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Primary myelofibrosis (PMF) is a chronic myeloproliferative neoplasm (MPN) that usually portends a poor prognosis with limited therapeutic options available. Currently only allogeneic stem cell transplantation is curative in those who are candidates, while administration of the JAK1/2 inhibitor ruxolitonib carries a risk of worsening cytopenia. The limited therapeutic options available highlight the need for the development of novel treatments for PMF. Lysyl oxidase (LOX), an enzyme vital for collagen cross-linking and extracellular matrix stiffening, has been found to be up-regulated in PMF. Herein, we evaluate two novel LOX inhibitors, PXS-LOX_1 and PXS-LOX_2, in two animal models of PMF (GATA1low and JAK2V617F-mutated mice). Specifically, PXS-LOX_1 or vehicle was given to 15-16-week-old GATA1low mice via intraperitoneal injection at a dose of 15 mg/kg four times a week for nine weeks. PXS-LOX_1 was found to significantly decrease the bone marrow fibrotic burden and megakaryocyte number compared to vehicle in both male and female GATA1low mice. Given these results, PXS-LOX_1 was then tested in 15-17-week-old JAK2V617F-mutated mice at a dose of 30 mg/kg four times a week for eight weeks. Again, we observed a significant decrease in bone marrow fibrotic burden. PXS-LOX_2, a LOX inhibitor with improved oral bioavailability, was next evaluated in 15 to 17-week-old JAK2V617F-mutated mice at a dose of 5 mg/kg p.o. four times a week for eight weeks. This inhibitor also resulted in a significant decrease in bone marrow fibrosis, albeit with a more pronounced amelioration in female mice. Taking these results together, PXS-LOX_1 and PXS-LOX_2 appear to be promising new candidates for the treatment of fibrosis in PMF.

The discovery of a dual MAO-B/SSAO inhibitor PXS-5131 is reported. The compound offers a compact and rigid three-dimensional structure with superior selectivity over MAO-A. Potency and selectivity are linked to both the double bond geometry and stereochemistry of the allylamine moiety, highlighting the importance of optimal set up of these features in the class of amine oxidase inhibitors. PXS-5131 possesses an attractive preclinical pharmacokinetic profile and has anti-inflammatory properties in models of acute inflammation and neuroinflammation.

The hallmark of fibrosis is the accumulation of excessive collagen in tissue as a result of an imbalance between collagen formation and degradation. A key step in collagen formation is its stabilization – and with this, slowing of its degradation – by cross-links. This cross-linking is mediated by lysyl oxidases, a group of five related enzymes consisting of lysyloxidase (LOX) and lysyl oxidase like 1–4 (LOXL1–4), of which LOXL2 is thought to be of particular relevance in most conditions of pathological fibrosis. Recently, the first inhibitors of LOXL2 enzyme activity and dual inhibitors of LOXL2 and LOXL3 have been advanced into clinical studies. The data underlying their promise as novel anti-fibrotic therapeutics is summarised, together with an outlook on the potential of inhibition of other members of this family of enzymes.

Lysyl oxidase-like 2 (LOXL2) is a secreted enzyme that catalyzes the formation of cross-links in extracellular matrix proteins, namely, collagen and elastin, and is indicated in fibrotic diseases. Herein, we report the identification and subsequent optimization of a series of indole-based fluoroallylamine inhibitors of LOXL2. The result of this medicinal chemistry campaign is PXS-5120A (12k), a potent, irreversible inhibitor that is >300-fold selective for LOXL2 over LOX. PXS-5120A also shows potent inhibition of LOXL3, an emerging therapeutic target for lung fibrosis. Key to the development of this compound was the utilization of a compound oxidation assay. PXS-5120A was optimized to show negligible substrate activity in vitro for related amine oxidase family members, leading to metabolic stability. PXS-5120A, in a pro-drug form (PXS-5129A, 12o), displayed anti-fibrotic activity in models of liver and lung fibrosis, thus confirming LOXL2 as an important target in diseases where collagen cross-linking is implicated.

Fibrosis is characterized by the excessive deposition of extracellular matrix and crosslinked proteins, in particular collagen and elastin, leading to tissue stiffening and disrupted organ function. Lysyl oxidases are key players during this process, as they initiate collagen crosslinking through the oxidation of the ε‐amino group of lysine or hydroxylysine on collagen side‐chains, which subsequently dimerize to form immature, or trimerize to form mature, collagen crosslinks. The role of LOXL2 in fibrosis and cancer is well documented, however the specific enzymatic function of LOXL2 and LOXL3 during disease is less clear. Herein, we describe the development of PXS‐5153A, a novel mechanism based, fast‐acting, dual LOXL2/LOXL3 inhibitor, which was used to interrogate the role of these enzymes in models of collagen crosslinking and fibrosis. PXS‐5153A dose‐dependently reduced LOXL2‐mediated collagen oxidation and collagen crosslinking in vitro. In two liver fibrosis models, carbon tetrachloride or streptozotocin/high fat diet‐induced, PXS‐5153A reduced disease severity and improved liver function by diminishing collagen content and collagen crosslinks. In myocardial infarction, PXS‐5153A improved cardiac output. Taken together these results demonstrate that, due to their crucial role in collagen crosslinking, inhibition of the enzymatic activities of LOXL2/LOXL3 represents an innovative therapeutic approach for the treatment of fibrosis.

The synthesis of the structure, 1, assigned to the anti-inflammatory natural product myrsinoic acid F is reported together with a means for preparing its Z-isomer 21. While neither of these compounds corresponds to the natural product, both of them are anti-inflammatory agents (as determined using a mouse ear edema assay) with congener 1 being notably more potent than the widely prescribed NSAID indometacin.

// Joan Chang 1 , Morghan C. Lucas 2 , Lidia E. Leonte 1 , Marc Garcia-Montolio 1 , Lukram Babloo Singh 1 , Alison D. Findlay 3 , Mandar Deodhar 3 , Jonathan S. Foot 3 , Wolfgang Jarolimek 3 , Paul Timpson 2 , Janine T. Erler 1 , Thomas R. Cox 1, 2 1 Biotech Research and Innovation Centre (BRIC), University of Copenhagen (UCPH), Copenhagen, Denmark 2 The Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Cancer Division, St Vincent’s Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia 3 Pharmaxis Pharmaceutical Ltd., Frenchs Forest, Australia Correspondence to: Thomas R. Cox, email: t.cox@garvan.org.au Janine T. Erler, email: janine.erler@bric.ku.dk Keywords: lysyl oxidase-like 2, lysyl oxidase, breast cancer, metastasis Received: August 26, 2016 Accepted: January 17, 2017 Published: February 10, 2017 ABSTRACT Lysyl Oxidase-like 2 (LOXL2), a member of the lysyl oxidase family of amine oxidases is known to be important in normal tissue development and homeostasis, as well as the onset and progression of solid tumors. Here we tested the anti-tumor properties of two generations of novel small molecule LOXL2 inhibitor in the MDA-MB-231 human model of breast cancer. We confirmed a functional role for LOXL2 activity in the progression of primary breast cancer. Inhibition of LOXL2 activity inhibited the growth of primary tumors and reduced primary tumor angiogenesis. Dual inhibition of LOXL2 and LOX showed a greater effect and also led to a lower overall metastatic burden in the lung and liver. Our data provides the first evidence to support a role for LOXL2 specific small molecule inhibitors as a potential therapy in breast cancer.

A stereocontrolled total synthesis of the cytotoxic spiroacetal-containing polyketide (−)-spirangien A is described. This utilizes an aldol-based strategy to construct a common stereotetrad intermediate that was elaborated into the spiroacetal core, followed by the introduction of the unstable pentaene-containing side chain, performed with exclusion of light, using sequential Stille cross-coupling reactions. An expedient first total synthesis of (−)-spirangien A, a potent cytotoxic and antifungal polyketide of myxobacterial origin, is described. By using a common 1,3-diol intermediate obtained by an efficient aldol-reduction sequence for installation of the C15–C18 and C25–C28 stereotetrads and a reagent-controlled boron aldol coupling followed by spiroacetalization, a highly convergent strategy was developed for construction of the elaborate spiroacetal core. Conversion of this advanced spiroacetal intermediate into (+)-spirangien diene, obtained previously by controlled degradation of spirangien A, was then achieved by installation of the truncated side-chain using an allylboration–Peterson sequence. The total synthesis of (−)-spirangien A was then achieved by the controlled attachment of the unsaturated C1–C12 side-chain, avoiding exposure to light. A Stork–Wittig olefination and double Stille cross-coupling sequence was exploited to install the delicate conjugated pentaene chromophore featuring alternating (Z)- and (E)-olefins, leading initially to the methyl ester of spirangien A, which proved significantly more stable than the corresponding free acid. Subsequent careful hydrolysis afforded (−)-spirangien A, validating the relative and absolute configuration.

Synthetic studies pertaining to a novel class of structurally related glycosidic 14-membered macrolides of marine origin are reported. The evolution of a versatile aldol-based strategy that culminated in the total syntheses of callipeltoside A and aurisides A and B is detailed. Using a combination of biogenetic considerations and conformational analysis, a revised stereochemical assignment for the related polyketide dolastatin 19 was proposed and validated by total synthesis.

[reaction: see text] A revised configurational assignment for the cytotoxic marine macrolide dolastatin 19 is proposed and validated by total synthesis. Key features of the route include an asymmetric vinylogous aldol reaction to install the isolated C13 stereocenter and (E)-trisubstituted alkene, two sequential 1,4-syn boron-mediated aldol reactions, and a Mukaiyama glycosylation to append the l-rhamnose-derived pyranoside.

Operationally simple Au(I)-catalyzed intramolecular hydroarylation (IMHA) reactions of terminal alkynes that proceed in high yield and under very mild conditions are described. These processes involve low catalyst loadings, mild reaction temperatures, and short reaction times, require no cocatalysts or additives, and allow for the generation of a number of important heterocyclic motifs from readily accessible starting materials.

Semicarbazide-sensitive amine oxidase (SSAO), also known as vascular adhesion protein-1 (VAP-1), is a member of the copper-dependent amine oxidase family that is associated with various forms of inflammation and fibrosis. To investigate the therapeutic potential of SSAO/VAP-1 inhibition, potent and selective inhibitors with drug-like properties are required. PXS-4681A [(Z)-4-(2-(aminomethyl)-3-fluoroallyloxy)benzenesulfonamide hydrochloride] is a mechanism-based inhibitor of enzyme function with a pharmacokinetic and pharmacodynamic profile that ensures complete, long-lasting inhibition of the enzyme after a single low dose in vivo. PXS-4681A irreversibly inhibits the enzyme with an apparent Ki of 37 nM and a kinact of 0.26 min(-1) with no observed turnover in vitro. It is highly selective for SSAO/VAP-1 when profiled against related amine oxidases, ion channels, and seven-transmembrane domain receptors, and is superior to previously reported inhibitors. In mouse models of lung inflammation and localized inflammation, dosing of this molecule at 2 mg/kg attenuates neutrophil migration, tumor necrosis factor-α, and interleukin-6 levels. These results demonstrate the drug-like properties of PXS-4681A and its potential use in the treatment of inflammation.

Operationally simple Au(I)-catalyzed intramolecular hydroarylation (IMHA) reactions of terminal alkynes that proceed in high yield and under very mild conditions are described. These processes involve low catalyst loadings, mild reaction temperatures, and short reaction times, require no cocatalysts or additives, and allow for the generation of a number of important heterocyclic motifs from readily accessible starting materials.

A growing number of complex polyketides, isolated from a variety of marine and terrestrial sources, present novel scaffolds for the development of cancer therapeutic agents. However, the low natural abundance of such lead compounds often precludes full biological evaluation, which demands the development of efficient synthetic routes to afford a sustainable supply. In this account, we provide an overview of the total synthesis of several representative anticancer polyketides – dolastatin 19, spirangien A, reidispongiolide A, and spongistatin 1/altohyrtin A – based on versatile aldol methodology developed in our group.

The first total synthesis of (−)-spirangien A, a cytotoxic and antifungal polyketide of myxobacterial origin, is reported; this exploits a Stork–Wittig olefination and double Stille cross-coupling sequence to install the sensitive pentaene side chain onto a fully elaborated spiroacetal core, leading initially to the methylester of spirangien A.

Synthetic studies pertaining to a novel class of structurally related glycosidic 14-membered macrolides of marine origin are reported. The evolution of a versatile aldol- based strategy that culminated in the total syntheses of callipeltoside A and aurisides A and B is detailed. Using a combination of biogenetic considerations and conformational analysis, a revised stereochemical assignment for the related polyketide dolastatin 19 was proposed and validated by total synthesis.

A convergent synthesis of pteridic acids A and B, epimeric spiroacetal polyketides with potent plant growth promoter properties, is described. The use of boron aldol methodology efficiently achieved the stereocontrolled construction of advanced C1–C11 and C12–C16 subunits, which were coupled to generate a linear (Z)-enone precursor that underwent spiroacetalization with HF·pyridine, providing pteridic acids A and B after saponification.

Using conformational analysis and biogenetic considerations, a revised configurational assignment for the cytotoxic marine macrolide dolastatin 19 is proposed, together with its validation by completion of the first total synthesis. Key features of the highly stereocontrolled route include an asymmetric vinylogous Mukaiyama aldol reaction to simultaneously install both the remote C13 stereocenter and the C10–C11 ( E )-trisubstituted olefin, two sequential 1,4- syn boron-mediated aldol reactions, and a late-stage, α-selective Mukaiyama glycosylation to append the l -rhamnose-derived pyranoside.

A seven-step reaction sequence has been used to convert the enantiomerically pure cis-1,2-dihydrocatechol 10 into the cyclohexenone 17a. A near equivalent sequence involving the same starting material has allowed for the synthesis of the regioisomeric system 17b. Compound 17a is related to the A-ring of ent-viridin (ent-1), the non-natural enantiomer of the furanosteroid viridin (1).

The first total synthesis of (-)-spirangien A, a cytotoxic and antifungal polyketide of myxobacterial origin, is reported; this exploits a Stork-Wittig olefination and double Stille cross-coupling sequence to install the sensitive pentaene side chain onto a fully elaborated spiroacetal core, leading initially to the methyl ester of spirangien A.

© 2015 The Authors. Idiopathic pulmonary fibrosis (IPF) is a chronic disease characterised by a progressive decline in lung function which can be attributed to excessive scarring, inflammation and airway remodelling. Mannose-6-phosphate (M6P) is a strong inhibitor of fibrosis and its administration has been associated with beneficial effects in tendon repair surgery as well as nerve repair after injury. Given this promising therapeutic approach we developed an improved analogue of M6P, namely PXS64, and explored its anti-fibrotic effects in vitro. Normal human lung fibroblasts (NHLF) and human lung fibroblast 19 cells (HF19) were exposed to active recombinant human TGF-β1 to induce increases in fibrotic markers. rhTGF-β1 increased constitutive protein levels of fibronectin and collagen in the NHLF cells, whereas HF19 cells showed increased levels of fibronectin, collagen as well as αSMA (alpha smooth muscle actin). PXS64 demonstrated a robust inhibitory effect on all proteins analysed. IPF patient fibroblasts treated with PXS64 presented an improved phenotype in terms of their morphological appearance, as well as a decrease in fibrotic markers (collagen, CTGF, TGF-β3, tenascin C, αSMA and THBS1). To explore the cell signalling pathways involved in the anti-fibrotic effects of PXS64, proteomics analysis with iTRAQ labelling was performed and the data demonstrated a specific antagonistic effect on the TGF-β1 pathway. This study shows that PXS64 effectively inhibits the production of extracellular matrix, as well as myofibroblast differentiation during fibrosis. These results suggest that PXS64 influences tissue remodelling by inhibiting TGF-β1 signalling in NHLF and HF19 cell lines, as well as in IPF patient fibroblasts. Thus PXS64 is a potential candidate for preclinical application in pulmonary fibrosis.