RESUMO
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.
Assuntos
Proteínas Hedgehog/metabolismo , Linfoma de Células B/metabolismo , Transdução de Sinais , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Proteínas Hedgehog/genética , Humanos , Ligantes , Linfoma de Células B/genética , Linfoma de Células B/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas Oncogênicas/genética , Proteínas Oncogênicas/metabolismo , Fenótipo , Proteínas Proto-Oncogênicas/deficiência , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2 , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Células Estromais/metabolismo , Taxa de Sobrevida , Transativadores/genética , Transativadores/metabolismo , Alcaloides de Veratrum/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto , Proteína GLI1 em Dedos de ZincoRESUMO
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.
Assuntos
Proliferação de Células , Proteínas de Fusão bcr-abl/metabolismo , Proteínas Hedgehog/fisiologia , Células-Tronco Neoplásicas/patologia , Transdução de Sinais/fisiologia , Animais , Apoptose/efeitos dos fármacos , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/metabolismo , Células da Medula Óssea/patologia , Transplante de Medula Óssea , Quimioterapia Combinada , Células-Tronco Fetais/citologia , Células-Tronco Fetais/metabolismo , Células-Tronco Fetais/transplante , Proteínas de Fusão bcr-abl/genética , Expressão Gênica/efeitos dos fármacos , Hematopoese/efeitos dos fármacos , Hematopoese/fisiologia , Humanos , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Receptores Patched , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais/efeitos dos fármacos , Receptor Smoothened , Análise de Sobrevida , Alcaloides de Veratrum/farmacologia , Alcaloides de Veratrum/uso terapêutico , Proteína GLI1 em Dedos de ZincoRESUMO
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.