Diversity Supplement to R01 Parent Grant CA186885

描述（由申请人提供）：bromodomain （BRD）和extra terminal domain （BET）家族蛋白，作为组蛋白乙酰化标记的“读者”，在3D胶原中介导胰腺导管腺癌（PDAC）细胞的生长。此外，3D胶原中的PDAC细胞通过增加高迁移率组A2 （HMGA2）的表达表现出化学耐药，HMGA2是一种调节染色质结构的结构蛋白。长期目标是帮助开发新的基于机制的靶向治疗PDAC。本应用的目的是确定BET蛋白如何介导化疗耐药并促进体内纤维化。中心假设是BET蛋白抑制将分别通过降低肿瘤干细胞群和HMGA2蛋白功能来降低PDAC肿瘤生长和增加化疗敏感性。第二个假设是BET抑制将导致PDAC肿瘤纤维化的衰减。这些假设基于强有力的初步数据，这些数据表明BET抑制剂会降低3D胶原蛋白中PDAC和星状细胞的生长。此外，用BET抑制剂治疗PDAC细胞可减少癌症干细胞数量并抑制HMGA2。其基本原理是，确定BET蛋白在体内PDAC进展中的作用和潜在机制可能有助于建立一个概念性框架，从而最终开发出新的临床有效的靶向治疗方法。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)评价抑制BET蛋白增加化疗敏感性的能力；3)评价BET蛋白的能力

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.