Aptamer-mediated impairment of EGFR-integrin αvβ3 complex inhibits vasculogenic mimicry and growth of triple-negative breast cancers

Current treatment options for triple-negative breast cancers (TNBCs) is limited by the absence of well-defined biomarkers, excluding a targeted therapy. Notably, epidermal growth factor receptor (EGFR) is overexpressed in a great proportion of TNBCs and is a negative prognostic factor. In clinical trials, however, existing EGFR inhibitors showed disappointing outcome. Oligonucleotide aptamers are a valid alternative to antibodies for diagnostic and therapeutic uses. Here, we prove that, when applied to aggressive TNBC cell lines with unique stem-like plasticity, the anti-EGFR CL4 aptamer, but not erlotinib or cetuximab, prevents the vasculogenic mimicry (VM) capability of the cells and destroys previously formed channels in three-dimensional culture. Notably, we found that CL4 impairs the matrix-induced integrin αvβ3 interaction with EGFR and integrin αvβ3-dependent cell adhesion. Consistently, the aptamer strongly inhibits VM and tumor growth in a xenograft TNBC model. These data suggest that in TNBC cells, EGFR may cooperate with integrin αvβ3 to regulate integrin binding to extracellular ligands required for VM, and EGFR-targeting by CL4 aptamer may counteract this event. Overall, we demonstrate a novel mechanism of action for CL4 related with integrin αvβ3-EGFR interaction, that may help to develop new oligonucleotide-based strategy addressing unmet need for TNBCs therapy.