Defining PARP Inhibitor Response and Resistance in Prostate Cancer

项目摘要/摘要 这一K01奖项的目的是促进艾伦·隆巴德博士发展成为一名独立的 前列腺癌研究人员。拟议的项目将扩大对PARP抑制的理解 前列腺癌的治疗和首席研究员隆巴德博士将推出一条独立的生产线 在学习方面。此外，还描述了密集的指导和集中的培训目标，以促进隆巴德博士 从被辅导者过渡到独立调查者。晚期前列腺癌仍然是一种不治之症。 PARP抑制剂(PARPI)，如rucaparib和olaparib，是最近批准的一种令人兴奋的新疗法 对一小部分病人的治疗。据认为，PARPI的功能是通过导致DNA损伤和 加剧同源重组缺陷以引起合成致死性。虽然PARP抑制承诺 为了显著改善前列腺癌患者的管理，关于它们的使用仍然存在问题 包括1)PARP抑制剂敏感的前列腺肿瘤细胞对治疗有何反应以及2)什么 这些机制最终会导致PARP抑制剂产生耐药性。为了解决这些问题，两种olaparib 使用PARPI敏感的LNCaP建立了耐药前列腺癌模型LN-Olip R和2B-Olip R 和C4-2B细胞株。Olip R模型显示出对奥拉帕利的强大耐药性和对 其他临床相关的PARPI。初步数据表明，PARPI敏感细胞对治疗没有反应 不仅通过细胞死亡，还通过G2/M期阻滞，p21依赖的衰老，这可能提供一个 存活细胞库，可逃避PARPI细胞毒性并产生耐药性。PARPI诱导 衰老导致衰老相关分泌表型(SASP)的激活，从而促进 维持衰老和细胞活力。有趣的是，OLAPR细胞1)不增加p21的表达， 2)不抑制G2/M期，3)对PARP抑制反应钝化衰老，表明抗性是 基于细胞周期检查点覆盖，数据表明可以通过抑制 CDK1。这些观察结果导致假设PARPI诱导的p21依赖的衰老是 通过细胞周期检查点覆盖克服耐药性。在目标1中，研究将确定是否 衰老是对PARPI的普遍反应，并机械地定义了p21在这一过程中的重要性 表型。在目标2中，将对PARPI诱导的SASP进行表征，重点是 了解IGFBP3的作用，这是一个已知的SASP因素。最后，目标3将进一步发展战略 靶向CDK1治疗PARPI耐药前列腺癌 单元格覆盖G2/M检查点。加州大学戴维斯分校的环境充满了所有资源、专业知识、 教职员工需要促进隆巴德博士的发展和完成拟议中的研究。Dr。 隆巴德将接受一些培训活动，包括蛋白质组学、基因组学、疾病等方面的讲习班。 建模和授权写作，并将由一个专家团队指导，指导他走向独立。

PROJECT SUMMARY/ABSTRACT The objective of this K01 award is to promote the development of Dr. Alan Lombard into an independent prostate cancer researcher. The proposed project will expand understanding of PARP inhibition for the treatment of prostate cancer and position Dr. Lombard, the principal investigator, to launch an independent line of study. Furthermore, intense mentoring and focused training goals are described to facilitate Dr. Lombard's transition from mentee to independent investigator. Advanced prostate cancer remains an incurable disease. PARP inhibitors (PARPi), such as rucaparib and olaparib, are an exciting new therapy recently approved for the treatment of a subset of patients. It is thought that PARPi's function by causing DNA damage and exacerbating homologous recombination deficiency to elicit synthetic lethality. While PARP inhibition promises to significantly improve the management of prostate cancer patients, questions remain regarding their use including 1) how do PARP inhibitor sensitive prostate tumor cells respond to treatment and 2) what mechanisms will ultimately give rise to PARP inhibitor resistance. To address these questions, two olaparib resistant prostate cancer models were developed, LN-OlapR and 2B-OlapR, using the PARPi sensitive LNCaP and C4-2B cell lines, respectively. OlapR models exhibit robust resistance to olaparib and cross-resistance to other clinically relevant PARPi's. Preliminary data suggests that PARPi sensitive cells respond to treatment not only through cell death but also through G2/M arrested, p21 dependent senescence, which may provide a repository of surviving cells that evade PARPi cytotoxicity and give rise to resistance. PARPi induced senescence leads to activation of the senescence associated secretory phenotype (SASP) which promotes maintenance of senescence and cellular viability. Interestingly, OlapR cells 1) do not increase p21 expression, 2) do not G2/M arrest, and 3) blunt senescence in response to PARP inhibition, suggesting that resistance is predicated upon cell cycle checkpoint override, which data suggests can be targeted through inhibition of CDK1. The observations lead to the hypothesis that PARPi induced p21 dependent senescence is overcome in resistance through cell cycle checkpoint override. In Aim 1, studies will determine whether senescence is a general response to PARPi's and mechanistically define the importance of p21 in this phenotype. In Aim 2, characterization of the PARPi induced SASP will be undertaken, with emphasis on understanding the role of IGFBP3, a known SASP factor. Lastly, Aim 3 will further develop the strategy of targeting CDK1 for the treatment of PARPi resistant prostate cancer and seek to understand how resistant cells override the G2/M checkpoint. The environment at UC Davis is replete with all the resources, expertise, and faculty needed to foster the development of Dr. Lombard and completion of proposed studies. Dr. Lombard will undergo a number of training activities, including workshops in proteomics, genomics, disease modeling, and grant writing, and will be mentored by an expert team to guide him to independence.