RESUMO
NKX2 homeobox family proteins have a role in cancer development. Here we show that NKX2-3 is overexpressed in tumour cells from a subset of patients with marginal-zone lymphomas, but not with other B-cell malignancies. While Nkx2-3-deficient mice exhibit the absence of marginal-zone B cells, transgenic mice with expression of NKX2-3 in B cells show marginal-zone expansion that leads to the development of tumours, faithfully recapitulating the principal clinical and biological features of human marginal-zone lymphomas. NKX2-3 induces B-cell receptor signalling by phosphorylating Lyn/Syk kinases, which in turn activate multiple integrins (LFA-1, VLA-4), adhesion molecules (ICAM-1, MadCAM-1) and the chemokine receptor CXCR4. These molecules enhance migration, polarization and homing of B cells to splenic and extranodal tissues, eventually driving malignant transformation through triggering NF-κB and PI3K-AKT pathways. This study implicates oncogenic NKX2-3 in lymphomagenesis, and provides a valid experimental mouse model for studying the biology and therapy of human marginal-zone B-cell lymphomas.
Assuntos
Proteínas de Homeodomínio/genética , Linfócitos/metabolismo , Linfoma de Zona Marginal Tipo Células B/genética , Receptores de Antígenos de Linfócitos B/genética , Transdução de Sinais/genética , Fatores de Transcrição/genética , Animais , Moléculas de Adesão Celular/genética , Moléculas de Adesão Celular/metabolismo , Perfilação da Expressão Gênica , Proteínas de Homeodomínio/metabolismo , Humanos , Estimativa de Kaplan-Meier , Tecido Linfoide/metabolismo , Linfoma de Zona Marginal Tipo Células B/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosforilação , Receptores de Antígenos de Linfócitos B/metabolismo , Quinase Syk/genética , Quinase Syk/metabolismo , Fatores de Transcrição/metabolismoRESUMO
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Assuntos
Humanos , Cateterismo Urinário/enfermagem , Cateteres Urinários , Infecções Relacionadas a Cateter/prevenção & controle , Drenagem/enfermagem , Derivação Urinária/enfermagem , DesinfecçãoRESUMO
Glioblastoma multiforme (GBM)-initiating cells (GICs) represent a tumor subpopulation with neural stem cell-like properties that is responsible for the development, progression and therapeutic resistance of human GBM. We have recently shown that blockade of NFκB pathway promotes terminal differentiation and senescence of GICs both in vitro and in vivo, indicating that induction of differentiation may be a potential therapeutic strategy for GBM. MicroRNAs have been implicated in the pathogenesis of GBM, but a high-throughput analysis of their role in GIC differentiation has not been reported. We have established human GIC cell lines that can be efficiently differentiated into cells expressing astrocytic and neuronal lineage markers. Using this in vitro system, a microarray-based high-throughput analysis to determine global expression changes of microRNAs during differentiation of GICs was performed. A number of changes in the levels of microRNAs were detected in differentiating GICs, including over-expression of hsa-miR-21, hsa-miR-29a, hsa-miR-29b, hsa-miR-221 and hsa-miR-222, and down-regulation of hsa-miR-93 and hsa-miR-106a. Functional studies showed that miR-21 over-expression in GICs induced comparable cell differentiation features and targeted SPRY1 mRNA, which encodes for a negative regulator of neural stem-cell differentiation. In addition, miR-221 and miR-222 inhibition in differentiated cells restored the expression of stem cell markers while reducing differentiation markers. Finally, miR-29a and miR-29b targeted MCL1 mRNA in GICs and increased apoptosis. Our study uncovers the microRNA dynamic expression changes occurring during differentiation of GICs, and identifies miR-21 and miR-221/222 as key regulators of this process.
Assuntos
Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Diferenciação Celular/genética , Glioblastoma/genética , Glioblastoma/patologia , MicroRNAs/metabolismo , Células-Tronco Neoplásicas/metabolismo , Animais , Apoptose/genética , Astrócitos/metabolismo , Astrócitos/patologia , Biomarcadores Tumorais/metabolismo , Neoplasias Encefálicas/cirurgia , Linhagem Celular Tumoral , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Proteína Glial Fibrilar Ácida/metabolismo , Glioblastoma/cirurgia , Humanos , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , MicroRNAs/genética , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Células-Tronco Neoplásicas/patologia , Nestina/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Fosfoproteínas/metabolismo , Esferoides Celulares/metabolismo , Esferoides Celulares/patologia , Tubulina (Proteína)/metabolismoRESUMO
Glioblastoma (GBM) is associated with infiltration of peritumoral (PT) parenchyma by isolated tumor cells that leads to tumor regrowth. Recently, GBM stem-like or initiating cells (GICs) have been identified in the PT area, but whether these GICs have enhanced migratory and invasive capabilities compared with GICs from the tumor mass (TM) is presently unknown. We isolated GICs from the infiltrated PT tissue and the TM of three patients and found that PT cells have an advantage over TM cells in two-dimensional and three-dimensional migration and invasion assays. Interestingly, PT cells display a high plasticity in protrusion formation and cell shape and their migration is insensitive to substrate stiffness, which represent advantages to infiltrate microenvironments of different rigidity. Furthermore, mouse and chicken embryo xenografts revealed that only PT cells showed a dispersed distribution pattern, closely associated to blood vessels. Consistent with cellular plasticity, simultaneous Rac and RhoA activation are required for the enhanced invasive capacity of PT cells. Moreover, Rho GTPase signaling modulators αVß3 and p27 play key roles in GIC invasiveness. Of note, p27 is upregulated in TM cells and inhibits RhoA activity. Gene silencing of p27 increased the invasive capacity of TM GICs. Additionally, ß3 integrin is upregulated in PT cells. Blockade of dimeric integrin αVß3, a Rac activator, reduced the invasive capacity of PT GICs in vitro and abrogated the spreading of PT cells into chicken embryos. Thus, our results describe the invasive features acquired by a unique subpopulation of GICs that infiltrate neighboring tissue.
