The ODC A allele as a driver and therapeutic target of aggressive prostate cancer in African American men

项目摘要 非裔美国人男性前列腺癌的发病率和死亡率要高得多。 与欧洲裔美国人(EAM)相比，这些种族之间的基因变异起着至关重要的作用。我们的 研究表明，指导多胺生物合成的基因在 AAM与EAM PCA的对比，表明这一途径可能在推动癌症健康方面发挥重要作用 贫富差距。 鸟氨酸脱羧酶(ODC)是多胺生物合成的第一个限速酶。值得注意的是， ODC基因具有+316碱基的单核苷酸多态(SNP)，其中腺嘌呤(A)被取代 鸟嘌呤(G)，这个SNP增强ODC启动子的活性。重要的是，ODCA等位基因在 AAM而不是EAM，表明AAM中具有ODC A等位基因的前列腺癌患者的ODC水平将会增加 这推动了侵略性的前列腺癌生物学。此外，二氟甲基鸟氨酸(DFMO)，a 选择性ODC抑制剂，是一种高效的化学预防药物，适用于携带至少一种 ODC A等位基因，提示ODC A等位基因将预测受益于DFMO治疗的AAM PCa患者。 这些数据支持我们的假设，即ODC A等位基因既是侵袭性前列腺癌的驱动因素 生物学和非裔美国人男性的目标脆弱性。为了验证这一假设，在目标1中，我们将 使用等位基因识别分析检测来自PCa病例的~3,800个DNA样本(~1,520个AAM：~2,280个EAM) 以及ODC A等位基因存在的对照：(I)确定其在两个种族中的频率；以及(Ii)评估 ODC A等位基因意味着患者预后更差。在目标2中，我们将产生三组等基因的PCA细胞 我们将测试带有ODC A等位基因的PCA细胞是否增加了 与等基因PCA相比，ODC和多胺水平以及具有更多侵袭性的生物学表型 携带ODC G等位基因的细胞。在目标3中，我们将测试是否用DFMO和多胺处理我们的同基因细胞 转运抑制剂(多胺阻断疗法)对PCa细胞的表型有不同的影响 ODC A和ODC G等位基因。最后，我们还将测试多胺阻断是否有不同的作用 含ODC A等位基因的AAM与仅含ODC G的AAM原发PCa组织外植体的治疗 等位基因。 我们提出，拟议的研究将通过建立ODC A而使非裔美国人PCA患者受益 等位基因作为预测预后的生物标志物，将有助于医生评估患者的风险，并作为预测 预测DFMO作为化疗治疗成功的生物标志物。

Project Summary The rates of prostate cancer (PCa) incidence and mortality are much higher in African American men (AAM) versus European American men (EAM), and genetic variations between these races play a critical role. Our studies have shown that expression of genes that direct polyamine biosynthesis are significantly elevated in AAM versus EAM PCa, suggesting this pathway may play important roles in driving this cancer health disparity. Ornithine decarboxylase (ODC) is the first and rate-limiting enzyme of polyamine biosynthesis. Notably, the ODC gene has a single nucleotide polymorphism (SNP) at base +316 in which adenine (A) is substituted for guanine (G), and this SNP augments ODC promoter activity. Importantly, the ODC A allele is more common in AAM than EAM, suggesting prostate tumors in AAM having an ODC A allele will have increased ODC levels and that this drives aggressive prostate tumor biology. Furthermore, difluoromethylornithine (DFMO), a selective ODC inhibitor, is a highly effective chemoprevention agent in high-risk men harboring at least one ODC A allele, suggesting the ODC A allele will predict AAM PCa patients that benefit from DFMO treatment. These data support our hypothesis that the ODC A allele is both a driver of aggressive prostate tumor biology and a targetable vulnerability in African American men. To test this hypothesis, in Aim 1 we will use an allelic discrimination assay to test ~3,800 DNA samples (~1,520 AAM: ~2,280 EAM) from PCa cases and controls for the presence of the ODC A allele to: (i) establish its frequency in both races; and (ii) assess if the ODC A allele connotes worse patient outcomes. In Aim 2, we will generate three sets of isogenic PCa cell lines by CRISPR-based prime editing, where we will test if PCa cells with an ODC A allele have increased levels of ODC and polyamines and have more aggressive biological phenotypes compared to isogenic PCa cells with ODC G alleles. In Aim 3, we will test if treatment of our isogenic cells with DFMO and a polyamine transport inhibitor (polyamine blockage therapy) has differential effects on the phenotypes of PCa cells having ODC A versus ODC G alleles. Finally, we will also test if there are differential effects of polyamine blocking therapy on primary PCa tissue explants from AAM having an ODC A allele versus AAM with only ODC G alleles. We submit the proposed studies will benefit African American PCa patients by establishing the ODC A allele as a prognostic biomarker that will be useful for doctors to assess patient risk, and as a predictive biomarker that forecasts the success of DFMO as a chemotherapeutic treatment.