Association between the serum uric acid levels and prostate cancer: evidence from National Health and Nutrition Examination Survey (NHANES) 1999-2010.

Background: Uric acid may play a critical role in protection against cancer by the suppression of inflammation. The association between serum uric acid (SUA) levels and prostate cancer risk is debatable yet has received little attention in the American population. Therefore, we used data from the National Health and Nutrition Examination Survey (NHANES) to determine their correlation. Methods: Using information from NHANES 1999-2010, a total of 62,160 individuals from the general population were included in this cross-sectional study. Additionally, a number of covariates were acquired. Prostate cancer was used to divide the participants into two groups: prostate cancer group (n=315) and non-prostate cancer group (n=7,545). A weighted adjusted logistic regression analysis was conducted to examine the potential correlation between SUA and prostate cancer. Results: Our study comprised a total of 7,860 participants. After full adjustment for confounders, SUA was not significantly associated with prostate cancer [odds ratio (OR) 0.91, 95% confidence interval (CI): 0.82-1.00, P=0.058]. In participants aged 60 years and above (≥60 years), a higher SUA was significantly associated with a lower risk of prostate cancer (OR 0.88, 95% CI: 0.80-0.96, P=0.003). However, among those younger than 60 years (<60 years), there was no association between SUA and prostate cancer risk (OR 1.29, 95% CI: 0.69-2.42, P=0.42). In addition, in the subgroup analysis stratified by body mass index, hypertension and diabetes, there was no significant correlation between SUA and prostate cancer. Conclusions: SUA is negatively associated with the risk of prostate cancer in older men, especially for those 60 years of age and beyond.

An Enzyme-Cleavable Solubilizing-Tag Facilitates the Chemical Synthesis of Mirror-Image Proteins.

Mirror-image proteins (D-proteins) are useful in biomedical research for purposes such as mirror-image screening for D-peptide drug discovery, but the chemical synthesis of many D-proteins is often low yielding due to the poor solubility or aggregation of their constituent peptide segments. Here, we report a Lys-C protease-cleavable solubilizing tag and its use to synthesize difficult-to-obtain D-proteins. Our tag is easily installed onto multiple amino acids such as DLys, DSer, DThr, and/or the N-terminal amino acid of hydrophobic D-peptides, is impervious to various reaction conditions, such as peptide synthesis, ligation, desulfurization, and transition metal-mediated deprotection, and yet can be completely removed by Lys-C protease under denaturing conditions to give the desired D-protein. The efficacy and practicality of the new method were exemplified in the synthesis of two challenging D-proteins: D-enantiomers of programmed cell death protein 1 IgV domain and SARS-CoV-2 envelope protein, in high yield. This work demonstrates that the enzymatic cleavage of solubilizing tags under denaturing conditions is feasible, thus paving the way for the production of more D-proteins.

L-Glycosidase-Cleavable Natural Glycans Facilitate the Chemical Synthesis of Correctly Folded Disulfide-Bonded D-Proteins.

D-peptide ligands can be screened for therapeutic potency and enzymatic stability using synthetic mirror-image proteins (D-proteins), but efficient acquisition of these D-proteins can be hampered by the need to accomplish their in vitro folding, which often requires the formation of correctly linked disulfide bonds. Here, we report the finding that temporary installation of natural O-linked-ß-N-acetyl-D-glucosamine (O-GlcNAc) groups onto selected D-serine or D-threonine residues of the synthetic disulfide-bonded D-proteins can facilitate their folding in vitro, and that the natural glycosyl groups can be completely removed from the folded D-proteins to afford the desired chirally inverted D-protein targets using naturally occurring O-GlcNAcase. This approach enabled the efficient chemical syntheses of several important but difficult-to-fold D-proteins incorporating disulfide bonds including the mirror-image tumor necrosis factor alpha (D-TNFα) homotrimer and the mirror-image receptor-binding domain of the Omicron spike protein (D-RBD). Our work establishes the use of O-GlcNAc to facilitate D-protein synthesis and folding and proves that D-proteins bearing O-GlcNAc can be good substrates for naturally occurring O-GlcNAcase.

Backbone-Installed Split Intein-Assisted Ligation for the Chemical Synthesis of Mirror-Image Proteins.

Membrane-associated D-proteins are an important class of synthetic molecules needed for D-peptide drug discovery, but their chemical synthesis using canonical ligation methods such as native chemical ligation is often hampered by the poor solubility of their constituent peptide segments. Here, we describe a Backbone-Installed Split Intein-Assisted Ligation (BISIAL) method for the synthesis of these proteins, wherein the native L-forms of the N- and C-intein fragments of the unique consensus-fast (Cfa) (i.e. L-CfaN and L-CfaC ) are separately installed onto the two D-peptide segments to be ligated via a removable backbone modification. The ligation proceeds smoothly at micromolar (µM) concentrations under strongly chaotropic conditions (8.0 M urea), and the subsequent removal of the backbone modification groups affords the desired D-proteins without leaving any "ligation scar" on the products. The effectiveness and practicality of the BISIAL method are exemplified by the synthesis of the D-enantiomers of the extracellular domains of T cell immunoglobulin and ITIM domain (TIGIT) and tropomyosin receptor kinase C (TrkC). The BISIAL method further expands the chemical protein synthesis ligation toolkit and provides practical access to challenging D-protein targets.

Chemical Synthesis of a Full-Length G-Protein-Coupled Receptor ß2-Adrenergic Receptor with Defined Modification Patterns at the C-Terminus.

The ß2-adrenergic receptor (ß2AR) is a G-protein-coupled receptor (GPCR) that responds to the hormone adrenaline and is an important drug target in the context of respiratory diseases, including asthma. ß2AR function can be regulated by post-translational modifications such as phosphorylation and ubiquitination at the C-terminus, but access to the full-length ß2AR with well-defined and homogeneous modification patterns critical for biochemical and biophysical studies remains challenging. Here, we report a practical synthesis of differentially modified, full-length ß2AR based on a combined native chemical ligation (NCL) and sortase ligation strategy. An array of homogeneous samples of full-length ß2ARs with distinct modification patterns, including a full-length ß2AR bearing both monoubiquitination and octaphosphorylation modifications, were successfully prepared for the first time. Using these homogeneously modified full-length ß2AR receptors, we found that different phosphorylation patterns mediate different interactions with ß-arrestin1 as reflected in different agonist binding affinities. Our experiments also indicated that ubiquitination can further modulate interactions between ß2AR and ß-arrestin1. Access to full-length ß2AR with well-defined and homogeneous modification patterns at the C-terminus opens a door to further in-depth mechanistic studies into the structure and dynamics of ß2AR complexes with downstream transducer proteins, including G proteins, arrestins, and GPCR kinases.

Predicting pubic arch interference in permanent prostate brachytherapy based on the specific parameters derived from nuclear magnetic resonance imaging.

PURPOSE: The aim of this study was to establish a more reliable method to predict pubic arch interference (PAI) before permanent prostate brachytherapy. MATERIAL AND METHODS: We retrospectively analyzed the nuclear magnetic resonance imaging (MRI) results of forty patients with prostate cancer, who were treated with permanent implantation of 125I seeds (permanent brachytherapy). We measured and calculated six parameters based on the MRI results: 1. The prostate volume (PV); 2. The angle of the pubic arch (AoPA); 3. The angle of PAI (AoPAI, pubic symphysis level); 4. The height of PAI (hPAI, pubic symphysis level); 5. The maximum angle of PAI (AoPAIMax); 6. The maximum height of PAI (hPAIMax). We then tested which parameters could accurately predict PAI through receiver operating characteristic (ROC) curve analysis. RESULTS: The results of this study demonstrated that AoPAI, hPAI, hPAIMax, and AoPAIMax could predict PAI. Out of forty cases in our research, 10 cases were with PAI and 30 cases without PAI during the operation. The areas under the ROC curve for PV, AoPA, AoPAI (pubic symphysis level), hPAI (pubic symphysis level), AoPAIMax, and hPAIMax were 0.592, 0.567, 0.957, 0.940, 0.927, and 0.877, respectively. The AoPAI (pubic symphysis level), hPAI (pubic symphysis level), AoPAIMax, and hPAIMax were statistically correlated with PAI. The boundary values were 26.32°, 1.13 cm, 28.37°, and 1.51 cm, respectively. CONCLUSIONS: This new method derived from MRI has predictive value, as AoPAI, hPAI, hPAIMax, and AoPAIMax could predict PAI. Taking other factors into consideration, we suggest the use of AoPAI as a novel and very reliable predictor of PAI.

Mutant-IDH1-dependent chromatin state reprogramming, reversibility, and persistence.

Mutations in IDH1 and IDH2 (encoding isocitrate dehydrogenase 1 and 2) drive the development of gliomas and other human malignancies. Mutant IDH1 induces epigenetic changes that promote tumorigenesis, but the scale and reversibility of these changes are unknown. Here, using human astrocyte and glioma tumorsphere systems, we generate a large-scale atlas of mutant-IDH1-induced epigenomic reprogramming. We characterize the reversibility of the alterations in DNA methylation, the histone landscape, and transcriptional reprogramming that occur following IDH1 mutation. We discover genome-wide coordinate changes in the localization and intensity of multiple histone marks and chromatin states. Mutant IDH1 establishes a CD24+ population with a proliferative advantage and stem-like transcriptional features. Strikingly, prolonged exposure to mutant IDH1 results in irreversible genomic and epigenetic alterations. Together, these observations provide unprecedented high-resolution molecular portraits of mutant-IDH1-dependent epigenomic reprogramming. These findings have substantial implications for understanding of mutant IDH function and for optimizing therapeutic approaches to targeting IDH-mutant tumors.

UTX/KDM6A Loss Enhances the Malignant Phenotype of Multiple Myeloma and Sensitizes Cells to EZH2 inhibition.

Loss or inactivation of the histone H3K27 demethylase UTX occurs in several malignancies, including multiple myeloma (MM). Using an isogenic cell system, we found that loss of UTX leads to deactivation of gene expression ultimately promoting the proliferation, clonogenicity, adhesion, and tumorigenicity of MM cells. Moreover, UTX mutant cells showed increased in vitro and in vivo sensitivity to inhibition of EZH2, a histone methyltransferase that generates H3K27me3. Such sensitivity was related to a decrease in the levels of IRF4 and c-MYC and an activation of repressors of IRF4 characteristic of germinal center B cells such as BCL6 and IRF1. Rebalance of H3K27me3 levels at specific genes through EZH2 inhibitors may be a therapeutic strategy in MM cases harboring UTX mutations.

Unabridged Analysis of Human Histone H3 by Differential Top-Down Mass Spectrometry Reveals Hypermethylated Proteoforms from MMSET/NSD2 Overexpression.

Histones, and their modifications, are critical components of cellular programming and epigenetic inheritance. Recently, cancer genome sequencing has uncovered driver mutations in chromatin modifying enzymes spurring high interest how such mutations change histone modification patterns. Here, we applied Top-Down mass spectrometry for the characterization of combinatorial modifications (i.e. methylation and acetylation) on full length histone H3 from human cell lines derived from multiple myeloma patients with overexpression of the histone methyltransferase MMSET as the result of a t(4;14) chromosomal translocation. Using the latest in Orbitrap-based technology for clean isolation of isobaric proteoforms containing up to 10 methylations and/or up to two acetylations, we provide extensive characterization of histone H3.1 and H3.3 proteoforms. Differential analysis of modifications by electron-based dissociation recapitulated antagonistic crosstalk between K27 and K36 methylation in H3.1, validating that full-length histone H3 (15 kDa) can be analyzed with site-specific assignments for multiple modifications. It also revealed K36 methylation in H3.3 was affected less by the overexpression of MMSET because of its higher methylation levels in control cells. The co-occurrence of acetylation with a minimum of three methyl groups in H3K9 and H3K27 suggested a hierarchy in the addition of certain modifications. Comparative analysis showed that high levels of MMSET in the myeloma-like cells drove the formation of hypermethyled proteoforms containing H3K36me2 co-existent with the repressive marks H3K9me2/3 and H3K27me2/3. Unique histone proteoforms with such "trivalent hypermethylation" (K9me2/3-K27me2/3-K36me2) were not discovered when H3.1 peptides were analyzed by Bottom-Up. Such disease-correlated proteoforms could link tightly to aberrant transcription programs driving cellular proliferation, and their precise description demonstrates that Top-Down mass spectrometry can now decode crosstalk involving up to three modified sites.

Histone methyltransferase MMSET/NSD2 alters EZH2 binding and reprograms the myeloma epigenome through global and focal changes in H3K36 and H3K27 methylation.

Overexpression of the histone methyltransferase MMSET in t(4;14)+ multiple myeloma patients is believed to be the driving factor in the pathogenesis of this subtype of myeloma. MMSET catalyzes dimethylation of lysine 36 on histone H3 (H3K36me2), and its overexpression causes a global increase in H3K36me2, redistributing this mark in a broad, elevated level across the genome. Here, we demonstrate that an increased level of MMSET also induces a global reduction of lysine 27 trimethylation on histone H3 (H3K27me3). Despite the net decrease in H3K27 methylation, specific genomic loci exhibit enhanced recruitment of the EZH2 histone methyltransferase and become hypermethylated on this residue. These effects likely contribute to the myeloma phenotype since MMSET-overexpressing cells displayed increased sensitivity to EZH2 inhibition. Furthermore, we demonstrate that such MMSET-mediated epigenetic changes require a number of functional domains within the protein, including PHD domains that mediate MMSET recruitment to chromatin. In vivo, targeting of MMSET by an inducible shRNA reversed histone methylation changes and led to regression of established tumors in athymic mice. Together, our work elucidates previously unrecognized interplay between MMSET and EZH2 in myeloma oncogenesis and identifies domains to be considered when designing inhibitors of MMSET function.

Proteomics guided discovery of flavopeptins: anti-proliferative aldehydes synthesized by a reductase domain-containing non-ribosomal peptide synthetase.

Due to the importance of proteases in regulating cellular processes, the development of protease inhibitors has garnered great attention. Peptide-based aldehydes are a class of compounds that exhibit inhibitory activities against various proteases and proteasomes in the context of anti-proliferative treatments for cancer and other diseases. More than a dozen peptide-based natural products containing aldehydes have been discovered such as chymostatin, leupeptin, and fellutamide; however, the biosynthetic origin of the aldehyde functionality has yet to be elucidated. Herein we describe the discovery of a new group of lipopeptide aldehydes, the flavopeptins, and the corresponding biosynthetic pathway arising from an orphan gene cluster in Streptomyces sp. NRRL-F6652, a close relative of Streptomyces flavogriseus ATCC 33331. This research was initiated using a proteomics approach that screens for expressed enzymes involved in secondary metabolism in microorganisms. Flavopeptins are synthesized through a non-ribosomal peptide synthetase containing a terminal NAD(P)H-dependent reductase domain likely for the reductive release of the peptide with a C-terminal aldehyde. Solid-phase peptide synthesis of several flavopeptin species and derivatives enabled structural verification and subsequent screening of biological activity. Flavopeptins exhibit sub-micromolar inhibition activities against cysteine proteases such as papain and calpain as well as the human 20S proteasome. They also show anti-proliferative activities against multiple myeloma and lymphoma cell lines.

Oncogene-induced cellular senescence elicits an anti-Warburg effect.

Cellular senescence, an irreversible cell cycle arrest induced by a diversity of stimuli, has been considered as an innate tumor suppressing mechanism with implications and applications in cancer therapy. Using a targeted proteomics approach, we show that fibroblasts induced into senescence by expression of oncogenic Ras exhibit a decrease of global acetylation on all core histones, consistent with formation of senescence-associated heterochromatic foci. We also detected clear increases in repressive markers (e.g. >50% elevation of H3K27me2/3) along with decreases in histone marks associated with increased transcriptional expression/elongation (e.g. H3K36me2/3). Despite the increases in repressive marks of chromatin, 179 loci (of 2206 total) were found to be upregulated by global quantitative proteomics. The changes in the cytosolic proteome indicated an upregulation of mitochondrial proteins and downregulation of proteins involved in glycolysis. These alterations in primary metabolism are opposite to the well-known Warburg effect observed in cancer cells. This study significantly improves our understanding of stress-induced senescence and provides a potential application for triggering it in antiproliferative strategies that target the primary metabolism in cancer cells.

EZH2 is required for germinal center formation and somatic EZH2 mutations promote lymphoid transformation.

The EZH2 histone methyltransferase is highly expressed in germinal center (GC) B cells and targeted by somatic mutations in B cell lymphomas. Here, we find that EZH2 deletion or pharmacologic inhibition suppresses GC formation and functions. EZH2 represses proliferation checkpoint genes and helps establish bivalent chromatin domains at key regulatory loci to transiently suppress GC B cell differentiation. Somatic mutations reinforce these physiological effects through enhanced silencing of EZH2 targets. Conditional expression of mutant EZH2 in mice induces GC hyperplasia and accelerated lymphomagenesis in cooperation with BCL2. GC B cell (GCB)-type diffuse large B cell lymphomas (DLBCLs) are mostly addicted to EZH2 but not the more differentiated activated B cell (ABC)-type DLBCLs, thus clarifying the therapeutic scope of EZH2 targeting.

Fusion between TMPRSS2 and ETS family members (ERG, ETV1, ETV4) in prostate cancers from northern China.

In this study we evaluated the frequency of fusion between TMPRSS2 and ETS family members (ERG, ETV1, ETV4) in prostate cancers in patients from northern China in order to explore differences in fusion rates among regions in northern and southern China, other parts of Asia, Europe, and North America. We examined 100 prostate cancer patients, diagnosed by means of prostate biopsy; fluorescence in situ hybridization (FISH) was used to detect the expression of TMPRSS2, ERG, ETV1 and ETV4 in cancer tissue. Differences in gene fusion rates among different ethnics groups were also analyzed. Of the 100 prostate cancer patients, 55 (55%) had the fusion gene. Among the patients with the fusion gene, 46 (83.6%) patients had the TMPRSS2:ERG fusion product, 8 (14.8%) patients had TMPRSS2:ETV1 fusion, 1 (1.6%) patient had TMPRSS2:ETV4.

[The indication of bone scan for patients with newly diagnosed prostate cancer].

OBJECTIVE: To investigate the indication of bone scan for patients with newly diagnosed prostate cancer. METHODS: The clinical data of continual 95 patients with newly diagnosed prostate cancer was involved between January 2006 and December 2010. The relationship between age, PSA, Gleason scores, clinical stage and positive bone scans was respectively compared. RESULTS: The 33 patients (34.7%) with positive bone scans and 62 patients (65.3%) with negative bone scans. The mean age was (74±7) years and (76±7) years respectively in 2 groups respectively. PSA was (70.7±38.1) ng/ml and (28.4±27.2) ng/ml respectively, the difference was significant (t=-5.499, P=0.000). Clinical stage had positive correlation with positive bone scan, the OR value was 4.684. If the Gleason score>7, the sensitivity, specificity, positive predictive value and negative predictive value of positive bone scan was 64%, 63%, 48% and 77% respectively. If PSA>50 ng/ml, sensitivity, specificity, positive predictive value and negative predictive value was 67%, 86%, 71% and 83% respectively. If Clinical stage>T2, sensitivity, specificity, positive predictive value and negative predictive value was 82%, 81%, 69% and 89% respectively. CONCLUSIONS: For patients with PSA≤10 ng/ml or simultaneously PSA≤50 ng/ml and Gleason score≤7 and clinical stage≤T2, bone scan is not necessary. Patients with newly diagnosed prostate cancer and PSA>50 ng/ml or Gleason score>7 or clinical stage>T2 should undergo bone scan.

Total kinetic analysis reveals how combinatorial methylation patterns are established on lysines 27 and 36 of histone H3.

We have developed a targeted method to quantify all combinations of methylation on an H3 peptide containing lysines 27 and 36 (H3K27-K36). By using stable isotopes that separately label the histone backbone and its methylations, we tracked the rates of methylation and demethylation in myeloma cells expressing high vs. low levels of the methyltransferase MMSET/WHSC1/NSD2. Following quantification of 99 labeled H3K27-K36 methylation states across time, a kinetic model converged to yield 44 effective rate constants qualifying each methylation and demethylation step as a function of the methylation state on the neighboring lysine. We call this approach MS-based measurement and modeling of histone methylation kinetics (M4K). M4K revealed that, when dimethylation states are reached on H3K27 or H3K36, rates of further methylation on the other site are reduced as much as 100-fold. Overall, cells with high MMSET have as much as 33-fold increases in the effective rate constants for formation of H3K36 mono- and dimethylation. At H3K27, cells with high MMSET have elevated formation of K27me1, but even higher increases in the effective rate constants for its reversal by demethylation. These quantitative studies lay bare a bidirectional antagonism between H3K27 and H3K36 that controls the writing and erasing of these methylation marks. Additionally, the integrated kinetic model was used to correctly predict observed abundances of H3K27-K36 methylation states within 5% of that actually established in perturbed cells. Such predictive power for how histone methylations are established should have major value as this family of methyltransferases matures as drug targets.

Separation of variant methylated histone tails by differential ion mobility.

Differential ion mobility spectrometry (field asymmetric waveform ion mobility spectrometry (FAIMS)) is emerging as a broadly useful tool for separation of isomeric modified peptides with post-translational modifications (PTMs) attached to alternative residues. Such separations were anticipated to become more challenging for smaller PTMs and longer peptides. Here, we show that FAIMS can fully resolve localization variants involving a PTM as minuscule as methylation, even for larger peptides in the middle-down range.

Ion mobility separation of variant histone tails extending to the "middle-down" range.

Differential ion mobility spectrometry (FAIMS) can baseline-resolve multiple variants of post-translationally modified peptides extending to the 3-4 kDa range, which differ in the localization of a PTM as small as acetylation. Essentially orthogonal separations for different charge states expand the total peak capacity with the number of observed states that increases for longer polypeptides. This potentially enables resolving localization variants for yet larger peptides and even intact proteins.