ABSTRACT
TRAP1 (Hsp75) is the mitochondrial paralog of the Hsp90 molecular chaperone family. Due to structural similarity among Hsp90 chaperones, a potential strategy to induce apoptosis through mitochondrial TRAP1 ATPase inhibition has been envisaged and a series of compounds has been developed by binding the simple pharmacophoric core of known Hsp90 inhibitors with various appendages bearing a permanent cationic head, or a basic group highly ionizable at physiologic pH. Cationic appendages were selected as vehicles to deliver drugs to mitochondria. Indeed, masses of new derivatives were evidenced to accumulate in the mitochondrial fraction from colon carcinoma cells and a compound in the series, with a guanidine appendage, demonstrated good activity in inhibiting recombinant TRAP1 ATPase and cell growth and in inducing apoptotic cell death in colon carcinoma cells.
Subject(s)
HSP90 Heat-Shock Proteins/antagonists & inhibitors , Isoxazoles/pharmacology , Mitochondria/metabolism , Adenosine Triphosphatases/antagonists & inhibitors , Apoptosis/drug effects , Cell Proliferation/drug effects , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Guanidines/chemical synthesis , Guanidines/chemistry , Guanidines/pharmacology , HCT116 Cells , Humans , Isoxazoles/chemical synthesis , Isoxazoles/chemistry , Molecular Structure , Onium Compounds/chemical synthesis , Onium Compounds/chemistry , Onium Compounds/pharmacology , Organophosphorus Compounds/chemical synthesis , Organophosphorus Compounds/chemistry , Organophosphorus Compounds/pharmacology , Pyridinium Compounds/chemical synthesis , Pyridinium Compounds/chemistry , Pyridinium Compounds/pharmacologyABSTRACT
Acute myeloid leukemia (AML) blasts are immature committed myeloid cells unable to spontaneously undergo terminal maturation, and characterized by heterogeneous sensitivity to natural differentiation inducers. Here, we show a molecular signature predicting the resistance or sensitivity of six myeloid cell lines to differentiation induced in vitro with retinoic acid or vitamin D. The identified signature was further validated by TaqMan assay for the prediction of response to an in vitro differentiation assay performed on 28 freshly isolated AML blast populations. The TaqMan assay successfully predicts the in vitro resistance or responsiveness of AML blasts to differentiation inducers. Furthermore, performing a meta-analysis of publicly available microarray data sets, we also show the accuracy of our prediction on known phenotypes and suggest that our signature could become useful for the identification of patients eligible for new therapeutic strategies.
Subject(s)
Antineoplastic Agents/pharmacology , Drug Resistance, Neoplasm/genetics , Leukemia, Myeloid/drug therapy , Leukemia, Myeloid/genetics , Tretinoin/pharmacology , Acute Disease , Cell Differentiation/drug effects , Cell Line, Tumor , Cluster Analysis , Databases, Factual , Gene Expression Regulation, Leukemic/drug effects , Humans , Leukemia, Myeloid/pathology , Meta-Analysis as Topic , Oligonucleotide Array Sequence Analysis , Predictive Value of Tests , Reverse Transcriptase Polymerase Chain Reaction , Vitamin D/pharmacology , Vitamins/pharmacologyABSTRACT
Upregulation of specific transcription factors is a generally accepted mechanism to explain the commitment of hematopoietic stem cells along precise maturation lineages. Based on this premise, transduction of primary hematopoietic stem/progenitor cells with viral vectors containing the investigated transcription factors appears as a suitable experimental model to identify such regulators. Although MafB transcription factor is believed to play a role in the regulation of monocytic commitment, no demonstration is, to date, available supporting this function in normal human hematopoiesis. To address this issue, we retrovirally transduced cord blood CD34+ hematopoietic progenitors with a MafB cDNA. Immunophenotypic and morphological analysis of transduced cells demonstrated the induction of a remarkable monomacrophage differentiation. Microarray analysis confirmed these findings and disclosed the upregulation of macrophage-related transcription factors belonging to the AP-1, MAF, PPAR and MiT families. Altogether our data allow to conclude that MafB is a key regulator of human monocytopoiesis.
Subject(s)
Hematopoietic Stem Cells/cytology , Hematopoietic Stem Cells/metabolism , MafB Transcription Factor/genetics , MafB Transcription Factor/metabolism , Monocytes/cytology , Monocytes/metabolism , Antigens, CD34/metabolism , Cell Line , Colony-Forming Units Assay , DNA, Complementary/genetics , Fetal Blood/cytology , Fetal Blood/immunology , Fetal Blood/metabolism , Gene Expression Profiling , Hematopoietic Stem Cells/immunology , Humans , In Vitro Techniques , Infant, Newborn , MafB Transcription Factor/antagonists & inhibitors , Monocytes/immunology , Myelopoiesis , Oligonucleotide Array Sequence Analysis , RNA, Small Interfering/genetics , Retroviridae/genetics , Transduction, Genetic , Up-RegulationABSTRACT
In spite of their apparently restricted differentiation potentiality, hematopoietic precursors are plastic cells able to trans-differentiate from a maturation lineage to another. To better characterize this differentiation plasticity, we purified CD14- and CD14+ myeloid precursors generated by 'in vitro' culture of human CD34+ hematopoietic progenitors. Morphological analysis of the investigated cell populations indicated that, as expected, they consisted of granulocyte and monocyte precursors, respectively. Treatment with differentiation inducers revealed that CD14- cells were bipotent granulo-monocyte precursors, while CD14+ cells appeared univocally committed to a terminal macrophage maturation. Flow cytometry analysis demonstrated that the conversion of granulocyte precursors to the mono-macrophage maturation lineage occurs through a differentiation transition in which the granulocyte-related myeloperoxidase enzyme and the monocyte-specific CD14 antigen are co-expressed. Expression profiling evidenced that the observed trans-differentiation process was accompanied by a remarkable upregulation of the monocyte-related MafB transcription factor.
