Novel CTD inhibitors with synthetic lethality to oncogenic Ras for cancer therapy

新型 CTD 抑制剂对致癌 Ras 具有合成杀伤力，用于癌症治疗

基本信息

批准号：
8007354
负责人：
BINGLIANG FANG
金额：
$ 31万
依托单位：
UNIVERSITY OF TX MD ANDERSON CAN CTR
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-01-01 至 2013-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8007354
关键词：
Antineoplastic Agents Apoptosis C-terminal CDK9 Protein Kinase Cancer cell line Categories Cell Line Cells Clinical Treatment Clinical Trials Colon Carcinoma Complex Cyclin-Dependent Kinases Data Development Developmental Therapeutics Program Drug Kinetics Epithelial Cells Evaluation Future Gene Mutation Genetic Transcription Goals Growth Human In Vitro Induction of Apoptosis K-ras Gene Lead Lung Lung Neoplasms Maintenance Malignant Neoplasms Malignant neoplasm of lung Malignant neoplasm of ovary Molecular Molecular Analysis Mutation National Cancer Institute New Agents Normal Cell Nude Mice Oncogenes Oncogenic Ovarian Pathway interactions Personal Communication Phenotype Phosphorylation Play Predisposition RAS genes RNA RNA Polymerase II RNA Splicing RNA polymerase II largest subunit Renal carcinoma Reporting Role Safety Screening procedure Small Interfering RNA Solid Testing Therapeutic Agents Toxic effect Yeasts analog anti-cancer therapeutic anticancer activity anticancer treatment antitumor agent cancer cell cancer therapy cell transformation cyclin T1 cytotoxic flavopiridol in vitro activity in vivo inhibitor/antagonist killings malignant breast neoplasm mutant novel novel therapeutics pre-clinical preclinical study prevent protein kinase C iota prototype public health relevance ras Proteins research clinical testing small molecule libraries tumor tumor xenograft tumorigenic

项目摘要

DESCRIPTION (provided by applicant): The oncogenic Ras proteins play critical roles in the development and maintenance of cancer phenotypes and serve as important targets for anticancer treatment. However, oncogenic Ras-targeted therapeutic agents are not yet available. Therefore, it is urgent to develop anticancer agents that can effectively eliminate Ras-mutant cancer cells. We hypothesize that agents that induce synthetic lethality in cancer cells expressing oncogenic Ras genes but not in normal isogenic cells will be valuable prototypes for developing Ras-targeted anticancer therapeutics. In searching for such agents, we screened a chemical library and identified a compound (designated oncrasin-1) that kills immortalized and tumorigenic human ovarian epithelial cells expressing oncogenic K-Ras but not their isogenic normal counterparts. Oncrasin-1 can effectively kill various lung cancer cells with K-Ras mutations. The cytotoxic effects correlated with apoptosis induction by the compounds and could be blocked by K-Ras siRNA or protein kinase C iota (PKCiota) siRNA, suggesting that Ras and/or PKCiota activities are required for oncrasin-induced apoptosis. Treatment of sensitive cancer cells with oncrasin-1, -60, or -231 led to suppression of the phosphorylation of the C-terminal domain (CTD) of the largest subunit of RNA polymerase II, whish is consistent with previous reports that the continuous activity of RNA polymerase II is required to prevent oncogene-induced apoptosis in transformed cells and that mutations compromising CTD function is synthetically lethal with elevated levels of Ras activity in yeast. Treatment with oncrasin-1 also led to co-aggregation of PKCiota and splicing factors in megaspliceosomes and to disruption of the interaction between PKCiota and CDK9/cyclin T1 complex, which phosphorylates the CTD. Thus, we hypothesized that oncrasin compounds are a novel class of CTD inhibitors with selective anticancer activity. The in vivo administration of oncrasin-1 suppressed the growth of human lung tumor xenografts by >70% and prolonged the survival of tumor-bearing nude mice without causing detectable toxicity. Testing some of those analogues on NCI-60 cell lines showed that oncrasins are active against several cell lines derived from lung, colon, breast, ovary, and kidney cancers and oncrasin-60 lies outside the category of adequately studied classes of antitumor agents, indicating its novel anticancer mechanisms. Thus, oncrasin compounds are potentially a novel class of CTD inhibitors that are synthetically lethal to cancers with increased Ras/PKCiota activity. However, in vivo evaluation of the pharmacokinetics, antitumor efficacy, and safety of oncrasin compounds is necessary before they can be evaluated clinically. The goal of this proposal is to determine anti- lung cancer activity of the most active analogues by evaluating their in vitro activities in several lung cancer cell lines with or without Ras gene mutations, their pharmacokinetics, and their in vivo activity and toxicity. The proposed studies will provide solid preclinical data for possible clinical evaluation of oncrasin compounds and may lead to the development of new therapeutic agents that are useful for the treatment of lung cancers. PUBLIC HEALTH RELEVANCE: We have identified a group of new agents that are selectively toxic to cancer cells with increased Ras activity but not to normal cells. The molecular characterization revealed those compounds inhibit the phosphorylation and function of C-terminal domain of the largest subunit of RNA polymerase II. The goal of this proposal is to perform pre-clinical studies on their antitumor activities in lung cancer cells in vitro and in vivo that are required for future clinical trials.

描述（由申请人提供）：致癌Ras蛋白在癌症表型的发展和维持中发挥关键作用，并作为抗癌治疗的重要靶标。然而，目前还没有针对致癌 Ras 的治疗药物。因此，迫切需要开发能够有效消灭Ras突变癌细胞的抗癌药物。我们假设，在表达致癌 Ras 基因的癌细胞中诱导合成致死作用但在正常同基因细胞中不诱导合成致死作用的药物将成为开发 Ras 靶向抗癌疗法的有价值的原型。在寻找此类药物的过程中，我们筛选了一个化学文库，并鉴定了一种化合物（命名为 oncrasin-1），它可以杀死表达致癌 K-Ras 的永生化和致瘤性人卵巢上皮细胞，但不能杀死表达致癌 K-Ras 的同基因正常对应物。 Oncrasin-1可以有效杀灭具有K-Ras突变的多种肺癌细胞。细胞毒性作用与化合物诱导细胞凋亡相关，并且可以被 K-Ras siRNA 或蛋白激酶 C iota (PKCiota) siRNA 阻断，表明 Ras 和/或 PKCiota 活性是 oncrasin 诱导细胞凋亡所必需的。用 oncrasin-1、-60 或 -231 处理敏感癌细胞会抑制 RNA 聚合酶 II 最大亚基的 C 末端结构域 (CTD) 的磷酸化，这与之前的报道一致，即持续活性RNA 聚合酶 II 是防止转化细胞中癌基因诱导的细胞凋亡所必需的，并且随着酵母中 Ras 活性水平的升高，损害 CTD 功能的突变具有综合致死性。 Oncrasin-1 治疗还导致 PKCiota 和巨剪接体中的剪接因子共聚集，并破坏 PKCiota 和 CDK9/细胞周期蛋白 T1 复合物之间的相互作用，从而磷酸化 CTD。因此，我们假设 oncrasin 化合物是一类具有选择性抗癌活性的新型 CTD 抑制剂。体内施用 oncrasin-1 可抑制人肺肿瘤异种移植物的生长超过 70%，并延长荷瘤裸鼠的生存期，且不会引起可检测到的毒性。在 NCI-60 细胞系上测试其中一些类似物表明，oncrasin 对来自肺癌、结肠癌、乳腺癌、卵巢癌和肾癌的几种细胞系具有活性，而 oncrasin-60 不属于经过充分研究的抗肿瘤药物类别，这表明其新颖的抗癌机制。因此，oncrasin 化合物可能是一类新型 CTD 抑制剂，其对 Ras/PKCiota 活性增加的癌症具有合成致死性。然而，在进行临床评估之前，有必要对oncrasin化合物的药代动力学、抗肿瘤功效和安全性进行体内评估。该提案的目的是通过评估最活跃类似物在有或没有Ras基因突变的几种肺癌细胞系中的体外活性、它们的药代动力学以及它们的体内活性和毒性，来确定它们的抗肺癌活性。拟议的研究将为 Oncrasin 化合物的可能临床评估提供可靠的临床前数据，并可能导致可用于治疗肺癌的新治疗药物的开发。公共健康相关性：我们已经确定了一组新药物，它们对 Ras 活性增加的癌细胞具有选择性毒性，但对正常细胞没有毒性。分子表征表明这些化合物抑制 RNA 聚合酶 II 最大亚基 C 端结构域的磷酸化和功能。该提案的目标是对它们在体外和体内肺癌细胞中的抗肿瘤活性进行临床前研究，这是未来临床试验所需的。