FGFR1 clustering with engineered tetravalent antibody improves the efficiency and modifies the mechanism of receptor
Marta Pozniak1, Aleksandra Sokolowska-Wedzina1, Kamil Jastrzebski2
1Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Poland.
Abstract:
Fibroblast growth factor receptor 1 (FGFR1) transmits signals through the plasma membrane regulating essential cellular processes like division, motility, metabolism, and death. Overexpression of FGFR1 is observed in numerous tumors and thus constitutes an attractive molecular target for selective cancer treatment. Targeted anti-cancer therapies aim for the precise delivery of drugs into cancer cells, sparing the healthy ones and thus limiting unwanted side effects. One of the key steps in targeted drug delivery is receptor-mediated endocytosis. Here, we show that the efficiency and the mechanism of FGFR1 internalization are governed by the spatial distribution of the receptor in the plasma membrane. Using engineered antibodies of different valency, we demonstrate that dimerization of FGFR1 with bivalent antibody triggers clathrin-mediated endocytosis (CME) of the receptor. Clustering of FGFR1 into larger oligomers with tetravalent antibody stimulates fast and highly efficient uptake of the receptor that occurs via two distinct mechanisms: CME and dynamin-dependent clathrin-independent endocytic routes. Furthermore, we show that all endocytic pathways engaged in FGFR1 internalization do not require receptor activation. Our data provide novel insights into the mechanisms of intracellular trafficking of FGFR1 and constitute guidelines for development of highly internalizing antibody-based drug carriers for targeted therapy of FGFR1-overproducing cancers.
Insights
Antibody valency controls Fibroblast growth factor receptor 1 (FGFR1) internalization. Dimerization triggers clathrin-mediated endocytosis, while larger clusters enhance uptake via multiple pathways for targeted cancer therapy.
Area of Science:
- Cell Biology
- Molecular Oncology
- Immunology
Background:
- Fibroblast growth factor receptor 1 (FGFR1) is crucial for cellular functions and its overexpression is linked to various cancers.
- Targeted cancer therapies rely on efficient drug delivery into cancer cells, often via receptor-mediated endocytosis.
- Understanding FGFR1 internalization mechanisms is key for developing effective antibody-based cancer treatments.
Purpose of the Study:
- To investigate how the spatial distribution of FGFR1 on the plasma membrane influences its internalization.
- To determine the role of antibody valency in mediating FGFR1 endocytosis.
- To provide insights for designing improved antibody-based drug delivery systems for FGFR1-overexpressing cancers.
Main Methods:
- Utilized engineered antibodies with varying valencies (bivalent and tetravalent) to interact with FGFR1.
- Employed advanced microscopy and biochemical assays to track FGFR1 internalization and identify endocytic pathways.
- Investigated the necessity of FGFR1 activation for receptor uptake.
Main Results:
- FGFR1 dimerization induced by bivalent antibodies triggers clathrin-mediated endocytosis (CME).
- Tetravalent antibodies, forming larger FGFR1 clusters, promote rapid and efficient uptake via both CME and clathrin-independent pathways.
- FGFR1 internalization occurs independently of receptor activation, regardless of the endocytic route.
Conclusions:
- The spatial arrangement of FGFR1 dictates its endocytic mechanism and efficiency.
- Antibody valency is a critical factor in modulating FGFR1 internalization for targeted drug delivery.
- These findings offer a rational basis for developing potent antibody-based therapeutics against FGFR1-driven cancers.
