Low Quality of Warfarin Therapy is Associated With Female Gender but Not With Polypharmacy in Patients With Atrial Fibrillation.

Background: We examined the impact of polypharmacy on the quality of the anticoagulation therapy in patients with atrial fibrillation. We also examined the factors that affect the stability of warfarin therapy. Methods and Results: This retrospective study was conducted using data from 157 consecutive outpatients with atrial fibrillation in a single tertiary referral hospital. Patients who were prescribed warfarin continuously and for whom PT-INR was examined at least three times in a year were included in this study. We examined the quality of warfarin therapy using time in the therapeutic INR range (TTR), percentage of PT-INR determinations in range (PINRR), and the coefficient variation (CV) of PT-INR. We found that the number of prescribed medicines was significantly associated with high BMI and low eGFR, but not with TTR, PINRR, and the coefficient variation of PT-INR in patients with atrial fibrillation. We also found that female gender was independently associated with low PINRR in this study population. Conclusion: Polypharmacy did not deteriorate the quality of warfarin therapy in patients with atrial fibrillation treated in the tertiary referral hospital. Female gender was an independent predictor of the low quality of warfarin therapy.

Polypharmacy Is Associated With Accelerated Deterioration of Renal Function in Cardiovascular Outpatients.

BACKGROUND: Polypharmacy is associated with poor prognosis of patients with various diseases. However, it has not been precisely addressed how polypharmacy affects the clinical characteristics of the cardiovascular outpatients. The aim of this study is to search for the clinical characteristics related to the number of prescribed drugs in the cardiovascular outpatients. Also, we examine whether the number of the prescribed drugs affects the worsening of renal function. METHODS: This retrospective study was conducted using the data of 259 continuous cardiovascular outpatients who were examined complete blood count (CBC) and serum creatinine. RESULTS: In the univariate analysis, the number of prescribed drugs were associated with the number of cardiovascular diseases or their risk factors, age, white blood cells, platelet, body mass index, anemia, and chronic kidney disease stage 3b or higher. In the multivariable analysis, independent variables that significantly correlated with the number of prescribed drugs were the number of cardiovascular diseases or their risk factors, anemia, and chronic kidney disease stage 3b or higher. Among 259 patients, 208 patients received follow-up examination of serum creatinine. The number of prescribed drugs was the only factor that was associated with accelerated deterioration of renal function. CONCLUSIONS: Polypharmacy is associated not only with poor renal function but with accelerated deterioration of renal function. Polypharmacy may be causally related with renal dysfunction.

Discovery and characterization of a small-molecule enteropeptidase inhibitor, SCO-792.

Enteropeptidase, localized into the duodenum brush border, is a key enzyme catalyzing the conversion of pancreatic trypsinogen proenzyme to active trypsin, thereby regulating protein digestion and energy homeostasis. We report the discovery and pharmacological profiles of SCO-792, a novel inhibitor of enteropeptidase. A screen employing fluorescence resonance energy transfer was performed to identify enteropeptidase inhibitors. Inhibitory profiles were determined by in vitro assays. To evaluate the in vivo inhibitory effect on protein digestion, an oral protein challenge test was performed in rats. Our screen identified a series of enteropeptidase inhibitors, and compound optimization resulted in identification of SCO-792, which inhibited enteropeptidase activity in vitro, with IC 50 values of 4.6 and 5.4 nmol/L in rats and humans, respectively. In vitro inhibition of enteropeptidase by SCO-792 was potentiated by increased incubation time, and the calculated Kinact/KI was 82 000/mol/L s. An in vitro dissociation assay showed that SCO-792 had a dissociation half-life of almost 14 hour, with a calculated koff rate of 0.047/hour, which suggested that SCO-792 is a reversible enteropeptidase inhibitor. In normal rats, a ≤4 hour prior oral dose of SCO-792 effectively inhibited plasma elevation of branched-chain amino acids in an oral protein challenge test, which indicated that SCO-792 effectively inhibited protein digestion in vivo. In conclusion, our new screen system identified SCO-792 as a potent and reversible inhibitor against enteropeptidase. SCO-792 slowly dissociated from enteropeptidase in vitro and inhibited protein digestion in vivo. Further study using SCO-792 could reveal the effects of inhibiting enteropeptidase on biological actions.

Weyl Invariance of String Theories in Generalized Supergravity Backgrounds.

We revisit Weyl invariance string theories in generalized supergravity backgrounds. A possible counterterm was constructed in a work by Sakamoto, Sakatani, and Yoshida, but it seems to be a point of controversy in some literatures whether or not it is nonlocal. To settle down this issue, we show that the counterterm may be local and exactly cancels out the one-loop trace anomaly in generalized supergravity backgrounds.

Differential effects of selective agonists of neuromedin U1 and U2 receptors in obese and diabetic mice.

BACKGROUND AND PURPOSE: Neuromedin U (NmU) may be a novel target for obesity treatment owing to its anorectic and energy expenditure enhancing effects. Although two receptors, NMU1 and NMU2, are both responsible for the NmU-mediated anti-obesity effects, the receptor agonist with the most appropriate profiles for treating obesity and diabetes in terms of efficacy and safety is as yet unknown. Thus, we developed and evaluated novel NMU1/2 receptor-selective agonists. EXPERIMENTAL APPROACH: Efficacy and safety were assessed in mice with diet-induced obesity (DIO) and those with leptin-deficient diabetes (ob/ob) through repeated peripheral administration of selective agonists to NMU1 (NMU-6102) and NMU2 (NMU-2084), along with non-selective NMU1/2 agonists (NMU-0002 and NMU-6014). We also performed immunohistochemistry for c-Fos protein expression in the brain to probe their mechanisms of action. KEY RESULTS: Although both non-selective NMU1/2 agonists and the NMU2-selective agonist had high efficacy compared with the NMU1-selective agonist, only the NMU2-selective agonist led to relatively low adverse effects, such as diarrhoea, in DIO mice. However, the non-selective NMU1/2 agonist and the NMU1-selective agonist, but not the NMU2-selective agonist, were effective in diabetic ob/ob mice. Mechanistically, NMU2-selective agonists preferentially activate pro-opiomelanocortin neurons in the hypothalamic arcuate nucleus but not in the paraventricular nucleus. CONCLUSIONS AND IMPLICATIONS: These results suggest that an NMU2 receptor-selective agonist may be a well-balanced drug for the treatment of obesity and that an NMU1 receptor-selective agonist may also be beneficial for treating obesity and diabetes once its side effects are minimized.

Discovery of a novel B-cell lymphoma 6 (BCL6)-corepressor interaction inhibitor by utilizing structure-based drug design.

B-cell lymphoma 6 (BCL6) is a transcriptional repressor that can form complexes with corepressors via protein-protein interactions (PPIs). The complexes of BCL6 and corepressors play an important role in the formation of germinal centers (GCs), and differentiation and proliferation of lymphocytes. Therefore, BCL6-corepressor interaction inhibitors would be drug candidates for managing autoimmune diseases and cancer. Starting from high-throughput screening hits 1a and 2a, we identified a novel BCL6-corepressor interaction inhibitor 8c (cell-free enzyme-linked immunosorbent assay [ELISA] IC50=0.10µM, cell-based mammalian two-hybrid [M2H] assay IC50=0.72µM) by utilizing structure-based drug design (SBDD) based on an X-ray crystal structure of 1a bound to BCL6. Compound 8c also showed a good pharmacokinetic profile, which was acceptable for both in vitro and in vivo studies.

Crystal Structure of a Human K-Ras G12D Mutant in Complex with GDP and the Cyclic Inhibitory Peptide KRpep-2d.

The Ras proteins play roles in cell differentiation, proliferation, and survival. Aberrant signaling through Ras-mediated pathways in tumor cells occurs as a result of several types of mutational damage, which most frequently affects the amino acids G12, G13, and Q61. Recently, KRpep-2d was identified as a K-Ras(G12D) selective inhibitory peptide against the G12D mutant of K-Ras, which is a key member of the Ras protein family and an attractive cancer therapeutic target. In this study, the crystal structure of the human K-Ras(G12D) mutant was determined in complex with GDP and KRpep-2d at 1.25 Å resolution. This structure revealed that the peptide binds near Switch II and allosterically blocks protein-protein interactions with the guanine nucleotide exchange factor. This discovery of a unique binding pocket provides valuable information that will facilitate the design of direct Ras inhibitors.

Identification of cytidine-5-triphosphate synthase1-selective inhibitory peptide from random peptide library displayed on T7 phage.

Cytidine triphosphate synthase 1 (CTPS1) is an enzyme expressed in activated lymphocytes that catalyzes the conversion of uridine triphosphate (UTP) to cytidine triphosphate (CTP) with ATP-dependent amination, using either L-glutamine or ammonia as the nitrogen source. Since CTP plays an important role in DNA/RNA synthesis, phospholipid synthesis, and protein sialyation, CTPS1-inhibition is expected to control lymphocyte proliferation and size expansion in inflammatory diseases. In contrast, CTPS2, an isozyme of CTPS1 possessing 74% amino acid sequence homology, is expressed in normal lymphocytes. Thus, CTPS1-selective inhibition is important to avoid undesirable side effects. Here, we report the discovery of CTpep-3: Ac-FRLGLLKAFRRLF-OH from random peptide libraries displayed on T7 phage, which exhibited CTPS1-selective binding with a KD value of 210nM in SPR analysis and CTPS1-selective inhibition with an IC50 value of 110nM in the enzyme assay. Furthermore, two fundamentally different approaches, enzyme inhibition assay and HDX-MS, provided the same conclusion that CTpep-3 acts by binding to the amidoligase (ALase) domain on CTPS1. To our knowledge, CTpep-3 is the first CTPS1-selective inhibitor.

Discovery of a Kelch-like ECH-associated protein 1-inhibitory tetrapeptide and its structural characterization.

Keap1 constitutively binds to the transcription factor Nrf2 to promote its degradation, resulting in negative modulation of genes involved in cellular protection against oxidative stress. Keap1 is increasingly recognized as an attractive target for treating diseases involving oxidative stress, including cancer, atherosclerosis, diabetes, arthritis, and neurodegeneration. We used phage-display peptide screening to identify a tetrapeptide showing moderate binding affinity, which inhibits the interaction between Nrf2 and Keap1. The tetrapeptide does not include an ETGE motif, which is a commonly found consensus sequence in known peptidic inhibitors. In addition to affinity parameters, IC50, KD, and thermodynamic parameters, the crystal structure of the complex was determined to elucidate the binding conformation. The binding interactions resemble those of known small-molecule inhibitors as opposed to those of substrates and peptidic inhibitors. Although the tetrapeptide's affinity is not very high, our results may help facilitate the designing of small-molecule inhibitors during lead generation in drug discovery.

K-Ras(G12D)-selective inhibitory peptides generated by random peptide T7 phage display technology.

Amino-acid mutations of Gly12 (e.g. G12D, G12V, G12C) of V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (K-Ras), the most promising drug target in cancer therapy, are major growth drivers in various cancers. Although over 30 years have passed since the discovery of these mutations in most cancer patients, effective mutated K-Ras inhibitors have not been marketed. Here, we report novel and selective inhibitory peptides to K-Ras(G12D). We screened random peptide libraries displayed on T7 phage against purified recombinant K-Ras(G12D), with thorough subtraction of phages bound to wild-type K-Ras, and obtained KRpep-2 (Ac-RRCPLYISYDPVCRR-NH2) as a consensus sequence. KRpep-2 showed more than 10-fold binding- and inhibition-selectivity to K-Ras(G12D), both in SPR analysis and GDP/GTP exchange enzyme assay. KD and IC50 values were 51 and 8.9 nM, respectively. After subsequent sequence optimization, we successfully generated KRpep-2d (Ac-RRRRCPLYISYDPVCRRRR-NH2) that inhibited enzyme activity of K-Ras(G12D) with IC50 = 1.6 nM and significantly suppressed ERK-phosphorylation, downstream of K-Ras(G12D), along with A427 cancer cell proliferation at 30 µM peptide concentration. To our knowledge, this is the first report of a K-Ras(G12D)-selective inhibitor, contributing to the development and study of K-Ras(G12D)-targeting drugs.

Novel DOCK2-selective inhibitory peptide that suppresses B-cell line migration.

Dedicator of cytokinesis 2 (DOCK2) is a key molecule for lymphocyte activation and migration. DOCK2 interacts with Ras-related C3 botulinus toxin substrate 1 (Rac1, GTPase) and mediates the GDP-GTP exchange reaction, indicating that inhibitors against protein-protein interaction (PPI) between DOCK2 and Rac1 would be good drug candidates for treating immune-related disorders. Here, we report DOCK2-selective PPI inhibitory peptides discovered using random peptide T7 phage display technology. These peptides inhibited DOCK2 activity at nanomolar concentrations and were delivered to intracellular compartments by combination with cell-penetrating peptide (CPP). Consequently, one peptide, R4-DCpep-2(V2W/K4R/ox)-NH2 (Ac-RRRRCWARYHGYPWCRRRR-NH2), inhibited migration in human B lymphocyte MINO cell line at IC50 = 120 nM. To our knowledge, this is the first report of a DOCK2-selective peptide inhibitor; this study will contribute to the development of novel DOCK2-targeting immunosuppressive drugs.

Discovery of GPX4 inhibitory peptides from random peptide T7 phage display and subsequent structural analysis.

The phospholipid hydroperoxidase glutathione peroxidase (GPX4) is an enzyme that reduces lipid hydroperoxides in lipid membranes. Recently, GPX4 has been investigated as a target molecule that induces iron-dependent cell death (ferroptosis) selectively in cancer cells that express mutant Ras. GPX4 inhibitors have the potential to become novel anti-cancer drugs. However, there are no druggable pockets for conventional small molecules on the molecular surface of GPX4. To generate GPX4 inhibitors, we examined the use of peptides as an alternative to small molecules. By screening peptide libraries displayed on T7 phages, and analyzing the X-ray crystal structures of the peptides, we successfully identified one peptide that binds to near Sec73 of catalytic site and two peptides that bind to another site on GPX4. To our knowledge, this is the first study reporting GPX4 inhibitory peptides and their structural information.

Discovery of high-affinity BCL6-binding peptide and its structure-activity relationship.

B cell lymphoma 6 (BCL6) is a transcriptional repressor that interacts with its corepressors BcoR and SMRT. Since this protein-protein interaction (PPI) induces activation and differentiation of B lymphocytes, BCL6 has been an attractive drug target for potential autoimmune disease treatments. Here we report a novel BCL6 inhibitory peptide, F1324 (Ac-LWYTDIRMSWRVP-OH), which we discovered using phage display technology; we also discuss this peptide's structure-activity relationship (SAR). For BCL6(5-129) binding, KD and IC50 values of F1324 were 0.57 nM and 1 nM according to the results of an SPR analysis and cell-free ELISA assay, respectively. In contrast, BcoR(Arg498-514Pro) and SMRT(Leu1422-Arg1438) exhibited relatively weak micromole-order binding to BCL6. Furthermore, Fusion protein AcGFP-F1324 transiently expressed in HEK293T cells inhibited intracellular PPI in cell-based M2H assay. By examination of the truncation and fragmentation of F1324, the C-terminal sequence WRVP, which is similar to the BcoR(509-512) sequence WVVP, was identified as being critical for BCL6 binding. In addition, subsequent single-crystal X-ray diffraction analysis of F1324/BCL6(5-129) complex revealed that the high affinity of F1324 was caused by effective interaction of its side chains while its main chain structure was similar to that of BcoR(Arg498-514Pro). To our knowledge, F1324 is the strongest BCL6-binding peptide yet reported.

UGT1A1*6, 1A7*3, and 1A9*22 genotypes predict severe neutropenia in FOLFIRI-treated metastatic colorectal cancer in two prospective studies in Japan.

UNLABELLED: Retrospective studies have suggested that UDP-glucuronosyltransferase (UGT)1A1, UGT1A7, and UGT1A9 predict severe toxicity and efficacy of irinotecan-containing regimens. We prospectively evaluated the impact of UGT1A genotypes and haplotypes on severe toxicity and efficacy in patients treated with fluorouracil, leucovorin, and irinotecan combination chemotherapy (FOLFIRI) for metastatic colorectal cancer (mCRC) from the two prospective multicenter phase II studies in Japan. The FLIGHT1 study was a first-line FOLFIRI trial, and FLIGHT2 was a FOLFOX-refractory, second-line FOLFIRI trial. A total of 73 patients agreed to additional analysis, and were genotyped for UGT1A polymorphisms, UGT1A1*28 (TA6>TA7), UGT1A1*6 (211G>A), UGT1A1*27 (686C>A), UGT1A1*60 (-3279T>G), UGT1A1*93 (-3156G>A), UGT1A7 (-57T>G), UGT1A7*3 (387T>G, 622T>C), and UGT1A9*22 (T9>T10). Of 73 patients, 34 developed G3/4 severe hematological toxicities. The toxicities were significantly more frequent in patients with UGT1A1*6 (211A), UGT1A7 (387G), and UGT1A9*22 reference alleles (T9). Haplotype I, which consists of all favorable alleles, was associated with a significant reduction in hematologic toxicity (P = 0.031). In contrast, haplotype II, which contains four high-risk alleles, showed significantly higher hematologic toxicity than the other haplotypes (P = 0.010). Six out of seven patients who were homozygous for UGT1A1*28 or *6 experienced severe hematological toxicity despite the fact that their response rate was not impaired (42.9%). We concluded that UGT1A polymorphisms, especially UGT1A1*6, are important for the prediction of severe toxicity of FOLFIRI in northeast Asian populations. In this regard, haplotype analyses should substantially impact the prediction of severe hematological toxicities of FOLFIRI. ( CLINICAL TRIAL REGISTRATION: UMIN000002388 and UMIN000002476).

Inhibitory effects and specificity of synthetic sialyldendrimers toward recombinant human cytosolic sialidase 2 (NEU2).

Human sialidase 2 (NEU2) is a cytoplasmic sialidase that degrades sialylglycoconjugates, including glycoproteins and gangliosides, via hydrolysis of terminal sialic acids to produce asialo-type molecules. Here, we first report the inhibitory effects of a series of synthetic sialyldendrimers comprising three types [Dumbbell(1)6-S-Neu5Ac(6), Fan(0)3-S-Neu5Ac(3) and Ball(0)4-S-NeuAc(4)] toward recombinant human NEU2 in vitro. Among them, Dumbbell(1)6-S-Neu5Ac(6) exhibited the most potent inhibitory activity (concentration causing 50% inhibition (IC(50)), 0.4 ∼ 0.5 mM). In addition, NeuSLac and NeuSCel carrying thiosialyltrisaccharide moieties exhibited more potent inhibitory effects than NeuSGal and NeuSGlc carrying thiosialyldisaccharides. Docking models composed of NEU2 and the thiosialyloligosaccharide suggested that the active pocket of NEU2 prefers the second galactose-ß (Galß) to the glucose-ß (Glcß) residue in the trisaccharide structure, there being a hydrogen bond between the 4-hydroxy group of the second Galß and the side chain of the D46 residue of NEU2. The third Glcß residues of NeuSLac and NeuSCel were also predicted to be stabilized by hydrogen bonds with the side chains of the R21, R304, D358 and Y359 residues of NEU2. NEU2 mutants (D358A and Y359A) exhibited reduced affinity for NeuSLac carrying thiosialyltrisaccharide moieties, suggesting the significant roles of D358 and Y359 residues in recognition of thiosialyltrisaccharide moieties of NeuSLac bound in the active pocket of NEU2. Thus, the present sialyldendrimers could be utilized not only as a new class of NEU2 inhibitors but also as molecular probes for evaluating the biological functions of NEU2, including the catalytic activity and mechanism as to natural substrates carrying sialyloligosaccharides.

A randomized phase II trial to elucidate the efficacy of capecitabine plus cisplatin (XP) and S-1 plus cisplatin (SP) as a first-line treatment for advanced gastric cancer: XP ascertainment vs. SP randomized PII trial (XParTS II).

BACKGROUND: On the basis of international clinical trials, capecitabine plus cisplatin (XP) as a first-line treatment of advanced gastric cancer is considered a global standard regimen. However, the usefulness of XP as compared with S-1 plus cisplatin (SP), which is considered standard therapy in Japan, has not yet been assessed. METHODS/DESIGN: This is a multicenter randomized phase II trial to elucidate the efficacy of XP as compared with SP for first-line treatment of advanced gastric cancer. Patients with unresectable metastatic or recurrent gastric cancer, 20-74 years of age and human epidermal growth factor 2 (HER2)-negative status, will be assigned in a 1:1 ratio to receive either S-1 40 mg/m2 bid for 21 days plus cisplatin 60 mg/m2 (day 8) every 5-week cycle or capecitabine 1000 mg/m2 bid for 14 days plus cisplatin 80 mg/m2 (day 1) every 3-week cycle. Patients will be also asked to the analysis of tumor tissues for translational investigations. The Primary endpoint is progression-free survival and secondary endpoints are overall survival, time to treatment failure, tumor response rate and safety. These comparisons will also be evaluated in terms of biomarkers. Planned sample size is 100 (50 in each arm), which is appropriate for this trial. DISCUSSION: Fluoropyrimidine plus cisplatin combination is the standard regimen of the first line treatment for advanced gastric cancer. Both S-1 and capecitabine are the prodrug of 5-FU but differ from their process of metabolism. Result of this trial and translational research will provide the important clues to prepare the individualized therapy for advanced gastric cancer in the near future. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT01406249.

The importance of evaluation of DNA amplificability in KRAS mutation testing with dideoxy sequencing using formalin-fixed and paraffin-embedded colorectal cancer tissues.

OBJECTIVE: We evaluated DNA amplificability to achieve a 100% success rate in KRAS mutation testing with dideoxy sequencing using formalin-fixed and paraffin-embedded colorectal cancer tissue samples obtained from a recent clinical trial. METHODS: We evaluated the effects of deparaffinization, formalin fixation or storage time, and amplicon size on the amplificability of DNAs extracted from 19 formalin-fixed and paraffin-embedded colorectal cancer tissue samples. We subjected to KRAS mutation analysis 112 samples from metastatic colorectal cancer patients in 31 hospitals enrolled in a Phase II trial of a second-line FOLFIRI (5-fluorouracil+ leucovorin + irinotecan) + cetuximab regimen. RESULTS: Deparaffinization, formalin fixation and storage times did not appear to affect the recovery and amplificability of DNAs. However, amplicon size had a remarkable effect on the amplificability of DNAs. The smaller fragments with a size of ≤278 bp (96-278 bp) were successfully amplified with polymerase chain reaction in all samples tested, whereas the larger fragments with a size of ≥298 bp (298-565 bp) were not amplified. All samples from our clinical trial were successfully analyzed using three sets of primers with the amplicon sizes of 201, 221 and 240 bp, and KRAS mutations in exons 2 and 3 were detected in 49 of the 112 cases (43.8%). CONCLUSIONS: These data suggest that the evaluation of DNA amplificability and amplicon size is important for the success of mutation detection tests such as the KRAS test with dideoxy sequencing using formalin-fixed and paraffin-embedded tissue samples in the clinical setting.

Wilms' tumor 1 (WT1) peptide immunotherapy for gynecological malignancy.

BACKGROUND: The object of this study was to investigate the safety and clinical response of immunotherapy targeting the WT1 (Wilms' tumor 1) gene product in patients with gynecological cancer. PATIENTS AND METHODS: Twelve patients with WT1/human leukocyte antigen (HLA)-A*2402-positive gynecological cancer were included in a Phase II clinical trial of WT1 vaccine therapy. In all the patients, the tumors were resistant to standard therapy. The patients received intradermal injections of a HLA-A*2402-restricted, modified 9-mer WT1 peptide every week for 12 weeks. Tumor size, which was measured by computed tomography (CT), was determined every 4 weeks. The responses were analyzed according to Response Evaluation Criteria in Solid Tumors (RECIST). RESULTS: The protocol was well tolerated; only local erythema occurred at the WT1 vaccine injection site. The clinical responses were as follows: stable disease (SD) in 3 patients and progressive disease (PD) in 9 patients. No patients had a complete (CR) or partial response (PR). The disease control rate was 25.0%. CONCLUSION: Although a small, uncontrolled, nonrandomized trial, this study showed that WT1 vaccine therapy for patients with gynecological cancer was safe and produced a clinical response.

Synthesis of sialic acid derivatives having a C=C double bond substituted at the C-5 position and their glycopolymers.

Glycomonomers of sialic acid in which the acetamide group at C-5 was converted into two kinds of C=C double bond substituents were prepared and the fully protected glycomonomers were directly polymerized before deprotection steps. Radical polymerization with acrylamide in DMF in the presence of ammonium persulfate and N,N,N',N'-tetramethylethylenediamine proceeded smoothly and gave corresponding sialopolymers. Interestingly glycomonomers had hemagglutination inhibitory activities not only for H1N1 but also for H3N2 of human influenza virus strains.

Systematic syntheses of influenza neuraminidase inhibitors: a series of carbosilane dendrimers uniformly functionalized with thioglycoside-type sialic acid moieties.

In order to develop novel influenza sialidase inhibitors, we constructed a library of glycoclusters composed of twelve types of sialylated dendrimers with thioglycosidic linkage that are resistant to hydrolysis by the sialidases. These sialodendrimers were synthesized by condensation reaction between a thiosialoside modified on the aglycon terminal end by a thioacetyl group and twelve types of carbosilane dendrimers having brominated terminal ends under deacetylation conditions, and temporal re-protection was performed for purification. Removal of all protection of the glycodendrimers was accomplished by transesterification and subsequent saponification to provide corresponding water-soluble glycodendrimers in good yields. For investigation of the structure-activity relationship, dendrimer scaffolds having differences in number of the sugar moieties, such as 3-, 4-, 6- and 12-functionalized dendrimers, and in linkage patterns, such as normal aliphatic linkage, ether- and amide-linkages. Biological evaluations of these glycodendrimers showed that all of the ether- and amide-elongated compounds had inhibitory potencies for the influenza sialidases in the mM range, while compounds having normal aliphatic linkage did not have any activities except for a 12-functionalized compound.