Chemosensitivity of 3D Pancreatic Cancer Organoids Is Not Affected by Transformation to 2D Culture or Switch to Physiological Culture Medium

SIMPLE SUMMARY: Organoids are increasingly used to investigate patient-specific drug responsiveness since they are thought to be more representative of a patient’s tumor than two-dimensional primary cell cultures. Furthermore, cell culture media that mimic physiological nutrient concentrations have been suggested to improve chemotherapy screens of cultured cells. As both come with increased costs and complexity, we investigated the response of two patient-derived pancreatic cancer organoids (PANCO09b, PANCO11b) growing as 3D organoids versus 2D transformed cell cultures in either conventional or physiological media towards five chemotherapeutics (gemcitabine, paclitaxel, SN-38, 5-fluorouacil, and oxaliplatin). Both patient-derived pancreatic cancer cell cultures showed similar drug-responses when cultured in 3D compared to 2D, as well as upon culture in physiological versus conventional culture media, except for higher sensitivity towards SN-38 when PANCO11b was cultured in 2D or in physiological media. These data show that drug-responsiveness of primary pancreatic cancer cells is not majorly impacted by culture conditions. ABSTRACT: Organoids are increasingly used to investigate patient-specific drug responsiveness, but organoid culture is complex and expensive, and carried out in rich, non-physiological media. We investigated reproducibility of drug-responsiveness of primary cell cultures in 2D versus 3D and in conventional versus physiological cell culture medium. 3D pancreatic ductal adenocarcinoma organoid cultures PANCO09b and PANCO11b were converted to primary cell cultures growing in 2D. Transformed 2D cultures were grown in physiological Plasmax medium or Advanced-DMEM/F12. Sensitivity towards gemcitabine, paclitaxel, SN-38, 5-fluorouacil, and oxaliplatin was investigated by cell viability assays. Growth rates of corresponding 2D and 3D cultures were comparable. PANCO09b had a shorter doubling time in physiological media. Chemosensitivity of PANCO09b and PANCO11b grown in 2D or 3D was similar, except for SN-38, to which PANCO11b cultured in 3D was more sensitive (2D: 8.2 ×10(−3) ± 2.3 ×10(−3) vs. 3D: 1.1 ×10(−3) ± 0.6 ×10(−3), p = 0.027). PANCO09b and PANCO11b showed no major differences in chemosensitivity when cultured in physiological compared to conventional media, although PANCO11b was more sensitive to SN-38 in physiological media (9.8 × 10(−3) ± 0.7 × 10(−3) vs. 5.2 × 10(−3) ± 1.8 × 10(−3), p = 0.015). Collectively, these data indicate that the chemosensitivity of organoids is not affected by culture medium composition or culture dimensions. This implies that organoid-based drug screens can be simplified to become more cost-effective.