Volume 122, Issue 2, Pages 428-437 (February 2002) Expression of CCK2 receptors in the murine pancreas: Proliferation, transdifferentiation of acinar cells, and neoplasia  Pascal Clerc, Stéphane Leung–Theung–Long, Timothy C. Wang, Graham J. Dockray, Michèle Bouisson, Marie–Bernadette Delisle, Nicole Vaysse, Lucien Pradayrol, Daniel Fourmy, Marlène Dufresne  Gastroenterology  Volume 122, Issue 2, Pages 428-437 (February 2002) DOI: 10.1053/gast.2002.30984 Copyright © 2002 American Gastroenterological Association Terms and Conditions

Fig. 1 Growth curves of the pancreas. (A) At each indicated developmental stage, 8–10 ElasCCK2 (•) and B6SJLF1 control (○) mice were killed and their pancreas removed and weighed. (B) Same measures were performed with INS-GAS (□) and ElasCCK2 × INS-GAS (■) mice. Growth rates were determined as the slopes of growth curves. Results represent the mean ± SEM of pancreas weight. Gastroenterology 2002 122, 428-437DOI: (10.1053/gast.2002.30984) Copyright © 2002 American Gastroenterological Association Terms and Conditions

Fig. 2 Morphometric analysis. (A) The amount of pancreatic exocrine tissue was calculated at each age as indicated in Materials and Methods. (B) Acinar cell proliferation rates. Data are represented as percentage of BrdU-positive acinar cells. Positive cells were counted in each pancreas for 4 control and ElasCCK2 mice; at least 1500 positive cells were counted in each pancreas. (C) The size of acinar cells was measured as the mean cross-sectional area in the pancreas of 26-day-old animals. Results are expressed as means ± SEM; significance at *P < 0.05 and ***P < 0.01. ■ and E, ElasCCK2 mice; □ and C, nontransgenic B6SJLF1 mice. Gastroenterology 2002 122, 428-437DOI: (10.1053/gast.2002.30984) Copyright © 2002 American Gastroenterological Association Terms and Conditions

Fig. 3 Histologic analysis of transgenic mice pancreas. H&E staining of sections of (A–C) ElasCCK2, (D and E) ElasCCK2 × INS-GAS, and (F) control mice. (A) Eosinophilic acinar cells in the pancreas of a 9-month-old ElasCCK2 mouse; entire lobules are eosinophilic (original magnification 20×). (B) Loss of normal architecture in the pancreas of a 9-month-old ElasCCK2 mouse; acinar cells and nuclei are not homogeneous in size (arrowheads), and some cells are binucleated (arrows) (original magnification 100×). (C) Acini of this pancreatic lobule in a 77-day-old ElasCCK2 mouse undergo dedifferentiation into ductular structures (arrow); the arrowhead depicts adipose replacement of acini (original magnification 40×). (D) Ductal metaplasia in the pancreas of a 30-day-old ElasCCK2 × INS-GAS mouse (original magnification 40×). (E) Ductal hyperplasia in the pancreas of a 30-day-old ElasCCK2 × INS-GAS mouse (original magnification 40×). (F) Control pancreas (original magnification 20×). Gastroenterology 2002 122, 428-437DOI: (10.1053/gast.2002.30984) Copyright © 2002 American Gastroenterological Association Terms and Conditions

Fig. 4 RT-PCR of total RNA from ElasCCK2 mice pancreas at 10 days old (lanes 2 and 8), 25 days old (lanes 3 and 9), 40 days old (lanes 4 and 10), 55 days old (lanes 5 and 11), and 90 days old (lanes 6 and 12) using primers specific of the murine CCK1 receptor sequence (lanes 2 to 6) and primers specific of the human CCK2/gastrin receptor sequence (lanes 8 to 12). Standards shown on the figure are 1605-, 1198-, 676-, 517-, 460-, and 396-base pair fragments of pGEM markers. Gastroenterology 2002 122, 428-437DOI: (10.1053/gast.2002.30984) Copyright © 2002 American Gastroenterological Association Terms and Conditions

Fig. 5 Osteoclast-like giant cell tumor of an ElasCCK2 mouse pancreas. (A) H&E staining showing giant cells containing more than 20 nuclei and ducts interspaced with a few spindle and pleomorphic mononuclear cells. Note the round to ovoid nuclei that vary in size in the duct (original magnification 40×). (B) H&E staining of the transitional area between the pancreatic tissue and the tumor. This region is characterized by mononuclear cells infiltrating the adjacent nontumoral pancreas that appears largely disorganized. There is also focal ductal hyperplasia (arrow) and ductal metaplasia (arrowhead) (original magnification 20×). (C) Anticytokeratin antibody stains cells in the tumoral area (original magnification 20×). (D) Amylase is strongly expressed in the cytoplasm of adjacent acinar cells but not in the tumor except in isolated cells (arrow) and in duct-like structure (arrowhead) (original magnification 20×). (E) Higher magnification of a duct-like structure partially stained with the antiamylase antibody (original magnification 100×). (F) Expression of the CCK2 receptor on the basal membrane of the peritumoral acinar cells (original magnification 40×) but not in the tumor (G) (original magnification 40×). (H) Staining of the transitional area shows faintly stained or unstained cells in acini (arrow) and tubular complexes (arrowhead) (original magnification 40×). Gastroenterology 2002 122, 428-437DOI: (10.1053/gast.2002.30984) Copyright © 2002 American Gastroenterological Association Terms and Conditions

Fig. 6 Acinar cell carcinoma of an ElasCCK2 mouse pancreas. (A) H&E staining of the pancreas shows disorganization of the pancreatic lobules, increased inter- and intralobular fibrosis, and a nodule that is separated by a fibrous capsule and composed of acinar cells (arrows) embedded in a fibrotic stroma forming at the edge of the pancreas (original magnification 4×). (B) Higher magnification of a nodule showing pleomorphic and disorganized acini with nuclei that are irregular in size (original magnification 40×). (C) PAS staining of the tumor. Periphery of the tumor contains tubular complexes that may contain mucus (arrows). Note the progressive enlargement of the acinar lumen and the replacement of acinar cells by columnar cells forming a duct-like structure (original magnification 40×). (D) Anticytokeratin staining of tubular complexes (original magnification 40×). (E) Partial amylase immunoreactivity in some cells of the tubular complexes (arrows) (original magnification 100×). (F) Anti-CCK2/gastrin antibody partially stains tubular complexes (original magnification 40×). Gastroenterology 2002 122, 428-437DOI: (10.1053/gast.2002.30984) Copyright © 2002 American Gastroenterological Association Terms and Conditions

Fig. 7 Proliferative foci in ElasCCK2 × INS-GAS mice. (A) H&E staining showing 2 adjacent pancreatic lobules. Upper lobule (PF, proliferative foci) exhibits a higher density of nuclei, increased nuclear size, and prominent nucleoli compared with normal adjacent lobule (NP, normal pancreas) (original magnification 20×). (B) BrdU immunoreactivity shows that many nuclei of upper lobule are stained (original magnification 20×). Gastroenterology 2002 122, 428-437DOI: (10.1053/gast.2002.30984) Copyright © 2002 American Gastroenterological Association Terms and Conditions