QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online 27 June 2007
doi: 10.1242/dev.02875

This Article Summary Full Text Full Text (PDF) Supplementary Material Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Strom, A. Articles by Herrera, P. L. Search for Related Content PubMed PubMed Citation Articles by Strom, A. Articles by Herrera, P. L.

Unique mechanisms of growth regulation and tumor suppression upon Apc inactivation in the pancreas

¹ Department of Genetic Medicine and Development, University of Geneva Faculty of Medicine, 1 Rue Michel-Servet, CH-1211 Geneva 4, Switzerland.
² Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel-Aviv University, Israel.
³ Department of Cell Biology, Cancer Institute, Tokyo 135-8550, Japan.
⁴ Unitat de Recerca en Biologia Cel·lular i Molecular (URBCM), Institut Municipal d'Investigació Mèdica (IMIM), Universitat Pompeu Fabra, Dr Aiguader, 88 08003 Barcelona, Spain.
⁵ Genetics and Stem Cell Laboratory, Swiss Institute for Experimental Cancer Research (ISREC), Ch. des Boveresses 155, CH-1066 Epalinges, Switzerland.
⁶ Division of Diabetes, Digestive and Kidney Disease, Division of Diabetes Metabolism and Endocrinology, Department of Clinical Molecular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
⁷ Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Life Sciences, CH-1015 Lausanne, Switzerland.

View larger version (39K): [in this window] [in a new window]   Fig. 1. Postnatal pancreatomegaly after Apc loss. (A) An E10.5 double-transgenic R26R;Pdx1-Cre+/- embryo stained with X-gal (whole mount). ß-galactosidase activity is detected both in the ventral and dorsal pancreatic buds. (B) Genomic PCR using DNA from tail biopsies, isolated acini, ducts or islets of 2-month-old control (+/+ and +/-) and ApcP-/- mice. Apc is efficiently recombined in all pancreatic cell types in ApcP-/- adults (300 bp band; unrecombined tissues yield a 1 kb-long PCR fragment). (C) Freshly dissected pancreas of 2-month-old ApcloxP/loxP (control) and ApcP-/- mice. (D) Pancreas:body-weight ratio. The pancreatic mass is increased in ApcP-/- mice (pancreatic weight: control, 0.39±0.108 g; ApcP-/-, 1.19±0.124 g). In total, six mice were analyzed per group; ***P<0.001. (E) Cell proliferation rate. The proliferation index was assayed with anti-BrdU or anti-Ki67 antibody, as indicated. White bars, controls; black bars, ApcP-/- mice (n=3 individuals per group; **P<0.01; *P<0.05). vp/dp, ventral/dorsal pancreatic primordia; s, stomach; d, duodenum; p, pancreas; sp, spleen. Scale bar: 0.5 cm in C.

View larger version (72K): [in this window] [in a new window]   Fig. 2. ß-catenin accumulates in ApcP-/- acinar cells. (A) Anti-pan ß-catenin immunofluorescence at E15.5, birth (P1), 1 month (confocal pictures are shown for this stage) and 12 months of age. In control mice (left column), ß-catenin staining is found in cell membranes at all stages analyzed. By contrast, in adult ApcP-/- mice (right column) staining for ß-catenin is mainly nuclear in acinar cells from P1 (open arrows) but remains peripheral in most islet and ductal cells, as in controls. Notice that some islet cells display a cytoplasmic ß-catenin staining (small arrow) in old ApcP-/- mice. (B) Western blot of total protein extracts from E15.5 and adult pancreata (50 µg per lane) using anti-unphosphorylated ß-catenin antibody and anti-ß-catenin-(phospho Y142) antibody. Unphosphorylated ß-catenin accumulates only in pancreatic extracts from ApcP-/- adult mice and is always undetectable in isolated islets (right). ß-catenin-(phospho Y142) is abundant in adult acini, but undetectable in developing primordia or in isolated islets (1-month-old), whether control or ApcP-/-. ß-tubulin and actin (lower row) show equal loading. d, duct; i, islet. Scale bars: 20 µm.

View larger version (49K): [in this window] [in a new window]   Fig. 3. Pancreatomegaly is c-myc dependent. (A) Freshly dissected pancreata from 2-month-old ApcP-/- and ApcP-/-;c-mycP-/- mice. Pancreatomegaly does not appear in the absence of the two c-myc alleles. (B) Anti-ß-catenin immunofluorescence on 2-month-old ApcP-/- and ApcP-/-;c-mycP-/- pancreatic sections. Notice the nuclear localization of ß-catenin in acinar cells of mice of both genotypes (open arrows). Islets are depicted with a dashed line. Paraffin sections were 5 µm thick. Small arrows show cytoplasmic ß-catenin in islets and ducts (d). (C) Western blot of total protein extracts from adult pancreas (50 µg per lane) using anti-unphosphorylated ß-catenin antibody. Unphosphorylated ß-catenin accumulates in the pancreas of ApcP-/-;c-mycP-/- mice, as in ApcP-/- animals. ß-tubulin shows equal loading. (D) ß-cell area in ApcP-/-;c-mycP-/- mice is similar to that of controls, whereas it is lower in ApcP-/- animals. A total of three mice were analyzed per group; *P<0.01. d, duodenum (A), duct (B); p, pancreas; sp, spleen. Scale bar: 0.5 cm in A; 20 µm in B.