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Rockville, MD, United States

Suzuki H.I.,University of Tokyo | Suzuki H.I.,Massachusetts Institute of Technology | Katsura A.,University of Tokyo | Matsuyama H.,University of Tokyo | And 2 more authors.

Cancer initiation and progression are defined by the behavior of cancer cells per se and the development of tumor tissues, both of which are modulated by crosstalk between cancer cells and the surrounding microenvironment. Advances in cancer research have highlighted the significance of constant evolution of the tumor microenvironment, leading to tumor formation, metastasis and refractoriness to therapy. MicroRNAs (miRNAs) are small non-coding RNAs that function as major players of posttranscriptional gene regulation in diverse biological processes. They function as both tumor suppressors and promoters in many aspects of the autonomous behavior of cancer cells. Theoretically, dysfunction in the gene regulatory networks of cancer cells is one of the major driving forces for alterations of ostensibly normal surrounding cells. In this context, the core targets of miRNAs, termed miRNA regulons, are currently being expanded to include various modulators of the tumor microenvironment. Recent advances have highlighted two important roles played by miRNAs in the evolution of tumor microenvironments: miRNAs in tumor cells transform the microenvironment via non-cell-autonomous mechanisms, and miRNAs in neighboring cells stabilize cancer hallmark traits. These observations epitomize the distal and proximal functions of miRNAs in tumor microenvironments, respectively. Such regulation by miRNAs affects tumor angiogenesis, immune invasion and tumor-stromal interactions. This review summarizes recent findings on the mechanisms of miRNA-mediated regulation of tumor microenvironments, with a perspective on the design of therapeutic interventions. © 2015 Macmillan Publishers Limited All rights reserved. Source

Kawashima Y.,U.S. National Institutes of Health | Geleoc G.S.G.,University of Virginia | Geleoc G.S.G.,Harvard University | Kurima K.,U.S. National Institutes of Health | And 13 more authors.
Journal of Clinical Investigation

Inner ear hair cells convert the mechanical stimuli of sound, gravity, and head movement into electrical signals. This mechanotransduction process is initiated by opening of cation channels near the tips of hair cell stereocilia. Since the identity of these ion channels is unknown, and mutations in the gene encoding transmembrane channel-like 1 (TMC1) cause hearing loss without vestibular dysfunction in both mice and humans, we investigated the contribution of Tmc1 and the closely related Tmc2 to mechanotransduction in mice. We found that Tmc1 and Tmc2 were expressed in mouse vestibular and cochlear hair cells and that GFP-tagged TMC proteins localized near stereocilia tips. Tmc2 expression was transient in early postnatal mouse cochlear hair cells but persisted in vestibular hair cells. While mice with a targeted deletion of Tmc1 (Tmc1Δ mice) were deaf and those with a deletion of Tmc2 (Tmc2Δ mice) were phenotypically normal, Tmc1ΔTmc2Δ mice had profound vestibular dysfunction, deafness, and structurally normal hair cells that lacked all mechanotransduction activity. Expression of either exogenous TMC1 or TMC2 rescued mechanotransduction in Tmc1ΔTmc2Δ mutant hair cells. Our results indicate that TMC1 and TMC2 are necessary for hair cell mechanotransduction and may be integral components of the mechanotransduction complex. Our data also suggest that persistent TMC2 expression in vestibular hair cells may preserve vestibular function in humans with hearing loss caused by TMC1 mutations. Source

Zhang J.,U.S. National Institutes of Health | Qiu S.,U.S. National Institutes of Health | Qiu S.,Dickinson College | Zhang Y.,U.S. National Institutes of Health | And 7 more authors.
Anticancer Research

Background/Aim: To determine if early passage tumor cells obtained from patients with mesothelioma continue to express the tumor differentiation antigen mesothelin and their sensitivity to the anti-mesothelin immunotoxin SS1P. Materials and Methods: Cell cultures were established from ascites or pleural effusion of 6 peritoneal and 3 pleural mesothelioma patients, respectively. These cells were evaluated for mesothelin expression by immunohistochemistry and flow cytometry. Results: Although mesothelin was highly expressed in tumor biopsies of all patients, only 3 out of 9 malignant effusions from these patients when grown in short-term culture showed strong mesothelin positivity by IHC. By flow cytometry, the number of mesothelin sites per cell was variable ranging from 580 to 210,000 sites/cell. Cells with strong mesothelin expression by IHC and increased number of mesothelin sites/cell were sensitive to SS1P. Conclusions: Most mesothelioma tumors loose mesothelin when grown in vitro and the sensitivity of these cells to SS1P is dependent on the number of mesothelin sites/cell. Source

Sriwilaijaroen N.,Thammasat University | Sriwilaijaroen N.,Chubu University | Magesh S.,Thammasat University | Magesh S.,Otsuka Maryland Medicinal Laboratories Inc. | And 13 more authors.
Journal of Medicinal Chemistry

People throughout the world continue to be at risk for death from influenza A virus, which is always creating a new variant. Here we present a new effective and specific anti-influenza viral neuraminidase (viNA) inhibitor, 9-cyclopropylcarbonylamino-4-guanidino-Neu5Ac2en (cPro-GUN). Like zanamivir, it is highly effective against N1-N9 avian and N1-N2 human viNAs, including H274Y oseltamivir-resistant N1 viNA, due to its C-6 portion still being anchored in the active site, different from the disruption of oseltamivir's C-6 anchoring by H274Y mutation. Unlike zanamivir, no sialidase inhibitory activity has been observed for cPro-GUN against huNeu1-huNeu4 enzymes. Broad efficacy of cPro-GUN against avian and human influenza viruses in cell cultures comparable to its sialidase inhibitory activities makes cPro-GUN ideal for further development for safe therapeutic or prophylactic use against both seasonal and pandemic influenza. © 2016 American Chemical Society. Source

Zhang Y.,Otsuka Maryland Medicinal Laboratories Inc. | Tian D.,University of Minnesota | Matsuyama H.,Otsuka Maryland Medicinal Laboratories Inc. | Hamazaki T.,Osaka City University | And 6 more authors.
Journal of Biomolecular Screening

Transport of ADP and ATP across mitochondria is one of the primary points of regulation to maintain cellular energy homeostasis. This process is mainly mediated by adenine nucleotide translocase (ANT) located on the mitochondrial inner membrane. There are four human ANT isoforms, each having a unique tissue-specific expression pattern and biological function, highlighting their potential as drug targets for diverse clinical indications, including male contraception and cancer. In this study, we present a novel yeast-based high-throughput screening (HTS) strategy to identify compounds inhibiting the function of ANT. Yeast strains generated by deletion of endogenous proteins with ANT activity followed by insertion of individual human ANT isoforms are sensitive to cell-permeable ANT inhibitors, which reduce proliferation. Screening hits identified in the yeast proliferation assay were characterized in ADP/ATP exchange assays employing recombinant ANT isoforms expressed in isolated yeast mitochondria and Lactococcus lactis as well as by oxygen consumption rate in mammalian cells. Using this approach, closantel and CD437 were identified as broad-spectrum ANT inhibitors, whereas leelamine was found to be a modulator of ANT function. This yeast "knock-out/knock-in" screening strategy is applicable to a broad range of essential molecular targets that are required for yeast survival. © 2015 Society for Laboratory. Source

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