Figure 4: N-cadherin-expressing tumors evade gemcitabine treatment in a pancreatic cancer orthotopic mouse model.

A. Schematic representation of pancreatic orthotopic mouse tumor study for the evaluation of N-cadherin or EpCAM effects on gemcitabine therapy. PANC-1, PANC-1 overexpressing N-cadherin, or PANC-1 overexpressing EpCAM cells were orthotopically injected into the pancreas of immunodeficient female nude mice and gemcitabine treatment initiated two weeks after the engraftment procedure for the duration of the study. After 12 weeks, all mice were euthanized, and tumor burden and metastases incidence were evaluated ex vivo. B. Representative primary tumor from each group showing relative size and quantification of tumor volume and weight; OE, overexpression. Bars, mean ± SEM (n=5/group) C. Mouse necropsies showing primary tumors in pancreas (green arrows) and metastatic nodules in secondary sites (yellow arrows.) D. Bar graph shows average number of metastatic nodules in vital abdominal organs E. Immunohistochemical analysis of hENT1 was performed for primary tumors. Representative images of hENT1 (red) expression and nuclear counterstain DAPI (blue) in different groups (left) and zoomed in to show detail (right). Bar, 100 μm. Zoom bar, 10 μm. F. Immunohistochemical analysis in primary tumors for hENT1 (red) and EpCAM (green) (left) or hENT1 (red) and N-cadherin (green) (right) with merged images depicting coexpression (yellow). Bar, 100 μm. Statistical analyses performed with two-tailed Student’s t-test. *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001