RESUMO
The claudin-low subtype is a recently identified rare molecular subtype of human breast cancer that expresses low levels of tight and adherens junction genes and shows high expression of epithelial-to-mesenchymal transition (EMT) genes. These tumors are enriched in gene expression signatures derived from human tumor-initiating cells (TICs) and human mammary stem cells. Through cross-species analysis, we discovered mouse mammary tumors that have similar gene expression characteristics as human claudin-low tumors and were also enriched for the human TIC signature. Such claudin-low tumors were similarly rare but came from a number of distinct mouse models, including the p53 null transplant model. Here we present a molecular characterization of 50 p53 null mammary tumors compared with other mouse models and human breast tumor subtypes. Similar to human tumors, the murine p53 null tumors fell into multiple molecular subtypes, including two basal-like, a luminal, a claudin-low, and a subtype unique to this model. The claudin-low tumors also showed high gene expression of EMT inducers, low expression of the miR-200 family, and low to absent expression of both claudin 3 and E-cadherin. These murine subtypes also contained distinct genomic DNA copy number changes, some of which are similarly altered in their cognate human subtype counterpart. Finally, limiting dilution transplantation revealed that p53 null claudin-low tumors are highly enriched for TICs compared with the more common adenocarcinomas arising in the same model, thus providing a unique preclinical mouse model to investigate the therapeutic response of TICs.
Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Genômica/métodos , Neoplasias Mamárias Animais/genética , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Adenocarcinoma/classificação , Adenocarcinoma/genética , Adenocarcinoma/patologia , Animais , Neoplasias da Mama/classificação , Claudinas/metabolismo , Análise por Conglomerados , Variações do Número de Cópias de DNA/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Genes Neoplásicos/genética , Genoma Humano/genética , Humanos , Neoplasias Mamárias Animais/classificação , Neoplasias Mamárias Animais/patologia , Camundongos , MicroRNAs/metabolismo , Transplante de Neoplasias , Proteína Supressora de Tumor p53/deficiência , Proteína Supressora de Tumor p53/metabolismoRESUMO
Lysophosphatidic acid (LPA) acts through high-affinity G protein-coupled receptors to mediate a plethora of physiological and pathological activities associated with tumorigenesis. LPA receptors and autotaxin (ATX/LysoPLD), the primary enzyme producing LPA, are aberrantly expressed in multiple cancer lineages. However, the role of ATX and LPA receptors in the initiation and progression of breast cancer has not been evaluated. We demonstrate that expression of ATX or each edg family LPA receptor in mammary epithelium of transgenic mice is sufficient to induce a high frequency of late-onset, estrogen receptor (ER)-positive, invasive, and metastatic mammary cancer. Thus, ATX and LPA receptors can contribute to the initiation and progression of breast cancer.
