PROTEIN KINASE C BASED ANTILEUKEMIC THERAPY

描述：(申请人摘要)本申请的目的 是确定蛋白激酶C(PKC)的激活是否可行 抗白血病治疗的策略。急性髓系白血病(AML)和 骨髓发育不良(MDS)表现为骨髓衰竭 从部分或完全阻断造血细胞的成熟 元素。蛋白激酶C(PKC)家族的钙和 磷脂依赖的丝氨酸苏氨酸激酶起着关键作用 在转导单核细胞参与的细胞外信号中 差异化。佛波酯12-0-十四酰-佛波醇-13- 醋酸酯(TPA)，一种有效的单核细胞成熟诱导剂 谱系，结合并激活PKC。申请人证明了 全反式维甲酸对TPA耐药HL-60细胞的作用 亚系(HL-525)显著增加相对较低的本构关系 在这个变异体中发现了PKCb mRNA和蛋白的水平。ATRA- 介导的PKC活性增加与PKCb基因产物相关 随着以坚持为特征的TPA响应性的获得， 非特异性酯酶染色和c-fms基因表达。他有 证明了Bryostatin 1(一种非促癌化合物，它 在纳摩尔浓度激活PKC)对ATRA-Primed的处理 HL-60和U-937细胞也导致功能显著增强 这些细胞中的单核细胞分化。因此，这种组合 全反式维甲酸和Bryostatin 1可能对以 髓系分化受阻。此应用程序将构建在 申请人通过定义PKC亚型的初步观察(S) 它们被维甲酸严重增加，随后 由TPA或Bryostatin 1激活的几种白血病细胞系和 人白血病细胞(特异靶1)。直接向下游元素 与相关PKC亚型的相互作用将通过以下方式确定 谷胱甘肽-S-转移酶融合结构的构建(特异性目标2)。至 他确保他在白血病细胞系上的发现是可推广的 将测试维甲酸/Bryostatin 1组合对人类 白血病在免疫缺陷小鼠中传播(特定目标3)。最后， 他将在#年进行全反式维甲酸的II期试验 Bryostatin-1联合治疗MDS和难治性AML 将治疗反应与评估生物效应的研究相关联 包括治疗后患者的血清诱导 体外和体内分化(特定目标4)。

DESCRIPTION: (Applicant's Abstract) The objective of this application is to determine whether activation of protein kinase C (PKC) is a viable strategy for anti-leukemic therapy. Acute myeloid leukemia (AML) and myelodysplasia (MDS) are manifested by bone marrow failure resulting from a partial or complete block in maturation of hematopoietic elements. The protein kinase C (PKC) family of calcium and phospholipid-dependent serine-threonine kinases plays a critical role in transducing extracellular signals involved in monocytic differentiation. The phorbol ester 12-0-tetradecanoyl-phorbol-13- acetate (TPA), a potent inducer of maturation along the monocytic lineage, binds to and activates PKC. The applicant demonstrated that all-trans retinoic acid (ATRA) treatment of the TPA-resistant HL-60 cell subline (HL- 525) markedly increases the relatively low constitutive levels of PKCb mRNA and protein found in this variant. The ATRA- mediated increase in PKC activity and PKCb gene product is associated with the acquisition of TPA responsiveness characterized by adherence, non-specific esterase staining, and c-fms gene expression. He has demonstrated that bryostatin 1 (a non-tumor promoting compound which activates PKC at nanomolar concentrations) treatment of ATRA- primed HL-60 and U-937 cells also leads to a marked augmentation of features of monocytic differentiation in these cells. Therefore, the combination of ATRA and bryostatin 1 may be useful in diseases characterized by a block in myeloid differentiation. This application will build upon the applicant's preliminary observations by defining the PKC isoform(s) which are critically increased by retinoic acid and subsequently activated by TPA or bryostatin 1 in several leukemia cell lines and human leukemic cells (Specific Aim 1). Downstream elements directly interacting with the relevant PKC isoform will be determined by means of glutathione-S-transferase fusion constructs (Specific Aim 2). To insure that his findings with leukemic cell lines are generalizable, he will test the retinoic acid/bryostatin 1 combination against human leukemias propagated in immunodeficient mice (Specific Aim 3). Finally, he will conduct a phase II trial of all trans retinoic acid in combination with bryostatin 1 in patients with MDS and refractory AML, correlating therapeutic response with studies to assess biologic effects of therapy including the ability of sera from treated patients to induce differentiation in vitro and in vivo (Specific Aim 4).