The Role of Ceramidases in Cancer Chemotherapy

神经酰胺酶在癌症化疗中的作用

• 批准号: 8221194
• 负责人: CUNGUI MAO
• 金额: $ 32.58万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-13 至 2017-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8221194
• 关键词: Animal Model; Apoptosis; Attenuated; Breast Cancer Cell; Cancer cell line; Cell Cycle Arrest; Cell Cycle Progression; Cell membrane; Cells; Ceramidase; Ceramides; Chemotherapy-Oncologic Procedure; Cisplatin; Data; Development; Doxorubicin; Drug resistance; Endoplasmic Reticulum; Enzymes; Etoposide; Future; Generations; Goals; Golgi Apparatus; Hela Cells; Human; Hydrolysis; In Vitro; Inhibition of Apoptosis; Lipids; MDA MB 231; Malignant Neoplasms; Mammalian Cell; Mediating; Mediator of activation protein; Mitotic; Pathway interactions; Pharmaceutical Preparations; Phase; Proteins; Publishing; Role; Sphingolipids; Sphingomyelinase; Sphingosine; TNF gene; Testing; Therapeutic; United States; base; cancer cell; cancer prevention; cancer therapy; chemotherapeutic agent; chemotherapy; cytokine; cytotoxicity; galactosylgalactosylglucosylceramidase; gemcitabine; insight; killings; knock-down; neoplastic cell; novel; novel strategies; response; senescence

DESCRIPTION (provided by applicant): Our long-term goal is to define the mechanisms by which anti-cancer chemotherapeutic agents (ACCAs) induce anti-proliferative responses (proliferation inhibition and programmed cell death) in tumor cells by focusing on human alkaline ceramidase 2 (ACER2) and its lipid substrate (ceramide) and product (sphingosine). Many ACCAs induce the generation of the bioactive sphingolipid ceramide in tumor cells, and blocking ceramide generation inhibits anti-proliferative effects of the drugs, suggesting that ceramide is an important mediator of ACCAs in this anti-proliferative response. Ceramide can be hydrolyzed into sphingosine by ceramidases in human cells and, like ceramide, SPH can potently induce anti-proliferative effects in tumor cells both in vitro and in animal models. Increasing expression of neutral ceramidase ASAH2 on the plasma membrane also attenuates cell apoptosis induced by TNF-1, a known ceramide-generating cytokine. In contrast, our preliminary studies show that increasing the conversion of ceramide to SPH by the Golgi alkaline ceramidase 2 (ACER2) markedly enhances the cytotoxicity of doxorubicin, a known ceramide-inducing ACCA, in HeLa cells, whereas knocking down ACER2 has the opposite effect. This exciting finding led us to the hypotheses that ACCAs exert anti-proliferative responses in cancer cells through the ceramide/ACER2/SPH pathway and that activation of this pathway will augment chemotherapy action in cancer treatment. To test this hypothesis, we will establish that the ceramide/ACER2/SPH pathway is an important mediator of the anti- proliferative responses of ACCAs in cancer cells by determining 1) if ACCAs induce the anti-proliferative responses in cancer cells by activating the ceramide/ACER2/SPH pathway; 2) if ACER2-inducing agents enhance whereas ACER2-inhibiting agents attenuate the ACCA-induced anti-proliferative effects in cancer cells (Aim 1). In Aim 2, we will test the hypothesis that its Golgi localization is required for ACER2 to mediate the ACCA-induced anti-proliferative responses in cancer cells by investigating 1) if targeting ACER2 to the endoplasmic reticulum (ER) abolishes its ability to mediate the ACCA-induced anti-proliferative effects in tumor cells; and 2) if targeting ASAH2 to the Golgi complex confers the ability to mediate ACCA-induced anti- proliferative effects in tumor cells. For Aim 3, we will test the hypothesis that the activation of the ACER2/SPH pathway enhances anti-proliferative responses of ACCAs in tumor cells through Golgi fragmentation. We will determine 1) if ACCAs induces Golgi fragmentation by activating the ceramide/ACER2/SPH pathway; 2) if SPH induces Golgi fragmentation and inhibits Golgi reassembly in vitro; 3) if activating the ceramide/ACER2/SPH inhibits Golgi assembly by inhibiting the stacking function of GRASP65 (Golgi reassembly stacking protein of 65 kD) and GRASP55; and 4) if activation of the ceramide/ACER2/SPH pathway induces mitotic arrest and apoptosis through Golgi fragmentation. These studies will provide insights into the role and mechanism of action of ACER2 and its product SPH in mediating anti-proliferative responses in cancer cells. PUBLIC HEALTH RELEVANCE: Approximately 1500 people die each day in the United States due to cancer. Therefore, better strategies for cancer treatment are necessary. PI's group and others have demonstrated that a group of lipids called sphingolipids, especially, ceramide and sphingosine (SPH), which are found in human cells, can potently kill tumor cells. The PI's group has identified a human enzyme called alkaline ceramidase 2 (ACER2) responsible for the generation of SPH from ceramide in tumor cells. The PI's group finds that increasing ACER2 expression substantially augments the efficacy of doxorubicin, a ceramide-inducing chemotherapeutic agent, in killing cancer cells by increasing the generation of SPH cancer cells. The PI's group is investigating whether and how increasing ACER2 expression also enhances the efficacy of other chemotherapeutic agents against cancer cells. Based on this study, the PI hopes to develop novel approaches for cancer treatment.

描述（由申请人提供）：我们的长期目标是通过关注人碱性神经酰胺酶2（ACER2）及其脂质底物（神经酰胺）和产物（鞘氨醇）来确定抗癌化疗药物（ACCA）在肿瘤细胞中诱导抗增殖反应（增殖抑制和程序性细胞死亡）的机制。许多 ACCA 会诱导肿瘤细胞中生物活性鞘脂神经酰胺的产生，而阻断神经酰胺的产生会抑制药物的抗增殖作用，这表明神经酰胺是 ACCA 抗增殖反应中的重要介质。神经酰胺可被人体细胞中的神经酰胺酶水解为鞘氨醇，并且与神经酰胺一样，SPH 可以在体外和动物模型中有效诱导肿瘤细胞的抗增殖作用。质膜上中性神经酰胺酶 ASAH2 表达的增加也会减弱 TNF-1（一种已知的神经酰胺生成细胞因子）诱导的细胞凋亡。相比之下，我们的初步研究表明，通过高尔基体碱性神经酰胺酶 2 (ACER2) 增加神经酰胺向 SPH 的转化，可显着增强 HeLa 细胞中多柔比星（一种已知的神经酰胺诱导 ACCA）的细胞毒性，而敲除 ACER2 则具有相反的效果。这一令人兴奋的发现使我们得出这样的假设：ACCA 通过神经酰胺/ACER2/SPH 途径在癌细胞中发挥抗增殖反应，并且该途径的激活将增强癌症治疗中的化疗作用。为了检验这一假设，我们将确定神经酰胺/ACER2/SPH 途径是癌细胞中 ACCA 抗增殖反应的重要介质，方法是确定：1​​) ACCA 是否通过激活神经酰胺/ACER2/SPH 途径诱导癌细胞中的抗增殖反应； 2) ACER2 诱导剂是否增强 ACCA 诱导的癌细胞抗增殖作用，而 ACER2 抑制剂减弱 ACCA 诱导的抗增殖作用（目标 1）。在目标 2 中，我们将测试以下假设：ACER2 需要高尔基体定位来介导 ACCA 诱导的癌细胞抗增殖反应，方法是：1) 将 ACER2 靶向内质网 (ER) 是否会消除其介导 ACCA 诱导的肿瘤细胞抗增殖作用的能力； 2)如果将ASAH2靶向高尔基复合体赋予在肿瘤细胞中介导ACCA诱导的抗增殖作用的能力。对于目标 3，我们将测试以下假设：ACER2/SPH 通路的激活通过高尔基体断裂增强肿瘤细胞中 ACCA 的抗增殖反应。我们将确定 1) ACCA 是否通过激活神经酰胺/ACER2/SPH 途径诱导高尔基体断裂； 2) SPH是否在体外诱导高尔基体断裂并抑制高尔基体重组； 3)如果激活神经酰胺/ACER2/SPH通过抑制GRASP65(65kD的高尔基体重组装堆积蛋白)和GRASP55的堆积功能来抑制高尔基体组装； 4) 神经酰胺/ACER2/SPH 通路的激活是否通过高尔基体断裂诱导有丝分裂停滞和细胞凋亡。这些研究将深入了解 ACER2 及其产物 SPH 在介导癌细胞抗增殖反应中的作用和作用机制。 公共卫生相关性：在美国，每天约有 1500 人死于癌症。因此，需要更好的癌症治疗策略。 PI的研究小组和其他人已经证明，人类细胞中存在的一组称为鞘脂的脂质，特别是神经酰胺和鞘氨醇（SPH），可以有效杀死肿瘤细胞。 PI 的研究小组已经鉴定出一种称为碱性神经酰胺酶 2 (ACER2) 的人类酶，负责从肿瘤细胞中的神经酰胺生成 SPH。 PI 的研究小组发现，增加 ACER2 的表达可以显着增强阿霉素（一种神经酰胺诱导化疗剂）通过增加 SPH 癌细胞的生成来杀死癌细胞的功效。 PI 的小组正在研究增加 ACER2 表达是否以及如何增强其他化疗药物对抗癌细胞的功效。基于这项研究，PI 希望开发新的癌症治疗方法。