THE ROLE OF C AMP IN LEUKEMIC CELL DIFFERENTIATION

环磷酸腺苷在细胞增殖和分化中的重要作用 被描述得很好。视黄酸（RA），霍乱毒素 (CT)或8-Br环AMP（8-BrcAMP）对人早幼粒细胞白血病细胞的作用 细胞系（HL 60）的细胞在培养物中导致细胞的显著分化， 成熟的骨髓表型，而添加佛波醇二酯 12-0-十四酰基佛波醇-13-乙酸酯（TPA）导致分化 转化为巨噬细胞 我们检测到cAMP依赖性和 特异性内源性蛋白质的非依赖性磷酸化改变 在RA-1和TPA诱导的HL 60细胞分化过程中， 对每种分化途径都有特异性。 我们注意到了显著的变化 cAMP依赖性和非依赖性蛋白激酶活性， 不同的细胞分化沿着巨噬细胞途径从那些 分化为成熟的髓样表型。 视黄酸和药剂 提高细胞内cAMP协同诱导髓样 分化 我们最近证明，添加低 二甲基甲酰胺、视黄酸、放线菌素D或次黄嘌呤水平 在加入8-溴-环腺苷3之前1-51，单磷酸盐， 霍乱毒素或磷酸二酯酶抑制剂异丁基甲基黄嘌呤， 导致HL 60和HL 60的分化显著增强， RDFD-白血病细胞，表现为获得OKM-1抗原， 减少氮蓝四唑的能力或 趋化性受体 这些结果进一步表明cAMP在 髓样分化 蛋白质无显著调节 在HL 60期间，在胞质组分中检测到磷酸化 暴露于RA或AA和环AMP升高剂。 我们将调查 cAMP依赖性和非依赖性蛋白磷酸化的调节 质膜部分，并确定这些磷酸化是否也 在体内磷酸化过程中， 32PO4.此外，本发明还提供了一种方法， 已从急性髓细胞性白血病患者中分离出原始细胞型， 白血病、急性粒单核细胞白血病、慢性粒单核细胞白血病 和急性淋巴细胞白血病。 这些细胞将暴露于RA， 测定不同时间段和体内蛋白磷酸化。 它 希望对这种分化的生化过程的理解 将使我们能够改善目前的临床治疗。 （百万）

The crucial role of cyclic AMP in cell proliferation and differentiation has been well-described. The addition of retinoic acid (RA), cholera toxin (CT), or 8-Br cyclic AMP (8-BrcAMP) to a human promyelocytic leukemia cell line (HL60) in culture results in a marked differentiation of the cells to a mature myeloid phenotype, while the addition of the phorbol diester 12-0-tetradecanoyl phorbol-13-acetate (TPA) results in the differentiation of the cells into macrophages. We have detected cAMP-dependent and -independent altered phosphorylations of specific endogenous proteins during RA-\and TPA-induced differentiation of HL60 cells which appear to be specific for each pathway of differentiation. We have noted marked changes in the cAMP-dependent and -independent protein kinase activities which are different in cells differentiated along the macrophage pathway from those differentiated to the mature myeloid phenotype. Retinoic acid and agents raising intracellular cyclic AMP synergistically induced myeloid differentiation. We have recently demonstrated that the addition of low levels of dimethyl formamide, retinoic acid, actinomycin D or hypoxanthine prior to the addition of 8-bromo-cyclic adenosine 31-51, monophosphate, cholera toxin or the phosphodisterase inhibitor isobutylmethyl-xanthine, results in marked potentiation of differentiation of both HL60 and the RDFD-leukemic cells as manifested by the acquisition of the OKM-1 antigen, the ability to reduce nitroblue tetrazolium or expression of the chemotactic receptor. These results further suggest a role for cAMP in myeloid differentiation. No significant modulations of protein phosphorylations have been detected in the cytosolic fraction during HL60 exposure to RA or AA and cyclic AMP elevating agents. We will investigate modulation of cAMP-dependent and -independent protein phosphorylations in plasma membrane fractions and determine if these phosphorylations are also noted during in vivo phosphorylation utilizing 32PO4. In addition, blast forms have been isolated from patients with acute myelogenous leukemia, acute myelomonocytic leukemia, chronic myelomonocytic leukemia and acute lymphocytic leukemia. These cells will be exposed to RA for various periods of time and in vivo protein phosphorylation determined. It is hoped that understanding of this biochemical process of differentiation will allow us to improve current clinical treatments. (M)