EPISOMAL VECTORS FOR BREAST CANCER GENE THERAPY

基因疗法目前被用于治疗多种癌症，包括脑癌、前列腺癌和卵巢癌。然而，如果要充分利用基因转移技术，还需要克服许多障碍。非病毒载体发展的一个重要障碍是瞬时转染的肿瘤细胞中基因表达的迅速下降。为了克服这一缺陷，哥白尼开发了一种新的SV40大T抗原突变体，以驱动含有SV40 DNA起源的质粒的染色体外复制。这种经过安全修饰的T抗原不能结合宿主肿瘤抑制基因产物，但仍具有复制能力，允许载体复制到每个人类细胞数千个拷贝，并产生高水平的基因表达。通过融合人类孕酮受体的一部分激素结合域，我们能够使用fda批准的孕酮拮抗剂RU486进行外部控制载体扩增。我们现在建议利用我们的安全修饰的、外部调节的episomal表达载体开发一种乳腺癌特异性episomal表达系统。建议的商业应用：非病毒基因治疗表达载体受到适度基因表达水平的限制。我们已经开发了一种外体细胞质粒载体，在外界控制下在人类细胞染色体外复制，并产生高水平的基因表达。这种episomal载体有潜力成为一种有效的癌症治疗方法，并可纳入治疗各种癌症适应症。

Gene therapy is currently being used to treat a variety of cancers, including brain, prostate and ovarian carcinoma. However, there are many obstacles that need to be overcome if gene transfer technologies are to be fully exploited. A significant obstacle in the development of non- viral vectors is the rapid decline of gene expression in transiently transfected tumor cells. To overcome this deficiency, Copernicus has developed a novel SV40 large T antigen mutant to drive extrachromosomal replication of plasmids containing an SV40 DNA origin. This safety-modified T antigen is unable to bind host tumor suppressor gene products but remains replication-competent, allowing the vector to replicate to several thousand copies per human cell, and yielding high levels of gene expression. By fusing a portion of the hormone binding domain of the human progesterone receptor, we able to externally-control vector amplification using the FDA-approved progesterone antagonist RU486. We now propose to develop a breast cancer specific episomal expression system utilizing our safety-modified, externally-regulated episomal expression vector. PROPOSED COMMERCIAL APPLICATIONS: Non-viral gene therapy expression vectors are limited by modest levels of gene expression. We have developed an episomal plasmid vector that replicates extrachromosomally in human cells under external control, and generates high levels of gene expression. This episomal vector has the potential to be an effective cancer therapeutic, and could be incorporated into treatments for diverse cancer indications.