GSK3 inhibition as an adjuvant therapy for Burkitt's lymphoma

GSK3 抑制作为伯基特淋巴瘤的辅助治疗

• 批准号: 8788701
• 负责人: Andrei Thomas-Tikhonenko
• 金额: $ 25.58万
• 依托单位: CHILDREN'S HOSP OF PHILADELPHIA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8788701
• 关键词: Acute; Adjuvant; Adjuvant Therapy; Affect; Antisense RNA; Apoptosis; Apoptotic; B-Cell Lymphomas; B-Lymphocytes; Blood; Bone Marrow; Bortezomib; Burkitt Lymphoma; Cell Death; Cell Line; Cell Proliferation; Cells; Cessation of life; Chemosensitization; Chronic; Data; Disease-Free Survival; Doxorubicin; Event; Experimental Designs; FDA approved; Feedback; Genetic; Genets; Glycogen Synthase Kinase 3; Goals; Health; Homeostasis; Human; In Vitro; Knock-in Mouse; Life; Lithium; Lithium Chloride; Lymphoma; Lymphomagenesis; MDM2 gene; Malignant Neoplasms; Mental disorders; Methods; MicroRNAs; Modeling; Mus; Mutate; Noxae; Oncogene Proteins; Oncogenes; PMAIP1 gene; Pathway interactions; Patients; Pharmaceutical Preparations; Phase I/II Trial; Preparation; Reagent; Regimen; Regulation; Research; Retroviridae; System; Tamoxifen; Testing; Therapeutic; Time; Up-Regulation; Work; Xenograft procedure; base; c-myc Genes; c-myc Proto-Oncogenes; cancer therapy; chemotherapy; in vivo; inhibitor/antagonist; innovation; large cell Diffuse non-Hodgkin' s lymphoma; mutant; novel; protein degradation; research study; response; rituximab; standard of care; tumor

DESCRIPTION (provided by applicant): The c-Myc proto-oncogene is a key factor in both B-cell homeostasis and B-lymphomagenesis. Its transforming potential is based largely on its ability to drive cell proliferation. At the same time, Myc can also induce apoptosis, either throug induction of p53 or in a p53-independent manner. Yet the goal of channeling the pro-apoptotic activity of Myc toward anti-cancer therapies has so far proven elusive, primarily because methods to transiently increased Myc levels didn't exist. Our recent research showed that boosting Myc expression elevates p53 and increases sensitivity to bortezomib. One limitation of that study was the reliance on the p53 pathway, which is frequently lost in human B-lymphomas. To determine how Myc contributes to p53-independent apoptosis in a bona fide therapeutic setting (CHOP therapy), we now used cells isolated from bone marrows of p53ERTAM knock-in mice and subsequently transduced with a Myc-expressing retrovirus. This inducible system allowed us to distinguish between p53-dependent (cells treated with tamoxifen) and independent (no tamoxifen given) cell deaths. Additionally, very recent data from our lab show that GSK-3¿ is actively involved in the regulation of Myc protein degradation in B-cells, and that inhibition of GSK-3¿ with CHIR99021 sharply increases Myc levels. Using these reagents, we observed that pharmacological stabilization of Myc with GSK-3¿ inhibitors strongly enhanced p53-independent doxorubicin-induced apoptosis. Most importantly, even in p53-mutated Ramos Burkitt's lymphoma cells, Myc stabilization resulted in increased responses to doxorubicin. These results fully support our innovative hypothesis that transient up-regulation of Myc could be a viable adjuvant therapy for Myc-driven tumors even with p53 loss or MDM2 amplification. We will pursue this hypothesis in the following two aims. 1) To investigate Myc-dependent and - independent events that drive p53-independent apoptosis in response to doxorubicin+GSK3¿ inhibitors. Specifically, we will determine whether genetic or pharmacological inhibition of Myc abolishes pro- apoptotic effects of CHIR99021 or whether other GSK-3¿ targets such as BCL2L12 contribute to chemosensitization. 2) To investigate how GSK3¿ inhibition affects Burkitt's lymphoma response to doxorubicin in acute and chronic treatment models. On the strength of our in vitro data, we will test if GSK-3¿ inhibition potentiates doxorubicin-based chemotherapy against murine syngeneic grafts and human xenografts, resulting in a more robust apoptotic response (acute model) and prolonged event- free survival (chronic model). Upon completion of this work we will have a better understanding of the apoptotic pathways regulated by GSK3¿ and its targets such as Myc and BCL2L12. Also, we will validate GSK3¿ inhibitors as adjuvant therapeutics to treat Myc-driven B cell lymphomas with mutant p53 or MDM2 amplification.

描述(由申请人提供)：c-Myc原癌基因是B细胞动态平衡和B淋巴癌发生的关键因素。它的转化潜力在很大程度上取决于它驱动细胞增殖的能力。同时，Myc也可以通过P53的诱导或以非P53非依赖的方式诱导细胞凋亡。然而，到目前为止，将Myc的促凋亡活性引导到抗癌治疗中的目标被证明是难以实现的，主要是因为暂时提高Myc水平的方法还不存在。我们最近的研究表明，促进Myc的表达会提高P53，并增加对Bortezomib的敏感性。这项研究的一个局限性是依赖于p53途径，而这一途径在人类B淋巴瘤中经常缺失。为了确定Myc在真正的治疗环境(CHOP疗法)中如何促进p53非依赖性的细胞凋亡，我们现在使用了从p53ERTAM基因敲除小鼠的骨髓中分离的细胞，然后用Myc表达的逆转录病毒进行转导。这个可诱导的系统使我们能够区分p53依赖的(用他莫昔芬处理的细胞)和独立的(不给予他莫昔芬的)细胞死亡。此外，我们实验室的最新数据显示，GSK-3？积极参与调节B细胞Myc蛋白的降解，用CHIR99021抑制GSK-3？显著增加Myc水平。使用这些试剂，我们观察到GSK-3抑制剂对Myc的药理稳定作用强烈增强了P53非依赖性阿霉素诱导的细胞凋亡。最重要的是，即使在p53突变的Ramos Burkitt淋巴瘤细胞中，Myc的稳定也导致了对阿霉素的反应增加。这些结果充分支持了我们的创新假设，即即使在p53缺失或MDM2扩增的情况下，Myc的瞬时上调也可能成为Myc驱动的肿瘤的可行辅助治疗。我们将在以下两个目标中追求这一假说。1)研究阿霉素+GSK3抑制剂诱导P53非依赖性细胞凋亡的Myc依赖和非依赖事件。具体地说，我们将确定Myc的遗传或药物抑制是否会取消CHIR99021的促凋亡作用，或者其他GSK-3靶点，如Bcl2L12是否有助于化学增敏。2)研究在急性和慢性治疗模型中，GSK3抑制如何影响Burkitt淋巴瘤对阿霉素的反应。根据我们的体外数据，我们将测试抑制GSK-3是否加强了基于阿霉素的化疗对小鼠同基因移植物和人类异种移植物的作用，从而导致更强大的细胞凋亡反应(急性模型)和延长无事件生存(慢性模型)。这项工作完成后，我们将更好地了解GSK3？及其靶点Myc和Bcl2L12调控的细胞凋亡通路。此外，我们将验证GSK3抑制剂作为辅助治疗具有突变的p53或MDM2扩增的Myc驱动的B细胞淋巴瘤的作用。