Prostate cancer treatment and the relationship of androgen deprivation therapy to cognitive function.

Prostate cancer is the second most common form of cancer in men. For advanced, high risk prostate cancer, androgen deprivation therapy (ADT) is the preferred treatment and can induce remission, but resistance to ADT brings biochemical recurrence and progression of cancer. ADT brings adverse effects such as erectile dysfunction, decreased libido, and diminished physical strength. It is estimated that between 25 and 50% of men on ADT manifest some form of cognitive dysfunction that may be self-reported or reported by a family member. There is concern that impaired cognitive function with ADT is due to loss of testosterone support. Testosterone and its metabolites are known to possess neuroprotective properties. While a direct causal relationship between ADT and cognitive decline in prostate cancer patients has not been established, this review describes the controversy surrounding the possible connection between ADT and neurocognitive deterioration. The cellular and molecular mechanisms believed to underlie the protection of neuronal integrity by androgens are discussed. Results from animal models and human clinical studies are presented. Finally, we call attention to lifestyle modifications that may minimize cognitive issues in prostate cancer patients.

Effect of inhibition of interleukin-12/23 by ustekinumab on the expression of leptin and leptin receptor in human THP-1 macrophages.

BACKGROUND: Leptin, an adipocyte-derived circulating cytokine that signals nutritional status, may play a role in the development of psoriasis and its associated systemic diseases. Patients with psoriasis have significantly decreased serum leptin levels compared with controls. AIM: To investigate the effect of two commonly used anti-psoriatic biologic drugs, adalimumab and ustekinumab, on leptin and leptin receptor expression in human macrophages. METHODS: THP-1 differentiated macrophages were cultured under the following conditions: (i) untreated control, (ii) adalimumab 5 µg/mL, (iii) ustekinumab 1 µg/mL and (iv) ustekinumab 5 µg/mL. Expression of leptin and leptin receptors were measured using real-time quantitative PCR and immunoblotting techniques. RESULTS: The presence of either adalimumab or ustekinumab in growth medium significantly upregulated expression of leptin receptor in THP-1 human macrophages to 1.98 ± 0.47 and 2.09 ± 0.24, respectively (n = 3, P < 0.01) vs. 1.12 ± 0.19 for untreated control cells. However, only ustekinumab at a concentration of 5 µg/mL augmented expression of leptin to 1.99 ± 0.56 (n = 3, P < 0.01) vs. control untreated cells. CONCLUSIONS: Enhanced leptin and leptin receptor expression in macrophages exposed to therapeutic levels of ustekinumab suggest a novel immunomodulatory mechanism for this biologic drug. Further mechanistic studies may yield targeted treatment using the leptin pathway, which could reduce the common obesity-related complications of psoriasis while alleviating symptoms and improving prognosis.

Plasma IL-33 in atopic patients correlates with pro-inflammatory cytokines and changes cholesterol transport protein expression: a surprising neutral overall impact on atherogenicity.

OBJECTIVE: Interleukin (IL)-33 has been associated with atopic and inflammatory conditions. IL-33 may be atheroprotective inducing a Th1-to-Th2 immunologic switch. However, the role of IL-33 in cardiovascular disease remains unclear. This study examines the effect of physiological and elevated IL-33 levels in plasma from atopic patients (AP) on cholesterol metabolism in human macrophages as compared to plasma from healthy controls (HC). METHODS: Twenty-five AP and 25 HC were enrolled in this study. Plasma samples were analysed for levels of IL-33, IFN-γ, TNF-α, IL-17α, IL-5 and soluble ST2. THP-1 differentiated macrophages were exposed to HC and AP plasma. Expression of proteins involved in reverse cholesterol transport (ABCA1, ABCG1 and 27-hydroxylase) and scavenger receptors, responsible for uptake of modified lipids (CD36, ScR-A1, CXCL16 and LOX-1), was measured using QRT-PCR and immunoblotting techniques. RESULTS: IL-33 was significantly higher in AP plasma: 106.7 ± 95 pg/mL versus HC plasma (53.4 ± 23 pg/mL). IL-33 concentration strongly correlated with levels of IFN-γ (r = 0.85), TNFα (r = 0.9) and IL-17α (r = 0.94). No significant difference was found in soluble ST2 levels. An important contrast was observed for 27-hydroxylase: normal IL-33 in AP plasma amplified 27-hydroxylase while increased IL-33 suppressed it. Expression of CD36 and SR-A1 was greater in macrophages exposed to plasma with high IL-33, while CXCL16 was higher in cells grown in the presence of plasma with normal IL-33. CONCLUSIONS: Here, we demonstrate that high levels of IL-33 and a high IL-33/soluble ST2 ratio correlates with elevated levels of IFN-γ, TNF-α and IL-17α as well as IL-5, demonstrating that IL-33 has pleiotropic effects. However, elevated IL-33 did not significantly impact lipid accumulation in macrophages overall. Given the wide variety of cellular responses regulated by IL-33, further investigation with a larger sample size will allow us to clarify the threshold concentration of IL-33 that leads to optimal cholesterol balance.

Oxysterol derivatives of cholesterol in neurodegenerative disorders.

Cholesterol is essential to the functions of the brain, which contains approximately 20% of the body's stores of this sterol. Most brain cholesterol is found in compacted myelin. The operation of the blood brain barrier (BBB) precludes the uptake of cholesterol from the periphery and consequently this sterol is produced de novo in the brain. In contrast, oxysterols - a class of hydroxylated cholesterol catabolites - traverse the BBB readily and facilitate the elimination of cholesterol from the brain. Oxysterols not only act as a transport form of cholesterol, but serve as endogenous regulators of gene expression in lipid metabolism and behave as ligands to nuclear receptors. Two of the more important brain-derived oxysterols are 24S-hydroxycholesterol and 27-hydroxycholesterol. Aberrant cholesterol metabolism has been implicated in a number of neurological disorders. Since oxysterols are thought to reflect the cerebral cholesterol turnover there has been great interest in the diagnostic and prognostic value of these metabolites in neurodegenerative diseases of the brain. The following article provides an overview of the involvement of oxysterols in Alzheimer's disease, multiple sclerosis and spastic paraplegias.

Adenosine A2A receptors in diffuse dermal fibrosis: pathogenic role in human dermal fibroblasts and in a murine model of scleroderma.

OBJECTIVE: Adenosine regulates inflammation and tissue repair, and adenosine A2A receptors promote wound healing by stimulating collagen matrix production. We therefore examined whether adenosine A2A receptors contribute to the pathogenesis of dermal fibrosis. METHODS: Collagen production by primary human dermal fibroblasts was analyzed by real-time polymerase chain reaction, 14C-proline incorporation, and Sircol assay. Intracellular signaling for dermal collagen production was investigated using inhibitors of MEK-1 and by demonstration of ERK phosphorylation. In vivo effects were studied in a bleomycin-induced dermal fibrosis model using adenosine A2A receptor-deficient wild-type littermate mice, C57BL/6 mice, and mice treated with adenosine A2A receptor antagonist. Morphometric features and levels of hydroxyproline were determined as measures of dermal fibrosis. RESULTS: Adenosine A2A receptor occupancy promoted collagen production by primary human dermal fibroblasts, which was blocked by adenosine A2A, but not A1 or A2B, receptor antagonism. Adenosine A2A receptor ligation stimulated ERK phosphorylation, and A2A receptor-mediated collagen production by dermal fibroblasts was blocked by MEK-1 inhibitors. Adenosine A2A receptor-deficient and A2A receptor antagonist-treated mice were protected from developing bleomycin-induced dermal fibrosis. CONCLUSION: These results demonstrate that adenosine A2A receptors play an active role in the pathogenesis of dermal fibrosis and suggest a novel therapeutic target in the treatment and prevention of dermal fibrosis in diseases such as scleroderma.

Immune complexes and IFN-gamma decrease cholesterol 27-hydroxylase in human arterial endothelium and macrophages.

The enzyme cholesterol 27-hydroxylase, expressed by arterial endothelium and monocytes/macrophages, is one of the first lines of defense against the development of atherosclerosis. By catalyzing the hydroxylation of cholesterol to 27-hydroxycholesterol, which is more soluble in aqueous medium, the enzyme promotes the removal of cholesterol from the arterial wall. Prior studies have suggested that immune reactants play a role in the pathogenesis of atherosclerosis; we report here that immune reactants, IFN-gamma and immune complexes bound to C1q, but not interleukin-1 and tumor necrosis factor, diminish the expression of cholesterol 27-hydroxylase in human aortic endothelial cells, peripheral blood mononuclear cells, monocyte-derived macrophages, and the human monocytoid cell line THP-1. In addition, our studies demonstrate that immune complexes down-regulate cholesterol 27-hydroxylase only after complement fixation via interaction with the 126-kD C1qRp protein on endothelial cells and THP-1 cells. These results are consistent with the prior demonstration that IFN-gamma contributes to the pathogenesis of atherosclerosis and suggest a role for C1q receptors in the atherogenic process. Moreover, these observations suggest that one mechanism by which immune reactants contribute to the development of atherosclerosis is by down-regulating the expression of the enzymes required to maintain cholesterol homeostasis in the arterial wall.

Inflammatory cytokines regulate function and expression of adenosine A(2A) receptors in human monocytic THP-1 cells.

Adenosine, acting at its receptors, particularly A(2A) receptors, is a potent endogenous anti-inflammatory agent that modulates the functions and differentiation of inflammatory and immune cells. Because the inflammatory milieu abounds in proinflammatory cytokines, we investigated the effects of Th1-inflammatory cytokines on function and expression of adenosine A(2A) receptors in the human monocytic cell line THP-1. We found that, consistent with previous reports, adenosine and 2-[p-(2-carnonylethyl)phenylethylamino]-5'-N-ethylcarboxamidoadenosine (CGS-21680), a selective A(2A) receptor agonist, suppress IL-12 production but increase IL-10 production in LPS-activated THP-1 cells. These effects were blocked by the A(2A) receptor antagonist 4-(2-[7-amino-2-(2-furyl)[1,2,4-triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol (ZM-241385). More importantly, the suppressive effect of adenosine and CGS-21680 on IL-12 production was significantly enhanced in cells pretreated with either IL-1 (10 U/ml) or TNF-alpha (100 U/ml) but markedly attenuated in cells pretreated with IFN-gamma (100 U/ml). Similarly, IL-1 and TNF-alpha treatment potentiated the stimulatory effect of adenosine and CGS-21680 on IL-10 production, whereas IFN-gamma treatment almost completely abolished this effect. CGS-21680 stimulated an increase in intracellular cAMP in a time- and dose-dependent manner in IL-1- and TNF-alpha-treated cells but not in control or IFN-gamma-treated cells. Both IL-1 and TNF-alpha increased A(2A) receptor mRNA and protein. In parallel with its effect on A(2A) receptor function, IFN-gamma down-regulated A(2A) receptor message and protein. Because adenosine mediates many of the antiinflammatory effects of drugs such as methotrexate, these observations suggest that local changes in the cytokine milieu may influence the therapeutic response to those drugs by altering the expression and function of adenosine receptors on inflammatory cells.

Sterol 27-hydroxylase: expression in human arterial endothelium.

Human endothelium obtained from both the aorta and the pulmonary artery has been evaluated for the presence of the messenger RNA coding for the expression of sterol 27-hydroxylase. Unique oligomers were designed to detect the mRNA by reverse transcription followed by the polymerase chain reaction. The amplified product was sequenced and was found to be identical to the published sequence for nucleotides 491 to 802 of the human sterol 27-hydroxylase cDNA. Northern blot analysis confirmed the presence of 27-hydroxylase mRNA in pulmonary artery and aortic endothelium. As part of these studies, enzymatic activity was assayed in cultured arterial endothelium using cholesterol as a substrate and isotope ratio gas-liquid chromatography-mass spectrometry to identify the metabolites, 27-hydroxycholesterol and 3 beta-hydroxy-5-cholestenoic acid, in the medium. Localization of sterol 27-hydroxylase to vascular endothelium indicates intracellular production of the biologically active metabolite 27-hydroxycholesterol.

7 alpha-hydroxylation of 27-hydroxycholesterol: biologic role in the regulation of cholesterol synthesis.

The report of a novel cytochrome P450 enzyme in mouse hippocampus (cyp7b) with close homology to cholesterol 7 alpha-hydroxylase led us to determine the substrate specificity with respect to 27-hydroxycholesterol, known to be a potent inhibitor of cholesterol synthesis. Transfection of 293/T-cells with PcDNA3.1(+)-mcyp7b was followed by metabolism of 2.5 microM 27-hydroxycholesterol to the 7 alpha-hydroxy intermediate, cholest-5-ene,3 beta,7 alpha,27-triol, with complete loss of down-regulation of cholesterol synthesis. Addition of 5 microM and 10 microM concentrations of the triol to HepG2 and CHO cells, respectively, also did not reduce cholesterol synthesis. The contrast between the biologic effect on cholesterol synthesis by these two C27 hydroxysterols and the wide tissue distribution of both cholesterol 27-hydroxylase and hydroxysterol 7 alpha-hydroxylase implies local regulatory effects prior to their further catabolism in the liver to chenodeoxycholic and cholic acids.

Sterol 27-hydroxylase: high levels of activity in vascular endothelium.

Sterol 27-hydroxylase activity in bovine aortic endothelial (BAE) cells in culture has been compared with that in HepG2 cells and in Chinese hamster ovary (CHO) cells using identical culture conditions. The total enzyme activity of BAE cells (3.0 nmol/72 h per mg cell protein) was comparable with that of HepG2 cells (4.0 nmol/72 h per mg protein) and both values were significantly greater than that in CHO cells (0.002 nmol/72 h per mg protein). The enzyme was identified in the mitochondria extracted from BAE cells by Western blotting using an antibody of proven specificity, and its metabolites 27-hydroxycholesterol and 3 beta-hydroxy-5-cholestenoic acid were identified by mass spectrum analysis. The presence of the enzyme in endothelium provides a mechanism for preventing accumulation of intracellular cholesterol by initiating a pathway of bile acid synthesis different from that initiated by 7 alpha-hydroxylation of cholesterol in the liver.