PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of bmccancBioMed Centralsearchsubmit a manuscriptregisterthis articleBMC Cancer
 
BMC Cancer. 2012; 12: 130.
Published online Mar 30, 2012. doi:  10.1186/1471-2407-12-130
PMCID: PMC3376035
JS-K, a glutathione/glutathione S-transferase-activated nitric oxide releasing prodrug inhibits androgen receptor and WNT-signaling in prostate cancer cells
Martin Laschak,1 Klaus-Dieter Spindler,1 Andres J Schrader,2 Andrea Hessenauer,1 Wolfgang Streicher,1,2 Mark Schrader,2 and Marcus V Cronauercorresponding author2
1Institute for General Zoology and Endocrinology, Ulm University, Albert Einstein Allee 23, 89069 Ulm, Germany
2Department of Urology, Ulm University, Prittwitzstrasse 43, 89075, Ulm, Germany
corresponding authorCorresponding author.
Martin Laschak: martin.laschak/at/uni-ulm.de; Klaus-Dieter Spindler: kmspindler/at/t-online.de; Andres J Schrader: ajschrader/at/gmx.de; Andrea Hessenauer: andrea.hessenauer/at/web.de; Wolfgang Streicher: wolfgang.streicher/at/uni-ulm.de; Mark Schrader: mark.schrader/at/uniklinik-ulm.de; Marcus V Cronauer: marcus.cronauer/at/uni-ulm.de
Received November 4, 2011; Accepted March 30, 2012.
Abstract
Background
Nitric oxide (NO) and its oxidative reaction products have been repeatedly shown to block steroid receptor function via nitrosation of zinc finger structures in the DNA-binding domain (DBD). In consequence NO-donors could be of special interest for the treatment of deregulated androgen receptor(AR)-signaling in castration resistant prostate cancer (CRPC).
Methods
Prostate cancer (PCa) cells were treated with JS-K, a diazeniumdiolate derivate capable of generating large amounts of intracellular NO following activation by glutathione S-transferase. Generation of NO was determined indirectly by the detection of nitrate in tissue culture medium or by immunodetection of nitrotyrosine in the cytoplasm. Effects of JS-K on intracellular AR-levels were determined by western blotting. AR-dimerization was analyzed by mammalian two hybrid assay, nuclear translocation of the AR was visualized in PCa cells transfected with a green fluorescent AR-Eos fusion protein using fluorescence microscopy. Modulation of AR- and WNT-signalling by JS-K was investigated using reporter gene assays. Tumor cell proliferation following JS-K treatment was measured by MTT-Assay.
Results
The NO-releasing compound JS-K was shown to inhibit AR-mediated reporter gene activity in 22Rv1 CRPC cells. Inhibition of AR signaling was neither due to an inhibition of nuclear import nor to a reduction in AR-dimerization. In contrast to previously tested NO-donors, JS-K was able to reduce the intracellular concentration of functional AR. This could be attributed to the generation of extremely high intracellular levels of the free radical NO as demonstrated indirectly by high levels of nitrotyrosine in JS-K treated cells. Moreover, JS-K diminished WNT-signaling in AR-positive 22Rv1 cells. In line with these observations, castration resistant 22Rv1 cells were found to be more susceptible to the growth inhibitory effects of JS-K than the androgen dependent LNCaP which do not exhibit an active WNT-signaling pathway.
Conclusions
Our results suggest that small molecules able to inhibit WNT- and AR-signaling via NO-release represent a promising platform for the development of new compounds for the treatment of CRPC.
Articles from BMC Cancer are provided here courtesy of
BioMed Central