Oxidative stress and programmed death pathways: Cross talk in pancreatic cancer

描述（由申请人提供）：目前针对胰腺癌（PanCA）的治疗方法不足且疗效有限。因此，对于开发选择性靶向肿瘤细胞的新型有效化合物存在巨大的未满足的需求。虽然天然产物被公认为是治疗各种疾病（包括癌症）的药物来源，但很少有研究系统地探讨天然产物在胰腺癌中的潜在预防/治疗益处。我们已经发现了一种名为“NexrutineR”（Nx）的天然化合物，它从黄花蒿树皮中分离出来，可以抑制胰腺癌细胞的生长，并通过产生活性氧（ROS）诱导细胞凋亡和自噬。此外，观察到的细胞毒性作用对肿瘤细胞具有特异性。Nx降低了两种关键的氧化还原调节转录因子的水平和活性，这两种转录因子控制致癌信号传导，即NFκB和Stat 3，导致抗凋亡蛋白FLIP的调节。基于这些观察结果，我们假设Nx含有具有强效抗胰腺癌活性的新型生物活性化合物。我们将检验以下假设：Nx及其生物活性化合物通过一种新机制发挥作用，其中FLIP通过两种氧化还原调节转录因子（Stat 3和NFκB）调节，导致肿瘤细胞特异性程序性细胞死亡的调节。该假设将在以下具体目标中得到解决：1：在一组人胰腺癌细胞系中确定程序性细胞死亡过程和Nx诱导的氧化应激之间的串扰机制; 2：使用胰腺癌的临床前动物模型证明程序性细胞死亡过程和氧化应激之间的串扰的破坏阻断或延迟肿瘤生长; 3：使用细胞培养模型探索巴马汀（Nx的生物活性组分）重演Nx诱导的生物活性的能力; 4：使用胰腺癌的临床前动物模型评估使用巴马汀阻断或延迟肿瘤生长对程序性细胞死亡过程和氧化应激之间的串扰的破坏。Nx在癌细胞中具有抗肿瘤活性，在正常细胞中具有低毒性或无毒性，是一种有前途的药物。这些研究将为开发针对胰腺癌的替代和补充药物策略提供合理的基础。

DESCRIPTION (provided by applicant): Current therapies against pancreatic cancer (PanCA) are inadequate and limited in efficacy. Therefore there is a huge unmet need for development of novel effective compounds that selectively target tumor cells. Although natural products are well recognized as sources of drugs for various diseases including cancer, very few studies systematically explored the role of natural products for their potential preventive/therapeutic benefit in pancreatic cancer. We have discovered a natural compound called "NexrutineR" (Nx) isolated from the bark of Phellodendron amurense that inhibits pancreatic cancer cell growth and induces apoptosis and autophagy through production of reactive oxygen species (ROS). Further the observed cytotoxic effects are specific to tumor cells. Nx decreased levels and activity of two key redox-regulated transcription factors that control oncogenic signaling namely NFκB and Stat3 that results in modulation of anti-apoptotic protein FLIP. Based on these observations we postulate that Nx contains novel bioactive compounds with potent anti-pancreatic cancer activity. We will test the hypothesis that Nx and its bioactive compound works through a novel mechanism in which FLIP regulation by two redox-regulated transcription factors (Stat3 and NFκB) leads to modulation of tumor cell specific programmed cell death. This hypothesis will be addressed in following specific aims: 1: Determine the mechanism of cross talk between programmed cell death processes and Nx-induced oxidative stress ina panel of human pancreatic cancer cell lines; 2: Demonstrate that the disruption of cross talk between programmed cell death processes and oxidative stress blocks or delays tumor growth using preclinical animal models of pancreatic cancer; 3: Explore the ability of Palmatine, a bioactive component of Nx recapitulate Nx-induced biological activities using cell culture models; 4: Evaluate that the disruption of cross talk between programmed cell death processes and oxidative stress using Palmatine blocks or delays tumor growth using preclinical animal models of pancreatic cancer. Nx is a promising agent for its anti-tumorigenic activity in cancer cells wit low to no toxicity in normal cells. These studies will provide a rational basis for developing alternative and complementary medicinal strategies for targeting pancreatic cancer.