title: Isolation of cancer-specific chimeric transcripts induced by hypomethylation of the LINE-1 antisense promoter.
abstract: The antisense promoter of human LINE-1 (L1) retroelements can direct transcription of adjacent unique genomic sequences generating chimeric RNAs, which can perturb transcription of neighbouring genes. As L1 elements constitute 17% of the human genome, chimeric transcription is potentially widespread, but the extent to which this occurs is largely unknown. Using a genome-wide screen we have isolated novel chimeric transcripts that are unique to breast cancer cell lines, primary tumours and colon cancer cells. Expression of the cancer-specific chimeric transcripts can be induced in non-malignant breast epithelial cells by the demethylating drug 5-azacytidine. These findings indicate that loss of L1 methylation in cancer cells is linked to the expression of L1-chimeric transcripts which may therefore constitute a useful set of markers of malignancy.
authors.affiliation: Wolfson Centre for Stem Cells, Tissue Engineering and Modelling (STEM), Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK.
authors.forename: Hazel A
authors.initials: HA
authors.lastname: Cruickshanks
authors.forename: Cristina
authors.initials: C
authors.lastname: Tufarelli
mesh_terms: D001374:Azacitidine / Q000494:pharmacology; D001940:Breast / Q000166:cytology; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D003110:Colonic Neoplasms / Q000235:genetics* / Q000473:pathology; D019175:DNA Methylation / Q000187:drug effects; D005260:Female; D006801:Humans; D020084:Long Interspersed Nucleotide Elements / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000302:isolation & purification*; D012334:RNA, Neoplasm / Q000096:biosynthesis / Q000302:isolation & purification*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D012333:RNA, Messenger; D012334:RNA, Neoplasm; D001374:Azacitidine