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: 8653055
• 负责人: Andrei Thomas-Tikhonenko
• 金额: $ 14.62万
• 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 2015-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8653055
• 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; 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; Reliance; 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; public health relevance; 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（由申请方提供）：c-Myc原癌基因是B细胞稳态和B淋巴瘤发生的关键因子。其转化潜力主要基于其驱动细胞增殖的能力。同时，Myc也可以诱导细胞凋亡，无论是p53的p53的p53的诱导或在p53非依赖性的方式。然而，迄今为止，将Myc的促凋亡活性引导到抗癌治疗的目标已经被证明是难以捉摸的，主要是因为暂时增加Myc水平的方法不存在。我们最近的研究表明，提高Myc表达会提高p53，并增加对硼替佐米的敏感性。该研究的一个局限性是依赖于p53通路，而p53通路在人类B淋巴瘤中经常丢失。为了确定Myc如何在真正的治疗环境（CHOP治疗）中促进p53非依赖性细胞凋亡，我们现在使用从p53 ERTAM敲入小鼠骨髓中分离的细胞，随后用表达Myc的逆转录病毒转导。这种诱导系统使我们能够区分p53依赖性（用他莫昔芬处理的细胞）和独立性（没有给予他莫昔芬）细胞死亡。此外，我们实验室的最新数据表明，GSK-3 <$积极参与B细胞中Myc蛋白降解的调节，并且CHIR 99021对GSK-3 <$的抑制会显著增加Myc水平。使用这些试剂，我们观察到GSK-3抑制剂对Myc的药理学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突变的拉莫斯伯基特淋巴瘤细胞中，Myc稳定化也导致对阿霉素的反应增加。这些结果完全支持我们的创新假设，即Myc的瞬时上调可能是Myc驱动的肿瘤的可行辅助治疗，即使是p53缺失或MDM 2扩增。我们将在以下两个目标中探讨这一假设。1)研究多柔比星+GSK 3？抑制剂作用下，Myc依赖性和非依赖性事件驱动p53非依赖性细胞凋亡。具体而言，我们将确定Myc的遗传或药理学抑制是否消除了CHIR 99021的促凋亡作用，或者其他GSK-3？靶标如BCL 2L 12是否有助于化学增敏。2)研究GSK 3抑制如何影响伯基特淋巴瘤对阿霉素的急性和慢性治疗模型的反应。根据我们的体外数据，我们将测试GSK-3抑制是否增强基于阿霉素的化疗对小鼠同系移植物和人异种移植物的作用，从而导致更稳健的凋亡反应（急性模型）和延长的无事件生存期（慢性模型）。完成这项工作后，我们将更好地了解GSK 3调节的凋亡途径及其靶点，如Myc和BCL 2L 12。此外，我们还将验证GSK 3抑制剂作为辅助治疗药物，用于治疗突变型p53或MDM 2扩增的Myc驱动的B细胞淋巴瘤。