Developing Nanotechnology to Target HMGA1 in Pancreatic Cancer

描述（由申请人提供）：本提案的主要目标是开发和测试创新的“纳米颗粒”，以便在胰腺癌的临床前模型中系统地提供新疗法（短发夹或shRNA）。胰腺导管腺癌（pdac）是一种高致死率的肿瘤，每年在世界范围内造成150万例死亡。大多数患者患有无法手术的转移性疾病，目前尚无有效的治疗方法。因此，迫切需要研究如何阻止pdac的转移进展。我们正在研究导致PDAC肿瘤进展的分子途径。我们的重点是HMGA1癌基因，该基因编码HMGA1a和HMGA1b染色质重塑蛋白。HMGA1蛋白通过改变染色质结构调节基因表达。我的实验室是第一个发现HMGA1在培养细胞和转基因小鼠中作为一种强效致癌基因起作用的。我们还发现，抑制HMGA1的表达可以阻断肿瘤和癌症干细胞的特性。我们小组和其他人最近发表的研究表明，HMGA1在90%的原发性人pdac中过表达，在侵袭性转移性肿瘤中表达水平最高，但在前体病变或正常胰腺中未表达。此外，我们发现HMGA1蛋白水平与分化状态差和生存率降低呈正相关。HMGA1的敲低阻断了多种致癌和干细胞特性，包括不依赖锚定的细胞生长、迁移、侵袭、体外三维球体形成和PDAC小鼠模型的转移进展。这些发现表明HMGA1促进PDAC的肿瘤进展。引人注目的是，我们最近的研究表明，用shRNA敲除HMGA1可以通过下调干细胞中重要的转录网络，将癌细胞从高度侵袭性的间充质样细胞重编程为非侵袭性的上皮样细胞

DESCRIPTION (provided by applicant): The primary goal of this proposal is to develop and test innovative "nanoparticles" to systemically deliver novel therapy (short hairpin or shRNA) in preclinical models for pancreatic cancer. Pancreatic ductal adenocarcinomas (PDACs) are highly lethal tumors accounting for >150,000 deaths worldwide each year. Most patients present with inoperable, metastatic disease for which there are no effective therapies. Thus, research is urgently needed to determine how to block metastatic progression in PDACs. We are studying the molecular pathways that lead to tumor progression in PDAC. Our focus is the HMGA1 oncogene, which encodes the HMGA1a and HMGA1b chromatin remodeling proteins. HMGA1 proteins regulate gene expression by altering chromatin structure. My laboratory was the first to discover that HMGA1 functions as a potent oncogene in cultured cells and transgenic mice. We also found that inhibiting HMGA1 expression blocks oncogenic and cancer stem cell properties. Recently published studies from our group and others demonstrate that HMGA1 is overexpressed in >90% of primary, human PDACs, with highest levels in invasive, metastatic tumors, but no expression in precursor lesions or normal pancreas. Moreover, we found that HMGA1 protein levels are positively correlated with poor differentiation status and decreased survival. Knock-down of HMGA1 blocks multiple oncogenic and stem cell properties, including anchorage-independent cell growth, migration, invasion, 3-dimensional sphere formation in vitro and metastatic progression in murine models of PDAC. These findings indicate that HMGA1 promotes tumor progression in PDAC. Strikingly, our recent studies show that knock-down of HMGA1 with shRNA reprograms cancer cell lines from highly invasive, mesenchymal-like cells to noninvasive, epithelial-like cells by down-regulating transcriptional networks important in stem cells and tumor progression. Knock-down of HMGA1 also enhances sensitivity to cytotoxic therapy. Our co-investigators, Drs. Hanes and Maitra, have recently pioneered novel approaches to systemically deliver plasmid nanoparticles (NPs) with effective and sustained changes in gene expression in preclinical models. Based on these exciting results, we hypothesize that: 1.) HMGA1 drives tumor progression in PDAC and could serve as a target in therapy, and, 2.) shRNA NPs will block HMGA1 expression and reprogram PDAC cells into less aggressive cells that respond to therapy. Here, we propose to test these hypotheses using our unique resources and expertise with the following Specific Aims: 1.) To determine if inducible shRNA to HMGA1 reprograms PDAC cells into noninvasive, therapy-responsive cells in our preclinical models, and, 2.) To develop NP technology to deliver HMGA1 shRNA in preclinical models of PDAC. We will test shRNA delivery using our NPs that have been optimized for delivery and efficiency by altering diameter, shape, lipid content, and other biophysical properties. If successful, our studies should provide a new paradigm for the treatment of PDAC and improve outcomes for patients.