Targeting EGFR/IGF-IR Functional Crosstalk in 2D and 3D Triple-Negative Breast Cancer Models to Evaluate Tumor Progression.

Breast cancer is the most prevalent solid tumor diagnosed in women worldwide, remaining a leading cause of cancer-related mortality. Among its subtypes, triple-negative breast cancer (TNBC) is characterized by high aggressiveness and heterogeneity, accounting for approximately 90% of breast cancer-related deaths. Receptor tyrosine kinases (RTKs), such as epidermal growth factor receptor (EGFR) and the insulin-like growth factor I receptor (IGF-IR), are critical cell growth and survival regulators, with their dysregulation closely related to therapy resistance in breast cancer. Studies on RTK targeting have shown promise, and recently attention has shifted toward developing more physiologically relevant preclinical models. Unlike traditional two-dimensional (2D) cell cultures, 3D models such as spheroids better mimic the complex nature of the tumor microenvironment (TME), offering a more accurate representation of tumor behavior and progression. This study utilized both 2D and 3D culture models to assess the effects of EGFR and IGF-IR inhibition, individually and in combination, in two TNBC cell lines with distinct metastatic potential. The results demonstrate that both receptors play critical roles in regulating key cellular functions, including migration, expression of epithelial-to-mesenchymal transition (EMT) markers and matrix metalloproteinases (MMPs). The use of 3D spheroid models enabled the evaluation of additional functional properties, such as spheroid growth and dissemination, revealing treatment-dependent responses to combined receptor inhibition. Overall, this dual-model approach underscores the importance of incorporating 3D culture systems in preclinical cancer research and provides new insights into the regulatory roles of EGFR and IGF-IR in TNBC progression.