Use of the human MDR1 promoter for heat-inducible expression of therapeutic genes

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Item Type:	Article
Title:	Use of the human MDR1 promoter for heat-inducible expression of therapeutic genes
Creators Name:	Walther, W., Stein, U. and Schlag, P.M.
Abstract:	The promoter of the human multidrug resistance gene (mdr1) harbors stress-responsive elements, which can be induced e.g., by heat or cytostatic drugs. In previous studies the drug-responsiveness of the mdr1 promoter was successfully used for the drug-inducible expression of the human TNF-{alpha} gene in vitro and in vivo. Beside the drug-responsive elements of the mdr1 promoter, heat-shock responsive elements have also been identified, which could be exploited for construction of heat-inducible expression vectors. To analyze the hyperthermia-inducibility of the mdr1 promoter we used the pmdr-p-CAT and pM3mdr-p-hTNF vector constructs. Both constructs carry the mdr1 promoter fragment spanning from - 207 to + 153 to drive expression of the CAT-reporter or TNF-{alpha} gene. We tested the heat-induced CAT-reporter and TNF-{alpha} expression in vitro in transduced HCT15 and HCT116 human colon carcinoma cells. For the studies the transduced tumor cells were treated with hyperthermia at 41.5°C or 43°C for 2 hr to induce CAT or TNF-α expression. Cells and supernatants were harvested before hyperthermia and at certain time points (0-120 hr) after heat shock. The heatinduced CAT-reporter expression or TNF-{alpha} secretion was determined by specific ELISA. The experiments indicate that hyperthermia activates the mdr1 promoter in a temperature and time dependent manner. This induction leads to an 2- to 4-fold increase in CAT-reporter or 2- to 7-fold increase in TNF{alpha} expression in the tumor cell lines. These experiments reveal that the mdr1 promoter driven expression of therapeutic genes can be employed for combined cancer gene therapy approaches.
Keywords:	Cancer, Gene Therapy, Hyperthermia, Mdr1 Promoter
Source:	International Journal of Cancer
ISSN:	0020-7136
Publisher:	Wiley
Volume:	98
Number:	2
Page Range:	291-296
Date:	1 January 2002
PubMed:	View item in PubMed

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