Discovery of Potent, Selective Triazolothiadiazole-Containing c-Met Inhibitors.

Herein, we report a novel series of highly potent and selective triazolothiadiazole c-Met inhibitors. Starting with molecule 5, we have applied structure-based drug design principles to identify the triazolothiadiazole ring system. We successfully replaced the metabolically unstable phenolic moiety with a quinoline group. Further optimization around the 5,6 bicyclic moiety led to the identification of 21. Compound 21 suffered from PDE3 selectivity issues and subsequent, structurally informed design led to the discovery of compound 23. Compound 23 has exquisite kinase selectivity, excellent potency, favorable ADME profile, and showed dose-dependent antitumor efficacy in a SNU-5 gastric cancer xenograft model.

Correction: Pancreatic Cancer: Feasibility and Outcome After Radiochemotherapy with High Dose External Radiotherapy for Non-resected and R1 Resected Patients.

[This corrects the article DOI: 10.7759/cureus.2713.].

Pancreatic Cancer: Feasibility and Outcome After Radiochemotherapy with High Dose External Radiotherapy for Non-resected and R1 Resected Patients.

Background Non-resected locally advanced and microscopic positive-margin resected (R1) pancreatic adenocarcinoma are associated with a dismal prognosis. The combination of high dose radiotherapy and concomitant chemotherapy is among the strategies that are used to improve the outcome. The aims of this study were to evaluate the acute and late toxicities and patients' outcome in a retrospective study from a single center. Material and methods From 2009 to 2015, 24 patients, with non-resected locally advanced or R1 resected pancreatic adenocarcinoma, have been treated with concomitant radiochemotherapy, with a median dose of 60 Gy and gemcitabine (50 mg/m2 administered bi-weekly). The acute and late toxicities were evaluated during and after the treatment. Results The actuarial overall survival rates were 39% at 24 months and 8.6% at 36 months. The disease-free survival rates were 32.5% at 24 months and 12.2% at 36 months. Acute toxicities were mainly grade 1 (G1) to grade 2 (G2) except for one patient who presented with severe digestive bleeding potentially linked to the treatment. Late toxicities consisted mainly of G1 digestive toxicities. Conclusion This study confirms the feasibility of high dose radiotherapy combined with gemcitabine-based chemotherapy in patients with locally advanced pancreatic adenocarcinoma. While the outcome remains unsatisfactory, some patients seem to have benefited from this aggressive therapy, which merits to be investigated further.

Unusual Case of Laryngeal Squamous Cell Carcinoma with Cervical Metastasis of a Prostatic Adenocarcinoma: A Case Report.

Brain and Head and neck metastases are rare in prostatic carcinoma patients. In this report we present a very uncommon case of the concomitant occurrence of a prostatic adenocarcinoma with neck metastases and an advanced laryngeal squamous cell carcinoma without neck metastases. The presence of cervical lymph node prostate adenocarcinoma metastasis concomitantly with a laryngeal squamous cell carcinoma is at least intriguing and may remind us of a rare event called "collision tumors". In this case we had the metastatization of 1 carcinoma to the site of the drainage of another carcinoma, but we never found the 2 histological types as close as requested to reach the definition of a collision tumor. This emphasizes the need of histological verification of different sites of recurrence when 2 or more primary cancers are known in a patient, particularly when the treatments of those primary cancers vary widely.

Discovery of Novel Allosteric HCV NS5B Inhibitors. 2. Lactam-Containing Thiophene Carboxylates.

Lomibuvir (1) is a non-nucleoside, allosteric inhibitor of the hepatitis C virus NS5B polymerase with demonstrated clinical efficacy. Further development efforts within this class of inhibitor focused on improving the antiviral activity and physicochemical and pharmacokinetic properties. Recently, we reported the development of this series, leading to compound 2, a molecule with comparable potency and an improved physicochemical profile relative to 1. Further exploration of the amino amide-derived side chain led to a series of lactam derivatives, inspired by the X-ray crystal structure of related thiophene carboxylate inhibitors. This series, exemplified by 12f, provided 3-5-fold improvement in potency against HCV replication, as measured by replicon assays. The synthesis, structure-activity relationships, in vitro ADME characterization, and in vivo evaluation of this novel series are discussed.

Discovery of Novel Thiophene-Based, Thumb Pocket 2 Allosteric Inhibitors of the Hepatitis C NS5B Polymerase with Improved Potency and Physicochemical Profiles.

The hepatitis C viral proteins NS3/4A protease, NS5B polymerase, and NS5A are clinically validated targets for direct-acting antiviral therapies. The NS5B polymerase may be inhibited directly through the action of nucleosides or nucleotide analogues or allosterically at a number of well-defined sites. Herein we describe the further development of a series of thiophene carboxylate allosteric inhibitors of NS5B polymerase that act at the thumb pocket 2 site. Lomibuvir (1) is an allosteric HCV NS5B inhibitor that has demonstrated excellent antiviral activity and potential clinical utility in combination with other direct acting antiviral agents. Efforts to further explore and develop this series led to compound 23, a compound with comparable potency and improved physicochemical properties.

Second-generation antibacterial benzimidazole ureas: discovery of a preclinical candidate with reduced metabolic liability.

Compound 3 is a potent aminobenzimidazole urea with broad-spectrum Gram-positive antibacterial activity resulting from dual inhibition of bacterial gyrase (GyrB) and topoisomerase IV (ParE), and it demonstrates efficacy in rodent models of bacterial infection. Preclinical in vitro and in vivo studies showed that compound 3 covalently labels liver proteins, presumably via formation of a reactive metabolite, and hence presented a potential safety liability. The urea moiety in compound 3 was identified as being potentially responsible for reactive metabolite formation, but its replacement resulted in loss of antibacterial activity and/or oral exposure due to poor physicochemical parameters. To identify second-generation aminobenzimidazole ureas devoid of reactive metabolite formation potential, we implemented a metabolic shift strategy, which focused on shifting metabolism away from the urea moiety by introducing metabolic soft spots elsewhere in the molecule. Aminobenzimidazole urea 34, identified through this strategy, exhibits similar antibacterial activity as that of 3 and did not label liver proteins in vivo, indicating reduced/no potential for reactive metabolite formation.

3-Aryl-4-(arylhydrazono)-1H-pyrazol-5-ones: Highly ligand efficient and potent inhibitors of GSK3beta.

A series of 3-aryl-4-(arylhydrazono)-1H-pyrazol-5-one inhibitors of GSK3beta was developed from a low molecular weight, highly ligand efficient screening hit 1. Hit-to-lead optimization led to a number of highly potent inhibitors, while maintaining the high ligand efficiency of the screening hit.

A practical synthesis of (S) 3-tert-butoxycarbonylamino-2-oxo-2,3,4,5-tetrahydro-1,5-benzodiazepine-1-acetic acid methyl ester as a conformationally restricted dipeptido-mimetic for caspase-1 (ICE) inhibitors.

A simple and versatile method for the synthesis of (S) 3-tert-butoxycarbonylamino-2-oxo-2,3,4,5-tetrahydro-1,5-benzodiazepine-1-acetic acid methyl ester (4), a dipeptide mimetic, has been developed. The regioselective functionalization of the N1 and N5 ring nitrogens and the C3 amino group is demonstrated in the synthesis of an interleukin-1beta converting enzyme inhibitor 13.