PMID- 15526106
OWN - NLM
STAT- MEDLINE
DCOM- 20050524
LR  - 20181113
IS  - 0028-1298 (Print)
IS  - 0028-1298 (Linking)
VI  - 370
IP  - 5
DP  - 2004 Nov
TI  - Involvement of AP-2 binding sites in regulation of human beta-glucuronidase.
PG  - 331-9
AB  - The lysosomal hydrolase beta-glucuronidase (beta-gluc) can be used for the 
      bioactivation of non-toxic glucuronide prodrugs of anticancer agents. The enzyme 
      is present at high levels in many tumours and hence may lead to an enhanced drug 
      targeting by tumour-selective release of the active anticancer drug. Individual 
      expression and regulation of this enzyme is one factor modulating the 
      bioactivation of glucuronide prodrugs. Nevertheless, in contrast to murine 
      beta-gluc, which is inducible by androgens, the human enzyme has been regarded as 
      an unregulated housekeeping gene due to a lacking TATA box and high G+C contents 
      within the putative promotor sequence. Despite these facts, we were able to 
      demonstrate downregulation of human beta-gluc expression by the calcium ionophore 
      A23187 and the calcium ATPase inhibitor thapsigargin in the human hepatoma cell 
      line HepG2. However, cis-acting elements responsible for this regulation have not 
      yet been identified. We therefore characterised the 5'-untranslated region of the 
      human beta-gluc gene using transient transfection assays with promotor-luciferase 
      constructs in HepG2 cells and cloned fragments between 3,770 bp and 107 bp. 
      A23187 reduced the beta-gluc promotor activity. This effect disappeared using 
      fragments smaller than 356 bp. Using site-directed in vitro mutagenesis and 
      gel-electrophoretic-mobility shift assays, we found evidence of an involvement of 
      transcription factor activating protein-2 (AP-2) binding sites on the regulation 
      of human beta-glucuronidase by A23187. Our studies provide a basis for the 
      understanding of the transcriptional regulation of the human beta-glucuronidase 
      gene and could be useful for the optimisation of glucuronide prodrug therapy.
FAU - Kunert-Keil, Christiane
AU  - Kunert-Keil C
AD  - Department of Pharmacology and Peter Holtz Research Center of Pharmacology and 
      Experimental Therapeutics, Ernst Moritz Arndt-University, 
      Friedrich-Loeffler-Strasse 23d, 17487 Greifswald, Germany.
FAU - Sperker, Bernhard
AU  - Sperker B
FAU - Bien, Sandra
AU  - Bien S
FAU - Wolf, Gabriele
AU  - Wolf G
FAU - Grube, Markus
AU  - Grube M
FAU - Kroemer, Heyo K
AU  - Kroemer HK
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20041028
PL  - Germany
TA  - Naunyn Schmiedebergs Arch Pharmacol
JT  - Naunyn-Schmiedeberg's archives of pharmacology
JID - 0326264
RN  - 0 (DNA-Binding Proteins)
RN  - 0 (Transcription Factor AP-2)
RN  - 0 (Transcription Factors)
RN  - EC 3.2.1.31 (Glucuronidase)
SB  - IM
MH  - Binding Sites/physiology
MH  - Cell Line, Tumor
MH  - DNA-Binding Proteins/genetics/*metabolism/physiology
MH  - Glucuronidase/genetics/*metabolism
MH  - Humans
MH  - Protein Binding/physiology
MH  - Transcription Factor AP-2
MH  - Transcription Factors/genetics/*metabolism/physiology
EDAT- 2004/11/05 09:00
MHDA- 2005/05/25 09:00
CRDT- 2004/11/05 09:00
PHST- 2004/05/14 00:00 [received]
PHST- 2004/09/13 00:00 [accepted]
PHST- 2004/11/05 09:00 [pubmed]
PHST- 2005/05/25 09:00 [medline]
PHST- 2004/11/05 09:00 [entrez]
AID - 10.1007/s00210-004-0989-3 [doi]
PST - ppublish
SO  - Naunyn Schmiedebergs Arch Pharmacol. 2004 Nov;370(5):331-9. doi: 
      10.1007/s00210-004-0989-3. Epub 2004 Oct 28.