Androgen receptor (AR) mediates the growth of prostate cancer (PCa) throughout its course of development, including in abnormal splice variants (AR-SV)-driven advanced stage castration-resistant disease. AR stabilization by androgens makes it distinct from other steroid receptors, which are typically ubiquitinated and degraded by proteasomes after ligand binding. Thus, targeting AR in advanced PCa requires the development of agents that can sustainably degrade variant isoforms for effective therapy. Here we report the discovery and characterization of potent selective AR degraders (SARDs) that markedly reduce the activity of wildtype and splice variant isoforms of AR at sub-micromolar doses. Three SARDs (UT-69, UT-155, and (R)-UT-155) bind the amino-terminal transcriptional activation domain AF-1, which has not been targeted for degradation previously, with two of these SARD (UT-69 and UT-155) also binding the carboxy-terminal ligand binding domain. Despite different mechanisms of action, all three SARDs degraded wild-type AR and inhibited AR function, exhibiting greater inhibitory potency than the approved AR antagonists. Collectively, our results introduce a new candidate class of next-generation therapeutics to manage advanced PCa.

Nearly one half of patients with lupus develop glomerulonephritis (GN), which often leads to renal failure. Although nephritis is diagnosed by the presence of proteinuria, the pathology of nephritis can fall into one of five classes defined by different forms of tissue injury, and the mechanisms involved in pathogenesis are not completely understood. Glycosphingolipids are abundant in the kidney, have roles in many cellular functions, and were shown to be involved in other renal diseases. Here, we show dysfunctional glycosphingolipid metabolism in patients with lupus nephritis and MRL/lpr lupus mice. Specifically, we found that glucosylceramide (GlcCer) and lactosylceramide (LacCer) levels are significantly higher in the kidneys of nephritic MRL/lpr lupus mice than the kidneys of non-nephritic lupus mice or healthy controls. This elevation may be, in part, caused by altered transcriptional regulation and/or activity of LacCer synthase (GalT5) and neuraminidase 1, enzymes that mediate glycosphingolipid metabolism. We show increased neuraminidase 1 activity early during the progression of nephritis (before significant elevation of GlcCer and LacCer in the kidney). Elevated levels of urinary LacCer were detected before proteinuria in lupus mice. Notably, LacCer levels were higher in the urine and kidneys of patients with lupus and nephritis than patients with lupus without nephritis or healthy controls. Together, these results show early and significant dysfunction of the glycosphingolipid metabolic pathway in the kidneys of lupus mice and patients with lupus nephritis and suggest that molecules in this pathway may serve as early markers in lupus nephritis.

Purpose: Androgen receptor (AR)-targeting prostate cancer drugs, which are predominantly competitive ligand-binding domain (LBD)-binding antagonists, are inactivated by common resistance mechanisms. It is important to develop next-generation mechanistically distinct drugs to treat castration-and drug-resistant prostate cancers.Experimental Design: Second-generation AR pan antagonist UT-34 was selected from a library of compounds and tested in competitive AR binding and transactivation assays. UT-34 was tested using biophysical methods for binding to the AR activation function-1 (AF-1) domain. Western blot, gene expression, and proliferation assays were performed in various AR-positive enzalutamidesensitive and -resistant prostate cancer cell lines. Pharmacokinetic and xenograft studies were performed in immunocompromised rats and mice.Results: UT-34 inhibits the wild-type and LBD-mutant ARs comparably and inhibits the in vitro proliferation and in vivo growth of enzalutamide-sensitive and -resistant prostate cancer xenografts. In preclinical models, UT-34 induced the regression of enzalutamide-resistant tumors at doses when the AR is degraded; but, at lower doses, when the AR is just antagonized, it inhibits, without shrinking, the tumors. This indicates that degradation might be a prerequisite for tumor regression. Mechanistically, UT-34 promotes a conformation that is distinct from the LBD-binding competitive antagonist enzalutamide and degrades the AR through the ubiquitin proteasome mechanism. UT-34 has a broad safety margin and exhibits no cross-reactivity with Gprotein-coupled receptor kinase and nuclear receptor family members.Conclusions: Collectively, UT-34 exhibits the properties necessary for a next-generation prostate cancer drug.

In our effort to find small-molecule treatments of advanced prostate cancers (PCs), a novel series of indolyl and indolinyl propanamides (series II and III) were discovered as selective androgen receptor degraders (SARDs). Initial studies of androgen receptor (AR) antagonist (1) and agonist (2) propanamides yielded a tertiary aniline (3) with novel SARD activity but poor metabolic stability. Cyclization to II and III produced submicromolar AR antagonism and protein degradation selective to AR and AR splice variant (AR SV). II and III maintained potency against enzalutamide-resistant (Enz-R) mutant ARs and PC cells and were efficacious in Enz-R xenografts, suggesting their potential to treat advanced PCs. Design, synthesis, and biological activity of novel SARDs that could potentially be used for the treatment of a wide spectrum of PCs including castration-resistant, Enz-R, and/or AR SV-dependent advanced PCs that are often untreatable with known hormone therapies are discussed.

Most satiety-inducing obesity therapeutics, despite modest efficacy, have safety concerns that underscore the need for effective peripherally acting drugs. An attractive therapeutic approach for obesity is to optimize/maximize energy expenditure by increasing energy-utilizing thermogenic brown adipose tissue. We used in vivo and in vitro models to determine the role of estrogen receptor β (ER-β) and its ligands on adipose biology. RNA sequencing and metabolomics were used to determine the mechanism of action of ER-β and its ligands. Estrogen receptor β (ER-β) and its selective ligand reprogrammed preadipocytes and precursor stem cells into brown adipose tissue and increased mitochondrial respiration. An ER-β-selective ligand increased markers of tricarboxylic acid-dependent and -independent energy biogenesis and oxygen consumption in mice without a concomitant increase in physical activity or food consumption, all culminating in significantly reduced weight gain and adiposity. The antiobesity effects of ER-β ligand were not observed in ER-β-knockout mice. Serum metabolite profiles of adult lean and juvenile mice were comparable, while that of adult obese mice was distinct, indicating a possible impact of obesity on age-dependent metabolism. This phenotype was partially reversed by ER-β-selective ligand. These data highlight a new role for ER-β in adipose biology and its potential to be a safer alternative peripheral therapeutic target for obesity.-Ponnusamy, S., Tran, Q. T., Harvey, I., Smallwood, H. S., Thiyagarajan, T., Banerjee, S., Johnson, D. L., Dalton, J. T., Sullivan, R. D., Miller, D. D., Bridges, D., Narayanan, R. Pharmacologic activation of estrogen receptor β increases mitochondrial function, energy expenditure, and brown adipose tissue.

The Na+-Ca2+ exchanger gene (Ncx1) is upregulated in hypertrophy and is often found elevated in end-stage heart failure. Studies have shown that the change in its expression contributes to contractile dysfunction. β-adrenergic receptor (β-AR) signaling plays an important role in the regulation of calcium homeostasis in the cardiomyocyte but chronic activation in periods of cardiac stress contribute to heart failure by mechanisms which include Ncx1 upregulation. Here, using a Ca2+/Calmodulin-Dependent Protein Kinase II (CaMKIIδc) null mouse, we demonstrate that β-AR-stimulated Ncx1 upregulation is dependent on CaMKII. β-AR-stimulated Ncx1 expression is mediated by activator protein 1 (AP-1) factors and is independent of cAMP-response element-binding protein (CREB) activation. The MAP kinases (ERK1/2, JNK and p38) are not required for AP-1 factor activation. Chromatin immunoprecipitation demonstrates that β-AR stimulation activates the ordered recruitment of JunB homodimers which then are replaced by c-Jun homodimers binding to the proximal AP-1 elements of the endogenous Ncx1 promoter. In conclusion, this work has provided insight into the intracellular signaling pathways and transcription factors regulating Ncx1 gene expression in a chronically β-AR-stimulated heart.

Systemic Lupus erythematosus (SLE) is an autoimmune disease caused, in part, by abnormalities in cells of the immune system including B and T cells. Genetically reducing globally the expression of the ETS transcription factor FLI1 by 50% in two lupus mouse models significantly improves disease measures and survival through an unknown mechanism. In this study we analyze the effects of reducing FLI1 in the MRL/lpr lupus prone model on T cell function. We demonstrate that adoptive transfer of MRL/lpr Fli1 +/+ or Fli1 +/- T cells and B cells into Rag1-deficient mice results in significantly decreased serum immunoglobulin levels in animals receiving Fli1 +/- lupus T cells compared to animals receiving Fli1 +/+ lupus T cells regardless of the genotype of co-transferred lupus B cells. Ex vivo analyses of MRL/lpr T cells demonstrated that Fli1 +/- T cells produce significantly less IL-4 during early and late disease and exhibited significantly decreased TCR-specific activation during early disease compared to Fli1 +/+ T cells. Moreover, the Fli1 +/- T cells expressed significantly less neuraminidase 1 (Neu1) message and decreased NEU activity during early disease and significantly decreased levels of glycosphingolipids during late disease compared to Fli1 +/+ T cells. FLI1 dose-dependently activated the Neu1 promoter in mouse and human T cell lines. Together, our results suggest reducing FLI1 in lupus decreases the pathogenicity of T cells by decreasing TCR-specific activation and IL-4 production in part through the modulation of glycosphingolipid metabolism. Reducing the expression of FLI1 or targeting the glycosphingolipid metabolic pathway in lupus may serve as a therapeutic approach to treating lupus.

It is becoming increasingly evident that histone deacetylases (HDACs) have a prominent role in the alteration of gene expression during the growth remodeling process of cardiac hypertrophy. HDACs are generally viewed as corepressors of gene expression. However, we demonstrate that class I and class II HDACs play an important role in the basal expression and up-regulation of the sodium calcium exchanger (Ncx1) gene in adult cardiomyocytes. Treatment with the HDAC inhibitor trichostatin A (TSA) prevented the pressure-overload-stimulated up-regulation of Ncx1 expression. Overexpression of HDAC5 resulted in the dose-dependent up-regulation of basal and alpha-adrenergic stimulated Ncx1 expression. We show that Nkx2.5 recruits HDAC5 to the Ncx1 promoter, where HDAC5 complexes with HDAC1. Nkx2.5 also interacts with transcriptional activator p300, which is recruited to the Ncx1 promoter. We demonstrate that when Nkx2.5 is acetylated, it is found associated with HDAC5, whereas deacetylated Nkx2.5 is in complex with p300. Notably, TSA treatment prevents p300 from being recruited to the endogenous Ncx1 promoter, resulting in the repression of Ncx1 expression. We propose a novel model for Ncx1 regulation in which deacetylation of Nkx2.5 is required for the recruitment of p300 and results in up-regulation of exchanger expression.