Androgen receptor levels are increased by interferons in human prostate stromal and epithelial cells

Novel genes and sex differences in COVID-19 severity

Here we describe the results of a genome-wide study conducted in 11 939 COVID-19 positive cases with an extensive clinical information that were recruited from 34 hospitals across Spain (SCOURGE consortium). In sex-disaggregated genome-wide association studies for COVID-19 hospitalization, genome-wide significance (p < 5x10-8) was crossed for variants in 3p21.31 and 21q22.11 loci only among males (p = 1.3x10-22 and p = 8.1x10-12, respectively), and for variants in 9q21.32 near TLE1 only among females (p = 4.4x10-8). In a second phase, results were combined with an independent Spanish cohort (1598 COVID-19 cases and 1068 population controls), revealing in the overall analysis two novel risk loci in 9p13.3 and 19q13.12, with fine-mapping prioritized variants functionally associated with AQP3 (p = 2.7x10-8) and ARHGAP33 (p = 1.3x10-8), respectively. The meta-analysis of both phases with four European studies stratified by sex from the Host Genetics Initiative confirmed the association of the 3p21.31 and 21q22.11 loci predominantly in males and replicated a recently reported variant in 11p13 (ELF5, p = 4.1x10-8). Six of the COVID-19 HGI discovered loci were replicated and an HGI-based genetic risk score predicted the severity strata in SCOURGE. We also found more SNP-heritability and larger heritability differences by age (<60 or ≥ 60 years) among males than among females. Parallel genome-wide screening of inbreeding depression in SCOURGE also showed an effect of homozygosity in COVID-19 hospitalization and severity and this effect was stronger among older males. In summary, new candidate genes for COVID-19 severity and evidence supporting genetic disparities among sexes are provided.

Human Prostate Epithelial Cells Activate the AIM2 Inflammasome upon Cellular Senescence: Role of POP3 Protein in Aging-Related Prostatic Inflammation

Increased levels of type I (T1) interferon (IFN)-inducible POP3 protein in myeloid cells inhibit activation of the AIM2 inflammasome and production of IL-1β and IL-18 proinflammatory cytokines. The AIM2 mRNA levels were significantly higher in benign prostate hyperplasia (BPH) than the normal prostate. Further, human normal prostate epithelial cells (PrECs), upon becoming senescent, activated an inflammasome. Because in aging related BPH senescent PrECs accumulate, we investigated the role of POP3 and AIM2 proteins in pre-senescent and senescent PrECs. Here we report that the basal levels of the POP3 mRNA and protein were lower in senescent (versus young or old) PrECs that exhibited activation of the T1 IFN response. Further, treatment of PrECs and a BPH cell line (BPH-1) that expresses the androgen receptor (AR) with the male sex hormone dihydrotestosterone (DHT) increased the basal levels of POP3 mRNA and protein, but not AIM2, and inhibited activation of the AIM2 inflammasome. Of interest, a stable knockdown of POP3 protein expression in the BPH-1 cell line increased cytosolic DNA-induced activation of AIM2 inflammasome. These observations suggest a potential role of POP3 protein in aging-related prostatic inflammation.

Acetylation of interferon regulatory factor-5 suppresses androgen receptor and downregulates expression of Sox2

Interferon regulatory factor-5 (IRF5) is a transcription factor and has essential cellular mechanisms as a tumour suppressor gene. IRF5 protein function is irregular in various human cancers, and its role in prostate cancer is also unknown. This study presents the first evidence that IRF5 expression is controlled with androgen receptor (AR) signalling interaction and stem cell factors (Nanog, Oct4, Sox2) in prostate cancer. Human prostate cancer cell lines (PC3, DU145 and LNCaP) were transfected plasmids and assessed for cellular localization of IRF5 and AR interaction with IF-staining. Co-immunoprecipitation and ChIP assay were used to detect the IRF5 and AR protein-protein interaction and IRF5 stem cell factors protein-gene interaction. The target relation between IRF5, AR, CREB, p300, ISRE, ARE and NF-кB was tested by luciferase assay. IRF5 was low expressed in androgen-dependent prostate cancer cells and tissues. The analysis of human prostate cancer clinical samples supports the interaction of IRF5 and AR in a pathological role, as IRF5 expression is down-regulated in the tumours' advanced stages. Tumour suppression mechanism of IRF5 and SOX2 levels in cells reduces and causes AR acetylation. Those affect the prostate cancer mechanism by modifying the cellular response in the signal pathway. IRF5 can be promising for treating androgen-dependent prostate cancers and is a therapeutic protein for new drug studies.

Loss of a Negative Feedback Loop between IRF8 and AR Promotes Prostate Cancer Growth and Enzalutamide Resistance

In incurable castration-resistant prostate cancer (CRPC), resistance to the novel androgen receptor (AR) antagonist enzalutamide is driven mainly by AR overexpression. Here we report that the expression of interferon regulatory factor 8 (IRF8) is increased in primary prostate cancer but decreased in CRPC compared with normal prostate tissue. Decreased expression of IRF8 positively associated with CRPC progression and enzalutamide resistance. IRF8 interacted with AR and promoted its degradation via activation of the ubiquitin/proteasome systems. Epigenetic knockdown of IRF8 promoted AR-mediated prostate cancer progression and enzalutamide resistance in vitro and in vivo. Furthermore, IFNα increased expression of IRF8 and improved the efficacy of enzalutamide in CRPC by targeting the IRF8-AR axis. We also provide preliminary evidence for the efficacy of IFNα with hormonotherapy in a clinical study. Collectively, this study identifies IRF8 both as a tumor suppressor in prostate cancer pathogenesis and a potential alternative therapeutic option to overcome enzalutamide resistance. SIGNIFICANCE: These findings identify IRF8-mediated AR degradation as a mechanism of resistance to AR-targeted therapy, highlighting the therapeutic potential of IFNα in targeting IRF8-AR axis in CRPC. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/13/2927/F1.large.jpg.

PSMA-targeted polyinosine/polycytosine vector induces prostate tumor regression and invokes an antitumor immune response in mice

There is an urgent need for an effective treatment for metastatic prostate cancer (PC). Prostate tumors invariably overexpress prostate surface membrane antigen (PSMA). We designed a nonviral vector, PEI-PEG-DUPA (PPD), comprising polyethylenimine-polyethyleneglycol (PEI-PEG) tethered to the PSMA ligand, 2-[3-(1, 3-dicarboxy propyl)ureido] pentanedioic acid (DUPA), to treat PC. The purpose of PEI is to bind polyinosinic/polycytosinic acid (polyIC) and allow endosomal release, while DUPA targets PC cells. PolyIC activates multiple pathways that lead to tumor cell death and to the activation of bystander effects that harness the immune system against the tumor, attacking nontargeted neighboring tumor cells and reducing the probability of acquired resistance and disease recurrence. Targeting polyIC directly to tumor cells avoids the toxicity associated with systemic delivery. PPD selectively delivered polyIC into PSMA-overexpressing PC cells, inducing apoptosis, cytokine secretion, and the recruitment of human peripheral blood mononuclear cells (PBMCs). PSMA-overexpressing tumors in nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice with partially reconstituted immune systems were significantly shrunken following PPD/polyIC treatment, in all cases. Half of the tumors showed complete regression. PPD/polyIC invokes antitumor immunity, but unlike many immunotherapies does not need to be personalized for each patient. The potent antitumor effects of PPD/polyIC should spur its development for clinical use.

Antitumor activity of interferon-β1a in hormone refractory prostate cancer with neuroendocrine differentiation

PURPOSE

Type I interferons (IFN-α and IFN-β) are a class of cytokines that exert several biological activities, such as modulation of cell proliferation and differentiation and of the immune system. Although these cytokines interact with a common receptor complex, IFN-β showed a more potent antitumor activity than IFN-α in several tumor models. New recombinant human IFN-β products, such as IFN-β1a and IFN-β1b, have been produced in order to improve the stability and bioavailability of natural IFN-β. In this report, we analyzed the effects of recombinant IFN-β1a on the cell proliferation of two human androgen-resistant prostate cancer cell lines with neuroendocrine differentiation (DU-145, PC-3) and related mechanisms of action.

METHODS

The effects of IFN-β1a on the cell growth proliferation, cell cycle, and apoptosis have been evaluated in DU-145 and PC-3 cells through MTT assay, DNA flow cytometry with propidium iodide, and Annexin V-FITC/propidium iodide staining, respectively. Moreover, the expression of neuron-specific enolase (NSE), cleaved caspase-3, caspase-8, and PARP was evaluated through Western blotting.

RESULTS

IFN-β1a showed a significant anti-proliferative activity in both androgen-resistant cell lines. This effect was related to cell cycle perturbation and induction in apoptosis, as shown by flow cytometric analysis, the activation of caspase-3 and caspase-8 and PARP cleavage during incubation with IFN-β1a. Moreover, this cytokine reduced the expression of NSE in both cell lines.

CONCLUSIONS

Recombinant IFN-β1a (Rebif) showed a potent in vitro anti-proliferative activity in androgen-resistant prostate cancer cells, and it could represent a promising tool for the treatment of this tumor.

Interferon inducible antiviral MxA is inversely associated with prostate cancer and regulates cell cycle, invasion and Docetaxel induced apoptosis

BACKGROUND

The interferon inducible Myxovirus (influenza virus) resistance A (MxA) is considered as a key mediator of the interferon-induced antiviral response. Mx proteins contain the typical GTP-binding motif and show significant homology to dynamin family of GTPases. Strong interaction of MxA with tubulin suggests that Mx proteins could be involved in mitosis. Studies have shown that MxA inhibit tumor motility/metastasis and virus induced apoptosis. However, the clear association between MxA expression and cancer remains unknown. Meta-analysis suggested that MxA expression was inversely correlated with prostate cancer (PCa). In this study, we demonstrate the expression MxA in PCa and its functional significance on the cancer phenotype.

METHODS

The expression of MxA protein in prostate cancer was examined by immuno-histochemistry. MxA was knocked down (shMxA) or over-expressed (pMxA) in DU145 or LNCaP PCa cell lines respectively. These cell lines were used to study proliferation, apoptosis, invasion, migration, and anchorage independent growth. Co-localization of MxA with tubulin was performed by immuno-cytochemistry following Docetaxel treatment.

RESULTS

The expression of MxA protein was significantly decreased in PCa as compared to the normal tissues. DU145 cells lacking MxA (DU145 + chMxA) showed significant increase in proliferation, associated with decreased expression of CDKN1A and B. Increased migration, anchorage independent growth in DU145 + shMxA cells was associated with increased MMP13 expression. Tubulin organization was also dependent on MxA expression. Tubulin polymerizing agents such as Docetaxel was less effective in promoting apoptosis in cells lacking MxA due to altered tubulin organization. Gain of MxA expression in LNCaP cells (LNCaP + pMxA) resulted in cell cycle arrest that was associated with increased expression of CDKN1A. MxA expression was also down-regulated by dihydrotestosterone in LNCaP cells.

CONCLUSIONS

MxA expression is inversely correlated with prostate cancer. Down-regulation of MxA in LNCaP cells by DHT suggests that MxA could play a significant role in disease progression. Loss of MxA expression results in increased metastasis and decreased sensitivity to Docetaxel suggesting that MxA expression could determine the outcome of chemo-therapeutic treatment. Additional studies will be required to fully establish the cross-talk between androgen receptor-IFN pathway in regulating MxA expression in the normal prostate and prostate cancer. Prostate 75:266-279, 2015. © 2014 Wiley Periodicals, Inc.

In vivo biomarker expression patterns are preserved in 3D cultures of Prostate Cancer

Here we report that Prostate Cancer (PCa) cell-lines DU145, PC3, LNCaP and RWPE-1 grown in 3D matrices in contrast to conventional 2D monolayers, display distinct differences in cell morphology, proliferation and expression of important biomarker proteins associated with cancer progression. Consistent with in vivo growth rates, in 3D cultures, all PCa cell-lines were found to proliferate at significantly lower rates in comparison to their 2D counterparts. Moreover, when grown in a 3D matrix, metastatic PC3 cell-lines were found to mimic more precisely protein expression patterns of metastatic tumour formation as found in vivo. In comparison to the prostate epithelial cell-line RWPE-1, metastatic PC3 cell-lines exhibited a down-regulation of E-cadherin and α6 integrin expression and an up-regulation of N-cadherin, Vimentin and β1 integrin expression and re-expressed non-transcriptionally active AR. In comparison to the non-invasive LNCaP cell-lines, PC3 cells were found to have an up-regulation of chemokine receptor CXCR4, consistent with a metastatic phenotype. In 2D cultures, there was little distinction in protein expression between metastatic, non-invasive and epithelial cells. These results suggest that 3D cultures are more representative of in vivo morphology and may serve as a more biologically relevant model in the drug discovery pipeline.

Emerging roles for the interferon-inducible p200-family proteins in sex bias in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease involving multiple organs. The disease is characterized by the production of pathogenic autoantibodies to DNA and certain nuclear antigens, chronic inflammation, and immune dysregulation. Genetic studies involving SLE patients and mouse models have indicated that multiple lupus susceptible genes contribute to the disease phenotype. Notably, the development of SLE in patients and in certain mouse models exhibits a strong sex bias. In addition, several lines of evidence indicates that activation of interferon-α (IFN-α) signaling in immune cells and alterations in the expression of certain immunomodulatory cytokines contribute to lupus pathogenesis. Studies have implicated factors, such as the X chromosomal gene dosage effect and the sex hormones, in gender bias in SLE. However, the molecular mechanisms remain unclear. Additionally, it remains unclear whether these factors influence the "IFN-signature," which is associated with SLE. In this regard, a mutually positive regulatory feedback loop between IFNs and estrogen receptor-α (ERα) has been identified in immune cells. Moreover, studies indicate that the expression of certain IFN-inducible p200-family proteins that act as innate immune sensors for cytosolic DNA is differentially regulated by sex hormones. In this review, we discuss how the modulation of the expression of the p200-family proteins in immune cells by sex hormones and IFNs contributes to sex bias in SLE. An improved understanding of the regulation and roles of the p200-family proteins in immune cells is critical to understand lupus pathogenesis as well as response (or the lack of it) to various therapies.

Expression, regulation and function of the ISGylation system in prostate cancer

The androgen receptor (AR) plays a crucial role in the modulation of prostate cell proliferation and is involved in the development and progression of prostate cancer (PCa). An understanding of the complex regulation of AR provides novel treatment options for PCa. Here, we show (i) that the ubiquitin-like modifier, interferon-stimulated gene 15 (ISG15), and most enzymes involved in ISG15 conjugation were upregulated in tumor samples versus in non-malignant tissues of PCa patients and (ii) that the expression of these components significantly differed between tumors in patients treated with and without androgen ablation. Using PCa cell lines as in vitro models, the specific androgen-mediated, AR-dependent regulation of the ISGylation components was confirmed. In addition, the ISGylation system controls AR mRNA and protein expressions, as overexpression of Ube1L as a limiting ISGylation factor in the AR(+) androgen-sensitive PCa cell line, LNCaP, results in significant AR upregulation, accompanied by an increased proliferation even under androgen deprivation. Accordingly, Ube1L knockdown decreased the AR expression. Thus, this study describes for the first time the modulation of AR expression by ISGylation components, which affects the proliferation of PCa cells, thereby providing evidence for a novel function of the ISGylation system in malignant transformation.

Androgen-mediated cholesterol metabolism in LNCaP and PC-3 cell lines is regulated through two different isoforms of acyl-coenzyme A:Cholesterol Acyltransferase (ACAT)

BACKGROUND

The objective of this work was to determine the effect of an androgen agonist, R1881, on intracellular cholesterol synthesis and esterification in androgen-sensitive (AS) prostate cancer (LNCaP) cells.

METHODS

We investigated the activity and expression of cholesterol metabolism enzymes, HMG-CoA-reductase and ACAT in the LNCaP and PC-3 (androgen-independent control) models.

RESULTS

Microsomal PC-3 HMG-CoA-reductase activity was increased with R1881 despite having similar cholesterol levels while increased cholesterol levels in microsomes from LNCaPs treated with R1881 (L+) were associated with increased HMG-CoA reductase activity. Increased intracellular cholesteryl esters (CE) found in (L+) were not associated with an increased ACAT1 activity. There was no effect from androgen treatment on ACAT1 protein expression in theses cells; however, ACAT2 expression was induced upon R1881 treatment. In contrast, we found an increase in the in vitro ACAT1 activity in PC-3 cells treated with androgen (P+). Only ACAT1 expression was induced in P+. We further assessed the expression of STAT1 alpha, a transcriptional activator that modulates ACAT1 expression. STAT1 alpha expression and phosphorylation were induced in P+. To determine the role of the AR on ACAT1 expression and esterification, we treated PC-3 cells overexpressing the androgen receptor with R1881 (PAR+). AR expression was decreased in PAR+ cells; ACAT1 protein expression and cholesterol ester levels were also decreased, however, ACAT2 remained unchanged. STAT1 alpha expression was decreased in PAR+.

CONCLUSIONS

Overall, these findings support the importance of cholesterol metabolism regulation within prostate cancer cells and unravel a novel role for STAT1 alpha in prostate cancer metabolism.

Low-calcium serum-free defined medium selects for growth of normal prostatic epithelial stem cells

Stage-specific differentiation markers were used to evaluate the cellular composition and the origin of nonimmortalized (PrEC) and immortalized (PZ-HPV7, CA-HPV10, RWPE-1, and 957E/hTERT) human prostate cell lines. These studies documented that immortalized and nonimmortalized prostate epithelial cells established and maintained in low (i.e., <300 micromol/L) Ca(2+) serum-free defined (SFD) medium were all derived from normal nonmalignant prostate tissues and contain CD133(+)/ABCG2(+)/alpha(2)beta(1)(Hi)/p63(-)/PSCA(-)/AR(-)/PSA(-) prostate stem cells. In these cultures, prostate stem cells are able to self-renew and generate two distinct cell lineages: the minor proliferatively quiescent neuroendocrine lineage and the major transit-amplifying cell lineage. Subsequently, CD133(-)/ABCG2(-)/alpha(2)beta(1)(Hi)/p63(+)/PSCA(-)/AR(-)/PSA(-) transit-amplifying cells proliferate frequently and eventually mature into proliferatively quiescent CD133(-)/ABCG2(-)/alpha(2)beta(1)(Lo)/p63(-)/PSCA(+)/AR(-)/PSA(-) intermediate cells. Such proliferatively quiescent intermediate cells, however, do not complete their full maturation into CD133(-)/ABCG2(-)/alpha(2)beta(1)(Lo)/p63(-)/PSCA(-)/AR(+)/PSA(+) luminal-secretory cells in low Ca(2+) SFD medium. Addition of universal type I IFN and synthetic androgen (R1881) to culture medium resulted in up-regulation of androgen receptor protein expression. However, it failed to induce full differentiation of intermediate cells into AR(+)/PSA(+) luminal-secretory cells. Our results indicate that such inability of prostate epithelial cells to complete their differentiation is due to continuous expression of Notch-1 receptor and its downstream effector, Hey-1 protein, which actively suppresses differentiation via its ability to transcriptionally repress a series of genes, including the GATA family of transcription factors.