Functional testosterone receptors in plasma membranes of T cells

Abstract

T cells are considered to be unresponsive to testosterone due to the absence of androgen receptors (AR). Here, we demonstrate the testosterone responsiveness of murine splenic T cells in vitro as well as the presence of unconventional cell surface receptors for testosterone and classical intracellular AR. Binding sites for testosterone on the surface of both CD4(+) and CD8(+) subsets of T cells are directly revealed with the impeded ligand testosterone-BSA-FITC by confocal laser scanning microscopy (CLSM) and flow cytometry, respectively. Binding of the plasma membrane impermeable testosterone-BSA conjugate induces a rapid rise (<5 s) in [Ca2+]i of Fura-2-loaded T cells. This rise reflects influx of extracellular Ca2+ through non-voltage-gated and Ni2+-blockable Ca2+ channels of the plasma membrane. The testosterone-BSA-induced Ca2+ import is not affected by cyproterone, a blocker of the AR. In addition, AR are not detectable on the surface of intact T cells when using anti-AR antibodies directed against the amino and carboxy terminus of the AR, although T cells contain AR, as revealed by reverse transcription-polymerase chain reactions and Western blotting. AR can be visualized with the anti-AR antibodies in the cytoplasm of permeabilized T cells by using CLSM, though AR are not detectable in cytosol fractions when using the charcoal binding assay with 3H-R1881 as ligand. Cytoplasmic AR do not translocate to the nucleus of T cells in the presence of testosterone, in contrast to cytoplasmic AR in human cancer LNCaP cells. These findings suggest that the classical AR present in splenic T cells are not active in the genomic pathway. By contrast, the cell surface receptors for testosterone are in a functionally active state, enabling T cells a nongenomic response to testosterone.

Androgens alter T-cell immunity by inhibiting T-helper 1 differentiation

“…Various studies have demonstrated the presence of AR both in the cytosol and on the membrane of T lymphocytes (26,27). We found that there was an AR binding site in the intron between exon 3 and 4 of the Ptpn1 gene.…”

Combining a Recombinant Cancer Vaccine with Standard Definitive Radiotherapy in Patients with Localized Prostate Cancer

“…Androgens have been reported to inhibit cellular immunity, immunoglobulin synthesis, and production of cytokines. This action is explained by the existence of androgen receptors in T cells (45 (46 -48). Although there were no substantial differences in the PSA-specific immune responses of the 3 of 17 patients who were not treated with ADT compared with those who were, there are too few patients to answer this question with any certainty.…”

Membrane androgen receptor activation in prostate and breast tumor cells: Molecular signaling and clinical impact

“…Three classes of mAR ligands have been reported to date and include natural androgen steroids such as testosterone and DHT (8,9,19,22), albumin conjugated steroids (8,9,19,22) and the less well characterized class of flavonol compounds comprising catechin, epicatechin, and their oligomers (47). Although current clinical practice precludes use of testosterone for the treatment of prostate tumors because of its tumor promoting action via the iAR pathway, albumin conjugated androgens are reasonably expected to initiate only mAR-dependent effects in cells.…”

“…Non-genomic steroid actions have been reported for most steroids including glucocorticoids (1)(2)(3)(4), progesterone (5), estrogens (6,7), androgens (8,9), and neurosteroids (10). For a recent review, see (11).…”

“…Most recently, membrane androgen receptors transmitting rapid androgen signals have been characterized biochemically in several cell types including macrophages and T cells (8,19), LNCaP (9), T47D (15), MCF7 (20), DU145 (21), C6 (22), PC12 (23), or VSMC cells (24). Signals emanating from this receptor result in increased intracellular [Ca 21 ] and inositol 1,4,5-triphosphate formation, cannot be blocked by anti-androgens (9,25) and are sensitive to pertussis toxin inhibition indicating that mAR may actually be a GPCR (14)(15)(16).…”