title: Transforming growth factor beta receptor type II inactivation induces the malignant transformation of intestinal neoplasms initiated by Apc mutation.
abstract: The transforming growth factor-beta (TGF-beta) signaling pathway is a tumor-suppressor pathway that is commonly inactivated in colon cancer. TGF-beta is a secreted ligand that mediates its effects through a transmembrane heteromeric receptor complex, which consists of type I (TGFBR1) and type II subunits (TGFBR2). Approximately 30% of colon cancers carry TGFBR2 mutations, demonstrating that it is a common target for mutational inactivation in this cancer. To assess the functional role of TGFBR2 inactivation in the multistep progression sequence of colon cancer, we generated a mouse model that recapitulates two common genetic events observed in human colon cancer by mating Apc(1638N/wt) mice with mice that are null for Tgfbr2 in the intestinal epithelium, Villin-Cre;Tgfbr2(E2flx/E2flx) mice. In this model, we observed a dramatic increase in the number of intestinal adenocarcinomas in the Apc(1638N/wt);Villin-Cre;Tgfbr2(E2flx/E2flx) mice (called Apc(1638N/wt);Tgfbr2(IEKO)) compared with those mice with intact Tgfbr2 (Apc(1638N/wt);Tgfbr2(E2flx/E2flx)). Additionally, in vitro analyses of epithelial tumor cells derived from the Apc(1638N/wt);Tgfbr2(IEKO) mice showed enhanced expression and activity of matrix metalloproteinase MMP-2 and MMP-9, as well as increased TGF-beta1 secretion in the conditioned medium. Similarly, primary tumor tissues from the Apc(1638N/wt);Tgfbr2(IEKO) mice also showed elevated amounts of TGF-beta1 as well as higher MMP-2 activity in comparison with Apc(1638N/wt);Tgfbr2(E2flx/E2flx)-derived tumors. Thus, loss of TGFBR2 in intestinal epithelial cells promotes the invasion and malignant transformation of tumors initiated by Apc mutation, providing evidence that Wnt signaling deregulation and TGF-beta signaling inactivation cooperate to drive the initiation and progression, respectively, of intestinal cancers in vivo.
authors.affiliation: Department of Cancer Biology, Vanderbilt University Medical School, Nashville, Tennessee, USA.
authors.forename: Nina M
authors.initials: NM
authors.lastname: Muñoz
authors.forename: Melissa
authors.initials: M
authors.lastname: Upton
authors.forename: Andres
authors.initials: A
authors.lastname: Rojas
authors.forename: M Kay
authors.initials: MK
authors.lastname: Washington
authors.forename: Li
authors.initials: L
authors.lastname: Lin
authors.forename: Anna
authors.initials: A
authors.lastname: Chytil
authors.forename: Elif G
authors.initials: EG
authors.lastname: Sozmen
authors.forename: Blair B
authors.initials: BB
authors.lastname: Madison
authors.forename: Ambra
authors.initials: A
authors.lastname: Pozzi
authors.forename: Randall T
authors.initials: RT
authors.lastname: Moon
authors.forename: Harold L
authors.initials: HL
authors.lastname: Moses
authors.forename: William M
authors.initials: WM
authors.lastname: Grady
mesh_terms: D000818:Animals; D048708:Cell Growth Processes / Q000502:physiology; D002471:Cell Transformation, Neoplastic / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D003110:Colonic Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D018450:Disease Progression; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D017491:Genes, APC; D007413:Intestinal Mucosa / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation; D009361:Neoplasm Invasiveness; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism
chemical_list: D018125:Receptors, Transforming Growth Factor beta; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II