Elucidating the relevance of BARD1-PLK1 interaction in PDAC and response to therapy

摘要 胰腺导管腺癌(PDAC)是一种侵袭性癌症，治疗选择有限。整体而言 5年存活率只有11%，而且对更好的治疗方法的需求还没有得到满足。对于具有同源基因的患者 重组修复(HRR)缺陷肿瘤(BRCA1/2，PALB2)，多(ADP-核糖)聚合酶(PARP)抑制物 (PARPI)/基于铂的疗法提供了最佳的个性化治疗方法。然而，这种药物的功效 这些治疗通常由于固有的(HRR熟练性肿瘤)或获得性耐药而受到限制。这 强调迫切需要确定新的目标，以提高这些有希望的代理人的敏感性并扩大 可能从中受益的PDAC患者群体。我们最近发现BARD1(BRCA1- Associated-Ring-DOMAIN-1)是BRCA1的必需结合伙伴，也是HR的关键因子，在 DNA损伤条件下的PDAC细胞(Jain等人癌症(巴塞尔)6；14(7)：1848,2022)。我们发现 BARD1缺失导致的PDAC细胞(HRR熟练)对PARPI/Platinum极其敏感并增强 DNA损伤。虽然这些效应可能归因于BARD 1的S在HRR转录组中的典型作用 对BARD1沉默细胞的分析表明，BARD1对与细胞周期有关的细胞功能具有多效性， 细胞衰老和DNA复制。与这些预测一致，我们注意到BARD1强烈沉默 抑制细胞增殖，降低体外克隆形成能力，减缓PDAC细胞体内肿瘤生长， 几种细胞周期蛋白的表达减少，特别是Polo-like-Kinase-1(PLK-1)。PLK-1是一种丝氨酸 苏氨酸激酶，通过有丝分裂强烈促进细胞的发展。PLK-1在细胞中过度表达 PDAC和PLK-1活性的解除调节导致遗传不稳定，进而导致致癌 转型。我们假设PLK-1与BARD1相互作用，这种相互作用对PDAC细胞是必要的 对DNA损伤剂的反应。我们将通过两个具体目标来检验我们的假设。在目标1中，我们将 用生化方法检测PDAC细胞中BARD1和PLK-1的分子相互作用 2，我们将确定BARD‘S对PDAC细胞中PLK-1的调节是否是对DNA损伤剂的反应的驱动因素。 在小鼠模型中使用过表达系统。这个项目的首要目标是阐明 BARD1-PLK-1相互作用在PDAC中的意义及对DNA损伤剂的治疗反应这个 该项目的完成将为开发新的靶向治疗策略奠定基础。 PDAC，在未来也可以应用于其他类型的癌症。 关键词：胰腺导管腺癌、DNA损伤、细胞周期、BARD1

ABSTRACT Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer with limited treatment options. The overall 5-year survival rate is only 11% and there is an unmet need for better therapies. For patients with homologous recombination repair (HRR) deficient tumors (BRCA1/2, PALB2), poly (ADP-ribose) polymerase (PARP) inhibitor (PARPi)/platinum-based therapies offer the best-personalized treatment approach. However, the efficacy of these treatments is often limited due to inherent (HRR proficient tumors) or acquired drug resistance. This underscores a dire need to identify new targets to enhance the sensitivity of these promising agents and expand the PDAC patient population that could benefit from them. We recently discovered that BARD1 (BRCA1- Associated- Ring- Domain- 1), an obligate binding partner of BRCA1 and a key factor in HR, is upregulated in PDAC cells under DNA damage conditions (Jain et al Cancers (Basel) 6;14(7):1848, 2022). We found that deletion of BARD1 rendered PDAC cells (HRR proficient) extremely sensitive to PARPi/platinums and enhanced DNA damage. Although, these effects may be attributed to BARD1’s canonical role in HRR, transcriptome profiling of BARD1 silenced cells suggests BARD1 has pleiotropic effects on cellular functions linked to cell cycle, cellular senescence, and DNA replication. In line with these predictions, we noted that BARD1 silencing strongly reduced cell proliferation, decreased clonogenic capacity in vitro, slowed tumor growth in vivo of PDAC cells and reduced expression of several cell cycle proteins, notably Polo-Like-Kinase-1 (PLK-1). PLK-1 is a serine threonine kinase that strongly promotes the progression of cells through mitosis. PLK-1 is overexpressed in PDAC and deregulation of PLK-1 activity contributes to genetic instability, which in turn leads to oncogenic transformation. We hypothesize that PLK-1 interacts with BARD1 and this interaction is necessary for PDAC cell response to DNA damage agents. We will test our hypothesis through two specific aims. In aim 1, we will determine the molecular interaction of BARD1 and PLK-1 in PDAC cells using biochemical assays, and in aim 2, we will determine if BARD1’s regulation of PLK-1 in PDAC cells is a driver of response to DNA damage agents, using overexpression systems in a murine model. The overarching goal of this project is to elucidate the role and significance of BARD1-PLK-1 interaction in PDAC and therapy response to DNA damage agents. The completion of this project will lay the groundwork for development of novel targeted therapeutic strategies against PDAC, and in the future could be applied to other cancer types as well. Keywords: Pancreatic ductal adenocarcinoma, DNA damage, cell cycle, BARD1