Combined PET Radiotracer Approach Reveals Insights into Stromal Cell-Induced Metabolic Changes in Pancreatic Cancer In Vitro and In Vivo.

Autor: Doctor, Alina, Laube, Markus, Meister, Sebastian, Kiss, Oliver C., Kopka, Klaus, Hauser, Sandra, Pietzsch, Jens
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Zdroj: Cancers; Oct2024, Vol. 16 Issue 19, p3393, 20p
Abstrakt: Simple Summary: Pancreatic cancer is surrounded by a dense fibrotic environment due to the activity of pancreatic stellate cells (PSCs). This hinders the effectiveness of treatment by limiting drug penetration and oxygen delivery. To better understand this, PSCs and cancer cells were studied in laboratory models using radiotracer imaging techniques. The results indicated that while glucose uptake and hypoxia were similar between cancer cells alone and in combination with PSCs, a specific marker of fibrosis (FAPα) was significantly higher in PSC-rich environments. In mice, the marker in question decreased in tumors with only PSCs, indicating that the cells had died. Conversely, the biomarker increased over time in tumors containing both cancer cells and PSCs, suggesting that mouse cells had invaded. This study sheds light on how the tumor environment influences metabolism and thus provides insights for more targeted theranostic applications. In turn, this approach supports the development of more reliable models. Background/Objective Pancreatic stellate cells (PSCs) in pancreatic adenocarcinoma (PDAC) are producing extracellular matrix, which promotes the formation of a dense fibrotic microenvironment. This makes PDAC a highly heterogeneous tumor-stroma-driven entity, associated with reduced perfusion, limited oxygen supply, high interstitial fluid pressure, and limited bioavailability of therapeutic agents. Methods In this study, spheroid and tumor xenograft models of human PSCs and PanC-1 cells were characterized radiopharmacologically using a combined positron emission tomography (PET) radiotracer approach. [18F]FDG, [18F]FMISO, and [18F]FAPI-74 were employed to monitor metabolic activity, hypoxic metabolic state, and functional expression of fibroblast activation protein alpha (FAPα), a marker of activated PSCs. Results In vitro, PanC-1 and multi-cellular tumor spheroids demonstrated comparable glucose uptake and hypoxia, whereas FAPα expression was significantly higher in PSC spheroids. In vivo, glucose uptake as well as the transition to hypoxia were comparable in PanC-1 and multi-cellular xenograft models. In mice injected with PSCs, FAPα expression decreased over a period of four weeks post-injection, which was attributed to the successive death of PSCs. In contrast, FAPα expression increased in both PanC-1 and multi-cellular xenograft models over time due to invasion of mouse fibroblasts. Conclusion The presented models are suitable for subsequently characterizing stromal cell-induced metabolic changes in tumors using noninvasive molecular imaging techniques. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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