Targeting the CaM Kinase Cascade in Treating Myeloid Leukemia

描述(申请人提供)：急性髓系白血病(AML)是由于正常髓系前体/干细胞的终末分化受阻而导致未成熟成髓细胞的潜在致死性堆积所致。维甲酸(RA)等药物可以促进某些髓系白血病细胞的终末分化，并在治疗急性早幼粒细胞白血病(APL)亚群的髓系白血病中发挥了重要的治疗作用。然而，尽管接受了RA治疗，20-30%的APL患者仍然复发，而大多数其他类型的AML对RA完全没有反应。确定调节RA受体活性的因素将有助于深入了解为什么这些不同的AML细胞对RA的反应不同。我们观察到，钙调节蛋白激酶(CaM)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，KN62，一种小分子的CaM激酶抑制剂，触发了某些AML细胞的体外终末分化。我们的长期目标是确定CaM激酶在调节RA受体活性和髓系分化中这一先前未知的作用的分子基础，我们希望将这一知识转化为针对某些人类髓系白血病的新的靶向治疗。在特定的目的I中，我们将确定CaM激酶的表达、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。在特定目标II中，我们将探索CaM激酶在对RA/KN62不敏感的AML细胞系中的表达、定位和活性，以努力从生化和分子水平上区分这些不敏感的AML细胞和在特定目标I中分析的敏感细胞系。最后，在特定目标III中，我们将评估原代AML样本在短期培养中对RA和KN62的分化反应，并确定它们的反应是否与这些不同的原代AML细胞表现出的特定临床病理或分子参数有任何相关性。 关联性。这些研究将剖析CaM激酶在调节髓系白血病细胞分化中的一个新的、以前未被探索的作用，并将直接与确定人类髓系白血病临床治疗的新分子靶点相关。

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.