Activation of the CMV-IE promoter by hyperthermia in vitro and in vivo: biphasic heat induction of cytosine deaminase suicide gene expression

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Item Type:	Article
Title:	Activation of the CMV-IE promoter by hyperthermia in vitro and in vivo: biphasic heat induction of cytosine deaminase suicide gene expression
Creators Name:	Kobelt, D., Aumann, J., Fichtner, I., Stein, U., Schlag, P.M. and Walther, W.
Abstract:	The cytomegalovirus-immediate early (CMV-IE) promoter is widely used as a strong and constitutively active promoter. Although the CMV-IE promoter does not harbor heat-responsive sequences, we determined its heat inducibility. We analyzed in vitro and in vivo heat responsiveness and possible mechanisms of heat induction of the CMV-IE promoter. We used transfected SW480 human colon carcinoma cells (SW480/CMVCD), expressing CMV-IE promoter-driven bacterial cytosine deaminase (CD) gene. These cells were heated at 42 degrees C. The SW480/CMVCD cells were also used for in vivo studies, in which tumor-bearing animals were treated with hyperthermia at 41.5 degrees C. As controls, SW480 (SW480/HSPCD) cells were used, in which CD expression is driven by the HSP70-promoter. In vitro, we observed a biphasic, up to 25-fold heat induction of CMV-IE-driven CD expression after hyperthermia in SW480/CMVCD cells. In vivo, we found a 2.5-fold induction of CD expression after hyperthermia in SW480/CMVCD tumor-bearing animals. The analysis of the CMV-IE promoter sequence revealed several transcription factor-binding sites, which mediate stress responsiveness. YB-1 and C/EBP-beta might mediate heat responsiveness of the CMV-IE promoter. These data point to limitations in heat-induction gene therapy studies, in which the CMV-IE promoter is used as control system. In addition, the CMV-IE promoter itself could well be used for construction of heat-inducible vectors.
Keywords:	CMV-Promoter, Hyperthermia, Heat Induction, Gene Therapy, Cancer, Cytosine Deaminase, Transcription Factor, Animals, Mice
Source:	Molecular Biotechnology
ISSN:	1073-6085
Publisher:	Humana Press
Volume:	46
Number:	2
Page Range:	197-205
Date:	October 2010
Official Publication:	https://doi.org/10.1007/s12033-010-9292-3
PubMed:	View item in PubMed

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