Showing papers by "Carlos Cordon-Cardo published in 2011"

Distinct Expression Profiles of p63 Variants during Urothelial Development and Bladder Cancer Progression

Abstract: The TP63 gene, a member of the TP53 tumor suppressor gene family, can be expressed as at least six isoforms due to alternative promoter use and alternative splicing. The lack of p63 isoform–specific antibodies has limited the analysis of the biological significance of p63. We report a novel set of well-defined antibodies to examine p63 isoforms in mouse and human urothelium during embryogenesis and tumor progression, respectively. We provide evidence that basal and intermediate urothelial cells express p63 isoforms, with the TAp63 variant the first to be detected during development, whereas umbrella cells are characterized by a p63-negative phenotype. Notably, we report that p63-null mice develop a bladder with an abnormal urothelium, constituted by a single layer of cells that express uroplakin II and low molecular weight cytokeratins, consistent with an umbrella cell phenotype. Finally, analysis of 202 human bladder carcinomas revealed a new categorization of invasive tumors into basal-like (positive for ΔNp63 and high molecular weight cytokeratins and negative for low molecular weight cytokeratins) versus luminal-like (negative for ΔNp63 and high molecular weight cytokeratins and positive for low molecular weight cytokeratins) phenotypes, with ΔNp63 expression associated with an aggressive clinical course and poor prognosis. This study highlights the relevance of p63 isoforms in both urothelial development and bladder carcinoma progression, with ΔNp63 acting as an oncogene in certain invasive bladder tumors.

Disruption of a Sirt1 Dependent Autophagy Checkpoint in the Prostate Results in Prostatic Intraepithelial Neoplasia Lesion Formation

Abstract: The Sirtuin family of proteins (SIRTs) encode a group of evolutionarily conserved, NAD-dependent histone deacetylases, involved in many biological pathways. SIRT1, the human homolog of the yeast Silent Information Regulator 2 (Sir2) gene, deacetylates histones, p300, p53, and the androgen receptor. Autophagy is required for the degradation of damaged organelles and long-lived proteins, as well as for the development of glands such as the breast and prostate. Herein, homozygous deletion of the Sirt1 gene in mice resulted in prostatic intraepithelial neoplasia (PIN) associated with reduced autophagy. Genome-wide gene expression analysis of Sirt1-/- prostates demonstrated that endogenous Sirt1 repressed androgen responsive gene expression and induced autophagy in the prostate. Sirt1 induction of autophagy occurred at the level of autophagosome maturation and completion in cultured prostate cancer cells. These studies provide novel evidence for a checkpoint function of Sirt1 in the development of prostatic intraepithelial neoplasia and further highlight a role for SIRT1 as a tumor suppressor in the prostate.

Three-Dimensional Culture of Mouse Renal Carcinoma Cells in Agarose Macrobeads Selects for a Subpopulation of Cells with Cancer Stem Cell or Cancer Progenitor Properties

Abstract: The culture of tumor cell lines in three-dimensional scaffolds is considered to more closely replicate the in vivo tumor microenvironment than the standard method of two-dimensional cell culture. We hypothesized that our method of encapsulating and maintaining viable and functional pancreatic islets in agarose-agarose macrobeads (diameter 6-8 mm) might provide a novel method for the culture of tumor cell lines. In this report we describe and characterize tumor colonies that form within macrobeads seeded with mouse renal adenocarcinoma cells. Approximately 1% of seeded tumor cells survive in the macrobead and over several months form discrete elliptical colonies appearing as tumor cell niches with increasing metabolic activity in parallel to colony size. The tumor colonies demonstrate ongoing cell turnover as shown by BrdU incorporation and activated caspase-3 and TUNEL staining. Genes upregulated in the tumor colonies of the macrobead are likely adaptations to this novel environment, as well as an amplification of G(1)/S cell-cycle checkpoints. The data presented, including SCA-1 and Oct4 positivity and the upregulation of stem cell-like genes such as those associated with the Wnt pathway, support the notion that the macrobead selects for a subpopulation of cells with cancer stem cell or cancer progenitor properties.

KISS1 methylation and expression as tumor stratification biomarkers and clinical outcome prognosticators for bladder cancer patients.

Abstract: KISS1 is a metastasis suppressor gene that is lost in several malignancies, including bladder cancer. We tested the epigenetic silencing hypothesis and evaluated the biological influence of KISS1 methylation on its expression and clinical relevance in bladder cancer. KISS1 hypermethylation was frequent in bladder cancer cells analyzed by methylation-specific PCR and bisulfite sequencing and was associated with low gene expression, being restored in vitro by demethylating azacytidine. Hypermethylation was also frequently observed in a large series of bladder tumors (83.1%, n = 804). KISS1 methylation was associated with increasing stage (P = 0.001) and tumor grade (P = 0.010). KISS1 methylation was associated with low KISS1 transcript expression by quantitative RT-PCR (P = 0.037). KISS1 transcript expression was also associated with histopathological tumor stage (P < 0.0005). Low transcript expression alone (P = 0.003) or combined with methylation (P = 0.019) was associated with poor disease-specific survival (n = 205). KISS1 transcript expression remained an independent prognosticator in multivariate analyses (P = 0.017). KISS1 hypermethylation was identified in bladder cancer, providing a potential mechanistic explanation (epigenetic silencing) for the observed loss of KISS1 in uroepithelial malignancies. Associations of KISS1 methylation and its expression with histopathological variables and poor survival suggest the utility of incorporating KISS1 measurement using paraffin-embedded material for tumor stratification and clinical outcome prognosis of patients with uroepithelial neoplasias.

A Role for PML in Innate Immunity.

Abstract: The promyelocytic leukemia gene (PML) of acute promyelocytic leukemia is an established tumor suppressor gene with critical functions in growth suppression, induction of apoptosis, and cellular senescence. Interestingly, although less studied, PML seems to play a key role also in immune response to viral infection. Herein, we report that Pml-/-mice spontaneously develop an atypical invasive and lethal granulomatous lesion known as botryomycosis (BTM). In Pml-/-mice, BTM is the result of impaired function of macrophages, whereby they fail to become activated and are thus unable to clear pathogenic microorganisms. Accordingly, Pml-/-mice are resistant to lipopolysaccharide (LPS)-induced septic shock as a result of an ineffective production of cytokines and chemokines, suggesting a role for PML in the innate immune Toll-like receptor (TLR)/NF-κB prosurvival pathway. These results not only shed light on a new fundamental function of PML in innate immunity, but they also point to a proto-oncogenic role for PML in certain cellular and pathological contexts.

Hydrophilic Agarose Macrobead Cultures Select for Outgrowth of Carcinoma Cell Populations That Can Restrict Tumor Growth

Abstract: Cancer cells and their associated tumors have long been considered to exhibit unregulated proliferation or growth. However, a substantial body of evidence indicates that tumor growth is subject to both positive and negative regulatory controls. Here, we describe a novel property of tumor growth regulation that is neither species nor tumor-type specific. This property, functionally a type of feedback control, is triggered by the encapsulation of neoplastic cells in a growth-restricting hydrogel composed of an agarose matrix with a second coating of agarose to form 6- to 8-mm diameter macrobeads. In a mouse cell model of renal adenocarcinoma (RENCA cells), this process resulted in selection for a stem cell-like subpopulation which together with at least one other cell subpopulation drove colony formation in the macrobeads. Cells in these colonies produced diffusible substances that markedly inhibited in vitro and in vivo proliferation of epithelial-derived tumor cells outside the macrobeads. RENCA cells in monolayer culture that were exposed to RENCA macrobead-conditioned media exhibited cell-cycle accumulation in S phase due to activation of a G(2)/M checkpoint. At least 10 proteins with known tumor suppression functions were identified by analysis of RENCA macrobead-conditioned media, the properties of which offer opportunities to further dissect the molecular basis for tumor growth control. More generally, macrobead culture may permit the isolation of cancer stem cells and other cells of the stem cell niche, perhaps providing strategies to define more effective biologically based clinical approaches to treat neoplastic disease.

Alternate PAX3 and PAX7 C-terminal isoforms in myogenic differentiation and sarcomagenesis.

Abstract: Pax3 and Pax7 are closely related genes that are involved in commitment of cells to a myogenic lineage during skeletal muscle development and regeneration. Several Pax3 and Pax7 transcripts are expressed from the genes, generating different isoforms with potentially distinct DNA binding and transactivation properties. The aim of this study was to investigate the implication of Pax3 and Pax7 C-terminal isoforms during myogenic differentiation and tumorigenesis, since fusions involving these genes are commonly associated with alveolar rhabdomyosarcoma (ARMS). Uncommitted (mouse mesenchymal stem cells, MSCs) and committed (C2C12) myogenic precursor cells were stably transfected with PAX3/FKHR and PAXC7/FKHR fusion genes. We analysed gene and protein expression comparing the newly generated cells with the parental cells, to determine the functional importance of Pax3 and Pax7 C-terminal isoforms. We found that the transcript Pax3c was expressed at low levels in undifferentiated C2C12 and MSCs cells, but its expression levels increased considerably at later stages of differentiation. However, expression levels of Pax3d transcript increased only slightly after differentiation. Pax7 transcripts, present before differentiation in committed C2C12 cells, but absent in uncommitted MSCs, increased noticeably in MSCs after differentiation. We also found that the presence of PAX/FKHR fusions prevented both C2C12 and MSC cells from terminal myogenic differentiation and increased the expression of discrete endogenous Pax3/7 transcripts, in particular Pax3d and Pax7B. Conclusions Our results suggest that both Pax3 and Pax7 transcripts are required for commitment of cells to the myogenic lineage, with each transcript having a distinct role. More specifically, the Pax3c isoform may be required for terminal myogenic differentiation whereas the Pax3d isoform may be involved in undifferentiated cell maintenance and/or proliferation.

Abstract 2405: Identification of PHLPP as a tumour suppressor reveals the role of pathway feedback compensation in PTEN-mutant prostate cancer progression

Abstract: Hyper-activation of the PI 3-Kinase/ AKT pathway is common in many cancer types. Tumourigenesis through this pathway is prevented by concerted action of multiple tumour suppressor genes. Most notably, PTEN reverts PI 3-Kinase activity whereas excessive pathway activation triggers the p53-mediated senescence arrest. However, it remains ill defined if and at what stage this response acts in human prostate cancer. Here we identify the AKT-inactivating phosphatase PHLPP as a tumour suppressor and demonstrate how the p53-response can antagonise co-deletion of PTEN and PHLPP to form a barrier against prostate cancer progression. We show that Phlpp-loss causes neoplasia and upon partial Pten-loss, carcinoma in mouse prostate. In this setting, Phlpp-deficiency triggers growth arrest via mTorC1-dependent activation of p53 and we find that co-deletion of Pten and Phlpp selects for spontaneous inactivation of p53 in prostate. Validating this conditional gene inactivation scheme in a comprehensive genomic patient data set we find that co-deletion of PTEN and PHLPP is almost exclusively observed in metastatic prostate cancer and tightly correlated to deletion of TP53. Furthermore, PTEN/ PHLPP expression can be used to predict disease outcome in these patients, comparable to the standard histology based method, but adding actionable information on pathway status. Finally, we show that both known PHLPP isoforms compensate for PTEN-suppression in a novel pathway feedback explaining their co-deletion with PTEN in the metastatic samples. Surprisingly, we find that the feedback surge of these genes is sensitive to some pharmacological inhibitors of the PI 3-Kinase pathway. Collectively, our findings emphasise the need for careful evaluation of PI 3-Kinase target therapy effects in prostate cancer and highlight the value of genetically engineered mouse models in this process. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2405. doi:10.1158/1538-7445.AM2011-2405

Enfoque personalizado para el pronóstico del cáncer de próstata.

Abstract: La medicina personalizada en el manejo de pacientes con cancer de prostata consiste en la integracion de las caracteristicas del paciente, tales como la edad, el riesgo genetico y comorbilidades con variables clinico-patologicas especificas, incluyendo el antigeno prostatico especifico (PSA), imagenes y caracteristicas del diagnostico de la biopsia de aguja o del especimen de prostatectomia, incluyendo la diferenciacion del tumor (es decir, Gleason), el volumen y extension de la enfermedad (longitud del tumor y/o el porcentaje, numero de cilindros positivos en el diagnostico o el estadio patologico post-cirugia, incluyendo el estado de los margenes). Aunque el desarrollo de diversos instrumentos estadisticos clinicos, tales como los nomogramas han proporcionado un mecanismo para explorar estas variables, la mayoria de los urologos se basan en las caracteristicas basicas de pronostico de la etapa, grado y PSA junto con el juicio clinico para definir y comprender el riesgo individual y predecir los resultados. Ademas, a diferencia de otros tipos de tumores como el cancer de mama, no existen estudios auxiliares de diagnostico de rutina realizados en la biopsia prostatica o la pieza de prostatectomia para apoyar y perfeccionar el proceso de decision sobre el tratamiento para cada paciente individual. En esta revision proporcionaremos un resumen de la practica actual de modelos predictivos en el cancer de prostata y exploraremos como los avances tecnicos en la histologia funcional han desempenado un papel en el desarrollo y la incorporacion de una plataforma de sistemas para la provision de un perfil de riesgo especifico para cada paciente util para la toma de decisiones clinicas.

Reversal of glucocorticoid resistance by the g-secretase inhibitor PF-03084014 in T-cell acute lymphoblastic leukemia.

Abstract: 9553 Background: T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic cancer frequently characterized by activating mutations in NOTCH1. Early studies identified NOTCH1 as an attractive therapeutic target for the treatment of T-ALL through the use of g-secretase inhibitors (GSIs), but subsequent work found that inhibition of NOTCH signaling is characterized by a lack of cytotoxicity of human T-ALL cells and severe gastrointestinal toxicity. Our preliminary results show that combination therapy of generic GSIs plus glucocorticoids has improved antileukemic effects in vitro and in vivo and reduced gut toxicity. Here we characterized the interaction between PF-03084014, a clinically relevant GSI, and dexamethasone in preclinical models of glucocorticoid resistant T-ALL. Methods: Studies were performed using a panel of human T-ALL cell lines and primary patient samples. The effect of GSI treatment plus glucocorticoids was assessed using cell viability, cell cycle, and proliferation assays....

Corrigendum: Pharmacologic inactivation of kinase suppressor of ras-1 abrogates Ras-mediated pancreatic cancer

Abstract: Corrigendum: Pharmacologic inactivation of kinase suppressor of ras-1 abrogates Ras-mediated pancreatic cancer