RESUMEN
UNLABELLED: Ovarian cancer is an extremely aggressive disease associated with a high percentage of tumor recurrence and chemotherapy resistance. Understanding the underlying mechanism of tumor relapse is crucial for effective therapy of ovarian cancer. DNA damage-binding protein 2 (DDB2) is a DNA repair factor mainly involved in nucleotide excision repair. Here, a novel role was identified for DDB2 in the tumorigenesis of ovarian cancer cells and the prognosis of patients with ovarian cancer. Overexpressing DDB2 in human ovarian cancer cells suppressed its capability to recapitulate tumors in athymic nude mice. Mechanistic investigation demonstrated that DDB2 is able to reduce the cancer stem cell (CSC) population characterized with high aldehyde dehydrogenase activity in ovarian cancer cells, probably through disrupting the self-renewal capacity of CSCs. Low DDB2 expression correlates with poor outcomes among patients with ovarian cancer, as revealed from the analysis of publicly available gene expression array datasets. Given the finding that DDB2 protein expression is low in ovarian tumor cells, enhancement of DDB2 expression is a promising strategy to eradicate CSCs and would help to halt ovarian cancer relapse. IMPLICATIONS: DDB2 status has prognostic potential, and elevating its expression eradicates CSCs and could reduce ovarian cancer relapse.
Asunto(s)
Proteínas de Unión al ADN/biosíntesis , Células Madre Neoplásicas/patología , Neoplasias Ováricas/patología , Animales , Carcinogénesis/patología , Línea Celular Tumoral , Proteínas de Unión al ADN/genética , Femenino , Xenoinjertos , Humanos , Inmunohistoquímica , Ratones , Ratones Endogámicos NOD , Ratones Desnudos , Ratones SCID , Neoplasias Ováricas/genética , Neoplasias Ováricas/metabolismo , Análisis de Matrices Tisulares , TransfecciónRESUMEN
UNLABELLED: Elevated expression of the antiapoptotic factor Bcl-2 is believed to be one of the contributing factors to an increased relapse rate associated with multiple cisplatin-resistant cancers. DNA damage-binding protein complex subunit 2 (DDB2) has recently been revealed to play an important role in sensitizing human ovarian cancer cells to cisplatin-induced apoptosis through the downregulation of Bcl-2, but the underlying molecular mechanism remains poorly defined. Here, it is report that DDB2 functions as a transcriptional repressor for Bcl-2 in combination with DDB1. Quantitative ChIP and EMSA analysis revealed that DDB2 binds to a specific cis-acting element at the 5'-end of Bcl-2 P1 promoter. Overexpression of DDB2 resulted in marked losses of histone H3K9,14 acetylation along the Bcl-2 promoter and enhancer regions, concomitant with a local enrichment of HDAC1 to the Bcl-2 P1 core promoter in ovarian cancer cells. Coimmunoprecipitation and in vitro binding analyses identified a physical interaction between DDB1 and HDAC1, whereas downregulation of HDAC1 significantly enhanced Bcl-2 promoter activity. Finally, in comparison with wild-type DDB2, mutated DDB2, which is unable to repress Bcl-2 transcription, mediates a compromised apoptosis upon cisplatin treatment. Taken together, these data support a model wherein DDB1 and DDB2 cooperate to repress Bcl-2 transcription. DDB2 recognizes and binds to the Bcl-2 P1 promoter, and HDAC1 is recruited through the DDB1 subunit associated with DDB2 to deacetylate histone H3K9,14 across Bcl-2 regulatory regions, resulting in suppressed Bcl-2 transcription. IMPLICATIONS: Increasing the expression of DDB complex may provide a molecular strategy for cancer therapy.
Asunto(s)
Daño del ADN , Proteínas de Unión al ADN/metabolismo , Histona Desacetilasa 1/metabolismo , Neoplasias Ováricas/genética , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Apoptosis/fisiología , Línea Celular Tumoral , Proteínas de Unión al ADN/genética , Regulación hacia Abajo , Femenino , Células HEK293 , Histona Desacetilasa 1/genética , Histonas/genética , Histonas/metabolismo , Humanos , Neoplasias Ováricas/metabolismo , Regiones Promotoras Genéticas , Proteínas Proto-Oncogénicas c-bcl-2/genética , TransfecciónRESUMEN
IL-15 may have a role in the development of T cell large granular lymphocyte (T-LGL) or NKT leukemias. However, the mechanisms of action and the identity of the cell subset that undergoes leukemic transformation remain elusive. Here we show that in both mice and humans, NKp46 expression marks a minute population of WT NKT cells with higher activity and potency to become leukemic. Virtually 100% of T-LGL leukemias in IL-15 transgenic mice expressed NKp46, as did a majority of human T-LGL leukemias. The minute NKp46+ NKT population, but not the NKp46â» NKT population, was selectively expanded by overexpression of endogenous IL-15. Importantly, IL-15 transgenic NKp46â» NKT cells did not become NKp46+ in vivo, suggesting that NKp46+ T-LGL leukemia cells were the malignant counterpart of the minute WT NKp46+ NKT population. Mechanistically, NKp46+ NKT cells possessed higher responsiveness to IL-15 in vitro and in vivo compared with that of their NKp46â» NKT counterparts. Furthermore, interruption of IL-15 signaling using a neutralizing antibody could prevent LGL leukemia in IL-15 transgenic mice. Collectively, our data demonstrate that NKp46 identifies a functionally distinct NKT subset in mice and humans that appears to be directly susceptible to leukemic transformation when IL-15 is overexpressed. Thus, IL-15 signaling and NKp46 may be useful targets in the treatment of patients with T-LGL or NKT leukemia.
Asunto(s)
Antígenos Ly/metabolismo , Transformación Celular Neoplásica/inmunología , Leucemia Linfocítica Granular Grande/etiología , Receptor 1 Gatillante de la Citotoxidad Natural/metabolismo , Células T Asesinas Naturales/inmunología , Subgrupos de Linfocitos T/inmunología , Animales , Anticuerpos Monoclonales/administración & dosificación , Antígenos Ly/genética , Transformación Celular Neoplásica/genética , Humanos , Interleucina-15/genética , Interleucina-15/metabolismo , Subunidad beta del Receptor de Interleucina-2/antagonistas & inhibidores , Leucemia Linfocítica Granular Grande/genética , Leucemia Linfocítica Granular Grande/inmunología , Leucemia Linfocítica Granular Grande/terapia , Activación de Linfocitos , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Receptor 1 Gatillante de la Citotoxidad Natural/genética , Células T Asesinas Naturales/clasificación , Transducción de Señal/inmunología , Subgrupos de Linfocitos T/clasificaciónRESUMEN
The X-linked Foxp3 is a member of the forkhead/winged helix transcription factor family. Germline mutations cause lethal autoimmune diseases in males. Serendipitously, we observed that female mice heterozygous for the "scurfin" mutation of the Foxp3 gene (Foxp3(sf/+)) developed cancer at a high rate. The majority of the cancers were mammary carcinomas in which the wild-type Foxp3 allele was inactivated and HER-2/ErbB2 was overexpressed. Foxp3 bound and repressed the HER-2/ErbB2 promoter. Deletion, functionally significant somatic mutations, and downregulation of the FOXP3 gene were commonly found in human breast cancer samples and correlated significantly with HER-2/ErbB2 overexpression, regardless of the status of HER-2 amplification. Our data demonstrate that FOXP3 is an X-linked breast cancer suppressor gene and an important regulator of the HER-2/ErbB2 oncogene.
Asunto(s)
Neoplasias de la Mama/genética , Carcinoma/genética , Factores de Transcripción Forkhead/genética , Genes Supresores de Tumor/fisiología , Genes Ligados a X/genética , Genes erbB-2/genética , Animales , Neoplasias de la Mama/metabolismo , Carcinoma/metabolismo , Línea Celular Tumoral , Cromosomas Humanos X/genética , Regulación hacia Abajo/genética , Femenino , Regulación Neoplásica de la Expresión Génica/genética , Humanos , Neoplasias Mamarias Experimentales/genética , Neoplasias Mamarias Experimentales/metabolismo , Ratones , Ratones Endogámicos BALB C , Ratones Mutantes , Mutación/genética , Regiones Promotoras Genéticas/genética , Receptor ErbB-2/genética , Receptor ErbB-2/metabolismo , Proteínas Supresoras de Tumor/genética , Inactivación del Cromosoma X/genéticaRESUMEN
Cancer stem cells (CSCs) have been identified in hematopoietic and solid tumors. However, their precursors-namely, precancerous stem cells (pCSCs) -have not been characterized. Here we experimentally define the pCSCs that have the potential for both benign and malignant differentiation, depending on environmental cues. While clonal pCSCs can develop into various types of tissue cells in immunocompetent mice without developing into cancer, they often develop, however, into leukemic or solid cancers composed of various types of cancer cells in immunodeficient mice. The progress of the pCSCs to cancers is associated with the up-regulation of c-kit and Sca-1, as well as with lineage markers. Mechanistically, the pCSCs are regulated by the PIWI/AGO family gene called piwil2. Our results provide clear evidence that a single clone of pCSCs has the potential for both benign and malignant differentiation, depending on the environmental cues. We anticipate pCSCs to be a novel target for the early detection, prevention, and therapy of cancers.
Asunto(s)
Diferenciación Celular/fisiología , Transformación Celular Neoplásica/patología , Células Madre/citología , Células Madre/patología , Animales , Blastocisto/patología , Diferenciación Celular/efectos de la radiación , División Celular , Células Cultivadas , Señales (Psicología) , Ambiente , Síndromes de Inmunodeficiencia/complicaciones , Síndromes de Inmunodeficiencia/patología , Hígado/patología , Ratones , Fenotipo , Lesiones Precancerosas/patología , ARN Interferente Pequeño/genética , Bazo/patologíaRESUMEN
Multiple sclerosis (MS) is a chronic neurological disease of unknown etiology, but a genetic basis for the disease is undisputed. We have reported that CD24 is required for the pathogenicity of autoreactive T cells in experimental autoimmune encephalomyelitis, the mouse model of MS. Here we investigate the contribution of CD24 to MS by studying single-nucleotide polymorphism in the ORF among 242 MS patients and 207 population controls. This single-nucleotide polymorphism results in replacement of alanine (CD24a) with valine (CD24v) in the mature protein. We found that the CD24v/v renders a >2-fold increase in the relative risk of MS in the general population (P = 0.023). Among familial MS, the CD24v allele is preferentially transmitted into affected individuals (P = 0.017). Furthermore, 50% of CD24v/v patients with expanded disability status scale 6.0 reached the milestone in 5 years, whereas the CD24a/v (P = 0.00037) and CD24a/a (P = 0.0016) patients did so in 16 and 13 years, respectively. Moreover, our data suggest that the CD24v/v patients expressed higher levels of CD24 on peripheral blood T cells than did the CD24a/a patients. Transfection with CD24a and CD24v cDNA demonstrated that the CD24v allele can be expressed at higher efficiency than the CD24a alleles. Thus, CD24 polymorphism is a genetic modifier for susceptibility and progression of MS in the central Ohio cohort that we studied, perhaps by affecting the efficiency of CD24 expression on the cell surface.
Asunto(s)
Antígenos CD/genética , Antígenos CD/fisiología , Glicoproteínas de Membrana , Esclerosis Múltiple/diagnóstico , Esclerosis Múltiple/genética , Alanina/química , Alelos , Animales , Antígeno CD24 , Complejo CD3/biosíntesis , Membrana Celular/metabolismo , Clonación Molecular , ADN Complementario/metabolismo , Progresión de la Enfermedad , Relación Dosis-Respuesta a Droga , Encefalomielitis Autoinmune Experimental/genética , Citometría de Flujo , Predisposición Genética a la Enfermedad , Genotipo , Humanos , Ratones , Modelos Genéticos , Sistemas de Lectura Abierta , Linaje , Reacción en Cadena de la Polimerasa , Polimorfismo de Nucleótido Simple , Factores de Riesgo , Factores de Tiempo , Transfección , Valina/químicaRESUMEN
Optimal activation of T cells requires delivery of both antigenic and costimulatory signals. It is unclear, however, if the function of the natural killer (NK) cells is also modulated by these 2 signals. Here we report that efficient control of solid allogeneic tumors by NK cells depends on codelivery of both B7-1 and major histocompatibility complex (MHC) class I on the tumor cells. The codelivery is required for optimal expansion and effector function of NK cells in response to both melanoma and plasmocytoma that expressed allogeneic MHC class I. Our results demonstrate that the 2 signals required for T-cell function also can regulate NK immunity and reveal an important similarity between the innate NK response and the adaptive T-cell response.
Asunto(s)
Antígeno B7-1/inmunología , Antígenos H-2/inmunología , Células Asesinas Naturales/inmunología , Miembro 3 de la Subfamilia B de Transportadores de Casetes de Unión a ATP , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/inmunología , Animales , Antígenos Ly/análisis , Antígeno B7-1/genética , Ciclo Celular , Línea Celular Tumoral/inmunología , Citotoxicidad Inmunológica , Antígenos H-2/genética , Antígeno de Histocompatibilidad H-2D , Células Asesinas Naturales/clasificación , Lectinas Tipo C , Activación de Linfocitos , Melanoma Experimental/inmunología , Melanoma Experimental/patología , Ratones , Ratones Endogámicos C57BL , Plasmacitoma/inmunología , Plasmacitoma/patología , Receptores Similares a Lectina de Células NK , Proteínas Recombinantes de Fusión/inmunología , Transducción de Señal/inmunología , TransfecciónRESUMEN
B7H1 (PDL1) and B7DC (PDL2) are two new members of the B7 family that can interact with PD-1, a putative negative regulator for immune function. Recent studies have provided evidence for inhibitory functions of both members via PD-1. Meanwhile, compelling evidence exists for costimulatory function of both members. Here we demonstrate that expression of B7DC on the tumor cells promotes CD8 T cell-mediated rejection of tumor cells, at both the induction and effector phase of antitumor immunity. Moreover, B7DC binds to PD-1(-/-) cells and enhances T cell killing in a PD-1-independent mechanism. Our results demonstrate a novel pathway for B7DC to promote tumor immunity and may reconcile the apparently contradictory findings on the function of B7DC.
Asunto(s)
Antígenos de Superficie , Antígeno B7-1/inmunología , Proteínas Sanguíneas , Linfocitos T CD8-positivos/inmunología , Neoplasias Experimentales/inmunología , Péptidos , Proteínas/inmunología , Traslado Adoptivo , Animales , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/inmunología , Proteínas Reguladoras de la Apoptosis , Antígeno B7-1/genética , Antígeno B7-1/metabolismo , Antígeno B7-H1 , Linfocitos T CD8-positivos/metabolismo , Células CHO , Cricetinae , Citotoxicidad Inmunológica , Glicoproteínas de Membrana , Ratones , Ratones Endogámicos BALB C , Ratones Transgénicos , Trasplante de Neoplasias , Proteína 2 Ligando de Muerte Celular Programada 1 , Receptor de Muerte Celular Programada 1 , Proteínas/metabolismo , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/metabolismo , Bazo/citología , Bazo/inmunología , Linfocitos T Citotóxicos/inmunología , Transgenes , Quimera por Trasplante , Células Tumorales CultivadasRESUMEN
Dendritic cells (DC) are the professional APCs that initiate T cell immune responses. DC can develop from both myeloid and lymphoid progenitors. In the mouse, the CD8alpha(+) DC had been designated as "lymphoid" DC, and CD8alpha(-) DC as "myeloid" DC until recently when it was demonstrated that common myeloid progenitors can also give rise to CD8alpha(+) DC in bone marrow chimera mice. However, it is still not clear which committed myeloid lineages differentiate into CD8alpha(+) DC. Because monocytes can differentiate into DC in vivo, the simplest hypothesis is that the CD8alpha(+) DC can be derived from the monocyte/macrophage. In this study we show that cell clones, isolated from CD8alpha(+) DC lymphoma but with a monocytic phenotype (CD11c(low/-)D11b(high)CD8alpha(-)I-A(low)), can redifferentiate into CD8alpha(+) DC either when stimulated by LPS and CD40L or when they migrate into the lymphoid organs. Maturation of DC in vivo correlated with strong priming of allogeneic T cells. Moreover, the monocytes from cultured splenocytes or peritoneal exudates macrophages of wild-type mice are also capable of differentiating into CD11c(+)CD8alpha(+) DC after their migration into the draining lymph nodes. Our results suggest that monocytes can be direct precursors for CD11c(+)CD8alpha(+) DC in vivo. In addition, the monocyte clones described in this study may be valuable for studying the differentiation and function of CD8alpha(+) DC that mediate cross-presentation of Ag to CD8 T cells specific for cell-associate Ags.
Asunto(s)
Antígenos CD8/biosíntesis , Células Dendríticas/citología , Células Dendríticas/inmunología , Monocitos/citología , Monocitos/inmunología , Células Madre/citología , Células Madre/inmunología , Células 3T3 , Traslado Adoptivo , Animales , Diferenciación Celular/genética , Diferenciación Celular/inmunología , Separación Celular , Células Clonales , Proteínas de Unión al ADN/deficiencia , Proteínas de Unión al ADN/genética , Células Dendríticas/metabolismo , Células Dendríticas/patología , Antígenos H-2/inmunología , Antígeno de Histocompatibilidad H-2D , Inmunización , Inyecciones Subcutáneas , Ganglios Linfáticos/inmunología , Ganglios Linfáticos/patología , Linfoma/genética , Linfoma/inmunología , Linfoma/patología , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Monocitos/metabolismo , Monocitos/trasplante , Trasplante de Neoplasias , Factor de Transcripción STAT1 , Células Madre/metabolismo , Transactivadores/deficiencia , Transactivadores/genética , Células Tumorales Cultivadas , Proteína p53 Supresora de Tumor/deficiencia , Proteína p53 Supresora de Tumor/genéticaRESUMEN
Expression of cell surface MHC class I:peptide complex requires coordinated expression of multiple genes such as MHC class I heavy chain, beta(2)-microglobulin (beta(2)m), transporters associated with antigen-processing (TAP)-1 and TAP-2, and proteosomal components low-molecular weight polypeptide (LMP)-2 and LMP-7. All of these genes are expressed at defined and distinct levels in normal tissues, and are inducible by IFN-gamma. While the cis elements involved in transcription of the MHC class I heavy chain, beta(2)m, TAP-1 and LMP-2 have been analyzed extensively, those for TAP-2 and LMP-7 have not been well studied. Here we systematically analyzed the cis elements for TAP-2 transcription. We found at least two independent elements that are sufficient to activate transcription of a reporter gene. One (hereby called TAP-2 P1) is located 5' to the TAP-2 exon 1, while the other (hereby called TAP-2 P2) is a transcription initiator residing in intron 1. Analysis of the 5' sequence of TAP-2 mRNA indicates that both promoters are active. Moreover, while the TAP-2 promoter region contains cis elements that can mediate TAP-2 induction by IFN-gamma, such as gamma-activation site and IFN response factor binding element (IRFE), only the IRFE is required for IFN-gamma induction of TAP-2 promoter in vitro. The IRFE appears to work as an enhancer for the initiator (P2). Together with another promoter recently identified by others, TAP-2 therefore has three independent promoters that can be differentially regulated.