Forkhead box protein FOXK1 disrupts the circadian rhythm to promote breast tumorigenesis in response to insulin resistance.

The dysregulation of circadian rhythm oscillation is a prominent feature of various solid tumors. Thus, clarifying the molecular mechanisms that maintain the circadian clock is important. In the present study, we revealed that the transcription factor forkhead box FOXK1 functions as an oncogene in breast cancer. We showed that FOXK1 recruits multiple transcription corepressor complexes, including NCoR/SMRT, SIN3A, NuRD, and REST/CoREST. Among them, the FOXK1/NCoR/SIN3A complex transcriptionally regulates a cohort of genes, including CLOCK, PER2, and CRY2, that are critically involved in the circadian rhythm. The complex promoted the proliferation of breast cancer cells by disturbing the circadian rhythm oscillation. Notably, the nuclear expression of FOXK1 was positively correlated with tumor grade. Insulin resistance gradually became more severe with tumor progression and was accompanied by the increased expression of OGT, which caused the nuclear translocation and increased expression of FOXK1. Additionally, we found that metformin downregulates FOXK1 and exports it from the nucleus, while HDAC inhibitors (HDACi) inhibit the FOXK1-related enzymatic activity. Combined treatment enhanced the expression of circadian clock genes through the regulation of FOXK1, thereby exerting an antitumor effect, indicating that highly nuclear FOXK1-expressing breast cancers are potential candidates for the combined application of metformin and HDACi.

One-pot Twostep Chemobiocatalytic Synthesis of a Furan Amino Acid from 5-Hydroxymethylfurfural.

Recently, catalytic valorization of biomass-derived furans has received growing interest. 5-Aminomethyl-2-furancarboxylic acid (AMFC), a furan amino acid, holds great promise in the aeras of polymer and pharmaceutical, but its synthesis remains limited. In this work, we report a chemobiocatalytic route toward AMFC by combining laccase-TEMPO system and recombinant Escherichia coli (named E. coli_TAF) harboring ω-transaminase (TA), L-alanine dehydrogenase (L-AlaDH) and formate dehydrogenase (FDH), starting from 5-hydroxymethylfurfural (HMF). In the cascade, HMF is oxidized into 5-formyl-2-furancarboxylic acid (FFCA) by laccase-TEMPO system, and then the resulting intermediate is converted into AMFC by E. coli_TAF via transamination with cheap ammonium formate instead of costly organic amine donors, theoretically generating H2O and CO2 as by-products. The tandem process was run in a one-pot twostep manner, affording AMFC with approximately 81 % yield, together with 10 % 2,5-furandicarboxylic acid (FDCA) as by-product. In addition, the scale-up production of AMFC was demonstrated, with 0.41 g/L h productivity and 8.6 g/L titer. This work may pave the way for green manufacturing of the furan-containing amino acid.

Influence of calcium chloride impregnation on the thermal and high-temperature carbonization properties of bamboo fiber.

In this study, bamboo fiber was pretreated with calcium chloride (CaCl2) solution by using an ultrasonic method, and then heat-treated at 250°C and carbonized at 1000°C. The effect of impregnation with CaCl2 on the thermal and chemical properties and morphology of bamboo fiber was determined using thermogravimetric and differential thermogravimetric analyses, in situ Fourier transform infrared spectroscopy, and scanning electron microscopy. The pore structure of the carbonized bamboo fiber was investigated. The results revealed that bamboo fiber pretreated with 5% CaCl2 (BFCa5) showed a downward shift in the temperature of the maximum rate of weight loss253°C and increase in char residue to 31.89%. BFCa5 was expected to undergo dehydration under the combined effect of oxygen-rich atmosphere and CaCl2 catalysis from 210°C, and cellulose decomposition would be remarkable at 250°C. Pretreatment with 5% CaCl2 promoted the formation of porous structure of the carbonized fiber, which exhibited a typical Type-IV isotherm, with the Brunauer-Emmett-Teller specific surface area of 331.32 m2/g and Barrett-Joyner-Halenda adsorption average pore diameter of 13.6440 nm. Thus, CaCl2 was found to be an effective catalyst for the pyrolysis of bamboo fiber, facilitating the formation of porous carbonized fiber.

PPARα Regulates the Proliferation of Human Glioma Cells through miR-214 and E2F2.

Peroxisome proliferator-activated receptor α (PPARα) is a member of the nuclear hormone receptor superfamily and functions as a transcription factor. Previous work showed that PPARα plays multiple roles in lipid metabolism in tissues such as cardiac and skeletal muscle, liver, and adipose tissue. Recent studies have discovered additional roles for PPARα in cell proliferation and metabolism, as well as tumor progression. PPARα is aberrantly expressed in various cancers, and activated PPARα inhibits the proliferation of some tumor cells. However, there have been no studies of PPARα in human gliomas. Here, we show that PPARα is expressed at lower levels in anaplastic gliomas and glioblastoma multiforme (GBM) tissue compared with low-grade gliomas tissue, and low expression is associated with poor patient prognosis. PPARα activates transcription of dynamin-3 opposite strand (DNMO3os), which encodes a cluster of miR-214, miR-199a-3p, and miR-199a-5p microRNAs. Of these, miR-214 is transcribed at particularly high levels. PPARα-induced miR-214 expression causes downregulation of its target E2F2. Finally, miR-214 overexpression inhibits glioma cell growth in vitro and in vivo by inducing cell cycle arrest in G0/G1. Collectively, these data uncover a novel role for a PPARα-miR-214-E2F2 pathway in controlling glioma cell proliferation.

miR­218 inhibits the proliferation of human glioma cells through downregulation of Yin Yang 1.

Malignant glioma is the most common cancer type of the nervous system and the mechanisms driving the occurrence and development remain unclear, preventing effective treatment of this disease. Therefore, novel and efficient therapies for glioma are required. MicroRNAs (miRNAs) are small non­coding RNAs that act as oncogenes or tumor suppressors in human cancer. In the present study, it was confirmed that Yin Yang­1 (YY1), a transcription factor that is part of the polycomb group protein (PcG) family, is a direct target of miR­218 in human glioma cells. It was demonstrated that YY1 promoted glioma cell proliferation and miR­218 could inhibit glioma cell proliferation by targeting YY1, and indirectly reduced the degradation of p53. Together the results indicate that miR­218 functions as a tumor suppressor in human glioma and suggest that overexpression of miR­218 may be a potential strategy for the treatment of human glioma in the future.

[Over-expression of miR-497 promotes the proliferation of U87 glioma cells by targeting neuregulin receptor degradation protein 1].

Objective To investigate the effect of miR-497 over-expression on the proliferation of U87 human glioma cells. Methods We packaged both pGLV3/H1-NC lentivirus as a negative control group and pGLV3/H1-miR-497 lentivirus as an experimental group, and then constructed U87-NC and U87-miR-497 cell lines, respectively. The relationship between miR-497 and neuregulin receptor degradation protein 1 (Nrdp1) was analyzed by luciferase reporter assay in U87 cells; cell colony formation assay was used to detect cell proliferation and flow cytometry to detect cell cycle; the expressions of Nrdp1, AKT and phosphorylated AKT (p-AKT) were determined by Western blotting. Results We successfully packaged pGLV3/H1-NC and pGLV3/H1-miR-497 lentivirus, and obtained stable U87-NC and U87-miR-497 cell lines. When miR-497 was over-expressed in U87 cells, the cell colony formation ability was enhanced compared with the control group U87-NC. The luciferase reporter assay confirmed that miR-497 targeted Nrdp1 in U87 cells. In the stable infected cells, the level of Nrdp1 protein decreased and p-AKT protein increased, while the AKT protein did not change significantly after over-expression of miR-497. Conclusion Over-expression of miR-497 promotes the proliferation of glioma cells U87 by targeting Nrdp1.

Glioma stem cells involved in tumor tissue remodeling in a xenograft model.

OBJECT: Although tissue remodeling plays a crucial role in the tumorigenesis and progression of human gliomas, its mechanisms remain largely uncertain. In the current study, the authors investigated the potential role of human glioma stem cells (hGSCs) in the tissue remodeling of gliomas. METHODS: Transgenic nude mice with ubiquitous green fluorescent protein (GFP) expression were obtained by crossing nontransgenic NC athymic nude mice with the GFP transgenic C57BL/6J mice. As a result, GFP was expressed in essentially all tissues in the offspring. Human glioma stem cells were then orthotopically implanted into the GFP nude mice in an effort to assess the hGSC-host brain interactions and thereby elucidate the roles of tissue remodeling during tumorigenesis and progression of human gliomas. RESULTS: All of the essential tissues in the GFP transgenic nude mice, including the brain, fluoresced green under an excitation light; therefore, tumor remodeling by hGSCs can be unambiguously distinguished from a bright green background composed of adjacent host GFP-expressing components. This technique enabled the authors to address the following concerns: 1) hGSCs were involved in the invasiveness of gliomas and adjacent stroma degradation of the host. 2) An in vivo study demonstrated that cell fusion occurred between hGSCs and host cells. 3) Vasculogenic mimicry--the formation of patterned, tubular networks of vascular channels by transdifferentiated hGSCs--could be observed. 4) Differentiation mimicry--namely, the differentiation direction of hGSCs bearing multidifferentiation potentials--seemed to be decided by the local host cellular microenviroment. CONCLUSIONS: The results of this study indicated that the GFP transgenic nude mice model with GFP expression in essentially all tissues could be obtained by crossing nontransgenic athymic nude mice with transgenic GFP mice. This model should greatly expand our knowledge of glioma-host interactions. The data indicated that hGSCs might play a decisive role in tissue remodeling of gliomas as well.

[Transplantation of human glioma stem cells in nude mice with green fluorescent protein expression].

OBJECTIVES: To investigate the possibility of transplantation of human glioma stem cells (HGSCs) in nude mice stably expressing green fluorescent protein (GFP) so as to clearly identify the incubated HGSCs from the host tissues. METHODS: Transgenic C57BL/6J mice expressing GFP was crossed with nude mice of the line NC, then hairless male nude mice expressing GFP were crossed with hairy female pubescent mice to obtain nude mice with GFP expression the expression of GFP in the skin and organs of these nude mice were evaluated by naked eyes, and immunohistochemical and immunofluorescence assays. HGSCs were transplanted orthotopically into the caudate nuclei of nude mice expressing GFP. Immunohistochemistry was used to observe the transplanted tumor. RESULTS: The structures rich in adipose tissue of the 8th generation nude mice were dark green and the other organs were light green. However, green fluorescence was emitted from all tissues under fluorescence microscopy. Confocal fluorescence microscopy showed that the tumor cells were stained red, distinguished from the host cells distinctly in the brains bearing tumor transplanted orthotopically. CONCLUSION: Nude mice expressing GFP can be obtained by crossing the transgenic mice bearing naive immunity with nude mice. Orthotopic transplantation of HGSCs may be used in the investigation of tumor tissue reconstitution because of the easy identification between the transplantation tumor and host tissue.

Synthesis of divalent beta-(1-->6)-branched (1-->3)-glucohexaose and trivalent beta-(1-->6)-branched (1-->3)-glucotriose.

Hexaose, beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-alpha-D-Glcp-(1-->3)-beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-beta-D-Glcp, based dimers were synthesized by twofold glycosidation of the hexaosyl trichloroacetimidate with hexylene 1,6-diol, diethylene glycol and triethylene glycol, respectively. Meanwhile, a triose, beta-1D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-beta-D-Glcp, based trimer was obtained by glycosidation of the triosyl trichloroacetimidate with a glycerol-derived triol scaffold.

Synthesis of mannose-containing analogues of (1-->6)-branched (1-->3)-glucohexaose.

Coupling of the trisaccharide acceptor 2,4,6-tri-O-acetyl-beta-D-glucopyranosyl-(1-->3)-[2,3,4,6-tetra-O-benzoyl-beta-D-glucopyranosyl-(1-->6)]-5-O-acetyl-1,2-O-isopropylidene-alpha-D-glucofuranose (2) with the trisaccharide donor 2,3,4,6-tetra-O-benzoyl-alpha-D-annopyranosyl-(1-->3)-[2,3,4,6-tetra-O-benzoyl-beta-D-glucopyranosyl-(1-->6)]-2,4-di-O-acetyl-alpha-D-glucopyranosyl trichloroacetimidate (1) gave an alpha-linked hexasaccharide 3, while coupling of 2 with the trisaccharide donor 2,3,4,6-tetra-O-benzoyl-alpha-D-mannopyranosyl-(1-->3)-[2,3,4,6-tetra-O-benzoyl-alpha-D-mannopyranosyl-(1-->6)]-2,4-di-O-acetyl-alpha-D-glucopyranosyl trichloroacetimidate (7) produced alpha- 8 and beta-linked 12 hexasaccharides in a ratio of 3:2. Deprotection of 3, 8, and 12 afforded the analogues of the immunomodulator beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-alpha-D-Glcp-(1-->3)-beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-D-Glcp (A).

Synthesis of beta-(1-->6)-branched (1-->3)-glucododecaose and -glucopentadecaose with alternate beta- and alpha-bonds in the backbone.

Beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-alpha-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-alpha-D-Glcp-(1-->3)](2-3)-beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-beta-D-Glcp were synthesized as their methoxyphenyl glycosides in a concise way with a trisaccharide as the building block.

Synthesis of mannose-containing analogues of (1-->6)-branched (1-->3)-glucohexaose (I).

alpha-D-Manp-(1-->3)-[alpha-D-Manp-(1-->6)]-alpha-D-Glcp-(1-->3)-beta-D-Glcp-(1-->3)-[alpha-D-Manp-(1-->6)]-D-Glcp and alpha-D-Manp-(1-->3)-[beta-D-Glcp-(1-->6)]-alpha-D-Glcp-(1-->3)-beta-D-Glcp-(1-->3)[-alpha-D-Manp-(1-->6)]-D-Glcp were synthesized in a regio- and stereoselective way as the mannose-containing analogues of the immunomodulating beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-alpha-D-Glcp-(1-->3)-beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-D-Glcp.