RESUMEN
The tumor suppressor gene PTEN is the second most commonly deleted gene in cancer. Such deletions often include portions of the chromosome 10q23 locus beyond the bounds of PTEN itself, which frequently disrupts adjacent genes. Coincidental loss of PTEN-adjacent genes might impose vulnerabilities that could either affect patient outcome basally or be exploited therapeutically. Here, we describe how the loss of ATAD1, which is adjacent to and frequently co-deleted with PTEN, predisposes cancer cells to apoptosis triggered by proteasome dysfunction and correlates with improved survival in cancer patients. ATAD1 directly and specifically extracts the pro-apoptotic protein BIM from mitochondria to inactivate it. Cultured cells and mouse xenografts lacking ATAD1 are hypersensitive to clinically used proteasome inhibitors, which activate BIM and trigger apoptosis. This work furthers our understanding of mitochondrial protein homeostasis and could lead to new therapeutic options for the hundreds of thousands of cancer patients who have tumors with chromosome 10q23 deletion.
Cancer cells have often lost genetic sequences that control when and how cell division takes place. Deleting these genes, however, is not an exact art, and neighboring sequences regularly get removed in the process. For example, the loss of the tumor suppressor gene PTEN, the second most deleted gene in cancer, frequently involves the removal of the nearby ATAD1 gene. While hundreds of thousands of human tumors completely lack ATAD1, individuals born without a functional version of this gene do not survive past early childhood. How can tumor cells cope without ATAD1 and could these coping strategies become the target for new therapies? Winter et al. aimed to answer these questions by examining a variety of cancer cells lacking ATAD1 in the laboratory. Under normal circumstances, the enzyme that this gene codes for sits at the surface of mitochondria, the cellular compartments essential for energy production. There, it extracts any faulty, defective proteins that may otherwise cause havoc and endanger mitochondrial health. Experiments revealed that without ATAD1, cancer cells started to rely more heavily on an alternative mechanism to remove harmful proteins: the process centers on MARCH5, an enzyme which tags molecules that require removal so the cell can recycle them. Drugs that block the pathway involving MARCH5 already exist, but they have so far been employed to treat other types of tumors. Winter et al. showed that using these compounds led to the death of cancerous ATAD1-deficient cells, including in human tumors grown in mice. Overall, this work demonstrates that cancer cells which have lost ATAD1 become more vulnerable to disruptions in the protein removal pathway mediated by MARCH5, including via already existing drugs. If confirmed by further translational work, these findings could have important clinical impact given how frequently PTEN and ATAD1 are lost together in cancer.
Asunto(s)
Neoplasias , Complejo de la Endopetidasa Proteasomal , Humanos , Animales , Ratones , Complejo de la Endopetidasa Proteasomal/metabolismo , ATPasas Asociadas con Actividades Celulares Diversas/genética , ATPasas Asociadas con Actividades Celulares Diversas/metabolismo , Fosfohidrolasa PTEN/metabolismo , Mitocondrias/metabolismo , Neoplasias/genéticaRESUMEN
Clear cell renal cell carcinoma (ccRCC), the most common form of kidney cancer, is typically initiated by inactivation of the von Hippel Lindau (VHL) gene, which results in the constitutive activation of the hypoxia inducible factors, HIF-1α and HIF-2α. Using a high throughput screen, we identify novel compounds that decrease HIF-1/2α levels and induce ferroptosis by targeting Iron Sulfur Cluster Assembly 2 (ISCA2), a component of the late mitochondrial Iron Sulfur Cluster (L-ISC) assembly complex. ISCA2 inhibition either pharmacologically or using siRNA decreases HIF-2α protein levels by blocking iron-responsive element (IRE)-dependent translation, and at higher concentrations, also decreases HIF-1α translation through unknown mechanisms. Additionally, ISCA2 inhibition triggers the iron starvation response, resulting in iron/metals overload and death via ferroptosis. ISCA2 levels are decreased in ccRCC compared to normal kidney, and decreased ISCA2 levels are associated with pVHL loss and with sensitivity to ferroptosis induced by ISCA2 inhibition. Strikingly, pharmacological inhibition of ISCA2 using an orally available ISCA2 inhibitor significantly reduced ccRCC xenograft growth in vivo, decreased HIF-α levels and increased lipid peroxidation, suggesting increased ferroptosis in vivo. Thus, the targeting of ISCA2 may be a promising therapeutic strategy to inhibit HIF-1/2α and to induce ferroptosis in pVHL deficient cells.
Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Carcinoma de Células Renales , Ferroptosis , Proteínas Hierro-Azufre , Neoplasias Renales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Carcinoma de Células Renales/tratamiento farmacológico , Carcinoma de Células Renales/genética , Carcinoma de Células Renales/metabolismo , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Proteínas Hierro-Azufre/genética , Proteínas Hierro-Azufre/metabolismo , Neoplasias Renales/tratamiento farmacológico , Neoplasias Renales/genética , Neoplasias Renales/metabolismo , ARN Interferente Pequeño , Proteína Supresora de Tumores del Síndrome de Von Hippel-Lindau/genética , Proteína Supresora de Tumores del Síndrome de Von Hippel-Lindau/metabolismoRESUMEN
PURPOSE: Clear cell renal cell carcinoma (ccRCC) is frequently associated with inactivation of the von Hippel-Lindau tumor suppressor, resulting in activation of HIF-1α and HIF-2α. The current paradigm, established using mechanistic cell-based studies, supports a tumor promoting role for HIF-2α, and a tumor suppressor role for HIF-1α. However, few studies have comprehensively examined the clinical relevance of this paradigm. Furthermore, the hypoxia-associated factor (HAF), which regulates the HIFs, has not been comprehensively evaluated in ccRCC. EXPERIMENTAL DESIGN: To assess the involvement of HAF/HIFs in ccRCC, we analyzed their relationship to tumor grade/stage/outcome using tissue from 380 patients, and validated these associations using tissue from 72 additional patients and a further 57 patients treated with antiangiogenic therapy for associations with response. Further characterization was performed using single-cell mRNA sequencing (scRNA-seq), RNA-in situ hybridization (RNA-ISH), and IHC. RESULTS: HIF-1α was primarily expressed in tumor-associated macrophages (TAMs), whereas HIF-2α and HAF were expressed primarily in tumor cells. TAM-associated HIF-1α was significantly associated with high tumor grade and increased metastasis and was independently associated with decreased overall survival. Furthermore, elevated TAM HIF-1α was significantly associated with resistance to antiangiogenic therapy. In contrast, high HAF or HIF-2α were associated with low grade, decreased metastasis, and increased overall survival. scRNA-seq, RNA-ISH, and Western blotting confirmed the expression of HIF-1α in M2-polarized CD163-expressing TAMs. CONCLUSIONS: These findings highlight a potential role of TAM HIF-1α in ccRCC progression and support the reevaluation of HIF-1α as a therapeutic target and marker of disease progression.
Asunto(s)
Biomarcadores de Tumor/metabolismo , Carcinoma de Células Renales/mortalidad , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Neoplasias Renales/mortalidad , Macrófagos Asociados a Tumores/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/análisis , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Biomarcadores de Tumor/análisis , Carcinoma de Células Renales/diagnóstico , Carcinoma de Células Renales/genética , Carcinoma de Células Renales/terapia , Línea Celular Tumoral , Quimioterapia Adyuvante , Progresión de la Enfermedad , Femenino , Regulación Neoplásica de la Expresión Génica , Genes Supresores de Tumor , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/análisis , Neoplasias Renales/diagnóstico , Neoplasias Renales/genética , Neoplasias Renales/terapia , Masculino , Persona de Mediana Edad , Clasificación del Tumor , Estadificación de Neoplasias , Nefrectomía , Pronóstico , RNA-Seq , Estudios Retrospectivos , Análisis de la Célula Individual , Análisis de Supervivencia , Macrófagos Asociados a Tumores/inmunologíaAsunto(s)
Leucemia Mieloide/genética , Mutación , Trastornos Mieloproliferativos/genética , Proteína p53 Supresora de Tumor/genética , Enfermedad Aguda , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Inmunohistoquímica/métodos , Leucemia Mieloide/diagnóstico , Leucemia Mieloide/metabolismo , Masculino , Persona de Mediana Edad , Trastornos Mieloproliferativos/diagnóstico , Trastornos Mieloproliferativos/metabolismo , Coloración y Etiquetado/métodos , Proteína p53 Supresora de Tumor/biosíntesis , Adulto JovenRESUMEN
Recurrent heterozygous mutation of isocitrate dehydrogenase 1 gene (IDH1), predominantly resulting in histidine substitution at arginine 132, was first identified in glioma. The biological significance of IDH1R132H, however, has been controversial, and its prevalent association with glioma remains enigmatic. Although recent studies indicate that IDH1R132H is nonessential to tumor growth or even anti-tumor growth, whether IDH1R132H initiates gliomagenesis remains obscure. In this study, we report that IDH1R132H is intrinsically tumor-suppressive but the activity can be attenuated by glutamate-the cerebral neurotransmitter. We observed that IDH1R132H was highly suppressive of subcutaneous tumor growth driven by platelet-derived growth factor B (PDGFB), but IDH1R132H tumor growth and glioma penetrance were virtually indistinguishable from those of IDH1-wildtype tumors in orthotopic models. In vitro, addition of glutamate compromised IDH1R132H inhibition of neurosphere genesis, indicating glutamate promotion of oncogenic dominance. Furthermore, we observed that IDH1R132H expression was markedly decreased in tumors but became more permissible upon the deletion of tumor-suppressor gene Cdkn2a. To provide direct evidence for the opposing effect of IDH1R132H on PDGFB-driven glioma development, we explored tandem expression of the two molecules from a single transcript to preclude selection against IDH1R132H expression. Our results demonstrate that when juxtaposed with oncogenic PDGFB, IDH1R132H overrides the oncogenic activity and obliterates neurosphere genesis and gliomagenesis even in the glutamate-rich microenvironment. We propose therefore that IDH1R132H is intrinsically suppressive of glioma initiation and growth but such tumor-suppressive activity is compromised by the glutamate-rich cerebral cortex, thereby offering a unifying hypothesis for the perplexing role of IDH1R132H in glioma initiation and growth.
RESUMEN
Isocitrate dehydrogenase 1 (IDH1) is the most commonly mutated gene in grade II-III glioma and secondary glioblastoma (GBM). A causal role for IDH1R132H in gliomagenesis has been proposed, but functional validation in vivo has not been demonstrated. In this study, we assessed the role of IDH1R132H in glioma development in the context of clinically relevant cooperating genetic alterations in vitro and in vivo. Immortal astrocytes expressing IDH1R132H exhibited elevated (R)-2-hydroxyglutarate levels, reduced NADPH, increased proliferation, and anchorage-independent growth. Although not sufficient on its own, IDH1R132H cooperated with PDGFA and loss of Cdkn2a, Atrx, and Pten to promote glioma development in vivo. These tumors resembled proneural human mutant IDH1 GBM genetically, histologically, and functionally. Our findings support the hypothesis that IDH1R132H promotes glioma development. This model enhances our understanding of the biology of IDH1R132H-driven gliomas and facilitates testing of therapeutic strategies designed to combat this deadly disease.
Asunto(s)
Astrocitos/enzimología , Carcinogénesis/metabolismo , Glioma/enzimología , Isocitrato Deshidrogenasa/metabolismo , Mutación Missense , Proteínas de Neoplasias/metabolismo , Sustitución de Aminoácidos , Animales , Astrocitos/patología , Carcinogénesis/genética , Carcinogénesis/patología , Glioma/genética , Glioma/patología , Humanos , Isocitrato Deshidrogenasa/genética , Ratones , Ratones Transgénicos , Proteínas de Neoplasias/genéticaRESUMEN
We demonstrate that SCF-KIT signaling induces synthesis and secretion of endothelin-3 (ET3) in human umbilical vein endothelial cells and melanoma cells in vitro, gastrointestinal stromal tumors, human sun-exposed skin, and myenteric plexus of human colon post-fasting in vivo. This is the first report of a physiological mechanism of ET3 induction. Integrating our finding with supporting data from literature leads us to discover a previously unreported pathway of nitric oxide (NO) generation derived from physiological endothelial NO synthase (eNOS) or neuronal NOS (nNOS) activation (referred to as the KIT-ET3-NO pathway). It involves: (1) SCF-expressing cells communicate with neighboring KIT-expressing cells directly or indirectly (cleaved soluble SCF). (2) SCF-KIT signaling induces timely local ET3 synthesis and secretion. (3) ET3 binds to ETBR on both sides of intercellular space. (4) ET3-binding-initiated-ETBR activation increases cytosolic Ca2+, activates cell-specific eNOS or nNOS. (5) Temporally- and spatially-precise NO generation. NO diffuses into neighboring cells, thus acts in both SCF- and KIT-expressing cells. (6) NO modulates diverse cell-specific functions by NO/cGMP pathway, controlling transcriptional factors, or other mechanisms. We demonstrate the critical physiological role of the KIT-ET3-NO pathway in fulfilling high demand (exceeding basal level) of endothelium-dependent NO generation for coping with atherosclerosis, pregnancy, and aging. The KIT-ET3-NO pathway most likely also play critical roles in other cell functions that involve dual requirement of SCF-KIT signaling and NO. New strategies (e.g. enhancing the KIT-ET3-NO pathway) to harness the benefit of endogenous eNOS and nNOS activation and precise NO generation for correcting pathophysiology and restoring functions warrant investigation.
Asunto(s)
Endotelina-3/metabolismo , Óxido Nítrico/metabolismo , Proteínas Proto-Oncogénicas c-kit/metabolismo , Receptor de Endotelina B/metabolismo , Factor de Células Madre/metabolismo , Aterosclerosis/patología , Línea Celular Tumoral , Endotelio Vascular/metabolismo , Ensayo de Inmunoadsorción Enzimática , Motilidad Gastrointestinal , Tumores del Estroma Gastrointestinal/metabolismo , Tumores del Estroma Gastrointestinal/patología , Tumores del Estroma Gastrointestinal/fisiopatología , Homeostasis , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Inmunohistoquímica , Melanoma/patología , Plexo Mientérico/metabolismo , Invasividad Neoplásica , Óxido Nítrico Sintasa de Tipo I/metabolismo , Óxido Nítrico Sintasa de Tipo III/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos , Transducción de Señal , Piel/metabolismo , Luz Solar , Factores de Tiempo , Regulación hacia Arriba/genética , VasodilataciónRESUMEN
INTRODUCTION: The most widely used methods for determination of HER2/neu status in breast carcinoma are immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). Both techniques are associated with technical and interpretive difficulties. Alternative methods exist including quantitative PCR and the newly developed chromogenic dual in situ hybridization (DISH). METHODS: We evaluated HER2 DISH as an alternative to FISH and report our findings from 101 cases. In addition, we correlated HER2 DISH and FISH results with HercepTest and 4B5 immunohistochemistry. RESULTS: Eight cases failed FISH analysis and none failed DISH analysis. A 95% (88/93) concordance was found between DISH and FISH for all cases in the series. When only 2+ IHC cases were evaluated, the concordance was 94% for DISH and FISH. Using the 2013 ASCO/CAP recommendations, none of the tested cases were equivocal by FISH or DISH despite 66% of cases being 2+ by HercepTest and 32% by the 4B5 antibody. COMMENT: Our study, which utilizes a majority of IHC equivocal cases, demonstrates that HER2 FISH and DISH are concordant methodologies. HER2 DISH is therefore an acceptable alternative to FISH.
Asunto(s)
Neoplasias de la Mama/diagnóstico , Hibridación Fluorescente in Situ/métodos , Neoplasias de la Mama/patología , Estudios de Factibilidad , Femenino , Humanos , Inmunohistoquímica , Receptor ErbB-2/metabolismo , Reproducibilidad de los ResultadosRESUMEN
BACKGROUND: The Provirus integrating site Moloney murine leukemia virus (Pim) family are proteins with serine/threonine kinase activity. Studies have demonstrated overexpression of Pims in cancer. To our knowledge, only a single study has examined Pim-1 in urothelial carcinoma. The aim of this investigation was to evaluate Pim-1, Pim-2, and Pim-3 in urothelial carcinoma and assess for expression that may contribute to disease progression and serve as a site for targeted therapy. METHODS: This retrospective study included 137 cases taken from specimens from the University of Utah, Department of Pathology (2008 to 2011). Tissue was stained with antibodies against Pim-1, Pim-2, and Pim-3. Cases were classified into 3 groups, based upon current World Health Organization criteria (invasive high-grade urothelial carcinoma [IHG] [n=84], noninvasive high-grade urothelial carcinoma/carcinoma in situ [n=32], and noninvasive low-grade urothelial carcinoma [NILG] [n=21]). Cases were scored and recorded as positive or negative on the basis of the percentage of cells with cytoplasmic and/or nuclear staining. RESULTS: NILG showed higher expression of Pim-1 (relative expression rate [RER]=2.28; 95% confidence interval [CI], 0.183-0.764) and Pim-3 (RER=3.06; 95% CI, 0.423-0.816) compared with other lesions. IHG had lower expression of Pim-1 (RER=0.31; 95% CI, 0.401-0.844) and Pim-3 (RER=0.354; 95% CI, 0.322-0.816) and noninvasive high-grade urothelial carcinoma (NIHG) demonstrated increased expression of Pim-1 and (RER=2.09; 95% CI, 0.124-0.739) and Pim-2 (RER=1.70; 95% CI, 0.151-0.591). At least 1 Pim kinase protein was expressed at the following rates: 49% in IHG, 66% in NIHG, and 76% in NILG. CONCLUSION: A high percentage of urothelial carcinomas express Pim kinases. Pim expression differs in NILG, NIHG, and IHG lesions.
Asunto(s)
Regulación Enzimológica de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Proteínas Proto-Oncogénicas c-pim-1/biosíntesis , Neoplasias Urológicas , Urotelio , Femenino , Humanos , Masculino , Neoplasias Urológicas/enzimología , Neoplasias Urológicas/patología , Urotelio/enzimología , Urotelio/patologíaRESUMEN
OBJECTIVES: Based on previous molecular studies, a small fraction of primary mediastinal (thymic) large B-cell lymphoma (PMBL) demonstrates MYC alterations. However, no studies have evaluated MYC protein expression by immunohistochemistry (IHC) with follow-up fluorescence in situ hybridization (FISH) analysis. We aim to evaluate the clinicopathologic importance of MYC IHC expression in PMBL. METHODS: Three pathologists independently evaluated MYC IHC expression in 32 cases of PMBL for percent tumor positivity and nuclear intensity. FISH analysis for MYC rearrangement was performed on cases with high MYC IHC expression. Clinical data including treatment, follow-up, and outcome were also reviewed in a subset of cases. RESULTS: Variable MYC protein expression by IHC was detected in 30 (94%) of 32 cases of PMBL. One-third of the positive cases (10/30) showed high MYC IHC expression of at least 30% nuclear positivity. FISH analyses for MYC rearrangement on these 10 cases were negative. Review of clinical data on a subset of cases with high and low MYC IHC expression showed no differences in clinical outcome. CONCLUSIONS: MYC protein expression by IHC is present in most PMBLs. Increased MYC protein expression can be seen in one-third of the cases; however, it does not correlate with genetic abnormalities by FISH. There is also no significant impact of MYC protein expression on clinical outcomes.
Asunto(s)
Biomarcadores de Tumor/metabolismo , Linfoma de Células B/metabolismo , Neoplasias del Mediastino/metabolismo , Proteínas Proto-Oncogénicas c-myc/metabolismo , Adolescente , Adulto , Anciano , Femenino , Humanos , Inmunohistoquímica , Hibridación Fluorescente in Situ , Linfoma de Células B/patología , Masculino , Neoplasias del Mediastino/patología , Persona de Mediana Edad , Adulto JovenRESUMEN
The proto-oncogene proviral integration site for moloney murine leukemia virus (PIM) kinases (PIM-1, PIM-2, and PIM-3) are serine/threonine kinases that are involved in a number of signaling pathways important to cancer cells. PIM kinases act in downstream effector functions as inhibitors of apoptosis and as positive regulators of G1-S phase progression through the cell cycle. PIM kinases are upregulated in multiple cancer indications, including lymphoma, leukemia, multiple myeloma, and prostate, gastric, and head and neck cancers. Overexpression of one or more PIM family members in patient tumors frequently correlates with poor prognosis. The aim of this investigation was to evaluate PIM expression in low- and high-grade urothelial carcinoma and to assess the role PIM function in disease progression and their potential to serve as molecular targets for therapy. One hundred thirty-seven cases of urothelial carcinoma were included in this study of surgical biopsy and resection specimens. High levels of expression of all three PIM family members were observed in both noninvasive and invasive urothelial carcinomas. The second-generation PIM inhibitor, TP-3654, displays submicromolar activity in pharmacodynamic biomarker modulation, cell proliferation studies, and colony formation assays using the UM-UC-3 bladder cancer cell line. TP-3654 displays favorable human ether-à-go-go-related gene and cytochrome P450 inhibition profiles compared with the first-generation PIM inhibitor, SGI-1776, and exhibits oral bioavailability. In vivo xenograft studies using a bladder cancer cell line show that PIM kinase inhibition can reduce tumor growth, suggesting that PIM kinase inhibitors may be active in human urothelial carcinomas.
Asunto(s)
Antineoplásicos/farmacología , Carcinoma de Células Transicionales/enzimología , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas c-pim-1/antagonistas & inhibidores , Neoplasias de la Vejiga Urinaria/enzimología , Animales , Western Blotting , Femenino , Humanos , Imidazoles/farmacología , Masculino , Ratones , Ratones Desnudos , Reacción en Cadena de la Polimerasa Multiplex , Oligopéptidos/farmacología , Proto-Oncogenes Mas , Piridazinas/farmacología , ARN Interferente Pequeño , Ratas , Ratas Sprague-Dawley , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción Genética , Péptido Intestinal Vasoactivo/farmacología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Merkel cell carcinoma is a highly aggressive cutaneous neuroendocrine tumor that has been associated with Merkel cell polyomavirus in up to 80% of cases. Merkel cell polyomavirus is believed to influence pathogenesis, at least in part, through expression of the large T antigen, which includes a retinoblastoma protein-binding domain. However, there appears to be significant clinical and morphological overlap between polyomavirus-positive and polyomavirus-negative Merkel cell carcinoma cases. Although much of the recent focus of Merkel cell carcinoma pathogenesis has been on polyomavirus, the pathogenesis of polyomavirus-negative cases is still poorly understood. We hypothesized that there are underlying human somatic mutations that unify Merkel cell carcinoma pathogenesis across polyomavirus status, and to investigate we performed whole exome sequencing on five polyomavirus-positive cases and three polyomavirus-negative cases. We found that there were no significant differences in the overall number of single-nucleotide variations, copy number variations, insertion/deletions, and chromosomal rearrangements when comparing polyomavirus-positive to polyomavirus-negative cases. However, we did find that the retinoblastoma pathway genes harbored a high number of mutations in Merkel cell carcinoma. Furthermore, the retinoblastoma gene (RB1) was found to have nonsense truncating protein mutations in all three polyomavirus-negative cases; no such mutations were found in the polyomavirus-positive cases. In all eight cases, the retinoblastoma pathway dysregulation was confirmed by immunohistochemistry. Although polyomavirus-positive Merkel cell carcinoma is believed to undergo retinoblastoma dysregulation through viral large T antigen expression, our findings demonstrate that somatic mutations in polyomavirus-negative Merkel cell carcinoma lead to retinoblastoma dysregulation through an alternative pathway. This novel finding suggests that the retinoblastoma pathway dysregulation leads to an overlapping Merkel cell carcinoma phenotype and that oncogenesis occurs through either a polyomavirus-dependent (viral large T antigen expression) or polyomavirus-independent (host somatic mutation) mechanism.
Asunto(s)
Biomarcadores de Tumor/genética , Carcinoma de Células de Merkel/genética , Análisis Mutacional de ADN/métodos , Exoma , Genes de Retinoblastoma , Mutación , Infecciones por Polyomavirus/genética , Proteína de Retinoblastoma/genética , Neoplasias Cutáneas/genética , Infecciones Tumorales por Virus/genética , Anciano , Anciano de 80 o más Años , Biomarcadores de Tumor/análisis , Carcinoma de Células de Merkel/química , Carcinoma de Células de Merkel/virología , Femenino , Predisposición Genética a la Enfermedad , Humanos , Inmunohistoquímica , Masculino , Poliomavirus de Células de Merkel/aislamiento & purificación , Persona de Mediana Edad , Fenotipo , Infecciones por Polyomavirus/metabolismo , Infecciones por Polyomavirus/virología , Proteína de Retinoblastoma/análisis , Neoplasias Cutáneas/química , Neoplasias Cutáneas/virología , Infecciones Tumorales por Virus/metabolismo , Infecciones Tumorales por Virus/virologíaRESUMEN
The accurate diagnosis of a juvenile granulosa cell tumor (JGCT) can be challenging, as these neoplasms often exhibit morphologic features that overlap other ovarian neoplasms. In addition, the immunohistochemical profile exhibited by JGCT is fairly nonspecific and typically includes reactivity for CD99. Recently, we noted that JGCTs can show immunohistochemical expression of Fli-1, a transcription factor expressed by Ewing sarcoma, a neoplasm that is occasionally in the differential diagnosis of JGCT. We evaluated a series of JGCTs to determine whether Fli-1 is commonly expressed by these tumors and whether they demonstrate chromosomal arrangements in EWSR1. Cases diagnosed as JGCT (n=11) were immunohistochemically evaluated for expression of Fli-1 and CD99. Fluorescence in situ hybridization was performed on all cases to search for chromosomal rearrangements in EWSR1. All 11 of our cases exhibited positive immunohistochemical staining for Fli-1 and CD99. None of the cases demonstrated rearrangement in EWSR1 by fluorescence in situ hybridization. In cases of JGCT that cannot be reliably distinguished from Ewing sarcoma based on morphology and immunohistochemistry alone, fluorescence in situ hybridization testing for EWSR1 rearrangements seems to be a useful diagnostic adjunct for their separation.
Asunto(s)
Biomarcadores de Tumor/análisis , Tumor de Células de la Granulosa/genética , Tumor de Células de la Granulosa/metabolismo , Neoplasias Ováricas/genética , Neoplasias Ováricas/metabolismo , Antígeno 12E7 , Antígenos CD/biosíntesis , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Proteínas de Unión a Calmodulina/genética , Moléculas de Adhesión Celular/biosíntesis , Niño , Femenino , Humanos , Inmunohistoquímica , Hibridación Fluorescente in Situ , Proteínas de Microfilamentos/biosíntesis , Proteína EWS de Unión a ARN , Proteínas de Unión al ARN/genética , Receptores Citoplasmáticos y Nucleares/biosíntesis , Transactivadores , Translocación GenéticaRESUMEN
The ability to characterize distribution of neoplastic hematopoietic cells and their progenitors in their native microenvironment is emerging as an important challenge and potential therapeutic target in many disease areas, including multiple myeloma. In multiple myeloma, bone marrow (BM) angiogenesis is typically increased and microvessel density is a known indicator of poor prognosis. However, the difficulty of consistently measuring 3D vessels from 2D cut sections has previously limited the study of spatial distribution of plasma cells (PC) and their interaction with BM microenvironment. The aim of the study is to report a novel method to study myeloma cells spatial distribution within their hematopoietic niche context using readily available tissue sections and standard histology approaches. We utilized a novel whole-tissue image analysis approach to identify vessels, and then applied computational grown regions extended out from each vessel at 15, 35, 55, 75, and 100 µm to identify the spatial distribution of PC on CD34/CD138 double-stained core biopsy slides. Percent PC to total cells (TC) was significantly higher at <15 µm distance compared with those at 16 to 35, 36 to 55, 56 to 75, and 76 to 100 µm distance (P=0.0001). Similarly, PC/TC at <35 µm region was significantly higher compared with 36 to 55 (P=0.0001), 56 to 75 (P≤0.0001), and 76 to 100 (P=0.0002) µm distances. The mean PC/TC differences in the spatial gradient of 36 to 55, 56 to 75, and 76 to 100 µm distance regions were not significant. Our findings suggest possible preferential advantage to neoplastic PC in the proximity of blood vessels compared with other hematopoietic marrow cells. We demonstrate the feasibility of analyzing the spatial distribution of PC, and possibly other hematopoietic/stem cells in their microenvironment, as characterized by the distance to vessels in BM using a novel image analysis approach.
Asunto(s)
Células de la Médula Ósea , Médula Ósea , Procesamiento de Imagen Asistido por Computador/métodos , Mieloma Múltiple , Células Plasmáticas , Adulto , Anciano , Antígenos CD34/biosíntesis , Médula Ósea/irrigación sanguínea , Médula Ósea/metabolismo , Médula Ósea/patología , Células de la Médula Ósea/metabolismo , Células de la Médula Ósea/patología , Humanos , Procesamiento de Imagen Asistido por Computador/instrumentación , Masculino , Persona de Mediana Edad , Mieloma Múltiple/irrigación sanguínea , Mieloma Múltiple/metabolismo , Mieloma Múltiple/patología , Proteínas de Neoplasias/biosíntesis , Células Plasmáticas/metabolismo , Células Plasmáticas/patología , Sindecano-1/biosíntesisRESUMEN
The serine/threonine-protein kinase B-raf (BRAF) is an oncogene mutated in various neoplasms, including 5-15% of colorectal carcinomas. The T1799A point mutation, responsible for a large majority of these alterations, results in an amino acid substitution (V600E) causing the constitutive activation of a protein kinase cascade. BRAF V600E in MLH1 deficient tumors implicates somatic tumor-only methylation of the MLH1 promoter region instead of a germline MLH1 mutation. BRAF V600E also predicts poor prognosis in microsatellite stable colorectal cancers and may be a marker of resistance to anti-EGFR therapy in metastatic disease. Currently, only molecular methods are available for assessing BRAF mutational status. An immunohistochemical approach is evaluated here. Colon cancers from 2008 to 2012 tested by pyrosequencing for BRAF V600E mutation were selected. A total of 31 tumors with (n = 14) and without (n = 17) the BRAF V600E mutation were analyzed by immunohistochemistry using a commercially available antibody specific to the V600E-mutated protein. All 14 colorectal carcinomas with the BRAF V600E mutation demonstrated cytoplasmic positivity in tumor cells with the anti-BRAF antibody. In a minority of cases, staining intensity for the mutated tumor samples was weak (n = 2) or heterogeneous (n = 4); however, the majority of cases showed diffuse, strong cytoplasmic positivity (8 of 14 cases). None of the 17 BRAF wild-type colorectal cancers showed immunoreactivity to the antibody. The overall sensitivity and specificity of the immunohistochemical BRAF V600E assay was 100%. Detection of the BRAF V600E mutation in colorectal cancer by immunohistochemistry is a viable alternative to molecular methods.
Asunto(s)
Neoplasias Colorrectales/genética , Inmunohistoquímica/métodos , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Adaptadoras Transductoras de Señales/genética , Anticuerpos Monoclonales/genética , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/aislamiento & purificación , Neoplasias Colorrectales/patología , Mutación de Línea Germinal/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Homólogo 1 de la Proteína MutL , Proteínas Nucleares/genética , Mutación Puntual/genética , Proteínas Proto-Oncogénicas B-raf/aislamiento & purificaciónRESUMEN
ß-Catenin has a dual function in cells: fortifying cadherin-based adhesion at the plasma membrane and activating transcription in the nucleus. We found that in melanoma cells, WNT5A stimulated the disruption of N-cadherin and ß-catenin complexes by activating the guanosine triphosphatase adenosine diphosphate ribosylation factor 6 (ARF6). Binding of WNT5A to the Frizzled 4-LRP6 (low-density lipoprotein receptor-related protein 6) receptor complex activated ARF6, which liberated ß-catenin from N-cadherin, thus increasing the pool of free ß-catenin, enhancing ß-catenin-mediated transcription, and stimulating invasion. In contrast to WNT5A, the guidance cue SLIT2 and its receptor ROBO1 inhibited ARF6 activation and, accordingly, stabilized the interaction of N-cadherin with ß-catenin and reduced transcription and invasion. Thus, ARF6 integrated competing signals in melanoma cells, thereby enabling plasticity in the response to external cues. Moreover, small-molecule inhibition of ARF6 stabilized adherens junctions, blocked ß-catenin signaling and invasiveness of melanoma cells in culture, and reduced spontaneous pulmonary metastasis in mice, suggesting that targeting ARF6 may provide a means of inhibiting WNT/ß-catenin signaling in cancer.
Asunto(s)
Factores de Ribosilacion-ADP/fisiología , Melanoma/patología , Invasividad Neoplásica , Metástasis de la Neoplasia , Proteínas Proto-Oncogénicas/fisiología , Activación Transcripcional/fisiología , Proteínas Wnt/fisiología , beta Catenina/fisiología , Factor 6 de Ribosilación del ADP , Silenciador del Gen , Humanos , Transducción de Señal , Proteína Wnt-5a , beta Catenina/metabolismoRESUMEN
CONTEXT: Molecular genotyping by analysis of DNA microsatellites, also known as short tandem repeats (STRs), is an established method for diagnosing and classifying hydatidiform mole. Distinction of both complete hydatidiform mole and partial hydatidiform mole from nonmolar specimens is relevant for clinical management owing to differences in risk for persistent gestational trophoblastic disease. OBJECTIVE: To determine the technical performance of microsatellite genotyping by using a commercially available multiplex assay, and to describe the application of additional methods to confirm other genetic abnormalities detected by the genotyping assay. DESIGN: Microsatellite genotyping data on 102 cases referred for molar pregnancy testing are presented. A separate panel of mini STR markers, flow cytometry, fluorescence in situ hybridization, and p57 immunohistochemistry were used to characterize cases with other incidental genetic abnormalities. RESULTS: Forty-eight cases were classified as hydatidiform mole (31, complete hydatidiform mole; 17, partial hydatidiform mole). Genotyping also revealed 11 cases of suspected trisomy and 1 case of androgenetic/biparental mosaicism. Trisomy for selected chromosomes (13, 16, 18, and 21) was confirmed in all cases by using a panel of mini STR markers. CONCLUSIONS: This series illustrates the utility of microsatellite genotyping as a stand-alone method for accurate classification of hydatidiform mole. Other genetic abnormalities may be detected by genotyping; confirmation of the suspected abnormality requires additional testing.
Asunto(s)
Técnicas de Genotipaje/métodos , Mola Hidatiforme/diagnóstico , Mola Hidatiforme/genética , Repeticiones de Microsatélite , Neoplasias Uterinas/diagnóstico , Neoplasias Uterinas/genética , Bacterias , Femenino , Citometría de Flujo , Humanos , Mola Hidatiforme/clasificación , Inmunohistoquímica , Hibridación Fluorescente in Situ , Masculino , Mosaicismo , Embarazo , Coloración y Etiquetado , Trisomía , Neoplasias Uterinas/clasificaciónRESUMEN
Atypical intradermal smooth muscle neoplasms (AISMN, formerly known as cutaneous leiomyosarcomas) are uncommon neoplasms, which seem to be remarkable for their excellent prognosis in contrast to their deeper counterparts. The rarity of AISMN has posed a challenge for characterizing the morphologic spectrum, immunohistochemical staining pattern, and behavior. In this study we evaluated the histologic and immunohistochemical features of 20 cases of AISMN. Clinical follow-up was available on 19 out of 20 patients and ranged from 1 to 124 months with an average of 35 months and a median of 20 months with a male predominance (male to female ratio was 2.3:1). Our data show a wide variation in differentiation and atypical features. Among these, the presence of mitotic figures is diagnostically valuable in rendering the final diagnosis. A broad panel of immunohistochemical stains revealed that smooth muscle actin and muscle specific actin, when used in combination, identified smooth muscle differentiation in 100% of the cases. With some caveats, CD34, S100, and CK 5/6 were helpful in ruling out other important cutaneous spindle cell neoplasms. Significantly, loss of phosphatase and tensin homolog (PTEN) staining was seen in the majority of our cases (80%), supporting a role for PTEN loss in the etiology of these lesions. Logistic regression analysis revealed that positive margin status was helpful for predicting recurrence (100% sensitivity and 94% specificity). We conclude that AISMN can have significant morphologic variation and overlap with other spindle cell neoplasms of the skin and that a limited panel of key immunohistochemical stains should be used to distinguish this lesion. The different surgical measures such as wide excision versus Mohs procedure showed a similar clinical outcome. Although the significance of frequent PTEN loss supports a molecular mechanism of tumor genesis, the diagnostic utility of the stain remains to be determined.