Antiangiogenic Gene Therapy of Ovarian and Breast Cancers

血管生成对肿瘤的生长和转移具有重要作用。因此，抑制血管生成可以 补充辅助化疗治疗卵巢癌和乳腺癌。内源性的两大群体 目前正在研究血管生成抑制药；胶原蛋白的蛋白水解物和 凝血相关蛋白。内皮抑素是非胶原域的20 kDa-C末端片段 (Nc1)XIII型胶原蛋白。内皮抑素治疗导致不同程度的肿瘤生长抑制 在一些临床前肿瘤模型中。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。我们已经鉴定并鉴定了一种突变的内皮抑素，它含有一个由脯氨酸取代的 丙氨酸残留量在125位。P125A-内皮抑素与内皮细胞的结合增加 抑制血管生成的作用强于天然分子。在NCI和我们的实验室进行的独立研究 证实突变的内皮抑素在抑制肿瘤生长方面比天然蛋白更好 不同的肿瘤模型系统。因此，了解的功能重要性非常重要 在这个位置上的替换。XVIII胶原蛋白NC1域的多态主要涉及截断 并导致与诺布洛克综合征相关的血管问题。唯一已知的另一个突变是 D104N，但不影响内皮抑素的生物学活性。到目前为止还没有多态性 在第125页确认。在具体目标1中，我们建议系统地产生其他P125替换和 研究突变体的相对抗血管生成能力。将进行机理研究，以 确定内皮抑素生物活性的突变特异性变化。在具体目标2中，我们建议 哺乳动物表达的突变型内皮抑素的治疗和药毒学特性评价 细胞。初步研究将侧重于比较使用阿尔茨海默特泵和AAV的蛋白质疗法的疗效。 介导性基因治疗。基于这些结果，我们将对选定的内皮抑素突变体进行批判性评估 临床相关的卵巢癌和乳腺癌模型。最近的研究表明，抑制作用有所改善 当化疗联合突变内皮抑素治疗时，肿瘤生长。它的作用机制 将研究这两种方法之间的协同作用，以促进加快临床研究 这种方法，促进了这种方法的加速临床开发。

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.