Tumor suppressor vulnerability conferred by aneuploid loss of haploinsufficient metallothionein genes

单倍体金属硫蛋白基因的非整倍体缺失导致肿瘤抑制脆弱性

基本信息

批准号：
10469891
负责人：
Joe R Delaney
金额：
$ 135.9万
依托单位：
MEDICAL UNIVERSITY OF SOUTH CAROLINA
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-09-01 至 2025-08-31
项目状态：
未结题

项目摘要

Abstract Cancer will rarely be cured through pharmacologic targeting of single genes. Tumors evolve in response to selection pressure. Precision oncology often targets a single gene product, and that gene simply becomes mutated once the drug is administered. Although individual genes may mutate, tumor biology is nonetheless constrained to dysregulating specific pathways for each cancer type. We have previously created cutting-edge bioinformatic tools to better understand which constrained pathways are acting as tumor suppressors and oncogenes, due to collaborative gene dysregulation at the molecular pathway level. Aneuploidy is a major cause of molecular pathway changes in cancer and unfortunately each aneuploid event alters both predicted driver genes and unknown passenger genes. Investigation of causal aneuploid changes in a tumor remains difficult, if not impossible, to study with current cell biology and genetic tools. However, we have discovered a unique, commonly suppressed (70% of high-grade serous ovarian cancers have a monoallelic loss, correlating with average reduced expression), pathway which is amenable to well-controlled basic science experimentation: the cadmium response pathway. It is composed of 11 highly homologous metallothionein genes arrayed on a single chromosomal locus. Metallothioneins sequester the bulk of intracellular Zn2+ and environmental genotoxic Cd2+ ions. The loss of the metallothionein locus is associated with chromosome instability and occurs early in tumor formation. Our in vitro assays show controlled metallothionein suppression results in elevated DNA damage. However, the role of metallothioneins as tumor suppressors and as regulators of cancer cellular and molecular biology is largely unknown. This project will establish specific tumor suppressor phenotypes of metallothioneins in ovarian cancer and determine if this aneuploid pathway will serve as a representative example of how multi- genic vulnerabilities can better enable next-generation cancer therapies. We will (1) characterize in vivo the effects of metallothionein gene loss in spontaneous tumor formation in ovarian cancer, (2) develop controlled models of gene suppression enabling suppression of all 11 genes, including by a synthetic dead-Cas9-based transcription factor, (3) determine which cadmium-dependent and cadmium-independent metallothionein- regulated molecular pathways convey tumor suppressor functions, and (4) discover drug classes which best selectively kill low-metallothionein cells. Genetic tools created by this project will enable causal investigation of entire molecular pathways for future projects. Taken together, this innovative research program will directly test how an uncharacterized aneuploid-suppressed pathway contributes to oncogenesis and remains a pharmacologically targetable vulnerability throughout tumor development.

抽象的癌症很少能通过针对单一基因的药物治疗来治愈。肿瘤的进化是为了响应选择压力。精准肿瘤学通常针对单个基因产物，而该基因就简单地变成了一旦服用药物就会发生突变。尽管个体基因可能发生突变，但肿瘤生物学仍然存在仅限于失调每种癌症类型的特定途径。我们之前已经创造了尖端的生物信息学工具可以更好地了解哪些受限途径充当肿瘤抑制因子癌基因，由于分子途径水平上的协同基因失调。非整倍体是主要原因癌症的分子途径变化，不幸的是每个非整倍体事件都会改变预测的驱动因素基因和未知的乘客基因。如果使用当前的细胞生物学和遗传工具进行研究并非不可能。然而，我们发现了一个独特的，通常被抑制（70％的高级别浆液性卵巢癌具有单等位基因丢失，与平均减少表达），适合良好控制的基础科学实验的途径：镉反应途径。它由 11 个高度同源的金属硫蛋白基因排列在一个单一的染色体位点。金属硫蛋白可隔离大部分细胞内 Zn2+ 和环境遗传毒性 Cd2+ 离子。金属硫蛋白位点的丢失与染色体不稳定有关，并且发生在肿瘤早期形成。我们的体外测定显示受控金属硫蛋白抑制会导致 DNA 损伤增加。然而，金属硫蛋白作为肿瘤抑制因子以及癌症细胞和分子调节剂的作用生物学很大程度上是未知的。该项目将建立金属硫蛋白的特定肿瘤抑制表型在卵巢癌中，并确定这种非整倍体途径是否将作为多倍体如何发挥作用的代表性例子基因脆弱性可以更好地实现下一代癌症疗法。我们将 (1) 在体内表征金属硫蛋白基因缺失对卵巢癌自发肿瘤形成的影响，（2）发展受控基因抑制模型能够抑制所有 11 个基因，包括基于合成的死亡 Cas9 转录因子，(3) 确定镉依赖性和镉非依赖性金属硫蛋白- 受调节的分子途径传达肿瘤抑制功能，并且（4）发现最有效的药物类别选择性杀死低金属硫蛋白细胞。该项目创建的遗传工具将能够进行因果调查未来项目的完整分子途径。总而言之，这项创新研究计划将直接测试未表征的非整倍体抑制途径如何促进肿瘤发生并仍然是一个整个肿瘤发展过程中药理学靶向的脆弱性。