ABSTRACT
In the present study, the mechanism by which carboxyl terminal activating region 3 (CTAR3) of latent membrane protein 1 (LMP1), encoded by the EpsteinBarr virus, regulated cell proliferation and protein expression was investigated in the nasopharyngeal epithelial cell line NP69. The deletion mutant LMP1 (LMP1Δ232351; amino acid residues including 232351 codons in CTAR3 deleted) was generated by polymerase chain reaction. An NP69LMP1Δ232351 cell line was established by retroviral infection. Finally, cell proliferation and protein expression of NP69 cells expressing LMP1Δ232351 were examined using a cell growth curve and western blot analysis. The results demonstrated: i) The proliferation of NP69LMP1Δ232351 cells was significantly decreased compared with cells expressing wild type LMP1 (LMP1WT; n=3; P<0.05); ii) 17 proteins exhibited differential protein expression (>2fold change) in NP69LMP1Δ232351 cells compared with NP69LMP1WT cells; and iii) LMP1WT was involved in activating the Janus kinase 3 (JAK3) promoter and regulating the expression of JAK3 protein, while LMP1Δ232351 was almost defective in ability to activate the JAK promoter. These results suggested that LMP1CTAR3 may be an important functional domain for regulating cell proliferation and protein expression in nasopharyngeal epithelial cells.
Subject(s)
Herpesvirus 4, Human/metabolism , Viral Matrix Proteins/chemistry , Viral Matrix Proteins/metabolism , Cell Line, Tumor , Cell Proliferation , Heterogeneous-Nuclear Ribonucleoproteins/metabolism , Humans , Janus Kinase 3/metabolism , Plasmids/metabolism , Promoter Regions, Genetic/genetics , Protein Domains , Proton-Motive Force , Reproducibility of Results , Signal Transduction , Structure-Activity Relationship , Transcription, GeneticABSTRACT
In the present study, the interaction of proteins in the microenvironment of gastric mucosal atypical hyperplasia was analyzed. The stromata of normal gastric mucosa (NGM) and gastric mucosal atypical hyperplasia (GMAH) tissues were purified with laser capture microdissection (LCM). The differentially expressed GMAH proteins of the NGM and GMAH tissues were identified by quantitative proteomic techniques with isotope labeling. The cross-talk between differentially expressed proteins in NGM and GMAH tissues was then analyzed by bioinformatics. There were 165 differentially expressed proteins identified from the stromata of NGM and GMAH tissues. Among them, 99 proteins were upregulated and 66 were downregulated in GMAH tissue. The present study demonstrated that these proteins in gastric mucosal atypical hyperplasia were involved in cancer-associated signaling pathways, including the p53, mitogen-activated protein kinase (MAPK), cell cycle and apoptosis signaling pathways, and were involved in cellular growth, cellular proliferation, apoptosis and the humoral immune response. The results of the present study suggest that the 165 differentially expressed proteins, including S100 calcium-binding protein A6 (S100A6) and superoxide dismutase 3 (SOD3) in the microenvironment of gastric mucosal atypical hyperplasia, are involved in the p53, MAPK, cell cycle and apoptosis signaling pathways, and serve a function in the pathogenesis of gastric cancer.
