Perez Dominique R, Smagley Yelena, Garcia Matthew, Carter Mark B, Evangelisti Annette, Matlawska-Wasowska Ksenia, Winter Stuart S, Sklar Larry A, Chigaev Alexandre
University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, USA.
University of New Mexico Center for Molecular Discovery, Albuquerque, NM, USA.
Oncotarget. 2016 Jun 7;7(23):33960-82. doi: 10.18632/oncotarget.8986.
Apoptotic evasion is a hallmark of cancer. We propose that some cancers may evade cell death by regulating 3'-5'-cyclic adenosine monophosphate (cAMP), which is associated with pro-apoptotic signaling. We hypothesize that leukemic cells possess mechanisms that efflux cAMP from the cytoplasm, thus protecting them from apoptosis. Accordingly, cAMP efflux inhibition should result in: cAMP accumulation, activation of cAMP-dependent downstream signaling, viability loss, and apoptosis. We developed a novel assay to assess cAMP efflux and performed screens to identify inhibitors. In an acute myeloid leukemia (AML) model, several identified compounds reduced cAMP efflux, appropriately modulated pathways that are responsive to cAMP elevation (cAMP-responsive element-binding protein phosphorylation, and deactivation of Very Late Antigen-4 integrin), and induced mitochondrial depolarization and caspase activation. Blocking adenylyl cyclase activity was sufficient to reduce effects of the most potent compounds. These compounds also decreased cAMP efflux and viability of B-lineage acute lymphoblastic leukemia (B-ALL) cell lines and primary patient samples, but not of normal primary peripheral blood mononuclear cells. Our data suggest that cAMP efflux is a functional feature that could be therapeutically targeted in leukemia. Furthermore, because some of the identified drugs are currently used for treating other illnesses, this work creates an opportunity for repurposing.
凋亡逃避是癌症的一个标志。我们提出，一些癌症可能通过调节3'-5'-环磷酸腺苷（cAMP）来逃避细胞死亡，而cAMP与促凋亡信号传导相关。我们假设白血病细胞具有将cAMP从细胞质中排出的机制，从而保护它们免于凋亡。因此，抑制cAMP外排应导致：cAMP积累、cAMP依赖性下游信号激活、活力丧失和凋亡。我们开发了一种新的检测方法来评估cAMP外排，并进行筛选以鉴定抑制剂。在急性髓系白血病（AML）模型中，几种已鉴定的化合物降低了cAMP外排，适当地调节了对cAMP升高有反应的信号通路（cAMP反应元件结合蛋白磷酸化，以及极晚期抗原-4整合素失活），并诱导了线粒体去极化和半胱天冬酶激活。阻断腺苷酸环化酶活性足以降低最有效化合物的作用。这些化合物还降低了B系急性淋巴细胞白血病（B-ALL）细胞系和原发性患者样本的cAMP外排和活力，但对正常原发性外周血单个核细胞没有影响。我们的数据表明，cAMP外排是白血病中一个可作为治疗靶点的功能特性。此外，由于一些已鉴定的药物目前用于治疗其他疾病，这项工作为药物重新利用创造了机会。
