Elucidating the molecular mechanisms of PRMT5i response and resistance in LUAD and PDAC

项目摘要 蛋白质精氨酸甲基转移酶5(PRMT5)是甲基转移酶复合体的一部分，它对称地 二甲基化精氨酸残留物存在于多种蛋白质中，对许多生物过程起作用。PRMT5 已经开发了抑制剂(PRMT5i)，目前正在进行临床试验。然而，决定因素 PRMT5i的反应和耐药性在很大程度上是未知的。我将阐明PRMT5i的分子机制 肺腺癌(LUAD)和胰腺导管癌两种肿瘤类型的反应和耐药性 腺癌(PDAC)。我们的实验室已经鉴定出多个敏感的亲本(P)LUAD和PDAC系 产生了独立的抗性(R)变异体。LUAD的实验表明，R细胞都是通过 单一的机制，这是药物诱导的，不是预先存在的，反映了基因表达的戏剧性变化。我 假设这种新的基因表达特征使R细胞能够耐受PRMT5抑制并避免 增殖缺陷。我们已经确定了一个基因，stmn2，是维持PRMT5i所必需的 抵抗。在目标1中，我将剖析STMN2如何调节这一效应，并将识别和描述 通过CRISPR/Cas9 KO筛网提供额外的阻力调节器。我假设收养一个 交替的细胞状态将是肿瘤逃脱PRMT5抑制的常见机制，无论 他们的组织类型。在目标2中，我将通过询问PRMT5i耐药的机制来测试这一想法 第二种肿瘤类型是PDAC，携带与LUAD细胞相同的K-RasG12D和TP53驱动突变。总的来说， 该项目的结果将提供对实现PRMT5i的核心生物学过程的关键见解 敏感性和抵抗力，并确定它们在不同的人之间的保守程度，或对不同的人来说是唯一的 肿瘤类型。这将极大地促进对PRMT5i疗法的机理理解，因为这些药物 进入诊所。 在此期间，我将把大约70%-80%的精力集中在与研究相关的活动上， 包括阅读文献，做钳工，与我的PI、实验室团队和合作者互动，讨论我的 (和他们的)工作，并在实验室会议上陈述。剩下的20%-30%的工作将集中在 有助于我职业发展的活动，包括写作、口头演讲和指导。重要的是 麻省理工学院科赫癌症综合研究所的社区和资源提供了 特殊的科学和智力环境，促进了我的科学独立性。

Project Summary Protein arginine methyltransferase 5 (PRMT5) is part of a methyltransferase complex that symmetrically dimethylates arginine residues in a wide range of proteins responsible for many biological processes. PRMT5 inhibitors (PRMT5i) have been developed and are currently in clinical trials. However, the determinants of PRMT5i response and resistance are largely unknown. I will elucidate the molecular mechanisms of PRMT5i response and resistance in two tumor types, lung adenocarcinoma (LUAD) and pancreatic ductal adenocarcinoma (PDAC). Our lab has identified multiple sensitive parental (P) LUAD and PDAC lines and generated independent resistant (R) variants. Experiments in LUAD show that the R cells all arise through a single mechanism, which is drug-induced, not pre-existing, and reflects a dramatic shift in gene expression. I hypothesize that this new gene expression signature enables the R cells to tolerate PRMT5 inhibition and avoid proliferation defects. We have already identified one gene, Stmn2, as being essential to maintain PRMT5i resistance. In Aim 1, I will dissect how STMN2 mediates this effect, and will also identify and characterize additional regulators of resistance through CRISPR/Cas9 KO screens. I hypothesize that adoption of an alternate cell state will be the common mechanism by which tumors escape PRMT5 inhibition, irrespective of their tissue type. In Aim 2, I will test this idea by interrogating the mechanisms of PRMT5i resistance in a second tumor type, PDAC, bearing the same K-rasG12D and tp53 driver mutations as the LUAD cells. Overall, results from this project will provide key insights into the core biological processes that enable PRMT5i sensitivity and resistance, and establish the degree to which these are conserved between, or unique to, different tumor types. This will greatly advance the mechanistic understanding of PRMT5i therapies as these drugs are entering the clinic. While on this fellowship, approximately 70-80% of my effort will be focused on research related activities, including reading literature, doing benchwork, interacting with my PI, lab teams and collaborators to discuss my (and their) work, and presenting in lab meetings. The remaining 20-30% of my effort will be focused on activities that will enable my career development, including writing, oral speaking, and mentoring. Importantly, the community and resources available in the Koch Institute for Integrative Cancer Research at MIT provides an exceptional scientific and intellectual environment to advance my scientific independence.