Development of novel in vitro 3D cell models of ovarian cancer for drug screeningKokondoska Grgič, Vesna (Avtor) Sinreih, Maša (Mentor) Jovchevska, Ivana (Komentor) ovarian cancer3D modelsEMT3D bioprintingchemoresistanceHigh grade serous ovarian cancer (HGSOC) is the most aggressive and lethal subtype of ovarian cancers (OC). Although patients initially respond to platinum-based chemotherapy, most eventually relapse due to the development of chemoresistance. One of the major limitations lies in the use of two-dimensional (2D) cultures, which do not accurately reflect the complex architecture and microenvironment of solid tumours. The aim of this doctoral research was to develop and characterise advanced three-dimensional (3D) in vitro models of HGSOC that more closely resemble ovarian tumour biology and improve the predictive value of preclinical drug testing. Four representative HGSOC cell lines (OVCAR-4, OVSAHO, COV362, and Kuramochi) were used to establish 3D spheroid models via ultra-low attachment culture and 3D bioprinting. These models were compared with 2D cultures through detailed morphological assessment, proliferation analysis, invasion assays, viability testing, gene expression profiling, immunocytochemistry, flow cytometry, and RNA sequencing. The findings demonstrate clear biological differences between 2D and 3D models. The 3D models developed compact spheroid structures with rim–core organization, reduced proliferation rates compared with 2D, and distinct epithelial–mesenchymal transition (EMT) and extracellular matrix (ECM) gene expression patterns. Importantly, carboplatin sensitivity was significantly lower in 3D models, reflected by higher IC₅₀ values, indicating increased resistance that more closely mirrors clinical observations. Integration with TCGA HGSOC transcriptomic data further supported the clinical relevance of the identified resistance-associated pathways. In addition, 3D bioprinting enabled the production of reproducible and scalable tumour models suitable for parallel drug testing. Overall, this work provides robust and biologically relevant 3D models for OC that bridge the gap between simplified cell culture systems and patient tumours.20262026-07-03 12:46:28Doktorsko delo/naloga184312sl