Activation of the CMV-IE Promoter by Hyperthermia In Vitro and In Vivo: Biphasic Heat Induction of Cytosine Deaminase Suicide Gene Expression

作者：Kobelt Dennis; Aumann Jutta; Fichtner Iduna; Stein Ulrike; Schlag Peter M; Walther Wolfgang^*

来源：Molecular Biotechnology, 2010, 46(2): 197-205.

DOI：10.1007/s12033-010-9292-3

• CMV-promoter
• Hyperthermia
• Heat induction
• Gene therapy
• Cancer
• Cytosine deaminase
• Transcription factor

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 42A degrees C. The SW480/CMVCD cells were also used for in vivo studies, in which tumor-bearing animals were treated with hyperthermia at 41.5A 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.

• 出版日期2010-10