Growth and study of three dimensional pancreatic cancer spheroids
Pancreatic cancer is the third leading cause of cancer-related deaths in the U.S., and pancreatic ductal adenocarcinoma (PDAC) makes up around ninety percent of these cases. Due to its late diagnosis and extreme chemoresistance, PDAC is highly lethal with a poor prognosis. The tumor microenvironment (TME) is a main reason for this drug resistance; cancer cells are surrounded by a dense stroma otherwise known as the desmoplastic reaction, consisting of fibroblasts, pancreatic stellate cells, and extracellular matrix (ECM) components. Therefore, the TME is an important factor to reproduce when conducting experiments in vitro. Three dimensional spheroids are a more physiologically representative model of in vivo tumors because they mimic the TME more accurately by allowing cancer cells to communicate and interact with stromal cells and the ECM. In this study, we co-cultured PS1 stellate cells (one of the main stromal cell types in PDAC tumors) with different pancreatic cancer cell lines (PATU-8902, PANC-1, MiaPaCa-2, and SU86) in various ratios to observe growth patterns for each combination. After establishing the optimal ratios of PS1 cells and the cancer cells, the spheroids were harvested and underwent H&E staining to more closely examine their anatomical structure. We also treated spheroids overnight with a combination of gemcitabine, nan-paclitaxel, and cisplatin as well as Vitamin C and measured their response to metabolic modulators through a seahorse assay. We found that the combination of PS1-PATU8902 and PS1-PANC1 produced the most compact spheres in ratios of 10,000 cells/100 microliters to 5,000 cells/100 microliters and 5,000 cells/100 microliters to 10,000 cells/100 microliters respectively, and these two types of spheres will be used in the future for further research on the role of TME in pancreatic cancer cells chemoresistance and development of new therapies for patients with PDAC.