HSET as a racial disparity biomarker for TNBC patients

摘要！ 非洲血统是三阴性乳腺癌（TNBC）预后不良的风险因素。然而，尽管如此， 非洲裔美国人（AA）的预后工具和治疗方案与欧洲裔美国人没有差异 (EA)TNBC患者AA TNBC患者的个性化药物受到以下事实的阻碍， 人口高度混合，因此自我报告的种族往往不能准确反映非洲遗传祖先。 也缺乏使用祖先分析肿瘤生物标志物和临床结果的研究- 对TNBC标本进行基因分型。此外，很少有临床前TNBC研究在实验设计中考虑种族， 和AA TNBC患者在临床试验中的代表性明显不足。一个关键的障碍， 改善AA TNBC患者的结局是缺乏预后工具和治疗方式， 精确地针对这个病人群体。该项目的广泛、长期目标是使发展 通过提高核HSET（nHSET）作为 AA TNBC的预后生物标志物以及TNBC种族差异的分子机制 攻击性以及如何瞄准。我们的实验室已经发现，HSET更强烈地促进 AA细胞的增殖和迁移能力明显高于EA TNBC细胞。此外，nHSET独立预测不良 结果在AA，但不是EA TNBC，但这必须在占非洲遗传百分比后得到验证。 多变量生存模型和非洲本土TNBC的祖先。我们提出的项目有三个目标。 首先，将针对TNBC患者样本的大队列确定非洲遗传祖先的比例 从美国和尼日利亚获得，我们将确定nHSET是否可以作为种族差异的生物标志物， 在调整其非洲遗传血统百分比后，对TNBC进行分层。第二，由于HSET和MYH 9 是核结合伴侣，可能有助于染色质修饰以扩增致癌Wnt/β-连环蛋白 信号传导和MYC表达（我们发现与EA TNBC相比，其富含AA），我们将 使用患者来源的样品表征TNBC中HSET-MYH 9-MYC轴的种族差异， 将这些种族差异与TNBC中基因组稳定性的差异相关联。我们将使用多种颜色的lenti- CRISPR-Cas9系统，用于敲除AA/EA细胞系中该轴中的关键基因，以测试HSET-MYH 9-MYC 轴驱动肿瘤侵袭性在AA中比在EA TNBC中更强。在目标3中，一个有前途的 将在AA和EA TNBC患者来源的异种移植物模型中测试市售的HSET抑制剂。 细胞因此，本研究将检验nHSET是一种新的治疗上可行的生物标志物的假设， AA比EA TNBC患者更有价值，更强烈地推动TNBC进展和化疗耐药性 在AA患者中比EA TNBC患者中。该项目的影响将是推进预后生物标志物的知识， 疾病侵袭性的分子机制，以及AA TNBC患者的有效治疗方案。 !

ABSTRACT! African ancestry is a risk factor for worse outcomes in triple-negative breast cancer (TNBC). Nevertheless, prognostic tools and treatment regimens are no different for African American (AA) than European American (EA) TNBC patients. Personalizing medicine for AA TNBC patients has been hindered by the fact that this population is highly admixed, so self-reported race often does not accurately reflect African genetic ancestry. There is also a dearth of studies that have analyzed tumor biomarkers and clinical outcomes using ancestry- genotyped TNBC specimens. Furthermore, few preclinical TNBC studies consider race in experimental design, and AA TNBC patients are markedly underrepresented in clinical trials. A critical barrier to progress in improving outcomes for AA TNBC patients is a lack of prognostic tools and treatment modalities that have been precisely tailored to this patient population. The broad, long-range goal of this project is to enable development of precision medicine for AA TNBC patients by advancing knowledge of the utility of nuclear HSET (nHSET) as a prognostic biomarker for AA TNBCs as well as the molecular mechanisms of racial disparities in TNBC aggressiveness and how they can be targeted. Our lab has uncovered that HSET more strongly promotes proliferation and migration of AA than EA TNBC cell lines. In addition, nHSET independently predicts poor outcomes in AA but not EA TNBCs, but this must be validated after accounting for percent African genetic ancestry in multivariable survival models and in native African TNBCs. Our proposed project has three aims. First, the proportion of African genetic ancestry will be determined for a large cohort of TNBC patient samples acquired from US, and Nigeria and we will determine if nHSET can serve as a racial disparity biomarker for the stratification of TNBCs after adjusting for their percent African genetic ancestry. Second, since HSET and MYH9 are nuclear binding partners that may assist in chromatin modification to amplify oncogenic Wnt/β-catenin signaling and MYC expression (which we have found is enriched in AA compared with EA TNBCs), we will characterize racial differences in the HSET-MYH9-MYC axis in TNBCs using patient-derived samples and correlate these racial distinctions to differences in genomic stability in TNBCs. We will employ multi-colored lenti- CRISPR-Cas9 system for knocking out key genes in this axis in AA/EA cell lines to test if the HSET-MYH9-MYC axis drives tumor aggressiveness more strongly in AA than in EA TNBCs. In Aim 3, the value of a promising commercially available HSET inhibitor will be tested in xenograft models of AA and EA TNBC patient-derived cells. Thus, this study will test the hypothesis that nHSET is a novel therapeutically actionable biomarker with greater value for AA than EA TNBC patients that drives TNBC progression and chemoresistance more strongly in AA than EA TNBC patients. The impact of this project will be to advance knowledge of prognostic biomarkers, molecular mechanisms of disease aggressiveness, and effective treatment regimens for AA TNBC patients. !