Characterization of a dengue NS4B inhibitor originating from an HCV small molecule library.

Dengue is the most important mosquito-transmitted viral disease and a major global health concern. Over the last decade, dengue virus (DENV) drug discovery and development has intensified, however, this has not resulted in approved DENV-specific antiviral treatments yet. DENV and hepatitis C virus (HCV) belong to the same Flaviviridae family and, in contrast to DENV, antiviral treatments for HCV have been licensed. Therefore, applying the knowledge gained on anti-HCV drugs may foster the discovery and development of dengue antiviral drugs. Here, we screened a library of compounds with established anti-HCV activity in a DENV-2 sub-genomic replicon inhibition assay and selected compounds with single-digit micromolar activity. These compounds were advanced into a hit-to-lead medicinal chemistry program resulting in lead compound JNJ-1A, which inhibited the DENV-2 sub-genomic replicon at 0.7 µM, in the absence of cytotoxicity. In addition, JNJ-1A showed equipotent antiviral activity against DENV serotypes 1, 2, and 4. In vitro resistance selection experiments with JNJ-1A induced mutation T108I in non-structural protein 4B (NS4B), pointing towards a mechanism of action linked to this protein. Collectively, we described the discovery and characterization of a novel DENV inhibitor potentially targeting NS4B.

Chemical genetic screening of KRAS-based synthetic lethal inhibitors for pancreatic cancer.

Pancreatic cancer is one of the deadliest diseases largely due to difficulty in early diagnosis and the lack of effective treatments. KRAS is mutated in more than 90% of pancreatic cancer patients, and oncogenic KRAS contributes to pancreatic cancer tumorigenesis and progression. In this report, using an oncogenic KRASV12-based pancreatic cancer cell model, we developed a chemical genetic screen to identify small chemical inhibitors that selectively target pancreatic cancer cells with gain-of-function KRAS mutation. After screening ~3,200 compounds, we identified one compound that showed selective synthetic lethality against the KRASV12 transformed human pancreatic ductal epithelial cell over its isogenic parental cell line. These selective KRASV12-synthetic lethal compounds may serve as leads for subsequent development of clinically-effective treatments for pancreatic cancer.

Substrate specificity and screening of the integral membrane protease Pla.

This paper reports a study to find small peptide substrates for the important virulence factor of Yersinia pestis, plasminogen activator, Pla. The method used to find small substrates for this protease is reported along with studies examining the ability of these peptides to inhibit activity of the enzyme. Through the use of parallel synthesis and positional scanning, small tripeptides were identified that are viable substrates for the protease.

Synthesis and screening of 3-substituted thioxanthen-9-one-10,10-dioxides.

This manuscript describes methods appropriate for the parallel synthesis of libraries based on the tricyclic thioxanthen-9-one-10,10-dioxide scaffold. The novel compounds were synthesized from previously reported 3-chlorothioxanthen-9-one-10,10-dioxide and commercially available 3-carboxylic acid thioxanthen-9-one-10,10-dioxide. The library members were screened for activity in a fluorescence polarization assay for inhibitors of BRCT domains of breast cancer gene 1 and in cell-based secreted alkaline phosphatase reported replicon system for activity against hepatitis C virus.

Intramolecular vinylsilane-oxocarbenium condensations: concise assembly of cis-bicyclic ether arrays.

Lewis acid-mediated intramolecular attack of vinylsilanes at tethered oxonium precursors 1 results in a rapid assembly of the cis-fused bicyclic ether species 3, with complete regio- and stereospecific control, and in some cases near-quantitative yield. Continued investigation suggests a general approach to a variety of such ether frameworks.