RESUMO
The presence of hypoxic regions in solid tumors is an adverse prognostic factor for patient outcome. Here, we show that hypoxia induces the expression of Ephrin-A3 through a novel hypoxia-inducible factor (HIF)-mediated mechanism. In response to hypoxia, the coding EFNA3 mRNA levels remained relatively stable, but HIFs drove the expression of previously unknown long noncoding (lnc) RNAs from EFNA3 locus and these lncRNA caused Ephrin-A3 protein accumulation. Ephrins are cell surface proteins that regulate diverse biological processes by modulating cellular adhesion and repulsion. Mounting evidence implicates deregulated ephrin function in multiple aspects of tumor biology. We demonstrate that sustained expression of both Ephrin-A3 and novel EFNA3 lncRNAs increased the metastatic potential of human breast cancer cells, possibly by increasing the ability of tumor cells to extravasate from the blood vessels into surrounding tissue. In agreement, we found a strong correlation between high EFNA3 expression and shorter metastasis-free survival in breast cancer patients. Taken together, our results suggest that hypoxia could contribute to metastatic spread of breast cancer via HIF-mediated induction of EFNA3 lncRNAs and subsequent Ephrin-A3 protein accumulation.
Assuntos
Neoplasias da Mama/metabolismo , Loci Gênicos , Fator 1 Induzível por Hipóxia/metabolismo , Proteínas de Neoplasias/metabolismo , RNA Longo não Codificante/biossíntese , RNA Neoplásico/biossíntese , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Hipóxia Celular/genética , Linhagem Celular Tumoral , Efrina-A3/genética , Efrina-A3/metabolismo , Feminino , Células Endoteliais da Veia Umbilical Humana , Humanos , Fator 1 Induzível por Hipóxia/genética , Camundongos , Camundongos Nus , Metástase Neoplásica , Proteínas de Neoplasias/genética , RNA Longo não Codificante/genética , RNA Neoplásico/genética , Peixe-ZebraRESUMO
The Slit family of secreted proteins acts through the Roundabout (Robo) receptors to repel axonal migration during central nervous system development. Emerging evidence shows that Slit/Robo interactions also play a role in angiogenesis. The effect of Robo signaling on endothelial cells has been shown to be context-dependent. However, the role of Slit/Robo in pericytes has been largely unexplored. The aim of this study was to determine the effect of Slit2 on primary human pericytes and to address the underlying mechanisms, including the receptors potentially implicated. We demonstrate that both Robo1 and Robo4 are expressed by human pericytes. In the presence of their ligand Slit2, spontaneous and PDGF-induced migration of pericytes was impaired. This antimigratory activity of Slit-2 correlated with the inhibition of actin-based protrusive structures. Interestingly, human pericyte interaction with immobilized Slit2 was inhibited in the presence of anti-Robo1 and anti-Robo4 blocking antibodies, suggesting the implication of both receptors. These results add new insights into the role of Slit proteins during the angiogenic process that relies on the directional migration not only of endothelial cells but also of pericytes.
Assuntos
Axônios/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Neovascularização Fisiológica/efeitos dos fármacos , Proteínas do Tecido Nervoso/farmacologia , Pericitos/efeitos dos fármacos , Axônios/metabolismo , Axônios/fisiologia , Encéfalo/irrigação sanguínea , Encéfalo/citologia , Movimento Celular/genética , Células Cultivadas , Regulação da Expressão Gênica , Células HEK293 , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Células Endoteliais da Veia Umbilical Humana/fisiologia , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Família Multigênica/genética , Neovascularização Fisiológica/genética , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Pericitos/metabolismo , Pericitos/fisiologia , Ligação Proteica/efeitos dos fármacos , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Proteínas RoundaboutRESUMO
As an alternative to recombinant protein administration, ex vivo gene-modified cells may provide a novel strategy for systemic delivery of therapeutic proteins. This approach has been used in preclinical and clinical studies of a plethora of pathological conditions, including anemia, hemophilia and cancer for the production of erythropoietin, coagulation factors, immunostimulatory cytokines, recombinant antibodies and angiogenesis inhibitors. Cell delivery vehicles may also be varied: autologous or allogeneic, precursor or terminally differentiated cells, with targeting properties or immobilized in immunoprotective devices. This field did not meet the expectation raised initially, mainly because of difficulties with obtaining therapeutic plasma levels and the short lifespan of producer cells that hampered clinical application. Different non-hematopoietic stem/progenitor cells have emerged as potential delivery vehicles, since they are easy to obtain, expand and transduce, and they exhibit prolonged lifespans (with mesenchymal stem cells probably being the most popular cell type, but not the only one). Special emphasis is placed on the different routes used to deliver these cellular vehicles and the controversies about their targeting abilities.
