Optimizing demethylating therapy for IDH1 Mutant Malignant Gliomas

异柠檬酸脱氢酶1（IDH 1）的驱动突变存在于70-80%的II级和III级胶质瘤中， 大多数最终进展为多形性胶质母细胞瘤（GBM）。在这类分子上不同的 在恶性神经胶质瘤中，突变的IDH 1酶产生2-羟基戊二酸（2-HG），这是一种肿瘤代谢物， α-酮戊二酸依赖性组蛋白和DNA去甲基化酶导致特征性的 基因组DNA和抑制细胞分化。我们已经证明了临床前疗效， 批准的DNA去甲基化药物5-氮杂胞苷（5-Aza）的作用机制和揭示的组合 这进一步提高了生存率。在具有天然IDH 1突变的模型中，5-Aza给药减少了肿瘤细胞的生长。 负荷，延长存活并诱导体内分化。5-Aza与标准护理的组合， 分化和促凋亡药物都显示出进一步的益处。此次修订补助金的重点是优化 针对II级或高级别IDH 1突变胶质瘤的治疗和验证机制。 在目的1中，我们提出了证明5-氮杂诱导的细胞生长减少的机制，并进一步 优化5-Aza与IDH 1突变胶质瘤的标准护理治疗。我们最近展示了 在我们的IDH 1突变体PDX模型中，当使用5-aza时， 与替莫唑胺组合，无论给药顺序如何。在目标2中，我们将确定 DNA去甲基化剂联合维甲酸诱导分化治疗IDH 1突变型胶质瘤。 我们的初步数据表明，5-氮杂调节视黄酸信号，并在IDH 1突变PDX胶质瘤模型， 两者协同作用以减缓肿瘤生长。在目标3中，我们建议将联合收割机5-Aza与促凋亡剂 药物PAC-1在IDH 1突变型胶质瘤中的作用及机制探讨。初步数据表明 半胱氨酸天冬氨酸蛋白酶原激活化合物-1（PAC-1），一种新的脑渗透剂半胱氨酸天冬氨酸蛋白酶原3切割小分子， 在IDH 1突变型胶质瘤的颅内模型中起增加细胞凋亡和存活的作用。我们的统一 对于这些目标中的每一个的假设是，逆转病理学的机制的组合， 去甲基化将增强已知的DNA损伤、细胞衰老和/或衰老的抗癌机制。 细胞凋亡，相互依赖的机制将联合收割机安全地增加存活。 在临床前研究中，提出的每种小分子疗法都显示出单药疗效的证据 神经胶质瘤我们建议确定去甲基化，分化治疗和半胱天冬酶 3激活最好联合收割机安全地用于治疗反应。我们的主要目标是产生临床前数据 这可能会支持一项针对IDH 1突变型胶质瘤患者的新试验。这些疗法有可能导致 DNA损伤将保留用于高级别胶质瘤，而低级别胶质瘤则建议采用毒性较小的治疗方法。 神经胶质瘤，其中存在对生存益处的较大影响的可能性。

Driver mutations in Isocitrate Dehydrogenase 1 (IDH1) are present in 70-80% of grade II and III gliomas, with the majority eventually progressing to glioblastoma multiforme (GBM). In this molecularly distinct class of malignant gliomas, mutant IDH1 enzyme produces 2-hydroxyglutarate (2-HG), an oncometabolite that inhibits α-ketoglutarate dependent histone and DNA demethylases resulting in characteristic hypermethylation of genomic DNA and suppression of cellular differentiation. We have demonstrated the preclinical efficacy and mechanism of action of the approved DNA demethylating drug 5-Azacytidine (5-Aza) and revealed combinations that further enhance survival. In models with the native IDH1 mutation, 5-Aza administration reduces tumor burden, extends survival and induce differentiation in vivo. Combination of 5-Aza with standard of care, use of differentiation, and pro-apoptotic drugs all show further benefit. The focus of this revised grant is to optimize treatment and validate mechanism tailored to either grade II or high grade IDH1 mutant gliomas. In Aim 1 we propose to demonstrate the mechanism of 5-Aza induced cell growth reduction and further optimize 5-Aza with standard of care treatment for IDH1 mutant glioma. We have recently demonstrated reduction in tumor burden and extend survival in our IDH1 mutant PDX model works better when using 5-aza in combination with temozolomide regardless of the order of administration. In Aim 2 we will determine the impact of DNA demethylating agent in combination with differentiation therapy using retinoic acid in IDH1 mutant glioma. Our preliminary data shows that 5-Aza regulates retinoic acid signaling, and in IDH1 mutant PDX glioma model the two work synergistically to slow tumor growth. In aim 3 we propose to combine 5-Aza with the proapoptotic drug PAC-1 in IDH1 mutant glioma and explore the mechanism of response. Preliminary data indicate that Procaspase Activating Compound-1 (PAC-1), a novel brain penetrant procaspase 3 cleaving small molecule, functions to increase apoptosis and survival in an intracranial model of IDH1 mutant glioma. Our unifying hypothesis for each of these aims is that the combination of the mechanisms of reversing pathological demethylation will enhance known anticancer mechanisms of DNA damage, cellular senescence and/or apoptosis, and that interdependent mechanisms will combine to safely increase survival. Each of the small molecule therapies proposed show evidence of single agent efficacy in preclinical studies for glioma. We propose to determine how the mechanisms of demethylation, differentiation therapy and caspase 3 activation best combine safely for a therapeutic response. Our major goal is to produce the preclinical data that might support a new trial for patients with IDH1 mutant glioma. Those therapies with the possibility of causing DNA damage will be reserved for high grade gliomas, while less toxic therapies are proposed for low grade gliomas, where there is the possibility of a large impact on survival benefit.