RESUMEN
Resistance of Bcr-Abl-positive leukemic stem cells (LSCs) to imatinib treatment in patients with chronic myeloid leukemia (CML) can cause relapse of disease and might be the origin for emerging drug-resistant clones. In this study, we identified Smo as a drug target in Bcr-Abl-positive LSCs. We show that Hedgehog signaling is activated in LSCs through upregulation of Smo. While Smo(-/-) does not impact long-term reconstitution of regular hematopoiesis, the development of retransplantable Bcr-Abl-positive leukemias was abolished in the absence of Smo expression. Pharmacological Smo inhibition reduced LSCs in vivo and enhanced time to relapse after end of treatment. Our results indicate that Smo inhibition might be an effective treatment strategy to reduce the LSC pool in CML.
Asunto(s)
Proliferación Celular , Proteínas de Fusión bcr-abl/metabolismo , Proteínas Hedgehog/fisiología , Células Madre Neoplásicas/patología , Transducción de Señal/fisiología , Animales , Apoptosis/efectos de los fármacos , Células de la Médula Ósea/efectos de los fármacos , Células de la Médula Ósea/metabolismo , Células de la Médula Ósea/patología , Trasplante de Médula Ósea , Quimioterapia Combinada , Células Madre Fetales/citología , Células Madre Fetales/metabolismo , Células Madre Fetales/trasplante , Proteínas de Fusión bcr-abl/genética , Expresión Génica/efectos de los fármacos , Hematopoyesis/efectos de los fármacos , Hematopoyesis/fisiología , Humanos , Factores de Transcripción de Tipo Kruppel/genética , Factores de Transcripción de Tipo Kruppel/metabolismo , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Leucemia Mielógena Crónica BCR-ABL Positiva/metabolismo , Leucemia Mielógena Crónica BCR-ABL Positiva/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Células Madre Neoplásicas/efectos de los fármacos , Células Madre Neoplásicas/metabolismo , Receptores Patched , Pirimidinas/farmacología , Pirimidinas/uso terapéutico , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismo , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Transducción de Señal/efectos de los fármacos , Receptor Smoothened , Análisis de Supervivencia , Alcaloides de Veratrum/farmacología , Alcaloides de Veratrum/uso terapéutico , Proteína con Dedos de Zinc GLI1RESUMEN
Interaction of cancer cells with their microenvironment generated by stromal cells is essential for tumor cell survival and influences the localization of tumor growth. Here we demonstrate that hedgehog ligands secreted by bone-marrow, nodal and splenic stromal cells function as survival factors for malignant lymphoma and plasmacytoma cells derived from transgenic Emu-Myc mice or isolated from humans with these malignancies. Hedgehog pathway inhibition in lymphomas induced apoptosis through downregulation of Bcl2, but was independent of p53 or Bmi1 expression. Blockage of hedgehog signaling in vivo inhibited expansion of mouse lymphoma cells in a syngeneic mouse model and reduced tumor mass in mice with fully developed disease. Our data indicate that stromally induced hedgehog signaling may provide an important survival signal for B- and plasma-cell malignancies in vitro and in vivo. Disruption of this interaction by hedgehog pathway inhibition could provide a new strategy in lymphoma and multiple myeloma therapy.
Asunto(s)
Proteínas Hedgehog/metabolismo , Linfoma de Células B/metabolismo , Transducción de Señal , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , Proteínas Hedgehog/genética , Humanos , Ligandos , Linfoma de Células B/genética , Linfoma de Células B/patología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Proteínas Oncogénicas/genética , Proteínas Oncogénicas/metabolismo , Fenotipo , Proteínas Proto-Oncogénicas/deficiencia , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2 , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/metabolismo , Neoplasias Cutáneas/patología , Células del Estroma/metabolismo , Tasa de Supervivencia , Transactivadores/genética , Transactivadores/metabolismo , Alcaloides de Veratrum/farmacología , Ensayos Antitumor por Modelo de Xenoinjerto , Proteína con Dedos de Zinc GLI1RESUMEN
Rapid quantitative methods for characterizing small molecules, peptides, proteins, or RNAs in a broad array of cellular assays would allow one to discover new biological activities associated with these molecules and also provide a more comprehensive profile of drug candidates early in the drug development process. Here we describe a robotic system, termed the automated compound profiler, capable of both propagating a large number of cell lines in parallel and assaying large collections of molecules simultaneously against a matrix of cellular assays in a highly reproducible manner. To illustrate its utility, we have characterized a set of 1,400 kinase inhibitors in a panel of 35 activated tyrosine-kinase-dependent cellular assays in dose-response format in a single experiment. Analysis of the resulting multidimensional dataset revealed subclusters of both inhibitors and kinases with closely correlated activities. The approach also identified activities for the p38 inhibitor BIRB796 and the dual src/abl inhibitor BMS-354825 and exposed the expected side activities for Glivec/STI571, including cellular inhibition of c-kit and platelet-derived growth factor receptor. This methodology provides a powerful tool for unraveling the cellular biology and molecular pharmacology of both naturally occurring and synthetic chemical diversity.