A yeast-based functional assay for the detection of the mutant androgen receptor in prostate cancer.
OBJECTIVE
Mutations in the ligand-binding domain of the human androgen receptor (AR) figure among the ways used by prostate adenocarcinoma (PCa) cells to escape androgen dependence. These mutations may broaden the specificity and/or affinity of the AR to other hormones, resulting in inappropriate receptor activation and thus affecting the PCa response to physiological stimuli and hormonal therapies.


METHODS
In order to clarify the impact of these mutations on disease progression and treatment, we have developed a yeast-based functional assay that allows the detection of mutant ARs and the analysis of their transactivation capacities in response to different ligands.


METHODS
AR cDNA was directly cloned into an expression vector in a yeast strain that carries a reporter gene (ADE2) linked to an androgen-dependent promoter. The expression of the ADE2 gene and consequently the yeast cell growth in a selective medium depleted in adenine depends on the specificity of the AR for the ligand added to the medium.


RESULTS
By analysing the transactivation capacities of different AR molecules in response to a broad range of steroid and non-steroid ligands, we have demonstrated that this assay can discriminate among wild-type AR, T877A, C685Y and L701H mutant ARs and that at least 1% of mutant ARs could be detected when mutant and wild-type ARs were mixed at the cDNA level.


CONCLUSIONS
The data presented here show that this simple AR assay is convenient for the routine detection of mutant ARs in PCa and is also suitable to evaluate the antagonist activities of anti-androgen molecules.
Céraline
Jocelyn
J
Laboratoire de Cancerologie Experimentale et de Radiobiologie, EA 3430-ULP, IRCAD, 1, Place de l'Hopital, BP426, F67091 Strasbourg, France. jocelyn.ceraline@ircad.u-strasbg.fr
Erdmann
Eva
E
Erbs
Philippe
P
Deslandres-Cruchant
Marion
M
Jacqmin
Didier
D
Duclos
Brigitte
B
Klein-Soyer
Claudine
C
Dufour
Patrick
P
Bergerat
Jean-Pierre
JP
D000230:Adenocarcinoma; D000726:Androgen Antagonists / Q000378:metabolism / Q000494:pharmacology; D002262:Carboxy-Lyases / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008024:Ligands; D008297:Male; D016296:Mutagenesis; D011471:Prostatic Neoplasms; D011944:Receptors, Androgen / Q000235:genetics* / Q000378:metabolism; D012680:Sensitivity and Specificity; D014407:Tumor Cells, Cultured; D015003:Yeasts / Q000235:genetics*
D000726:Androgen Antagonists; D008024:Ligands; D011944:Receptors, Androgen; D002262:Carboxy-Lyases; C022378:phosphoribosylaminoimidazole carboxylase