[Influence of selenium-rich rice on transformation of umbilical blood B lymphocytes by Epstein-Barr virus and Epstein-Barr virus early antigen expression].

BACKGROUND & OBJECTIVE: Selenium (Se), an antioxidant, is an essential trace element to human body. It can be used as an anti-aging agent and a tumor cell proliferation inhibitor. To further investigate the effect of selenium in cancer prevention, the authors observed the influence of Se-rich rice extract on the transformation of umbilical blood B lymphocytes stimulated by Epstein-Barr virus (EBV) and expression of EBV early antigen(EBV-EA) in Raji cells. METHODS: (1) Se-rich rice and general rice extract (dilution of 1:4 or 1:8) were added to mixture of EBV, and then umbilical blood mononuclear cells were added. Lymphoblasts transformation test was then performed. The inhibition rate of B lymphocytes transformation was calculated. (2) Raji cells stimulated by butyrate and croton oil were incubated with Se-rich rice extract. The EBV-EA positive expression rate and the inhibition rate were counted using indirect immunological flurescence method. RESULTS: The transformation of umbilical blood B lymphocytes stimulated by EBV was significantly inhibited by Se-rich rice extract at a concentration of 0.11 g/ml (1:8 diluted). The inhibition rate was 83.4% (P < 0.01), which was significantly higher than that of the control rice (63.1%) (P < 0.05). Se-rich rice extract showed significant inhibition on EBV-EA in Raji cells. As the extract concentration was at 0.016 microgram/ml, 0.078 g/ml, and 0.388 microgram/ml, the inhibition rates of EA were 2.85%, 12.88%, and 20.75%, respectively. CONCLUSION: The transformation of umbilical blood B lymphocytes stimulated by EB virus and expression of EBV-EA in Raji cells may be significantly inhibited by Se-rich rice extract, suggesting that Se-rich rice can be used for preventing nasopharyngeal carcinoma.

[Molecular mechanisms of tumorgenesis and metastasis in nasopharyngeal carcinoma cell sublines].

BACKGROUND & OBJECTIVE: The authors have selected three different biological character sublines, including 5-8F (the highest tumorigenic and metastatic ability), 6-10B(the lowest tumorigenicity and lack of metastatic ability), and 13-9B(lack of tumorigenic ability), from colony lines of nasopharyngeal carcinoma cell line(SUNE-1). The aim of this study was to determine the molecular mechanisms of different biological character of SUNE-1 and its three sublines from two aspects of genetic and virology. METHOD: 1. Amplifying Epstein-Barr virus(EBV) BamHI W fragment by PCR. 2. Determining the expression of latent membrane protein1(LMP1) of EBV in the sublines using in situ hybrization. 3. Molecular cytogenetic analysis of the cell line and sublines by comparative genomic hybridization (CGH). RESULTS: 1. There was EBV BamHI W fragment in SUNE-1 and its three sublines. 2. Expression of LMP1 was observed in the SUNE-1 and its three sublines, and their expression intensity was identical. 3. There were DNA copy number gains on chromosomes 1, 2p, 3, 4, 5p, 6, 7, 9, 10q, 11, 12q, 13q, and 18q as well as loss on 22q in the SUNE-1 cell line; DNA copy number gains on chromosomes 3p, 7q, 8q, 9q, and 10q were observed in 5-8F subline; DNA copy number loss on few chromosomes, but no DNA copy number gain was observed in the 6-10B and 13-9B sublines. CONCLUSION: There were expression of EBV and different genetic changes in the SUNE-1 and its three sublines. It is suggesting that the different biological character tumorgenesis and metastasis of nasopharyngeal carcinoma cell sublines may be due to genetic changes; and EBV infection may play an important role in keeping the malignant phenotypic of nasopharyngeal carcinoma.

Genome-wide scan for familial nasopharyngeal carcinoma reveals evidence of linkage to chromosome 4.

Nasopharyngeal carcinoma (NPC) occurs with high frequency in Asian populations, especially among people of Cantonese ancestry. In areas with high incidence, NPC clusters in families, which suggests that both geography and genetics may influence disease risk. Although the HLA-Bw46 locus is associated with increased risk of NPC, no predisposing genes have been identified so far. Here we report the results of a genome-wide search carried out in families at high risk of NPC from Guangdong Province, China. Parametric analyses provide evidence of linkage to the D4S405 marker on chromosome 4 with a logarithm of odds for linkage (lod) score of 3.06 and a heterogeneity-adjusted lod (hlod) score of 3.21. Fine mapping with additional markers flanking D4S405 resulted in a lod score of 3.54 and hlod score of 3.67 for the region 4p15.1-q12. Multipoint nonparametric linkage analysis gives lod scores of 3.54 at D4S405 (P = 5.4 x 10(-5)) and 4.2 at D4S3002 (P = 1.1 x 10(-5)), which is positioned 4.5 cM away from D4S405. When Epstein Barr virus antibody titer was included as a covariate, the lod scores reached 4.70 (P = 2.0 x 10(-5)) and 5.36 (P = 4.36 x 10(-6)) for D4S405 and D4S3002, respectively. Our findings provide evidence of a major susceptibility locus for NPC on chromosome 4 in a subset of families.