Tohda Shuji, Kogoshi Hanae, Murakami Naomi, Sakano Seiji, Nara Nobuo
Department of Laboratory Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
Exp Hematol. 2005 May;33(5):558-63. doi: 10.1016/j.exphem.2005.01.010.
Notch signaling plays a role in regulating the self-renewal and differentiation of hematopoietic progenitors. Since acute myeloblastic leukemia (AML) originates from dysregulated hematopoietic progenitors, the Notch system may be involved in the abnormal growth. We previously reported that AML cells express Notch proteins. In this study, we examined the effects of recombinant human Notch ligand proteins, Jagged1 and Delta1, on the growth and differentiation of primary AML cells.
AML cells separated from blood from 12 patients were cultured in wells coated with Jagged1, Delta1, or control IgG. The short-term growth was evaluated using a colorimetric assay. The self-renewal capacity was evaluated by the clonogenic cells recovered, which were obtained via a colony assay involving cells cultured with the ligands or control IgG. Differentiation was evaluated by the morphology of the cultured cells and flow cytometric analysis.
The ligand stimulation caused three types of response in the short-term growth of the primary AML cells, namely, promotion, suppression, or no significant effect. The self-renewal capacity was suppressed or not significantly affected by the ligands, even in cells showing short-term growth promotion. The ligand stimulation altered blast cells into macrophage-like cells from their morphology and increased the expression of differentiation markers such as CD13 or CD14 in some samples.
The Notch ligands had diverse effects on the short-term growth of primary AML cells. The ligands did not promote the self-renewal capacity of any of the cells examined and instead tended to induce differentiation under the conditions used.
Notch信号通路在调节造血祖细胞的自我更新和分化中发挥作用。由于急性髓性白血病（AML）起源于造血祖细胞的失调，Notch系统可能参与了异常生长过程。我们之前报道过AML细胞表达Notch蛋白。在本研究中，我们检测了重组人Notch配体蛋白Jagged1和Delta1对原代AML细胞生长和分化的影响。
从12例患者血液中分离出的AML细胞，在包被有Jagged1、Delta1或对照IgG的孔中培养。使用比色法评估短期生长情况。通过集落分析回收的克隆形成细胞来评估自我更新能力，集落分析涉及用配体或对照IgG培养的细胞。通过培养细胞的形态学和流式细胞术分析评估分化情况。
配体刺激在原代AML细胞的短期生长中引起了三种类型的反应，即促进、抑制或无显著影响。即使在显示短期生长促进的细胞中，配体对自我更新能力的影响也是抑制或无显著影响。配体刺激使原始细胞的形态转变为巨噬细胞样细胞，并在一些样本中增加了分化标志物如CD13或CD14的表达。
Notch配体对原代AML细胞的短期生长有多种影响。在所用条件下，这些配体并未促进所检测的任何细胞的自我更新能力，反而倾向于诱导分化。
