Functional Analysis of HOXA13 Small Molecule Antagonists

描述（由申请人提供）：本项目将专注于HOXA 13小分子抑制剂的开发和体内表征，作为减少肿瘤血管形成的疗法。在胚胎发生过程中，HOX蛋白通过调节基因簇来指导组织和器官的发育，这些基因簇的产物控制组织的特化和分化。我们已经确定HOXA 13调节一组在发育中的胚胎中血管发育所必需的促血管基因。更重要的是，我们已经确定了许多相同的血管原基因在肝癌的血管发展中受到HOXA 13的调控。由于HOXA 13以多效性方式调节血管发育，因此我假设HOXA 13转录功能的破坏将通过同时影响肿瘤血管发生所需的一组基因的表达来有效地抑制肿瘤血管形成。认识到HOXA 13的转录功能需要DNA结合，我们开发了一种小分子筛选来鉴定能够阻止HOXA 13与其靶DNA序列相互作用的化合物。从这个筛选中，我们鉴定了化合物B（CpdB），一种可以部分抑制HOXA 13调节一组前血管基因的能力的小分子。通过仔细修改CpdB的初始结构，我假设可以提高这种小分子的功效，以抑制HOXA 13在肿瘤发展中的功能。为了检验这一假设，将实现以下具体目标：目标1。确定CpdB对HOXA 13的特异性。目标2.定量CpdB对HOXA 13的亲和力，并确定HOXA 13 DNA结合结构域内哪些氨基酸残基与CpdB接触。目标3。测定HOXA 13和CpdB的结构活性关系，优化CpdB效力，并改善CpdB溶解度。目标4。确定CpdB类似物在肿瘤发展中干扰HOXA 13调节的前血管基因表达的功效。公共卫生相关性：拟议的研究将开发一系列新鉴定的HOXA 13小分子拮抗剂，以抑制血管生成。这些发现的应用将转化为新的治疗方法，以防止肿瘤血管化和生长。

DESCRIPTION (provided by applicant): This project will focus on the development and in vivo characterization of small molecule inhibitors of HOXA13 as a therapy for reducing tumor vascularization. During embryogenesis, HOX proteins direct tissue and organ development by regulating clusters of genes whose products control tissue specification and differentiation. We have established that HOXA13 regulates a cluster of pro-vascular genes necessary for vascular development in the developing embryo. More importantly, we have determined that many of the same provascular genes are regulated by HOXA13 in the developing vasculature of hepatocarcinomas. Because HOXA13 functions in a pleiotropic manner to regulate vascular development, I hypothesize that the disruption of HOXA13's transcriptional function would effectively inhibit tumor vascularization by simultaneously affecting the expression of a cohort genes required for tumor vasculogenesis. Recognizing that DNA binding is required for HOXA13's transcriptional function, we developed a small molecule screen to identify compounds capable of preventing HOXA13 from interacting with its target DNA sequence. From this screen, we identified Compound B (CpdB), a small molecule that can partially inhibit HOXA13's ability to regulate a group of provascular genes. Through careful modifications to CpdB's initial structure, I hypothesize that the efficacy of this small molecule can be improved to inhibit HOXA13 function in developing tumors. To test this hypothesis, the following specific aims will be accomplished: Aim 1. Determine the specificity of CpdB for HOXA13. Aim 2. Quantitate the affinity of CpdB for HOXA13 and determine which amino acid residues within the HOXA13 DNA binding domain are contacted by CpdB. Aim 3. Determination of structure activity relationships for HOXA13 and CpdB, optimization of CpdB potency, and improvement of CpdB solubility. Aim 4. Determine the efficacy of CpdB analogs to perturb HOXA13-regulated provascular gene expression in developing tumors. PUBLIC HEALTH RELEVANCE: The proposed investigations will develop a newly identified series of HOXA13 small molecule antagonists for their potential to inhibit vasculogenesis. Applications of these findings will translate into new therapies to prevent tumor vascularization and growth.