Synthesis of beta-(1-->4)-oligo-D-mannuronic acid neoglycolipids.

Mammalian Toll-like receptors (TLRs) play important roles in host immune defense. The activation of TLR and down-stream signaling pathways have great impact on human physiology. Chemically diverse microbial products as well as synthetic ligands serve as agonists for these receptors. Recently, synthetic TLR ligands are being exploited as useful therapeutic agents for a variety of diseases including infections, inflammatory diseases, and cancers. Alginate polymers and oligosaccharides are strong immune stimulants mediated by TLR2/4, but synthesis of alginate oligomers is rarely studied. Reported here are the design and chemical synthesis of two beta-(1-->4)-di- and beta-(1-->4)-tri-d-mannuronic acid neoglycolipids 1 and 2 as potential TLR ligands. By using 4,6-di-O-benzylidene-protected 1-thio mannoside 7 as a glycosyl donor, the diastereoselective beta-d-mannosylation protocol provides the beta-(1-->4)-d-mannobiose and beta-(1-->4)-d-mannotriose derivatives, which upon regioselective oxidation with TEMPO/BAIB oxidation system yield the corresponding beta-(1-->4)-d-mannuronic acid containing neoglycolipids 1 and 2.

Free paclitaxel-loaded E-selectin binding peptide modified micelle self-assembled from hyaluronic acid-paclitaxel conjugate inhibit breast cancer metastasis in a murine model.

The present work seeks to construct a nanovehicle for the efficient suppression of breast cancer metastasis through targeting E-selectin on tumor vascular endothelial cells and hyaluronic acid-receptor on tumor cells. Herein, a new ligand-PEG-lipid conjugate, E-selectin binding peptide-polyethene glycol-1-octadecylamine (Esbp-PEG-OA), was used as the targeting molecule of micelle self-assembled form hyaluronic acid-paclitaxel (HA-PTX) conjugate. When loaded with free PTX, the micelles (Esbp-HA-PTX/PTX) exhibited nanoscale particle size with high drug-loading capacity (up to 31.5%). In vitro release study showed that the conjugated and entrapped PTX released simultaneously. Cellular uptake of micelles confirmed that Esbp-HA-PTX micelles could be specifically and efficiently internalized into E-selectin expressing human umbilical vein endothelial cells (HUVEC) and 4T1 breast cancer cells via receptor-meditated endocytosis. In vitro cytotoxicity assay further revealed that Esbp-HA-PTX/PTX micelles significantly improved the selectivity of PTX for killing the two cell types compared with PTX solution formulation. More importantly, Esbp-HA-PTX micelles raised the accumulation of payload in tumor through targeting two cell types in the tumor microenvironment simultaneously, resulting in marked in vivo inhibition of tumor growth, intratumoral microvessel density and metastasis, and decreased systemic toxicity over solution formulation. Overall, Esbp-HA-PTX/PTX micelle is promising in therapy of breast cancer metastasis.

Discovery of Brigatinib (AP26113), a Phosphine Oxide-Containing, Potent, Orally Active Inhibitor of Anaplastic Lymphoma Kinase.

In the treatment of echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase positive (ALK+) non-small-cell lung cancer (NSCLC), secondary mutations within the ALK kinase domain have emerged as a major resistance mechanism to both first- and second-generation ALK inhibitors. This report describes the design and synthesis of a series of 2,4-diarylaminopyrimidine-based potent and selective ALK inhibitors culminating in identification of the investigational clinical candidate brigatinib. A unique structural feature of brigatinib is a phosphine oxide, an overlooked but novel hydrogen-bond acceptor that drives potency and selectivity in addition to favorable ADME properties. Brigatinib displayed low nanomolar IC50s against native ALK and all tested clinically relevant ALK mutants in both enzyme-based biochemical and cell-based viability assays and demonstrated efficacy in multiple ALK+ xenografts in mice, including Karpas-299 (anaplastic large-cell lymphomas [ALCL]) and H3122 (NSCLC). Brigatinib represents the most clinically advanced phosphine oxide-containing drug candidate to date and is currently being evaluated in a global phase 2 registration trial.

Fragment growing and linking lead to novel nanomolar lactate dehydrogenase inhibitors.

Lactate dehydrogenase A (LDH-A) catalyzes the interconversion of lactate and pyruvate in the glycolysis pathway. Cancer cells rely heavily on glycolysis instead of oxidative phosphorylation to generate ATP, a phenomenon known as the Warburg effect. The inhibition of LDH-A by small molecules is therefore of interest for potential cancer treatments. We describe the identification and optimization of LDH-A inhibitors by fragment-based drug discovery. We applied ligand based NMR screening to identify low affinity fragments binding to LDH-A. The dissociation constants (K(d)) and enzyme inhibition (IC(50)) of fragment hits were measured by surface plasmon resonance (SPR) and enzyme assays, respectively. The binding modes of selected fragments were investigated by X-ray crystallography. Fragment growing and linking, followed by chemical optimization, resulted in nanomolar LDH-A inhibitors that demonstrated stoichiometric binding to LDH-A. Selected molecules inhibited lactate production in cells, suggesting target-specific inhibition in cancer cell lines.