A novel non-phosphorylated potential antitumoral peptide inhibits STAT3 biological activity.

STAT3 (Signal Transducer and Activator of Transcription 3) is an SH2 (Src Homology 2)-domain containing transcription factor that plays a key role in cancer, by regulating as a dimer the expression of genes implicated in the main processes of the tumorigenesis. Therefore, STAT3 and more particularly its dimeric form has emerged as promising targets for cancer therapy. STAT3 dimerization occurs through reciprocal interaction between the SH2 domain of one monomer and the phosphorylated tyrosine residue of a second one.

STAT3-stathmin interactions control microtubule dynamics in migrating T-cells.

T-cell migration is a complex highly coordinated process that involves cell adhesion to the high endothelial venules or to the extracellular matrix by surface receptor/ligand interactions, cytoskeletal rearrangements, and phosphorylation-dependent signaling cascades. The mechanism(s) that regulates T-cell migration is of considerable relevance for understanding the pathogenesis of various diseases, such as chronic inflammatory diseases and cancer metastasis. This study was designed to identify potential involvement of STAT3, a latent transcription factor, in mediating integrin-induced T-cell migration.

New syntheses of tetrazolylmethylphenylalanine and O-malonyltyrosine as pTyr mimetics for the design of STAT3 dimerization inhibitors.

Investigation within the pTyr-binding pocket of the STAT3 SH2 domain led us to develop a novel synthesis of two pTyr mimetics, l-tetrazolylmethylphenylalanine (l-Tmp) and l-O-malonyltyrosine (l-OMT), that were next incorporated in a high affinity ligand of STAT3 SH2 domain. Biological evaluation of peptidomimetics on STAT3 dimerization identified l-OMT as the first non-phosphorus pTyr mimetic so far reported against STAT3 SH2 domain, harboring an activity similar to that of the Pmp-containing reference peptidomimetic.

Novel 1,4-benzodiazepine derivatives with antiproliferative properties on tumor cell lines.

Novel 1,4-benzodiazepine compounds were synthesized and evaluated for their ability to inhibit the proliferation of tumor cells. Some compounds revealed activities in the micromolar range and were more efficient than reference compound Ro 5-4864. Preliminary SAR helped to identify critical motifs for antiproliferative activity and led to the discovery of a compound selective for a melanoma cell line, known for its resistance to chemotherapy.

Sialyl Lewis(x) analogs based on a quinic acid scaffold as the fucose mimic.

(-)-Quinic acid was used as a starting material for the preparation of sialyl Lewis(x) mimetics in order to target E-selectin. Spatial orientation of the hydroxyl groups of quinic acid could mimic the l-fucose ones. Introduction of a side chain ending with a carboxylic acid was effected to replace the sialic acid interaction at the carbohydrate recognition domain.