ABSTRACT
The participation of aberrant receptors and intra-adrenal ACTH in hyperplastic tissue are considered mechanisms that regulate hypercortisolism in PMAH. Additionally, germline ARMC5 mutations have been described as the most frequent genetic abnormality found in patients diagnosed with PMAH. Previous functional studies analyzed ARMC5 role using H295R cells. Therefore, we investigated the role of ARMC5 in cell cultures obtained from PMAH nodules containing steroidogenic cells, aberrant receptors and intra-adrenal ACTH. ARMC5 silencing in non-mutated PMAH cell cultures decreased steroidogenesis-related genes and increased CCNE1 mRNA expression and proliferative capacity without affecting cell viability. Additionally, ARMC5 overexpression induced cell death in PMAH mutated cell cultures, thereby decreasing cell viability. We confirmed the role of ARMC5 as an important pro-apoptotic protein involved in PMAH-related steroidogenesis. We also report for the first time the involvement of ARMC5 in controlling proliferation and regulating cell cycle in PMAH cell cultures; these effects need to be explored further.
Subject(s)
Adrenal Glands/metabolism , Adrenal Glands/pathology , Tumor Suppressor Proteins/metabolism , Adrenocorticotropic Hormone/metabolism , Adrenocorticotropic Hormone/pharmacology , Aged , Armadillo Domain Proteins , Cells, Cultured , Female , Gene Expression Regulation/drug effects , Gene Silencing , Humans , Hyperplasia , Lipid Droplets/drug effects , Lipid Droplets/metabolism , Male , Middle Aged , Mutation/genetics , Pro-Opiomelanocortin/metabolism , Progesterone Reductase/genetics , Progesterone Reductase/metabolism , Receptor, Melanocortin, Type 2/metabolism , Receptors, G-Protein-Coupled/metabolism , Sequence Analysis, DNA , Staining and Labeling , Steroid 17-alpha-Hydroxylase/genetics , Steroid 17-alpha-Hydroxylase/metabolism , Tumor Suppressor Proteins/genetics , Vasopressins/pharmacologyABSTRACT
CONTEXT: Among the genomic loci harboring potential candidate genes for prostatic cancer (PCa) is the 2q31-33 chromosomal region that harbors the gene encoding phosphodiesterase 11A (PDE11A). In addition, the combined cancer genome expression metaanalysis datasets included PDE11A among the top 1% down-regulated genes in PCa. OBJECTIVE: In the present study, we screened 50 unrelated PCa patients of Brazilian descent for PDE11A coding defects. DESIGN: The study consisted of PDE11A sequencing, in vitro functional assays, and immunostaining analysis. RESULTS: We identified eight different sequence alterations in 15 patients (30%): one stop-codon and seven missense mutations. Three of the variants (R202C, Y658C, and E840K) were novel, and the remaining five (Y727C, R804H, R867G, M878V, and R307X) have been associated with predisposition to adrenal or testicular tumors. The overall prevalence of PDE11A-inactivating sequence variants among PCa patients was significantly higher than in 287 healthy controls (0.16 vs. 0.051, respectively, P < 0.001, odds ratio 3.81, 95% confidence interval 1.86-7.81) and the R202C, Y658C, and E840K substitutions were not found in controls. All missense mutations led to decreased PDE11A activity in human embryonic kidney 293 and PC3M cells and immunostaining of PCa samples with sequence changes showed decreased PDE11A protein expression. CONCLUSION: Our data suggest that, like in the adrenal cortex and the testicular germ cells, PDE11A-inactivating genetic alterations may play a role in susceptibility to PCa.