| Title : Use of the ornithine decarboxylase promoter to achieve N-MYC-mediated overexpression of a rabbit carboxylesterase to sensitize neuroblastoma cells to CPT-11 - Pawlik_2000_Mol.Ther_1_457 |
| Author(s) : Pawlik CA , Iyengar RV , Krull EJ , Mason SE , Khanna R , Harris LC , Potter PM , Danks MK , Guichard SM |
| Ref : Mol Ther , 1 :457 , 2000 |
| Abstract : Overexpression of specific transcription factors by tumor cells can be exploited to regulate expression of proteins that induce apoptosis or activate prodrugs, thereby producing tumor-selective toxicity. A majority of advanced-stage neuroblastomas overexpress the transcription factor N-MYC, and this overexpression is associated with poor prognosis. This study describes regulation of expression by N-MYC, via the ornithine decarboxylase (ODC) promoter, of a rabbit liver carboxylesterase (CE) that activates the prodrug CPT-11. Chloramphenicol acetyltransferase reporter assays and CE activity assays in transiently transfected neuroblastoma cell lines (SJNB-1, SJNB-4, NB-1691) and rhabdomyosarcoma cell lines (JR1neo20, JR1Nmyc6, JR1Nmyc9) support this approach as a potential method for sensitizing tumor cells to CPT-11. Clonogenic assays with IMR32 human neuroblastoma cells which express N-MYC and that had been stably transfected with a plasmid containing an ODC promoter/CE cassette corroborated results of enzyme activity assays. Specifically, IMR32.ODC.CE cells expressed approximately eightfold more CE activity than IMR32.CMV.neo cells; and 5 microM CPT-11 reduced the clonogenic potential of IMR32.ODC.CE cells to zero, while 50 microM CPT-11 was required to produce the same effect with IMR32.CMV.neo cells. Current experiments focus on adenoviral delivery of an ODC promoter/CE cDNA cassette for potential virus-directed enzyme prodrug therapy applications. |
| ESTHER : Pawlik_2000_Mol.Ther_1_457 |
| PubMedSearch : Pawlik_2000_Mol.Ther_1_457 |
| PubMedID: 10933967 |
Pawlik CA, Iyengar RV, Krull EJ, Mason SE, Khanna R, Harris LC, Potter PM, Danks MK, Guichard SM (2000)
Use of the ornithine decarboxylase promoter to achieve N-MYC-mediated overexpression of a rabbit carboxylesterase to sensitize neuroblastoma cells to CPT-11
Mol Ther
1 :457
Pawlik CA, Iyengar RV, Krull EJ, Mason SE, Khanna R, Harris LC, Potter PM, Danks MK, Guichard SM (2000)
Mol Ther
1 :457