title: Targeting bcl-2 by triplex-forming oligonucleotide--a promising carrier for gene-radiotherapy.
abstract: Triplex forming oligonucleotides (TFO) provide a promising tool for gene therapy. DNA damaging agents have been successfully coupled to TFOs and induce site-directed DNA damages. Here, we attempted to apply this antigen strategy using a TFO incorporated with a Conversion-electron-emitter, (99m)technetium, to target bcl-2 gene, the prototypical inhibitor of apoptosis. In the bcl-2 promoter region, we found two TFO binding sites which bind corresponding TFOs with very high specificity and affinity. Both partially and completely phosphorothioated TFOs form stable triplexes and significantly inhibit gene transcription in vitro. We also found that purine motif TFO with a thymidine opposite a thymidine interruption at the polypurine strand can form a stable triplex. In addition, (99m)technetium-conjugated TFOs were found to form a stable triplex and to inhibit bcl-2 gene transcription in vitro. Our results suggest a promising application of this triplex-forming oligonucleotide based Conversion-electron-emitter mediated gene radiotherapy in diseases related to bcl-2 overexpression.
authors.affiliation: Department of Nuclear Medicine, University of Ulm, Germany.
authors.forename: Changxian
authors.initials: C
authors.lastname: Shen
authors.forename: Dirk
authors.initials: D
authors.lastname: Rattat
authors.forename: Andreas
authors.initials: A
authors.lastname: Buck
authors.forename: Gerhard
authors.initials: G
authors.lastname: Mehrke
authors.forename: Bülent
authors.initials: B
authors.lastname: Polat
authors.forename: Hanno
authors.initials: H
authors.lastname: Ribbert
authors.forename: Holger
authors.initials: H
authors.lastname: Schirrmeister
authors.forename: Bettina
authors.initials: B
authors.lastname: Mahren
authors.forename: Christiane
authors.initials: C
authors.lastname: Matuschek
authors.forename: Sven N
authors.initials: SN
authors.lastname: Reske
mesh_terms: D019254:Genes, bcl-2; D015316:Genetic Therapy; D006367:HeLa Cells; D006801:Humans; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry*; D011401:Promoter Regions, Genetic; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors*; D013667:Technetium / Q000627:therapeutic use*; D014158:Transcription, Genetic / Q000187:drug effects*
chemical_list: D009841:Oligonucleotides; D019253:Proto-Oncogene Proteins c-bcl-2; D013667:Technetium