RESUMO
BRD4 assembles transcriptional machinery at gene super-enhancer regions and governs the expression of genes that are critical for cancer progression. However, it remains unclear whether BRD4-mediated gene transcription is required for tumor cells to develop drug resistance. Our data show that prolonged treatment of luminal breast cancer cells with AKT inhibitors induces FOXO3a dephosphorylation, nuclear translocation, and disrupts its association with SirT6, eventually leading to FOXO3a acetylation as well as BRD4 recognition. Acetylated FOXO3a recognizes the BD2 domain of BRD4, recruits the BRD4/RNAPII complex to the CDK6 gene promoter, and induces its transcription. Pharmacological inhibition of either BRD4/FOXO3a association or CDK6 significantly overcomes the resistance of luminal breast cancer cells to AKT inhibitors in vitro and in vivo. Our study reports the involvement of BRD4/FOXO3a/CDK6 axis in AKTi resistance and provides potential therapeutic strategies for treating resistant breast cancer.
Assuntos
Neoplasias da Mama/metabolismo , Quinase 6 Dependente de Ciclina/metabolismo , Proteína Forkhead Box O3/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fatores de Transcrição/metabolismo , Acetilação/efeitos dos fármacos , Animais , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Proteínas de Ciclo Celular , Linhagem Celular Tumoral , Núcleo Celular/genética , Núcleo Celular/metabolismo , Quinase 6 Dependente de Ciclina/genética , Feminino , Proteína Forkhead Box O3/genética , Regulação da Expressão Gênica , Compostos Heterocíclicos com 3 Anéis/administração & dosagem , Humanos , Camundongos , Camundongos Nus , Proteínas Nucleares/química , Proteínas Nucleares/genética , Oxidiazóis/administração & dosagem , Regiões Promotoras Genéticas , Ligação Proteica/efeitos dos fármacos , Domínios Proteicos , Inibidores de Proteínas Quinases/administração & dosagem , Transporte Proteico/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/genética , Pirimidinas/administração & dosagem , Pirróis/administração & dosagem , Sirtuínas/genética , Sirtuínas/metabolismo , Fatores de Transcrição/química , Fatores de Transcrição/genéticaRESUMO
Twist is a key transcription factor for Epithelial-mesenchymal transition (EMT), which is a cellular de-differentiation program that promotes invasion and metastasis, confers tumor cells with cancer stem cell (CSC)-like characteristics, and increases therapeutic resistance. However, the mechanisms that facilitate the functions of Twist remain unclear. Here we report that Twist overexpression increased expression of PAR1, an upstream regulator of the Hippo pathway; PAR1 promotes invasion, migration, and CSC-like properties in breast cancer by activating the transcriptional co-activator TAZ. Our study indicates that Hippo pathway inhibition is required for the increased migratory and invasiveness ability of breast cancer cells in Twist-mediated EMT.
Assuntos
Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Transição Epitelial-Mesenquimal , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais , Apoptose/genética , Neoplasias da Mama/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Sobrevivência Celular/genética , Transição Epitelial-Mesenquimal/genética , Feminino , Expressão Gênica , Técnicas de Silenciamento de Genes , Via de Sinalização Hippo , Humanos , Invasividade Neoplásica , Fatores de Transcrição da Família Snail/genética , Fatores de Transcrição da Família Snail/metabolismo , Fatores de Transcrição Twist/genética , Fatores de Transcrição Twist/metabolismoRESUMO
Inflammation is a beneficial response that can remove pathogens, repair injured tissue and restore homeostasis to damaged tissues and organs. However, increasing evidence indicate that chronic inflammation plays a pivotal role in tumor development, as well as progression, metastasis, and resistance to chemotherapy. We will review the current knowledge regarding the contribution of inflammation to epithelial mesenchymal transition. We will also provide some perspectives on the relationship between ER-stress signals and metabolism, and the role of these processes in the development of inflammation.
Assuntos
Inflamação/complicações , Inflamação/patologia , Metástase Neoplásica/patologia , Neoplasias/etiologia , Neoplasias/patologia , Animais , Transformação Celular Neoplásica , Progressão da Doença , Transição Epitelial-Mesenquimal , Humanos , Hipóxia/patologiaRESUMO
Cancer-secreted microRNAs (miRNAs) are emerging mediators of cancer-host crosstalk. Here we show that miR-105, which is characteristically expressed and secreted by metastatic breast cancer cells, is a potent regulator of migration through targeting the tight junction protein ZO-1. In endothelial monolayers, exosome-mediated transfer of cancer-secreted miR-105 efficiently destroys tight junctions and the integrity of these natural barriers against metastasis. Overexpression of miR-105 in nonmetastatic cancer cells induces metastasis and vascular permeability in distant organs, whereas inhibition of miR-105 in highly metastatic tumors alleviates these effects. miR-105 can be detected in the circulation at the premetastatic stage, and its levels in the blood and tumor are associated with ZO-1 expression and metastatic progression in early-stage breast cancer.
Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Endotélio Vascular/patologia , MicroRNAs/metabolismo , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/metabolismo , Processos de Crescimento Celular/fisiologia , Linhagem Celular Tumoral , Movimento Celular , Endotélio Vascular/metabolismo , Feminino , Humanos , MicroRNAs/genética , Metástase NeoplásicaRESUMO
Vascularization is an important factor that affects diabetic wound healing. There is increasing evidence that myeloid cell lineages play a role in neovascularization. In this study, the efficiency of Gr-1+CD11b+ myeloid cells to home to the site of injury and enhance diabetic wound healing by neoangiogenesis after intravenous administration was investigated. Gr-1+CD11b+ myeloid cells were injected into tail vein after establishment of dorsal window chamber, hindlimb ischaemia and ear-punch injury in diabetic or non-diabetic mice. The Gr-1+CD11b+ myeloid cells efficiently homed to the site of injury after intravenous administration and increased neoangiogenesis. The chemokine receptor type 4 (CXCR4) is robustly expressed by Gr-1+CD11b+ myeloid cells. Inhibition of CXCR4 decreases the homing ability of Gr-1+CD11b+ myeloid cells to the site of injury, which indicates that the CXCR4/SDF-1 axis plays an important role in the homing of Gr-1+CD11b+ myeloid cells to the site of injury. In addition, Gr-1+CD11b+ myeloid cells were found to improve blood flow recovery of ischaemic limb and enhance wound healing in diabetic mice by neoangiogenesis after intravenous administration. Taken together, the results of this study suggest that Gr-1+CD11b+ myeloid cells may serve as a potential cell therapy for diabetic wound healing.
Assuntos
Antígeno CD11b/metabolismo , Diabetes Mellitus Experimental/fisiopatologia , Orelha/irrigação sanguínea , Extremidade Inferior/irrigação sanguínea , Células Mieloides/imunologia , Neovascularização Fisiológica , Receptores de Quimiocinas/metabolismo , Cicatrização , Administração Intravenosa , Animais , Western Blotting , Células Cultivadas , Diabetes Mellitus Experimental/metabolismo , Orelha/lesões , Orelha/patologia , Citometria de Fluxo , Técnicas Imunoenzimáticas , Isquemia/imunologia , Isquemia/metabolismo , Isquemia/patologia , Extremidade Inferior/patologia , Camundongos , Camundongos Endogâmicos C57BL , Células Mieloides/citologia , Células Mieloides/metabolismo , Transdução de SinaisRESUMO
Communication between endothelial cells (ECs) and mural cells is critical in vascular maturation. Genetic studies suggest that angiopoietin/Tie2 signaling may play a role in the recruitment of pericytes or smooth muscle cells (SMCs) during vascular maturation. However, the molecular mechanism is unclear. We used microarray technology to analyze genes regulated by angiopoietin-1 (Ang1), an agonist ligand for Tie2, in endothelial cells (ECs). We observed that hepatocyte growth factor (HGF), a mediator of mural cell motility, was up-regulated by Ang1 stimulation. We confirmed this finding by Northern blot and Western blot analyses in cultured vascular endothelial cells. Furthermore, stimulation of ECs with Ang1 increased SMC migration toward endothelial cells in a coculture assay. Addition of a neutralizing anti-HGF antibody inhibited Ang1-induced SMC recruitment, indicating that the induction of SMC migration by Ang1 was caused by the increase of HGF. Interestingly, Ang2, an antagonist ligand of Tie2, inhibited Ang1-induced HGF production and Ang1-induced SMC migration. Finally, we showed that deletion of Tie2 in transgenic mouse reduced HGF production. Collectively, our data reveal a novel mechanism of Ang/Tie2 signaling in regulating vascular maturation and suggest that a delicate balance between Ang1 and Ang2 is critical in this process.
Assuntos
Angiopoietina-1/metabolismo , Angiopoietina-2/metabolismo , Movimento Celular/fisiologia , Fator de Crescimento de Hepatócito/biossíntese , Miócitos de Músculo Liso/fisiologia , Transdução de Sinais/fisiologia , Angiopoietina-1/farmacologia , Angiopoietina-2/farmacologia , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/fisiologia , Movimento Celular/efeitos dos fármacos , Células Cultivadas , Células Endoteliais/citologia , Células Endoteliais/fisiologia , Perfilação da Expressão Gênica , Humanos , Miócitos de Músculo Liso/citologia , Análise de Sequência com Séries de Oligonucleotídeos , Pericitos/citologia , Pericitos/fisiologia , Receptor TIE-2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/fisiologiaRESUMO
Tie2 and VEGF receptors (VEGFRs) are tyrosine kinases that play essential roles in angiogenesis. Activation of both receptors leads to the activation of Akt, an important mediator of cell survival and cell motility. In this study, we compared the role of Akt in Tie2-mediated versus VEGF-mediated endothelial cell (EC) survival and EC sprouting. Our data show that Akt is required and sufficient to mediate Ang1-induced EC survival in response to growth factor depletion. Blocking Akt function abolishes angiopoietin 1 (Ang1), a ligand for Tie2, mediated EC survival, and activating Akt rescues a Tie2 blockade-induced EC apoptosis. In contrast, activating Akt rescues EC apoptosis induced by a VEGF blockade, but interestingly, blocking Akt function has no effects on VEGF-induced EC survival, demonstrating that Akt is sufficient but not required for VEGF-mediated EC survival. In addition, we show that both Ang1 and VEGF induce EC sprouting in a three-dimensional collagen gel, which depends on the activation of Akt. Blocking Akt action inhibited EC sprouting induced by Ang1 or VEGF. Therefore, the data show that Akt is the primary mediator of Ang1-induced EC survival while multiple pathways are involved downstream of VEGF responsible for EC survival. However, Akt is required and sufficient to mediate the EC sprouting induced by both Ang1 and VEGF.
Assuntos
Angiopoietina-1/metabolismo , Vasos Sanguíneos/crescimento & desenvolvimento , Endotélio Vascular/crescimento & desenvolvimento , Neovascularização Fisiológica/fisiologia , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Receptor TIE-2/metabolismo , Angiopoietina-1/genética , Apoptose/fisiologia , Vasos Sanguíneos/citologia , Vasos Sanguíneos/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Células Cultivadas , Colágeno/farmacologia , Endotélio Vascular/citologia , Endotélio Vascular/efeitos dos fármacos , Géis/farmacologia , Vetores Genéticos/genética , Humanos , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Neovascularização Patológica/fisiopatologia , Neovascularização Fisiológica/efeitos dos fármacos , Neovascularização Fisiológica/genética , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Proto-Oncogênicas/agonistas , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt , Receptor TIE-2/genética , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Transfecção , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismoAssuntos
Diagnóstico por Imagem/métodos , Microscopia/métodos , Modelos Animais , Neovascularização Patológica/patologia , Animais , Artrite/patologia , Velocidade do Fluxo Sanguíneo/fisiologia , Vasos Sanguíneos/patologia , Vasos Sanguíneos/fisiopatologia , Permeabilidade Capilar/fisiologia , Linhagem Celular Tumoral , Neovascularização da Córnea/patologia , Dilatação Patológica/patologia , Eritrócitos/química , Feminino , Corantes Fluorescentes/análise , Proteínas de Fluorescência Verde , Hipóxia/fisiopatologia , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Neoplasias Mamárias Experimentais/patologia , Neoplasias Mamárias Experimentais/fisiopatologia , Camundongos , Camundongos Transgênicos , Microscopia Confocal , Microscopia de Fluorescência por Excitação Multifotônica , Neoplasias/irrigação sanguínea , Neoplasias/patologia , Neoplasias/terapia , Neovascularização Patológica/fisiopatologia , Ratos , Receptor de TIE-1/genética , Receptor de TIE-1/metabolismo , Receptor TIE-2/genética , Receptor TIE-2/metabolismo , Receptores de Fatores de Crescimento do Endotélio Vascular/genética , Receptores de Fatores de Crescimento do Endotélio Vascular/metabolismoRESUMO
The vascular wall is mainly composed of endothelial cells (ECs) and smooth muscle cells (SMCs). The crosstalking between these two cell types is critical in the vascular maturation process. Genetic studies suggest that the Tie2/angiopoietin 1 (Ang1) pathway regulates vascular remodeling. However, the molecular mechanism is unclear. PDGF is a potent chemoattractant for SMCs, and TGF-beta regulates SMC differentiation. Here, we examined gene regulation. PDGF-B stimulation upregulated Ang1 expression in SMCs through the PI3K and PKC pathways. PDGF-B stimulation also produced an acute induction of TGF-beta expression in SMCs through the MAPK/ERK pathway. Interestingly, TGF-beta negatively regulated Ang1 expression induced by the PDGF-B stimulation in SMCs. Reciprocally, we observed that stimulation of ECs with either Ang1 or TGF-beta slightly downregulated PDGF expression. A combination of both TGF-beta with Ang1 produced much stronger downregulation of PDGF. Our data showed complex gene regulations that include both positive and negative regulations between ECs and SMCs to maintain vascular homeostasis.