Antiangiogenic Gene Therapy of Ovarian and Breast Cancers

血管生成对于肿瘤的生长和转移是重要的。因此，抑制血管生成可以 补充卵巢癌和乳腺癌的辅助化疗。两大类内源性 目前正在研究血管生成抑制剂;胶原蛋白的蛋白水解裂解产物， 凝血相关蛋白内皮抑素是一个20 kDa的非胶原结构域的C-末端片段， (NC1)XVIII型胶原蛋白。内皮抑素治疗可导致不同程度的肿瘤生长抑制 在许多临床前肿瘤模型中。答复不一致的原因之一是， 蛋白质折叠受用于制备抗血管生成药物的表达系统类型的影响 分子。我们已经鉴定并表征了一种突变型内皮抑素，其含有脯氨酸取代为 在位置125处的丙氨酸残基。P125 A-内皮抑制素显示与内皮细胞的结合增加， 比天然分子更好地抑制血管生成。在NCI和我们的实验室进行的独立研究 证实了突变内皮抑素在抑制肿瘤生长方面比三种天然蛋白质更好。 不同的肿瘤模型系统。因此，重要的是要了解功能的重要性， 在这个位置上进行替换。胶原XVIII的NC 1结构域的多态性主要涉及截短 并导致与Knobloch综合征相关的血管问题。另一种已知的变异是 D104 N，但不影响内皮抑制素的生物活性。目前还没有多态性 在P125中识别。在具体目标1中，我们提出系统地产生其他P125取代， 研究突变体的相对抗血管生成效力。将进行机制研究， 鉴定内皮抑制素生物活性的突变特异性变化。在具体目标2中，我们建议 评价在哺乳动物中表达的突变内皮抑制素的治疗和药物毒理学性质 细胞最初的研究将集中在比较使用Alzet泵和AAV的蛋白质治疗的疗效上。 介导的基因治疗基于这些结果，我们将严格评估一个选定的突变内皮抑制素， 临床相关的卵巢癌和乳腺癌模型。最近的研究表明， 肿瘤生长时，化疗与突变内皮抑制素治疗相结合。的机理 将研究这两种方法之间的协同作用，以促进加速临床开发， 这种方法有助于加速这种方法的临床开发。

Angiogenesis is important for the growth and metastasis of cancer. Inhibition of angiogenesis can therefore complement adjuvant chemotherapy of ovarian and breast cancer. Two major groups of endogenous angiogenesis inhibitors are currently investigated; proteolytic cleavage products of collagens and coagulation related proteins. Endostatin is a 20 kDa-C-terminal fragment of the non-collagenous domain (NC1) of collagen type XVIII. Endostatin treatment had resulted in varying degree of tumor growth inhibition in a number of preclinical tumor models. One of the reasons for the inconsistencies in response is due to protein folding which is affected by the type of expression system used to prepare the antiangiogenic molecule. We have identified and characterized a mutant endostatin containing a substitution of proline to alanine residue at position 125. P125A-endostatin showed increased binding to endothelial cells and inhibited angiogenesis better than the native molecule. Independent studies at NCI and in our laboratory confirmed that the mutant endostatin is better in inhibiting tumor growth than the native protein in three different tumor model systems. Therefore, it is important to understand the functional importance of substitutions at this position. Polymorphism in the NC1 domain of collagen XVIII mostly involves truncations and leads to vascular problems associated with Knobloch syndrome. The only other known mutation is D104N which however does not affect the biological activity of endostatin. No polymorphism has been yet identified at P125. In specific aim 1 we propose to systematically generate other P125 substitutions and investigate the relative antiangiogenic potency of the mutants. Mechanistic studies will be carried out to identify mutation specific changes in the biological activity of endostatin. In specific aim 2 we propose to evaluate the therapeutic and pharmacotoxicologic properties of mutant endostatins expressed in mammalian cells. Initial studies will focus on comparing the efficacy of protein therapy using Alzet pumps and AAV- mediated gene therapy. Based on these results we will critically evaluate a selected mutant endostatin in clinically relevant ovarian and breast cancer models. Recent studies have shown improved inhibition of tumor growth when chemotherapy was combined with mutant endostatin treatment. The mechanism of synergy between these two methods will be investigated so as to facilitate expedited clinical development of this approach, facilitate expedited clinical development of this approach.