Exploring the Efficacy of 2D and 3D Cell Culture Models to Unravel Chemoresistance Mechanisms in Pleural Mesothelioma: An In-Depth In Vitro and In Vivo Comparative Study

Pleural mesothelioma (PM) is a highly aggressive cancer with limited treatment efficacy and poor prognosis. Conventional two-dimensional (2D) culture models fail to replicate the tumour microenvironment (TME), limiting their translational relevance. Here, we establish a three-dimensional (3D) spheroid model to investigate chemotherapy resistance across different PM subtypes. Compared to 2D cultures, 3D spheroids display enhanced resistance to cisplatin-pemetrexed, with elevated IC₅₀ values, reduced apoptosis, and altered cell cycle profiles. Seahorse metabolic analysis reveals preserved oxidative metabolism, while molecular profiling highlights subtype-specific miRNA signatures aligned with patient data. Proteomic analysis of 3D cultures identifies upregulation of PI3K/AKT and Notch/VEGF signalling, implicating these pathways in treatment resistance. Histological assessment of xenografts further confirms 3D model fidelity in capturing tumour fibrosis, necrosis, and response to therapy. These findings position the 3D spheroid system as a robust and physiologically relevant platform for modelling drug resistance and guiding therapeutic development in PM.