Discovery of indoline-based, natural-product-like compounds as probes of focal adhesion kinase signaling pathways.

With the goal of identifying small molecule modulators of protein−protein interactions, we developed a solid-phase synthesis method, which was then successfully utilized in a library generation of 164 aminoindoline-derived, natural-product-like compounds. This library and several other related intermediates synthesized during this project were then subjected to different biological assays in search of small molecule modulators of focal adhesion kinase (FAK)-mediated signaling pathways. This study included (i) an in vitro, full length FAK inhibition assay, (ii) a cell proliferation assay, and (iii) a wound healing assay. In FAK inhibition assay, eight library members (5−12) and three aminoindoline derivatives (13, 14, and 2) were identified as promising candidates. Compounds 13 and 2 inhibited the FAK activity by 25−45% at 10 μM. These two lead compounds also showed activity in a wound healing assay. To our knowledge, these aminoindoline-derived small molecules belong to a new family of FAK inhibitors.