Discovery and optimization of a guanylhydrazone-based small molecule to replace bFGF for cell culture applications

SUMMARY Replacing growth factors with a synthetic alternative molecule is an attractive opportunity to increase consistency, scalability and cost-effectiveness of cell-based products. Herein, we describe the discovery of a chemical class of FGFR1 agonists mimicking the action of basic fibroblast growth factor (bFGF), an essential component of cell-culture media. The guanylhydrazone-based molecule, TCB-32, was identified via structure-based virtual screening on the orthosteric binding site of FGFR1. It was shown to significantly increase cell proliferation by activating the FGFR1 signalling pathway like bFGF and exhibited enhanced thermostability over bFGF by containing activity over the course of several days. After extensive structure-activity relationship studies it was possible to increase potency and efficacy leading to three highly potent agonists. This finding has the potential to remove current bottlenecks in large-scale cell production as required for applications like cultivated meat or cell therapy. GRAPHICAL ABSTRACT HIGHLIGHTS Discovery of a highly potent small molecule to replace bFGF in serum-free medium Activation of proliferation through the FGFR1-signalling pathway Enhanced thermal stability over bFGF SAR led to three small molecules with decreased EC50, named TCB-494, TCB-541 and TCB-621