title: 4-Epidoxycycline: an alternative to doxycycline to control gene expression in conditional mouse models.
abstract: Since the pioneering work by Gossen and Bujard in 1992 demonstrating the usefulness of the Escherichia coli derived tet resistance operon for regulating gene expression a large collection of doxycycline-controlled transgenic mice has been established. Gene switching in eukaryotic tissue culture cells or mice requires administration of tetracycline, anhydrotetracycline or doxycycline to efficiently inactivate the transactivator protein tTA (TET-OFF system) or alternatively to activate the reverse transactivator protein rtTA (TET-ON system). However, the antibiotic activity of doxycycline can create an imbalance of the intestinal flora, resulting in diarrhoea and in a smaller number of animals in colitis. Previous studies reported that 4-epidoxycycline (4-ED), a hepatic metabolite of doxycycline, does not function as an antibiotic in mice. This gave us the idea that 4-ED might be useful for controlling gene expression in mice without the unwanted antibiotic side effect. To study the applicability of 4-ED for control of gene expression we used cell lines expressing the oncogene HER2 under control of tTA (TET-OFF) as well as rtTA (TET-ON). 4-ED and doxycycline were similarly efficient in switching on or -off HER2 expression. In vivo we used a conditional mouse model that allows switching off HER2 in tumor tissue. We show that (i) doxycycline, 7.5mg/ml in drinking water (used as a positive control), (ii) 4-ED, 7.5mg/ml in drinking water, (iii) 4-ED, 10mg/kg body weight, s.c., and (iv) anhydrotetracycline, 10mg/kg, s.c. (used as a second positive control), were similarly efficient. Using mice with tumor volumes of 1.6cm(3) all four schedules led to a tumor remission of more than 95% within 7 days. In conclusion, 4-ED is similarly efficient as doxycycline to control gene expression in vitro and in mice. Since 4-ED lacks the antibiotic activity of doxycycline it may help to avoid adverse side effects and selection of resistant bacteria.
authors.affiliation: Institute of Pharmacy, University of Leipzig, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Eger
authors.forename: M
authors.initials: M
authors.lastname: Hermes
authors.forename: K
authors.initials: K
authors.lastname: Uhlemann
authors.forename: S
authors.initials: S
authors.lastname: Rodewald
authors.forename: J
authors.initials: J
authors.lastname: Ortwein
authors.forename: M
authors.initials: M
authors.lastname: Brulport
authors.forename: A W
authors.initials: AW
authors.lastname: Bauer
authors.forename: W
authors.initials: W
authors.lastname: Schormann
authors.forename: F
authors.initials: F
authors.lastname: Lupatsch
authors.forename: I B
authors.initials: IB
authors.lastname: Schiffer
authors.forename: C K
authors.initials: CK
authors.lastname: Heimerdinger
authors.forename: S
authors.initials: S
authors.lastname: Gebhard
authors.forename: C
authors.initials: C
authors.lastname: Spangenberg
authors.forename: D
authors.initials: D
authors.lastname: Prawitt
authors.forename: T
authors.initials: T
authors.lastname: Trost
authors.forename: B
authors.initials: B
authors.lastname: Zabel
authors.forename: C
authors.initials: C
authors.lastname: Sauer
authors.forename: B
authors.initials: B
authors.lastname: Tanner
authors.forename: H
authors.initials: H
authors.lastname: Kolbl
authors.forename: U
authors.initials: U
authors.lastname: Krugel
authors.forename: H
authors.initials: H
authors.lastname: Franke
authors.forename: P
authors.initials: P
authors.lastname: Illes
authors.forename: P
authors.initials: P
authors.lastname: Madaj-Sterba
authors.forename: E O
authors.initials: EO
authors.lastname: Bockamp
authors.forename: T
authors.initials: T
authors.lastname: Beckers
authors.forename: J G
authors.initials: JG
authors.lastname: Hengstler
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism*; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004318:Doxycycline / Q000008:administration & dosage*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008822:Mice, Transgenic; D041681:NIH 3T3 Cells; D051381:Rats; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D013237:Stereoisomerism; D013754:Tetracyclines / Q000008:administration & dosage; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D004318:Doxycycline; D018719:Erb-b2 Receptor Tyrosine Kinases; D013754:Tetracyclines; C016229:4-epianhydrotetracycline