Development of Small Molecule Radiation Sensitizers

描述(由申请人提供)： 我们合成了一个新的合成化学文库，并将其用于正向化学遗传学筛选，旨在识别内皮细胞形态发生的小分子抑制物。这一筛选结果导致了结构相关的小分子的鉴定，这些小分子抑制内皮细胞的增殖、迁移、在基质中形成小管样结构的能力，以及使用背部皮肤皱褶血管窗腔显示的新血管生成。生化分析表明，这些新的小分子对ENOX1有抑制作用，ENOX1是一种质膜相关酶，具有蛋白二硫键-硫醇交换活性。虽然Enox活性对细胞增殖很重要，但其分子机制还不是很清楚。ShRNA介导的抑制HUVECs中Enox活性的作用抑制了内皮细胞的迁移和基质细胞内小管样结构的形成，重现了小分子抑制剂的作用。ENOX1的小分子抑制作用与电离辐射诱导内皮细胞凋亡显著增加有关。集落形成实验表明，这些小分子增加了内皮细胞的辐射敏感性。相反，肿瘤上皮细胞的辐射敏感性不受小分子的影响。分割X射线照射前给予小分子ENOX1抑制剂后，表达Lewis肺癌(LLC)肿瘤相关微血管的CD34的数量和密度在统计学上显著减少。LLC和人HT29结肠癌肿瘤模型的使用表明，与单独照射相比，小分子ENOX1抑制剂联合分割X射线照射产生的肿瘤生长延迟在统计学上显著增加。当小鼠接受120 mg/kg的团注时，在30天的间隔内没有观察到急性毒性的证据。这些初步数据支持这样的假设，即ENOX1是提高电离辐射控制肿瘤生长能力的基本分子靶点。这一应用程序的短期目标是验证这一假设。长期目标是将这些小分子抑制剂开发成具有临床疗效的辐射增敏剂。 公共卫生相关性： 正向化学遗传学筛查确定内皮细胞形态发生的小分子抑制物。生化分析表明，这些新的小分子抑制ENOX1酶，增加内皮细胞的辐射敏感性，增加辐射对肿瘤相关血管的抑制，从而抑制肿瘤的生长。这些初步数据支持这样的假设，即ENOX1是提高电离辐射控制肿瘤生长能力的基本分子靶点。

DESCRIPTION (provided by applicant): We synthesized a novel synthetic chemical library and used it in a forward chemical genetics screen designed to identify small molecule inhibitors of endothelial morphogenesis. This screen resulted in the identification of structurally-related small molecules that inhibited endothelial cell proliferation, migration, the ability to form tubule-like structures in matrigel, as well as neo- angiogenesis visualized using a dorsal skin fold vascular window chamber. Biochemical analysis revealed that the novel small molecules inhibited ENOX1, a plasma membrane- associated enzyme that exhibits protein disulfide-thiol interchange activity. While ENOX activity is important for cellular proliferation, the molecular mechanisms are not well understood. shRNA-mediated inhibition of ENOX activity in HUVECs inhibited endothelial cell migration and formation of tubule-like structures in matrigel, reproducing the effects of the small molecule inhibitors. Small molecule inhibition of ENOX1 was associated with a significant increase in endothelial cell apoptosis induced by ionizing radiation. Colony formation assays demonstrated that these small molecules increased the radiation sensitivity of endothelial cells. In contrast, the radiation sensitivity of tumor epithelial cells was unaffected by the small molecules. Administration of a small molecule ENOX1 inhibitor prior to fractionated X-irradiation produced a statistically significant decrease in the number and density of CD34 expressing Lewis Lung Carcinoma (LLC) tumor-associated microvasculature. Use of LLC and human HT29 colon carcinoma tumor models demonstrated that the small molecule ENOX1 inhibitors coupled with fractionated X-irradiation produced a statistically significant increase in tumor growth delay compared to irradiation alone. No evidence of acute toxicity was observed over a 30 day interval when mice received a bolus injection of 120 mg/kg. These preliminary data support the hypothesis that ENOX1 represents a rationale molecular target for increasing the ability of ionizing radiation to control tumor growth. The short term goal of this application is to valid this hypothesis. The long term goal is to develop these small molecule inhibitors into a radiation sensitizer that exhibits clinical efficacy. PUBLIC HEALTH RELEVANCE: A forward chemical genetics screen identifies small molecule inhibitors of endothelial morphogenesis. Biochemical analysis revealed that these novel small molecules inhibited the enzyme ENOX1, increased the radiation sensitivity of endothelial cells, increased radiation- mediated suppression of tumor-associated vasculature, thereby suppressing tumor growth. These preliminary data support the hypothesis that ENOX1 represents a rationale molecular target for increasing the ability of ionizing radiation to control tumor growth.