Impact of culture dimensionality and matrix composition on morphology, phenotype and drug response in pancreatic cancer models.

Patient-derived in vitro systems are powerful preclinical models that replicate key features of human tumors and enable investigation of cancer biology and drug response. They are particularly promising for pancreatic cancer research. We examined whether culture dimensionality and basement membrane extract (BME) composition affect establishment rates, morphology, proliferation, marker expression, and drug response in patient-derived models of pancreatic ductal adenocarcinoma (PDAC). From 12 PDAC samples, matched two-dimensional primary cell lines (PDCLs) and three-dimensional organoids were established in Cultrex (PDOCs) and Matrigel (PDOMs). PDCLs formed monolayers, while PDOCs and PDOMs developed cystic or dense organoids, independent of BME type. Immunohistochemistry showed no differences in key diagnostic markers between culture systems, and Ki-67 levels were consistently higher in vitro compared to original tumors. Pharmacological testing with five standard chemotherapeutics revealed no significant differences in drug response between dimensionalities or BMEs, although 3D models were detected to be slightly more chemoresistant. In two patients treated with gemcitabine monotherapy, in vitro therapy response correlated with clinical relapse. Our findings indicate that while drug responses are largely patient-specific and independent of dimensionality and matrix composition, 3D models more realistically recapitulate tumor architecture and phenotypes, supporting their value for translational PDAC research.Trial registration: The study was conducted according to the guidelines of the Declaration of Helsinki. Ethical approval was requested and granted by the ethics committee of the Charité Universitätsmedizin Berlin (EA1/157/21) on 26th May 2021.