Developing novel combination therapies for pancreatic cancer

项目摘要/摘要 胰腺导管腺癌是一种致命性疾病。对大多数患者来说，化疗 是唯一的治疗选择，而且几乎所有的患者都会因耐药疾病而复发。核苷 类似物吉西他滨是PDAC患者的一线药物和目前的治疗标准。什么时候 联合吉西他滨、厄洛替尼或NAB-紫杉醇可提高非小细胞肺癌患者的中位生存期 可切除疾病的时间分别为0.3~1.8个月。五年生存率约为6%。显然更有效 治疗是必要的。 我们建议为PDAC患者开发有效的治疗方法。我们的数据表明， 吉西他滨+BET(溴域末端外域)抑制剂JQ1和JQ1+的组合 PARP 1/2抑制剂olaparib在体外对PDAC细胞有很强的协同细胞毒作用。值得注意的是，一名飞行员 JQ1+吉西他滨的研究支持体外数据，并表明这种组合诱导了 携带患者来源的异种移植瘤(PDX)的小鼠。我们建议的这两种组合的协同效应 在表达突变KRAS的PDAC细胞中评估是明显的，KRAS突变是一种与不良相关的肿瘤细胞特征 临床结果。提示JQ1+吉西他滨和JQ1+奥拉帕利布可能包含有效成分 PDAC的治疗。 JQ1是一种新型靶向小分子，与BET蛋白的乙酰赖氨酸结合片段结合， 主要是BRD2和BRD4。这种结合抑制了BRD2/4依赖的转录产物的关联 聚集到组蛋白的乙酰化赖氨酸残基，从而抑制依赖于 这个机制。这项提案中的数据显示了JQ1诱导DNA损伤、抑制 G2细胞周期调节蛋白CDC25B和DNA修复蛋白Ku80和BRCA2在体内的表达 我们根据我们的发现和相关文献推测，JQ1诱导的DNA损伤，抑制 CDC25B和随之而来的细胞周期失调使PDAC细胞对吉西他滨敏感。我们还假设， 根据我们的发现和相关文献，JQ1诱导了Ku80和BRCA2的抑制，并随后 抑制DNA修复使PDAC肿瘤对PARP抑制剂敏感。我们建议对其疗效进行评估 和JQ1+吉西他滨(Aim 1)和JQ1+奥拉帕利(Aim 2)的协同作用机制。 体外衍生的细胞系和我们独特的体内PDX模型小组，保留了特定的生物和基因 其起源肿瘤的特征。我们还建议确定更多的蛋白质对 JQ1的细胞毒作用机制(目标3)。 拟议的工作是我们朝着发展有效的长期目标迈出的重要一步。 PDAC患者的治疗。

PROJECT SUMMARY/ABSTRACT Pancreatic ductal adenocarcinoma (PDAC) is a fatal disease. For the majority of patients chemotherapy is the only therapeutic option, and virtually all patients relapse with drug resistant disease. The nucleoside analogue gemcitabine is the frontline agent and current standard of care for patients with PDAC. When combined with gemcitabine, erlotinib or nab-paclitaxel increases median survival of patients with non- resectable disease by ~0.3 to ~1.8 months, respectively. The five-year survival is ~6%. Clearly more effective therapies are needed. We propose to develop effective therapy for patients with PDAC. Our data demonstrate that the combinations of gemcitabine + the BET (bromodomain extra-terminal domain) inhibitor JQ1 and also of JQ1 + the PARP 1/2 inhibitor olaparib induce strongly synergistic cytotoxicity in PDAC cells in vitro. Notably, a pilot study with JQ1 + gemcitabine supports in vitro data, and shows that this combination induces regressions in mice bearing patient-derived xenograft (PDX) tumors. The synergy of both combinations that we propose to evaluate was evident in PDAC cells that express mutant KRAS, a tumor cell characteristic associated with poor outcome clinically. The data suggest that JQ1 + gemcitabine and JQ1 + olaparib may comprise effective therapy for PDAC. JQ1 is a novel targeted small molecule that binds to acetyl lysine binding pockets of BET proteins, predominantly BRD2 and BRD4. This binding inhibits the association of BRD2/4-dependent transcriptional aggregates to acetylated lysine residues of histones, thereby inhibiting expression of proteins dependent on this mechanism. Data in this proposal show the novel findings that JQ1 induces DNA damage, inhibits expression of the G2 cell cycle regulator protein CDC25B and DNA repair proteins Ku80 and BRCA2 in vivo. We hypothesize, based on our findings and relevant literature, that JQ1-induced DNA damage, inhibition of CDC25B and consequent cell cycle dysregulation sensitize PDAC cells to gemcitabine. We also hypothesize, based on our findings and relevant literature, that JQ1-induced inhibition of Ku80 and BRCA2 and consequent suppression of DNA repair sensitizes PDAC tumors to PARP inhibitors. We propose to evaluate the efficacy and mechanisms of synergy of JQ1 + gemcitabine (Aim 1) and JQ1 + olaparib (Aim 2) using transfected PDX- derived cell lines in vitro and our unique panel of in vivo PDX models that retain specific biologic and genetic characteristics of their tumors of origin. We also propose to identify additional proteins that contribute to the cytotoxic mechanism of JQ1 (Aim 3). The proposed work comprises an essential step toward our long-range goal of developing effective therapy for patients with PDAC.