lactoferrin and Nasopharyngeal-Carcinoma

It is reported that LTF had a radiation resistance effect, and its expression in nasopharyngeal carcinoma (NPC) was significantly down-regulated. However, the mechanism of down-regulated LTF affecting the sensitivity of radiotherapy has remained elusive.. We re-analyzed the microarray data GSE36972 and GSE48503 to find differentially expressed genes (DEGs) in NPC cell line 5-8 F transfected with LTF or vector control, and the DEGs between radio-resistant and radio-sensitive NPC cell lines. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment and protein-protein interaction network (PPI) analysis of DEGs were performed to obtain the node genes. The target genes of miR-214 were also predicted to complement the mechanism associated with radiotherapy resistance because it could directly target LTF.. This study identified 1190 and 1279 DEGs, respectively. GO and KEGG analysis showed that apoptotic process and proliferation, PI3K-Akt signaling pathway were significantly enriched pathways. Four nodes (DUSP1, PPARGC1A, FOS and SMARCA1) associated with LTF were screened. And 42 target genes of miR-214 were cross-linked to radiotherapy sensitivity.. The present study demonstrates the possible molecular mechanism that the down-regulated LTF enhances the radiosensitivity of NPC cells through interaction with DUSP1, PPARGC1A, FOS and SMARCA1, and miR-214 as its superior negative regulator may play a role in regulating the radiotherapy effect.

Topics: Cell Line, Tumor; Computational Biology; Databases, Genetic; Down-Regulation; Humans; Lactoferrin; MicroRNAs; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Protein Interaction Maps; Radiation Tolerance; X-Rays

Topics: Autoantigens; Fatty Acid-Binding Proteins; Glycoproteins; Humans; Immunity, Innate; Lactoferrin; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Phosphoproteins; Proteins

Lactotransferrin (LTF), also known as lactoferrin, is a key component of innate immune defense. We previously reported that LTF was downregulated in nasopharyngeal carcinoma (NPC) and could suppress NPC cell proliferation. However, the relevance of the relationship between LTF expression and NPC clinical outcome has not been reported. This study aims to assess the possible correlations between LTF expression and clinical parameters and its potential prognostic predictive ability in the outcomes of patients with NPC. Complementary DNA (cDNA) microarray, quantitative real-time PCR (qRT-PCR), and immunohistochemistry (IHC) results suggested that LTF expression was significantly downregulated in NPC tissues compared to non-NPC tissues. LTF was negatively correlated with lymph node metastasis (P = 0.042), T stage (P < 0.001), clinical tumor-node-metastasis (TNM) stage (P = 0.022), and EBV-encoded RNA 1 (EBER-1) expression (r = -.167, P = 0.016). A survival analysis of 108 patients with NPC revealed that positive expression of LTF could predict a good prognosis [disease-free survival (DFS): P = 0.043, overall survival (OS): P = 0.040]. Multivariable analysis revealed that LTF could independently predict prognosis (DFS: HR = 0.414, P = 0.003; OS: HR = 0.309, P = 0.005). These observations indicated that LTF is a potential prognostic factor of NPC.

Topics: Adolescent; Adult; Aged; Biomarkers, Tumor; Carcinoma; Cell Proliferation; Disease-Free Survival; Female; Gene Expression Regulation, Neoplastic; Humans; Lactoferrin; Lymphatic Metastasis; Male; Middle Aged; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Prognosis

LTF (lactotransferrin, also known as lactoferrin) is a key component of innate immune defense. It has recently been found to have anti-tumor and anti-metastatic activity in different cancers. We previously reported LTF to be the most significantly downregulated gene in nasopharyngeal carcinoma (NPC) specimens relative to normal nasopharyngeal epithelial tissues, and it was also negatively associated with the progression and metastasis of NPC. However, the mechanism underlying this remains unclear. In the current study, we revealed that LTF can suppress 3-phosphoinositide-dependent protein kinase 1 expression via the mitogen-activated protein kinase/c-Jun pathway and thus repress AKT signaling. We also showed that LTF interacts with keratin 18 (K18) and so blocks the formation of the K18-14-3-3 complex, leading to downregulation of K18-mediated AKT activation. Thus, LTF suppresses AKT signaling by two separate mechanisms, leading to inhibition of NPC tumorigenesis. This is the first report on the tumor suppressive effects of LTF through repression of AKT signaling in NPC. It suggests that both LTF and AKT signaling merit further study in the field of NPC research.

Topics: 14-3-3 Proteins; Adult; Aged; Animals; Biomarkers, Tumor; Carcinoma; Cell Line, Tumor; Cell Proliferation; Exonucleases; Exoribonucleases; Female; Gene Expression; Humans; Lactoferrin; Male; Mice; Middle Aged; Mitogen-Activated Protein Kinases; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Neoplasm Invasiveness; Neoplasm Staging; Protein Binding; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-akt; Pyruvate Dehydrogenase Acetyl-Transferring Kinase; Signal Transduction

Lactotransferrin (LTF) is a component of the nonspecific immune system, having antimicrobial properties against bacteria, fungi, and several viruses. The gene coding for LTF is polymorphic, with the occurrence of several common alleles in the general population. Our previous study found that LTF inhibited nasopharyngeal carcinoma (NPC) cell proliferation in vitro and in vivo. To better understand one possible mechanism of LTF-mediated antitumor activity in NPC cells, in the present study, we investigated the distribution of LTF gene polymorphisms (rs1126477, rs1126478, rs2073495, and rs9110) in NPC and revealed whether these polymorphisms were associated with LTF gene expression. It was found that rs2073495 and rs9110 were correlated significantly with NPC. The frequency of CC genotype was higher and GG or TT genotype was lower, in NPC patients compared with that in the control group (P < 0.05, χ(2) = 8.73 and 9.33, respectively). CC genotype is the risk factor for NPC. Haplotype analyses indicated that NPC patients had lower rate of 'A-G-G-T' haplotype (constructed with rs1126477, rs1126478, rs2073495, and rs9110) compared with controls (P = 4.12 × 10(-6) < 0.001, χ(2) = 21.25). The population with 'A-G-G-T' haplotype had 0.322-fold risk to be NPC. The expression of LTF gene was high in NPC tissues and control tissues with 'A-G-G-T' haplotype compared with these without its. These findings suggested that rs2073495 and rs9110 could play important roles in NPC physiological processes.

Topics: Blotting, Western; Carcinoma; Female; Genetic Predisposition to Disease; Haplotypes; Humans; Lactoferrin; Male; Middle Aged; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Polymorphism, Single Nucleotide; Reverse Transcriptase Polymerase Chain Reaction; Risk Factors

Lactoferrin (LF) is a multifunctional glycoprotein that plays an important role in native immune defense against infections, including human herpetic viruses, such as cytomegalovirus and herpes simplex virus types 1 and 2. However, its anti-Epstein-Barr virus (EBV, a γ-herpesvirus) function has not been reported in the literature. EBV is widespread in all human populations and is believed to be linked to tumorigenesis, such as lymphomas and nasopharyngeal carcinoma (NPC). We previously reported that LF expressed a significantly lower level in NPC tissues and was a likely tumor suppressor. Since EBV infection is a major carcinogen of NPC development, we investigated the effect of LF on EBV infection and found that LF could protect human primary B lymphocytes and nasopharyngeal epithelial cells from EBV infection, but had no effect on EBV genome DNA replication. LF prevented EBV infection of primary B cells mediated by its direct binding to the EBV receptor (CD21) on the B-cell surface. Tissue array immunohistochemistry revealed that LF expression was significantly downregulated in NPC specimens, in which high EBV viral capsid antigen-IgA levels were observed. These data suggest that LF may inhibit EBV infection and that its downregulation could contribute to NPC development.

Topics: Antigens, Viral; B-Lymphocytes; Capsid Proteins; Carcinoma; Cell Line, Tumor; Cells, Cultured; DNA Replication; DNA, Viral; Epithelial Cells; Epstein-Barr Virus Infections; Herpesvirus 4, Human; Humans; Immunoglobulin A; Lactoferrin; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Nasopharynx; Virus Replication

The lactoferrin (LTF) gene, located at 3p21.3, behaves like a tumor suppressor gene in diverse tumors. To elucidate the exact role of LTF in NPC, we first detected its expression level in seven NPC cell lines by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). The results showed the mRNA level of LTF was nearly undetectable in all the seven NPC cell lines, while it could be detected in chronic nasopharyngitis tissues. Subsequently, we used methylation-specific PCR (MSP), microsatellite assay, PCR-single-strand conformation polymorphism (PCR-SSCP) and sequencing methods to examine the promoter methylation, loss of heterozygosity (LOH) and gene mutation of LTF in NPC cell lines respectively. Consequently, we found that 100% (7 of 7) of NPC cell lines were methylated in LTF promoter, only one cell line (14%, 1 of 7) had LOH and gene mutation of LTF, respectively, while LTF exhibited re-expression in all cell lines after 5-aza-dC treatment, indicating promoter methylation should be the key mechanism causing LTF downregulation in NPC cell lines. Furthermore, patched methylation assay confirmed that promoter methylation could down-regulate LTF gene expression in NPC cells. Finally, we investigated the function of LTF in NPC cell lines by gene transfection. Restoration of LTF expression in NPC cells resulted in blockage of cell cycle progression, significant inhibition of cell growth and a reduced colony-formation capacity in vitro and obviously weaker tumor formation potential in vivo. In conclusion, our data indicate LTF may participate in NPC carcinogenesis as a negative effector, that is, a tumor suppressor gene.

Topics: Animals; Base Sequence; Carcinoma; Cell Line, Tumor; Cell Proliferation; DNA Methylation; DNA Mutational Analysis; Female; G1 Phase; Humans; Lactoferrin; Loss of Heterozygosity; Male; Mice; Mice, Nude; Molecular Sequence Data; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Neoplasm Transplantation; Promoter Regions, Genetic; Recombinant Proteins; Transcription, Genetic; Tumor Burden