The Role of Mortalin in Thyroid Cancer

Mortalin 在甲状腺癌中的作用

• 批准号: 10583210
• 负责人: Jong-In Park
• 金额: $ 43.63万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-10 至 2028-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10583210
• 关键词: ATP Citrate (pro-S)-Lyase; Acetyl Coenzyme A; Address; Bioenergetics; Biology; Cell Death Induction; Cell Line; Cell Proliferation; Cell Survival; Cessation of life; Characteristics; Citrates; Citric Acid Cycle; Collaborations; Common Neoplasm; DNA; Data; Data Set; Development; ERR1 protein; Enzymes; GRP75; Genetic Transcription; Genus Hippocampus; Glucose; Glycolysis; Glycolysis Inhibition; Goals; Heat-Shock Proteins 70; In Vitro; Isotopes; Maintenance; Malignant Neoplasms; Malignant neoplasm of thyroid; Mediating; Metabolic; Metabolic stress; Metabolism; Mitochondria; Molecular; Molecular Chaperones; NCOR1 gene; Oncogene Activation; Oncogenes; Oncogenic; Orphan; Oxidative Stress; Patients; Process; Production; Proliferating; Pyruvate; Pyruvate Kinase; Reactive Oxygen Species; Regulation; Research; Risk; Role; Signal Transduction; Stress; Testing; The Cancer Genome Atlas; Therapeutic; Translating; Tumor Cell Line; Tumor Subtype; Up-Regulation; Warburg Effect; cancer subtypes; cell transformation; clinical efficacy; efficacy evaluation; in vivo; inhibitor; knock-down; metabolome; mortalin; neoplastic cell; novel strategies; overexpression; patient derived xenograft model; promoter; stress tolerance; synergism; therapeutic target; thyroid neoplasm; transcription factor; transcriptome sequencing; tumor; tumor metabolism

The goal of this project is to elucidate the mechanism by which mortalin is upregulated in thyroid cancer, determine the role of mortalin for tumor cell metabolism, and evaluate the potential of the metabolic processes that mortalin regulates as a therapeutic target. Metabolic reprogramming in the processes of energy and building block production is critical for tumor development and maintenance, but is associated with the risk of a lethal metabolic stress. It is therefore conceivable that malignant tumor cells might have successfully developed a protective mechanism in this context. If identified, such a mechanism may be targeted to unleash a death signal in tumor cells. We previously demonstrated that depletion of mortalin (GRP75/HSPA9), a molecular chaperone in the HSP70 family, causes lethal bioenergetic and oxidative stress in tumor cells, proposing that mortalin upregulation is a mechanism to protect tumor cells from a metabolic stress. Current understanding of the role of mortalin and its regulation is very limited in thyroid cancer, which is a metabolically active tumor. Our analysis of the TCGA RNAseq dataset revealed that a thyroid cancer-specific correlation exists between mortalin and ESRRA, an orphan transcription factor that regulates metabolic reprogramming. In our preliminary study, ESRRA depletion downregulated mortalin expression and induced cell death in different thyroid tumor cell lines, while this lethality was substantially abrogated by mortalin overexpression. These data led us to hypothesize that ESRRA is a tumor type- specific transcription factor that mediates mortalin overexpression in thyroid cancer and that mortalin is necessary for ESRRA to regulate thyroid tumor cell metabolism. Our metabolome analysis suggests that mortalin knockdown markedly depletes acetyl-CoA and its precursors in the context of the reductive TCA cycle, while increasing lactate and glucose. Moreover, depletion of ATP-citrate lyase (ACL), the enzyme that synthesizes cytosolic acetyl-CoA from citrate produced through the reductive TCA cycle, induced similar lethal effects as mortalin depletion whereas overexpression of pyruvate kinase M2 (PKM2), the enzyme that produces pyruvate to often facilitate the Warburg effect, conferred tolerance to mortalin depletion. Based upon these data, we further hypothesize that mortalin regulates the interplay between the Warburg effect and the reductive TCA cycle to facilitate cytosolic acetyl-CoA production. By extension, we predict that ACL inhibition is a promising strategy to suppress mortalin-dependent thyroid tumor cells and can be effectively combined with glycolysis inhibition. To test these hypotheses, Aim 1 will determine how ESRRA regulates mortalin transcription and examine their correlated expression and functional relationship in different thyroid tumor subtypes. Aim 2 will determine how mortalin regulates the interplay between glycolysis and the reductive TCA cycle to facilitate cytosolic acetyl-CoA production. Aim 3 will determine whether ACL is an effective target to suppress mortalin-dependent thyroid tumor cells in vitro and in vivo.

该项目的目标是阐明甲状腺癌中mortalin上调的机制， 确定mortalin对肿瘤细胞代谢的作用，并评估代谢的潜力。 作为治疗靶点调节的过程。代谢过程中的重编程 能量和构建块的产生对于肿瘤的发展和维持至关重要，但与肿瘤的发生和发展有关。 会有致命的代谢压力因此，可以想象，恶性肿瘤细胞可能具有 在这方面成功地建立了一个保护机制。如果确定这种机制， 靶向释放肿瘤细胞的死亡信号。我们以前证明了死亡素的消耗 （GRP 75/HSPA 9）是HSP 70家族中的分子伴侣，可导致致命的生物能量和氧化损伤。 肿瘤细胞中的应激，提出死亡蛋白上调是保护肿瘤细胞免受 代谢应激目前对mortalin的作用及其调节的了解非常有限， 癌症是一种代谢活跃的肿瘤。我们对TCGA RNAseq数据集的分析显示， 在死亡蛋白和ESRRA之间存在甲状腺癌特异性相关性，ESRRA是一种孤儿转录因子， 调节代谢重编程在我们的初步研究中，ESRRA缺失下调了死亡素 在不同的甲状腺肿瘤细胞系中表达并诱导细胞死亡，而这种致死率基本上是 被死亡蛋白过度表达所消除。这些数据使我们假设ESRRA是一种肿瘤类型- 在甲状腺癌中介导mortalin过表达特异性转录因子， ESRRA调节甲状腺肿瘤细胞代谢所必需的。我们的代谢组分析表明， 在还原性TCA的情况下，死亡蛋白敲低显著地消耗乙酰辅酶A及其前体 循环，同时增加乳酸和葡萄糖。此外，ATP-柠檬酸裂合酶（ACL）的耗尽，这种酶 由还原性三羧酸循环产生的柠檬酸盐合成胞浆乙酰辅酶A，诱导 与死亡蛋白耗竭类似的致死作用，而丙酮酸激酶M2（PKM 2）的过表达， 一种产生丙酮酸的酶，通常促进瓦尔堡效应，赋予对死亡蛋白的耐受性 耗尽基于这些数据，我们进一步假设，mortalin调节了 瓦尔堡效应和还原性TCA循环促进细胞溶质乙酰辅酶A的产生。进而也包括我们 预测ACL抑制是一种很有前途的策略，可以抑制依赖于死亡蛋白的甲状腺肿瘤细胞， 可有效地与糖酵解抑制剂结合。为了检验这些假设，目标1将确定如何 ESRRA调控mortalin的转录并检测其相关表达和功能关系 不同的甲状腺肿瘤亚型。目标2将确定死亡蛋白如何调节 糖酵解和还原性TCA循环以促进胞质乙酰辅酶A的产生。目标3将决定 ACL是否是一个有效的靶点，以抑制死亡蛋白依赖性甲状腺肿瘤细胞在体外和体内。