Diversity Supplement to R01 Parent Grant CA186885

描述（由申请人提供）：蛋白质的溴结构域（BRD）和额外末端结构域（BET）家族，作为组蛋白乙酰化标记的"阅读器"，介导胰腺导管腺癌（PDAC）细胞在3D胶原中的生长。此外，3D胶原蛋白中的PDAC细胞通过增加高迁移率族A2（HMGA2）（一种调节染色质结构的结构蛋白）的表达而表现出化学抗性。长期目标是帮助开发新的基于机制的靶向治疗PDAC。本申请的目的是确定BET蛋白如何介导化学抗性并促进体内纤维化。中心假设是BET蛋白抑制将分别通过降低癌症干细胞群体和HMGA 2蛋白功能来降低PDAC肿瘤生长并增加化学敏感性。第二个假设是BET抑制将导致PDAC肿瘤中纤维化的减弱。这些假设是基于强有力的初步数据，表明BET抑制剂减少PDAC和星状细胞在3D胶原中的生长。此外，用BET抑制剂处理PDAC细胞减少了癌症干细胞群体并抑制HMGA2。其基本原理是，BET蛋白在体内PDAC进展中的作用和潜在机制的确定可能实质上有助于概念框架，从而最终可以开发新的临床有效的靶向治疗。提出了三个具体目标：1）确定BET蛋白在体内PDAC进展中的作用; 2）评价BET蛋白抑制增加化疗敏感性的能力;和3）评价BET蛋白抑制PDAC进展的能力。 抑制以减弱纤维化。在第一个目标下，将在小鼠模型中确定BET抑制剂对PDAC进展的影响。此外，还将评估BET抑制剂减少体内PDAC干细胞群的程度。此外，将确定与BRD4 siRNA偶联的金纳米颗粒（Au-NP）抑制肿瘤生长的能力。对于第二个目的，将在3D胶原蛋白和小鼠模型中评价BET抑制剂增加化疗功效的能力。此外，还将评估BET蛋白在DNA损伤反应中的作用以及HMGA 2对BET蛋白调节化疗耐药性的贡献。在第三个目标中，BET抑制剂调节星状细胞活化和胶原蛋白产生的机制将被确定。还将评估BET抑制剂和用BRD4 siRNA官能化的Au-NP在小鼠模型中减弱纤维化的有效性。这项研究是创新的，因为它利用了胰腺癌的复杂模型，包括体外器官型培养和体内原位和转基因小鼠模型，以确定BET蛋白在PDAC进展中的作用。另一个创新是使用用siRNA功能化的Au-NP来下调模型系统中的BRD4表达。这项拟议的研究意义重大，因为它有望为BET抑制剂在PDAC中的持续开发和未来临床试验提供强有力的科学依据。

DESCRIPTION (provided by applicant): The bromodomain (BRD) and extra terminal domain (BET) family of proteins, which function as 'readers' of histone acetylation marks, mediate growth of pancreatic ductal adenocarcinoma (PDAC) cells in 3D collagen. Additionally, PDAC cells in 3D collagen demonstrate chemoresistance through increased expression of high mobility group A2 (HMGA2), an architectural protein that regulates chromatin structure. The long-term goal is to help develop novel mechanism-based targeted therapies for the treatment of PDAC. The objective in this application is to determine how BET proteins mediate chemoresistance and contribute to fibrosis in vivo. The central hypothesis is that BET protein inhibition will decrease PDAC tumor growth and increase chemosensitivity by decreasing the cancer stem cell population and HMGA2 protein function, respectively. A second hypothesis is that BET inhibition will lead to an attenuation of fibrosis in PDAC tumors. These hypotheses are based on strong preliminary data demonstrating that BET inhibitors decrease growth of PDAC and stellate cells in 3D collagen. In addition, treatment of PDAC cells with BET inhibitors decreases cancer stem cell population and represses HMGA2. The rationale is that a determination of the role and underlying mechanism of BET proteins in PDAC progression in vivo is likely to contribute substantively to a conceptual framework whereby new clinically effective targeted therapies can ultimately be developed. Three specific aims are proposed: 1) Determine the role of BET proteins in PDAC progression in vivo; 2) Evaluate the ability of BET protein inhibition to increase chemotherapy sensitivity; and 3) Evaluate the ability of BET protein inhibition to attenuate fibrosis. Under the first aim, the effect of BET inhibitors on PDAC progression will be determined in mouse models. Further, the extent to which BET inhibitors decrease PDAC stem cell population in vivo will be evaluated. Also, the ability of gold nanoparticles (Au-NPs) coupled with BRD4 siRNA to inhibit tumor growth will be determined. For the second aim, the ability of BET inhibitors to increase chemotherapy efficacy will be evaluated in 3D collagen and in mouse models. Additionally, the role of BET proteins in DNA damage response and the contribution of HMGA2 to BET protein regulation of chemoresistance will be assessed. In the third aim, the mechanism by which BET inhibitors regulate stellate cell activation and collagen production will be determined. The effectiveness of BET inhibitors and Au-NPs functionalized with BRD4 siRNA to attenuate fibrosis in mouse models will also be evaluated. The research proposed is innovative because it utilizes complex models of pancreatic cancer, including in vitro organotypic cultures and in vivo orthotopic and transgenic mouse models to determine the role of BET proteins in PDAC progression. An additional innovation is the use of Au-NPs functionalized with siRNAs to downregulate BRD4 expression in the model systems. This proposed research is significant because it is expected to provide strong scientific justification for the continued development and future clinical trials of BET inhibitors in PDAC.