1
|
El-Desoky AHH, Inada N, Maeyama Y, Kato H, Hitora Y, Sebe M, Nagaki M, Kai A, Eguchi K, Inazumi T, Sugimoto Y, Frisvad JC, Williams RM, Tsukamoto S. Taichunins E-T, Isopimarane Diterpenes and a 20- nor-Isopimarane, from Aspergillus taichungensis (IBT 19404): Structures and Inhibitory Effects on RANKL-Induced Formation of Multinuclear Osteoclasts. JOURNAL OF NATURAL PRODUCTS 2021; 84:2475-2485. [PMID: 34464116 DOI: 10.1021/acs.jnatprod.1c00486] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Fifteen new isopimarane-type diterpenes, taichunins E-S (1-15), and a new 20-nor-isopimarane, taichunin T (16), together with four known compounds were isolated from Aspergillus taichungensis (IBT 19404). The structures of these new compounds were determined by NMR and mass spectroscopy, and their absolute configurations were analyzed by NOESY and TDDFT calculations of ECD spectra. Taichunins G, K, and N (3, 7, and 10) completely inhibited the receptor activator of nuclear factor-κB ligand (RANKL)-induced formation of multinuclear osteoclasts in RAW264 cells at 5 μM, with 3 showing 92% inhibition at a concentration of 0.2 μM.
Collapse
|
2
|
Aoyagi Y, Nomura S, Horiba K, Shikano R, Omura Y, Omiya H, Fukuzawa S, Yano R, Williams RM, Takeya K, Hitotsuyanagi Y. Lipase TL®-mediated kinetic resolution of glycerol analogues: Efficient convergent route to both enantiomeric glycerol units. Tetrahedron Lett 2021. [DOI: 10.1016/j.tetlet.2021.153138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
3
|
Fraley AE, Tran HT, Kelly SP, Newmister SA, Tripathi A, Kato H, Tsukamoto S, Du L, Li S, Williams RM, Sherman DH. Flavin-Dependent Monooxygenases NotI and NotI' Mediate Spiro-Oxindole Formation in Biosynthesis of the Notoamides. Chembiochem 2020; 21:2449-2454. [PMID: 32246875 PMCID: PMC7483341 DOI: 10.1002/cbic.202000004] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 04/04/2020] [Indexed: 11/08/2022]
Abstract
The fungal indole alkaloids are a unique class of complex molecules that have a characteristic bicyclo[2.2.2]diazaoctane ring and frequently contain a spiro-oxindole moiety. While various strains produce these compounds, an intriguing case involves the formation of individual antipodes by two unique species of fungi in the generation of the potent anticancer agents (+)- and (-)-notoamide A. NotI and NotI' have been characterized as flavin-dependent monooxygenases that catalyze epoxidation and semi-pinacol rearrangement to form the spiro-oxindole center within these molecules. This work elucidates a key step in the biosynthesis of the notoamides and provides an evolutionary hypothesis regarding a common ancestor for production of enantiopure notoamides.
Collapse
|
4
|
Fraley AE, Tran HT, Kelly SP, Newmister SA, Tripathi A, Kato H, Tsukamoto S, Du L, Li S, Williams RM, Sherman DH. Cover Feature: Flavin‐Dependent Monooxygenases NotI and NotI′ Mediate Spiro‐Oxindole Formation in Biosynthesis of the Notoamides (ChemBioChem 17/2020). Chembiochem 2020. [DOI: 10.1002/cbic.202000548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
5
|
Chaabane M, Williams RM, Stephens AT, Park JW. circDeep: deep learning approach for circular RNA classification from other long non-coding RNA. Bioinformatics 2020; 36:73-80. [PMID: 31268128 PMCID: PMC6956777 DOI: 10.1093/bioinformatics/btz537] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 06/13/2019] [Accepted: 07/01/2019] [Indexed: 01/17/2023] Open
Abstract
MOTIVATION Over the past two decades, a circular form of RNA (circular RNA), produced through alternative splicing, has become the focus of scientific studies due to its major role as a microRNA (miRNA) activity modulator and its association with various diseases including cancer. Therefore, the detection of circular RNAs is vital to understanding their biogenesis and purpose. Prediction of circular RNA can be achieved in three steps: distinguishing non-coding RNAs from protein coding gene transcripts, separating short and long non-coding RNAs and predicting circular RNAs from other long non-coding RNAs (lncRNAs). However, the available tools are less than 80 percent accurate for distinguishing circular RNAs from other lncRNAs due to difficulty of classification. Therefore, the availability of a more accurate and fast machine learning method for the identification of circular RNAs, which considers the specific features of circular RNA, is essential to the development of systematic annotation. RESULTS Here we present an End-to-End deep learning framework, circDeep, to classify circular RNA from other lncRNA. circDeep fuses an RCM descriptor, ACNN-BLSTM sequence descriptor and a conservation descriptor into high level abstraction descriptors, where the shared representations across different modalities are integrated. The experiments show that circDeep is not only faster than existing tools but also performs at an unprecedented level of accuracy by achieving a 12 percent increase in accuracy over the other tools. AVAILABILITY AND IMPLEMENTATION https://github.com/UofLBioinformatics/circDeep. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
Collapse
|
6
|
Sadahiro Y, Kato H, Williams RM, Tsukamoto S. Irpexine, an Isoindolinone Alkaloid Produced by Coculture of Endophytic Fungi, Irpex lacteus and Phaeosphaeria oryzae. JOURNAL OF NATURAL PRODUCTS 2020; 83:1368-1373. [PMID: 32301614 DOI: 10.1021/acs.jnatprod.0c00047] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A new isoindolinone alkaloid, irpexine (1), was isolated as a racemate, along with a known green pigment, hypoxyxylerone (2), from the coculture of two endophytic fungi, Irpex lacteus and Phaeosphaeria oryzae. Compound 1 was found to be a newly produced metabolite of I. lacteus in the coculture with P. oryzae. Although 2 was produced in a monoculture of I. lacteus, its production was markedly enhanced by the coculture.
Collapse
|
7
|
Li S, Newmister SA, Lowell AN, Zi J, Chappell CR, Yu F, Hohlman RM, Orjala J, Williams RM, Sherman DH. Control of Stereoselectivity in Diverse Hapalindole Metabolites is Mediated by Cofactor‐Induced Combinatorial Pairing of Stig Cyclases. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201913686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
8
|
Li S, Newmister SA, Lowell AN, Zi J, Chappell CR, Yu F, Hohlman RM, Orjala J, Williams RM, Sherman DH. Control of Stereoselectivity in Diverse Hapalindole Metabolites is Mediated by Cofactor-Induced Combinatorial Pairing of Stig Cyclases. Angew Chem Int Ed Engl 2020; 59:8166-8172. [PMID: 32052896 PMCID: PMC7274885 DOI: 10.1002/anie.201913686] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Indexed: 11/07/2022]
Abstract
Stereospecific polycyclic core formation of hapalindoles and fischerindoles is controlled by Stig cyclases through a three-step cascade involving Cope rearrangement, 6-exo-trig cyclization, and a final electrophilic aromatic substitution. Reported here is a comprehensive study of all currently annotated Stig cyclases, revealing that these proteins can assemble into heteromeric complexes, induced by Ca2+ , to cooperatively control the stereochemistry of hapalindole natural products.
Collapse
|
9
|
Abstract
New structural classes of antibiotics are rare, structurally novel broad-spectrum antibiotics exceptionally so. The recently discovered baulamycins constitute a remarkable example of these highly prized compounds and, as such, have attracted considerable attention in the form of both synthetic efforts and biological studies. For the first time, we report a gram-scale preparation of the common carbon framework of the baulamycin family, as well as the total synthesis of its most potent member, baulamycin A. Our approach employs highly stereoselective, catalyst-controlled asymmetric conjugate additions to thioesters to set key stereocenters, as well as the first reported use of "dry ozonolysis" to reveal a masked carboxylic acid in the total synthesis of a natural product.
Collapse
|
10
|
Fraley AE, Caddell Haatveit K, Ye Y, Kelly SP, Newmister SA, Yu F, Williams RM, Smith JL, Houk KN, Sherman DH. Molecular Basis for Spirocycle Formation in the Paraherquamide Biosynthetic Pathway. J Am Chem Soc 2020; 142:2244-2252. [PMID: 31904957 DOI: 10.1021/jacs.9b09070] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The paraherquamides are potent anthelmintic natural products with complex heptacyclic scaffolds. One key feature of these molecules is the spiro-oxindole moiety that lends a strained three-dimensional architecture to these structures. The flavin monooxygenase PhqK was found to catalyze spirocycle formation through two parallel pathways in the biosynthesis of paraherquamides A and G. Two new paraherquamides (K and L) were isolated from a ΔphqK strain of Penicillium simplicissimum, and subsequent enzymatic reactions with these compounds generated two additional metabolites, paraherquamides M and N. Crystal structures of PhqK in complex with various substrates provided a foundation for mechanistic analyses and computational studies. While it is evident that PhqK can react with various substrates, reaction kinetics and molecular dynamics simulations indicated that the dioxepin-containing paraherquamide L is the favored substrate. Through this effort, we have elucidated a key step in the biosynthesis of the paraherquamides and provided a rationale for the selective spirocyclization of these powerful anthelmintic agents.
Collapse
|
11
|
Dan Q, Newmister SA, Klas KR, Fraley AE, McAfoos TJ, Somoza AD, Sunderhaus JD, Ye Y, Shende VV, Yu F, Sanders JN, Brown WC, Zhao L, Paton RS, Houk KN, Smith JL, Sherman DH, Williams RM. Fungal indole alkaloid biogenesis through evolution of a bifunctional reductase/Diels-Alderase. Nat Chem 2019; 11:972-980. [PMID: 31548667 PMCID: PMC6815239 DOI: 10.1038/s41557-019-0326-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 08/05/2019] [Indexed: 12/25/2022]
Abstract
Prenylated indole alkaloids such as the calmodulin-inhibitory malbrancheamides and anthelmintic paraherquamides possess great structural diversity and pharmaceutical utility. Here, we report complete elucidation of the malbrancheamide biosynthetic pathway accomplished through complementary approaches. These include a biomimetic total synthesis to access the natural alkaloid and biosynthetic intermediates in racemic form and in vitro enzymatic reconstitution to provide access to the natural antipode (+)-malbrancheamide. Reductive cleavage of an L-Pro-L-Trp dipeptide from the MalG non-ribosomal peptide synthetase (NRPS) followed by reverse prenylation and a cascade of post-NRPS reactions culminates in an intramolecular [4+2] hetero-Diels-Alder (IMDA) cyclization to furnish the bicyclo[2.2.2]diazaoctane scaffold. Enzymatic assembly of optically pure (+)-premalbrancheamide involves an unexpected zwitterionic intermediate where MalC catalyses enantioselective cycloaddition as a bifunctional NADPH-dependent reductase/Diels-Alderase. The crystal structures of substrate and product complexes together with site-directed mutagenesis and molecular dynamics simulations demonstrate how MalC and PhqE (its homologue from the paraherquamide pathway) catalyse diastereo- and enantioselective cyclization in the construction of this important class of secondary metabolites.
Collapse
|
12
|
Dan Q, Newmister SA, Klas KR, Fraley AE, Paton RS, Houk KN, Williams RM, Sherman DH, Smith JL. Evolution of a bifunctional reductase/Diels–Alderase for fungal indole alkaloid biosynthesis. Acta Crystallogr A Found Adv 2019. [DOI: 10.1107/s0108767319097599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
13
|
Kato H, Sebe M, Nagaki M, Eguchi K, Kagiyama I, Hitora Y, Frisvad JC, Williams RM, Tsukamoto S. Taichunins A-D, Norditerpenes from Aspergillus taichungensis (IBT 19404). JOURNAL OF NATURAL PRODUCTS 2019; 82:1377-1381. [PMID: 30995043 DOI: 10.1021/acs.jnatprod.8b01032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Four new norditerpenes, taichunins A-D (1-4), were isolated from the fungus Aspergillus taichungensis (IBT 19404). Compound 1 has a new carbon framework. The absolute configurations were determined by the calculated ECD spectral method. Compound 1 was cytotoxic against HeLa cells with an IC50 value of 4.5 μM, whereas 2-4 were nontoxic at 50 μM.
Collapse
|
14
|
Klas KR, Kato H, Frisvad JC, Yu F, Newmister SA, Fraley AE, Sherman DH, Tsukamoto S, Williams RM. Structural and stereochemical diversity in prenylated indole alkaloids containing the bicyclo[2.2.2]diazaoctane ring system from marine and terrestrial fungi. Nat Prod Rep 2019; 35:532-558. [PMID: 29632911 DOI: 10.1039/c7np00042a] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Covering: up to February 2017 Various fungi of the genera Aspergillus, Penicillium, and Malbranchea produce prenylated indole alkaloids possessing a bicyclo[2.2.2]diazaoctane ring system. After the discovery of distinct enantiomers of the natural alkaloids stephacidin A and notoamide B, from A. protuberus MF297-2 and A. amoenus NRRL 35660, another fungi, A. taichungensis, was found to produce their diastereomers, 6-epi-stephacidin A and versicolamide B, as major metabolites. Distinct enantiomers of stephacidin A and 6-epi-stephacidin A may be derived from a common precursor, notoamide S, by enzymes that form a bicyclo[2.2.2]diazaoctane core via a putative intramolecular hetero-Diels-Alder cycloaddition. This review provides our current understanding of the structural and stereochemical homologies and disparities of these alkaloids. Through the deployment of biomimetic syntheses, whole-genome sequencing, and biochemical studies, a unified biogenesis of both the dioxopiperazine and the monooxopiperazine families of prenylated indole alkaloids constituted of bicyclo[2.2.2]diazaoctane ring systems is presented.
Collapse
|
15
|
Newmister SA, Romminger S, Schmidt JJ, Williams RM, Smith JL, Berlinck RGS, Sherman DH. Unveiling sequential late-stage methyltransferase reactions in the meleagrin/oxaline biosynthetic pathway. Org Biomol Chem 2019; 16:6450-6459. [PMID: 30141817 DOI: 10.1039/c8ob01565a] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Antimicrobial and anti-proliferative meleagrin and oxaline are roquefortine C-derived alkaloids produced by fungi of the genus Penicillium. Tandem O-methylations complete the biosynthesis of oxaline from glandicoline B through meleagrin. Currently, little is known about the role of these methylation patterns in the bioactivity profile of meleagrin and oxaline. To establish the structural and mechanistic basis of methylation in these pathways, crystal structures were determined for two late-stage methyltransferases in the oxaline and meleagrin gene clusters from Penicillium oxalicum and Penicillium chrysogenum. The homologous enzymes OxaG and RoqN were shown to catalyze penultimate hydroxylamine O-methylation to generate meleagrin in vitro. Crystal structures of these enzymes in the presence of methyl donor S-adenosylmethionine revealed an open active site, which lacks an apparent base indicating that catalysis is driven by proximity effects. OxaC was shown to methylate meleagrin to form oxaline in vitro, the terminal pathway product. Crystal structures of OxaC in a pseudo-Michaelis complex containing sinefungin and meleagrin, and in a product complex containing S-adenosyl-homocysteine and oxaline, reveal key active site residues with His313 serving as a base that is activated by Glu369. These data provide structural insights into the enzymatic methylation of these alkaloids that include a rare hydroxylamine oxygen acceptor, and can be used to guide future efforts towards selective derivatization and structural diversification and establishing the role of methylation in bioactivity.
Collapse
|
16
|
|
17
|
Park C, Clark EM, R Williams B, Schulz E, Williams RM, Holt CL. MEANING PREDICTS DECLINES IN DEPRESSIVE SYMPTOMS BUT DOESN’T BUFFER STRESS IN A NATIONAL SAMPLE OF AFRICAN AMERICANS. Innov Aging 2018. [DOI: 10.1093/geroni/igy023.1621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
18
|
Kai A, Kato H, Sherman DH, Williams RM, Tsukamoto S. Isolation of a new indoxyl alkaloid, Amoenamide B, from Aspergillus amoenus NRRL 35600: biosynthetic implications and correction of the structure of Speramide B. Tetrahedron Lett 2018; 50:4236-4240. [PMID: 30765898 DOI: 10.1016/j.tetlet.2018.10.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
A new prenylated indoxyl alkaloid, Amoenamide B (1), was isolated from Aspergillus amoenus NRRL 35600 along with Asperochramide A (2). Although many prenylated oxyindole alkaloids, containing bicyclo[2.2.2]diazaoctane cores, have been isolated from the fungus of the genera Aspergillus and Penicillium to date, 1 is the fourth compound with the indoxyl unit containing the cores. During the structure elucidation of 1, we found that the planar structure matched to that of Speramide A (3), isolated from A. ochraceus KM007, but the reported structure of 3 was incorrect and turned out to be that of Taichunamide H (4), recently isolated from A. versicolor HDN11-84.
Collapse
|
19
|
Kato H, Kai A, Kawabata T, Sunderhaus JD, McAfoos TJ, Finefield JM, Sugimoto Y, Williams RM, Tsukamoto S. Corrigendum to “Enantioselective inhibitory abilities of enantiomers of notoamides against RANKL-induced formation of multinuclear osteoclasts” [Bioorg. Med. Chem. Lett. 27 (22) (2017) 4975–4978]. Bioorg Med Chem Lett 2018; 28:2573. [DOI: 10.1016/j.bmcl.2018.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
20
|
Sugimoto K, Sadahiro Y, Kagiyama I, Kato H, Sherman DH, Williams RM, Tsukamoto S. Corrigendum to “Isolation of amoenamide A and five antipodal prenylated alkaloids from Aspergillus amoenus NRRL 35600” [Tetrahedron Lett. 58 (2017) 2797–2800]. Tetrahedron Lett 2018. [DOI: 10.1016/j.tetlet.2018.06.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
21
|
Newmister SA, Li S, Garcia-Borràs M, Sanders JN, Yang S, Lowell AN, Yu F, Smith JL, Williams RM, Houk KN, Sherman DH. Structural basis of the Cope rearrangement and cyclization in hapalindole biogenesis. Nat Chem Biol 2018; 14:345-351. [PMID: 29531360 PMCID: PMC5880276 DOI: 10.1038/s41589-018-0003-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 01/17/2018] [Indexed: 11/09/2022]
Abstract
Hapalindole alkaloids are a structurally diverse class of cyanobacterial natural products defined by their varied polycyclic ring systems and diverse biological activities. These complex metabolites are generated from a common biosynthetic intermediate by the Stig cyclases in three mechanistic steps: a rare Cope rearrangement, 6-exo-trig cyclization, and electrophilic aromatic substitution. Here we report the structure of HpiC1, a Stig cyclase that catalyzes the formation of 12-epi-hapalindole U in vitro. The 1.5-Å structure revealed a dimeric assembly with two calcium ions per monomer and with the active sites located at the distal ends of the protein dimer. Mutational analysis and computational methods uncovered key residues for an acid-catalyzed [3,3]-sigmatropic rearrangement, as well as specific determinants that control the position of terminal electrophilic aromatic substitution, leading to a switch from hapalindole to fischerindole alkaloids.
Collapse
|
22
|
Gollins S, Massalha S, Mullard A, Williams RM, Lloyd A, Morris J, Garcia-Alonso A. A Prospective Phase I/II Study of Docetaxel, Cisplatin and Continuous Capecitabine in Advanced Oesophago-Gastric Cancer (NWCOG-3). Clin Oncol (R Coll Radiol) 2018; 30:409-417. [PMID: 29573846 DOI: 10.1016/j.clon.2018.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 01/24/2018] [Indexed: 10/17/2022]
Abstract
AIMS This open-label prospective phase I/II dose-escalation study determined the maximum tolerated dose (MTD) and then evaluated response, safety and feasibility of a novel combination of docetaxel, cisplatinum and capecitabine (DCC) in chemotherapy-naive patients with advanced oesophago-gastric carcinoma. MATERIALS AND METHODS Patients with adenocarcinoma or squamous cell carcinoma of the oesophagus or stomach, of good performance status, deemed too advanced for curative treatment, were given systematically increasing doses of 3 weekly DCC to ascertain the MTD. Phase II administered up to six cycles of DCC at the MTD, assessing response and toxicity. RESULTS Between November 2007 and November 2012, 15 patients were recruited into phase I and 41 into phase II. The MDT was a 21 day cycle of docetaxel 60 mg/m2 IV day 1, cisplatinum 60 mg/m2 IV day 1 and oral capecitabine 1000 mg/m2 daily in two divided doses for days 1-21. The most common phase II grade 3-4 toxicities were neutropenia 88% (10% febrile neutropenia), fatigue 15%, sensory neuropathy 10% and non-neutropenic infection 10%. The overall response rate was 51%, median progression-free survival was 7.4 months (confidence interval 6.7-9.4) and median overall survival was 10.9 months (confidence interval 7.7-13.7). CONCLUSION DCC was tolerable and feasible with promising efficacy, and may be suitable for future investigation in both first-line metastatic and neoadjuvant settings.
Collapse
|
23
|
Goodfellow A, Calvert H, Williams RM. Angiokeratoma Corporis Diffusum without Impairment of Renal Function. J R Soc Med 2018; 73:373-5. [PMID: 6787196 PMCID: PMC1437491 DOI: 10.1177/014107688007300516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
24
|
Kato H, Nakahara T, Sugimoto K, Matsuo K, Kagiyama I, Frisvad JC, Sherman DH, Williams RM, Tsukamoto S. Correction to "Isolation of Notoamide S and Enantiomeric 6-epi-Stephacidin A from the Terrestrial Fungus Aspergillus amoenus: Biogenetic Implications". Org Lett 2017; 20:315. [PMID: 29235872 DOI: 10.1021/acs.orglett.7b03781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
25
|
Fraley AE, Garcia-Borràs M, Tripathi A, Khare D, Mercado-Marin EV, Tran H, Dan Q, Webb GP, Watts KR, Crews P, Sarpong R, Williams RM, Smith JL, Houk KN, Sherman DH. Function and Structure of MalA/MalA', Iterative Halogenases for Late-Stage C-H Functionalization of Indole Alkaloids. J Am Chem Soc 2017; 139:12060-12068. [PMID: 28777910 PMCID: PMC5595095 DOI: 10.1021/jacs.7b06773] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Malbrancheamide is a dichlorinated fungal indole alkaloid isolated from both Malbranchea aurantiaca and Malbranchea graminicola that belongs to a family of natural products containing a characteristic bicyclo[2.2.2]diazaoctane core. The introduction of chlorine atoms on the indole ring of malbrancheamide differentiates it from other members of this family and contributes significantly to its biological activity. In this study, we characterized the two flavin-dependent halogenases involved in the late-stage halogenation of malbrancheamide in two different fungal strains. MalA and MalA' catalyze the iterative dichlorination and monobromination of the free substrate premalbrancheamide as the final steps in the malbrancheamide biosynthetic pathway. Two unnatural bromo-chloro-malbrancheamide analogues were generated through MalA-mediated chemoenzymatic synthesis. Structural analysis and computational studies of MalA' in complex with three substrates revealed that the enzyme represents a new class of zinc-binding flavin-dependent halogenases and provides new insights into a potentially unique reaction mechanism.
Collapse
|