TMEM108 IS A NOVEL TARGET IN NEUROBLASTOMA

神经母细胞瘤（NB）是儿童颅外最常见的恶性实体瘤， 超过15%的儿童癌症相关死亡。尽管疾病结果总体上有所改善， MYCN扩增（MYCNA）NB在很大程度上仍然是一种不治之症。与成人肿瘤不同， NB中的突变相对较少发生。因此，致癌信号转导的失调可能 有助于NB肿瘤发生。 这项提案将通过定义跨膜蛋白108的作用和调节来实现这一目标 在NB恶性肿瘤中的TMEM108抑制作用，并检查TMEM108抑制对NB细胞增殖和 原位小鼠模型中的肿瘤生长。TMEM108是一种潜在的细胞表面受体样蛋白，具有 在N-末端的用于蛋白分泌的信号肽序列和细胞外结构域和细胞内结构域 由跨膜序列分隔的结构域。TMEM108在NB肿瘤样品中高度过表达 在Versteeg-88数据集中，其过表达显著预测不良的患者结果（R2： http://r2.amc.nl TMEM108是一种完全未表征的基因，其在NB肿瘤和细胞系中富集。 在我们的初步研究中，我们发现TMEM108表达的敲低或敲除引起了细胞凋亡。 在一个MYCN扩增的NB细胞系和一个MYCN非扩增的NB细胞系中存在细胞增殖缺陷。另外我们也 发现过表达TMEM108突变体（mt）并缺失其胞内结构域可抑制NB 与载体对照和TMEM 108全长野生型（wt）相比的细胞增殖。兔多克隆 靶向其细胞外结构域的抗体抑制了NB细胞在培养物中的增殖和肿瘤生长。 原位异种移植小鼠模型。这些发现有力地表明TMEM 108介导了肿瘤的发生。 NB细胞中的信号通路。因此，通过抑制性抗体靶向TMEM 108胞外结构域或 其下游信号通路具有很大的潜力，可作为NB的新治疗选择 患者 这项工作的中心假设是，TMEM 108是NB中抗体的理想分子靶标， 基于治疗。所提出的实验将通过确定TMEM 108的作用来测试该假设。 抑制细胞培养物和原位小鼠模型中NB肿瘤生长。本项目的具体目标 是：1）确定TMEM 108在NB恶性肿瘤的调节中的功能;和2）确定TMEM 108在NB恶性肿瘤中的作用。 TMEM108体内抑制的治疗潜力。 靶向TMEM108是未来NB治疗的新概念。该项目如果成功， 将确立TMEM108作为NB的治疗靶点。TMEM108抑制不仅可以作为独立的抑制剂， 治疗，而且还可以作为当前化疗方案的有效辅助治疗这种侵袭性疾病 小儿恶性肿瘤

Neuroblastoma (NB) is the most common extracranial malignant solid tumor in children and contributes to more than 15% of all pediatric cancer-related deaths. Despite the overall improvement in the disease outcome, MYCN-amplified (MYCNA) NB largely remains an incurable disease. Unlike in adult tumors, recurrent somatic mutations in NB occur with relative paucity. Therefore, de-regulation of oncogenic signal transduction may contribute to NB tumorigenesis. This proposal will pursue that goal by defining the role and regulation of transmembrane protein 108 (TMEM108) in NB malignancy and examining the effect of TMEM108 inhibition on NB cell proliferation and tumor growth in an orthotopic mouse model. TMEM108 is a potential cell surface receptor-like protein with a signal peptide sequence at the N-terminal for protein secretion and an extracellular domain and intracellular domain separated by a transmembrane sequence. TMEM108 is highly overexpressed in NB tumor samples and its overexpression significantly predicts poor patient outcome in the Versteeg-88 data set (R2: http://r2.amc.nl). TMEM108 is a completely uncharacterized gene that is enriched in NB tumors and cell lines. In our preliminary studies, we have found that knockdown or knockout of TMEM108 expression caused a cell proliferation defect in one MYCN-amplified and one MYCN-non-amplified NB cell lines. In addition, we also found that overexpression of TMEM108 mutant (mt) with the deletion of its intracellular domain inhibited NB cell proliferation compared to vector control and TMEM108 full-length wild-type (wt). Rabbit polyclonal antibodies targeting its extracellular domain inhibited NB cell proliferation in culture and tumor growth in an orthotopic xenograft mouse model. These findings strongly suggest that TMEM108 mediates an oncogenic signaling pathway in NB cells. Therefore, targeting TMEM108 extracellular domain by an inhibitory antibody or its downstream signaling pathway has a great potential to be eastablished as novel treatment options for NB patients. The central hypothesis of this work is that TMEM108 is an ideal molecular target in NB for an antibody- based therapy. The proposed experiments will test this hypothesis by determining the effect of TMEM108 inhibition on NB tumor growth in cell culture and in an orthotopic mouse model. The specific aims for this project are: 1) to determine the function of TMEM108 in the regulation of NB malignancy; and 2) to determine the therapeutic potential of TMEM108 inhibition in vivo. Targeting TMEM108 is a novel concept in the future treatment of NB. The proposed project, if successful, will establish TMEM108 as a therapeutic target in NB. TMEM108 inhibition may serve not only as a stand-alone therapy but also as an effective adjunct to current chemotherapeutic regimens for treating this aggressive pediatric malignancy.