Fig. 1.

Design and development of the experimental model. a Three different GFP-RENCA implantation-extraction modalities were used to develop increasingly aggressive cancer cell lines: orthotopic implantation and extraction from primary tumors generated Kidney Primary Tumor cell lines (KPT); orthotopic implantation and extraction from lung metastases generated Kidney-to-Lung-Metastases cell lines (K-LM); injection into tail vein and extraction from lung metastases generated Tail-to-Lung-Metastases cell lines (T-LM). b Scheme of different tumor progression phases whose biological mechanisms are expected to be revealed by the generated cancer cell lines. c Immunofluorescence analysis of tumor- or lung metastases-explanted GFP-RENCA showing the absence of GFP-negative stromal cells after 14 days in culture. All cells were counter-stained with both Alexa Flour 568 phalloidin and DAPI. Scale bars, 100 μm. Pn, number of cell passage in vivo