Disease relevance of CDB 904

• Using the mRNA differential display technique and Northern blot analysis, we have shown that chronic exposure of the prostate cancer epithelial cell line LNCaP to the synthetic androgen mibolerone results in the down-regulation of PPARalpha mRNA [1].
• Mibolerone-treated chicks were subsequently challenged with sheep red blood cells (SRBC) and Brucella abortus at 1, 7, 14, or 21 days of age [2].
• No indication was found that mibolerone prevented IBDV infection even after 7 weeks of feeding [3].
• Bitches were treated orally for 5 consecutive days with one of the following dosages of mibolerone: 0.008, 0.016, or 0.025 mg/kg of body weight [4].
• Canine ovarian fibroma associated with prolonged exposure to mibolerone [5].

High impact information on CDB 904

• In addition, polysome run-off translation assays demonstrated an increase in PCNA protein after a 6-h stimulation of LNCaP cells with 10(-9)M mibolerone [6].
• A time course study demonstrated that PSA mRNA was induced by mibolerone (a nonmetabolizable synthetic androgen) and reached maximal levels after 9 h [7].
• Following incubation with androgen (2 nM mibolerone) for 72 h, luciferase activity in normal fibroblasts increased > 10-fold (range 11-200-fold) in a manner that corresponded with the level of androgen receptor detected in ligand-binding assays [8].
• For this purpose, NIS mRNA and protein expression levels were examined in NP-1 cells by Northern and Western blot analysis, respectively, after incubation with Dex (10(-8)-10(-6) M) in the presence of 10(-9) M mibolerone [9].
• Binding studies with the mutant receptor in transfected COS-7 cells, with mibolerone as ligand, exhibited equal Kd (0.7 vs. 1.0 nmol/ L), IC50 (0.8 vs. 1.1 nmol/L), and maximum binding (7.1 vs. 8.9 fmol/ 10(6) cells), as compared with the wild-type (WT) receptor [10].

Biological context of CDB 904

• However, androgen binding in fibroblast monolayers was thermolabile, up-regulation of receptor levels did not occur after prolonged incubation of monolayers with dihydrotestosterone or methyltrienolone, and dissociation rates at 37 C were increased with the synthetic androgen mibolerone [11].
• Mibolerone also caused a significant decrease in cell death in 2 out of 5 (40%) cultures tested [12].
• Delayed development of humoral immunity in chickens following in ovo treatment with mibolerone [2].
• After extraction of binding sites, microsomes are capable of accepting cytosol mibolerone-receptor complexes to a level similar to the concentration of depleted binding sites; microsomes from nontarget tissues do not manifest such capability [13].
• Despite the expression of AR RNA and protein, PC-3AR+ cell proliferation was unaffected by the presence of 0.1-10 nM mibolerone [14].

Anatomical context of CDB 904

• Cytosol binders precipitate upon 90% saturation with (NH4)SO4 and have higher affinity for DHT than mibolerone [15].
• For this purpose, NIS mRNA and protein expression levels in the NIS-transfected LNCaP cell line NP-1 were examined by Northern and Western blot analysis following incubation with atRA (10 (-9) to 10(-6) M) in the presence of 10(-9) M mibolerone (mib) [16].
• Preincubation of Sertoli cells for 4 days with FSH, testosterone, or 5 alpha-dihydrotestosterone results into a 2- to 3-fold increase in mibolerone binding, as measured 18 h after removal of the agonists [17].
• In rat uterus and prostate, 7 alpha, 17 alpha-dimethyl-19-nortestosterone (DMNT) binds to the androgen receptor specifically and with high affinity [18].
• These results indicate that mibolerone causes delayed rather than rapid development of the humoral immune system [2].

Associations of CDB 904 with other chemical compounds

• In COS-1 cells transfected with the E772A and R871G hARs, the apparent equilibrium dissociation constants (Kd) for mibolerone (MB) and methyltrienolone are normal [19].
• The influence of FSH and androgens on androgen receptor levels in primary Sertoli cell cultures from immature rats is studied in a monolayer binding assay and by sucrose density gradient centrifugation using the synthetic radiolabeled androgen mibolerone (7 alpha, 17 alpha-dimethyl-19-nortestosterone) as a ligand [17].
• Addition of 17beta-hydroxy-5alpha-androstan-3-one (DHT), 11-ketotestosterone (11-KT), or Mibolerone to ovarian incubations caused dose-dependent decreases in gonadotropin-stimulated in vitro estradiol production, which was not reversed by cotreatment with the antiandrogens, cyproterone acetate or 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene [20].
• Concomitant treatment with mibolerone (100 nM) decreased the synergistic action of insulin or IGF-I on hCG-stimulated androsterone synthesis by 46% and 40%, respectively [21].
• METHODS: LNCaP cells were grown in serum-free medium with 10 ng/ml or 100 ng/ml EGF, 0.1 nM or 1.0 nM mibolerone (a potent androgen agonist), or vehicle (distilled water or 0.01% ethanol) [22].

Gene context of CDB 904

• Time course analysis revealed that hGK-1 mRNA levels increased significantly at 5 h of mibolerone treatment and reached maximal levels by 9 h [23].
• There were no effects on cyclin D1 protein or mRNA expression with mibolerone treatments [22].
• Degradation rate of 35S-labeled AR was significantly increased by GA in the presence or absence of mibolerone [24].
• The induction of PSA mRNA required as little as 0.3 nM mibolerone [7].
• Surprisingly, mibolerone was found to bind with high affinity to the progesterone receptor in both human prostate (Kd = 5.9 nM) and rabbit uterus (Kd = 1.1 nM) [25].

Analytical, diagnostic and therapeutic context of CDB 904

• Using an expression vector in which the identified mutation was recreated by site-directed mutagenesis, the mutant receptor was found to have a reduced binding affinity (Kd = 3.06 nmol/L) for mibolerone compared with that of normal AR (Kd = 1.71 nmol/L) when expressed in COS-7 cells [26].
• Mibolerone (dimethylnortestosterone) or 5 alpha-dihydrostestosterone (DHT) increase intracellular calcium (Ca2+i) of human prostate cancer cells (LNCaP) as early as 2 min after treatment [27].
• A study to determine the efficacy and safety of mibolerone following prolonged oral administration in the female dog was terminated after 9.6 yr [5].
• The total concentration of plasma IgG, measured by radial immunodiffusion, was diminished whereas the IgM level was not influenced by the mibolerone treatment [28].
• Efficacy and dosage titration study of mibolerone for treatment of pseudopregnancy in the bitch [4].

References