A novel therapy for pancreatic neuroendocrine tumors

在过去的两年中，胰腺神经内分泌肿瘤(PNETs)的发病率有所增加。 几十年。局限性PNETs的主要治疗方法是手术切除，但没有有效的方法。 晚期不能切除或转移性疾病的治疗。无进展存活率为 使用FDA批准的药物Everolimus的最佳11个月，而使用安慰剂的4.6个月。然而， 大多数患者会产生耐药性，我们对这种疾病的理解是空白的 PNETs中的耐药机制。MEN1(44%)、DAXX/ATRX(43%)、mTOR(15%)的频繁突变 途径基因和Von Hippel Lindau病(VHL)以及其他几种遗传性疾病是 在PNETs中观察到。VHL的丧失与增强的肿瘤有氧糖酵解(Warburg效应)有关。在……里面 在这种情况下，癌细胞更加严重地依赖于烟酰胺腺嘌呤二核苷酸(NAD)池，这是一个至关重要的 高有氧糖酵解癌细胞代谢途径氧化还原反应中的辅因子。这一切都结束了- 对NAD的依赖可能在NAD挽救途径中提供可行的治疗途径。我们的 PNET细胞株和患者来源组织的初步研究表明VHL调节的NAD被激活 生物合成限速酶烟酰胺磷酸核糖转移酶(NAMPT) MTOR启动子p21激活的蛋白4(PAK4)的表达。PAK4蛋白由于其能够 已经证明，参与多个配体可以调节包括PNET在内的一系列信号通路 抗性分子。PAK4-NAMPT双RNAi显著抑制PNET细胞的增殖。这个 CRISPR/Cas9验证的PAK4-NAMPT双抑制剂KPT-9274(I期药物)显示出抗肿瘤活性 体外，在PNET异种移植瘤中，并能协同增强Everolimus的细胞毒作用。分子分析 联合治疗显示已知的伊波莫司耐药启动子对ATP的抑制作用下调 和NAD。正常细胞可以利用烟酸磷酸核糖转移酶(NAPRT1)，这是一种经常在 启动子甲基化引起的肿瘤)通过烟酸产生NAD。因此，烟酸-co- 治疗可以允许KPT-9274剂量递增，而不会对正常组织产生不必要的毒性。我们假设 靶向PAK4-NAMPT信号通路可能成为治疗PNET的一种广泛且临床可行的治疗策略。 目的：分析PNET患者组织中PAK4和NAMPT的异常。目标2：展示PAK4- NAMPT对PNET治疗耐药。目的3：验证PAK4-NAMPT双抗的临床前体内疗效 PNET异种移植中的抑制物并定义正在进行的活检中治疗反应的生物标志物 第一阶段试验。临床影响：我们的研究将加强对PAK信号和 PNET生存中的NAD代谢。这项工作还将揭示基于他们的理想患者群体 最佳治疗反应的NAPRT状态。我们的临床前研究将导致开发一种新的 为治疗难治和目前为止无法治愈的PNETs量身定做的方案。

The incidence of the pancreatic neuroendocrine tumor (PNETs) has increased over the past two decades. The principal treatment for localized PNETs is surgical resection; however, there is no effective therapy for patients with advanced unresectable or metastatic disease. The progression-free survival rate is at the best 11 months with FDA approved agent Everolimus compared to 4.6 months with the placebo. However, the majority of the patients develop drug resistance and there is a void in our understanding of the mechanisms of resistance in PNETs. Frequent mutations in MEN1 (44%), DAXX/ATRX (43%), mTOR (15%) pathway genes and Von Hippel Lindau disease (VHL) alongside several other hereditary disorders are observed in PNETs. Loss of VHL has been linked to enhanced tumor aerobic glycolysis (Warburg effect). In this scenario, cancer cells rely more heavily on Nicotinamide Adenine Dinucleotide (NAD) pool that is a crucial co-factor in the redox reactions of metabolic pathways of cancer cells with high aerobic glycolysis. This over- dependence on NAD may provide actionable therapeutic avenues within the NAD salvage pathway. Our preliminary studies in PNET cell lines and patient derived tissue demonstrate activation of VHL regulated NAD biosynthesis rate-limiting enzyme Nicotinamide Phosphoribosyltransferase (NAMPT) alongside the over- expression of the mTOR promoter p21 activated kinase 4 (PAK4). PAK4 protein by virtue of its ability to engage multiple ligands has been shown to regulate a repertoire of signaling pathways including PNET resistance molecules. Significantly, PAK4-NAMPT dual RNAi suppressed proliferation in PNET cell lines. The CRISPR/Cas9 validated PAK4-NAMPT dual inhibitor KPT-9274 (a Phase I drug) shows antitumor activity in vitro, in PNET xenograft and could synergistically enhance the cytotoxicity of Everolimus. Molecular analysis of combination treatment showed down-regulation of known Everolimus resistance promoter suppression of ATP and NAD. Normal cells can utilize Nicotinate phosphoribosyltransferase (NAPRT1, an enzyme often absent in tumors due to promoter methylation) to generate NAD through nicotinic acid. Therefore, nicotinic acid co- treatment can allow KPT-9274 dose escalation without undue toxicity to normal tissue. We hypothesize that targeting of PAK4-NAMPT signaling could become a broad and clinically viable therapeutic strategy for PNET. Aim1: Profile the PAK4 and NAMPT aberrations in PNET patient tissue. Aim 2: Demonstrate the role of PAK4- NAMPT in PNET therapy resistance. Aim 3: Demonstrate the preclinical in vivo efficacy of PAK4-NAMPT dual inhibitors in PNET xenograft and define a biomarker of therapeutic response in biopsies from an ongoing Phase I trial. Clinical impact: Our studies will enhance the fundamental understanding of PAK signaling and NAD metabolism in PNET subsistence. This work will also uncover the ideal patient population based on their NAPRT status for best treatment response. Our preclinical studies will lead to the development of a novel tailored regimen for therapy-resistant and by far incurable PNETs.