From Structure to Function: The Impact of EGFR and IGF-IR in 3D Breast Cancer Spheroids.

Background: Breast cancer, one of the most researched cancers in oncology, remains the primary cause of cancer-related mortality in women. Its biological complexity, which includes phenotypic, genetic, and microenvironmental aspects, makes modeling and treatment quite difficult. The need for more physiologically realistic models is highlighted by the comparison of two-dimensional (2D) cell cultures with 3D breast-cancer-derived spheroids, which discloses how important pathways such as epidermal growth factor receptor (EGFR) and insulin-like growth factor I receptor (IGF-IR) influence cell behavior and extracellular matrix (ECM) macromolecular expression. Methods: The purpose of this study was to utilize novel 3D cell platforms to assess the effect of inhibiting the EGFR and IGF-IR pathways, alone or in combination, on the functional properties and the expression levels of certain matrix metalloproteinases (MMPs) which are implicated in breast cancer progression (i.e., triple-negative and luminal A breast cancer subtypes) and related with the EGFR and IGF-ΙR molecular network, as also demonstrated through STRING analysis. Results: Our results demonstrated potential crosstalk between EGFR and IGF-IR signaling, which influences cell proliferation and spheroid growth, dissemination, and migration. Significant phenotypic changes proposed between 2D and 3D cell cultures, and alterations in the expression of MMPs, were also recorded. Conclusions: Both breast cancer cell lines retained acknowledged characteristics across the tested models while also exhibiting new, condition-dependent properties. Overall, our findings enhance our understanding on the interplay between the EGFR and IGF-IR pathways and underscore the value of 3D models in revealing key biological processes underlying distinct breast cancer phenotypes.