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，寻找和破坏人类神经母细胞瘤。神经母细胞瘤是婴儿和儿童最常见的癌症。高危神经母细胞瘤即使采用最积极的联合或多模式治疗也难以治愈。我们的初步研究表明，使用新的蛋白脂质纳米囊泡靶向和治疗神经母细胞瘤的可行性，副作用最小。纳米囊泡由小的融合溶酶体蛋白saposin C（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纳米囊泡对暴露在癌细胞和新血管表面上的磷脂酰丝氨酸（PS）具有优先亲和力。我们已经表明，纳米囊泡在神经母细胞瘤肿瘤中具有高的积聚倾向，并诱导癌细胞的凋亡。在携带神经母细胞瘤的动物中重复注射SapC-DOPS后，我们观察到通过酸性鞘磷脂酶衍生的神经酰胺介导的信号传导途径诱导凋亡性癌细胞死亡对肿瘤生长的显著抑制作用。本提案的目的是确定SapC-DOPS纳米囊泡在治疗神经母细胞瘤中的应用。具体目的是（1）确定人神经母细胞瘤细胞的细胞表面PS水平与对SapC-DOPS纳米囊泡的靶向和细胞毒性应答的关系，（2）开发特异性促进人神经母细胞瘤表面PS暴露的SapC-DOPS敏化剂，（3）探讨SapC-DOPS通过神经酰胺介导的神经元中心信号通路诱导人神经母细胞瘤细胞凋亡的分子机制。这项研究是创新的，因为SapC-DOPS纳米囊泡提供了一种独特的方法来寻找和治疗神经母细胞瘤，以及其他具有细胞表面暴露PS的肿瘤。该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，最常见于婴儿和儿童。目前治疗高危神经母细胞瘤的方法包括手术、放疗和多模式化疗，但均不能显著提高生存率。迫切需要有效的治疗方法。我们正在开发一种新的治疗神经母细胞瘤的药物。我们的新方法是使用蛋白质-脂质纳米囊泡，它可以优先寻找癌症并选择性地破坏肿瘤细胞而不损害正常细胞。我们正在使用人类神经母细胞瘤细胞和动物模型研究纳米囊泡的癌症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中测试该产品。

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.