Targeting the CaM Kinases in Treating Myeloid Leukemia

描述（由申请人提供）：急性髓性白血病（AML）是由正常骨髓前体细胞/干细胞的终末分化受阻引起的，导致未成熟髓母细胞的潜在致命积累。维甲酸（RA）等药物可以增强某些髓性白血病细胞的终末分化，并在髓性白血病的急性早幼粒细胞白血病（APL）亚群的治疗中具有重要的治疗作用。然而，20-30%的APL患者尽管接受了RA治疗仍会复发，而大多数其他类型的AML对RA完全没有反应。确定调节RA受体活性的因子将有助于了解为什么这些不同的AML细胞对RA的反应不同。我们已经观察到Ca++调节的蛋白激酶（CaM激酶）是RA受体活性和髓系白血病细胞分化的关键调节因子。事实上，作为CaM激酶的一种小分子抑制剂，KN62能够在体外触发某些AML细胞的终末分化。我们的长期目标是确定CaM激酶在调节RA受体活性和髓细胞分化中的分子基础，我们希望将这一知识转化为针对某些人类髓细胞白血病的新型靶向治疗。在Specific Aim I中，我们将确定CaM激酶表达、细胞定位和酶活性在调节对RA和KN62诱导分化敏感的髓系白血病细胞分化中的作用。在Specific Aim II中，我们将探讨CaM激酶的表达，本地化和活动对RA的AML细胞株/ KN62为了生化和分子区分这些麻木不仁的AML细胞敏感细胞株针对性。最后分析了在针对性三世,我们将评估主要的细胞分化响应AML样品在短期内文化RA和KN62并确定是否有任何关联与特定临床病理的或分子参数的响应表现出这些不同的原代AML细胞。

DESCRIPTION (provided by applicant): Acute myelogenous leukemia (AML) results from a block in the terminal differentiation of normal myeloid precursors/stem cells leading to the potentially lethal accumulation of immature myeloblasts. Agents such as retinoic acid (RA) can enhance the terminal differentiation of certain myeloid leukemia cells and have had a major therapeutic impact in the treatment of the acute promyelocytic leukemia (APL) subset of myeloid leukemia. Nevertheless 20-30% of APL patients still relapse despite RA therapy, and most other types of AML fail to respond at all to RA. Defining factors which regulate RA receptor activity will provide insight into why these different AML cells respond differently to RA. We have observed that the Ca++regulated protein kinases (CaM kinases) are critical regulators of both RA receptor activity and myeloid leukemia cell differentiation. Indeed KN62, a small molecule inhibitor of the CaM kinases, triggers the in vitro terminal differentiation of certain AML cells. Our Long Term Objectives are to define the molecular basis for this previously unexplored role of the CaM kinases in regulating RA receptor activity and myeloid differentiation, and we hope to translate this knowledge into novel targeted therapy for certain human myeloid leukemias. In Specific Aim I we will determine the role of CaM kinase expression, cellular localization and enzymatic activity in regulating the differentiation of myeloid leukemia cells that are sensitive to RA and KN62 induced differentiation. In Specific Aim II we will explore CaM kinase expression, localization and activity in AML cell lines that are insensitive to RA/KN62 in an effort to biochemically and molecularly distinguish these insensitive AML cells from the sensitive cell lines analyzed in Specific Aim I. Finally in Specific Aim III we will assess the differentiative response of primary AML samples in short term culture to RA and KN62 and determine whether there is any correlation of their response with the specific clinicopathological or molecular parameters exhibited by these different primary AML cells. Relevance. These studies will dissect a new, previously unexplored role of the CaM kinases in regulating the differentiation of myeloid leukemia cells and are directly relevant for identifying new molecular targets for the clinical therapy of the human myeloid leukemias.