Vulnerability of SCLC based on bi-allelic genetic inactivation of RB1 and TP53

基于 RB1 和 TP53 双等位基因失活的 SCLC 脆弱性

• 批准号: 9914091
• 负责人: EDWARD L SCHWARTZ
• 金额: $ 45.5万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-12 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9914091
• 关键词: Affect; Alleles; Apoptosis; Apoptotic; Binding; Biological Markers; CDKN1B gene; CRISPR/Cas technology; Cancer Patient; Cell Cycle Regulation; Cessation of life; Cisplatin; Clinical; Clinical Treatment; Clinical Trials; Combined Modality Therapy; Congresses; Data; Disease; Drug Combinations; Drug Targeting; Drug resistance; Drug usage; Etoposide; Gene Mutation; Genetic; Goals; Grant; Growth; Human; In Vitro; Knock-in Mouse; Lead; Malignant Neoplasms; Mediating; Metastatic Neoplasm to the Liver; Missense Mutation; Modeling; Molecular Target; Mus; Mutation; Neoplasm Metastasis; Non-Small-Cell Lung Carcinoma; Oncogenic; Organoids; Outcome; Patients; Pharmaceutical Preparations; Pharmacodynamics; Pharmacology; Play; Proteins; RB1 gene; Regulation; Research; Resistance; Retinoblastoma; Retinoblastoma Protein; Role; Solid Neoplasm; Specimen; Survival Rate; System; TP53 gene; Testing; The Cancer Genome Atlas; Therapeutic Agents; Therapeutic Effect; Toxic effect; Tumor Suppressor Proteins; Ubiquitination; Xenograft procedure; antitumor effect; base; cancer cell; cancer survival; chemotherapy; clinical predictors; clinically relevant; effective therapy; gain of function mutation; genome sequencing; human model; in vivo Model; inhibitor/antagonist; lung small cell carcinoma; mouse model; mutant; novel; novel therapeutics; phase III trial; pre-clinical; relapse patients; response; small molecule; targeted treatment; treatment strategy; tumor; tumorigenesis; tumorigenic; ubiquitin-protein ligase; whole genome

There is an urgent need to identify new and effective drugs for small cell lung cancer (SCLC), a tumor characterized by aggressive growth, early metastases, and a 5-year survival rate of less than 2%. While it is initially chemosensitive, with 70% response rates to first-line therapy of cisplatin plus etoposide, most patients relapse after initial therapy with drug-resistant tumors. Dozens of new drugs have been tested for activity in SCLC over the decades, including more than 40 agents that have failed in phase III trials. None of the targeted drugs used in non-small cell lung cancer or other solid tumors are effective in SCLC. An outstanding feature of SCLC is the near uniform bi-allelic genetic inactivation of RB1 and TP53. However, since genetically inactivated RB1 and TP53 cannot be reactivated nor is it clinically feasible to reintroduce them into SCLC cells, this defining genetic feature has not led to treatment strategies for SCLC. In this grant, we will test the hypothesis that inhibiting a downstream target of Rb1 can re-establish the tumor suppressor and pro-apoptotic actions that were lost when Rb1 was inactivated. In preliminary studies, we found that modulation of only one downstream target of Rb1, the E3 ubiquitin ligase SCFSkp2/Cks1 (Skp2), can dramatically block the pro-tumorigenic consequences of the loss of Rb1, and induce Rb1-Skp2 synthetic lethal apoptosis in SCLC. This is due to the role Rb1 and Skp2 play in the regulation of p27 (CDKN1B), whereby the loss of Rb1 leads to the Skp2-mediated ubiquitination and degradation of p27 and the subsequent loss of cell cycle regulation. Most critically, we have identified active, small molecule Skp2 inhibitors to specifically target this vulnerability. The specific aims are: 1) To determine the role of the Cks1-Skp2 interaction in Rb1 and p53 deletion- induced SCLC. If the role is found to be essential, we will have identified another target to inhibit Skp2-medited p27 ubiquitination. Since some human SCLCs with p53 missense mutations may have gained new oncogenic functions (GOF), in addition to the loss of classic p53 functions, we will determine if these p53 GOF mutations affects the sensitivity to Skp2 inhibition. 2) To determine effects of Skp2 inactivation using genetic and pharmacologic approaches. Four different small molecule Skp2 inhibitors, with distinct molecular targets, will be used in several novel in vitro and in vivo models. Particular focus will be on SCLC liver metastasis, and on comparisons between chemotherapy-naïve and chemo-resistant SCLC cells. 3) To determine the antitumor effects of Skp2 inhibitors in a more clinically relevant mouse tumor model using a large panel of SCLC PDXs (patient-derived xenografts). Comparisons will be made between PDXs derived from chemotherapy-naïve and chemo-resistant SCLC tumors, including “isogenic” PDXs derived from serial specimens from the same patient pre- and post-chemotherapy. When completed, research in this proposal will potentially benefit most SCLC patients since bi-allelic inactivation of RB1 and TP53 is nearly uniform in SCLC.

迫切需要寻找治疗小细胞肺癌(SCLC)的新的有效药物。 以侵袭性生长、早期转移和5年存活率不到2%为特征。虽然它是 最初对化疗敏感，对顺铂加依托泊苷一线治疗有70%的有效率，大多数患者 对耐药肿瘤进行初步治疗后复发。数十种新药已经在美国进行了活性测试 SCLC几十年来，包括40多种在III期试验中失败的药物。没有一个目标 治疗非小细胞肺癌或其他实体肿瘤的药物对小细胞肺癌有效。 小细胞肺癌的一个突出特征是RB1和TP53几乎一致的双等位基因失活。 然而，由于基因失活的RB1和TP53不能重新激活，因此在临床上也不可行 将它们重新引入小细胞肺癌细胞，这种明确的遗传特征并没有导致小细胞肺癌的治疗策略。在……里面 在这项研究中，我们将检验这样一个假设，即抑制Rb1下游靶点可以重建肿瘤 Rb1失活时失去的抑制和促凋亡作用。 在初步研究中，我们发现Rb1只有一个下游靶标，即E3泛素 连接酶SCFSkp2/Cks1(Skp2)，可以显著阻断Rb1缺失导致的促肿瘤后果，以及 诱导小细胞肺癌Rb1-Skp2合成致死性细胞凋亡。这是由于Rb1和Skp2在 调节p27(CDKN1B)，其中Rb1的缺失导致Skp2介导的泛素化和 P27的降解和随后的细胞周期调控的丧失。最关键的是，我们发现了活跃的， 小分子Skp2抑制剂专门针对这一漏洞。 具体目的是：1)确定Cks1-Skp2相互作用在Rb1和P53缺失中的作用- 诱导的小细胞肺癌。如果这个角色被发现是必不可少的，我们将确定另一个靶点来抑制Skp2-冥想 P27泛素化。由于一些带有p53错义突变的人小细胞癌可能获得了新的致癌作用 功能(GOF)，除了失去经典的P53功能外，我们还将确定这些P53 GOF突变 影响对Skp2抑制的敏感性。2)确定Skp2基因失活的效果 药理学方法。四种不同的小分子Skp2抑制剂，具有不同的分子靶点，将 可用于几种新型的体外和体内模型。特别关注的是小细胞肺癌的肝转移，以及 化疗初期和耐药小细胞肺癌细胞的比较。3)抗肿瘤活性的测定 使用大量SCLC PDX的Skp2抑制剂在更具临床相关性的小鼠肿瘤模型中的作用 (患者来源的异种移植)。将比较从化疗中提取的PDX-NAYVE和 化疗耐药的小细胞肺癌，包括从同一患者的系列标本中提取的“等基因”PDX 化疗前和化疗后。完成后，这项建议的研究将潜在地使大多数SCLC受益 患者自RB1和TP53双等位基因失活在小细胞肺癌中几乎一致。