metribolone and Liver-Neoplasms

Hepatocellular carcinoma (HCC) is one of the most fatal cancers. In almost all populations, males have a higher HCC rate than females. Here we sought to explore the roles and mechanisms of acetylcholine (Ach) and androgen receptor (AR) on regulating the fate determinations of HCC. Ach activated AR and promoted its expression in HCC cells. Ach enhanced HCC cell migration and invasion but inhibited their apoptosis. Ach had no obvious effects on the migration, invasion, or apoptosis in AR-negative HCC cells. Elevation of migration and invasion induced by Ach was eliminated in AR-knockdown HCC cells. In contrast, Ach stimulated the migration and invasion but suppressed apoptosis in AR over-expressed HCC cells. Additionally, AR agonist R1881 promoted the migration and invasion but reduced the apoptosis of SNU-449 cells, whereas AR antagonist casodex inhibited the migration and invasion but stimulated the apoptosis of SNU-449 cells. STAT3 and AKT phosphorylation was activated by Ach in HCC cells. Collectively, these data suggest that Ach activates STAT3 and AKT pathways and acts on AR to promote the migration and invasion but inhibit the apoptosis of HCC cells. This study thus provides novel insights into carcinogenesis of liver cancer by local interaction between neurotransmitter Ach and hormone receptor AR in HCC.

Topics: Acetylcholine; Androgen Antagonists; Androgens; Anilides; Apoptosis; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Movement; Female; Gene Expression Regulation, Neoplastic; Humans; Liver Neoplasms; Male; Mecamylamine; Metribolone; Neoplasm Invasiveness; Nitriles; Phosphorylation; Proto-Oncogene Proteins c-akt; Receptors, Androgen; Receptors, Cholinergic; RNA, Small Interfering; Signal Transduction; STAT3 Transcription Factor; Tosyl Compounds; Transcription, Genetic; Up-Regulation

The androgen receptor (AR) is essential for development of the male gender and in the growth of the majority of prostate cancers. Agonists as well as most antagonists induce translocation of the receptor to the nucleus, whereas only agonists can activate AR function. Antagonists are therefore used in the therapy of metastasized prostate cancer. To obtain insight into the mechanism by which antagonists block AR function in living cells, we studied nuclear mobility and localization of green fluorescent protein (GFP)-tagged AR in the presence of either the agonist R1881 or the antagonists bicalutamide and hydroxyflutamide. As controls we investigated a non-DNA-binding AR mutant (A573D) and two mutants (W741C and T877A) with broadened ligand specificity. We demonstrate that in the presence of R1881, AR localizes in numerous intranuclear foci and, using complementary fluorescence recovery after photobleaching (FRAP) approaches and computer modelling, that a fraction of AR ( approximately 10-15%) is transiently immobilized in a DNA-binding-dependent manner (individual ARs being immobile for approximately 45 seconds). By contrast, antagonist-bound GFP-AR showed no detectable immobile fraction and the mobility was similar to that of the R1881-liganded non-DNA-binding mutant (A573D), indicating that antagonists do not induce the relatively stable DNA-binding-dependent immobilization observed with agonist-bound AR. Moreover, in the presence of bicalutamide and hydroxyflutamide GFP-AR was homogeneously distributed in the nucleus. Binding of bicalutamide and hydroxyflutamide to GFP-AR(W741C) and GFP-AR(T877A), respectively, resulted in similar mobility and heterogeneous nuclear distribution as observed for R1881-liganded GFP-AR. The live cell studies indicate that the investigated antagonists interfere with events early in the transactivation function of the AR.

Topics: Androgen Antagonists; Androgen Receptor Antagonists; Androgens; Anilides; Blotting, Western; Carcinoma, Hepatocellular; Cell Line, Tumor; Cells, Cultured; Computer Simulation; DNA; DNA-Binding Proteins; DNA, Neoplasm; Flutamide; Green Fluorescent Proteins; Humans; Liver Neoplasms; Male; Metribolone; Nitriles; Prostatic Neoplasms; Receptors, Androgen; Recombinant Fusion Proteins; Tosyl Compounds

Liver is responsive to sex hormones. The role of androgens in normal human liver function is not well understood, although androgens have been implicated in several liver diseases. Because the human hepatic androgen receptor has not been adequately characterized, we analyzed cytosolic and nuclear fractions from normal human liver of both sexes for androgen-binding activity using multipoint saturation analysis with the androgenic radioligand methyltrienelone (R1881). Both cytosolic and nuclear fractions of both sexes displayed high affinity R1881 binding (dissociation constants = nanomolar range). The R1881 binding in both fractions is highly specific in that potent androgens compete well, and the antiandrogens hydroxyflutamide and cyproterone acetate show partial competition; other nonandrogenic steroid hormones do not compete. The cytosolic R1881 receptor displays physicochemical characteristics of androgen receptors in other tissues in that it is retained by heparin-Sepharose and by DNA cellulose after activation, and it displays a molybdate-stabilized 8S form on sucrose gradients and a 7.3-nm species on gel filtration chromatography. Receptor activity was also quantitated in specimens of hepatic adenoma, focal nodular hyperplasia and metastatic carcinoma to the liver and in samples of adjacent histologically normal specimens when available. In general, both the diseased and normal portions of the livers from the patients with hepatic adenoma and metastatic carcinoma to the liver, but not focal nodular hyperplasia, demonstrated reduced total androgen-receptor activity as compared with liver from normal individuals.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Androgen Antagonists; Androgens; Binding, Competitive; Cell Nucleus; Cytosol; Female; Humans; Hyperplasia; Liver; Liver Diseases; Liver Neoplasms; Male; Metribolone; Middle Aged; Receptors, Androgen