Anti-Cancer Activity Profiling of Chemotherapeutic Agents in 3D Co-Cultures of Pancreatic Tumor Spheroids with Cancer-Associated Fibroblasts and Macrophages

SIMPLE SUMMARY: Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive cancers, with a five-year survival rate of less than 8%. There is a need to develop drugs with anti-invasive activity and in vitro tumor models for effective drug screening to improve patient outcomes. Since PDAC invasiveness is mainly induced by tumor-associated stromal cells, we aimed to develop a three-dimensional (3D) PDAC tumor model that mimics in vivo conditions. Additionally, we examined the usefulness of this model for evaluating chemotherapeutic drugs. We succeeded in establishing a 3D co-culture model of multicellular PDAC tumor spheroids, cancer-associated fibroblasts, and tumor-associated macrophages using a microfluidic channel chip platform. We also demonstrated the suitability of this model for evaluating cell-type dependent cytotoxicity, anti-invasive activity, and the association between the two. These results may help develop a novel system for screening the efficacy of chemotherapeutic drugs against PDAC and other solid tumors in the future. ABSTRACT: Activated pancreatic stellate cells (aPSCs) and M2 macrophages modulate tumor progression and therapeutic efficacy in pancreatic ductal adenocarcinoma (PDAC) via epithelial-mesenchymal transition (EMT). Here, our aim was to analyze the anti-invasion effects of anti-cancer agents where EMT-inducing cancer-stroma interaction occurs under three-dimensional (3D) culture conditions. We used microfluidic channel chips to co-culture pancreatic tumor spheroids (TSs) with aPSCs and THP-1-derived M2 macrophages (M2 THP-1 cells) embedded in type I collagen. Under stromal cell co-culture conditions, PANC-1 TSs displayed elevated expression of EMT-related proteins and increased invasion and migration. When PANC-1 TSs were exposed to gemcitabine, 5-fluorouracil, oxaliplatin, or paclitaxel, 30–50% cells were found unaffected, with no significant changes in the dose-response profiles under stromal cell co-culture conditions. This indicated intrinsic resistance to these drugs and no further induction of drug resistance by stromal cells. Paclitaxel had a significant anti-invasion effect; in contrast, oxaliplatin did not show such effect despite its specific cytotoxicity in M2 THP-1 cells. Overall, our findings demonstrate that the TS-stroma co-culture model of PDAC is useful for activity profiling of anti-cancer agents against cancer and stromal cells, and analyzing the relationship between anti-stromal activity and anti-invasion effects.