Project 2: Evaluation of the Functional and Clinical Significance of the Novel Tumor Suppressor Gene BAP1

项目2：新型抑癌基因BAP1的功能和临床意义评价

• 批准号: 9753005
• 负责人: Payal Kapur
• 金额: $ 29.22万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/9753005
• 关键词: Adult; Age-Years; Alleles; Animal Model; Automobile Driving; BAP1 gene; Behavior; Biological; Biological Assay; Biological Markers; Bypass; Cancer Etiology; Cell Line; Cell model; Cells; Cessation of life; Chromosomes; Classification; Clear Cell; Clear cell renal cell carcinoma; Clinic; Clinical; Collaborations; Cyst; Databases; Deubiquitination; Development; Disease; Drosophila genus; Drug Targeting; Evaluation; Foundations; Genes; Germ-Line Mutation; Human; Human Genetics; Immunocompetent; Immunohistochemistry; In Vitro; Institution; International; Intervention; Kidney; Kidney Failure; Lead; Letters; Life Expectancy; Localized Disease; Malignant Epithelial Cell; Manuscripts; Mediating; Medical center; Metastatic Renal Cell Cancer; Microscopic; Molecular Genetics; Multivariate Analysis; Mus; Mutate; Mutation; Neoplasm Metastasis; Nephrons; Nomograms; Organism; Outcome; Patients; Perinatal mortality demographics; Pharmaceutical Preparations; Predictive Value; Preparation; Prognostic Factor; Proteins; Proteome; Proteomics; Recurrence; Renal Cell Carcinoma; Renal carcinoma; Sampling; Span 80; Specimen; Stem cells; Survival Rate; Testing; Texas; Therapeutic; Time; Tubular formation; Tumor Suppression; Tumor Suppressor Genes; Ubiquitin; Universities; VHL gene; aggressive therapy; base; carcinogenesis; cell type; clinical practice; clinically significant; cohort; comparative; congenic; drug development; experimental study; gene discovery; inhibitor/antagonist; innovation; molecular subtypes; mouse model; mutant; neoplastic; new therapeutic target; next generation; novel; outcome forecast; patient stratification; prevent; prognostic; prognostic value; reconstitution; subtype-specific therapies; targeted treatment; tumor; tumorigenesis

Project Summary Significant discoveries at UT Southwestern have set the foundation for the first molecular genetic and biological classification of sporadic renal cell carcinoma of clear -cell type (ccRCC), the most common type. Leveraging this innovation, we seek to assess the prognostic and predictive value of a mutated gene we have discovered, build the first immunocompetent animal model of ccRCC reproducing the genetics of human tumors, and identify novel targets for drug development. We discovered that the tumor suppre ssor gene BAP1 is mutated in 15% of sporadic ccRCC and that BAP1-deficient tumors tend not to have mutations in a second tumor suppressor gene PBRM1 (mutated in 50% of ccRCC). We developed and validated immunohistochemistry tests and found that whereas BAP1-deficient tumors tend to be of high grade, PBRM1- deficient tumors are typically of low grade. In patients with localized disease, BAP1 loss was associated with significantly worse prognosis (HR for RCC-specific death, 3.1; 95% CI, 2.3-4.1; p=6.77∙10-14). By leveraging samples from the International mRCC Database Consortium, a consortium that has already introduced changes in clinical practice, we seek to determine whether BAP1 loss leads to more aggressive tumors even in the metastatic setting. Based on our previous discovery that BAP1 loss is associated with mTORC1 activation, we will also test whether BAP1 is a biomarker of responsiveness to mTORC1 inhibitors clinically. Notably, both BAP1 and PBRM1 genes are located in the proximity of VHL (which is inactivated in >80% of ccRCC) in a region on chromosome 3p that is deleted in the vast majority of ccRCC. This may explain a longstanding paradox – why do humans with VHL germline mutations develop kidney cancer, but not Vhl+/- mice? We found that in mice, Bap1 and Pbrm1 are on different chromosomes than Vhl. Thus, LOH of the Vhl region in the mouse would still leave two copies of Bap1 and Pbrm1. We predicted that combined inactivation of Vhl and Bap1 (or Pbrm1) would cause ccRCC in the mouse but have been prevented from fully testing this hypothesis due to renal failure and perinatal lethality of mice with conditional loss of Bap1 in the kidney. However, conditional loss of Vhl is tolerated up to a year of age and VhlF/F;BapF/+ mice develop microscopic RCC. To bypass perinatal lethality and obtain macroscopic tumors, we will inactivate Vhl and Bap1 in the adult nephron. Finally, BAP1 is lost in tumors and consequently is not a suitable target for therapy. BAP1 is a deubiquitinase, and to develop the next generation of therapies, we will identify BAP1 substrates implicated in renal cancer. If successful, these aims will identify patients most likely to respond to mTORC1 inhibitors, help stratify patients with metastatic disease, lead to the first faithful immunocompetent animal model of ccRCC, and, following the path from gene discovery to drug development of Project 1, pave the way for the next generation of targeted therapies.

项目摘要 UT西南大学的重大发现为第一个分子遗传学奠定了基础， 透明细胞型散发性肾细胞癌（ccRCC）的生物学分类，这是最常见的类型。 利用这一创新，我们寻求评估我们所拥有的突变基因的预后和预测价值。 发现，建立第一个复制人类遗传学的ccRCC免疫活性动物模型， 肿瘤，并确定药物开发的新靶点。我们发现肿瘤抑制基因BAP 1 在15%的散发性ccRCC中发生突变，而BAP 1缺陷型肿瘤往往在第二个周期中没有突变。 肿瘤抑制基因PBRM 1（在50%的ccRCC中突变）。我们开发并验证了 免疫组织化学检测发现，BAP 1缺陷型肿瘤倾向于高级别，而PBRM 1- 缺陷型肿瘤通常是低级别的。在局限性疾病患者中，BAP 1丢失与以下因素相关： 预后显著更差（RCC特异性死亡的HR为3.1; 95% CI为2.3-4.1; p=6.77 ± 10-14）。通过利用 来自国际mRCC数据库联盟的样本，该联盟已经介绍了 随着临床实践的变化，我们试图确定BAP 1的缺失是否会导致更具侵袭性的肿瘤， 在转移性环境中。基于我们之前的发现，BAP 1缺失与mTORC 1相关， 此外，我们还将测试BAP 1是否是临床上对mTORC 1抑制剂反应性的生物标志物。 值得注意的是，BAP 1和PBRM 1基因都位于VHL附近（VHL在>80%的人中失活）。 ccRCC）在染色体3 p上的区域中缺失，该区域在绝大多数ccRCC中缺失。这可以解释A 长期存在的悖论-为什么VHL生殖系突变的人会患肾癌，而不是Vhl+/- 老鼠？我们发现，在小鼠中，Bap 1和Pbrm 1与Vhl位于不同的染色体上。因此，Vhl的洛 在小鼠中，Bap 1和Pbrm 1仍然会有两个拷贝。我们预测联合失活 Vhl和Bap 1（或Pbrm 1）的结合将在小鼠中引起ccRCC，但一直无法完全测试这一点。 由于肾功能衰竭和围产期死亡的假设与条件性损失的Bap 1在肾脏中的小鼠。 然而，Vhl的条件性丧失可耐受长达一岁，并且VhlF/F;BapF/+小鼠发展为显微镜下可见的。 RCC。为了绕过围产期致死性并获得肉眼可见的肿瘤，我们将在胎儿中检测Vhl和Bap 1。 成人肾单位最后，BAP 1在肿瘤中丢失，因此不是合适的治疗靶点。BAP 1是 为了开发下一代治疗方法，我们将鉴定涉及BAP 1的底物， 在肾癌中。如果成功，这些目标将确定最有可能对mTORC 1抑制剂产生反应的患者， 帮助对转移性疾病患者进行分层，导致第一个可靠的免疫活性动物模型， ccRCC，并遵循项目1从基因发现到药物开发的路径，为 下一代靶向治疗