Fig 1.
Hyperplasia of α-like cells and neuroendocrine tumors in the GCGKO mouse model.
H&E-staining (A–J) and fluorescent immunohistochemical analyses (K–T) of the pancreas. Sections of pancreas from 2-month-old (A, F, K, and P), 5-month-old (B, G, L, and Q), 8-month-old (C, H, M, and R) and 12–15-month-old (D, I, N, and S) GCGKO mice and from 15-month-old Gcggfp/+ mice (E, J, O, and T) are shown. Immunoreactivity for insulin is red, and the fluorescent signal generated by GFP is green. Scale bars: 200 μm.
Fig 2.
Macroscopic images of the tumor and disseminated tumor cells.
A–C: Macroscopic images of abdominal organs from an 18-month-old control mouse (A) and a 15-month-old GCGKO (B and C) mouse. Pancreatic tumors are indicated by yellow arrow heads and macroscopic liver tumors by red arrow heads. D and E: Images of dissected pancreas and spleen. Brightfield (D) and fluorescent (E) images are shown. Scale bars: 10 mm (in A–D). F–I: Fluorescent images of the tumor and disseminated GFP-positive cells. Macroscopic tumors in the pancreas (F) and liver (G), and microscopic dissemination of GFP-positive cells in the liver (H) and lungs (I). Scale bars: 2.5 mm (in F–I).
Table 1.
Macroscopic characteristics of the tumors.
Fig 3.
Neuroendocrine tumors in the pancreas of 15-month-old GCGKO mice.
A–D: H&E-staining (A and B) and immunohistochemical analysis of synaptophysin expression (C and D) in the tumor. E–P: Fluorescent immunohistochemical analyses showing the GFP fluorescent signal (F, H, J, L, N, and P) or not (E, G, I, K, M, and O). Immunoreactivity for insulin (E and F), somatostatin (G and H), pancreatic polypeptide (I and J), chromogranin A (K and L), VEGF (M and N), and Ki-67 (O and P) is shown in red. Scale bars: 200 μm.
Fig 4.
Dissemination of GFP-positive cells and metastatic neuroendocrine tumors in the liver of GCGKO mice.
A and B: Fluorescence with phase contrast imaging of the liver section. Livers from a 12-month-old GCGKO mouse (A) and an 18-month-old Gcggfp/+ mouse (B) are shown. C and D: H&E-staining of the metastatic neuroendocrine tumor. E–P: Fluorescent immunohistochemical analyses showing the GFP fluorescent signal (F, H, J, L, N, and P) or not (E, G, I, K, M, and O). Immunoreactivity for insulin (E and F), somatostatin (G and H), pancreatic polypeptide (I and J), chromogranin A (K and L), VEGF (M and N), and Ki-67 (O and P) is shown in red. Scale bars: 200 μm.
Fig 5.
Gene expression in the islets and tumors.
Relative expression levels of the indicated genes normalized to ß-actin are shown. Expression levels in control islets are set as 1. Data represent the mean±SD. N = 4–8 (islets: 6, panNET: 8, and metastatic tumor in liver: 4).
Fig 6.
Subrenal capsule transplantation of the pancreatic neuroendocrine tumors.
Tumor grafts were transplanted into GCGKO (A–D) and control Gcggfp/+ mice (E–H) and analyzed 4 weeks after transplantation. Macroscopic (A and E) and fluorescent (B and F) images of the kidney are shown. Scale bars: 2.5 mm. H&E-staining (C and G) and fluorescent immunohistochemistry for Ki67 (D and H) are shown. Ki-67 immunoreactivity is red, and GFP fluorescence is green. Scale bars: 200 μm. (I) Ki-67 index of the transplants in GCGKO and control mice. Data represent the mean±SD. N = 6 (GCGKO) and 4 (control).