PTEN Loss in E-Cadherin-Deficient Mouse Mammary Epithelial Cells Rescues Apoptosis and Results in Development of Classical Invasive Lobular Carcinoma

Cell Rep. 2016 Aug 23;16(8):2087-2101. doi: 10.1016/j.celrep.2016.07.059. Epub 2016 Aug 11.

Abstract

Invasive lobular carcinoma (ILC) is an aggressive breast cancer subtype with poor response to chemotherapy. Besides loss of E-cadherin, a hallmark of ILC, genetic inactivation of PTEN is frequently observed in patients. Through concomitant Cre-mediated inactivation of E-cadherin and PTEN in mammary epithelium, we generated a mouse model of classical ILC (CLC), the main histological ILC subtype. While loss of E-cadherin induced cell dissemination and apoptosis, additional PTEN inactivation promoted cell survival and rapid formation of invasive mammary tumors that recapitulate the histological and molecular features, estrogen receptor (ER) status, growth kinetics, metastatic behavior, and tumor microenvironment of human CLC. Combined inactivation of E-cadherin and PTEN is sufficient to cause CLC development. These CLCs showed significant tumor regression upon BEZ235-mediated inhibition of PI3K signaling. In summary, this mouse model provides important insights into CLC development and suggests inhibition of phosphatidylinositol 3-kinase (PI3K) signaling as a potential therapeutic strategy for targeting CLC.

Keywords: BEZ235; Cre-lox; E-cadherin; PTEN; breast cancer; classical invasive lobular carcinoma; genetically engineered mouse model; metastasis; tumor microenvironment.

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology
  • Cadherins / deficiency
  • Cadherins / genetics*
  • Carcinoma, Lobular / drug therapy
  • Carcinoma, Lobular / genetics*
  • Carcinoma, Lobular / mortality
  • Carcinoma, Lobular / pathology
  • Cell Line, Tumor
  • Cell Survival
  • Female
  • Gene Expression Profiling
  • Gene Expression Regulation, Neoplastic*
  • Gene Silencing*
  • Imidazoles / pharmacology
  • Integrases / genetics
  • Integrases / metabolism
  • Mammary Neoplasms, Experimental / drug therapy
  • Mammary Neoplasms, Experimental / genetics*
  • Mammary Neoplasms, Experimental / mortality
  • Mammary Neoplasms, Experimental / pathology
  • Mice
  • Mice, Knockout
  • Neoplasm Invasiveness
  • PTEN Phosphohydrolase / deficiency
  • PTEN Phosphohydrolase / genetics*
  • Phosphatidylinositol 3-Kinases / genetics
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphoinositide-3 Kinase Inhibitors*
  • Quinolines / pharmacology
  • Receptors, Estrogen / genetics
  • Receptors, Estrogen / metabolism
  • Signal Transduction
  • Survival Analysis
  • Tumor Microenvironment

Substances

  • Antineoplastic Agents
  • Cadherins
  • Cdh1 protein, mouse
  • Imidazoles
  • Phosphoinositide-3 Kinase Inhibitors
  • Quinolines
  • Receptors, Estrogen
  • Cre recombinase
  • Integrases
  • PTEN Phosphohydrolase
  • Pten protein, mouse
  • dactolisib