RESUMEN
The National Cancer Institute (NCI) K99/R00 award is intended to help postdoctoral scholars transition in a timely manner to research independence and to foster their development of an impactful cancer research program that is competitive for subsequent independent funding. Here we analyzed factors that impact peer review outcomes and evaluated whether NCI K99/R00 awardees have achieved the goals of the K99/R00 funding mechanism. Our analysis of the K99/R00 review criterion scores demonstrates that while all review criterion scores are positively correlated with the overall impact score, the Research Plan criterion is the strongest predictor of the overall impact score and funding outcomes. In addition, our analysis shows the NCI K99/R00 award facilitated the successful transition of postdoctoral scholars to research independence and enhanced the likelihood of K99/R00 awardees to secure subsequent R01-equivalent NIH grant support although not in an accelerated fashion as originally intended. An NCI K99/R00 award was not determined to be a prerequisite to obtain a faculty position, but for some awardees, it was an asset in that transition. Our results suggest that the NCI K99/R00 award is an important component for training and retention of the next generation of independent cancer researchers and to increasing the percentage of women and promoting the diversity of the cancer research workforce.
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Distinciones y Premios , National Cancer Institute (U.S.) , Estados Unidos , Humanos , Investigación Biomédica , Apoyo a la Investigación como Asunto , Evaluación de Programas y Proyectos de Salud , NeoplasiasRESUMEN
Solving health problems requires not only the development of new medical knowledge but also its dissemination, particularly to underserved communities. The barriers to effective dissemination also contribute to the disparities in cancer care experienced most everywhere. This concern is particularly acute in low and middle-income countries which already bear a disproportionate burden of cancer, a situation that is projected to worsen. Project ECHO (Extension for Community Healthcare Outcomes) is a knowledge dissemination platform that can increase workforce capacity across many fields, including cancer care by scaling best practices. Here we describe how Project ECHO works and illustrate this with existing programs that span the cancer care continuum and the globe. The examples provided combined with the explanation of how to build effective Project ECHO communities provide an accessible guide on how this education strategy can be integrated into existing work to help respond to the challenge of cancer.
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Servicios de Salud Comunitaria , Neoplasias , HumanosRESUMEN
Cancer incidence and mortality are increasing in low- and middle-income countries (LMICs), where more than 75% of global cancer burden will occur by the year 2040. The primary drivers of cancer morbidity and mortality in LMICs are environmental and behavioral risk factors, inadequate prevention and early detection services, presence of comorbidities, and poor access to treatment and palliation. These same drivers also contribute to marked cancer health disparities in high-income countries. Studying cancer in LMICs provides opportunities to better understand and address these drivers to benefit populations worldwide, and reflecting this, global oncology as an academic discipline has grown substantially in recent years. However, sustaining this growth requires a uniquely trained workforce with the skills to pursue relevant, rigorous, and equitable global oncology research. Despite this need, dedicated global cancer research training programs remain somewhat nascent and uncoordinated. In this paper, we discuss efforts to address these gaps in global cancer research training at the US National Institutes of Health.
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Creación de Capacidad , Neoplasias , Países en Desarrollo , Salud Global , Humanos , Renta , Oncología Médica , Neoplasias/prevención & control , PobrezaRESUMEN
The RET proto-oncogene, a tyrosine kinase receptor, is widely known for its essential role in cell survival. Germ line missense mutations, which give rise to constitutively active oncogenic RET, were found to cause multiple endocrine neoplasia type 2, a dominant inherited cancer syndrome that affects neuroendocrine organs. However, the mechanisms by which RET promotes cell survival and prevents cell death remain elusive. We demonstrate that in addition to cytoplasmic localization, RET is localized in the nucleus and functions as a tyrosine-threonine dual specificity kinase. Knockdown of RET by shRNA in medullary thyroid cancer-derived cells stimulated expression of activating transcription factor 4 (ATF4), a master transcription factor for stress-induced apoptosis, through activation of its target proapoptotic genes NOXA and PUMA. RET knockdown also increased sensitivity to cisplatin-induced apoptosis. We observed that RET physically interacted with and phosphorylated ATF4 at tyrosine and threonine residues. Indeed, RET kinase activity was required to inhibit the ATF4-dependent activation of the NOXA gene because the site-specific substitution mutations that block threonine phosphorylation increased ATF4 stability and activated its targets NOXA and PUMA. Moreover, chromatin immunoprecipitation assays revealed that ATF4 occupancy increased at the NOXA promoter in TT cells treated with tyrosine kinase inhibitors or the ATF4 inducer eeyarestatin as well as in RET-depleted TT cells. Together these findings reveal RET as a novel dual kinase with nuclear localization and provide mechanisms by which RET represses the proapoptotic genes through direct interaction with and phosphorylation-dependent inactivation of ATF4 during the pathogenesis of medullary thyroid cancer.
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Factor de Transcripción Activador 4/metabolismo , Apoptosis , Proteínas Proto-Oncogénicas c-ret/metabolismo , Factor de Transcripción Activador 4/química , Transporte Activo de Núcleo Celular/efectos de los fármacos , Apoptosis/efectos de los fármacos , Proteínas Reguladoras de la Apoptosis/genética , Línea Celular Tumoral , Núcleo Celular/efectos de los fármacos , Núcleo Celular/metabolismo , Cisplatino/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Fosforilación/efectos de los fármacos , Regiones Promotoras Genéticas/genética , Inhibidores de Proteínas Quinasas/farmacología , Proteolisis/efectos de los fármacos , Proto-Oncogenes Mas , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas c-bcl-2/genética , Treonina/metabolismo , Transcripción Genética/efectos de los fármacosRESUMEN
BACKGROUND: The majority of glioblastomas have aberrant receptor tyrosine kinase (RTK)/RAS/phosphoinositide 3 kinase (PI3K) signaling pathways and malignant glioma cells are thought to be addicted to these signaling pathways for their survival and proliferation. However, recent studies suggest that monotherapies or inappropriate combination therapies using the molecular targeted drugs have limited efficacy possibly because of tumor heterogeneities, signaling redundancy and crosstalk in intracellular signaling network, indicating necessity of rationale and methods for efficient personalized combination treatments. Here, we evaluated the growth of colonies obtained from glioma tumor-initiating cells (GICs) derived from glioma sphere culture (GSC) in agarose and examined the effects of combination treatments on GICs using targeted drugs that affect the signaling pathways to which most glioma cells are addicted. METHODS: Human GICs were cultured in agarose and treated with inhibitors of RTKs, non-receptor kinases or transcription factors. The colony number and volume were analyzed using a colony counter, and Chou-Talalay combination indices were evaluated. Autophagy and apoptosis were also analyzed. Phosphorylation of proteins was evaluated by reverse phase protein array and immunoblotting. RESULTS: Increases of colony number and volume in agarose correlated with the Gompertz function. GICs showed diverse drug sensitivity, but inhibitions of RTK and RAF/MEK or PI3K by combinations such as EGFR inhibitor and MEK inhibitor, sorafenib and U0126, erlotinib and BKM120, and EGFR inhibitor and sorafenib showed synergy in different subtypes of GICs. Combination of erlotinib and sorafenib, synergistic in GSC11, induced apoptosis and autophagic cell death associated with suppressed Akt and ERK signaling pathways and decreased nuclear PKM2 and ß-catenin in vitro, and tended to improve survival of nude mice bearing GSC11 brain tumor. Reverse phase protein array analysis of the synergistic treatment indicated involvement of not only MEK and PI3K signaling pathways but also others associated with glucose metabolism, fatty acid metabolism, gene transcription, histone methylation, iron transport, stress response, cell cycle, and apoptosis. CONCLUSION: Inhibiting RTK and RAF/MEK or PI3K could induce synergistic cytotoxicity but personalization is necessary. Examining colonies in agarose initiated by GICs from each patient may be useful for drug sensitivity testing in personalized cancer therapy.
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Glioma/tratamiento farmacológico , Glioma/patología , Quinasas de Proteína Quinasa Activadas por Mitógenos/antagonistas & inhibidores , Células Madre Neoplásicas/patología , Inhibidores de las Quinasa Fosfoinosítidos-3 , Inhibidores de Proteínas Quinasas/uso terapéutico , Quinasas raf/antagonistas & inhibidores , Animales , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Apoptosis/efectos de los fármacos , Autofagia/efectos de los fármacos , Biomarcadores de Tumor/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Sinergismo Farmacológico , Humanos , Concentración 50 Inhibidora , Masculino , Ratones Desnudos , Quinasas de Proteína Quinasa Activadas por Mitógenos/metabolismo , Células Madre Neoplásicas/efectos de los fármacos , Células Madre Neoplásicas/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Transducción de Señal/efectos de los fármacos , Quinasas raf/metabolismoRESUMEN
Signal transducer and activator of transcription 5b (STAT5b) is likely the relevant STAT5 isoform with respect to the process of malignant progression in gliomas. STAT5b is a latent cytoplasmic protein involved in cell signaling through the modulation of growth factors, apoptosis, and angiogenesis. Previous in vitro studies have shown increased STAT5b expression in glioblastomas relative to low-grade tumors and normal brain. We recently demonstrated that phosphorylated STAT5b associates with delta epidermal growth factor receptor in the nucleus and subsequently binds the promoters of downstream effector molecules, including aurora kinase A. Analysis of TCGA dataset reveals that STAT5b is predominantly expressed in proneural (PN) gliomas relative to mesenchymal and neural gliomas. Here, we modeled ectopic expression of STAT5b in vivo using a platelet-derived growth factor subunit B (PDGFB)-dependent mouse model of PN glioma to determine its effect on tumor formation and progression. We showed that coexpression of STAT5b and PDGFB in mice yielded a significantly higher rate of high-grade gliomas than PDGFB expression alone. We also observed shorter survival in the combined expression set. High-grade tumors from the STAT5b + PDGFB expression set were found to have a lower rate of apoptosis than those from PDGFB alone. Furthermore, we showed that increased expression of STAT5b + PDGFB led to increased expression of downstream STAT5b targets, including Bcl-xL, cyclin D1 and aurora kinase A in high-grade tumors when compared to tumors derived from PDGFB alone. Our findings show that STAT5b promotes the malignant transformation of gliomas, particularly the PN subtype, and is a potential therapeutic target.
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Apoptosis/genética , Glioma/genética , Glioma/metabolismo , Proteínas Proto-Oncogénicas c-sis/genética , Proteínas Proto-Oncogénicas c-sis/metabolismo , Factor de Transcripción STAT5/genética , Factor de Transcripción STAT5/metabolismo , Animales , Aurora Quinasa A/genética , Aurora Quinasa A/metabolismo , Proliferación Celular/genética , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Transformación Celular Neoplásica/patología , Ciclina D1/genética , Ciclina D1/metabolismo , Progresión de la Enfermedad , Supervivencia sin Enfermedad , Glioma/patología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Transgénicos/genética , Ratones Transgénicos/metabolismoRESUMEN
ΔEGFR is a potent glioblastoma oncogene which has been studied primarily as a plasma membrane kinase. Using intracranial xenograft studies in mice, we show that blocking ΔEGFR access to the nucleus attenuates its tumorigenicity and, conversely, that promoting nuclear accumulation enhances this, providing the first in vivo evidence that the nuclear actions of ΔEGFR contribute strongly to its oncogenic function. Nuclear actions of ΔEGFR include regulation of gene expression by participation in chromatin-bound complexes, and genome-wide mapping of these sequences by chromatin immunoprecipitation and massively parallel sequencing identified 2294 peaks. Bioinformatic analysis showed enrichment of the E-box motif in the dataset, and c-Myc and ΔEGFR were corecruited to the promoters of and transcriptionally activated a subset of nuclear ΔEGFR chromatin targets. Knockdown of c-Myc decreased the expression of these targets and diminished ΔEGFR-stimulated anchorage-independent colony formation. We conclude that transcriptional regulation of target genes by association with gene regulatory chromatin in cooperation with c-Myc by nuclear ΔEGFR makes a unique contribution to its oncogenicity and propose that this venue provides new targets for therapeutic intervention.
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Núcleo Celular/metabolismo , Transformación Celular Neoplásica/metabolismo , Receptores ErbB/metabolismo , Mutación/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Secuencia de Aminoácidos , Animales , Sitios de Unión , Transformación Celular Neoplásica/patología , Inmunoprecipitación de Cromatina , Elementos E-Box/genética , Receptores ErbB/química , Genoma Humano/genética , Glioma/metabolismo , Humanos , Ratones , Ratones Desnudos , Proteínas Mutantes/metabolismo , Señales de Exportación Nuclear , Señales de Localización Nuclear/metabolismo , Fenotipo , Regiones Promotoras Genéticas/genética , Unión Proteica , Multimerización de Proteína , Transporte de Proteínas , Factores de Transcripción/metabolismoRESUMEN
Despite extensive investigations of Cbl-interacting protein of 85 kDa (CIN85) in receptor trafficking and cytoskeletal dynamics, little is known about its functions in vivo. Here, we report the study of a mouse deficient of the two CIN85 isoforms expressed in the central nervous system, exposing a function of CIN85 in dopamine receptor endocytosis. Mice lacking CIN85 exon 2 (CIN85(Deltaex2)) show hyperactivity phenotypes, characterized by increased physical activity and exploratory behaviour. Interestingly, CIN85(Deltaex2) animals display abnormally high levels of dopamine and D2 dopamine receptors (D2DRs) in the striatum, an important centre for the coordination of animal behaviour. Importantly, CIN85 localizes to the post-synaptic compartment of striatal neurons in which it co-clusters with D2DRs. Moreover, it interacts with endocytic regulators such as dynamin and endophilins in the striatum. Absence of striatal CIN85 causes insufficient complex formation of endophilins with D2DRs in the striatum and ultimately decreased D2DR endocytosis in striatal neurons in response to dopamine stimulation. These findings indicate an important function of CIN85 in the regulation of dopamine receptor functions and provide a molecular explanation for the hyperactive behaviour of CIN85(Deltaex2) mice.
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Conducta Animal/fisiología , Endocitosis/fisiología , Proteínas de Neoplasias/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Isoformas de Proteínas/metabolismo , Receptores de Dopamina D2/metabolismo , Proteínas Adaptadoras Transductoras de Señales , Animales , Encéfalo/anatomía & histología , Encéfalo/metabolismo , Agonistas de Dopamina/metabolismo , Antagonistas de Dopamina/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Ratones , Ratones Noqueados , Actividad Motora/fisiología , Proteínas de Neoplasias/genética , Proteínas del Tejido Nervioso/genética , Neuronas/citología , Neuronas/metabolismo , Isoformas de Proteínas/genética , Receptores de Dopamina D2/genéticaRESUMEN
BACKGROUND: Despite the growing incidence of cancer worldwide, there are an insufficient number of primary care physicians, community oncologists, and surgeons to meet the demand for cancer care, especially in rural and other medically underserved areas. Teleoncology, including diagnostics, treatment, and supportive care, has the potential to enhance access to cancer care and to improve clinician education and training. OBJECTIVES: Major cancer centers such as The University of Texas MD Anderson Cancer Center must determine how teleoncology will be used as part of strategic planning for the future. The Telemedicine and Telesurgery in Cancer Care (TTCC) conference was convened to determine technologically based strategies for addressing global access to essential cancer care services. RESULTS: The TTCC conference brought policy makers together with physicians, legal and regulatory experts to define strategies to optimize available resources, including teleoncology, to advance global cancer care. CONCLUSIONS: The TTCC conference discourse provided insight into the present state of access to care, expertise, training, technology and other interventions, including teleoncology, currently available through MD Anderson, as well as a vision of what might be achievable in the future, and proposals for moving forward with a comprehensive strategy.
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Oncología Médica , Neoplasias/cirugía , Telemedicina , Humanos , Telemedicina/economía , Telemedicina/legislación & jurisprudenciaRESUMEN
BACKGROUND: Solid tumors present a panoply of genomic alterations, from single base changes to the gain or loss of entire chromosomes. Although aberrations at the two extremes of this spectrum are readily defined, comprehensive discernment of the complex and disperse mutational spectrum of cancer genomes remains a significant challenge for current genome analysis platforms. In this context, high throughput, single molecule platforms like Optical Mapping offer a unique perspective. RESULTS: Using measurements from large ensembles of individual DNA molecules, we have discovered genomic structural alterations in the solid tumor oligodendroglioma. Over a thousand structural variants were identified in each tumor sample, without any prior hypotheses, and often in genomic regions deemed intractable by other technologies. These findings were then validated by comprehensive comparisons to variants reported in external and internal databases, and by selected experimental corroborations. Alterations range in size from under 5 kb to hundreds of kilobases, and comprise insertions, deletions, inversions and compound events. Candidate mutations were scored at sub-genic resolution and unambiguously reveal structural details at aberrant loci. CONCLUSIONS: The Optical Mapping system provides a rich description of the complex genomes of solid tumors, including sequence level aberrations, structural alterations and copy number variants that power generation of functional hypotheses for oligodendroglioma genetics.
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Genómica/métodos , Oligodendroglioma/genética , Mapeo Físico de Cromosoma/métodos , Adulto , Anciano , Secuencia de Bases , Cromosomas Humanos Par 1/genética , Cromosomas Humanos Par 19/genética , Variaciones en el Número de Copia de ADN/genética , Femenino , Humanos , Mutación , Reacción en Cadena de la Polimerasa , Polimorfismo de Nucleótido Simple/genética , Reproducibilidad de los ResultadosRESUMEN
Aberrant EGFR signaling strongly promotes glioma malignancy and treatment resistance. The most prevalent mutation, ΔEGFR/EGFRvIII, is an in-frame deletion of the extracellular domain, which occurs in more than 25% of glioblastomas and enhances growth and survival of tumor cells. Paradoxically, the signaling of the potent oncogene ΔEGFR is of low intensity, raising the question of whether it exhibits preferential signaling to key downstream targets. We have observed levels of phosphorylation of STAT5 at position Y699 in cells expressing ΔEGFR that are similar or higher than in cells that overexpress EGFR and are acutely stimulated with EGF, prompting us to investigate the role of STAT5 activation in glioblastoma. Here, we show that in human glioblastoma samples, pSTAT5 levels correlated positively with EGFR expression and were associated with reduced survival. Interestingly, the activation of STAT5b downstream of ΔEGFR was dependent on SFKs, while the signal from acutely EGF-stimulated EGFR to STAT5b involved other kinases. Phosphorylated STAT5b and ΔEGFR associated in the nucleus, bound DNA and were found on promoters known to be regulated by STAT5 including that of the Aurora A gene. ΔEGFR cooperated with STAT5b to regulate the Bcl-XL promoter and knockdown of STAT5b suppressed anchorage independent growth, reduced the levels of Bcl-XL and sensitized glioblastoma cells to cisplatin. Together these results delineate a novel association of nuclear ΔEGFR with STAT5b, which promotes oncogenesis and treatment resistance in glioblastoma by direct regulation of anti-apoptotic gene, Bcl-XL.
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Receptores ErbB/metabolismo , Glioblastoma/metabolismo , Glioblastoma/patología , Factor de Transcripción STAT5/metabolismo , Proteína bcl-X/genética , Animales , Apoptosis/genética , Aurora Quinasa A , Aurora Quinasas , Línea Celular Tumoral , Núcleo Celular/metabolismo , Supervivencia Celular , Cisplatino/farmacología , Glioblastoma/genética , Humanos , Ratones , Fosforilación , Regiones Promotoras Genéticas , Proteínas Serina-Treonina Quinasas/genética , Interferencia de ARN , ARN Interferente Pequeño , Factor de Transcripción STAT5/genética , Eliminación de Secuencia , Transducción de Señal/genética , Familia-src Quinasas/metabolismoRESUMEN
Malignant glioma is the most common and deadly brain tumor. A marked reduction in the levels of sGC (soluble guanylyl cyclase) transcript in the human glioma specimens has been revealed in our previous studies. In the present study, restoring the expression of sGCß1 alone repressed the aggressive course of glioma. The antitumor effect of sGCß1 was not associated with enzymatic activity of sGC since overexpression of sGCß1 alone did not influence the level of cyclic GMP. Additionally, sGCß1-induced inhibition of the growth of glioma cells was not influenced by treatment with sGC stimulators or inhibitors. The present study is the first to reveal that sGCß1 migrated into the nucleus and interacted with the promoter of the TP53 gene. Transcriptional responses induced by sGCß1 caused the G0 cell cycle arrest of glioblastoma cells and inhibition of tumor aggressiveness. sGCß1 overexpression impacted signaling in glioblastoma multiforme, including the promotion of nuclear accumulation of p53, a marked reduction in CDK6, and a significant decrease in integrin α6. These anticancer targets of sGCß1 may represent clinically important regulatory pathways that contribute to the development of a therapeutic strategy for cancer treatment.
RESUMEN
The cucurbitacins are tetracyclic triterpenes found in plants of the family Cucurbitaceae. Cucurbitacins have been shown to have anti-cancer and anti-inflamatory activities. We investigated the anti-cancer activity of cucurbitacin B extracted from Thai medicinal plant Trichosanthes cucumerina Linn. Cell viability was assessed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Results indicated that cucurbitacin B from T. cucumerina Linn. has a cytotoxic effect on breast cancer cell lines SKBR-3 and MCF-7 with an IC50 of 4.60 and 88.75 µg/ml, respectively. Growth inhibition was attributed to G2/M phase arrest and apoptosis. Cyclin D1, c-Myc, and ß-catenin expression levels were reduced. Western blot analysis showed increased PARP cleavage and decreased Wnt-associated signaling molecules ß-catenin, galectin-3, cyclin D1 and c-Myc, and corresponding changes in phosphorylated GSK-3ß levels. Cucurbitacin B treatment inhibited translocation to the nucleus of ß-catenin and galectin-3. The depletion of ß-catenin and galectin-3 in the nucleus was confirmed by cellular protein fractionation. T-cell factor (TCF)/lymphoid enhancer factor (LEF)-dependent transcriptional activity was disrupted in cucurbitacin B treated cells as tested by a TCF reporter assay. The relative luciferase activity was reduced when we treated cells with cucurbitacin B compound for 24 h. Our data suggest that cucurbitacin B may in part induce apoptosis and exert growth inhibitory effect via interruption the Wnt signaling.
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Galectina 3/metabolismo , Triterpenos/farmacología , Proteínas Wnt/metabolismo , Vía de Señalización Wnt/efectos de los fármacos , beta Catenina/metabolismo , Apoptosis/efectos de los fármacos , Neoplasias de la Mama/metabolismo , Ciclo Celular/efectos de los fármacos , Puntos de Control del Ciclo Celular , Línea Celular Tumoral/efectos de los fármacos , Núcleo Celular/metabolismo , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Ciclina D1/metabolismo , Femenino , Glucógeno Sintasa Quinasa 3/biosíntesis , Glucógeno Sintasa Quinasa 3/metabolismo , Glucógeno Sintasa Quinasa 3 beta , Humanos , Extractos Vegetales/farmacología , Poli(ADP-Ribosa) Polimerasas/metabolismo , Transporte de Proteínas , Proteínas Proto-Oncogénicas c-myc/metabolismo , Factores de Transcripción TCF/antagonistas & inhibidores , Factores de Transcripción TCF/metabolismo , TrichosanthesRESUMEN
An in-frame deletion mutation in Epidermal Growth Receptor (EGFR), ΔEGFR is a common and potent oncogene in glioblastoma (GBM), promoting growth and survival of cancer cells. This mutated receptor is ligand independent and constitutively active. Its activity is low in intensity and thought to be qualitatively different from acutely ligand stimulated wild-type receptor implying that the preferred downstream targets of ΔEGFR play a significant role in malignancy. To understand the ΔEGFR signal, we compared it to that of a kinase-inactivated mutant of ΔEGFR and wild-type EGFR with shotgun phosphoproteomics using an electron-transfer dissociation (ETD) enabled ion trap mass spectrometer. We identified and quantified 354 phosphopeptides corresponding to 249 proteins. Among the ΔEGFR-associated phosphorylations were the previously described Gab1, c-Met and Mig-6, and also novel phosphorylations including that of STAT5 on Y694/9. We have confirmed the most prominent phosphorylation events in cultured cells and in murine xenograft models of glioblastoma. Pathway analysis of these proteins suggests a preference for an alternative signal transduction pathway by ΔEGFR compared to wild-type EGFR. This understanding will potentially benefit the search for new therapeutic targets for ΔEGFR expressing tumors.
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Receptores ErbB/genética , Receptores ErbB/metabolismo , Glioblastoma/metabolismo , Fosfotirosina/metabolismo , Factor de Transcripción STAT5/metabolismo , Transducción de Señal/fisiología , Animales , Línea Celular Tumoral , Humanos , Ratones , Ratones Desnudos , Mutación , Trasplante de Neoplasias , Neoplasias/genética , Neoplasias/metabolismo , Fosfopéptidos/análisis , Espectrometría de Masas en Tándem/métodosRESUMEN
The NO and cGMP signaling pathways are of broad physiological and pathological significance. We compared the NO/soluble guanylyl cyclase (sGC)/cGMP pathway in human glioma tissues and cell lines with that of healthy control samples and demonstrated that sGC expression is significantly lower in glioma preparations. Our analysis of GEO databases (National Cancer Institute) further revealed a statistically significant reduction of sGC transcript levels in human glioma specimens. On the other hand, the expression levels of particulate (membrane) guanylyl cyclases (pGC) and cGMP-specific phosphodiesterase (PDE) were intact in the glioma cells that we have tested. Pharmacologically manipulating endogenous cGMP generation in glioma cells through either stimulating pGC by ANP/BNP, or blocking PDE by 3-isobutyl-1-methylxanthine/zaprinast caused significant inhibition of proliferation and colony formation of glioma cells. Genetically restoring sGC expression also correlated inversely with glioma cells growth. Orthotopic implantation of glioma cells transfected with an active mutant form of sGC (sGCα1ß1(Cys105)) in athymic mice increased the survival time by 4-fold over the control. Histological analysis of xenografts overexpressing α1ß1(Cys105) sGC revealed changes in cellular architecture that resemble the morphology of normal cells. In addition, a decrease in angiogenesis contributed to glioma inhibition by sGC/cGMP therapy. Our study proposes the new concept that suppressed expression of sGC, a key enzyme in the NO/cGMP pathway, may be associated with an aggressive course of glioma. The sGC/cGMP signaling-targeted therapy may be a favorable alternative to chemotherapy and radiotherapy for glioma and perhaps other tumors.
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Antineoplásicos/metabolismo , Regulación Enzimológica de la Expresión Génica , Glioma/enzimología , Glioma/prevención & control , Guanilato Ciclasa/biosíntesis , Receptores Citoplasmáticos y Nucleares/biosíntesis , Animales , Antineoplásicos/farmacología , Línea Celular Tumoral , Glioma/patología , Guanilato Ciclasa/fisiología , Humanos , Ratones , Ratones Desnudos , Invasividad Neoplásica/patología , Invasividad Neoplásica/prevención & control , Receptores Citoplasmáticos y Nucleares/fisiología , Guanilil Ciclasa Soluble , Ensayos Antitumor por Modelo de Xenoinjerto/métodosRESUMEN
Polynuclear platinum compounds are more effective at killing glioblastoma cells than cisplatin, work by a different mechanism, and typically do not induce high levels of apoptosis at early time points after exposure. Here, we tested the hypothesis that combining BBR3610, the most potent polynuclear platinum, with a phosphoinositide-3-kinase (PI3K) inhibitor would promote apoptosis and enhance the impact on glioblastoma cells. The PI3K pathway is commonly activated in glioblastoma and promotes tumor cell survival, suggesting that its inhibition would make cells more sensitive to cytotoxic agents. We chose PX-866 as a PI3K inhibitor as it is a clinically promising agent being evaluated for brain tumor therapy. Combining BBR3610 and PX-866 resulted in synergistic killing of cultured glioma cells and an extension of survival in an orthotopic xenograft animal model. Both agents alone induced autophagy, and this appeared to be saturated, because when they were combined no additional autophagy was observed. However, the combination of PX-866 and BBR3610 did induce statistically significant increases in the level of apoptosis, associated with a reduction in pAkt and pBad, as well as inhibition of transwell migration. We conclude that combining polynuclear platinums with PI3K inhibitors has translational potential and alters the cellular response to include early apoptosis.
Asunto(s)
Neoplasias Encefálicas/tratamiento farmacológico , Glioma/tratamiento farmacológico , Gonanos/uso terapéutico , Compuestos Organoplatinos/uso terapéutico , Animales , Apoptosis/efectos de los fármacos , Autofagia/efectos de los fármacos , Western Blotting , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patología , Adhesión Celular/efectos de los fármacos , Ciclo Celular/efectos de los fármacos , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Sinergismo Farmacológico , Quimioterapia Combinada , Glioma/metabolismo , Glioma/patología , Humanos , Masculino , Ratones , Ratones Desnudos , Inhibidores de las Quinasa Fosfoinosítidos-3 , Proteínas Proto-Oncogénicas c-akt , ARN Mensajero/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal/efectos de los fármacos , Tasa de Supervivencia , Células Tumorales CultivadasRESUMEN
Male breast cancer (BCa) is a rare disease accounting for less than 1% of all breast cancers and 1% of all cancers in males. The clinical management is largely extrapolated from female BCa. Several multigene assays are increasingly used to guide clinical treatment decisions in female BCa, however, there are limited data on the utility of these tests in male BCa. Here we present the gene expression results of 381 M0, ER+ve, HER2-ve male BCa patients enrolled in the Part 1 (retrospective analysis) of the International Male Breast Cancer Program. Using a custom NanoString™ panel comprised of the genes from the commercial risk tests Prosigna®, OncotypeDX®, and MammaPrint®, risk scores and intrinsic subtyping data were generated to recapitulate the commercial tests as described by us previously. We also examined the prognostic value of other risk scores such as the Genomic Grade Index (GGI), IHC4-mRNA and our prognostic 95-gene signature. In this sample set of male BCa, we demonstrated prognostic utility on univariate analysis. Across all signatures, patients whose samples were identified as low-risk experienced better outcomes than intermediate-risk, with those classed as high risk experiencing the poorest outcomes. As seen with female BCa, the concordance between tests was poor, with C-index values ranging from 40.3% to 78.2% and Kappa values ranging from 0.17 to 0.58. To our knowledge, this is the largest study of male breast cancers assayed to generate risk scores of the current commercial and academic risk tests demonstrating comparable clinical utility to female BCa.
RESUMEN
Malignant gliomas are common primary tumors of the central nervous system. The prognosis of patients with malignant glioma is poor in spite of current intensive therapy and thus novel therapeutic modalities are necessary. Imatinib mesylate, a tyrosine kinase inhibitor, is effective in the therapy of tumors including leukemias but not as a monotherapy for malignant glioma. Recently, it is thought that the adequate modulation of autophagy can enhance efficacy of anticancer therapy. The outcome of autophagy manipulation, however, seems to depend on the autophagy initiator, the combined stimuli, the extent of cellular damage and the type of cells, and it is not yet fully understood how we should modulate autophagy to augment efficacy of each anticancer therapy. In this study, we examined the effect of imatinib with or without different types of autophagy inhibitors on human malignant glioma cells. Imatinib inhibited the viability of U87-MG and U373-MG cells in a dose dependent manner and caused nonapoptotic autophagic cell death. Suppression of imatinib-induced autophagy by 3-methyladenine or small interfering RNA against Atg5, which inhibit autophagy at an early stage, attenuated the imatinib-induced cytotoxicity. In contrast, inhibition of autophagy at a late stage by bafilomycin A1 or RTA 203 enhanced imatinib-induced cytotoxicity through the induction of apoptosis following mitochondrial disruption. Our findings suggest that therapeutic efficiency of imatinib for malignant glioma may be augmented by inhibition of autophagy at a late stage, and that appropriate modulation of autophagy may sensitize tumor cells to anticancer therapy.