Acidic Phospholipid-Selective Treatment for Neuroblastoma

描述(由申请人提供)：我们的研究目标是开发一种新的、强大的治疗剂，寻找并摧毁人类神经母细胞瘤。神经母细胞瘤是婴幼儿最常见的癌症。高危神经母细胞瘤即使用最积极的联合或多模式治疗也很难治愈。我们的初步研究表明，使用新的Protelipid纳米微囊以最小的副作用靶向和治疗神经母细胞瘤是可行的。该纳米胶囊由小融合溶酶体蛋白SapC(SapC)和磷脂二油酰磷脂酰丝氨酸(DOPS)组成。这种稳定形成的SapC-DOPS纳米微囊对暴露在癌细胞和新生细胞表面的磷脂酰丝氨酸(PS)具有优先亲和力。我们已经证明，纳米囊泡在神经母细胞瘤肿瘤中有很高的蓄积倾向，并诱导癌细胞凋亡。在神经母细胞瘤动物体内反复注射SapC-DOPS，我们观察到通过酸性鞘磷脂酶神经酰胺介导的信号通路诱导癌细胞凋亡而对肿瘤生长有显著的抑制作用。本提案的目的是确定SapC-DOPS纳米微囊在神经母细胞瘤治疗中的应用。其具体目的是(1)确定人神经母细胞瘤细胞表面PS水平与SapC-DOPS纳米囊靶向和细胞毒反应的关系；(2)开发一种特异性促进人神经母细胞瘤表面PS暴露的增敏剂；(3)通过神经酰胺介导的线粒体为中心的信号通路，阐明SapC-DOPS诱导神经母细胞瘤细胞凋亡的分子机制。这项研究具有创新性，因为SapC-DOPS纳米微囊为寻找和治疗神经母细胞瘤以及其他暴露在细胞表面的PS肿瘤提供了一种独特的方法。这项拟议研究的成功完成将对癌症临床研究领域产生重大影响，因为它为癌症治疗提供了一种安全和广泛的临床方法。 公共卫生相关性：神经母细胞瘤是一种颅外实体癌，最常发生在婴儿期和儿童期。目前高危神经母细胞瘤的治疗方法包括手术、放疗和多模式化疗，但在显著提高生存率方面效果不佳。迫切需要有效的治疗方法。我们正在创造一种治疗神经母细胞瘤的新药物。我们的新方法是使用蛋白质-脂质纳米囊，这种纳米囊可以优先寻找癌症，并在不损害正常细胞的情况下选择性地摧毁肿瘤细胞。我们正在利用人神经母细胞瘤细胞和动物模型来研究纳米囊泡的肿瘤选择性靶向和杀伤机制。拟议研究的成功将使我们能够在人体上测试该产品。

DESCRIPTION (provided by applicant): Our research goal is to develop a new, robust therapeutic agent that seeks and destroys human neuroblastoma. Neuroblastoma is the most common cancer in infancy and children. High-risk neuroblastomas are difficult to cure even with the most aggressive of combination or multi-modal therapies. Our preliminary studies suggest the feasibility of using new protelipid nanovesicles to target and treat neuroblastomas with minimal side effects. The nanovesicle is consisted of the small fusogenic lysosomal protein saposin C (SapC) and the phospholipid dioleoylphosphatidylserine (DOPS). This stably formed SapC-DOPS nanovesicle has preferential affinity for phosphatidylserine (PS) exposed on the surface of cancer cells and neovessels. We have shown that the nanovesicles have high propensity to accumulate in neuroblastoma tumors, and induces apoptosis in the cancer cells. Upon repeated SapC-DOPS injection in neuroblastoma-bearing animals, we observed a significantly inhibitory effect on tumor growth by inducing apoptotic cancer cell death via acid sphingomyelinase-derived ceramide-mediated signaling pathways. The objective in this proposal is to determine SapC-DOPS nanovesicles for their application in treating neuroblastomas. The specific aims are to (1) determine the relationship of cell surface PS levels of human neuroblastoma cells and the targeting and cytotoxic responses to SapC-DOPS nanovesicles, (2) develop a SapC-DOPS sensitization agent that specifically promotes the PS exposure on the surface of human neuroblastoma, and (3) delineate the molecular mechanism underlying SapC-DOPS induced apoptotic cell death of human neuroblastoma via the ceramide-mediated mitochondria-centric signaling pathway. This research is innovative because SapC-DOPS nanovesicles offer a unique approach for seeking and treating neuroblastomas, as well as other tumors with cell surface exposed PS. The successfully completion of the proposed research will have a major impact on the field of cancer clinical research, since it provides a safe and broad clinical approach for cancer therapy. PUBLIC HEALTH RELEVANCE: Neuroblastoma is an extracranial solid cancer that most commonly occurs in infancy and childhood. Current treatment methods for high risk neuroblastomas, consisting of surgery, radiation, and multi-modal chemotherapy, have not been effective in significantly improve survival rate. There is an urgent need for efficacious treatments. We are creating a new therapeutic agent for treating neuroblastomas. Our novel approach is to use protein-lipid nanovesicles that can preferentially seek cancer and selectively destroy tumor cells without damaging normal cells. We are investigating the cancer-selective targeting and killing mechanism of the nanovesicles using human neuroblastoma cells and animal models. Success in the proposed research studies will enable us to test the product in humans.