Hematopoietic stem cell based gene therapy of breast cancer

 描述（由申请人提供）：尽管乳腺癌对手术和mAb/化疗的初始应答率很高，但大多数患者会复发，并伴有治疗耐药疾病，维持完全缓解已被证明是难以实现的。目前所有针对卵巢癌患者的经典和实验性治疗方案都集中在破坏恶性细胞上。这些遗传不稳定和异质的细胞是治疗的移动目标。肿瘤间质含有遗传上稳定的肿瘤浸润性髓样细胞，其中肿瘤相关巨噬细胞（TAM）是优势种。该方案的核心新思想是利用造血干细胞（HSC）募集到肿瘤基质的病理生理过程将治疗基因递送到肿瘤中。我们提出了一个简单的程序，包括G-CSF/AMD 3100动员和静脉注射HD-Ad 5/35++载体，以遗传工程改造癌症患者的HSC。这些HSC将提供遗传修饰的TAM祖细胞的长期来源，这些祖细胞将被肿瘤积极招募。一旦分化成TAM，基因表达系统将被激活，从而允许消除TAM和邻近的肿瘤细胞。潜在地，我们的方法还可以允许基于TAM的募集和TAM特异性报告基因表达的激活的复发性乳腺癌的早期检测。该提案的目标是增加转基因表达TAM的百分比，并测试体内基因工程HSC是否可用于乳腺癌检测和治疗。具体目标是：具体目标1。允许基因工程HSC体内扩增的测试方法。具体目标2：跟踪TAM分化和募集到肿瘤，并测试这是否可用于乳腺癌的早期检测。具体目标3。在小鼠乳腺癌模型中测试选择性杀死TAM和邻近肿瘤细胞是否会阻止肿瘤生长。

 DESCRIPTION (provided by applicant): Although initial response rates of breast cancer to surgery and mAb/chemotherapy are high, most patients will recur with treatment resistant disease, and maintaining complete remission has proven elusive. All of the current classical and experimental treatment options for ovarian cancer patients are focused on destroying the malignant cells. These genetically unstable and heterogeneous cells are a moving target for therapies. The tumor stroma contains genetically stable tumor-infiltrating myeloid cells, of which the tumor-associated macrophages (TAMs) are the dominant species. The central new idea of this proposal is to use the patho-physiological process of recruitment of hematopoietic stem cells (HSC) to the tumor stroma to deliver therapeutic genes into tumors. We propose a simple procedure involving G-CSF/AMD3100 mobilization and intravenous HD-Ad5/35++ vector injection to genetically engineer HSCs in cancer patients. These HSCs will provide a long-term source of genetically modified TAM progenitors that will be actively recruited by the tumor. Once differentiated into TAMs, a gene expression system will be activated that allows for the elimination of TAMs and neighboring tumor cells. Potentially our approach can also allow for the early detection of recurrent breast cancer based on the recruitment of TAMs and activation of TAM-specific reporter gene expression. The goals of this proposal are to increase the percentage of transgene-expressing TAMs and to test whether in vivo gene-engineered HSCs can be used for breast cancer detection and therapy. The Specific Aims are: Specific Aim 1. Test approaches that allow for the in vivo expansion of gene-engineered HSCs. Specific Aim 2: Track TAM differentiation and recruitment to tumor and test whether this can be used for early detection of breast cancer. Specific Aim 3. Test whether the selective killing of TAMs and neighboring tumor cells stops tumor growth in mouse breast cancer models.