A novel regimen to target both pancreatic cancer K-ras and antiapoptotic proteins

描述（由申请人提供）：该R 03试点项目的目标是证明一种创新的联合治疗方案的概念证明，该方案旨在靶向具有K-ras突变和一种或多种抗凋亡蛋白异常表达的胰腺癌。胰腺癌中K-ras致癌突变和主要抗凋亡蛋白（例如生存素、Mcl-1、XIAP、cIAP 2）的异常表达在很大程度上促进了胰腺癌的发展和侵袭性（治疗抗性、转移和复发）。在>90%的胰腺癌患者中观察到K-ras功能获得性突变。突变的K-ras基因沉默诱导细胞凋亡并抑制胰腺癌细胞生长、侵袭性、恶性肿瘤形成和异种移植肿瘤生长。然而，对于胰腺癌K-ras突变没有有效的靶向治疗。使用K-ras突变细胞与正常细胞的新筛选方法，从药用植物Amoora rohituka中鉴定出15种化学成分，并使用半合成方法从15种命中物中产生了50多种衍生物。然后使用K-ras突变细胞与正常细胞重新筛选这些化合物。AMR-Me和AMR-MeOAc被鉴定为选择性地针对K-ras突变细胞的最有效的化合物。我们之前的研究表明，AMR-Me靶向K-ras通路，每天3 mg/kg，持续28天的小鼠治疗没有显示出明显的毒性，同时延长了白血病小鼠的存活期。我们计划将联合收割机AMR-MeOAc（最佳选择性）与我们的新型化合物FL 118（选择性抑制生存素、Mcl-1、XIAP和cIAP 2）组合，以测试这种新型组合靶向治疗方案。先前已经显示，与单独的任一种单一药剂相比，K-ras沉默与吉西他滨的组合显著减少小鼠中的肿瘤体积。因此，我们假设，与单独使用任何一种药物的抑制相比，使用新型药物AMR-MeOAc和FL 118抑制突变的K-ras和主要抗凋亡蛋白将导致显著增强的凋亡诱导和胰腺癌细胞和肿瘤生长的抑制。该项目提出了以下三个具体目标。目标1：在存在或不存在低剂量FL 118的情况下，确定AMR-MeOAc对胰腺癌细胞生长、凋亡和相关信号通路中蛋白质调节的功效。目标二：使用人胰腺癌细胞系来源的异种移植模型，在存在或不存在低剂量FL 118的情况下确定AMR-MeOAc的功效。目标3：确定在存在或不存在低剂量FL 118的情况下AMR-MeOAc对直接来源于患者胰腺癌组织的异种移植物的功效。K-ras功能获得性突变和一种或多种抗凋亡蛋白（Survivin、Mcl-1、XIAP、cIAP 2）异常表达的胰腺癌是一种难以治疗的肿瘤，本项目可能开发一种新的靶向联合治疗策略，以有效控制这种具有挑战性和难治性的癌症。

DESCRIPTION (provided by applicant): The goal of this R03 pilot project is to demonstrate a proof of concept for an innovative combination treatment regimen designed to target pancreatic cancer with K-ras mutations and aberrant expression of one or more antiapoptotic proteins. K-ras oncogenic mutations and aberrant expression of major antiapoptotic proteins (e.g. survivin, Mcl-1, XIAP, cIAP2) in pancreatic cancer heavily contribute to pancreatic cancer development and aggressiveness (treatment resistance, metastasis, and relapse). Gain-of-K-ras-function mutations is observed in >90% of pancreatic cancer patients. Genetic silencing of mutated K-ras induces apoptosis and inhibits pancreatic cancer cell growth, invasiveness, malignant tumor formation, and xenograft tumor growth. However, there are no effective targeted therapies available for pancreatic cancer K-ras mutations. Using a novel screening approach with K-ras mutant cells versus normal cells, fifteen chemical constituents from the medicinal plant Amoora rohituka were identified, and over 50 derivatives were generated using semi-synthetic approaches from the 15 hits. These compounds were then rescreened using K-ras mutant cells versus normal cells. AMR-Me and AMR-MeOAc were identified as the most potent compounds selectively against the K-ras mutant cells. Our previous studies indicated that AMR-Me targets the K-ras pathway, and that 3 mg/kg daily for 28-day treatment of mice shows no clear toxicity, while it extends leukemia mouse survival. We plan to combine AMR-MeOAc (best selectivity) with our novel compound, FL118, which selectively inhibits survivin, Mcl-1, XIAP, and cIAP2, for testing this novel combinational-targeted treatment regimen. It has previously been shown that combination of K-ras silencing with gemcitabine dramatically reduces tumor volumes in mice compared with either single agent alone. Therefore, we hypothesize that inhibition of both mutated K-ras and the major antiapoptotic proteins with the novel agents AMR-MeOAc and FL118 would lead to a strikingly enhanced induction of apoptosis and inhibition of pancreatic cancer cell and tumor growth than the inhibition from either agent alone. The following three specific aims are proposed in this project. Aim 1: Determine the efficacy of AMR-MeOAc in the presence or absence of low dose FL118 on pancreatic cancer cell growth, apoptosis, and modulation of proteins in the relevant signaling pathways. Aim 2: Determine the efficacy of AMR-MeOAc in the presence or absence of low dose FL118 using human pancreatic cancer cell line-derived xenograft models. Aim 3: Determine the efficacy of AMR-MeOAc in the presence or absence of low dose FL118 against xenografts directly derived from patient pancreatic cancer tissues. Pancreatic cancer with K-ras gain-of-function mutations and aberrant expression of one or more antiapoptotic proteins (survivin, Mcl-1, XIAP, cIAP2) is hard to treat. This project may develop a novel and targeted combination strategy to effectively control this challenging and difficult-to-treat cancer.