Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FLBackground: [BAL27862][1] is a novel small molecule, inducing apoptosis in cancer cells through microtubule destabilization. A series of amino acid-derived [BAL27862][1] prodrugs was evaluated for solubility and in vivo conversion into drug. The Lys-prodrug BAL101553 was further compared with [BAL27862][1] in animal models of human cancer.Methods: Kinetic solubility of compounds was determined by diluting DMSO stock solutions with aqueous buffer. Pharmacokinetics and prodrug conversion were evaluated in mice. In vivo efficacy was analyzed in colon carcinoma SW480 and patient-derived mammary MaCa4151 xenografts. MTD dosing was used in all cases, adapted for each mouse strain.Results: All amino acid-derived prodrugs showed significantly increased aqueous solubility compared to [BAL27862][1], most pronounced at pH 3. At pH 5 and 6.5, the dibasic Lys-prodrug BAL101553 proved to be the most soluble compound (>200 μM). In vivo conversion rates differed significantly between the prodrugs. Highest exposure to the parent drug was obtained with the Lys, Ala and Gly derivatives, whereas the exposure achieved with other amino acid prodrugs (e.g. Phe, Asn, Ser, Trp) was more than twofold lower. Combining high solubility, good conversion and oral bioavailability, BAL101553 was selected for further evaluation. In tumor models, [BAL27862][1] was rapidly distributed into SW480 tumors after i.v. administration of drug or BAL101553. Strikingly, [BAL27862][1] was retained in tumor ∼1.5 times longer after BAL101553 (T1/2: 8.3h) vs. [BAL27862][1] (T1/2: 5.4h) administration. In all models, a higher MTD was reached with the prodrug, related to ∼60% prodrug conversion in vivo. In MaCa4151 xenografts, twice-weekly i.v. administration of BAL101553 (17 mg/kg [BAL27862][1] equivalents [BE]) elicited superior antitumor effects (final T/C=30%; p<0.05 vs. controls) as compared to [BAL27862][1] (10 mg/kg; T/C=66%). Once-weekly dosing of BAL101553 (14 mg/kg BE) and [BAL27862][1] (8 mg/kg) in the SW480 model resulted in final T/C's of 34% and 49% (both p<0.001), resp. Strikingly, fractionation of the same total weekly dose did not significantly affect outcome for either BAL101553 (3x per day once-weekly: T/C=40%; 3x per week: T/C=26%; both p<0.001) or [BAL27862][1] (3x per day once-weekly: T/C=54%; 3x per week: T/C=54%; p=0.001 and p=0.002, resp.), suggesting antitumor response is related to AUC. Again, indications of superior antitumor responses were observed with all prodrug schedules in this model.Conclusions: BAL101553 has been identified as a highly soluble prodrug of [BAL27862][1], which can be administered p.o. or i.v. in the absence of solubilizing excipients known to be associated with adverse side-effects. Its administration facilitates higher tumor exposure to the active agent, with more profound responses in some tumor models. These data, together with a flexible dosing potential, support profiling of BAL101553 in cancer patients.Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1347. doi:10.1158/1538-7445.AM2011-1347 [1]: /lookup/external-ref?link_type=GENPEPT&access_num=BAL27862&atom=%2Fcanres%2F71%2F8_Supplement%2F1347.atom

The Ewing sarcoma family of tumors or Ewing sarcoma (ES) is the second most common malignant bone tumor of childhood. The prognosis for localized Ewing sarcoma has improved through the development of intense multimodal therapy over the past several decades. Unfortunately, patients with recurrent or metastatic disease continue to have a poor prognosis. Therefore, a number of complementary approaches are being developed in both the preclinical and clinical arenas to improve these outcomes. In this review, we will discuss efforts to directly target the biologic drivers of this disease and relate these efforts to the experience with several different agents both in the clinic and under development. We will review the data for compounds that have shown excellent activity in the clinic, such as the camptothecins, and summarize the biological data that supports this activity. In addition, we will review the clinical experience with IGF1 targeted agents, ET-743 and epigenetically targeted therapies, the substantial amount of literature that supports their activity in Ewing sarcoma and the challenges remaining translating these therapies to the clinic. Finally, we will highlight recent work aimed at directly targeting the EWS–FLI1 transcription factor with small molecules in Ewing tumors.

The pseudopeptide pyrrolidinedione antibiotics, such as moiramide B, have recently been discovered to target the multisubunit acetyl coenzyme A (acetyl-CoA) carboxylases of bacteria. In this paper, we describe synthetic variations of each moiety of the modularly composed pyrrolidinediones, providing insight into structure-activity relationships of biochemical target activity, in vitro potency, and in vivo efficacy. The novel derivatives showed highly improved activities against gram-positive bacteria compared to those of previously reported variants. The compounds exhibited a MIC(90) value of 0.1 microg/ml against a broad spectrum of Staphylococcus aureus clinical isolates. No cross-resistance to antibiotics currently used in clinical practice was observed. Resistance mutations induced by pyrrolidinediones are exclusively located in the carboxyltransferase subunits of the bacterial acetyl-CoA carboxylase, indicating the identical mechanisms of action of all derivatives tested. Improvement of the physicochemical profile was achieved by salt formation, leading to aqueous solubilities of up to 5 g/liter. For the first time, the in vitro activity of this compound class was compared with its in vivo efficacy, demonstrating a path from compounds weakly active in vivo to agents with significant efficacy. In a murine model of S. aureus sepsis, the 100% effective dose of the best compound reported was 25 mg/kg of body weight, only fourfold higher than that of the comparator molecule linezolid. The obvious improvements achieved by chemical derivatization reflect the potential of this novel antibiotic compound class for future therapy.

Despite recent progress in antithrombotic therapy, there is still an unmet medical need for safe and orally available anticoagulants. The coagulation enzyme Factor Xa (FXa) is a particularly promising target, and recent efforts in this field have focused on the identification of small-molecule inhibitors with good oral bioavailability. We identified oxazolidinone derivatives as a new class of potent FXa inhibitors. Lead optimization led to the discovery of BAY 59-7939 (5), a highly potent and selective, direct FXa inhibitor with excellent in vivo antithrombotic activity. The X-ray crystal structure of 5 in complex with human FXa clarified the binding mode and the stringent requirements for high affinity. The interaction of the neutral ligand chlorothiophene in the S1 subsite allows for the combination of good oral bioavailability and high potency for nonbasic 5. Compound 5 is currently under clinical development for the prevention and treatment of thromboembolic diseases.

BAY 59-7939 is an oral, direct Factor Xa (FXa) inhibitor in development for the prevention and treatment of arterial and venous thrombosis. BAY 59-7939 competitively inhibits human FXa (K(i) 0.4 nm) with > 10 000-fold greater selectivity than for other serine proteases; it also inhibited prothrombinase activity (IC(50) 2.1 nm). BAY 59-7939 inhibited endogenous FXa more potently in human and rabbit plasma (IC(50) 21 nm) than rat plasma (IC(50) 290 nm). It demonstrated anticoagulant effects in human plasma, doubling prothrombin time (PT) and activated partial thromboplastin time at 0.23 and 0.69 microm, respectively. In vivo, BAY 59-7939 reduced venous thrombosis (fibrin-rich, platelet-poor thrombi) dose dependently (ED(50) 0.1 mg kg(-1) i.v.) in a rat venous stasis model. BAY 59-7939 reduced arterial (fibrin- and platelet-rich) thrombus formation in an arteriovenous (AV) shunt in rats (ED(50) 5.0 mg kg(-1) p.o.) and rabbits (ED(50) 0.6 mg kg(-1) p.o.). Slight inhibition of FXa (32% at ED(50)) reduced thrombus formation in the venous model; to affect arterial thrombosis in the rat and rabbit, stronger inhibition of FXa (74%, 92% at ED(50)) was required. Calculated plasma levels in rabbits at the ED(50) were 14-fold lower than in the rat AV shunt model, correlating with the 14-fold lower IC(50) of FXa inhibition in rabbit compared with rat plasma; this may suggest a correlation between FXa inhibition and antithrombotic activity. Bleeding times in rats and rabbits were not significantly affected at antithrombotic doses (3 mg kg(-1) p.o., AV shunt). Based on these results, BAY 59-7939 was selected for clinical development.

The pseudopeptide pyrrolidinedione natural products moiramide B and andrimid represent a new class of antibiotics that target bacterial fatty acid biosynthesis. Structure activity relationship (SAR) studies revealed a high degree of variability for the fatty acid side chain, allowing optimization of physicochemical parameters, and a restricted SAR for the pyrrolidinedione group, indicating major relevance of this subunit for efficient target binding. (C) 2004 Elsevier Ltd. All rights reserved.

Increasing rates of bacterial resistance to known classes of antibiotics present a severe global challenge. As a consequence, the search for new chemical entities that adress novel bacterial targets continues. Aminoacyl-tRNA synthetases are essential enzymes for protein biosynthesis that have emerged as an interesting target class in antibacterial research. The value of this target class is exemplified in this review by the progress achieved with inhibitors of bacterial phenylalanyl-tRNA synthelase (phenylatanine-tRNA ligase) as potential antibacterial agents.

ABSTRACT Phenylalanyl (Phe)-tRNA synthetase (Phe-RS) is an essential enzyme which catalyzes the transfer of phenylalanine to the Phe-specific transfer RNA (tRNA Phe ), a key step in protein biosynthesis. Phenyl-thiazolylurea-sulfonamides were identified as a novel class of potent inhibitors of bacterial Phe-RS by high-throughput screening and chemical variation of the screening hit. The compounds inhibit Phe-RS of Escherichia coli , Haemophilus influenzae , Streptococcus pneumoniae , and Staphylococcus aureus , with 50% inhibitory concentrations in the nanomolar range. Enzyme kinetic measurements demonstrated that the compounds bind competitively with respect to the natural substrate Phe. All derivatives are highly selective for the bacterial Phe-RS versus the corresponding mammalian cytoplasmic and human mitochondrial enzymes. Phenyl-thiazolylurea-sulfonamides displayed good in vitro activity against Staphylococcus , Streptococcus , Haemophilus , and Moraxella strains, reaching MICs below 1 μg/ml. The antibacterial activity was partly antagonized by increasing concentrations of Phe in the culture broth in accordance with the competitive binding mode. Further evidence that inhibition of tRNA Phe charging is the antibacterial principle of this compound class was obtained by proteome analysis of Bacillus subtilis . Here, the phenyl-thiazolylurea-sulfonamides induced a protein pattern indicative of the stringent response. In addition, an E. coli strain carrying a relA mutation and defective in stringent response was more susceptible than its isogenic relA + parent strain. In vivo efficacy was investigated in a murine S. aureus sepsis model and a S. pneumoniae sepsis model in rats. Treatment with the phenyl-thiazolylurea-sulfonamides reduced the bacterial titer in various organs by up to 3 log units, supporting the potential value of Phe-RS as a target in antibacterial therapy.

Increasing rates of bacterial resistance to known classes of antibiotics present a severe global challenge. As a consequence, the search for new chemical entities that address novel bacterial targets remains ongoing. Aminoacyl-tRNA synthetases (aa-RS) are essential enzymes for protein biosynthesis and emerged as an interesting target class in antibacterial research. These enzymes are present in all living organisms, and they are indispensable for the highly specific translation of the messenger-RNA (mRNA) template into protein via specific transfer-RNAs (tRNAs) as adapter molecules. When one aa-RS is inhibited, the corresponding tRNA is not charged and is therefore unavailable for translation. This leads to protein synthesis inhibition, which, in turn, causes cell growth arrest. Consequently, each compound that inhibits any of the aa-RS is a potential antibacterial agent. The clinical utility of this principle is proven by the natural product Ile-RS inhibitor pseudomonic acid, which is currently marketed as an antibacterial agent for topical application. Various chemical structures that inhibit aa-RS have been identified. These inhibitors have either been isolated from natural sources or have been generated synthetically. The synthetic inhibitors are modifications of natural inhibitors, derivatives of the natural synthetase substrates and reaction intermediates, or have been identified by screening of compound libraries. The recent progress achieved with these different classes of aa-RS inhibitors and their antibacterial potential in vitro and in vivo is discussed in this review.

The multisubunit acetyl-CoA carboxylase, which catalyzes the first committed step in fatty acid biosynthesis, is broadly conserved among bacteria. Its rate-limiting role in formation of fatty acids makes this enzyme an attractive target for the design of novel broad-spectrum antibacterials. However, no potent inhibitors have been discovered so far. This report describes the identification and characterization of highly potent bacterial acetyl-CoA carboxylase inhibitors with antibacterial activity for the first time. We demonstrate that pseudopeptide pyrrolidine dione antibiotics such as moiramide B inhibit the Escherichia coli enzyme at nanomolar concentrations. Moiramide B targets the carboxyltransferase reaction of this enzyme with a competitive inhibition pattern versus malonyl-CoA (Ki value=5 nm). Inhibition at nanomolar concentrations of the pyrrolidine diones is also demonstrated using recombinantly expressed carboxyltransferases from other bacterial species (Staphylococcus aureus, Streptococcus pneumoniae, and Pseudomonas aeruginosa). We isolated pyrrolidine dione-resistant strains of E. coli, S. aureus, and Bacillus subtilis, which contain mutations within the carboxyltransferase subunits AccA or AccD. We demonstrate that such mutations confer resistance to pyrrolidine diones. Inhibition values (IC50) of >100 μm regarding an eukaryotic acetyl-CoA carboxylase from rat liver indicate high selectivity of pyrrolidine diones for the bacterial multisubunit enzyme. The natural product moiramide B and synthetic analogues show broad-spectrum antibacterial activity. The knowledge of the target and the availability of facile assays using carboxyltransferases from different pathogens will enable evaluation of the antibacterial potential of the pyrrolidine diones as a promising antibacterial compound class acting via a novel mode of action.

Combinaciones que contienen A) al menos un compuesto de formula (I) **(Ver formula)** en la que R1representa 2-tiofeno que esta sustituido en la posicion 5 con un resto del grupo de cloro, bromo, metilo o trifluorometilo; R2 representa DA-: en la que el resto "A" representa fenileno; el resto "D" representa un heterociclo saturado de 5 o 6 miembros, que esta unido por un atomo de nitrogeno con "A", que posee un grupo carbonilo en directa vecindad con el atomo de nitrogeno de union y en que un miembro de carbono de anillo puede estar sustituido por un heteroatomo del grupo de S, N y O; en la que el grupo "A" anteriormente definido puede estar eventualmente sustituido en posicion meta respecto a la union con oxazolidinona una o dos veces con un resto del grupo de fluor, cloro, nitro, amino, trifluorometilo, metilo o ciano, R3, R4, R5, R6, R7 y R8 representan hidrogeno, sus sales, hidratos, profarmacos farmaceuticamente compatible o sus mezclas y B) cerivastatina (Rivastatin, Baycol), lovastatina (Mevacor), simvastatina (Zocor), pravastatina (Pravachol), fluvastatina (Lescol), atorvastatina (Lipitor), captopril, lisinopril, enalapril, ramipril, cilazapril, benazepril, fosinopril, quinapril, perindopril, embusartan, losartan, valsartan, irbesartan, candesartan, eprosartan, temisartan, carvedilol, alprenolol, bisoprolol, acebutolol, atenolol, betaxolol, carteolol, metoprolol, nadolol, penbutolol, pindolol, propanolol, timolol, prazosina, bunazosina, doxazosina, terazosina, hidroclorotiazida, furosemida, bumetanida, piretanida, torasemida, amilorid, dihidrala zina, verapamilo, diltiazem, nifedipina (Adalat), nitrendipina (Bayotensin), 5-mononitrato de isosorbida, dinitrato de isosorbida, binitrato de glicerol, activador de plasminogeno de tejido (t-PA), estreptocinasa, reteplasa, urocinasa, heparina (UFH), tinzaparina, certoparina, parnaparina, nadioparina, ardeparina, enoxaparina, reviparina, dalteparina, hirudina, aspirina, ticlopidina (Ticlid), clopidogrel (Plavix), abciximab, epifibatida, tirofiban, lamifiban o lefradafiban.