A novel more effective genotoxic therapy for ovarian cancer

高级别浆液性卵巢癌（HGSOC）是最致命的妇科恶性肿瘤。超过80% 的HGSOC患者在一线标准治疗后复发，完全和持久的反应是罕见的。 需要改善竞争性肿瘤消退和预防复发的疗法。我们的目标是i） 确定哪些卵巢癌遗传子集将受益于新的更有效的遗传靶向 使用来自我们的原代肿瘤培养物、患者来源的异种移植物模型和人肿瘤样品进行治疗。 临床试验，ii）通过遗传验证确定获得性抗性的机制。 我们已经确定了一种新的和高活性的基因毒性治疗，通过共抑制聚ADP核糖 聚合酶（PARP）和ATR检查点激酶。PARP抑制与ATR抑制的组合（PARPi-1） ATRi）协同作用以特异性靶向并杀死携带常见HGSOC相关改变的HGSOC， 例如同源重组（HR）缺陷和细胞周期蛋白E过表达。我们的初步研究显示 PARPi-ATRi组合在杀死具有这些改变和原因的HGSOC细胞方面特别有效， HR缺陷和细胞周期蛋白E过表达的HGSOC患者来源的异种移植物（PDX）的消退。 结果刺激了PARPi-ATRi组合在复发性HGSOC（HGSOC患者）中的临床试验 由本提案的PI领导。这将是第一项评估PAPRi-ATRi联合治疗的试验。 卵巢癌 在这里，我们建议验证体外研究结果，并扩大使用我们的PDX模型，一个可靠的HGSOC 替代物，以测试这种新型PARPi-ATRi组合在杀死HGSOC中的有效性， 过度表达细胞周期蛋白E或获得PARPi抗性，这些共同导致HGSOC的大多数死亡。 我们的PARPi-ATRi治疗复发性HGSOC的临床试验将与 扩展的临床前小鼠研究。这将使我们能够将预测性生物标志物（HR缺乏和 细胞周期蛋白E过表达）的反应和潜在的抗性机制（例如，BRCA回复突变）。 这种PARPi-ATRi联合治疗是有希望的;然而，这种治疗导致肿瘤消退， 最初在化疗耐药的细胞周期蛋白E过表达肿瘤中，但最终发展为获得性耐药。使用 基因组学和蛋白质组学，我们将整合在PAPRi-ATRi耐药和敏感基因中发现的改变。 使用来自临床试验的患者样本进行PDX，以开发候选池列表。候选基因相关 将通过优先考虑在基因和蛋白质水平上发现的改变来改进抗性， 可下药的顶级候选人将使用靶向CRISPR敲低方法进行体外验证。 定义反应和耐药的标志物将有助于对患者人群进行分层，优化治疗策略， 并基于HGSOC癌症遗传学确定未来治疗的新靶点。

High-grade serous ovarian cancer (HGSOC) is the most lethal gynecological malignancy. More than 80% of HGSOC patients recur after frontline standard therapy, and complete and durable responses are rare. Therapies that improve compete tumor regression and prevent relapse are needed. Our GOALS are to i) identify which ovarian cancer genetic subsets will benefit from a new more effective genetically targeted therapy using primary tumor cultures, patient-derived xenograft models and human tumor samples from our clinical trial, ii) identify mechanisms of acquired resistance with genetic validation. We have identified a novel and highly active genotoxic therapy by co-inhibiting poly-ADP ribose polymerase (PARP) and ATR checkpoint kinase. Combination PARP inhibition with ATR inhibition (PARPi- ATRi) synergizes to specifically target and kill HGSOCs harboring common HGSOC-associated alterations, e.g. homologous recombination (HR) deficiency and Cyclin E overexpression. Our preliminary studies show that PARPi-ATRi in combination is especially effective in killing HGSOC cells with these alterations and causes regression of HR-deficient and Cyclin E overexpressing HGSOC patient-derived xenografts (PDXs).These results have stimulated a clinical trial of PARPi-ATRi combination in recurrent HGSOC (unselected patient population) to be led by the PI of this proposal. This will be the first trial evaluating PAPRi-ATRi combination in ovarian cancer. Here, we propose to validate in vitro findings and expand the use of our PDX model, a reliable HGSOC surrogate, to test the effectiveness of this novel PARPi-ATRi combination in killing HGSOCs that either overexpress Cyclin E-or have acquired PARPi-resistance, which together cause most deaths from HGSOC. Our clinical trial of PARPi-ATRi for treatment of recurrent HGSOC will be performed in parallel with the expanded preclinical mouse studies. This will allow us to correlate predictive biomarkers (HR-deficiency and Cyclin E overexpression) of response and potential resistance mechanisms (e.g., BRCA reversion mutations). This PARPi-ATRi combination therapy is promising; however, this treatment causes tumor regression initially in chemo-resistant Cyclin E-overexpressing tumors but acquired resistance ultimately develops. Using genomic and proteomics, we will integrate alterations discovered in the PAPRi-ATRi-resistant and sensitive PDXs with patient samples from the clinical trial to develop a candidate pool list. Candidate genes associated with resistance will be refined by prioritizing alterations found at both the gene and protein level and that are druggable. The top candidates will be validated in vitro using a targeted CRISPR knock-down approach. Defining markers of response and resistance will help stratify patient populations, optimize treatment strategies and identify new targets for future therapeutics based on HGSOC cancer genetics.