predominately expressed in liver and spleen, showing lower expression in kidney, intestine, heart and brain.

Molecular Cloning, Structural Characterization, and Chromosomal Mapping of the Human LECT2 Gene

We originally isolated LECT2 (leukocyte cell-derived chemotaxin 2) as a 16-kDa secreted protein having a human neutrophil chemotactic activity, then cloned human and bovine LECT2 cDNAs and demonstrated the liver-specific expression of the protein. LECT2 is thought to be a multifunctional protein, because it was recently found to be identical to chondromodulin-II, a growth stimulator of chondrocyte cells. We report here the cloning and the structural analysis of the human LECT2 gene. The gene spans approximately 8 kb and consists of four exons and three introns. Primer extension analysis revealed that several transcription initiation sites occur within 70–230 nucleotides upstream of the translation initiation codon. Several transcriptional control sequences relevant to the liver-specific expression have been identified at the 5′ untranslated region of the human LECT2 gene. The human LECT2 gene was mapped to chromosome 5q31.1–q32 by fluorescencein situhybridization. This region contains a cluster of cytokine genes including IL-4, IL-5, and IL-9.