A PU.1 suppressive target gene, metallothionein 1G, inhibits retinoic acid-induced NB4 cell differentiation

• Published in: PloS one Vol. 9; no. 7; p. e103282
• Main Authors: Hirako, Naomi, Nakano, Hiroko, Takahashi, Shinichiro
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 29.07.2014; Public Library of Science (PLoS)
• Subjects: Acids; Acute promyeloid leukemia; Analysis; Antigens, CD - genetics; Antigens, CD - metabolism; Apoptosis; B cells; Biology and Life Sciences; c-Myc protein; Calcium; Calcium-binding protein; CAP37 protein; Carboxylate reductase; CD11b antigen; CD11c antigen; Cell cycle; Cell differentiation; Cell Differentiation - drug effects; Cell Line, Tumor; Cyclin D1; Cyclin-dependent kinase inhibitor p21; Deoxyribonucleic acid; Differentiation (biology); DNA; DNA microarrays; Epigenetic inheritance; Flow cytometry; G1 Phase Cell Cycle Checkpoints - drug effects; G1 Phase Cell Cycle Checkpoints - genetics; Gene Expression; Gene Expression Profiling; Gene Expression Regulation; Genes; Health sciences; Hematology; Humans; Immunophenotyping; Leukemia; Leukemia, Promyelocytic, Acute - genetics; Leukemia, Promyelocytic, Acute - metabolism; Leukemia, Promyelocytic, Acute - pathology; Medicine and Health Sciences; Metalloproteinase; Metallothionein; Metallothionein - genetics; Myc protein; Myeloid cells; Neutrophils; Oncostatin M; Oxidative stress; Peroxidase; Promyeloid leukemia; Protein binding; Proteins; Proto-Oncogene Proteins - metabolism; PU.1 protein; Pyrroline-5-carboxylate reductase; Reproducibility of Results; Retinoic acid; Rodents; Trans-Activators - metabolism; Transcription factors; Tretinoin; Tretinoin - pharmacology; Tumors; Japan
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0103282

We recently revealed that myeloid master regulator SPI1/PU.1 directly represses metallothionein (MT) 1G through its epigenetic activity of PU.1, but the functions of MT1G in myeloid differentiation remain unknown. To clarify this, we established MT1G-overexpressing acute promyelocytic leukemia NB4 (NB4MTOE) cells, and investigated whether MT1G functionally contributes to all-trans retinoic acid (ATRA)-induced NB4 cell differentiation. Real-time PCR analyses demonstrated that the inductions of CD11b and CD11c and reductions in myeloperoxidase and c-myc by ATRA were significantly attenuated in NB4MTOE cells. Morphological examination revealed that the percentages of differentiated cells induced by ATRA were reduced in NB4MTOE cells. Since G1 arrest is a hallmark of ATRA-induced NB4 cell differentiation, we observed a decrease in G1 accumulation, as well as decreases in p21WAF1/CIP1 and cyclin D1 inductions, by ATRA in NB4MTOE cells. Nitroblue tetrazolium (NBT) reduction assays revealed that the proportions of NBT-positive cells were decreased in NB4MTOE cells in the presence of ATRA. Microarray analyses showed that the changes in expression of several myeloid differentiation-related genes (GATA2, azurocidin 1, pyrroline-5-carboxylate reductase 1, matrix metallopeptidase -8, S100 calcium-binding protein A12, neutrophil cytosolic factor 2 and oncostatin M) induced by ATRA were disturbed in NB4MTOE cells. Collectively, overexpression of MT1G inhibits the proper differentiation of myeloid cells.