The impact of acute inflammation on progression and metastasis in pancreatic cancer animal model

Abstract

Background: The impact of acute inflammation on cancer is unclear. Therefore, we evaluated the impact of acute inflammation on cancer progression in an animal model concerning morphological change as well as molecular features.

Material and methods: Murine pancreas ductal adenocarcinoma cell line (Panc-02) and zymosan were used for the induction of cancer and acute inflammation respectively, in C57/BL6 mice. In the C group (n = 10), 2 × 10⁷Panc02 cells were injected into the tail of the pancreas. In the Z1 (n = 10) and Z2 (n = 10), 3 mg of zymosan was injected intraperitoneally once and twice respectively, after tumor cell injection. All of the mice were sacrificed 4 weeks after tumor cell injection.

Results: The degree of inflammation was more severe in the Z2 group than in the other two groups. The tumor volume of the Z2 group was larger than that of the C group (P = 0.032) and the presence of liver metastasis was significantly more common in the Z2 group than in the C and Z1 groups (P = 0.025). Confocal microscopy analysis revealed significantly more expression of Snail, EpCAM, Muc1, NLRP3 and miR-155 in the liver and pancreas in the Z2 group than in the other two groups. EpCAM and Muc1 were detected in blood samples in the Z2 group by flow cytometry, but not in the other two groups. In the Z2, expression of E-Cadherin was weaker and vimentin, snail1 were stronger compared to the C and Z1 group in the PCR and western blot.

Conclusion: Present results suggest that acute inflammation accompanied with cancer promotes cancer progression by the epithelial-to-mesenchymal transition (EMT) and circulating tumor cells (CTC) process.

Keywords: Acute inflammation; Cancer; Circulating tumor cell; Epithelial-to-mesenchymal transition.