Modeling AEC-New Approaches to Study Rare Genetic Disorders
AMERICAN JOURNAL OF MEDICAL GENETICS PART A
Authors: Koch, Peter J.; Dinella, Jason; Fete, Mary; Siegfried, Elaine C.; Koster, Maranke I.
Abstract
Ankyloblepharon-ectodermal defects-cleft lip/palate (AEC) syndrome is a rare monogenetic disorder that is characterized by severe abnormalities in ectoderm-derived tissues, such as skin and its appendages. A major cause of morbidity among affected infants is severe and chronic skin erosions. Currently, supportive care is the only available treatment option for AEC patients. Mutations in TP63, a gene that encodes key regulators of epidermal development, are the genetic cause of AEC. However, it is currently not clear how mutations in TP63 lead to the various defects seen in the patients' skin. In this review, we will discuss current knowledge of the AEC disease mechanism obtained by studying patient tissue and genetically engineered mouse models designed to mimic aspects of the disorder. We will then focus on new approaches to model AEC, including the use of patient cells and stem cell technology to replicate the disease in a human tissue culture model. The latter approach will advance our understanding of the disease and will allow for the development of new in vitro systems to identify drugs for the treatment of skin erosions in AEC patients. Further, the use of stem cell technology, in particular induced pluripotent stem cells (iPSC), will enable researchers to develop new therapeutic approaches to treat the disease using the patient's own cells (autologous keratinocyte transplantation) after correction of the disease-causing mutations. (C) 2014 Wiley Periodicals, Inc.
Distinct Expression Profiles of p63 Variants during Urothelial Development and Bladder Cancer Progression
AMERICAN JOURNAL OF PATHOLOGY
Authors: Karni-Schmidt, Orit; Castillo-Martin, Mireia; Shen, Tian Huai; Gladoun, Nataliya; Domingo-Domenech, Josep; Sanchez-Carbayo, Marta; Li, Yingchun; Lowe, Scott; Prives, Carol; Cordon-Cardo, Carlos
Abstract
The TP63 gene, a member of the TP53 tumor suppressor gene family, can be expressed as at least six isoforms due to alternative promoter use and alternative splicing. The lack of p63 isoform-specific antibodies has limited the analysis of the biological significance of p63. We report a novel set of well-defined antibodies to examine p63 isoforms in mouse and human urothelium during embryogenesis and tumor progression, respectively. We provide evidence that basal and intermediate urothelial cells express p63 isoforms, with the TAp63 variant the first to be detected during development, whereas umbrella cells are characterized by a p63-negative phenotype. Notably, we report that p63-null mice develop a bladder with an abnormal urothelium, constituted by a single layer of cells that express uroplakin II and low molecular weight cytokeratins, consistent with an umbrella cell phenotype. Finally, analysis of 202 human bladder carcinomas revealed a new categorization of invasive tumors into basal-like (positive for Delta Np63 and high molecular weight cytokeratins and negative for low molecular weight cytokeratins) versus luminal-like (negative for Delta Np63 and high molecular weight cytokeratins and positive for low molecular weight cytokeratins) phenotypes, with Delta Np63 expression associated with an aggressive clinical course and poor prognosis. This study highlights the relevance of p63 isoforms in both urothelial development and bladder carcinoma progression, with Delta Np63 acting as an oncogene in certain invasive bladder tumors. (Am J Pathol 2011, 178:1350-1360; DOI: 10.1016/j.ajpath.2010.11.061)