RESUMO
More than two-thirds of cancer-related deaths are attributable to metastases. In some tumor types metastasis can occur up to 20 years after diagnosis and successful treatment of the primary tumor, a phenomenon termed late recurrence. Metastases arise from disseminated tumor cells (DTCs) that leave the primary tumor early on in tumor development, either as single cells or clusters, adapt to new environments, and reduce or shut down their proliferation entering a state of dormancy for prolonged periods of time. Dormancy has been difficult to track clinically and study experimentally. Recent advances in technology and disease modeling have provided new insights into the molecular mechanisms orchestrating dormancy and the switch to a proliferative state. A new role for epithelial-mesenchymal transition (EMT) in inducing plasticity and maintaining a dormant state in several cancer models has been revealed. In this review, we summarize the major findings linking EMT to dormancy control and highlight the importance of pre-clinical models and tumor/tissue context when designing studies. Understanding of the cellular and molecular mechanisms controlling dormant DTCs is pivotal in developing new therapeutic agents that prevent distant recurrence by maintaining a dormant state.
Assuntos
Neoplasias , Humanos , Transição Epitelial-MesenquimalRESUMO
Here, we describe a clinically relevant xenograft model of hormone receptor-positive breast cancer that maintains estrogen receptor (ER) status without the need for exogenous supplementation of hormones. The naturally low 17-ß-estradiol levels in host mice recapitulate levels seen in post-menopausal women. By introducing breast cancer cells directly into their "natural" microenvironment of the milk ducts, these cells maintain hormone receptor status, model the clinical progression of the disease, and develop ER- metastatic lesions or dormant micrometastatic lesions in the case of ER+ BC. With the use of GFP/RFP:Luc2 reporters, we can monitor in vivo tumour growth and conduct ex vivo metastases assays to evaluate dormant metastatic cell harboring organs. Upon recovery of metastatic cells from ER+ breast cancer models, downstream analyses can be conducted to assess the relationship between epithelial plasticity and metastatic dormancy.
Assuntos
Neoplasias da Mama , Modelos Animais de Doenças , Receptores de Estrogênio , Animais , Camundongos , Feminino , Neoplasias da Mama/patologia , Neoplasias da Mama/metabolismo , Humanos , Receptores de Estrogênio/metabolismo , Metástase Neoplásica , Linhagem Celular Tumoral , Microambiente Tumoral , Estradiol/metabolismo , Estradiol/farmacologiaRESUMO
More than 70% of human breast cancers (BCs) are estrogen receptor α-positive (ER+). A clinical challenge of ER+ BC is that they can recur decades after initial treatments. Mechanisms governing latent disease remain elusive due to lack of adequate in vivo models. We compare intraductal xenografts of ER+ and triple-negative (TN) BC cells and demonstrate that disseminated TNBC cells proliferate similarly as TNBC cells at the primary site whereas disseminated ER+ BC cells proliferate slower, they decrease CDH1 and increase ZEB1,2 expressions, and exhibit characteristics of epithelial-mesenchymal plasticity (EMP) and dormancy. Forced E-cadherin expression overcomes ER+ BC dormancy. Cytokine signalings are enriched in more active versus inactive disseminated tumour cells, suggesting microenvironmental triggers for awakening. We conclude that intraductal xenografts model ER + BC dormancy and reveal that EMP is essential for the generation of a dormant cell state and that targeting exit from EMP has therapeutic potential.
Assuntos
Neoplasias da Mama , Neoplasias de Mama Triplo Negativas , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal/genética , Feminino , Humanos , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismo , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/patologiaRESUMO
Targeting cancer stem cells (CSC) can serve as an effective approach toward limiting resistance to therapies. While basal-like (triple-negative) breast cancers encompass cells with CSC features, rational therapies remain poorly established. We show here that the receptor tyrosine kinase Met promotes YAP activity in basal-like breast cancer and find enhanced YAP activity within the CSC population. Interfering with YAP activity delayed basal-like cancer formation, prevented luminal to basal transdifferentiation, and reduced CSC. YAP knockout mammary glands revealed a decrease in ß-catenin target genes, suggesting that YAP is required for nuclear ß-catenin activity. Mechanistically, nuclear YAP interacted with ß-catenin and TEAD4 at gene regulatory elements. Proteomic patient data revealed an upregulation of the YAP signature in basal-like breast cancers. Our findings demonstrate that in basal-like breast cancers, ß-catenin activity is dependent on YAP signaling and controls the CSC program. These findings suggest that targeting the YAP/TEAD4/ß-catenin complex offers a potential therapeutic strategy for eradicating CSCs in basal-like breast cancers. SIGNIFICANCE: These findings show that YAP cooperates with ß-catenin in basal-like breast cancer to regulate CSCs and that targeting this interaction may be a novel CSC therapy for patients with basal-like breast cancer. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/8/2116/F1.large.jpg.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Células-Tronco Neoplásicas/metabolismo , Proteínas Proto-Oncogênicas c-met/metabolismo , Neoplasias de Mama Triplo Negativas/metabolismo , beta Catenina/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/antagonistas & inibidores , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Carcinogênese , Linhagem Celular Tumoral , Transdiferenciação Celular , Proteínas de Ligação a DNA/metabolismo , Feminino , Regulação Neoplásica da Expressão Gênica , Xenoenxertos , Humanos , Glândulas Mamárias Animais/citologia , Glândulas Mamárias Animais/metabolismo , Camundongos , Proteínas Musculares/metabolismo , Células-Tronco Neoplásicas/patologia , Proteômica , Fatores de Transcrição de Domínio TEA , Fatores de Transcrição/metabolismo , Neoplasias de Mama Triplo Negativas/patologia , Neoplasias de Mama Triplo Negativas/prevenção & controle , Neoplasias de Mama Triplo Negativas/terapia , Regulação para Cima , Proteínas Wnt/metabolismo , Proteínas de Sinalização YAP , beta Catenina/genéticaRESUMO
Many tumors display intracellular heterogeneity with subsets of cancer stem cells (CSC) that sustain tumor growth, recurrence, and therapy resistance. Cancer-associated fibroblasts (CAF) have been shown to support and regulate CSC function. Here, we investigate the interactions between CSCs and CAFs in mammary gland tumors driven by combined activation of Wnt/ß-catenin and Hgf/Met signaling in mouse mammary epithelial cells. In this setting, CSCs secrete the Hedgehog ligand SHH, which regulate CAFs via paracrine activation of Hedgehog signaling. CAFs subsequently secrete factors that promote expansion and self-renewal of CSCs. In vivo treatment of tumors with the Hedgehog inhibitor vismodegib reduce CAF and CSC expansion, resulting in an overall delay of tumor formation. Our results identify a novel intracellular signaling module that synergistically regulates CAFs and CSCs. Targeting CAFs with Hedgehog inhibitors may offer a novel therapeutic strategy against breast cancer. Cancer Res; 77(8); 2134-47. ©2017 AACR.