LC-MS/MS analysis of gemcitabine and its metabolites in primary murine pancreatic tumors and liver metastases

E Hessmann; K Frese; T Bapiro; D Jodrell; T Gress; D Tuveson; V Ellenrieder; A Neesse

doi:10.1055/s-0035-1559093

Zeitschrift für Gastroenterologie, Inhaltsverzeichnis

LC-MS/MS analysis of gemcitabine and its metabolites in primary murine pancreatic tumors and liver metastases

E Hessmann ¹, K Frese ², T Bapiro ³, D Jodrell ³, T Gress ⁴, D Tuveson ⁵, V Ellenrieder ¹, A Neesse ¹

¹Gastroenterologie und gastrointestinale Onkologie, Universitätsmedizin Göttingen, Göttingen, Deutschland
²Princess Margaret Cancer Center, Toronto, Kanada
³Li Ka Shing Centre, Cambridge Cancer Research Institute, Cancer Research UK, Cambridge, Vereinigtes Königreich
⁴Gastroenterologie, Endokrinologie, Stoffwechsel und Infektiologie, Universitätsklinik Marburg, Marburg, Deutschland
⁵Pancreatic Cancer Research Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, Vereinigte Staaten

Abstract

Introduction: Impaired drug delivery is a common feature in pancreatic ductal adenocarcinoma (PDA) that may determine clinical response in patients. However, drug uptake and clearance are highly variable between tumours. For individualized treatment strategies it may be important to analyse drug delivery of chemotherapeutic agents from small tissue biopsies to identify this variability between tumours. To investigate whether liver metastases may serve as a surrogate tissue for drug delivery and metabolism, we analysed gemcitabine metabolites, stromal composition, and vascular density in primary pancreatic tumours and liver metastases in a genetically engineered mouse model.

Material and Methods: The LSL-KrasG12D/+;LSL-Trp53R172 H/+;Pdx-1-Cre (KPC) mouse model was used. Gemcitabine was administered at 100 mg/kg by intraperitoneal (i.p.) injections. Primary tumor and liver metastases were harvested 2h after gemcitabine administration. Fresh frozen samples from murine pancreatic tumors (n = 15), liver metastasis (n = 15) and normal liver (n = 15) were processed and analyzed by LC-MS/MS to measure the concentration of gemcitabine (dFdC), dFdU and gemcitabine triphosphate (dFdCTP), respectively. In a separate cohort of KPC mice, immunohistochemistry was performed on formalin fixed paraffin embedded tissues of primary pancreatic tumors (n = 6) and corresponding liver metastases (n = 6) for various stromal markers, CD31 and cytidine deaminase (CDA).

Results: The stromal composition of the primary tumor and the corresponding liver metastasis was similar and did not reveal dramatic differences. The parent drug dFdC was significantly higher in pancreatic tumors compared to liver metastases (p < 0.05) and normal liver tissue (p < 0.02). The concentration of dFdU showed no significant difference between groups, but the concentration of the activate metabolite, dFdCTP, was significantly higher in primary tumor tissue compared to liver metastases (p < 0.04) and normal liver tissue (p < 0.003).

Conclusions: Despite comparable stromal composition and mean vessel density of murine pancreatic tumors and their respective liver metastases, we found significant differences in gemcitabine pharmacokinetics between liver metastases and matched primary pancreatic tumors.