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Two novel compounds, JBIR-07 (1) and -08 (2), were isolated from a large-scale culture of Streptomyces versipellis 4083-SVS6. These compounds were determined to be novel decanedienamide derivatives, (6E, 8Z)-3-hydroxy-8-(hydroxymethyl)-2,6-dimethyldeca-6,8-dienamide (1) and (6Z, 8E)-3-hydroxy-6-(hydroxymethyl)-2,8-dimethyldeca-6,8-dienamide (2), based on spectroscopic data. [ABSTRACT FROM AUTHOR]

Protein-protein interactions (PPIs) play key roles in all cellular processes and hence are useful as potential targets for new drug development. To facilitate the screening of PPI inhibitors as anticancer drugs, the authors have developed a highthroughput screening (HTS) system using an in vitro protein fragment complementation assay (PCA) with monomeric Kusabira-Green fluorescent protein (mKG). The in vitro PCA system was established by the topological formation of a functional complex between 2 split inactive mKG fragments fused to target proteins, which fluoresces when 2 target proteins interact to allow complementation of the mKG fragments. Using this assay system, the authors screened inhibitors for TCF7/β-catenin, PAC1/PAC2, and PAC3 homodimer PPIs from 123,599 samples in their natural product library. Compound TB1 was identified as a specific inhibitor for PPI of PAC3 homodimer. TB1 strongly inhibited the PPI of PAC3 homodimer with an IC50 value of 0.020 μM and did not inhibit PPI between TCF7/β-catenin and PAC1/PAC2 even at a concentration of 250 μM. The authors thus demonstrated that this in vitro PCA system applicable to HTS in a 1536-well format is capable of screening for PPI inhibitors from a huge natural product library. [ABSTRACT FROM AUTHOR]

Sequence analysis of ketosynthase domain amplicons from Streptomyces bicolor NBRC 12746T revealed the presence of previously unreported type I polyketide synthases (PKS-I) genes. The clustering of these genes with the reference PKS-1 sequences suggested the possibility to produce a polyene compound similar to pimaricin. Thus, the cultured sample from NBRC 12746T was analyzed for the production of polyene compounds. The strain produced an antifungal compound which displayed the UV absorption spectrum of tetraene macrolides. The structure determination based on the spectroscopic analysis of the purified compound resulted in the identification of a novel pimaricin analog JBIR-13 ( 1). This study therefore strongly suggested that a careful analysis of PKS-I genes can provide valuable information in the search of novel bioactive compounds within a class predicted from phylogenetic analysis. [ABSTRACT FROM AUTHOR]

Small interfering RNAs (siRNAs) are expected to have a medical application in human therapy as drugs with a high specificity for their molecular target mRNAs. RecQL1 DNA helicase in the human RecQ helicase family participates in DNA repair and recombination pathways in the cell cycle of replication. Silencing the RecQL1 expression by RecQL1-siRNA induces mitotic death in vitro specifically in growing cancer cells. By contrast, the same RecQL1 silencing does not affect the growth of normal cells, emphasizing that RecQL1 helicase is an ideal molecular target for cancer therapy. In this study, we show that local and systemic administration of RecQL1-siRNA mixed with polyethyleneimine polymer or cationic liposomes prevented cancer cell proliferation in vivo in mouse models of cancer without noticeable adverse effects. The results indicate that RecQL1-siRNA in a complex with a cationic polymer is a very promising anticancer drug candidate, and that in particular, RecQL1-siRNA formulated with a cationic liposome has an enormous potential to be used by intravenous injection for therapy specific for liver cancers, including metastasized cancers from the colon and pancreas. ( Cancer Sci 2008; 99: 1227–1236) [ABSTRACT FROM AUTHOR]

RecQL1 DNA helicase of the human RecQ helicase family participates in DNA repair and recombination pathways during cell-cycle replication. When we examined the effect of RecQL1 suppression on cell growth, we found that RecQL1 silencing by small interference RNA efficiently prevented proliferation of a wide range of cancer cells by inducing mitotic catastrophe and mitotic cell death. In contrast, such mitotic cell death was not seen in the growing normal fibroblasts used as controls, even if RecQL1 expression was fully downregulated. Our results support the hypothesis that endogenous DNA damage that occurs during DNA replication and remains unrepaired in cancer cells due to RecQL1 silencing induces cancer cell-specific mitotic catastrophe through a less-strict checkpoint in cancer cells than in normal cells. We speculate that normal cells are exempt from such mitotic cell death, despite slow growth, because cell-cycle progression is controlled strictly by a strong checkpoint system that detects DNA damage and arrests progression of the cell cycle until DNA damage is repaired completely. These results suggest that RecQL1 helicase is an excellent molecular target for cancer chemotherapy. ( Cancer Sci 2008; 99: 71–80) [ABSTRACT FROM AUTHOR]

Abstract: Although small interfering RNA (siRNA) is a potentially useful therapeutic approach to silence the targeted gene of a particular disease, its use is limited by its stability in vivo. For the liver parenchymal cell (PC)-selective delivery of siRNA, siRNA was complexed with galactosylated cationic liposomes. Galactosylated liposomes/siRNA complex exhibited a higher stability than naked siRNA in plasma. After intravenous administration of a galactosylated liposomes/siRNA complex, the siRNA did not undergo nuclease digestion and urinary excretion and was delivered efficiently to the liver and was detected in PC rather than liver non-parenchymal cells (NPC). Endogenous gene (Ubc13 gene) expression in the liver was inhibited by 80% when Ubc13–siRNA complexed with galactosylated liposomes was administered to mice at a dose of 0.29nmol/g. In contrast, the bare cationic liposomes did not induce any silencing effect on Ubc13 gene expression. These results indicated that galactosylated liposomes/siRNA complex could induce gene silencing of endogenous hepatic gene expression. The interferon responses by galactosylated liposomes/siRNA complex were controlled by optimization of the sequence of siRNA. Also no liver toxicity due to galactosylated liposomes/siRNA complex was observed under any of the conditions tested. In conclusion, we demonstrated the hepatocyte-selective gene silencing by galactosylated liposomes following intravenous administration. [Copyright &y& Elsevier]

Describes the first unambiguous assignment of the Bacillus subtilis ypgA gene product as type 2 isopentyl diphosphate (IPP) isomerase and the enzymatic properties of the ypgA gene products overexpressed in Escherichia coli. Ability of the enzyme to catalyze the reverse reaction in the presence of both the cofactors; Indication that disruption of the ypgA3 gene as not lethal to B. subtilis; Indication that Bacillus ypgA3 gene is fni, a nonessential gene encoding type 2 IPP isomerase.

Precursors for isoprenoid synthesis are essential in all organisms. These compounds are synthesized by one of two known routes: the well characterized mevalonate pathway or a recently discovered non-mevalonate route which is used in many bacteria and human pathogens. Since the second pathway is both vital and unlike any found in humans, enzymes catalysing reactions along this synthetic route are possible drug targets. The structure of one such enzyme from the thermophilic bacterium Thermus thermophilus has been solved to high resolution in the presence of substrate and with a substrate analogue. Enzyme co-crystallized with substrate shows only one product, cytosine monophosphate (CMP), in the active site. At the high resolution of the refinement (1.6 Å) the positions and coordination of the magnesium ions in the active site are clearly seen. [ABSTRACT FROM AUTHOR]

Reports on the use of a gene cluster clone from a Streptomyces strain to catalyze an isomerization process. Purification of the recombinant product; Analysis of the chemical reaction by nuclear magnetic resonance; Suitability of the enzyme as a molecular target for the screening of antibacterial drugs.

Describes the cloning and functional analyses of the five open reading frames found in the flanking regions of the 3-hydroxy-3-methylglutaryl coenzyme A reductase gene (hmgr) from Streptomyces sp. strain CL190. Importance of the hmgr gene and orfABCDE for the mevalonate pathway and the formation of a gene cluster in the genome.

An in vitro assay system using patient-derived tumor models represents a promising preclinical cancer model that replicates the disease better than traditional cell culture models. Patient-derived tumor organoid (PDO) and patient-derived tumor xenograft (PDX) models have been previously established from different types of human tumors to recapitulate accurately and efficiently their tissue architecture and function. However, these models have low throughput and are challenging to construct. Thus, the present study aimed to establish a simple in vitro high-throughput assay system using PDO and PDX models. Furthermore, the current study aimed to evaluate different classes of anticancer drugs, including chemotherapeutic, molecular targeted and antibody drugs, using PDO and PDX models. First, an in vitro high-throughput assay system was constructed using PDO and PDX established from solid and hematopoietic tumors cultured in 384-well plates to evaluate anticancer agents. In addition, an in vitro evaluation system of the immune response was developed using PDO and PDX. Novel cancer immunotherapeutic agents with marked efficacy have been used against various types of tumor. Thus, there is an urgent need for in vitro functional potency assays that can simulate the complex interaction of immune cells with tumor cells and can rapidly test the efficacy of different immunotherapies or antibody drugs. An evaluation system for the antibody-dependent cellular cytotoxic activity of anti-epidermal growth factor receptor antibody and the cytotoxic activity of activated lymphocytes, such as cytotoxic T lymphocytes and natural killer cells, was constructed. Moreover, immune response assay systems with bispecific T-cell engagers were developed using effector cells. The present results demonstrated that in vitro assay systems using PDO and PDX may be suitable for evaluating anticancer agents and immunotherapy potency with high reproducibility and simplicity. [ABSTRACT FROM AUTHOR]

The article focuses on a research regarding the structure of the JBIR-107, a metabolite obtained from the culture of Streptomyces tateyamensis NBRC 105047 strain. It informs that the JBIR-107 has 5-acetamido-6-(4-(methyl(2-oxo-3-phe-nylpropyl )aniino)phenyl)-4-oxohexanoic acid structure, which has been identified through mass spectrometry and nuclear magnetic resonance (NMR) analysis.

The article discusses a study regarding the isolation of JBIR-66 compound from the culture broth of tunicate-derived actinomycete, saccharopolyspora sp. SS081219JE-28. It mentions that JBIR-66 was purified with macrolactin E, gilvocarcin M, and V. The SS081219JE strain was cultured in 50 ml test tubes containing 1.0% starch and 1.0 meat extract. Moreover, the study indicates that new species of actinobacteria could produce bioactive compounds consisting of skeletal structures.

The article discusses the process for producing new compounds from marine sponge, Desmospongiae. It notes that the novel compounds JBIR-37 (1) and -38 (2) were isolated from Acremonium sp. fungus derived from the sponge. The results showed that the structures 1 and 2 were determined as glycosyl benzene, which did not show any cytotoxic effects in human cervical carcinoma and human malignant pleural mesothelioma.

The article presents a study which isolates a new aspochracin derivative, JBIR-15, from Aspergillus sclertiorum Huber Sp080903f04, a sponge-derived fungus. JBIR-15 was isolated with aspochracin from the culture broth of a A. sclertiorum. The structure of JBIR-15 was determined to be N-demethyl aspochracin at the alanyl residue on the basis of extensive nuclear magnetic resonance (NMR) and mass spectrometry (MS). It is the first derivative of which N-methyl alanine was replaced by alanine.

Patient-derived tumor organoids (PDOs) represent a promising preclinical cancer model that better replicates disease, compared with traditional cell culture models. We have established PDOs from various human tumors to accurately and efficiently recapitulate the tissue architecture and function. Molecular targeted therapies with remarkable efficacy are currently in use against various tumors. Thus, there is a need for in vitro functional-potency assays that can be used to test the efficacy of molecular targeted drugs and model complex interactions between immune cells and tumor cells to evaluate the potential for cancer immunotherapy. This study represents an in vitro evaluation of different classes of molecular targeted drugs, including small-molecule inhibitors, monoclonal antibodies, and an antibody-drug conjugate, using lung PDOs. We evaluated epidermal growth factor receptor and human epidermal growth factor receptor 2 (HER2) inhibitors using a suitable high-throughput assay system. Next, the antibody-dependent cellular cytotoxicity (ADCC) activity of an anti-HER2 monoclonal antibody was evaluated to visualize the interactions of immune cells with PDOs during ADCC responses. Moreover, an evaluation system was developed for the immune checkpoint inhibitors, nivolumab and pembrolizumab, using PDOs. Our results demonstrate that the in vitro assay systems using PDOs were suitable for evaluating molecular targeted drugs under conditions that better reflect pathological conditions. [ABSTRACT FROM AUTHOR]

We have developed a highly sensitive promoter trap vector system using transposons to generate reporter cells with high efficiency. Using an EGFP/luciferase reporter cell clone responsive to forskolin, which is thought to activate adenylate cyclase, isolated from human chronic myelogenous leukemia cell line K562, we found several compounds unexpectedly caused reporter responses. These included tyrosine kinase inhibitors such as dasatinib and cerdulatinib, which were seemingly unrelated to the forskolin-reactive pathway. To investigate whether any other clones of forskolin-responsive cells would show the same response, nine additional forskolin-responsive clones, each with a unique integration site, were generated and quantitatively evaluated by luciferase assay. The results showed that each clone represented different response patterns to the reactive compounds. Also, it became clear that each of the reactive compounds could be profiled as a unique pattern by the 10 reporter clones. When other TKIs, mainly bcr-abl inhibitors, were evaluated using a more focused set of five reporter clones, they also showed unique profiling. Among them, dasatinib and bosutinib, and imatinib and bafetinib showed homologous profiling. The tyrosine kinase inhibitors mentioned above are approved as anticancer agents, and the system could be used for similarity evaluation, efficacy prediction, etc., in the development of new anticancer agents. [ABSTRACT FROM AUTHOR]