RESUMEN
Recently, we reported that the histone methyltransferase, EZH2, controls leukocyte migration through interaction with the cytoskeleton remodeling effector, VAV, and direct methylation of the cytoskeletal regulatory protein, Talin. However, it is unclear whether this extranuclear, epigenetic-independent function of EZH2 has a profound impact on the initiation of cellular transformation and metastasis. Here, we show that EZH2 increases Talin1 methylation and cleavage, thereby enhancing adhesion turnover and promoting accelerated tumorigenesis. This transforming capacity is abolished by targeted disruption of EZH2 interaction with VAV. Furthermore, our studies demonstrate that EZH2 in the cytoplasm is closely associated with cancer stem cell properties, and that overexpression of EZH2, a mutant EZH2 lacking its nuclear localization signal (EZH2ΔNLS), or a methyl-mimicking Talin1 mutant substantially promotes JAK2-dependent STAT3 activation and cellular transformation. Taken together, our results suggest a critical role for the VAV interaction-dependent, extranuclear action of EZH2 in neoplastic transformation.
Asunto(s)
Transformación Celular Neoplásica/genética , Proteína Potenciadora del Homólogo Zeste 2/metabolismo , Regulación Neoplásica de la Expresión Génica , Neoplasias/patología , Proteínas Proto-Oncogénicas c-vav/metabolismo , Animales , Adhesión Celular/genética , Línea Celular Tumoral , Transformación Celular Neoplásica/patología , Citoplasma/genética , Citoplasma/patología , Proteína Potenciadora del Homólogo Zeste 2/genética , Proteína Potenciadora del Homólogo Zeste 2/aislamiento & purificación , Femenino , Técnicas de Silenciamiento del Gen , Células HEK293 , Humanos , Janus Quinasa 2/genética , Janus Quinasa 2/metabolismo , Células Jurkat , Metilación , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos NOD , Ratones SCID , Mutagénesis Sitio-Dirigida , Neoplasias/genética , Señales de Localización Nuclear/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Factor de Transcripción STAT3/genética , Factor de Transcripción STAT3/metabolismo , Talina/genética , Talina/metabolismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
BACKGROUND: The aim of this study was the ex vivo expansion of Umbilical Cord Blood hematopoietic stem cells on biocompatible nanofiber scaffolds. MATERIALS AND METHODS: CD133+ hematopoietic stem cells were separated from umbilical cord blood using MidiMacs (positive selection) system by means of monocolonal antibody CD133 (microbeads); subsequently, flowcytometry method was done to assess the purity of separated cells. Isolated cells were cultured on plate (2 Dimensional) and fibronectin conjugated polyethersulfon nanofiber scaffold, simultaneously (3 Dimensional). Colony assay test was performed to show colonization ability of expanded cells. RESULTS: Cell count analysis revealed that expansion of hematopoietic stem cells in 2dimensional (2D) environment was greater than 3dimensional (3D) condition (p= 0.01). Assessment of stem cell- phenotype after expansions was performed by flowcytometric analysis which is showed that the maintenance of CD133 marker in expanded cells in 3 dimensional condition were higher than expanded cells in 2 dimensional condition (p=0.01). Moreover, colony assay test was performed before and after of expansion to show colonization ability of expanded cells both in 3D and 2D culture and results revealed more ability of 3D culture compared with 2D culture (p= 0.03). CONCLUSION: The results of current study confirmed that umbilical cord blood CD133+ haematopoietic stem cells are able to expand on fibronectin conjugated polyethersulfon scaffold. These findings indicated that 3D is a proper and valuable cell culture system for hematopoietic stem cells expansion, compared to 2D in invitro situation.
RESUMEN
Insulin injection is the main way to combat against insulin-dependent diabetes mellitus effects. Today in some laboratories in the world, the investigators are trying to find some treatments for this disease with insulin-secreting pancreatic islet cells transplantation. Donor tissue in each step of work was prepared from 36 adult male wistar Rats weighted 250-300 grams (75-90 days). Transplantation was done in rats after 2-4 weeks induction of diabetes with 60mg/kg of streptozotocin injection by intravenous method. Encapsulation of pancreatic islet cells allows for transplantation in the absence of immunosuppression. This technique that is called "immunoisolation" is based on the principle that transplanted tissue is protected for the host immune system by an artificial or natural membrane. In this study, the levels of insulin, C-peptide and glucose in diabetic rats have been reached to normal range as compared to un-diabetic rats in 20 days after transplantation of islet cells, so that testis is immunoisolated place for islet cells transplantation. Inside the testis subcutaneously and intrapretoneally implantation of pure islet cells graft, that is a natural immunoisolation method, rapidly and permanently normalized the diabetic state of streptozocin-administered animals.
