Y08197 is a novel and selective CBP/EP300 bromodomain inhibitor for the treatment of prostate cancer.

In advanced prostate cancer, CREB (cAMP-responsive element-binding protein) binding protein (CBP) and its homolog EP300 are highly expressed; targeting the bromodomain of CBP is a new strategy for the treatment of prostate cancer. In the current study we identified Y08197, a novel 1-(indolizin-3-yl) ethanone derivative, as a selective inhibitor of CBP/EP300 bromodomain and explored its antitumor activity against prostate cancer cell lines in vitro. In the AlphaScreen assay, we demonstrated that Y08197 dose-dependently inhibited the CBP bromodomain with an IC50 value at 100.67 ± 3.30 nM. Y08197 also exhibited high selectivity for CBP/EP300 over other bromodomain-containing proteins. In LNCaP, 22Rv1 and VCaP prostate cancer cells, treatment with Y08197 (1, 5 µM) strongly affected downstream signaling transduction, thus markedly inhibiting the expression of androgen receptor (AR)-regulated genes PSA, KLK2, TMPRSS2, and oncogenes C-MYC and ERG. Notably, Y08197 potently inhibited cell growth in several AR-positive prostate cancer cell lines including LNCaP, 22Rv1, VCaP, and C4-2B. In 22Rv1 prostate cancer cells, treatment with Y08197 (1, 4, 16 µM) dose-dependently induced G0/G1 phase arrest and apoptosis. Furthermore, treatment with Y08197 (5 µM) significantly decreased ERG-induced invasive capacity of 22Rv1 prostate cancer cells detected in wound-healing assay and cell migration assay. Taken together, CBP/EP300 inhibitor Y08197 represents a promising lead compound for development as new therapeutics for the treatment of castration-resistant prostate cancer.

Discovery and structural optimization of 4-(4-(benzyloxy)phenyl)-3,4-dihydropyrimidin-2(1H)-ones as RORc inverse agonists.

AIM: Retinoic acid receptor-related orphan nuclear receptors (RORs) are orphan nuclear receptors that show constitutive activity in the absence of ligands. Among 3 subtypes of RORs, RORc is a promising therapeutic target for the treatment of Th17-mediated autoimmune diseases. Here, we report novel RORc inverse agonists discovered through structure-based drug design. METHODS: Based on the structure of compound 8, a previously described agonist of RORa, a series of 4-(4-(benzyloxy)phenyl)-3,4-dihydropyrimidin-2(1H)-one derivatives were designed and synthesized. The interaction between the compounds and RORc was detected at molecular level using AlphaScreen assay. The compounds were further examined in 293T cells transfected with RORc and luciferase reporter gene. Thermal stability shift assay was used to evaluate the effects of the compounds on protein stability. RESULTS: A total of 27 derivatives were designed and synthesized. Among them, the compound 22b was identified as the most potent RORc inverse agonist. Its IC50 values were 2.39 µmol/L in AlphaScreen assay, and 0.82 µmol/L in inhibition of the cell-based luciferase reporter activity. Furthermore, the compound 22b displayed a 120-fold selectivity for RORc over other nuclear receptors. Moreover, a molecular docking study showed that the structure-activity relationship was consistent with the binding mode of compound 22b in RORc. CONCLUSION: 4-(4-(Benzyloxy)phenyl)-3,4-dihydropyrimidin-2(1H)-one derivatives are promising candidates for the treatment of Th17-mediated autoimmune diseases, such as rheumatoid arthritis, psoriasis, and multiple sclerosis.

Effects of fluoride on the intracellular free Ca2+ and Ca2+-ATPase of kidney.

In the present study, the effect of fluoride on intracellular free calcium ([Ca2+]i) and Ca2+-ATPase of renal cells were examined. Some paradoxical experimental results about the mechanism of fluoride toxicity were observed. In vivo, 48 Wistar rats were divided into 4 groups, and half of rats were treated with sodium fluoride (NaF) by drinking water (per liter of tap water containing 100 mg F-). Compared with the respective control, the level of [Ca2+]i of the kidney in two fluoride-treated rats obviously increased (p < 0.05); and the activity of Ca2+-ATPase in 100 mg F-/L groups with a standard diet did not significantly increase, and the enzyme activity in 100-mg F-/L group with a low-calcium diet decreased significantly compared to the 100 mg F-/L group with a standard diet (p < 0.05). In vitro, renal tubular cells were cultured and respectively exposed to 1.0, 5.0, 7.5, and 12.5 mg/L fluoride in the culture medium. Results showed the significantly elevated activity of Ca2+-ATPase in the cells exposed to 1.0 and 5.0 mg/L fluoride (p < 0.05), and this enzyme activity indicated inhibitory trend in cells of the 7.5- and 12.5-mg/L fluoride-treated group. To sum up, the effect of fluoride on Ca2+-ATPase is a similar to a dose-effect relationship phenomenon characterized by low-dose stimulation and high-dose inhibition, and the increase of [Ca2+]i probably plays a key role on the mechanism of renal injury in fluorosis.

Role of endoplasmic reticulum stress in aberrant activation of fluoride-treated osteoblasts.

The aberrant activation of osteoblasts in the early stage is one of the critical steps during the pathogenesis of skeletal fluorosis. The endoplasmic reticulum (ER) stresses and unfolded protein response (UPR) are initiated to alleviate the accumulation of unfolded proteins against cell injury. The previous researches had demonstrated that fluoride induced ER stress in other cells or tissues. In this study, we determined the ER stress and UPR to investigate their roles in aberrant activation of fluoride-treated osteoblasts. The gene expression of bone markers and UPR factors in MC3T3-E1 cells treated with varying doses of fluoride administration was analyzed. Meantime, levels of glutathione and glutathione disulfide were tested by the ultraperformance liquid chromatography-tandem mass spectrometry applications. Our results indicated that a certain dose and period of fluoride administration induced cell proliferation and differentiation, and Runx2 was involved in the regulation of osteoblastic differentiation of MC3T3-E1 cells. Increase trend of Runx2 expression was consistent with change of marker of ER stress. Fluoride caused ER stress and stimulated UPR during the process of osteoblast maturation, while oxidative stress was also active in the occurrence of ER stress. These data indicated that ER stress and UPR were possibly involved in the action of fluoride on osteoblasts.

[Detection of antigen-receptor gene rearrangement clonality for diagnosis of lymphoma].

This study was aimed to investigate the significance of detecting the antigen-receptor gene rearrangement clonality in the diagnosis of lymphoma. Paraffin-embedding and HE staining of samples from 31 patients with lymphomas were performed for morphologic observation by light microscope. Immunophenotype was analyzed by the immunohistochemistry (IHC) method. The clonality of antigen-receptor gene rearrangement was detected by BIOMED-2 Assay Kit. The results showed that among the 31 cases, 12 cases were suspected to be T-cell lymphoma, 1 case was suspected to be T-cell reactive hyperplasia, and 16 cases were suspected to be B-cell lymphoma, 2 cases were B-cell reactive hyperplasia. The detection results showed that the positivity of Ig gene rearrangement clonality was 94.44% (17/18), the positivity of TCR gene rearrangement clonality was 92.31% (12/13), the other two cases were negative. Finally, 12 cases were diagnosed to be T-cell lymphoma and 17 cases were B-cell lymphoma. The other two cases were reactive lymphoid proliferations. And the positivity rate in the 31 patients with lymphomas was 93%. It is concluded that the detection of antigen-receptor gene rearrangement clonality is a useful assistant method in the diagnosis of lymphoma.

Activation of PERK signaling through fluoride-mediated endoplasmic reticulum stress in OS732 cells.

Our proteomical analysis of osteoblasts exposed to fluoride revealed a distinctive upregulation of proteins in osteoblast. These upregulated proteins play key roles in the protein folding. The PRK-like ER kinase (PERK) signaling, one branch of unfolded protein response (UPR) to combat ER stress, is a transcription factor needed for osteoblast proliferation and differentiation. The mechanism of skeletal fluorosis by which fluoride regulates osteoblast is not fully defined. Here we studied the effect of fluoride on PERK signaling genes and x-box binding protein 1 (xbp-1) in OS7232 cells (human osteoblast-like cell line). Meantime, genes associated with bone turnover were examined in this study. We found that early and continuous fluoride exposure increased the binding immunoglobulin protein (BiP) expression and activated the PERK signaling pathway, resulting in activation of transcription factor 4 (ATF4) and nuclear factor erythroid 2-related factor 2 (Nrf2). The altered expression of cbfa1, osteoprotegerin (OPG)/nuclear factor kappa B ligand (RANKL) were viewed in this study. These results showed fluoride impelled a distinctive ER stress response in OS732 cells, primarily by activating PERK and PERK-dependent signaling. Little effects were viewed for activating xbp-1, a common target of the other two canonical sensors of ER stress, ATF6 and IRE1. In this study the altered expression of bone turnover genes were consistent with activation of ER stress and PERK signaling. This study proved that PERK signaling play major roles in action of fluoride on osteoblast, and suggested that bone response in skeletal fluorosis may be due in part to PERK signaling pathway.