Targeting defective necroptosis in colorectal cancer

大多数结直肠癌(CRC)患者对治疗反应不佳。新的代理 改善CRC治疗是当务之急。诱导细胞程序性死亡或凋亡是一个主要效应 抗癌治疗。最近的研究表明，细胞程序性死亡也包括坏死性下垂，这是一种受调控的 受受体相互作用蛋白1(RIP1)、RIP3和混合谱系激酶控制的坏死性死亡形式 结构域样蛋白(MLKL)。越来越多的证据表明，与细胞凋亡类似的坏死性下垂的功能 作为阻止肿瘤发展的屏障，在抗癌治疗中发挥着重要作用。下调监管或 RIP1、RIP3和MLKL的突变在肿瘤中经常被发现，并有助于治疗 抵抗。然而，很少有人尝试以癌细胞中有缺陷的坏死性下垂为靶点。 对坏死性下垂在抗癌治疗中的调节机制和功能作用认识不足。 我们最近的研究发现了一种新的由PUMA、P53靶点和BH3-Only-BH3-2介导的坏死性下垂途径 多种抗癌药物诱导细胞死亡所必需的家族蛋白。这条路可以利用 通过常见的化疗药物，如5-氟尿嘧啶(5-FU)杀死部分CRC细胞。然而，这条路径 由于经常不能从事CRC细胞的RIP3表达丢失，这促使我们寻找 可以恢复RIP3缺陷的CRC细胞中的坏死性下垂的药物。我们的初步数据显示，OSW-1，一种天然的 具有强大的抗癌活性的化合物，激活P53和PUMA以诱导CRC细胞的坏死性下垂。 令人惊讶的是，OSW-1诱导和PUMA介导的坏死性下垂不需要RIP1或RIP3，这表明 一种新的作用机制。重要的是，OSW-1的体内抗肿瘤活性需要用 免疫活性肿瘤模型，提示坏死性下垂引发的抗肿瘤免疫的关键作用。基座 根据这些发现，我们建议使用OSW-1作为化学探针来测试PUMA介导的假设 RIP3非依赖性坏死性下垂通过细胞内源性和免疫学效应有效地对抗结直肠癌。 可以被利用来改进CRC治疗。目的1：OSW-1诱导PUMA介导的机制 目的2：PUMA介导和RIP3非依赖性坏死性下垂在结直肠癌细胞中的作用 OSW-1的肿瘤抑制；以及目标3：诱导PUMA介导的和RIP3非依赖性的坏死性下垂 改进结直肠癌治疗。拟议的研究将描绘出一种新的坏死性下垂途径 OSW-1的抗癌活性。这些研究的完成将为发现新的抗癌药物奠定基础 靶向结直肠癌细胞缺陷性坏死性下垂以增强肿瘤细胞杀伤和抗肿瘤免疫的药物 这可能最终导致改善对结直肠癌和其他癌症的治疗。

Most patients with colorectal cancer (CRC) do not respond well to therapeutic treatment. New agents for improving CRC therapy are urgently needed. Induction of programmed cell death or apoptosis is a major effect of anticancer therapy. Recent studies indicate that programmed cell death also includes necroptosis, a regulated form of necrotic death controlled by Receptor-Interacting Protein 1 (RIP1), RIP3, and Mixed Lineage Kinase Domain-Like protein (MLKL). Accumulating evidence suggests that necroptosis, similar to apoptosis, functions as a barrier against tumor development and plays an important role in anticancer therapy. Downregulation or mutations of RIP1, RIP3, and MLKL have been frequently found in tumors and contribute to therapeutic resistance. However, few attempts have been made to target defective necroptosis in cancer cells due to insufficient understanding of the regulatory mechanism and functional role of necroptosis in anticancer therapy. Our recent studies identified a new necroptosis pathway mediated by PUMA, a p53 target and a BH3-only Bcl-2 family protein that is essential for cell death induced by a variety of anticancer drugs. This pathway can be utilized by common chemotherapeutics such as 5-fluorouracil (5-FU) to kill a subset of CRC cells. However, this pathway often cannot be engaged in CRC cells due to frequent loss of RIP3 expression, which prompted us to search for agents that can restore necroptosis in RIP3-deficient CRC cells. Our preliminary data show that OSW-1, a natural compound with potent anticancer activity, activates p53 and PUMA to induce necroptosis in CRC cells. Surprisingly, OSW-1-induced and PUMA-mediated necroptosis does not require either RIP1 or RIP3, suggesting a novel mechanism of action. Importantly, the in vivo antitumor activity of OSW-1 needs to be characterized using immuno-competent tumor models, suggesting a critical role of necroptosis-triggered antitumor immunity. Based on these findings, we propose to use OSW-1 as a chemical probe to test the hypothesis that PUMA-mediated and RIP3-independent necroptosis is efficacious against CRC via both cell-intrinsic and immunologic effects, and can be exploited to improve CRC therapy. Aim 1: Mechanism by which OSW-1 induces PUMA-mediated necroptosis in RIP3-deficient CRC cells; Aim 2: Role of PUMA-mediated and RIP3-independent necroptosis in tumor suppression by OSW-1; and Aim 3: Induction of PUMA-mediated and RIP3-independent necroptosis for improving CRC therapy. The proposed studies will delineate a novel necroptosis pathway underlying the potent anticancer activity of OSW-1. Completion of these studies will lay a foundation for identifying new anticancer agents that target defective necroptosis in CRC cells to enhance tumor cell killing and antitumor immune response, which may ultimately lead to improved treatment of CRC and other cancers.