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

• 批准号: 8197944
• 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
• 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/8197944
• 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

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）：致癌性RAS蛋白在癌症表型的发展和维持中起关键作用，并作为抗癌治疗的重要靶标。但是，尚未提供致癌性RAS靶向的治疗剂。因此，迫切需要开发可以有效消除Ras突变癌细胞的抗癌药。我们假设诱导表达致癌性RAS基因但在正常同生细胞中的癌细胞中诱导合成致死性的药物对于发展为RAS靶向RAS的抗癌疗法将是有价值的原型。在寻找此类药物时，我们筛选了一个化学文库，并确定了一种化合物（指定的卵菌素1），该化合物杀死了表达致癌K-RAS的永生和肿瘤性人类卵巢上皮细胞，但没有其等源性正常对应物。 oncrasin-1可以有效地用K-RAS突变杀死各种肺癌细胞。与化合物诱导的凋亡诱导相关的细胞毒性作用，可能会被K-Ras siRNA或蛋白激酶C IOTA（PKCIOTA）siRNA阻断，这表明RAS和/或PKCIOTA活性需要吞咽蛋白诱导的细胞凋亡。用oncrasin -1，-60或-231治疗敏感的癌细胞导致RNA聚合酶II最大亚基的C末端结构域（CTD）的磷酸化抑制，Whish与以前的报道一致需要RNA聚合酶II的II以防止癌基因诱导的转化细胞凋亡，并且突变损害CTD功能在合成中致死，而酵母中RAS活性水平升高。用oncrasin-1治疗也导致了巨型斜肌体中PKCIOTA和剪接因子的共聚集，并破坏了PKCiota与CDK9/Cyclin T1复合物之间的相互作用，这使CTD磷酸化。因此，我们假设oncrasin化合物是具有选择性抗癌活性的新型CTD抑制剂。体内给药oncrasin-1抑制了> 70％的人肺肿瘤异种移植物的生长，并延长了含有肿瘤的裸鼠的存活，而不会引起可检测的毒性。在NCI-60细胞系上测试其中一些类似物表明，对肺，结肠，乳腺癌，卵巢和肾脏癌和oncrasin-60衍生的几个细胞系有效它的新型抗癌机制。因此，黄质蛋白化合物可能是一种新型的CTD抑制剂，它们对癌症的癌症在RAS/PKCIOTA活性增加时具有致命性。但是，在临床上对药代动力学，抗肿瘤疗效和牙齿化合物的安全性的体内评估是必要的。该提案的目的是通过评估具有或没有RAS基因突变的几种肺癌细胞系中的体外活性来确定最活跃的类似物的抗肺癌活性，其药代动力学及其体内活性和毒性。拟议的研究将提供可靠的临床前数据，以便可能对牙龈素化合物进行临床评估，并可能导致新的治疗剂的发展，这些治疗剂可用于治疗肺癌。 公共卫生相关性：我们已经确定了一组对RAS活性增加但对正常细胞的癌细胞有选择性毒性的新药物。分子表征揭示了这些化合物抑制了最大的RNA聚合酶II亚基的C末端结构域的磷酸化和功能。该提案的目的是对未来临床试验所需的对肺癌细胞和体内肺癌细胞中其抗肿瘤活性进行临床前研究。