EWS/FLI-1: TARGET FOR RADIOSENSITIZATION & GROWTH INHIBITION OF EWING TUMORS

描述（由申请人提供）：尤因肉瘤（ES）是一种实体高度恶性肿瘤 骨头和软组织的组织它最常影响儿童和青少年，是年轻人中第二常见的恶性骨肿瘤。ES由神经外胚层来源的低分化圆形细胞形成。目前的ES治疗包括放疗和化疗的联合方式。临床上，ES肿瘤通常对这种治疗有反应，但总体治愈率低，因为ES是一种侵袭性溶骨性肿瘤，经常出现转移性疾病。ES细胞的特征是在几乎100%的情况下具有11号和22号染色体之间的相互易位，或者更少地具有21号和22号染色体之间的相互易位。这种易位导致在这些细胞中合成融合蛋白，其N-末端由EWS基因序列编码，其C-末端由FLI-1基因（最常见）或ERG基因的序列编码，两者都是转录因子ETS家族的成员。融合类型有限，其中涉及EWS/FLI-1的融合类型最常在ES患者中检测到。我们已经发现，ES细胞中EWS/FLI-1的下调导致生长抑制和对以下物质的敏感性： 通过电离辐射和化学治疗剂的细胞凋亡。我们的总体目标是定义 靶向EWS/FLI-1（或EWS/ERG）交界处的反义寡核苷酸， 这是用于ES管理的治疗工具，因为在正常细胞中没有靶融合序列。 我们的中心假设是，反义EWS/FLI-1寡核苷酸靶向的易位连接将专门使ES细胞敏感的DNA损伤剂，此外，将防止致癌活性的EWS/FLI-1蛋白质产品。用反义EWS/FLI-1寡核苷酸治疗将具有双重作用，增强ES细胞杀伤和下调细胞肿瘤性质。提出了两个具体的目标，其中包括实验设计，以研究反义EWS/FLI-1寡核苷酸在体外的影响，对培养ES细胞系，和在体内，对小鼠的ES细胞注射诱导的肿瘤。这些研究将促进技术和科学的理解，在未来的翻译应用反义EWS/FLI-1寡核苷酸ES治疗。

DESCRIPTION (provided by applicant): Ewing's sarcoma (ES) is a solid highly malignant neoplasm of the bone and soft tissues. Most often it affects children and young adolescents, being the second most common malignant bone tumor in young adults. ES is formed by poorly differentiated round cells of neuroectodermal origin. Current ES treatment includes a combined modality with radiotherapy and chemotherapy. Clinically, ES tumors are generally responsive to such treatment, but the overall cure rate is low because ES is an aggressive osteolytic tumor that frequently presents with metastatic disease. ES cells are characterized for having, in nearly 100 percent of the cases a reciprocal translocation between chromosomes 11 and 22 or, much less frequently, 21 and 22. This translocation results in the synthesis in these cells of fusion proteins with their N-terminus encoded by EWS gene sequences and their C- terminus encoded by sequences of either the FLI-1 gene, most frequently, or the ERG gene, both members of the ETS family of transcription factors. There is a limited repertoire of fusion types, with those involving EWS/FLI-1 being most frequently detected in ES patients. We have found that down-regulation of EWS/FLI-1 in ES cells caused both growth inhibition and sensitization to apoptosis by ionizing radiation and chemotherapeutic agents. Our overall objective is to define antisense oligonucleotides targeted to the EWS/FLI-1 (or EWS/ERG) junction as highly specific therapeutic tools for ES management, because there are no target fusion sequences in normal cells. Our central hypothesis is that antisense EWS/FLI-1 oligonucleotides targeted to the translocation junction will specifically render ES cells sensitive to DNA-damaging agents and, in addition, will prevent the oncogenic activity of the EWS/FLI-1 protein product. Treatment with antisense EWS/FLI-1 oligonucleotides will have a dual effect, enhancing ES cell killing and down-regulating cellular neoplastic properties. Two specific aims are proposed, which include experiments designed to study the effects of antisense EWS/FLI-1 oligonucleotides in vitro, on cultures ES cell lines, and in vivo, on tumors induced in mice by injection of ES cells. These studies should advance technological and scientific understanding for the translational application of antisense EWS/FLI-1 oligonucleotides to ES treatment in the future.