Three novel oligosaccharides synthesized using Thermoanaerobacter brockii kojibiose phosphorylase

<p>Abstract</p> <p>Background</p> <p>Recently synthesized novel oligosaccharides have been produced primarily by hydrolases and glycosyltransferases, while phosphorylases have also been subject of few studies. Indeed, phosphorylases are expected to give good results via their reversible reaction. The purpose of this study was to synthesis other novel oligosaccharides using kojibiose phosphorylase.</p> <p>Results</p> <p>Three novel oligosaccharides were synthesized by glucosyltransfer from β-D-glucose 1-phosphate (β-D-G1P) to xylosylfructoside [<it>O</it>-α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside] using <it>Thermoanaerobacter brockii </it>kojibiose phosphorylase. These oligosaccharides were isolated using carbon-Celite column chromatography and preparative high performance liquid chromatography. Gas liquid chromatography analysis of methyl derivatives, MALDI-TOF MS and NMR measurements were used for structural characterisation. The ¹H and ¹³C NMR signals of each saccharide were assigned using 2D-NMR including COSY (correlated spectroscopy), HSQC (herteronuclear single quantum coherence), CH₂-selected E-HSQC (CH₂-selected Editing-HSQC), HSQC-TOCSY (HSQC-total correlation spectroscopy) and HMBC (heteronuclear multiple bond correlation).</p> <p>Conclusion</p> <p>The structure of three synthesized saccharides were determined, and these oligosaccharides have been identified as <it>O</it>-α-D-glucopyranosyl-(1→2)-<it>O</it>-α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside (saccharide <b>1</b>), <it>O</it>-α-D-glucopyranosyl-(1→2)-<it>O</it>-α-D-glucopyranosyl-(1→2)-<it>O</it>-α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside (saccharide <b>2</b>) and <it>O</it>-α-D-glucopyranosyl-(1→[2-<it>O</it>-α-D-glucopyranosyl-1]₂→2)-<it>O</it>-α-D-xylopyranosyl-(1→2)-β-D-fructofuranoside (saccharide <b>3</b>).</p

Bevacizumab increases the sensitivity of olaparib to homologous recombination-proficient ovarian cancer by suppressing CRY1 via PI3K/AKT pathway

PARP inhibitors have changed the management of advanced high-grade epithelial ovarian cancer (EOC), especially homologous recombinant (HR)-deficient advanced high-grade EOC. However, the effect of PARP inhibitors on HR-proficient (HRP) EOC is limited. Thus, new therapeutic strategy for HRP EOC is desired. In recent clinical study, the combination of PARP inhibitors with anti-angiogenic agents improved therapeutic efficacy, even in HRP cases. These data suggested that anti-angiogenic agents might potentiate the response to PARP inhibitors in EOC cells. Here, we demonstrated that anti-angiogenic agents, bevacizumab and cediranib, increased the sensitivity of olaparib in HRP EOC cells by suppressing HR activity. Most of the γ-H2AX foci were co-localized with RAD51 foci in control cells. However, most of the RAD51 were decreased in the bevacizumab-treated cells. RNA sequencing showed that bevacizumab decreased the expression of CRY1 under DNA damage stress. CRY1 is one of the transcriptional coregulators associated with circadian rhythm and has recently been reported to regulate the expression of genes required for HR in cancer cells. We found that the anti-angiogenic agents suppressed the increase of CRY1 expression by inhibiting VEGF/VEGFR/PI3K pathway. The suppression of CRY1 expression resulted in decrease of HR activity. In addition, CRY1 inhibition also sensitized EOC cells to olaparib. These data suggested that anti-angiogenic agents and CRY1 inhibitors will be the promising candidate in the combination therapy with PARP inhibitors in HR-proficient EOC

Thermoanaerobacter brockii Kojibiose Phosphorylaseによって合成された新規三および四糖の分離および同定

Novel tri- and tetra-saccharides were synthesized by glucosyltransfer from β-D-glucose 1-phosphate (β-D-G1P) to palatinose using Thermoanaerobacter brockii kojibiose phosphorylase. There saccharides were isolated using carbon-Celite column chromatography and preparative high performance liquid chromatography. Gas liquid chromatography analysis of methyl derivatives, MALDI-TOF MS and NMR measurements were used for structural confirmation of the saccharides. The ^1H and ^13C NMR signals of the saccharides were assigned using 2D-NMR including COSY, HSQC, HSQC-TOCSY and HMBC. These oligosaccharides were identified as 2^G-α-D-glucopyranosyl-palatinose; O-α-D-glucopyranosyl-(1→2)-O-α-D-glucopyranosyl-(1→6)-D-fructofuranose and 2^G(2-α-D-glucopyranosyl)_2-palatinose; O-α-D-glucopyranosyl-(1→2)-O-α-D-glucopyranosyl-(1→2)-O-α-D-glucopyranosyl-(1→6)-D-fructofuranose. パラチノースは抗う蝕性のようなさまざまな機能をもつことが知られている．しかしながら，パラチノースはゆっくりではあるが小腸で加水分解をうけるため，糖尿病のような疾患をもつ患者への使用は薦められない．さらに，この糖のような低分子のオリゴ糖は比較的高浸透圧になりやすいため生体にとってよくない影響を及ぼすことがある．本研究では，二糖であるパラチノースを用い，Thermoanaerobacter brockii kojibiose phosphorylaseのグルコシル転移作用を利用し，グルコース1リン酸とパラチノースから新規オリゴ糖を合成した．反応は糖1および糖2が効率よく生成した48時間で止めた (Fig. 1)．また，転移生成物である糖1は反応10時間で最大となった (Fig. 2)．活性炭-セライトカラムおよび調製用HPLCを用いて糖1および糖2を単離し，MALDI-TOF-MS分析およびメチル誘導体のガスクロマトグラフィー分析を行い構造の推定を行った (Fig. 3)．さらにCOSY，HSQC，HSQC-TOCSYおよびHMBC (Fig. 4) の各手法を用いた2次元NMR解析により糖1を2^G-α-D-glucopyranosyl-palatinose; O-α-D-glucopyranosyl-(1→2)-O-α-D-glucopyranosyl- (1→6)-D-fructofuranose，糖2を2^G(2-α-D-glucopyranosyl)_2-palatinose; O-α-D-glucopyranosyl-(1→2)-O-α-D-glucopyranosyl- (1→2)-O-α-D-glucopyranosyl-(1→6)-D-fructofuranoseと同定した (Table 1)．今後，これらの糖の栄養機能について明らかにする必要があ

Chemistry Central Journal Three novel oligosaccharides synthesized using Thermoanaerobacter brockii kojibiose phosphorylase

Abstract Background: Recently synthesized novel oligosaccharides have been produced primarily by hydrolases and glycosyltransferases, while phosphorylases have also been subject of few studies. Indeed, phosphorylases are expected to give good results via their reversible reaction. The purpose of this study was to synthesis other novel oligosaccharides using kojibiose phosphorylase

Boron Neutron Capture Therapy for Malignant Brain Tumors

Boron neutron capture therapy (BNCT) is a biochemically targeted radiotherapy based on the nuclear capture and fission reactions that occur when non-radioactive boron-10, which is a constituent of natural elemental boron, is irradiated with low energy thermal neutrons to yield high linear energy transfer alpha particles and recoiling lithium-7 nuclei. Therefore, BNCT enables the application of a high dose of particle radiation selectively to tumor cells in which boron-10 compound has been accumulated. We applied BNCT using nuclear reactors for 167 cases of malignant brain tumors, including recurrent malignant gliomas, newly diagnosed malignant gliomas, and recurrent high-grade meningiomas from January 2002 to May 2014. Here, we review the principle and history of BNCT. In addition, we introduce fluoride-18-labeled boronophenylalanine positron emission tomography and the clinical results of BNCT for the above-mentioned malignant brain tumors. Finally, we discuss the recent development of accelerators producing epithermal neutron beams. This development could provide an alternative to the current use of specially modified nuclear reactors as a neutron source, and could allow BNCT to be performed in a hospital setting