RESUMO
Dermal fibroblasts deposit type I collagen, the dominant extracellular matrix molecule found in skin, during early postnatal development. Coincident with this biosynthetic program, fibroblasts proteolytically remodel pericellular collagen fibrils by mobilizing the membrane-anchored matrix metalloproteinase, Mmp14. Unexpectedly, dermal fibroblasts in Mmp14-/- mice commit to a large-scale apoptotic program that leaves skin tissues replete with dying cells. A requirement for Mmp14 in dermal fibroblast survival is recapitulated in vitro when cells are embedded within, but not cultured atop, three-dimensional hydrogels of crosslinked type I collagen. In the absence of Mmp14-dependent pericellular proteolysis, dermal fibroblasts fail to trigger ß1 integrin activation and instead actuate a TGF-ß1/phospho-JNK stress response that leads to apoptotic cell death in vitro as well as in vivo. Taken together, these studies identify Mmp14 as a requisite cell survival factor that maintains dermal fibroblast viability in postnatal dermal tissues.
Assuntos
Apoptose , Sobrevivência Celular , Fibroblastos , Metaloproteinase 14 da Matriz , Animais , Metaloproteinase 14 da Matriz/metabolismo , Metaloproteinase 14 da Matriz/genética , Fibroblastos/metabolismo , Camundongos , Camundongos Knockout , Colágeno Tipo I/metabolismo , Colágeno Tipo I/genética , Integrina beta1/metabolismo , Integrina beta1/genética , Fator de Crescimento Transformador beta1/metabolismo , Derme/metabolismo , Derme/citologia , Células Cultivadas , Matriz Extracelular/metabolismo , Camundongos Endogâmicos C57BL , Pele/metabolismoRESUMO
3D tissue culture models are utilized to study breast cancer and other pathologies because they better capture the complexity of in vivo tissue architecture compared to 2D models. However, to mimic the in vivo environment, the mechanics and geometry of the ECM must also be considered. Here, we studied the mechanical environment created in two 3D models, the overlay protocol (OP) and embedded protocol (EP). Mammary epithelial acini features were compared using OP or EP under conditions known to alter acinus organization, i.e. collagen crosslinking and/or ErbB2 receptor activation. Finite element analysis and active microrheology demonstrated that OP creates a physically asymmetric environment with non-uniform mechanical stresses in radial and circumferential directions. Further contrasting with EP, acini in OP displayed cooperation between ErbB2 signalling and matrix crosslinking. These differences in acini phenotype observed between OP and EP highlight the functional impact of physical symmetry in 3D tissue culture models.
Assuntos
Modelos Biológicos , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Técnicas de Cultura de Células , Linhagem Celular Tumoral , Movimento Celular , Colágeno/química , Combinação de Medicamentos , Matriz Extracelular/química , Matriz Extracelular/metabolismo , Feminino , Análise de Elementos Finitos , Humanos , Laminina/química , Pinças Ópticas , Fenótipo , Proteoglicanas/química , Receptor ErbB-2/química , Receptor ErbB-2/metabolismo , Reologia , Transdução de Sinais , Estresse MecânicoRESUMO
In vitro, topographical and biophysical cues arising from the extracellular matrix (ECM) direct skeletal stem cell (SSC) commitment and differentiation. However, the mechanisms by which the SSC-ECM interface is regulated and the outcome of such interactions on stem cell fate in vivo remain unknown. Here we demonstrate that conditional deletion of the membrane-anchored metalloproteinase MT1-MMP (Mmp14) in mesenchymal progenitors, but not in committed osteoblasts, redirects SSC fate decisions from osteogenesis to adipo- and chondrogenesis. By effecting ECM remodeling, MT1-MMP regulates stem cell shape, thereby activating a ß1-integrin/RhoGTPase signaling cascade and triggering the nuclear localization of the transcriptional coactivators YAP and TAZ, which serve to control SSC lineage commitment. These data identify a critical MT1-MMP/integrin/YAP/TAZ axis operative in the stem cell niche that oversees SSC fate determination.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Integrina beta1/metabolismo , Metaloproteinase 14 da Matriz/metabolismo , Fosfoproteínas/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismo , Aciltransferases , Proteínas Adaptadoras de Transdução de Sinal/genética , Adipogenia , Animais , Células da Medula Óssea/metabolismo , Proteínas de Ciclo Celular , Linhagem da Célula , Núcleo Celular/genética , Núcleo Celular/metabolismo , Forma Celular , Células Cultivadas , Condrogênese , Matriz Extracelular/genética , Matriz Extracelular/metabolismo , Técnicas de Introdução de Genes , Humanos , Metaloproteinase 14 da Matriz/genética , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Osteogênese , Fenótipo , Fosfoproteínas/genética , Proteólise , Nicho de Células-Tronco , Fatores de Transcrição/genética , Ativação Transcricional , Proteínas de Sinalização YAPRESUMO
Breast cancer remains one of the leading causes of death among women across the world. The last few decades have seen significant reduction in mortality owing to earlier detection and better adjuvant treatments that were developed based on clinical staging and morphological features. As these treatments have evolved, the heterogeneity of breast cancer poses a new challenge, since there is no standard gold-therapy suitable for all tumors of the mammary gland. Therefore, contemporary management and research efforts are directed toward specific prognostic and predictive molecular signatures that can guide targeted individualized therapy. The goal of ongoing research in this field is to identify specific molecular targets for developing novel therapeutic approaches. These targets can also serve to improve screening of breast cancer. This review focuses on the role of cancer testis antigens (CTAs) in breast carcinogenesis and explores the potential for development of targeted screening and therapeutic approaches. Normally found in the testes, these antigens are highly correlative with cancers of the breast, skin, and ovaries. These implications have been further corroborated through uncovering the interaction of CTAs with genes and proteins involved in tumor suppression and homeostasis like p53. There is some evidence that these genes can be targeted for early detection in addition to being candidates for cancer immunotherapy.