Project 1: Targeting Metastatic Prostate Cancer Patients with Biallelic Loss of CDK12

随着过去几年下一代测序技术的广泛集成， 全面的基因组研究表明，前列腺癌可以分为不同的分子。 子类型。识别这些亚型和致病的分子驱动因素提供了一个机会 设计合理的精确肿瘤学治疗方法。为此，我们最近确定了和 描述了一种新的前列腺癌分子亚型，其典型特征是CDK12的双等位基因失活 它在转移性去势抵抗前列腺癌(MCRPC)病例中富含。CDK12-突变型前列腺 癌症表现出与其他前列腺癌亚型不同的基因组不稳定模式，包括同源前列腺癌 与焦点串联复制(FTD)相关的重组和错配修复缺陷 表型。重要的是，CDK12-FTDS由于基因融合增加而导致新抗原负荷增加，并且 这反映在主动的免疫反应和增加的T细胞在肿瘤微环境中的运输。 因此，我们队列中mCRPC患者的初步结果表明，他们可能有更高的 对免疫检查点封锁的反应可能性。因此，我们假设CDK12的失活 结果产生了一类免疫原性的mCRPC，可能受益于免疫导向治疗。这一假设 将通过以下具体目标进行探讨： 目的1：确定CDK12缺失与前列腺癌生物学的功能相关性，并鉴定合成致死物 目标。这一目标的实验将集中在体外方法、生物信息学分析和CRISPR筛查上 为了研究CDK12缺失如何影响前列腺癌的发病机制并促使 免疫基因组表型。 目的：研究CDK12消融对体内前列腺癌生长和免疫应答的影响。我们会 建立几种CDK12缺失的小鼠前列腺模型以直接评估CDK12在前列腺中的作用 肿瘤发生和对免疫检查点阻断的反应。 目的3：在免疫检查点阻断的第一次临床试验中确定反应的分子决定因素 CDK12突变的mCPRC患者。使用我们的nivolumab和ipilimumab的第二阶段试验(IMPACT)的样本 在CDK12突变的患者中，我们将分析免疫反应的变化，并确定肿瘤的内在特征 反应的生物标志物。 总之，这些目标的完成将确定CDK12在前列腺癌发生中的作用并评估精确度 最近发现的前列腺癌亚型的肿瘤学治疗方法。

With the wide-spread integration of next-generation sequencing technology over the past several years, comprehensive genomic studies have shown that prostate cancers can be classified into different molecular subtypes. Identification of these subtypes and molecular drivers of pathogenesis represents an opportunity to design rational precision oncology approaches for treatment. To this end, we have recently identified and characterized a novel molecular subtype of prostate cancer typified by biallelic inactivation of CDK12 and shown that it is enriched in cases of metastatic castration-resistant prostate cancer (mCRPC). CDK12-mutant prostate cancers exhibit a distinct genomic instability pattern from other prostate cancer subtypes, including homologous recombination and mismatch repair-deficient, that is associated with a focal tandem duplication (FTD) phenotype. Importantly, CDK12-FTDs lead to an elevated neoantigen burden from increased gene fusions, and this is mirrored by an active immune response and increased T cell trafficking in the tumor microenvironment. Accordingly, preliminary results from mCRPC patients in our cohort suggest that they may have a higher likelihood of response to immune checkpoint blockade. We, therefore, hypothesize that inactivation of CDK12 results in an immunogenic class of mCRPC that may benefit from immune-directed therapies. This hypothesis will be explored through the following Specific Aims: Aim 1: Define the functional relevance of CDK12 loss to prostate cancer biology and identify synthetic lethal targets. Experiments in this Aim will focus on in vitro methods, bioinformatics analyses, and a CRISPR screen to examine how CDK12 loss impacts prostate cancer pathogenesis and drives the emergence of an immunogenomic phenotype. Aim 2: Determine the impact of Cdk12 ablation on prostate tumor growth and immune response in vivo. We will generate several Cdk12-null mouse prostate models to directly evaluate the role of Cdk12 in prostate tumorigenesis and response to immune checkpoint blockade. Aim 3: Identify molecular determinants of response in the first clinical trials of immune checkpoint blockade for CDK12-mutant mCPRC patients. Using samples from our Phase II trial (IMPACT) of nivolumab and ipilimumab in CDK12-mutant patients, we will analyze changes in the immune response and determine tumor-intrinsic biomarkers of response. Together, completion of these Aims will define the role of CDK12 in prostate tumorigenesis and assess precision oncology approaches for this recently identified subtype of prostate cancer.