title: Expression patterns of non-coding spliced transcripts from human endogenous retrovirus HERV-H elements in colon cancer.
abstract: BACKGROUND
  Up-regulation of the most abundant H family human endogenous retrovirus (HERV-H), especially env-related transcripts, correlates with colon cancer. However, expression pattern of spliced non-coding transcripts of HERV-H is not clear.
  
  
  RESULTS
  In this study, expression of HERV-H spliced transcripts in colon cancer was investigated by a RT-PCR strategy using primers targeting the tRNA(His) primer-binding site and the R region in the 3' long terminal repeat (LTR), followed by cloning and sequencing of the amplicons. Sequences were then assigned to individual HERV-H loci by employing private nucleotide differences between loci. Different expression patterns of HERV-H spliced transcripts from distinct active elements were found in colon cancer cell lines HT29, LS 174T, RKO, SW480 and SW620. Furthermore, the expression patterns in SW480 and RKO were significantly changed by demethylation treatment. Interestingly, more HERV-H elements were found to be transcriptionally active in colon tumor tissues than in adjacent normal tissues (14 vs. 7).
  
  
  CONCLUSIONS
  This is the first research to study the character of expression of non-coding spliced transcripts of HERV-H elements in colon cancer. Expression patterns of HERV-H spliced transcripts differed among colon cancer cell lines and could be affected by genomic DNA methylation levels. More importantly, besides the commonly accepted view of up-regulation of HERV-H expression in colon tumor tissues, we found more active HERV-H loci in colon tumor as compared with adjacent normal tissues.
authors.affiliation: Cancer Institute, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
authors.forename: Qiaoyi
authors.initials: Q
authors.lastname: Liang
authors.forename: Zefeng
authors.initials: Z
authors.lastname: Xu
authors.forename: Rongzhen
authors.initials: R
authors.lastname: Xu
authors.forename: Lijun
authors.initials: L
authors.lastname: Wu
authors.forename: Shu
authors.initials: S
authors.lastname: Zheng
mesh_terms: D000236:Adenoma / Q000235:genetics; D017398:Alternative Splicing / Q000502:physiology; D001483:Base Sequence; D002277:Carcinoma / Q000235:genetics*; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000235:genetics*; D020077:Endogenous Retroviruses / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D019073:HT29 Cells; D006801:Humans; D008969:Molecular Sequence Data; D059368:RNA Isoforms / Q000235:genetics*; D022661:RNA, Untranslated / Q000235:genetics*
chemical_list: D059368:RNA Isoforms; D022661:RNA, Untranslated