RESUMEN
Tumour-associated fibroblasts (TAFs) are part of the tumour stroma, providing functional and structural support for tumour progression and development. The origin and biology of TAFs are poorly understood, but within the tumour environment, TAFs become activated and secrete different paracrine and autocrine factors involved in tumorigenesis. It has been shown that bone marrow mesenchymal stem cells (MSCs) can be recruited into the tumours, where they proliferate and acquire a TAF-like phenotype. We attempted to determine to what extent TAFs characteristics in vitro juxtapose to MSCs' definition, and we showed that TAFs and MSCs share immunophenotypic similarities, including the presence of certain cell surface molecules [human leukocyte antigen-DR subregion (HLA-DR), CD29, CD44, CD73, CD90, CD106 and CD117]; the expression of cytoskeleton and extracellular matrix proteins, such as vimentin, α-smooth muscle actin, nestin and trilineage differentiation potential (to adipocytes, chondrocytes and osteoblasts). When compared to MSCs, production of cytokines, chemokines and growth factors showed a significant increase in TAFs for vascular endothelial growth factor, transforming growth factor-ß1, interleukins (IL-4, IL-10) and tumour necrosis factor α. Proliferation rate was highly increased in TAFs and fibroblast cell lines used in our study, compared to MSCs, whereas ultrastructural details differentiated the two cell types by the presence of cytoplasmic elongations, lamellar content lysosomes and intermediate filaments. Our results provide supportive evidence to the fact that TAFs derive from MSCs and could be a subset of 'specialized' MSCs.
Asunto(s)
Células de la Médula Ósea/citología , Diferenciación Celular , Fibroblastos/patología , Células Madre Mesenquimatosas/citología , Actinas/metabolismo , Adipocitos/citología , Adipocitos/metabolismo , Células de la Médula Ósea/metabolismo , Células de la Médula Ósea/ultraestructura , Neoplasias de la Mama/patología , Línea Celular , Proliferación Celular , Células Cultivadas , Condrocitos/citología , Condrocitos/metabolismo , Femenino , Fibroblastos/metabolismo , Fibroblastos/ultraestructura , Antígenos HLA-DR/metabolismo , Humanos , Receptores de Hialuranos/metabolismo , Integrina beta1/metabolismo , Interleucina-1/metabolismo , Interleucina-10/metabolismo , Células Madre Mesenquimatosas/metabolismo , Células Madre Mesenquimatosas/ultraestructura , Microscopía Electrónica de Transmisión , Músculo Liso/química , Osteoblastos/citología , Osteoblastos/metabolismo , Factor de Crecimiento Transformador beta1/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Vimentina/metabolismoRESUMEN
Hematopoietic stem cells have a remarkable plastic capacity, which allows them to differentiate into various cells, such as immune cells, nervous cells, muscle cells, bone and cartilaginous cells. The aim of this study was to show the capacity of stem cells to differentiate into endothelial cells, in culture, after addition of endothelial cells growth supplement (ECGS). We also compared the behavior of these cells with that of endothelial cells obtained from human umbilical vein (HUVEC). CD34+ cells obtained by immunomagnetic separation from human umbilical cord and placental blood were used. After 12-15 days of culture in a medium containing ECGS, the cells showed morphological changes characteristic to endothelial cells and immunocytochemical analysis revealed the presence of CD31 surface antigen and von Willebrand factor. The flow-cytometric analysis of endothelial cells adhesion molecules (ECAM) showed that endothelial cells derived from CD34+ cells expressed CD54/ICAM-1 9.65+/-0.2% and CD106/VCAM 7.73+/-0.3%, values similar to those expressed by HUVECs. After TNF incubation, ECAM expression increased only in HUVECs. These data demonstrate that a fraction of circulating CD34+ cells may develop some endothelial cell characteristics when cultured with ECGS, but they are functionally different from HUVECs.
