Role of Reactive Oxygen Species in B Lymphoma Fate

描述(申请人提供)：在美国普通人群中，癌症是仅次于心脏病的第二大致死原因，也是儿童非意外死亡的主要原因。淋巴瘤是排名第五的癌症问题。据估计，仅淋巴瘤一项就导致美国每年有超过2.5亿人的寿命过早丧失。与局限性实体瘤不同，白血病和淋巴瘤等血液系统恶性肿瘤是自然扩散的，因此需要进行系统治疗。此外，这两种癌症都因对治疗产生抵抗力而臭名昭著。因此，我们的长期目标是从多个代谢、分子和信号转导的角度更好地了解淋巴瘤生物学，从而最终能够开发出更全面、毒性更低和更成功的治疗策略。几乎所有的肿瘤都改变了生物能量学，并且已经确定PI-3K通过mTOR和线粒体Akt/己糖激酶二聚体部分地调节生物能量学。此外，我们以前已经证明，B细胞受体(BCR)介导的PI-3K/Akt抑制导致了B淋巴瘤的死亡。创新：使用一项新技术，即海马细胞外通量分析仪，我们目前的数据显示，BCR刺激导致淋巴瘤代谢的差异调节。这与活性氧物种(ROS)的急剧变化相对应。糖酵解或氧化呼吸的不同利用与细胞周期的特定阶段以及BCR凋亡反应中关键信号蛋白的调节(如c-Myc、Akt、CDK2和p27Kip1)有关。此外，ROS似乎在淋巴瘤信号转导中发挥着重要而独特的作用，因为我们发现硫醇抗氧化剂使Akt和CDK2失活。重要的是，B细胞受体(BCR)的交联、Akt的调控和细胞呼吸的调控，都导致了铜/锌超氧化物歧化酶(SOD1)蛋白表达的快速丧失，而不是MnSOD(SOD2)或过氧化氢酶(CAT)的表达，这表明SOD1是BCR信号转导的关键靶点。SOD1的缺失与下游的BCR信号事件密切相关，这些信号事件导致ROS诱导、细胞周期改变、生长停滞和细胞凋亡，包括：c-Myc和p27Kip1的调节和Akt的去磷酸化。因此，这些数据提供了强有力的证据，表明来自酶系统和代谢输出的ROS与信号蛋白活性的管理和细胞周期进程密切相关。SOD1似乎是这些过程的中心集成者。影响：更好地了解淋巴瘤的这些基本生化过程最终将有助于我们设计更全面的策略，利用氧化还原生物学、细胞周期和普遍存在的肿瘤异常，如代谢异常，以获得更好的癌症治疗结果。我们的具体目标是：1)研究代谢和酶促产生的ROS对SOD1表达和信号蛋白激活的相互关系；2)确定BCR调控SOD1表达的潜在机制。 公共卫生相关性：在美国，每年新增癌症病例超过100万例，与癌症相关的死亡病例超过50万例。我们发现，在淋巴瘤中，活性氧的诱导、代谢、抗氧化酶SOD1的表达、生物能量学的调节、Akt的激活和细胞周期进展之间存在密切的协同作用。更好地了解淋巴瘤的这些基本生化过程将有助于我们设计更全面的治疗策略，利用ROS和氧化还原生物学、细胞周期和细胞代谢等基本过程来获得更好的癌症治疗结果。

DESCRIPTION (provided by applicant): Cancer is second only to heart disease in causing death in the general American population and it is the major cause of non-accidental death in children. Lymphoma is the 5th ranked cancer problem. Lymphoma alone is estimated to cause the premature loss of over 250,000,000 person-years of life in the U.S. annually. Unlike localized solid tumors, hematological malignancies such as leukemia and lymphoma are naturally disseminated, making systemic treatment necessary. In addition, both cancers are especially notorious for developing resistance to therapy. Therefore, our long-term goals are to better understand lymphoma biology from multiple metabolic, molecular and signal transduction points of view so that ultimately, more comprehensive, less toxic and more successful treatment strategies can be developed. Virtually all tumors have altered bioenergetics and it is firmly established that PI-3K regulates bioenergetics in part, through mTOR and the mitochondrial Akt/hexokinase diad. In addition, we had previously demonstrated that B cell receptor- (BCR) mediated suppression of PI-3K/Akt drives B lymphoma death. Innovation: Using a new technology, the SeaHorse Extracellular Flux Analyzer, our present data show that BCR stimulation leads to differential modulation of lymphoma metabolism. This corresponds to dramatic changes in reactive oxygen species (ROS). Differential utilization of glycolytic or oxidative respiration were linked to specific phases of the cell cycle and to modulation of key signaling proteins in the BCR apoptotic response (e.g. c-Myc, Akt, CDK2 and p27Kip1). In addition, ROS appear to play important and distinct roles in lymphoma signal transduction since we find that thiol antioxidants deactivate Akt and CDK2. Importantly, B cell receptor (BCR) cross-linking, modulation of Akt and manipulation of cellular respiration, all resulted in the rapid loss of Cu/Zn superoxide dismutase (SOD1) protein expression and not MnSOD (SOD2) or catalase, showing that SOD1 is a critical target of BCR signaling. The loss of SOD1 precisely correlated with downstream BCR signaling events that lead to ROS induction, cell cycle changes, growth arrest and apoptosis, including: modulation of c-Myc and p27Kip1 and dephosphorylation of Akt. Hence, together, these data provide strong evidence that ROS derived from enzymatic systems and metabolic output are tightly coupled to the management of signal protein activity and to cell cycle progression. SOD1 seems to be a central integrator of these processes. Impact: A better understanding of these basic biochemical processes in lymphoma will ultimately help us to design more comprehensive strategies that exploit RedOx biology, the cell cycle and a universal tumor anomaly such as altered metabolism, to obtain better cancer treatment outcomes. Our specific aims are to: 1), examine the inter-relationships of metabolically and enzymatically-derived ROS on SOD1 expression and signal protein activation and 2), to determine the underlying mechanism regulating BCR-modulated SOD1 expression. PUBLIC HEALTH RELEVANCE: In the United States, there are over 1,000,000 new cancer cases and more than 500,000 cancer-related deaths annually. We have found close cooperation between reactive oxygen species induction, metabolism, expression of the antioxidant enzyme, SOD1, regulation of bioenergetics, activation of Akt and cell cycle progression in lymphoma. A better understanding of these basic biochemical processes first in lymphoma will help us to design more comprehensive treatment strategies that exploit ROS and RedOx biology, the cell cycle and a fundamental process like cellular metabolism, to obtain better cancer treatment outcomes.