ANTI-NEOPLASTIC EFFECTS OF GAMMA-SECRETASE INHIBITORS

γ-分泌酶抑制剂的抗肿瘤作用

• 批准号: 7060670
• 负责人: Lucio Miele
• 金额: $ 22.25万
• 依托单位: UNIVERSITY OF MASSACHUSETTS AMHERST
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7060670
• 关键词: T lymphocyte; acute lymphocytic leukemia; antineoplastics; aspartic endopeptidases; cell line; cell surface receptors; disease /disorder model; drug interactions; immunopharmacology; immunosuppressive; laboratory mouse; neoplasm /cancer chemotherapy; neoplasm /cancer genetics; neoplasm /cancer immunology; neoplasm /cancer immunotherapy; neoplasm /cancer pharmacology; neoplasm /cancer vaccine; neoplastic cell; neuropharmacology; nuclear factor kappa beta; protease inhibitor; serine threonine protein kinase; xenotransplantation

Gamma-Secretase is a multi-subunit membrane protease that catalyzes the regulated cleavage of numerous type I membrane proteins. These include Notch receptors, which require gamma-secretase cleavage for activation. Gamma-Secretase inhibitors have been proposed as therapeutic agents in cancers expressing Notch receptors, particularly T-cell acute lymphoblastic leukemia (T-ALL), where frequent activating Notch-1 mutations have been recently discovered. Our laboratory is exploring pharmacological and genetic strategies to inhibit Notch signaling for the treatment of neoplastic disorders. As a part of this effort, in addition to focusing on cancer cell killing mechanisms, we are exploring potential toxicities and strategies to circumvent them. In collaboration with Drs. Osborne and Golde, we have studied Notch signaling in thymocytes and peripheral T-cells and compared it to what we observe in malignant T-cells from T-ALL and in other cancer cells. Evidence indicates that Notch-1 activates NF-KB in thymocytes, peripheral T-cells, leukemic T-cells, murine erythroleukemia cells (MEL), primary keratinocytes (KC), cervical cancer cells and neurons. These observations suggest that Notch-1 triggers a conserved pathway that activates NF-KB. We have determined that this pathway begins with the gamma-secretase-dependent formation of complexes between cleaved Notch-1 and two key protein kinases: IKK and PI3K, resulting in AKT-mediated IKK and NF-KB activation. This implies that drugs that inhibit Notch activation and drugs that inhibit NF-KB may synergize, and our preliminary data support this hypothesis. We will test this model in pharmacological and mechanistic experiments in T-ALL cells, using gamma-secretase inhibitors in combination with proteasome inhibitors and with glucocorticoids, drugs that prevent NF-KB activation or antagonize its effects respectively. In collaboration with Drs. Kast, Osborne and Golde we have determined that gamma-secretase inhibitors block dendritic cell differentiation and T-cell activation. Therefore, it is possible that systemic administration of these drugs will have immunosuppressive effects and compromise the efficacy of cancer vaccines when used together with them. Therefore, it is important to determine the effects of gamma-secretase inhibitors in established cancer vaccine models and identify the best administration regimens for combined chemo-immunotherapy. To address these issues, we have once again teamed up with Drs. Osborne, Golde and Kast. Our Hypothesis is that gamma-secretase inhibitors such as LY411,575 (LY) will have chemotherapeutic effects in T-ALL cells and other Notch-expressing cancer cells in vitro and in vivo, mainly through inhibition of Notch-mediated activation of NF-KB via the new pathway we discovered. We further hypothesize that proteasome inhibitor bortezomib, which blocks NF-KB activation, and glucocorticoids, which antagonize NF-KB and cause Notch-1 degradation, will synergize with LY in T-ALL cells. We postulate that immunosuppressive effects of LY can be circumvented when used together with cervical cancer vaccines by timing its administration after the priming phase of the immune response. To test our hypothesis, we propose the following Specific Aims: 1. To establish if the in vitro effects and mechanism of action of LY alone and in combination with clinically relevant agents in T-ALL cell lines. Mechanistic studies will focus on AKT and NF-KB. 2. To determine the in vivo effects of LY, alone and in combination with clinically relevant chemotherapeutic agents chosen based on mechanism, on xenograft models of T-ALL. 3. To determine the in vivo effects of LY on the immune response against cancer cells, using well-established models of tumor vaccination.

γ-分泌酶是一种多含量膜蛋白酶，可催化许多I型膜蛋白的调节裂解。这些包括Notch受体，这些受体需要γ-分泌酶的裂解才能激活。在表达Notch受体的癌症中，已经提出了γ-分泌酶抑制剂为治疗剂，尤其是T细胞急性淋巴细胞性白血病（T-ALL），最近发现了频繁激活Notch-1突变。我们的实验室正在探索药理学和遗传策略，以抑制缺口信号来治疗肿瘤性疾病。作为这项工作的一部分，除了专注于癌细胞杀死机制外，我们还探索了潜在的毒性和策略来规避它们。与Drs合作。奥斯本（Osborne）和戈德（Golde），我们研究了胸腺细胞和周围T细胞中的Notch信号传导，并将其与我们在T-All和其他癌细胞中的恶性T细胞中观察到的凹口信号传导。证据表明Notch-1激活胸腺细胞，周围T细胞，白血病T细胞，鼠红血球血症细胞（MEL），原发性角质形成细胞（KC），宫颈癌细胞，宫颈癌细胞和神经元中的NF-KB。这些观察结果表明Notch-1会触发激活NF-KB的保守途径。我们已经确定该途径始于裂解Notch-1和两个关键蛋白激酶之间的伽马 - 分泌酶依赖性形成：IKK和PI3K，从而导致Akt介导的IKK和NF-KB激活。这意味着抑制NOTCH激活的药物和抑制NF-KB的药物可能会协同作用，并且我们的初步数据支持这一假设。我们将使用γ-分泌酶抑制剂与蛋白酶体抑制剂以及糖皮质激素，防止NF-KB激活或拮抗其作用的药物，在T-ALL细胞的药理和机械实验中测试该模型。与Drs合作。 Kast，Osborne和Golde我们已经确定γ-分泌酶抑制剂阻止树突状细胞分化和T细胞激活。因此，这些药物的全身给药可能会产生免疫抑制作用，并在与之一起使用时损害癌症疫苗的功效。因此，重要的是确定γ-分泌酶抑制剂在既定的癌症疫苗模型中的影响，并确定合并化学免疫疗法的最佳给药方案。为了解决这些问题，我们再次与Drs合作。奥斯本，戈尔德和卡斯特。 我们的假设是，诸如LY411,575（LY）之类的γ-分泌酶抑制剂将对T-ALL细胞和其他表达Notch的癌细胞在体外和体内具有化学治疗作用，主要是通过抑制Notch介导的NF-KB激活NF-KB的激活。通过我们发现的新途径。我们进一步假设阻断NF-KB激活的蛋白酶体抑制剂硼替佐米，而糖皮质激素会拮抗NF-KB并导致Notch-1降解，它将在T-ALL细胞中与LY协同。我们假设，当与宫颈癌疫苗一起使用后，可以通过对免疫反应的启动阶段进行定时给药时，可以规避LY的免疫抑制作用。 为了检验我们的假设，我们提出了以下特定目的：1。确定单独使用LY和与T-ALL细胞系中临床相关的药物的体外作用和作用机理。机械研究将侧重于AKT和NF-KB。 2。为了确定单独和与基于机制选择的临床相关化学治疗剂的体内效应，在T-ALL的异种移植模型上选择的化学治疗剂。 3。使用公认的肿瘤疫苗模型来确定LY对癌细胞免疫反应的体内影响。