Erythroid induction of K562 cells treated with mithramycin is associated with inhibition of raptor gene transcription and mammalian target of rapamycin complex 1 (mTORC1) functions
| Autor: | Jessica Gasparello, Monica Borgatti, Roberto Gambari, Giulia Breveglieri, Enrica Fabbri, Nicoletta Bianchi, Alessia Finotti |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
Sp1
specific protein 1 EMSA electrophoretic mobility shift assay Cellular differentiation Gene Expression mTORC1 0302 clinical medicine Mithramycin hemic and lymphatic diseases Gene expression TBS tris-buffered saline Promoter Regions Genetic Erythroid induction MTH mithramycin 0303 health sciences TOR Serine-Threonine Kinases Rictor rapamycin-insensitive companion of mTOR Cell Cycle Cell Differentiation Plicamycin Fetal hemoglobin Pyrrolidonecarboxylic Acid 3. Good health Raptor ChIP chromatin immunoprecipitation Raptor mTOR Sp1 Mithramycin Erythroid induction Fetal hemoglobin 030220 oncology & carcinogenesis mTOR ODN oligonucleotide Oligopeptides HbF fetal hemoglobin Sp1 PBS phosphate-buffered saline P70-S6 Kinase 1 mTOR mammalian target of rapamycin Mechanistic Target of Rapamycin Complex 1 Biology Article NO 03 medical and health sciences FBS fetal bovine serum Humans m-TORC2 mTOR complex 2 RNA Messenger PI3K/AKT/mTOR pathway ComputingMethodologies_COMPUTERGRAPHICS Adaptor Proteins Signal Transducing 030304 developmental biology Pharmacology Sp1 transcription factor Raptor regulatory associated protein of mTOR RAPA rapamycin Regulatory-Associated Protein of mTOR Molecular biology Rapamycin-Insensitive Companion of mTOR Protein Multiprotein Complexes mTORC1 mTOR complex 1 Carrier Proteins K562 Cells Chromatin immunoprecipitation K562 cells |
| Zdroj: | Pharmacological Research |
| Popis: | Graphical abstract Rapamycin, an inhibitor of mTOR activity, is a potent inducer of erythroid differentiation and fetal hemoglobin production in β-thalassemic patients. Mithramycin (MTH) was studied to see if this inducer of K562 differentiation also operates through inhibition of mTOR. We can conclude from the study that the mTOR pathway is among the major transcript classes affected by mithramycin-treatment in K562 cells and a sharp decrease of raptor protein production and p70S6 kinase is detectable in mithramycin treated K562 cells. The promoter sequence of the raptor gene contains several Sp1 binding sites which may explain its mechanism of action. We hypothesize that the G + C-selective DNA-binding drug mithramycin is able to interact with these sequences and to inhibit the binding of Sp1 to the raptor promoter due to the following results: (a) MTH strongly inhibits the interactions between Sp1 and Sp1-binding sites of the raptor promoter (studied by electrophoretic mobility shift assays, EMSA); (b) MTH strongly reduces the recruitment of Sp1 transcription factor to the raptor promoter in intact K562 cells (studied by chromatin immunoprecipitation experiments, ChIP); (c) Sp1 decoy oligonucleotides are able to specifically inhibit raptor mRNA accumulation in K562 cells. In conclusion, raptor gene expression is involved in mithramycin-mediated induction of erythroid differentiation of K562 cells and one of its mechanism of action is the inhibition of Sp1 binding to the raptor promoter. |
| Databáze: | OpenAIRE |
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