PMID- 10476232
OWN - NLM
STAT- MEDLINE
DCOM- 19990923
LR  - 20131121
IS  - 0969-7128 (Print)
IS  - 0969-7128 (Linking)
VI  - 6
IP  - 4
DP  - 1999 Apr
TI  - 5-Azacytidine prevents transgene methylation in vivo.
PG  - 703-7
AB  - Retroviral sequence can silence transgene expression in vitro and in vivo. We 
      report that this effect can be efficiently prevented by in vivo administration of 
      the demethylating agent 5-azacytidine (aza-C). We engineered the U937 human cell 
      line with a retroviral vector consisting of the thymidine kinase suicide gene 
      (tk), which induces sensitivity to ganciclovir (gcv) and through an IRES 
      sequence, the bacterial beta-galactosidase gene (lacZ) as a marker gene. About 
      90% of the U937 cells expressed the transgene. By injecting the transduced U937 
      cells in severe combined immunodeficient disease (SCID) mice, we generated a 
      tumor which, during in vivo treatment with aza-C, maintained the high expression 
      of lacZ and tk genes at the baseline values. LacZ-positive cells in the tumour 
      masses after death was weak (1-2%) in the control group, while in mice treated 
      with aza-C it was maintained at 90%. The delay in tumour onset was significantly 
      longer when animals were treated with both aza-C and gcv (P < 0.0001) compared 
      with animals treated with gcv or with aza-C alone. The prevention of silencing 
      phenomena has important implications for gene therapy, because an efficient 
      transduction associated with appropriate drug therapy, might be a powerful 
      strategy for successful application of gene therapy protocols.
FAU - Di Ianni, M
AU  - Di Ianni M
AD  - Department of Clinical and Experimental Medicine, University of Perugia, Italy.
FAU - Terenzi, A
AU  - Terenzi A
FAU - Perruccio, K
AU  - Perruccio K
FAU - Ciurnelli, R
AU  - Ciurnelli R
FAU - Lucheroni, F
AU  - Lucheroni F
FAU - Benedetti, R
AU  - Benedetti R
FAU - Martelli, M F
AU  - Martelli MF
FAU - Tabilio, A
AU  - Tabilio A
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Gene Ther
JT  - Gene therapy
JID - 9421525
RN  - 0 (Antiviral Agents)
RN  - EC 2.7.1.21 (Thymidine Kinase)
RN  - M801H13NRU (Azacitidine)
RN  - P9G3CKZ4P5 (Ganciclovir)
SB  - IM
MH  - Animals
MH  - Antiviral Agents/administration & dosage
MH  - Azacitidine/*therapeutic use
MH  - DNA Methylation/*drug effects
MH  - Ganciclovir/administration & dosage
MH  - Gene Expression/drug effects
MH  - Genetic Therapy/*methods
MH  - Genetic Vectors/*administration & dosage/genetics
MH  - Humans
MH  - Lac Operon/genetics
MH  - Mice
MH  - Mice, SCID
MH  - Retroviridae/*genetics
MH  - Thymidine Kinase/genetics
MH  - U937 Cells
EDAT- 1999/09/07 00:00
MHDA- 1999/09/07 00:01
CRDT- 1999/09/07 00:00
PHST- 1999/09/07 00:00 [pubmed]
PHST- 1999/09/07 00:01 [medline]
PHST- 1999/09/07 00:00 [entrez]
AID - 10.1038/sj.gt.3300848 [doi]
PST - ppublish
SO  - Gene Ther. 1999 Apr;6(4):703-7. doi: 10.1038/sj.gt.3300848.