The role of PARP inhibitor target engagement in breast cancer

描述（由申请人提供）：该提案的主要目标是开发新的成像方法，以了解体内药物活性的复杂生物学。具体来说，我会 开发和优化荧光偏振显微镜方法，以在小鼠肿瘤模型中以细胞分辨率成像癌症药物的靶点接合。这项技术，题为竞争多光子荧光各向异性显微镜（compMFAM），使成像的未标记的药物靶点通过竞争与荧光标记的药物相同的目标。当药物被证明无效时，测量靶点参与可以深入了解治疗失败的机制。这些数据可用于确定失败是否源于药物分布效率低下或靶点无法影响细胞。候选人J. Matt Dubach博士在用于难以测量目标的荧光成像的新型传感器开发方面拥有丰富的经验。候选人的长期目标是开发新的成像方法，以更好地了解生物系统中细胞水平的癌症。拟议的工作将在马萨诸塞州总医院和哈佛医学院的系统生物学中心进行，由Ralph Weissleder医学博士和Tim Mitchison博士指导。导师团队将在独立之路的导师阶段协助候选人的发展，并帮助候选人过渡到独立研究人员。该提案的具体目标集中在两个领域：成像系统的技术开发;以及通过小鼠模型测量PARP靶点参与治疗乳腺癌的作用的生物学应用。目前有几种有前途的PARP抑制剂正在临床试验中用于各种癌症。主要是由于 由于BRCA突变在乳腺癌中的高流行率，PARP抑制剂目前被探索作为三阴性乳腺癌的单药治疗。初步的可行性实验表明，这是一种有效的方法来定量测量药物在体内的目标接合。在该提议中有两个具体目的：1）用于测量细胞水平靶标接合的双组分MFAM技术;和2）确定靶标接合如何控制成功的PARP抑制剂治疗。目标1将在导师团队的指导下完成，而目标2将作为独立调查员执行。该提案的成功完成将提供对PARP靶点接合如何在成功和不成功的治疗中控制细胞应答的深入了解，同时提供一种可推广的方法来研究几乎任何抑制剂药物类别的靶点接合。

DESCRIPTION (provided by applicant): The broad goal of this proposal is to develop new imaging approaches to understand the complex biology of drug activity in vivo. Specifically, I will develop and optimize a fluorescence polarization microscopy approach to image target engagement of cancer drugs at cellular resolution in mouse tumor models. This technique, entitled competition multiphoton fluorescence anisotropy microscopy (compMFAM), enables imaging of unlabeled drug target engagement through competition with fluorescently labeled drug of the same target. Measuring target engagement provides insight into the mechanism of treatment failure when a drug proves ineffective. These data can be used to determine if failure arises from inefficient drug distribution or inability of the target to effect the cell. The candidte, J. Matt Dubach, PhD, has extensive experience in novel sensor development for fluorescent imaging of difficult to measure targets. The long term goal of the candidate is to develop novel imaging approaches to better understand cancer at the cellular level in biological systems. The proposed work will be conducted at the Center for Systems Biology at Massachusetts General Hospital and Harvard Medical School under the mentorship of Ralph Weissleder, MD, PhD and Tim Mitchison, PhD. The mentorship team will assist in the candidate's development during the mentored phase of the pathway to independence and help the candidate transition into an independent researcher. The specific aims of this proposal focus on two areas: technological development of the imaging system; and biological applications to measure the role of PARP target engagement in treatment of breast cancer through mouse models. There are several promising PARP inhibitors currently in clinical trials for a variety of cancers. Largely due to the high prevalence of BRCA mutations in breast cancer, PARP inhibitors are currently be explored as single agent treatment in triple negative breast cancer. Preliminary feasibility experiments demonstrate that this is a valid approach to quantitatively measure target engagement of drug in vivo. There are two specific aims in this proposal: 1) Validate compMFAM technique to measure cellular level target engagement; and 2) Determine how target engagement governs successful PARP inhibitor treatment. Aim 1 will be accomplished under the mentorship team, while Aim 2 will be performed as an independent investigator. Successful completion of this proposal would provide insight into how PARP target engagement governs cellular response in successful and unsuccessful treatment while providing a generalizable approach to study target engagement of nearly any inhibitor drug class.