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Qingfei Zheng, Shoufeng Wang, Rijing Liao, Wen Liu
Side-ring-modified thiostrepton (TSR) derivatives that vary in their quinaldic acid (QA) substitution possess more potent biological activities and better pharmaceutical properties than the parent compound. In this work, we sought to introduce fluorine onto C-7' or C-8' of the TSR QA moiety via precursor-directed mutational biosynthesis to obtain new TSR variants. Unexpectedly, instead of the target product, the exogenous chemical feeding of 7-F-QA into the ΔtsrT mutant strain resulted in a unique TSR analog with an incomplete side-ring structure and an unoxidized QA moiety (1)...
October 21, 2016: ACS Chemical Biology
Noemí Bahamontes-Rosa, María G Gomez-Lorenzo, Joël Lelièvre, Ane Rodriguez Alejandre, María Jesus Almela, Sonia Lozano, Esperanza Herreros, Francisco-Javier Gamo
BACKGROUND: Drugs that kill or inhibit Plasmodium gametocytes in the human host could potentially synergize the impact of other chemotherapeutic interventions by blocking transmission. To develop such agents, reliable methods are needed to study the in vitro activity of compounds against gametocytes. This study describes a novel assay for characterizing the activity of anti-malarial drugs against the later stages of Plasmodium falciparum gametocyte development using real-time PCR (qPCR)...
2016: Malaria Journal
Akira Maekawa, Kenichi Kohashi, Masaaki Kuda, Kunio Iura, Takeaki Ishii, Makoto Endo, Tetsuya Nakatsura, Yukihide Iwamoto, Yoshinao Oda
BACKGROUND: Synovial sarcoma (SS) is a soft tissue sarcoma of unknown histogenesis. Most metastatic or unresectable cases are incurable. Novel antitumor agents and precise prognostication are needed for SS patients. The protein forkhead box M1 (FOXM1), which belongs to the FOX family of transcription factors, is considered to be an independent predictor of poor survival in many cancers and sarcomas, but the prognostic implications and oncogenic roles of FOXM1 in SS are poorly understood...
2016: BMC Cancer
Katsumi Doi, Yasuhiro Fujino, Yuko Nagayoshi, Toshihisa Ohshima, Seiya Ogata
Streptomyces laurentii ATCC 31255 produces thiostrepton, a thiopeptide class antibiotic. Here, we report the complete genome sequence for this strain, which contains a total of 8,032,664 bp, 7,452 predicted coding sequences, and a G+C content of 72.3%.
2016: Genome Announcements
Takamichi Ito, Kenichi Kohashi, Yuichi Yamada, Takeshi Iwasaki, Akira Maekawa, Masaaki Kuda, Daichi Hoshina, Riichiro Abe, Masutaka Furue, Yoshinao Oda
BACKGROUND: The prognosis of angiosarcoma is poor and a novel treatment option for the disease is desired. The aim of this study was to investigate the prognostic significance of Forkhead box M1 (FOXM1), a transcription factor that regulates cell-cycle progression and various crucial processes in tumor progression, and its potential as a new therapeutic target. METHODS: We investigated 125 angiosarcoma clinical samples (94 primary lesions and 31 metastatic lesions in 94 patients) and a human angiosarcoma cell line (HAMON) using immunohistochemical staining and molecular biological approaches...
2016: Journal of Cancer
Na Yang, Tai-Cheng Zhou, Xiu-xia Lei, Chang Wang, Min Yan, Zi-Feng Wang, Wei Liu, Jian Wang, Kai-Hua Ming, Bi-Cheng Wang, Bang-Lao Xu, Quentin Liu
BACKGROUND/AIM: Triple-negative breast cancer (TNBC) represents a particular clinical challenge because these cancers do not respond to endocrine therapy or other available targeted agents. The lack of effective agents and obvious targets are major challenges in treating TNBC. In this study we explored the cytostatic effect of thiazole ring containing antibiotic drug thiostrepton on TNBC cell lines and investigated the molecular mechanism. METHODS: Cell viability was measured by MTT assay...
2016: Cellular Physiology and Biochemistry
Anthony J Blaszczyk, Alexey Silakov, Bo Zhang, Stephanie J Maiocco, Nicholas D Lanz, Wendy L Kelly, Sean J Elliott, Carsten Krebs, Squire J Booker
TsrM, an annotated radical S-adenosylmethionine (SAM) enzyme, catalyzes the methylation of carbon 2 of the indole ring of L-tryptophan. Its reaction is the first step in the biosynthesis of the unique quinaldic acid moiety of thiostrepton A, a thiopeptide antibiotic. The appended methyl group derives from SAM; however, the enzyme also requires cobalamin and iron-sulfur cluster cofactors for turnover. In this work we report the overproduction and purification of TsrM and the characterization of its metallocofactors by UV-visible, electron paramagnetic resonance, hyperfine sublevel correlation (HYSCORE), and Mössbauer spectroscopies as well as protein-film electrochemistry (PFE)...
March 16, 2016: Journal of the American Chemical Society
Feifei Zhang, Chaoxuan Li, Wendy L Kelly
The thiopeptides are a family of ribosomally synthesized and post-translationally modified peptide metabolites, and the vast majority of thiopeptides characterized to date possess one highly modified macrocycle. A few members, including thiostrepton A, harbor a second macrocycle that incorporates a quinaldic acid moiety and the four N-terminal residues of the peptide. The antibacterial properties of thiostrepton A are well established, and its recently discovered ability to inhibit the proteasome has additional implications for the development of antimalarial and anticancer therapeutics...
February 19, 2016: ACS Chemical Biology
Takamichi Ito, Kenichi Kohashi, Yuichi Yamada, Akira Maekawa, Masaaki Kuda, Masutaka Furue, Yoshinao Oda
AIMS: Forkhead box M1 (FoxM1) is a transcription factor that regulates cell-cycle progression and tumour progression, but limited information is available regarding its clinical significance in melanoma. The aim of this study was to investigate the potency of FoxM1 as a therapeutic target in melanoma. METHODS AND RESULTS: We investigated 60 melanoma clinical samples and a melanoma WM266-4 cell line using immunohistochemical staining and molecular biological approaches...
July 2016: Histopathology
Akira Maekawa, Kenichi Kohashi, Nokitaka Setsu, Masaaki Kuda, Kunio Iura, Takeaki Ishii, Tomoya Matsunobu, Tetsuya Nakatsura, Yukihide Iwamoto, Yoshinao Oda
Leiomyosarcoma (LMS) of soft tissue is a sarcoma with smooth-muscle differentiation, and conventional chemotherapy does not improve its outcome. The application of novel antitumor agents and precise prognostication has been demanded. The expression of the protein Forkhead box M1 (FOXM1), a member of the FOX family, is considered an independent predictor of poor survival in many cancers and sarcomas. However, the expression status of FOXM1 in LMS is poorly understood. The purposes of this study were to examine the correlation between the expression of FOXM1 and clinicopathologic or prognostic factors and to clarify the efficacy of FOXM1 target therapy in LMS...
January 2016: Cancer Science
Kengo Sakihara, Jumpei Maeda, Kosuke Tashiro, Yasuhiro Fujino, Satoru Kuhara, Toshihisa Ohshima, Seiya Ogata, Katsumi Doi
Streptomyces azureus ATCC 14921 belongs to the Streptomyces cyaneus cluster and is known to be a thiostrepton producer. Here, we report a draft genome sequence for this strain, consisting of 350 contigs containing a total of 8,790,525 bp, 8,164 predicted coding sequences, and a G+C content of 70.9%.
2015: Genome Announcements
Alhosna Benjdia, Stéphane Pierre, Carmen Gherasim, Alain Guillot, Manon Carmona, Patricia Amara, Ruma Banerjee, Olivier Berteau
Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a novel class of natural products including several antibiotics and bacterial toxins. In countless RiPP biosynthetic pathways, cobalamin-dependent radical SAM (B12/rSAM) enzymes play a pivotal role. In the biosynthetic pathway of the antibiotic and anti-cancer agent thiostrepton A, TsrM, a B12/rSAM enzyme, catalyses the transfer of a methyl group to an electrophilic carbon atom of tryptophan. Here we show that methylcob(III)alamin is the probable physiological enzyme cofactor, and cob(II)alamin rather than cob(I)alamin is a key reaction intermediate...
2015: Nature Communications
Cullen L Myers, Emily G Kuiper, Pei C Grant, Jennifer Hernandez, Graeme L Conn, John F Honek
Resistance to the antibiotic thiostrepton, in producing Streptomycetes, is conferred by the S-adenosyl-L-methionine (SAM)-dependent SPOUT methyltransferase Tsr. For this and related enzymes, the roles of active site amino acids have been inadequately described. Herein, we have probed SAM interactions in the Tsr active site by investigating the catalytic activity and the thermodynamics of SAM binding by site-directed Tsr mutants. Two arginine residues were demonstrated to be critical for binding, one of which appears to participate in the catalytic reaction...
October 24, 2015: FEBS Letters
Chao-Yang Lai, Da-Wei Yeh, Chih-Hao Lu, Yi-Ling Liu, Li-Rung Huang, Cheng-Yuan Kao, Huan-Yuan Chen, Chi-Ying F Huang, Chung-Hsing Chang, Yunping Luo, Rong Xiang, Tsung-Hsien Chuang
Activation of TLR7-9 has been linked to the pathogenesis of autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, and psoriasis. Thus, therapeutic applications of antagonists of these TLRs for such disorders are being investigated. Bortezomib (Velcade) is a proteasome inhibitor known to suppress activation of these TLRs. To identify novel TLR7-9 inhibitors, we searched the Gene Expression Omnibus database for gene expression profiles of bortezomib-treated cells. These profiles were then used to screen the Connectivity Map database for chemical compounds with similar functions as bortezomib...
October 15, 2015: Journal of Immunology: Official Journal of the American Association of Immunologists
Keisuke Wada, Jyumpei Kobayashi, Megumi Furukawa, Katsumi Doi, Takashi Ohshiro, Hirokazu Suzuki
Effective utilization of microbes often requires complex genetic modification using multiple antibiotic resistance markers. Because a few markers have been used in Geobacillus spp., the present study was designed to identify a new marker for these thermophiles. We explored antibiotic resistance genes functional in Geobacillus kaustophilus HTA426 and identified a thiostrepton resistance gene (tsr) effective at 50 °C. The tsr gene was further used to generate the mutant tsr(H258Y) functional at 55 °C. Higher functional temperature of the mutant was attributable to the increase in thermostability of the gene product because recombinant protein produced from tsr(H258Y) was more thermostable than that from tsr...
2016: Bioscience, Biotechnology, and Biochemistry
Francesca Consolaro, Giuseppe Basso, Sadaf Ghaem-Magami, Eric W-F Lam, Giampietro Viola
The Forkhead box protein M1 (FOXM1) is a transcription factor that plays a central role in the regulation of cell cycle, proliferation, DNA repair, and apoptosis. FOXM1 is overexpressed in many human tumors and its upregulation has been linked to high proliferation rates and poor prognosis. We therefore studied the role of FOXM1 in B-lymphoblastic leukemia (B-ALL) in order to understand whether FOXM1 could be a key target for leukemia therapy. RT-PCR and western blot analysis were carried out in a small cohort of pediatric B-ALL patients to evaluate FOXM1 levels...
October 2015: International Journal of Oncology
Qingfei Zheng, Qinglan Wang, Shoufeng Wang, Jiequn Wu, Qian Gao, Wen Liu
Thiostrepton (TSR) is an archetypal thiopeptide antibiotic possessing a quinaldic acid (QA) moiety in the side ring system. According to the mechanism of TSR previously known to target bacterial ribosome, we recently designed and biosynthesized several TSR derivatives that varied in QA substitution. Utilizing these thiopeptide antibiotics to treat the intracellular pathogen Mycobacterium marinum, we herein report a novel mode of action of TSRs, which induce ER stress-mediated autophagy to enhance host cell defense...
August 20, 2015: Chemistry & Biology
Yi Chen, Eliza A Ruben, Jayakumar Rajadas, Nelson N H Teng
OBJECTIVE: Using TCGA database, we had demonstrated that aberrantly activated Forkhead box M1 (FOXM1) correlates to worse overall survival in a subgroup of platinum resistant patients. Application of thiostrepton, a natural thiazole antibiotics that inhibits FOXM1 transcription activity in the clinic is hampered by difficulties in synthesis, degradation potential, and solubility. In this study, we aim to identify potential FOXM1 small molecule inhibitors to develop a new class of therapeutic agents to address the challenges in treating chemotherapy resistant EOC...
August 1, 2015: Bioorganic & Medicinal Chemistry
Maqbool Ahmed, Azhar R Hussain, Abdul K Siraj, Shahab Uddin, Nasser Al-Sanea, Fouad Al-Dayel, Mohammed Al-Assiri, Shaham Beg, Khawla S Al-Kuraya
BACKGROUND: Cross-talk between deregulated signaling pathways in cancer cells causes uncontrolled growth and proliferation. These cancers cells become more aggressive and quickly develop resistance to therapy. Therefore targeting of these deregulated pathways simultaneously can result in efficient cell death of cancer cells. In this study we investigated co-expression of Cox-2 and FoxM1 in a cohort of colorectal carcinoma (CRC) samples and also examined whether inhibition of Cox-2 and FoxM1 simultaneously can lead to inhibition of cell viability and induction of apoptosis in colorectal cancer cell lines and in vivo xenografts...
2015: Molecular Cancer
S-Y Ju, C-Y F Huang, W-C Huang, Y Su
Accumulating evidence shows that colorectal cancer stem cells (CRSCs) are largely responsible for the metastasis and relapse of colorectal cancer (CRC) after therapy. Hence, identifying new agents that specifically target CRSCs would help improve the effectiveness of current CRC therapies. To accelerate identification of agents targeting CRSCs, the Connectivity Map (CMap) approach was used. Among the top-ranked candidates, thiostrepton, a thiazole antibiotic, was selected for further investigation because of its known tumoricidal activity...
2015: Cell Death & Disease
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