Strategies to improve the antiglioma action of IFN-?: a role for NF-kB inhibition

描述(申请人提供)：脑瘤是美国癌症相关死亡的主要原因之一，多形性胶质母细胞瘤(GBM)是最具侵袭性和最难治疗的亚型之一。在这项提案中，我们计划寻求一种使用强大的抗肿瘤细胞因子--干扰素-β(IFN2)治疗恶性胶质瘤的策略。I型(1/2)干扰素(IFN)长期以来一直被认为具有显著的多效性抗癌活性。然而，尽管在临床前模型中对包括胶质瘤在内的各种肿瘤类型具有显著的活性，但在临床试验中，IFN的抗肿瘤效果一直令人失望。一个重要的因素包括通过下调凋亡途径对干扰素介导的细胞死亡产生抵抗力。我们已经证实，核因子kB(NFkB)促进细胞存活并抑制干扰素靶基因的表达，这些基因可能是干扰素抗肿瘤活性的效应者。不幸的是，NFkB不仅在包括胶质瘤在内的许多癌症中具有结构性活性，而且还可以被干扰素本身激活。这一发现表明，干扰素的强大抗癌活性可能被NFkB活性所抵消。基于这些观察，我们假设选择性抑制NFkB将增强干扰素的抗癌活性。我们将对NFkB在调节IF2在胶质瘤细胞中的抗癌作用中的作用进行系统和详细的评估。根据所获得的见解，我们将选择和测试应该与干扰素具有协同抗肿瘤活性的补充剂。在体外确认这些药物的协同作用后，我们将测试包括干扰素在内的联合治疗在相关恶性胶质瘤临床前模型中的效果。该项目的首要目标是通过更好地了解干扰素2的S抗胶质瘤作用机制和抗胶质瘤的因素来增加干扰素的抗肿瘤活性。在特定的目标1中，我们将研究NFkB在抑制IF2在胶质瘤中的抗癌活性中的作用。为了验证这一点，我们将在胶质瘤细胞系中确定：1)经典的NF：B途径对结构性和干扰素诱导的NF：B活性的贡献；2)替代的NF：B途径对结构性和干扰素诱导的NF：B活性的贡献；以及3)药物和遗传的NF：B抑制剂对干扰素活性的影响。基于这些发现，我们将在相关的临床前恶性胶质瘤啮齿动物模型中测试临床上可用的NFkB抑制剂对干扰素抗癌活性的影响。在特定的目标2中，我们将表征NFkB在调节干扰素靶基因中的作用，以及这些靶基因在IFN2抗胶质瘤作用中的作用。为了测试这一点，我们将：1)表征这些基因对干扰素的诱导作用；2)确定它们在体外和体内影响干扰素抗癌活性方面的重要性；以及3)通过在相关的恶性胶质瘤临床前模型中测试适当选择的联合治疗的有效性来解释这些发现。公共卫生相关性：在美国，脑瘤是癌症相关死亡的主要原因之一，多形性胶质母细胞瘤(GBM)是最具侵袭性和最难治疗的亚型之一。因此，恶性胶质瘤的治疗是一个重要的临床问题，迫切需要新的治疗策略。在这项提案中，我们计划寻求一种使用强大的抗肿瘤细胞因子--干扰素-β(IFN2)治疗恶性胶质瘤的策略。

DESCRIPTION (provided by applicant): Brain tumors are among the leading causes of cancer-related deaths in the United States, with glioblastoma multiforme (GBM) being one of the most aggressive and difficult subtypes to treat. In this proposal we plan to pursue a strategy to treat malignant glioma with the potent antitumor cytokine, interferon-beta (IFN2). Type I (1/2) interferons (IFNs) have long been recognized for their significant, pleiotropic anticancer activity. However, despite significant activity in preclinical models against a variety of tumor types, including gliomas, the antitumor efficacy of IFNs in clinical trials has been disappointing. A significant contributing factor includes the development of resistance to IFN-mediated cell death through downregulation of apoptotic pathways. We have established that nuclear factor kB (NFkB) promotes cell survival and suppresses the expression of a subset of IFN target genes that are likely effectors of IFN's antitumor activity. Unfortunately, not only is NFkB constitutively active in many cancers, including glioma, but it can also be activated by IFN itself. This finding suggests that the potent anticancer activity of IFN may be counterbalanced by NFkB activity. Based on these observations, we hypothesize that selective inhibition of NFkB will enhance the anticancer activity of IFN. We will perform a systematic and detailed evaluation of the role of NFkB in regulating the anticancer action of IFN2 in glioma cells. Based on the insights gained, we will select and test complementary agents that should provide synergistic antitumor activity with IFN. After confirming the synergy of these agents in vitro, we will test the effectiveness of combination therapy that includes IFN in relevant preclinical models of malignant glioma. The overriding goal of this project is to increase the antitumor activity of IFN through an improved understanding of IFN2's mechanism of action against glioma and the factors that work against it. In specific aim 1 we will examine the role of NFkB in suppressing the anticancer activity of IFN2 in gliomas. To test this, we will determine in glioma cell lines 1) the contribution of the classical NF:B pathway to constitutive and IFN-induced NF:B activity; 2) the contribution of the alternative NF:B pathway to constitutive and IFN-induced NF:B activity; and 3) the effects of pharmacological and genetic NF:B inhibitors on IFN activity. Based on these findings, we will test the effects of clinically available NFkB inhibitors on IFN's anticancer activity in relevant, preclinical rodent models of malignant glioma. In specific aim 2 we will characterize the role of NFkB in regulating IFN target genes and the role of these target genes in the anticancer action of IFN2 in gliomas. To test this, we will: 1) characterize the induction of these genes in response to IFN; 2) determine their importance in effecting the anticancer activity of IFN in vitro and in vivo and 3) translate these findings by testing the efficacy of appropriately selected combination therapy in relevant, preclinical models of malignant glioma. PUBLIC HEALTH RELEVANCE: Brain tumors are among the leading causes of cancer-related deaths in the United States, with glioblastoma multiforme (GBM) being one of the most aggressive and difficult subtypes to treat. Thus, the treatment of malignant glioma is a significant clinical problem for which new strategies are desperately needed. In this proposal we plan to pursue a strategy to treat malignant glioma with the potent antitumor cytokine, interferon beta (IFN2).