Differentiation Of M1 Cells Research Articles

Acidic isoferritins do not suppress differentiation of mouse myeloid leukemic M1 cells

The differentiation of mouse myeloid leukemia line cells (M1) into macrophages or granulocytes has been reported. Resistant M1 cells which did not differentiate even with a high concentration of inducer of differentiation were isolated from M1 cells. The conditioned medium of the resistant M1 cells (RCM) inhibited the induction of differentiation of M1 cells and the formation of macrophage and granulocyte colonies of normal mouse bone marrow cells. Acidic isoferritins known as negative regulators of normal bone marrow cells (CFU-GM) failed to inhibit the induction of differentiation and growth of M1 cells. The RCM treated with anti-acidic isoferritin serum could inhibit the induction of differentiation of M1 cells as did the untreated RCM. The activities, in RCM, inhibiting growth and differentiation of the normal bone marrow cells were partly neutralized by treatment with the antiserum but most of the activities remained. These results suggest that growth and differentiation of the mouse myeloid leukemia M1 cells are not regulated by acidic isoferritins and other inhibitory activities affecting normal bone marrow colony formation, in addition to acidic isoferritins, are released from M1 cells.

Studies on the differentiation inducers of myeloid leukemic cells. II. citrinin, a new inducer of the differentiation of M1 cells.

Studies on the differentiation inducers of myeloid leukemic cells. II. citrinin, a new inducer of the differentiation of M1 cells.

1 alpha,25-Dihydroxyvitamin D3 and 1 alpha-hydroxyvitamin D3 prolong survival time of mice inoculated with myeloid leukemia cells.

Syngeneic SL mice inoculated with murine myeloid leukemia cells (M1) all died of leukemia within 30 days. Treatment three times a week with 12.5-50 pmol per mouse of either 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3], the active form of vitamin D3, or its synthetic analog, 1 alpha-hydroxyvitamin D3 [1 alpha(OH)D3], considerably prolonged the survival time of mice inoculated with M1 cells. 1 alpha(OH)D3 was more effective than 1 alpha,25(OH)2D3 in increasing the survival time of the mice. 1 alpha(OH)D3 also increased the survival time of nude mice inoculated with M1 cells. The 1 alpha(OH)[3H]D3 administered intraperitoneally to tumor-bearing mice was converted very rapidly to 1 alpha,25(OH)2-[3H]D3. The chronic administration of 25 pmol of 1 alpha(OH)D3 to tumor-bearing mice for 30 days caused no appreciable hypercalcemia. These results indicate clearly that 1 alpha,25(OH)2D3 is effective not only in inducing differentiation of M1 cells in vitro, as previously reported [Abe, E., Miyaura, C., Sakagami, H., Takeda, M., Konno, K., Yamazaki, T., Yoshiki, S. & Suda, T. (1981) Proc. Natl. Acad. Sci. USA 78, 4990-4994], but also in prolonging the survival time of mice inoculated with M1 cells.

Modification of membrane phospholipid composition by choline analogues induces differentiation of cultured mouse myeloid leukemia cells

Mouse myeloid leukemia M1 cells could be induced by various inducers to form Fc receptors, phagocytize, produce lysozyme, and change into forms that were morphologically similar to macrophages and granulocytes. Previous experiments showed that change in phospholipid metabolism was associated with cell differentiation. In the present experiment, culture of M1 cells with choline analogs such as N-monomethylethanolamine and N, N′-dimethylethanolamine resulted in accumulation of phosphatidyl- N-monomethylethanolamine and phosphatidyl- N, N′-dimethylethanolamine in the cell membranes. This change upon treatment with choline analogs was associated with morphological and functional differentiation of the M1 cells into macrophages and granulocytes. These results suggest that phospholipid metabolism is involved in the mechanism of differentiation of M1 cells.

The occurrence of lysozyme activity in nuclei of a differentiated mouse myeloid leukemia cell line.

Mouse myeloid leukemia (Ml) cells that were induced to differentiate with dexamethasone showed at least a 100-fold increase in lysozyme activity. This induced activity was distributed in various subcellular fractions, the molecular weights of which were nearly identical. The activity detected in the nuclear fraction (nearly one-third that of the total number of cells) could be extracted completely with 0.3 M NaCl or 0.4 N H2SO4, but not with 0.74 M perchloric acid. When nuclei were incubated with DNase I or micrococcal nuclease, the release of lysozyme showed a positive relation to increased digestion of DNA. The lysozyme, released by treatment with micrococcal nuclease, was distributed throughout the region of the multimers of nucleosomes after centrifugation on a 5-20 % linear sucrose gradient. Our results suggest that a part of the lysozyme activity induced during M1 cell differentiation may be associated with chromatin DNA.

Studies on the differentiation inducers of myeloid leukemic cells. I. Latosillan, a new inducer of the differentiation of M1 cells.

Studies on the differentiation inducers of myeloid leukemic cells. I. Latosillan, a new inducer of the differentiation of M1 cells.

Effect of p-aminobenzoic acid N-xyloside sodium salt (K-247) on metabolism and functions of normal lymphocytes and leukemic cells.

An N-xyloside derivative of p-aminobenzoic acid, K-247, was investigated for the ability to induce changes of Phospholipid metabolism and membrane transport in murine splenic lymphocytes and leukemic cells. K-247 induced an increase of [3H] methyl group incorporation into phospholipid in both normal lymphocytes and leukemic cells (L-1210 and M1 cells). However, K-247 accelerated the turnover of phosphatidylinositol (PI) measured by [32P] incorporation into PI in L-1210 cells and Ml cells but not in normal lymphocytes. 45Ca2+ influx into normal lymphocytes and leukemic cells was also increased by K-247. A methyltransferase inhibitor, 5'-deoxy-5'-S-isobutyl adenosine (SIBA), suppressed both the increase of phospholipid methylation and that of Ca2+ influx. It seemed that Ca2+ transport might be regulated by membrane phospholipid methylation. On the other hand, K-247 was found to suppress [3H] aminoisobutylic acid (AIB) uptake into L-1210 cells and Ml cells. Protein synthesis in L-1210 cells and Ml cells slightly decreased but RNA and DNA syntheses in both normal and leukemic cells were not affected by K-247. These results suggest that K-247 mainly acts on cell membranes, which are more sensitive to K-247 in leukemic cells than in normal lymphocytes. K-247 also induced differentiation of Ml cells into macrophages and granulocytes with phagocytic activity and morphological characteristics. Moreover, K-247 elevated the Con A response of murine thymocytes, most of which were immature T cells and had low reactivity to Con A, and caused a decrease of Thy 1.2 antigen on thymocytes. It seemed that K-247 also affected maturation of thymocytes.

A cell surface marker expressed on cytotoxic peritoneal macrophages and normal lung macrophages.

The Ml cell line (Clone M1/436.7) established from a myeloid leukemia of an SL strain mouse by Y. Ichikawa (1) is known to be inducible to differentiate into mature macrophages by exposure to various inducers, such as lipopolysaccharide (LPS) (2). Employing these clonal cells, we tested various macrophage activating agents for their possible differentiation inducing ability. As summarized in Figure 1, crude lymphokines, obtained by stimulating normal mouse spleen cells with concanavalin A-agarose, induced Ml cell differentiation, while neither purified interferon (IFN; 107.3 units/mg; given by Haruo Kono, NIH, Tokyo) nor synthetic muramyl dipeptide (MDP) did so (3,4). Instead, IFN enhanced Ml cell differentiation triggered by LPS or lymphokines, and MDP acted on matured M1 cells to produce factor(s) which could trigger M1 cell differentiation (4).

Induction and function of 2′,5′-oligoadenylate synthetase in differentiation of mouse myeloid leukemia cells

The activity of 2′,5′-oligoadenylate synthetase (2-5A synthetase), known to be induced by interferon, was detected in mouse myeloid leukemic M1 cells only when they differentiated to phagocytic cells after incubation with conditioned medium (CM) from rat embryo cells. However, no interferon activity occurred in culture fluids of CM-treated M1 cells, although some activity was detected in the cell extracts. When anti-interferon serum was added to M1 cell cultures, the induction of 2-5A synthetase by CM was suppressed. These results suggest that CM stimulated the M1 cells to produce a minute amount of interferon, which was reponsible for induction of the 2-5A synthetase activity. On the other hand, development of the phagocytic activity of M1 cells could not be influenced by addition of antiserum. Interferon added exogenously per se neither induced phagocytic activity of M1 cells, nor did it enhance the CM-induced differentiation of the cells. Moreover, dexamethasone, which induced differentiation of M1 cells, was not capable of inducing 2-5A synthetase. These results indicate that interferon and/or 2-5A synthetase plays no essential part in the differentiation of M1 cells.

Close Association of Mouse Myeloid Leukemia (M1) Cell Differentiation with Cessation of DNA Synthesis

Mouse myeloid leukemia cells (M1) were induced to different-iate in vitro by treatment with dexamethasone. The incorporation of [3H] thymidine into acid-insoluble materials began to decline after 10 h treatment. This reflected the differentiation-associated decline of DNA synthesis activity, since (i) the thymidine was almost exclusively incorporated into nuclear DNA, (ii) the incorporation was completely blocked by arabinofuranosylcytosine and (iii) the differentiation-associated changes of intracellular pool size and specific activity of thymidine were negligible. Cell fractionation by discontinuous Ficoll-Urografin density gradients revealed that the DNA synthesis of the differentiat-ed cells declined with the decreased density, or ratio of nucleus size to cell size (N/C ratio). Autoradiographic analysis showed that the decrease in DNA synthesis activity was due to the accumulation of unlabeled cells, which exhibited a much lower N/C ratio than labeled cells. Dexamethasone treat-ment also caused specific reduction in the proportion of S phase cells. These results indicate that M1 cell differentiation is closely coupled with the cessation of DNA synthesis.

Differentiation-associated changes in membrane proteins of mouse myeloid leukemia cells

The mouse myeloid leukemia cell line (M1) is known to differentiate in vitro into macrophages and granulocytes upon treatment with various inducer including mouse ascitic fluid. Changes of cell surface proteins during differentiation of M1 cells were analyzed by the lactoperoxidase-catalyzed radioiodination method and SDS-polycrylamide slab gel electrphoresis. Treatment of the cells with ascitic fluid changed the electrophoretic pattern of the iodinated proteins, the prominent change being the appearance of a new protein with a molecular weight of 180 000 (P180). Iodinated P180 was also detected in normal macrophages in granulocytes, which are similar to differentiated M1 cells. This protein was metabolically labeled with l-[ 14C]fucose, increasing with the period of the treatment. P180 was not expressed on ascitic fluid-treatment of a resistant clone of M1 cells that could not be induced to differentiate. These results indicate that P180 is a glycoprotein that is exposed on the outer surface of differentiated M1 cells, and that its expression is associated with differentiation of the cells. P180 was solubilized from 125I-labeled macrophages with detergents bound to concanavalin A-Sepharose. This suggests that P180 is one of the receptors for concanavalin A. Therefore, P180 may contribute partly to the increases in agglutinability by concanavalin A and in the number of concanavalin A binding sites on the surface of M1 cells, which are known to be associated with differentiation of M1 cells.

A factor inducing differentiation of mouse myeloid leukemia cells in human amniotic fluid.

The M1 line cells of mouse myeloid leukemia can be induced to differentiate in vitro into macrophages by a factor in human amniotic fluid. The macrophages showed phagocytosis and locomotic activity, and also gained Fc receptors on the cell surface. This factor in amniotic fluid capable of inducing differentiation of M1 cells was heat-labile, trypsin-sensitive, and non-dialysable. A growth-stimulating factor for the M1 cells was also found in the human amniotic fluid, and it was heat-stable and trypsin-resistant. The conditioned medium obtained from the amnion had the activity of differentiating the M1 cells.