Molecular Mechanisms in the Treatment of Neuroblastoma

描述(申请人提供)：神经母细胞瘤(NB)是儿童最常见的恶性交感神经系统肿瘤，起源于神经脊。尽管目前积极的治疗策略采用强化清髓化疗和自体骨髓移植，但大多数高危(4期)NB患者死于他们的疾病。为了改善这种疾病患者的预后，必须更好地了解治疗失败的基础以及NB细胞对化疗成功反应的机制。我们工作的主要目标是研究NB中细胞死亡的调节。有两个假设是我们调查的核心。其一是细胞凋亡缺陷在本病的发病机制中起重要作用。第二，可以在了解脑瘤死亡机制是如何有效发挥作用的基础上开发治疗方法。在目前的提案中，我们概述了一些研究，以扩展我们对控制NB中细胞凋亡的治疗调节的信号通路的理解。特别强调多柔比星(Dox)和依托泊苷(VP16)激活的信号转导。DOX和VP16目前用于所有针对NB的有效治疗方案。这项工作的方向是由最近的研究结果指导的，这些结果表明，在Dox杀死某些N型NB细胞时需要NF-kappaB的激活，而在具有代表性的S型细胞系中，NF-kappaB的激活是结构性的，支持细胞的生存。拟议中的实验将确定这些核因子-kappaB活性的差异是否从根本上与S表型或N表型分化有关。此外，我们将研究原发的NB肿瘤，以表征直接在人类肿瘤组织中的NF-kappaB活性。我们将定义介导Dox和VP16诱导的NF-kappaB反应的细胞机制，并使用异种移植模型验证NF-kB调控对Dox治疗的反应的预测。这些目标的结果将有助于理解如何选择其他药物来获得治疗优势(例如，更接近导致NFKappaB活性的途径的分子)，这取决于疾病细胞中的NF-kappaB功能。最后，我们将在原则验证实验中应用在上一次资助期间获得的关于NB细胞对含有促凋亡的BH3蛋白的易感性的具体知识，从而开发一种新的基于疾病选择性多肽的治疗方法。

DESCRIPTION (provided by applicant): Neuroblastoma (NB), the most common malignant sympathetic nervous system tumor of childhood, arises from the neural crest. Despite current aggressive treatment strategies employing intensive myeloablative chemotherapy with autologous bone marrow transplantation, most patients with high risk (Stage 4) NB die of their disease. In order to improve the outcome for patients with this disease, the basis for treatment failures as well as mechanisms that underlie successful responses to chemotherapy in NB cells must be better understood. The primary objective of our work has been to study the regulation of cell death in NB. Two hypotheses are central to our investigation. The first is that defects in apoptosis are essential for the pathogenesis of this disease. The second is that treatments can be developed based on understanding how the death machinery in NB is effectively engaged. In the current proposal we outline studies to extend our understanding of the signaling pathways controlling the therapeutic regulation of apoptosis in NB. A particular emphasis is placed on signaling activated by Doxorubicin (Dox) and etoposide (VP16). Dox and VP16 are presently used in all active treatment protocols for NB. The direction for this work is guided by recent results showing both that NF-kappa:B activation is required for Dox to kill certain N-type NB cells while in representative S-type cell lines NF-KappaB activation is constitutive, supporting cell survival. Proposed experiments will determine whether these differences in NF-kappa B activity are fundamentally linked with S- or N-phenotypic differentiation. Moreover, we will study primary NB tumors to characterize NF-KappaB activity directly in human tumor tissue. We will define the cellular mechanisms that mediate the Dox and VP16-induced NF- kappaB response and verify the prediction that NF-KB governs the response to Dox therapy using xenograft models. The results from these objectives will lead to an understanding of how additional agents could be selected to gain therapeutic advantage (e.g. molecules that more proximally target the pathway causing NFKappaB activity) depending on NF-KappaB function in the diseased cells. Lastly, we will apply specific knowledge acquired during the last funding period pertaining to the susceptibility of NB cells to pro-apoptotic BH3 containing proteins in proof-of-principle experiments leading towards the development of a novel disease selective peptide-based treatment.