Abstract
Targeted delivery of anticancer drugs using antibodies specific for tumor-associated antigens represents one of the most important approaches in current immuno-oncology research. Fibroblast growth factor receptor 1 (FGFR1) has been demonstrated to be a high-frequency targetable oncogene specific for smoking-associated lung cancers, present in over 20% of lung squamous cell carcinoma cases. This report describes the generation of a potent, fully human antibody fragment in scFv-Fc format efficiently targeting FGFR1. Antibody phage display was used to select high-affinity scFv antibody fragments against the extracellular domain of FGFR1(IIIc). Enzyme immunoassay (ELISA) and surface plasmon resonance (SPR) analysis were used for antibody screening and characterization. The best binder (named D2) was cloned to diabody and Fc fusion formats. All D2 antibodies demonstrated high affinity for FGFR1 with dissociation constants of 18 nmol/L (scFvD2), 0.82 nmol/L (scFvD2 diabody), and 0.59 nmol/L (scFvD2-Fc). scFvD2 was found to be exquisitely selective for FGFR1 versus other FGFR family members and bound FGFR1 even in the presence of its natural ligand FGF2, as shown by competitive analysis. Confocal microscopy revealed that scFvD2-Fc was specifically and rapidly internalized by a panel of cell lines overexpressing FGFR1. Finally, it was demonstrated that scFvD2-Fc mediated specific delivery of a cytotoxic payload into lung cancer cells harboring oncogenic FGFR1 gene amplifications.Implications: This study reports a highly specific internalizing antibody fragment that can serve as a therapeutic targeting agent for efficient delivery of cytotoxic drugs into FGFR1-positive lung cancer cells. Mol Cancer Res; 15(8); 1040-50. ©2017 AACR.
Highlights
Lung cancer is a leading cause of cancer-related mortality worldwide, accounting for more than 1.6 million deaths in 2015 [1] and remains one of the most challenging diseases to treat
Antibody fragments in scFv format were isolated from recombinant Tomlinson I and J human scFv libraries by phage display using ECD_FGFR1-Fc as an antigen
368 randomly picked colonies from the third round of selection were tested for binding to ECD_FGFR1-Fc and Fc by ELISA, what resulted in yielding 48 Fibroblast growth factor receptor 1 (FGFR1)-specific scFv clones (Fig. 1A; Supplementary Fig. S1) which were subsequently screened by surface plasmon resonance (SPR) using a high-density chip coated with FGFR1 (Fig. 1B)
Summary
Lung cancer is a leading cause of cancer-related mortality worldwide, accounting for more than 1.6 million deaths in 2015 [1] and remains one of the most challenging diseases to treat. Lung cancer is traditionally classified into non–small cell lung cancer (NSCLC) and small cell lung cancer The most common NSCLC subtypes are adenocarcinoma and squamous cell carcinoma A major advance in lung cancer diagnosis and treatment in the past decade is the concept of personalized medicine, where therapeutic decisions are based on histologic, and specific molecular characteristics of a patient's tumor [3, 4]. A number of somatic genetic alterations have been identified across lung cancer subtypes [4,5,6,7]. Significant progress has been made in the development of targeted drugs for patients whose tumors harbor anaplastic lymphoma kinase (ALK) gene fusions
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