RESUMEN
Recent studies on recovery of consciousness of subjects in a vegetative state (VS) admitted to rehabilitation units have focused mainly on the identification of prognostic factors, whereas few studies have focused on outcome. The aim of this study was to compare demographic and clinical data and report functional outcome of patients in a VS due to severe acquired brain injury (ABI) of different aetiologies. The study was a retrospective multicentre cohort study and involved 492 patients in a VS due to traumatic (TBI) or non-traumatic (NTBI) severe ABI admitted to 29 Italian rehabilitation units. Demographic and clinical data recorded included age, gender, aetiology, Glasgow Coma Scale score; onset-to-admission interval; length of stay in the rehabilitation unit; the department from which they were referred; and the presence of percutaneous endoscopic gastrostomy or tracheostomy. Recovery of consciousness and disability were evaluated using a discharge Disability Rating Scale. At discharge, 53.11% patients had emerged from VS, with TBI subjects significantly more likely to recover consciousness than NTBI ones. Subjects with NTBI had a significantly worse prognosis than those with TBI, and within the NTBI group, subjects with a cerebrovascular aetiology had a better outcome than those with an anoxic aetiology. Among the patients who emerged from VS, 71.30% of TBI and 83.06% of NTBI subjects presented extremely severe disability. Only 37.93% of subjects affected by TBI and 17.44% of those affected by NTBI who presented extremely severe disability returned home after their rehabilitation stay. Even though almost a half of the patients emerged from VS, a large number of these subjects showed severe disability, often making it impossible for them to return home. This situation has a major impact on the healthcare system.
Asunto(s)
Lesiones Encefálicas/complicaciones , Evaluación de Resultado en la Atención de Salud/estadística & datos numéricos , Estado Vegetativo Persistente/rehabilitación , Adulto , Lesiones Traumáticas del Encéfalo/complicaciones , Femenino , Hospitales de Rehabilitación/estadística & datos numéricos , Humanos , Italia , Masculino , Persona de Mediana Edad , Estado Vegetativo Persistente/etiología , Estudios Retrospectivos , Índice de Severidad de la EnfermedadAsunto(s)
Antígenos CD34/metabolismo , Antineoplásicos/administración & dosificación , Antineoplásicos/uso terapéutico , Factor Estimulante de Colonias de Granulocitos/administración & dosificación , Movilización de Célula Madre Hematopoyética/métodos , Compuestos Heterocíclicos/uso terapéutico , Linfoma/sangre , Linfoma/tratamiento farmacológico , Adulto , Anciano , Algoritmos , Bencilaminas , Ciclamas , Femenino , Enfermedad de Hodgkin/terapia , Humanos , Linfoma no Hodgkin/terapia , Masculino , Persona de Mediana EdadRESUMEN
BACKGROUND: The lack of knowledge about epidemiological and clinical data of patients with Acquired Brain Injury (ABI) admitted to Rehabilitation facilities in Italy led to the creation, in June 2008, of a data collection on-line registry. AIM: To collect epidemiological and clinical data and to evaluate functional outcome of patients with severe traumatic and non-traumatic ABI admitted to Rehabilitation facilities in Italy between June 2008 and December 2011 and to compare data of patients with ABI of different aetiologies. DESIGN: Observational retrospective study. SETTING: The study involved 29 Italian Rehabilitation facilities. POPULATION: The study enrolled 1469 patients with severe traumatic (TBI) and non-traumatic ABI (NTBI). METHODS: Data collected included demographic (number of patients with TBI and NTBI, gender, age) and clinical characteristics (provenience, number of days elapsed between onset and rehabilitation admission, rehabilitation length of stay, discharge destination, death and vegetative state diagnosis, presence of percutaneous endoscopic gastrostomy, tracheostomy, pressure sores and paraosteoarthropathies). Functional outcome was evaluated using the Disability Rating Scale. RESULTS: Of the whole population studied, 44.31% and 55.69% patients had suffered a TBI and a NTBI, respectively. In the NTBI group 40.09% had a cerebrovascular injury, 12.04% an anoxic brain damage, 3.6% had a brain injury of other causes. The mean age was 43.67 and 56.68 for subjects with TBI and NTBI, respectively. Patients with TBI showed a lower onset-admission interval (OAI), compared with NTBI group; no difference in rehabilitation length of stay (LOS) was recorded between groups. Patients with TBI presented a lower DRS score at admission and discharge and returned home more frequently than NTBI group. CONCLUSIONS: The creation of a National registry allows the collection of data about patients with ABI in order to study the clinical course, the functional outcome and to establish a basis for comparison with other data sources. Clinical Rehabilitation Impact. Data collection could be useful in the evaluation and planning of rehabilitation pathways, and to assess the allocation of healthcare and rehabilitative resources.
Asunto(s)
Lesiones Encefálicas/epidemiología , Lesiones Encefálicas/rehabilitación , Sistema de Registros/estadística & datos numéricos , Centros de Rehabilitación/estadística & datos numéricos , Adolescente , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Lesiones Encefálicas/etiología , Evaluación de la Discapacidad , Femenino , Humanos , Pacientes Internos , Italia/epidemiología , Tiempo de Internación , Masculino , Persona de Mediana Edad , Estado Vegetativo Persistente/epidemiología , Estudios Retrospectivos , Distribución por Sexo , Análisis de Supervivencia , Tiempo de Tratamiento , Índices de Gravedad del Trauma , Resultado del Tratamiento , Adulto JovenRESUMEN
Management of brachial plexus injury sequelae is a challenging issue in neurorehabilitation. In the last decades great strides have been made in the areas of early diagnosis and surgical techniques. Conversely, rehabilitation of brachial plexus injury is a relatively unexplored field. Some critical aspects regarding brachial plexus injury rehabilitation have to be acknowledged. First, brachial plexus injury may result in severe and chronic impairments in both adults and children, thus requiring an early and long-lasting treatment. Second, nerve damage causes a multifaceted clinical picture consisting of sensorimotor disturbances (pain, muscle atrophy, muscle weakness, secondary deformities) as well as reorganization of the Central Nervous System that may be associated with upper limb underuse, even in case of peripheral injured nerves repair. Finally, psychological problems and a lack of cooperation by the patient may limit rehabilitation effects and increase disability. In the present paper the literature concerning brachial plexus injury deficits and rehabilitation in both adults and children was reviewed and discussed. Although further research in this field is recommended, current evidence supports the potential role of rehabilitation in reducing both early and long-lasting disability. Furthermore, the complexity of the functional impairment necessitates an interdisciplinary approach incorporating various health professionals in order to optimizing outcomes.
Asunto(s)
Neuropatías del Plexo Braquial/rehabilitación , Plexo Braquial/lesiones , Evaluación de la Discapacidad , Centros de Rehabilitación , Adulto , Niño , HumanosRESUMEN
Previous studies have demonstrated that astrocytomas express elevated levels of activated Ras.GTP despite the absence of activating Ras mutations. Farnesyl transferase inhibitors (FTIs) exert their antitumor effect in part through inhibition of Ras-mediated signaling. SCH66336 is a potent FTI presently undergoing clinical trials in patients with solid tumors. We evaluated the efficacy of SCH66336 against a panel of eight human astrocytoma cell lines and three human astrocytoma explant xenograft models in NOD-SCID mice. SCH66336 demonstrated variable antiproliferative effects against the cell lines, with IC(50) ranging from 0.6 microM to 32.3 microM. Two of the three human glioblastoma multiforme (GBM) xenografts demonstrated substantial growth inhibition in response to SCH66336, with up to 69% growth inhibition after 21 days of treatment. Drug efficacy could be accurately predicted using a combination of the H-, K-, and N-isotype-specific Ras.GTP levels. These data indicate that the absence of Ras mutations does not preclude chemotherapeutic efficacy by FTIs, that Ras is likely a major target of FTIs regardless of Ras mutational status, and that isotype-specific Ras.GTP levels are a promising marker of drug efficacy.
Asunto(s)
Transferasas Alquil y Aril/antagonistas & inhibidores , Astrocitoma/metabolismo , Neoplasias Encefálicas/metabolismo , Inhibidores Enzimáticos/farmacología , Genes ras/genética , Guanosina Trifosfato/metabolismo , Proteínas de Unión al GTP Monoméricas/metabolismo , Piperidinas/farmacología , Piridinas/farmacología , Proteínas ras/metabolismo , Animales , Astrocitoma/tratamiento farmacológico , Astrocitoma/patología , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/patología , División Celular/efectos de los fármacos , Farnesiltransferasa , Glioblastoma/tratamiento farmacológico , Glioblastoma/metabolismo , Glioblastoma/patología , Humanos , Inmunohistoquímica , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos NOD , Ratones Desnudos , Ratones SCID , Mutación , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de Xenoinjerto , Proteínas ras/genéticaRESUMEN
Vascular endothelial growth factor (VEGF) is a major inducer of tumor angiogenesis and edema in human astrocytomas by its interaction with cognate endothelial-specific receptors (VEGFR1/R2). Tie1 and Tie2/Tek are more recently identified endothelial-specific receptors, with angiopoietins being ligands for the latter. These angiogenic factors and receptors are crucial for the maturation of the vascular system, but their role in tumor angiogenesis, particularly in astrocytomas, is unknown. In this study, we demonstrate that the angiopoietin family member Ang1 is expressed by some of the astrocytoma cell lines. In contrast to VEGF, Ang1 is down regulated by hypoxia. Ang2 was not overexpressed. Expression profiles of low-grade astrocytoma specimens were similar to those of normal brain, with low levels of Ang1, Ang2, and VEGF expression. Glioblastoma multiforme expressed higher levels of Angl, but not to the same degree as pseudopalisading astrocytoma cells around necrotic and hypoxic zones expressed VEGF, as shown in previous studies. Ang2 expression in the highly proliferative tumor vascular endothelium was also increased, as was phosphorylated Tie2/Tek. The expression profile of these angiogenic factors and their endothelial cell receptors in human glioblastomas multiforme was similar to that in a transgenic mouse model of glioblastoma multiforme. These data suggest that both VEGF and angiopoietins are involved in regulating tumor angiogenesis in human astrocytomas.
Asunto(s)
Astrocitoma/metabolismo , Neoplasias Encefálicas/metabolismo , Hipoxia de la Célula/genética , Regulación Neoplásica de la Expresión Génica , Glioblastoma/metabolismo , Glicoproteínas de Membrana/biosíntesis , Neovascularización Fisiológica/genética , Proteínas Tirosina Quinasas Receptoras/metabolismo , Angiopoyetina 1 , Angiopoyetina 2 , Animales , Astrocitoma/genética , Astrocitoma/patología , Western Blotting , Factores de Crecimiento Endotelial/biosíntesis , Glioblastoma/genética , Glioblastoma/patología , Humanos , Técnicas para Inmunoenzimas , Hibridación in Situ , Linfocinas/biosíntesis , Glicoproteínas de Membrana/genética , Ratones , Ratones Endogámicos ICR , Ratones Transgénicos , Biosíntesis de Proteínas , Receptor TIE-2 , Células Tumorales Cultivadas , Factor A de Crecimiento Endotelial Vascular , Factores de Crecimiento Endotelial VascularRESUMEN
Activation of the p21-ras signaling pathway from aberrantly expressed receptors promotes the growth of malignant human astrocytomas. We developed a transgenic mouse astrocytoma model using the glial fibrillary acidic protein (GFAP) promoter to express oncogenic V(12)Ha-ras, specifically in astrocytes. The development of GFAP-immunoreactive astrocytomas was directly proportional to the level of V(12)Ha-ras transgene expression. Chimeras expressing high levels of V(12)Ha-ras in astrocytes died from multifocal malignant astrocytomas within 2 weeks, whereas those with moderate levels went to germ-line transmission. Ninety-five percent of these mice died from solitary or multifocal low- and high-grade astrocytomas within 2-6 months. These transgenic astrocytomas are pathologically similar to human astrocytomas, with a high mitotic index, nuclear pleomorphism, infiltration, necrosis, and increased vascularity. Derivative astrocytoma cells are tumorigenic upon inoculation in another host. The transgenic astrocytomas exhibit additional molecular alterations associated with human astrocytomas, including a decreased or absent expression of p16, p19, and PTEN as well as overexpression of EGFR, MDM2, and CDK4. Cytogenetic analysis revealed consistent clonal aneuploidies of chromosomal regions syntenic with comparable loci altered in human astrocytomas. Therefore, this transgenic mouse astrocytoma model recapitulates many of the molecular histopathological and growth characteristics of human malignant astrocytomas in a reproducible, germ-line-transmitted, and high-penetrance manner.
Asunto(s)
Astrocitos/fisiología , Astrocitoma/genética , Modelos Animales de Enfermedad , Proteínas Proto-Oncogénicas p21(ras)/fisiología , Animales , Astrocitos/metabolismo , Astrocitoma/metabolismo , Astrocitoma/patología , Transformación Celular Neoplásica , Femenino , Dosificación de Gen , Regulación Neoplásica de la Expresión Génica , Proteína Ácida Fibrilar de la Glía/genética , Humanos , Masculino , Ratones , Ratones Endogámicos ICR , Ratones Transgénicos , Plásmidos/genética , Regiones Promotoras Genéticas , Proteínas Proto-Oncogénicas p21(ras)/biosíntesis , Proteínas Proto-Oncogénicas p21(ras)/genéticaRESUMEN
Injury to the central nervous system (CNS) invokes a reparative response known as astrogliosis, characterized largely by hypertrophy, proliferation and increased expression of glial fibrillary acidic protein (GFAP), resulting in reactive astrocytosis. Based on our prior observation that peritumoral reactive astrocytes express Vascular Endothelial Growth Factor (VEGF), a highly potent and specific angiogenic growth factor, we have hypothesized that reactive astrocytosis also contributes to the neovascularization associated with astrogliosis. To evaluate this hypothesis we evaluated human surgical/autopsy specimens from a variety of CNS disorders that induce astrogliosis and an experimental CNS needle injury model in wild type and GFAP:Green Fluorescent Protein (GFP) transgenic mice. Using computer image semi-quantitative analysis we evaluated the number of GFAP-positive reactive astrocytes, degree of VEGF expression by these astrocytes, associated Factor VIII-positive microvascular density (MVD) and Ki-67 proliferating endothelial cells. The degree of reactive astrocytosis correlated to levels of VEGF immunoreactivity and MVD in the neuropathological specimens. The mouse-needle-stick brain injury model demonstrated this correlation was temporally and spatially related and maximal after 1 week. These results, involving both human pathology specimens augmented by experimental animal data, supports our hypothesis that the neoangiogenesis associated with reactive astrogliosis is correlated to increased reactive astrocytosis and associated VEGF expression.
Asunto(s)
Astrocitos , Astrocitos/metabolismo , Factores de Crecimiento Endotelial/metabolismo , Linfocinas/metabolismo , Neovascularización Patológica , Animales , Astrocitos/patología , Encefalopatías/patología , Encefalopatías/fisiopatología , Lesiones Encefálicas/patología , Lesiones Encefálicas/fisiopatología , Proteína Ácida Fibrilar de la Glía/genética , Gliosis/patología , Proteínas Fluorescentes Verdes , Humanos , Indicadores y Reactivos , Proteínas Luminiscentes/genética , Ratones , Ratones Transgénicos/genética , Lesiones por Pinchazo de Aguja/patología , Lesiones por Pinchazo de Aguja/fisiopatología , Factores de Tiempo , Distribución Tisular , Factor A de Crecimiento Endotelial Vascular , Factores de Crecimiento Endotelial VascularRESUMEN
Vascular endothelial growth factor (VEGF), through activation of its endothelial receptors VEGFR-1 and VEGFR-2, is an important positive modulator of tumor angiogenesis and edema in solid tumors such as malignant astrocytomas. Neuropilin-1 (Npn-1) is a transmembrane receptor expressed by both endothelial and non-endothelial cells, including tumor cells. Npn-1 has been postulated to function as a co-factor in activation of the biologically relevant VEGFR-2, by the most abundant VEGF165 isoform. However, the function of Npn-1 in normal and pathological angiogenesis, its expression pattern in relation to VEGF in tumors such as astrocytomas and whether it is similarly or differentially regulated compared to VEGF remain unknown. In our study, the expression pattern of Npn-1 and VEGF by human astrocytoma cell lines and specimens was closely correlated and associated with malignant astrocytomas. Mitogens, such as epidermal growth factor and activation of p21-Ras, previously demonstrated to be relevant in astrocytoma proliferation and induction of VEGF, also induce Npn-1 expression. Hypoxia, the main physiological inducer of VEGF expression, decreased Npn-1 expression. Increased Npn-1 expression was also demonstrated in a transgenic mouse astrocytoma model. Astrocytomas are an ideal system for furthering our understanding of the functional relevance, if any, of Npn-1 in tumor angiogenesis.
Asunto(s)
Astrocitoma/genética , Factores de Crecimiento Endotelial/genética , Regulación Neoplásica de la Expresión Génica , Linfocinas/genética , Proteínas del Tejido Nervioso/genética , Animales , Neoplasias de la Mama , Hipoxia de la Célula , Neoplasias del Colon , Factor de Crecimiento Epidérmico/farmacología , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Genes ras , Humanos , Glicoproteínas de Membrana/genética , Ratones , Ratones Transgénicos , Neuropilina-1 , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Proteínas Recombinantes/farmacología , Células Tumorales Cultivadas , Factor A de Crecimiento Endotelial Vascular , Factores de Crecimiento Endotelial VascularRESUMEN
Neurofibromatosis 1 (NF1) is a common autosomal dominant cancer predisposition syndrome, in which 15% to 20% of affected individuals develop astrocytomas. Neurofibromin, the protein product of the NF1 gene, functions as a tumor suppressor, largely by inhibiting Ras activity. While loss of neurofibromin has been implicated in the molecular pathogenesis of other NF1-associated tumors, there is no formal evidence demonstrating loss of neurofibromin function in NF1-associated astrocytomas. In this report, we describe an NF1 patient from whom both astrocytoma tumor tissue as well as corresponding non-neoplastic white matter were available for analysis. Loss of neurofibromin expression was observed in the tumor and was associated with elevated levels of Ras-GTP. However, elevated Ras-GTP levels were not the result of oncogenic Ras mutations, altered p120-GAP function, growth factor receptor activation, or abnormal p53, Rb, or p16 expression. Furthermore, increased Raf-MAPK and PI3-K/Akt activity was detected in the NF1 astrocytoma compared with the corresponding normal white matter. These results support a role for neurofibromin as the critical GAP in the molecular pathogenesis of NF1 astrocytomas.
Asunto(s)
Astrocitoma/genética , Neoplasias Encefálicas/genética , Encéfalo/metabolismo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteínas del Tejido Nervioso/genética , Neurofibromatosis 1/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas , Proteínas Proto-Oncogénicas/metabolismo , Adulto , Astrocitoma/metabolismo , Astrocitoma/patología , Encéfalo/patología , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patología , Mapeo Cromosómico , Cromosomas Humanos Par 17 , Humanos , Pérdida de Heterocigocidad , Imagen por Resonancia Magnética , Masculino , Proteínas del Tejido Nervioso/deficiencia , Neurofibromatosis 1/metabolismo , Neurofibromatosis 1/patología , Neurofibromina 1 , Proteínas Proto-Oncogénicas c-akt , Transducción de Señal , Proteínas Activadoras de ras GTPasa/metabolismoRESUMEN
OBJECTIVE: Amplification of the epidermal growth factor receptor (EGFR) is a common event in the molecular pathogenesis of high-grade astrocytic tumors, occurring in 50% of glioblastoma multiforme (GBM) cases. A subset of GBMs also express a constitutively phosphorylated truncated receptor (EGFRvIII). Expression of transfected EGFRvIII in cells has been reported to activate the Ras-mitogen-activated protein kinase pathway and to provide a growth advantage. Novel therapeutic agents targeting signal transduction pathways are entering early clinical trials; determination of which GBMs express EGFRvIII might help identify patients who might benefit from these biological agents. METHODS: A cohort of 15 flash-frozen surgical specimens (12 GBMs, 2 gliosarcomas, and 1 adult low-grade glioma) were evaluated for EGFR and EGFRvIII expression and for EGFR activation status using immunohistochemical (IHC) analysis, Western blotting, and reverse transcription-polymerase chain reaction assays. Levels of activated Ras-guanosine triphosphate were measured using a nonradioactive luciferase-based technique. Mitogen-activated protein kinase activation was determined using a myelin basic protein assay. IHC analysis was performed on paraffin-embedded, formalin-fixed, pathological specimens. Normal control samples included white matter specimens distal to tumors (n = 5), a sample obtained during a lobectomy for treatment of epilepsy (n = 1), and cultured fetal human astrocytes (n = 1). RESULTS: We demonstrated higher levels of activated Ras and mitogen-activated protein kinase in GBM specimens, compared with normal brain tissue or the low-grade glioma. There was a very good correlation between results obtained using specialized molecular techniques and those obtained using routine IHC techniques. Screening for EGFRvIII expression may be of prognostic importance, because patients with EGFRvIII-positive tumors exhibited shorter life expectancies (mean survival time for patients with EGFRvIII-positive tumors, 4.5 +/- 0.6 mo; mean survival time for patients with EGFRvIII-negative tumors, 11.2 +/- 0.9 mo). CONCLUSION: We demonstrated that routine IHC techniques using commercially available antibodies are capable of identifying which GBM specimens express EGFRvIII and whether the EGFRs are activated. Such a molecular classification of GBMs might allow us to determine which patients might benefit from biologically targeted therapies. In addition, characterization of specimens with respect to their EGFRvIII status seems to be of prognostic value.
Asunto(s)
Biomarcadores de Tumor/genética , Neoplasias Encefálicas/patología , Receptores ErbB/genética , Glioblastoma/patología , Proteínas Quinasas/genética , Proteínas ras/genética , Adulto , Anciano , Astrocitoma/genética , Astrocitoma/patología , Encéfalo/patología , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/mortalidad , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/patología , Corteza Cerebral/fisiología , Femenino , Regulación Neoplásica de la Expresión Génica/fisiología , Glioblastoma/genética , Glioblastoma/mortalidad , Gliosarcoma/genética , Gliosarcoma/patología , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Tasa de SupervivenciaRESUMEN
Neurogenic sarcomas are incurable, common malignant human peripheral nerve tumors subject to local recurrence and systemic metastasis. In this study, the vascularity, vascular endothelial growth factor (VEGF) expression, and effects of inhibiting VEGF receptor on growth of neurogenic sarcomas were examined. Vascularization and VEGF expression were 6.4- and 15-fold higher in tumors than in normal nerves. The small molecule inhibitor (SU5416) of VEGF receptor 2 had no effect on neurogenic sarcoma cell lines in vitro, but the growth of a human tumor explant xenograft model was reduced by 54.8% compared to vehicle. Reduction in tumor growth was due to decreased tumor angiogenesis, leading to reduction of tumor cell proliferation and increased apoptosis. Inhibiting VEGF function may therefore be a useful adjuvant therapy for neurogenic sarcomas.
Asunto(s)
Inhibidores de la Angiogénesis/farmacología , Neovascularización Patológica/prevención & control , Neurofibromatosis 1/tratamiento farmacológico , Proteínas Tirosina Quinasas Receptoras/antagonistas & inhibidores , Receptores de Factores de Crecimiento/antagonistas & inhibidores , Sarcoma/tratamiento farmacológico , Animales , Quimioterapia Adyuvante , Relación Dosis-Respuesta a Droga , Factores de Crecimiento Endotelial/metabolismo , Inhibidores Enzimáticos/farmacología , Indoles/farmacología , Linfocinas/metabolismo , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , Metástasis de la Neoplasia/prevención & control , Recurrencia Local de Neoplasia/prevención & control , Trasplante de Neoplasias , Neuronas/metabolismo , Pirroles/farmacología , Receptores de Factores de Crecimiento Endotelial Vascular , Factores de Tiempo , Células Tumorales Cultivadas , Factor A de Crecimiento Endotelial Vascular , Factores de Crecimiento Endotelial VascularRESUMEN
Targeted disruption of the single mutant K-ras allele in two human colorectal carcinoma cell lines (DLD-1 and HCT-116) leads to loss of tumorigenic competence in nude mice with retention of ability to grow indefinitely in monolayer culture. Because expression of the mutant K-ras oncogene in these cell lines is associated with marked up-regulation of vascular endothelial growth factor/vascular permeability factor (VEGF/VPF), we sought to determine whether this potent angiogenesis inducer plays a role in K-ras-dependent tumorigenic competence. Transfection of a VEGF121 antisense expression vector into DLD-1 and HCT-116 cells resulted in suppression of VEGF/VPF production by a factor of 3- to 4-fold. The VEGF/VPF-deficient sublines, unlike the parental population or vector controls, were profoundly suppressed in their ability to form tumors in nude mice for as long as 6 months after cell injection. In contrast, in vitro growth of these sublines was unaffected, thus demonstrating the critical importance of VEGF/VPF as an angiogenic factor for HCT-116 and DLD-1 cells. Transfection of a full-length VEGF121 cDNA into two nontumorigenic mutant K-ras knockout sublines resulted in a weak but detectable restoration of tumorigenic ability in vivo in a subset of the transfectants, with no consistent change in growth properties in vitro. The findings indicate that mutant ras-oncogene-dependent VEGF/VPF expression is necessary, but not sufficient, for progressive tumor growth in vivo and highlight the relative contribution of oncogenes, such as mutant K-ras, to the process of tumor angiogenesis.
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Carcinoma/irrigación sanguínea , Carcinoma/genética , Neoplasias Colorrectales/irrigación sanguínea , Neoplasias Colorrectales/genética , Factores de Crecimiento Endotelial/genética , Regulación Neoplásica de la Expresión Génica , Genes ras , Linfocinas/genética , Neovascularización Patológica/genética , Animales , Humanos , Ratones , Mutación , Células Tumorales Cultivadas , Regulación hacia Arriba , Factor A de Crecimiento Endotelial Vascular , Factores de Crecimiento Endotelial VascularRESUMEN
Breast cancer is the second leading cause of cancer death in North American women. There is considerable need for reliable prognostic markers to assist clinicians in making management decisions. Although a variety of factors have been tested, only tumor stage, grade, size, hormone receptor status, and S-phase fraction are used on a routine basis. The cell cycle is governed by a family of cyclin-dependent kinases (cdks), which are regulated by associated cyclins and by phosphorylation. p27Kip1, a cyclin-dependent kinase inhibitor, regulates progression from G1 into S phase by binding and inhibiting cyclin/cdks. p27Kip1 protein levels and/or activity are upregulated by growth inhibitory cytokines including transforming growth factor-beta (TGF-beta) and, thus, provide an important link between extracellular regulators and the cell cycle. Loss of p27Kip1, a negative cell-cycle regulator, may contribute to oncogenesis and tumor progression. However, p27Kip1 mutations in human tumors are extremely rare. We have demonstrated by immunohistochemistry that p27Kip1 protein levels are reduced in primary breast cancers and that this is associated with tumor progression in both in situ and invasive lesions. This was confirmed by western analysis, reflected in increased G1/S-phase cyclin-dependent kinase activities and shown to be regulated posttranscriptionally by in situ hybridization. Furthermore, on multivariate analysis, low p27Kip1 is a predictor of reduced disease-free survival. This simple and reliable immunohistochemical assay may become a routine part of breast cancer evaluation and may influence patient management.