Cancer-associated VEGFR2R1032Q sustains receptor activation also by promoting ligand-independent hetero-dimerization with co-expressed wild-type VEGFR2 and translocation into lipid rafts

Cosetta Ravelli; Michela Corsini; Roberto Bresciani; Angela M Rizzo; Luca Zammataro; Paola A Corsetto; Elisabetta Grillo; Stefania Mitola

doi:10.1016/j.neo.2025.101195

Cancer-associated VEGFR2^R1032Q sustains receptor activation also by promoting ligand-independent hetero-dimerization with co-expressed wild-type VEGFR2 and translocation into lipid rafts

Neoplasia. 2025 Jun 14:67:101195. doi: 10.1016/j.neo.2025.101195. Online ahead of print.

Authors

Cosetta Ravelli¹, Michela Corsini¹, Roberto Bresciani², Angela M Rizzo³, Luca Zammataro⁴, Paola A Corsetto³, Elisabetta Grillo¹, Stefania Mitola⁵

Affiliations

¹ Department of Molecular and Translational Medicine, University of Brescia, Brescia, 25123, Italy; The Mechanobiology Research Center, University of Brescia, Brescia, Italy.
² Department of Molecular and Translational Medicine, University of Brescia, Brescia, 25123, Italy; The Mechanobiology Research Center, University of Brescia, Brescia, Italy; Highly Specialized Laboratory, ASST Spedali Civili of Brescia, Brescia, 25123, Italy.
³ Department of Pharmacological and Biomolecular Sciences, University of Milan, Milano, 20133, Italy.
⁴ Lunan Foldomics LLC, Houston, TX, 77057, USA.
⁵ Department of Molecular and Translational Medicine, University of Brescia, Brescia, 25123, Italy; The Mechanobiology Research Center, University of Brescia, Brescia, Italy. Electronic address: stefania.mitola@unibs.it.

Abstract

The substitution R1032Q is the most frequent non-synonymous mutation of the vascular endothelial growth factor receptor 2 (VEGFR2) in cancer patients, classified as a loss-of-function variant. Here we characterize the molecular bases of its role in cancer, demonstrating that it lacks significant activity and pro-oncogenic effects in VEGFR2-negative tumor cells, while being able to sustain the tumorigenic potential of VEGFR2-positive cancer cells. By implementing a cell model that allows expression of either VEGFR2^R1032Q alone or in combination with VEGFR2^WT, we showed that the effects of mutated VEGFR2 are at least in part due to the ability of VEGFR2^R1032Q to form functional heterodimers with co-expressed VEGFR2^WT that result in increased kinase activity and receptor phosphorylation. This was associated with reduced mobility of the receptor on the membrane, linked to its translocation into detergent-resistant membrane (DRM) domains (e.g. lipid rafts), which showed alterations in lipid compositions and structure. These data shed light on a novel oncogenic mechanism of activation of VEGFR2, clarifying the paradoxical loss-of-function nature of the substitution R1032Q of VEGFR2.

Keywords: Dimerization; Ligand-independent receptor hyperactivation; Membrane microdomains; R1032Q mutant; VEGFR2.