Therapeutic Discovery A Novel Monoclonal Antibody to Fibroblast Growth Factor 2 Effectively Inhibits Growth of Hepatocellular Carcinoma Xenografts

Expression of fibroblast growth factor 2 (FGF2) is believed to be a contributing factor to the growth of a number of tumor types, including hepatocellular carcinoma (HCC). However, the potential of monoclonal antibodies that neutralize FGF2 for treatment of patientswith cancer has not yet been explored in clinical trials. We therefore generated a novel monoclonal antibody (mAb), GAL-F2, specific for FGF2 and characterized its properties in vitro and in vivo. GAL-F2binds to adifferent epitope than several previous anti-FGF2mAbs tested. This novel epitope was defined using chimeric FGF1/FGF2 proteins and alanine scanning mutagenesis and was shown to comprise amino acids in both the amino andcarboxy regions of FGF2.GAL-F2blockedbinding of FGF2 to each of its four cellular receptors, strongly inhibited FGF2-induced proliferation and downstream signaling in human umbilical vein endothelial cells, and inhibited proliferation and downstream signaling in two HCC cell lines. Moreover, GAL-F2, administered at 5 mg/kg i.p. twice weekly, potently inhibited growth of xenografts of the SMMC-7721, HEP-G2, and SK-HEP-1 human HCC cell lines in nude mice, and in some models, had a strong additive effectwith an anti-VEGFmAbor sorafenib. TreatmentwithGAL-F2 also blocked angiogenesis and inhibiteddownstreamcellular signaling in xenografts, indicating its antitumormechanismof action. Our report supports clinical testing of a humanized form of the GAL-F2mAb for treatment of HCC and potentially other cancers. Mol Cancer Ther; 11(4); 864–72. 2012 AACR.