PO-204 The contribution of epithelial to mesenchymal transition (EMT) to the metastases of pancreatic cancer
Year: 2018
Type: conference-abstract
Abstract: Introduction The role of epithelial to mesenchymal transition in metastatic processes remains a controversial field. While EMT is easily accessible in vitro , tracking EMT cells in vivo has been difficult for a long time. Therefore we created a dual recombinase, dual fluorescence reporter system which can monitor EMT and non-EMT related processes in vivo . Material and methods Pdx1-Flp; FSF-Kras G12D ; Fsp1-Cre ; genotypes with two different fluorescence reporter systems ( R26 mTmG or R26 Ai-65-tdTom ) were used to specifically induce pancreatic cancer and label EMT events in vivo. R26 mTmG labels unrecombined cells with a red fluorochrome (tomato) while cre-recombined cells express a green fluorescence protein (eGFP). The R26 Ai-65-tdTom reporter only labels Flp and Cre recombined cells with tomato. To monitor EMT events Fsp1 (S100A4) was administered to control the activation of Cre. Fsp1 plays a major role in the early stages of EMT and is normally non present in pancreatic tumour cells. An activation of Fsp1 – and therefore EMT induction – leads to a change in the fluorescence properties of the reporters as mentioned above. In addition, this change is irreversible, so a backswitch of the cell via mesenchymal to epithelial transition (MET) won‘t influence the signal. Orthotopic transplantation of primary pancreatic tumour (PPT) cells into immunocompetent (wildtype C57BL/6 ) and immunodeficience ( NOD/SCID IL2Rγnull (NSG) ) mice were performed to further investigate metastatic patterns and the influence of the immune system. Analyses of tumour, disseminated and metastatic cells via immunofluorescence staining and FACS were performed. Results and discussions We observed recombined (R) and non recombined (NR) metastases in all our experimental settings (endogenous; implanted - wildtype and immunodeficient - mice). Interestingly the ratio of R to NR metastases changed according to the organ (e.g. 10:2 in lungs; 1:10 in lymphnodes). Suprisingly, the amount of NR metastases (non-EMT) in total were significantly higher than recombined (75% NR). On a side note we found that the recombined (EMT) tumour cells were much more likely to become circulating tumour cells (CCTs). A 5- to 50-fold increase of the recombined cell percentage was observed in the blood compared to the PPT. Conclusion The data suggest that there might be an EMT but also a non-EMT route to form metastases. Those routes seem to coexist and are to some point organ-specific. Also, there was no evidence for the amount of CCTs to predict the metastases pattern.
Source: ESMO Open
Authors: Q. Müller, K. Schuck, A. Kroemer, D. Saur
Institutions: TUM Klinikum, Technical University of Munich
Language: English
Topic: Cancer Cells and Metastasis
Subfield: Oncology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,910
OpenAlex ID: W2811153719