Tripartite motif-containing 25 facilitates immunosuppression and inhibits apoptosis of glioma via activating NF-κB.

As a crucial tumor type of the central nervous system, gliomas are characterized by a dismal prognosis. Tripartite motif-containing 25 (TRIM25), an essential E3 ubiquitin ligase, participates in various biological processes. This study sought to demonstrate its functional role in gliomas. Data obtained from publicly available databases - including The Cancer Genome Atlas (TCGA), the Chinese Glioma Genome Atlas (CGGA), and the Repository for Molecular Brain Neoplasia Data (REMBRANDT) - were employed. TRIM25 expression pattern and its association with different clinical characteristics were analyzed. Kaplan-Meier analysis was utilized to compare different TRIM25 expressions with glioma patients' survival. Subsequently, we performed bioinformatic analyses to investigate the biological functions of TRIM25, which were further validated by in vitro experiments, CIBERSORT algorithm, and ESTIMATE evaluation. TRIM25 expression was upregulated in glioma patients and can predict an unfavorable prognosis. Bioinformatic results indicated the involvement of TRIM25 in apoptosis and immune regulation. TRIM25 was associated with programmed death-ligand 1 (PD-L1) related and macrophage-induced immune suppression in gliomas. Meanwhile, silencing TRIM25 promoted apoptosis in glioma cells, which is attributed to its regulation of NF-κB. Therefore, TRIM25 contributed to the glioma malignant progression and suppressive immune microenvironments via NF-κB activation, which may play a therapeutic role in gliomas.

Cascade synthesis of uridine-5'-diphosphate glucuronic acid by coupling multiple whole cells expressing hyperthermophilic enzymes.

BACKGROUND: Enzymatic glycan synthesis has leapt forward in recent years and a number of glucuronosyltransferase (EC 2.4.1.17) have been identified and prepared, which provides a guide to an efficient approach to prepare glycans containing glucuronic acid (GlcA) residues. The uridine 5'-diphosphate (UDP) activated form, UDP-GlcA, is the monosaccharide donor for these glucuronidation reactions. RESULTS: To produce UDP-GlcA in a cost-effective way, an efficient three-step cascade route was developed using whole cells expressing hyperthermophilic enzymes to afford UDP-GlcA from starch. By coupling a coenzyme regeneration system with an appropriate expression level with UDP-glucose 6-dehydrogenase in a single strain, the cells were able to meet NAD+ requirements. Without addition of exogenous NAD+, the reaction produced 1.3 g L-1 UDP-GlcA, representing 100% and 46% conversion of UDP-Glc and UTP respectively. Finally, an anion exchange chromatography purification method was developed. UDP-GlcA was successfully obtained from the cascade system. The yield of UDP-GlcA during purification was about 92.0%. CONCLUSIONS: This work built a de novo hyperthermophilic biosynthetic cascade into E. coli host cells, with the cells able to meet NAD+ cofactor requirements and act as microbial factories for UDP-GlcA synthesis, which opens a door to large-scale production of cheaper UDP-GlcA.

Inertial-Range Reconnection in Magnetohydrodynamic Turbulence and in the Solar Wind.

In situ spacecraft data on the solar wind show events identified as magnetic reconnection with wide outflows and extended "X lines," 10(3)-10(4) times ion scales. To understand the role of turbulence at these scales, we make a case study of an inertial-range reconnection event in a magnetohydrodynamic simulation. We observe stochastic wandering of field lines in space, breakdown of standard magnetic flux freezing due to Richardson dispersion, and a broadened reconnection zone containing many current sheets. The coarse-grain magnetic geometry is like large-scale reconnection in the solar wind, however, with a hyperbolic flux tube or apparent X line extending over integral length scales.

Antitumor effects of a novel histone deacetylase inhibitor NK-HDAC-1 on breast cancer.

Histone deacetylases (HDACs) are overexpressed in various types of primary human cancer and have become attractive targets for cancer therapy. We designed and synthesized a series of new class of HDAC inhibitors (HDACi). Among these, S-(E)-3-(1-(1-(benzo[d]oxazol-2-yl)-2-methylpropyl)-1H-1,2,3-triazol-4-yl)-N-hydroxyacrylamide (NK-HDAC-1) showed potent antitumor activity. In the present study, we examined the antitumor effects of NK-HDAC-1 on breast cancer in vitro and in vivo. The inhibitory effects of NK-HDAC-1 on HDAC enzyme activity and cell growth were more potent compared to suberoylanilide hydroxamic acid (SAHA). NK-HDAC-1 caused G1 cell cycle arrest at concentrations below 0.2 µM and G2/M arrest at concentrations above 0.4 µM through p21 upregulation and cyclin D1 downregulation. NK-HADC-1 induced hyperacetylation of histone H3 and H4 around the promoter region of p21. NK-HDAC-1 promoted apoptosis in MDA-MB-231 breast cancer cells by activating both the intrinsic and the extrinsic pathway NK-HDAC-1 at doses of 3, 10 and 30 mg/kg reduced the tumor volume in MDA-MB-231 xenografts by 25.9, 48.8 and 63.6%, respectively. The results suggested that NK-HDAC-1 may be a promising therapeutic candidate in treating human breast cancer.

Discovery and extensive in vitro evaluations of NK-HDAC-1: a chiral histone deacetylase inhibitor as a promising lead.

Herein, further SAR studies of lead compound NSC746457 (Shen, J.; Woodward, R.; Kedenburg, J. P.; Liu, X. W.; Chen, M.; Fang, L. Y.; Sun; D. X.; Wang. P. G. J. Med. Chem. 2008, 51, 7417-7427) were performed, including the replacement of the trans-styryl moiety with a 2-substituted benzo-hetero aromatic ring and the introduction of a substituent onto the central methylene carbon. A promising chiral lead, S-(E)-3-(1-(1-(benzo[d]oxazol-2-yl)-2-methylpropyl)-1H-1,2,3-triazol-4-yl)-N-hydroxyacrylamide (12, NK-HDAC-1), was discovered and showed about 1 order of magnitude more potency than SAHA in both enzymatic and cellular assays. For the in vitro safety tests, NK-HDAC-1 was far less toxic to nontransformed cells than tumor cells and showed no significant inhibition activity against CYP-3A4. The pharmaceutical properties (LogD, solubility, liver micrsomal stability (t1/2), plasma stability (t1/2), and apparent permeability) strongly suggested that NK-HDAC-1 might be superior to SAHA in bioavailability and in vivo half-life.

The histone deacetylase inhibitor suberoylanilide hydroxamic acid induces growth inhibition and enhances taxol-induced cell death in breast cancer.

PURPOSE: The histone deacetylase inhibitor (HDACi) suberoylanilide hydroxamic acid (SAHA) enhances taxol-induced antitumor effects against some human cancer cells. The aim of this study is to investigate whether SAHA can enhance taxol-induced cell death against human breast cancer cells and to illustrate the mechanism in detail. METHODS: A panel of eight human breast cancer cell lines and an immortalized human breast epithelial cell line were used to determine the inhibitory effects of SAHA, taxol, or their combination by MTT assay. The effects of SAHA with or without taxol on cell cycle distributions, apoptosis, and protein expressions were also examined. The inhibitory effects on tumor growth were characterized in vivo in BALB/c nude mice bearing a breast cancer xenograft model. RESULTS: Taxol-resistant and multi-resistant breast cancer cells were as sensitive to SAHA as taxol-sensitive breast cancer cells. A dose-dependent synergistic growth inhibition was found in all the tested breast cancer cell lines treated with the SAHA/taxol combinations. The synergetic effect was also observed in the in vivo xenograft tumor model. The cell cycle analysis and apoptosis assay showed that the synergistic effects resulted from enhanced G2/M arrest and apoptosis. CONCLUSIONS: SAHA increased the anti-tumor effects of taxol in breast cancer in vitro and in vivo. The combination of SAHA and taxol may have therapeutic potential in the treatment of breast cancer.

MCM7 interacts with androgen receptor.

MCM7 is a critical component of the DNA replication licensing complex that controls DNA replication in both yeast and Xenopus. Our previous studies have indicated that MCM7 is both amplified and overexpressed in metastatic prostate cancer. In this study, we found that MCM7 interacts with the androgen receptor (AR) with high affinity both in vitro and in vivo. We identified the AR-binding motif for MCM7, comprised of amino acids 221 to 248, and the MCM7-binding motif for the AR, comprised of amino acids 426 to 475. AR stimulation with high doses of the synthetic androgen R1881 led to a decrease in MCM7 binding to genomic DNA, a reduction of DNA synthesis, decreases in the number of cells progressing through S phase and cell proliferation, whereas low doses produced an increase in the DNA licensing activity of MCM7 and higher levels of cell proliferation. In addition, the MCM7/AR interaction down-regulated MCM7 expression. The gene transcription or repressor activity of AR is dependent on its interaction with MCM7 because either a mutant AR defective in its interaction with MCM7 or a MCM7 knockdown primarily eliminated AR effects on gene expression. Thus, this study reveals a novel mechanism by which AR and MCM7 facilitate each other's function, suggesting that AR-independent activation of MCM7 may be a mechanism by which prostate cancers bypass therapeutically induced AR blockade.

[Chemosensitivity of mdr1 gene overexpressed multidrug resistant cancer cells to lidamycin].

AIM: To investigate the chemosensitivity to lidamycin (C-1027) in mdr1 gene overexpressing cancer cell lines established by drug induction and by gene-transfection. METHODS: DNA was cloned by RT-PCR and then eukaryotic expressing recombinant plasmid pcDNA3. 1/mdrl was constructed. Using Lipofectamine 2000, a strain of stably transfected human hepatoma cancer cells, HepG2/mdrl, was obtained. The mdr1 mRNA level, P-glycoprotein (P-gp) level and the activity of P-gp to extrude drugs in cancer cells were determined by RT-PCR, immunofluorescence analysis and rhodamine 123 efflux assay. The chemosensitivity of cancer cells with low or high mdr1 expression to lidamycin and other antitumor drugs was tested by MTT assay. RESULTS: The mdr1 mRNA and P-gp levels in KBv200, MCF-7/ADR, and stably transfected HepG2/mdr1 cells were much higher than that in respective parent KB, MCF-7 and HepG2 cells. The IC50 values of lidamycin for KBv200, MCF-7/ADR and HepG2/mdrl cells were (0.24 +/- 0.20) nmol x L(-1), (0.028 +/- 0.011) nmol x L(-1), and (0.020 +/- 0.011) nmol x L(-1), respectively. Compared with parental cells, the values of resistant fold for KBv200, MCF-7/ADR and HepG2/mdr1 cells to lidamycin were 6.8, 1.6 and 1.3 fold; to adriamycin were 37.2, 181.3 and 8.8 fold; to taxol were 336.8, 49.2 and 40.3 fold, respectively. CONCLUSION: Lidamycin is highly active to multidrug resistant cancer cells. The chemosensitivity of those resistant cancer cells to lidamycin is approximately at the similar level as that of parent cancer cells.

[A study on biomarkers of styrene].

OBJECTIVE: To study the biomarkers of styrene and to provide theoretical basis for bio-monitoring of styrene. METHODS: Urinary mandalic acid (MA), phenylglyoxalic acid (PGA) and mercapturic acid (MUA) of styrene were examined by high performance liquid chromatography (HPLC). RESULTS: The correlation regression equations between exposure dose and MA, PGA and MUA level in morning urinary samples were: y = 2.58x + 70.82; y = 1.66x + 37.42; y = 0.05x + 0.55 respectively. The correlation regression equations between exposure dose and MA, PGA and MUA level in post-shift urinary samples were: y = 1.85x + 89.02; y = 1.33x + 4.32; y = 0.04x + 0.68 respectively. All showed close dose-response relationship. CONCLUSIONS: The level of MA, PGA and MUA in morning or post-shift urinary samples may be used as bio-monitoring indexes of styrene.