Cellular analysis of growth suppression induced by the Notch ligands, Delta-1 and Jagged-1 in two myeloid leukemia cell lines.
It is known that Notch activation promotes the self-renewal of hematopoietic cells. However, we have previously found that the growth of a myeloid leukemia cell line, OCI/AML-6, was suppressed by Notch activation induced by stimulation with a recombinant Notch ligand, Delta-1 protein. We recently found that the growth of another leukemia cell line, THP-1, was also suppressed by the ligands Delta-1 and Jagged-1. In this study, we tried to clarify the cellular and molecular mechanism of the growth suppression induced by Notch activation. Flow cytometric analysis showed that Delta-1 stimulation increased the expression of differentiation markers such as CD11b and CD13 while it decreased the expression of CD117 (c-KIT), a marker for primitive cells in THP-1 cells. In OCI/AML-6 cells, Delta-1 stimulation decreased the expression of CD11b and CD14 and increased CD34 expression. Namely, Delta-1 showed the opposite effects on the differentiation markers of each cell line. Delta-1 stimulation did not increase the binding of annexin V, a marker for apoptotic cells in either cell line. Since the growth of myeloid cells is regulated by MAP kinase and JAK/STAT pathways, we investigated the effects of the ligand stimulation on these pathways. Delta-1 stimulation did not induce the phosphorylation of ERK1/2 and STAT3 proteins in either cell line. Pre-exposure to Delta-1 did not affect the phosphorylation of ERK1/2 and STAT3 induced by G-CSF in OCI/AML-6 cells, either. Namely, it is thought that these pathways are not involved in the growth suppression caused by Notch ligands. Our study revealed several findings on Notch function. However, the precise mechanism remains to be elucidated.
Murata-Ohsawa
Mai
M
Department of Laboratory Medicine, Tokyo Medical and Dental University, Tokyo 113-8519, Japan.
Tohda
Shuji
S
Nara
Nobuo
N
D017304:Annexin A5 / Q000494:pharmacology; D017209:Apoptosis; D039481:CD11b Antigen / Q000096:biosynthesis; D018826:CD13 Antigens / Q000096:biosynthesis; D002135:Calcium-Binding Proteins; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D016179:Granulocyte Colony-Stimulating Factor / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; D000072100:Jagged-1 Protein; D007951:Leukemia, Myeloid / Q000378:metabolism*; D008024:Ligands; D020935:MAP Kinase Signaling System; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D010766:Phosphorylation; D019009:Proto-Oncogene Proteins c-kit / Q000096:biosynthesis; D051880:Receptors, Notch; D011994:Recombinant Proteins / Q000378:metabolism; D000072099:Serrate-Jagged Proteins; D013997:Time Factors
D017304:Annexin A5; D039481:CD11b Antigen; D002135:Calcium-Binding Proteins; D004791:Enzyme Inhibitors; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; C000606273:JAG1 protein, human; D000072100:Jagged-1 Protein; D008024:Ligands; D008565:Membrane Proteins; D051880:Receptors, Notch; D011994:Recombinant Proteins; D000072099:Serrate-Jagged Proteins; C064045:delta protein; D016179:Granulocyte Colony-Stimulating Factor; D019009:Proto-Oncogene Proteins c-kit; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D018826:CD13 Antigens