Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA1) is the only viral protein consistently expressed in all EBV-associated malignancies, and play a critical role in the onset, progression, and/or maintenance of these tumors. Based on the signature changes at amino acid residue 487, EBNA1 is classified into five distinct subtypes: P-ala, P-thr, V-leu, V-val and V-pro. In the present study, the sequence variations of EBNA1 in EBV-associated gastric carcinoma (EBVaGC) and throat washing (TW) samples of healthy EBV carriers in Guangzhou, southern China, where nasopharyngeal carcinoma (NPC) is endemic, were analyzed by PCR and DNA sequencing. V-val subtype was the most predominant (53.6%, 15/28) in EBVaGC, followed by P-ala (42.9%, 12/28) and V-leu (32.1%, 9/28) subtypes. In TWs of healthy EBV carriers, V-val subtype was also predominant (85.7%, 18/21). The sequence variations of EBNA1 in EBVaGC were similar to those in TW of healthy EBV carriers (p>0.05), suggesting that the EBV strains in EBVaGC might originate from the viral strains prevalent within the background population. The predominance of V-val subtype in EBVaGC in Guangzhou was similar to that in EBVaGC in northern China and Japan, but was different from that in EBVaGC in America, suggesting that the variations of EBNA1 in EBVaGC represent geographic-associated polymorphisms rather than tumor-specific mutations. In addition, the EBNA1 variations in EBVaGC in gastric remnant carcinoma were also determined. V-leu subtype was detected in all 4 (100%) cases, although 2 cases occurred as mixed infection with P-ala subtype. This is different from the predominant V-val subtype in EBVaGC in conventional gastric carcinoma, suggesting that V-leu might be a subtype that adapts particularly well to the microenvironment within the gastric stump and enters the remnant gastric mucosa epithelia easily. This, to our best knowledge, is the first investigation of EBNA1 polymorphisms in EBVaGC from endemic area of NPC. 相似文献
Epstein-Barr virus (EBV) is associated with a subset of gastric carcinoma which was defined as EBV associated gastric carcinoma (EBVaGC). The proportion of EBVaGC in gastric remnant carcinoma (GRC) which occurs in the intact stomach five or more years after gastric surgery for benign disease is significantly higher than that in conventional gastric carcinoma (CGC). The infection of EBV in recurrent gastric carcinoma (RGC) with local anastomotic recurrence is poorly understood.
Methods
53 cases of GRC and 58 cases of RGC were analyzed for the presence of EBV, and the variants of EBV Encoded RNAs (EBER), EBV Nuclear Antigen 1 (EBNA1) and Latent Membrane Protein 1 (LMP1) gene in both groups were investigated.
Results
Thirteen (24.5%) out of 53 GRC cases and 3 (5.2%) out of 58 RGC cases were identified as EBVaGCs. In 17 paired RGC cases, only one case was classified as EBVaGC in both times specimen. Another one case was identified as EBVaGC in the primary gastroectomy specimen while the recurrent gastric cancer was not. The third EBVaGC in RGC was identified while the primary gastric cancer was not EBVaGC. In GRC and RGC cases, type 1, type F, EB-6m, V-val subtype, del-LMP1 were predominant type or variants, accounting for 10(76.9%) and 2(66.7%), 13(100%) and 3(100%), 13(100%) and 3(100%), 9(69.2%) and 3(100%), 12(92.3%) and 3(100%), respectively. However, Type C was the predominant type in GRC accounting for 9(69.2%) cases while type D was the predominant one accounting for 2(66.7%) cases in RGC.
Conclusions
The prevalence of EBVaGc in GRC and RGC was significantly different. The distributions of these variants were similar to each other in the two groups which indicated that there were no more aggressive EBV variants in EBVaGC in GRC compared with that in RGC. 相似文献
Latent membrane protein 2A (LMP2A), expressed in most Epstein-Barr virus (EBV)-associated malignancies, has been demonstrated to be responsible for the maintenance of latent infection and epithelial cell transformation. Besides, it could also act as the target for a CTL-based therapy for EBV-associated malignancies. In the present study, sequence variations of LMP2A in EBV-associated gastric carcinoma (EBVaGC) and healthy EBV carriers from Guangzhou, southern China, where nasopharyngeal carcinoma (NPC) is endemic, were investigated. Widespread sequence variations in the LMP2A gene were found, with no sequence identical to the B95.8 prototype. No consistent mutation was detected in all isolates. The immunoreceptor tyrosine-based activation motif (ITAM) and PY motifs in the amino terminus of LMP2A were strictly conserved, suggesting their important roles in virus infection; while 8 of the 17 identified CTL epitopes in the transmembrane region of LMP2A were affected by at least one point mutation, which may implicate that the effect of LMP2A polymorphisms should be considered when LMP2A-targeted immunotherapy is conducted. The polymorphisms of LMP2A in EBVaGC in gastric remnant carcinoma (GRC) were for the first time investigated in the world. The LMP2A sequence variations in EBVaGC in GRC were somewhat different from those in EBVaGC in conventional gastric carcinoma. The sequence variations of LMP2A in EBVaGC were similar to those in throat washing of healthy EBV carriers, indicating that these variations are due to geographic-associated polymorphisms rather than EBVaGC-associated mutations. This, to our best knowledge, is the first detailed investigation of LMP2A polymorphisms in EBVaGC in Guangzhou, southern China, where NPC is endemic. 相似文献
The KT tumor is a transplantable strain of a human Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC), established in severe combined immunodeficiency (SCID) mice, with which the cytokine expression of EBVaGC can be investigated without interference from the infiltrating lymphocytes. As a part of a high-density oligonucleotide array (GeneChip) analysis of EBVaGC, the interleukin-1beta (IL-1beta) gene was the only cytokine gene that showed markedly higher expression in the KT tumor cells than in two tumor strains of EBV-negative GC. The results were confirmed by Northern blotting, Western blotting, and enzyme-linked immunosorbent assay. Furthermore, we demonstrated a positive signal for IL-1beta mRNA in the carcinoma cells of a surgically resected EBVaGC, but not in EBV-negative GC, by in situ hybridization. In vitro, IL-1beta increased the cell growth of a GC cell line, TMK1. Thus, IL-1beta may act as an autocrine growth factor in EBVaGC. 相似文献
The relationship between the Filaggrin gene (FLG) rs2065955 polymorphism and susceptibility to Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) and EBV-negative gastric carcinoma (EBVnGC) was investigated in Shandong Province, China. We detected the FLG rs2065955 genotype and allele distribution by using PCR and restriction fragment length polymorphism (RFLP) in 64 EBVaGC, 82 EBVnGC, and 111 normal control samples. Immunohistochemistry was used to detect the level of FLG protein in 35 EBVaGC and 51 EBVnGC tumor tissues. Compared with normal controls, the genotype CC and allele C of FLG rs2065955 showed higher frequency in EBVaGC and EBVnGC. There was no significant difference between EBVaGC and EBVnGC in allele distribution of FLG rs2065955, but the genotype CC was found more frequently in EBVaGC than in EBVnGC. The risk of developing either EBVaGC or EBVnGC in genotype CC was higher than in other genotypes. Furthermore, genotype CC of FLG rs2065955 may contribute more to the risk of developing EBVaGC than EBVnGC. There was no significant difference in the expression level of FLG protein between EBVaGC and EBVnGC. In conclusion, the FLG rs2065955 polymorphism was significantly related to gastric carcinoma. Allele C of FLG rs2065955 could be a risk factor for EBVaGC or EBVnGC, while genotype CC of FLG rs2065955 was especially associated with EBVaGC.
We wished to learn whether the genomes of strains of EMB isolated from patients with infectious mononucleosis are consistently distinguishable from those of strains from Burkitt's lymphoma. The genome of a new transforming strains (FF41) of EBV isolated from saliva of a patient with uncomplicated infectious mononucleosis was compared with the DNA of B95-8, the only other available virus from mononucleosis. It had been found previously that B95-8 has a deletion of about 8 Md in the region of the physical map represented by the Eco RI C, Hind III D, and Bam HI I fragments. The W91 and HR-1 isolates for Burkitt's lymphoma are not deleted in this region and it had been proposed that additional information was characteristic of EBV isolates from Burkitt's lymphoma. By means of restriction enzyme analysis, blot hybridization experiments and molecular cloning of FF41 DNA we demonstrate that the deletion found in B95-8 is not present in the new mononucleosis isolate. The FF41 genome contains an extra 8 Md of DNA, represented by Bam HI fragments B', W' and I', which are located in a larger Eco RI C fragment. Thus the genome of this salivary isolate contains DNA that had previously been regarded to be unique to strains from Burkitt's lymphoma. It is therefore unlikely that major insertions or deletions in the EBV genome account for differences in disease manifestation following EBV infection. 相似文献
Incubation of the DNA of the B95-8 strain of Epstein-Barr virus [EBV (B95-8) DNA] with EcoRI, Hsu I, Sal I, or Kpn I restriction endonuclease yielded 8 to 15 fragments separable on 0.4% agarose gels and ranging in molecular weight from less than 1 to more than 30 x 10(6). Bam I and Bgl II yielded fragments smaller than 11 x 10(6). Preincubation of EBV (B95-8) DNA with lambda exonuclease resulted in a decrease in the Hsu I A and Sal I A and D fragments, indicating that these fragments are positioned near termini. The electrophoretic profiles of the fragments produced by cleavage of the DNA of the B95-8, HR-1, and Jijoye strains of EBV were each distinctive. The molecular weights of some EcoRI, Hsu I, and Sal I fragments from the DNA of the HR-1 strain of EBV [EBV (HR-1) DNA] and of EcoRI fragments of the DNA of the Jijoye strain of EBV were identical to that of fragments produced by cleavage of EBV (B95-8) DNA with the same enzyme, whereas others were unique to each strain. Some Hsu I, EcoRI, and Sal I fragments of EBV (HR-1) DNA and Kpn I fragments of EBV (B95-8) DNA were present in half-molar abundance relative to the majority of the fragments. In these instances, the sum of the molecular weights of the fragments was in excess of 10(8), the known molecular weight of EBV (HR-1) and (B95-8) DNA. The simplest interpretation of this finding is that each EBV (HR-1), and possibly also (B95-8), DNA preparation contains two populations of DNA molecules that differ in the arrangement of DNA sequences about a single point, such as has been described for herpes simplex virus DNA. Minor fragments could also be observed if there were more than one difference in primary structure of the DNAs. The data do not exclude more extensive heterogeneity in primary structure of the DNA of the HR-1 strain. However, the observation that the relative molar abundance of major and minor fragments of EBV (HR-1) DNA did not vary between preparations from cultures that had been maintained separately for several years favors the former hypothesis over the latter. 相似文献
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