Investigating the role of CRAT as a driver of triple negative breast cancer chemoresistance

研究 CRAT 作为三阴性乳腺癌化疗耐药驱动因素的作用

基本信息

批准号：
10536077
负责人：
Katherine Ellen Pendleton
金额：
$ 4.68万
依托单位：
BAYLOR COLLEGE OF MEDICINE
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：
2022-08-03 至 2025-08-02
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10536077
关键词：
Ablation Acetates Acetyl Coenzyme A Acetylcarnitine Address Aftercare Alternative Splicing Automobile Driving BODIPY Biological Assay Biopsy Breast Breast Cancer Patient Breast Cancer cell line Buffers CRISPR/Cas technology Cancer Burden Carboplatin Carnitine Carnitine O-Acetyltransferase Cell Line Cell Survival Cells Cessation of life Chemoresistance Chemotherapy-Oncologic Procedure Citric Acid Cycle Coenzyme A Complementary DNA Cytosol Data Set Energy-Generating Resources Enzymes Exhibits Fatty Acids Feedback Genes Genetic Transcription Genus Hippocampus Glucose Immune system Immunocompetent Impairment In Vitro Knock-out Left Levocarnitine Levocarnitine Acetyl Lipids Measures Mediating Metabolic Metabolism Mitochondria Modeling NOD/SCID mouse Neoadjuvant Therapy Neoplasm Metastasis Nonmetastatic Oncologist Oxidative Phosphorylation Palmitates Pathway interactions Patient-derived xenograft models of breast cancer Patients Play Production Prognosis Protein Isoforms Proteins Proteomics Pyruvate RNA Regulation Residual Cancers Residual Tumors Residual state Resistance Role Stains Stress Suggestion Testing Therapeutic Transcript Transferase Translations Transmission Electron Microscopy Tumor Burden Western Blotting Xenograft procedure aggressive breast cancer alternative treatment cancer subtypes chemotherapy docetaxel etomoxir expression vector fatty acid metabolism fatty acid oxidation improved in vivo in vivo Model inhibitor lipid metabolism long chain fatty acid metabolomics neoplastic cell oxidation patient derived xenograft model prevent pyruvate dehydrogenase response standard of care targeted treatment transcriptomics triple-negative invasive breast carcinoma tumor tumor xenograft tumor-immune system interactions

项目摘要

Project Summary/Abstract Triple negative breast cancer (TNBC) is an aggressive breast cancer subtype in which limited targeted therapies are available. Therefore, the standard of care treatment for TNBC patients is neoadjuvant chemotherapy where ~50% of patients have residual tumor burden and poor prognosis after treatment. Recently, it has been demonstrated that mitochondrial oxidative phosphorylation (oxphos) is both upregulated and a therapeutic vulnerability in chemoresistant TNBC, however, the mechanism behind this finding is not understood. The tricarboxylic acid cycle (TCA), which produces reducing equivalents necessary for oxphos, is requires the molecule acetyl-CoA (AcCoA). AcCoA can be derived from the breakdown of long chain fatty acids during fatty acid oxidation (FAO). Because heightened fatty acid metabolism has been associated with improved survival in TNBC, it is possible that chemoresistant TNBC derives AcCoA from fatty acids, fueling the TCA and oxphos. The gene carnitine acetyl transferase (CRAT) produces an enzyme (CrAT) that catalyzes the reversible transfer of an acetyl group between CoA and carnitine within the mitochondria. It is thought that CrAT buffers the pool of free AcCoA to maximize the energetic needs of the TCA cycle and to prevent pyruvate dehydrogenase inhibition via excess AcCoA. Within chemoresistant TNBC, greater transcription and/or translation of CRAT may maximize TCA-derived reducing equivalents needed for oxphos, aiding in chemoresistance. We have identified the fatty acid metabolism pathway and CRAT as significantly enriched in chemotherapy (docetaxel combined with carboplatin, standard NACT for TNBC)-resistant versus chemo- sensitive TNBC PDXs and patient biopsies (NCT02547987) at the RNA and protein levels. In a preliminary analysis of post-versus pre-NACT TNBC patient derived xenograft (PDX) tumors, I also found increased cytosolic lipid droplets (LDs) in carboplatin treated PDXs compared to vehicle by transmission electron microscopy (TEM), suggestive of enhanced fatty acid metabolism. Therefore, I hypothesize that elevated expression of CRAT in chemoresistant TNBC provides enhanced metabolic plasticity, buffering lipid derived accumulation of AcCoA to maximize TCA cycle flux and oxphos, aiding in chemoresistance. I will address this hypothesis by determining if AcCoA is preferentially derived from increased fatty acid oxidation in chemoresistant TNBC. I will investigate if CRAT ablation impairs chemosensitivity and survival using both in vitro and in vivo models. I will also determine which isoform of CRAT is necessary and sufficient to drive chemoresistance. Together, these studies will improve our mechanistic understanding of increased oxphos in residual TNBC and provide rationale for therapies targeting CrAT function to improve prognosis for chemoresistant patients.

项目概要/摘要三阴性乳腺癌（TNBC）是一种侵袭性乳腺癌亚型，其中靶向药物有限可以采用治疗方法。因此，TNBC患者的护理治疗标准是新辅助治疗化疗中约 50% 的患者有残留肿瘤负荷，且治疗后预后不良。最近，已经证明线粒体氧化磷酸化（oxphos）均上调以及化疗耐药性 TNBC 的治疗脆弱性，然而，这一发现背后的机制尚不清楚明白了。三羧酸循环 (TCA) 产生氧化磷所需的还原当量，是需要乙酰辅酶A (AcCoA) 分子。 AcCoA 可源自长链脂肪的分解脂肪酸氧化过程中的酸（FAO）。因为脂肪酸代谢增强与提高 TNBC 的存活率，化疗耐药性 TNBC 可能从脂肪酸中衍生出 AcCoA，从而促进 TCA 和氧化磷。肉毒碱乙酰转移酶 (CRAT) 基因产生一种酶 (CrAT)，可催化线粒体内 CoA 和肉碱之间乙酰基的可逆转移。据认为 CrAT 缓冲游离 AcCoA 池，最大限度地满足 TCA 循环的能量需求并防止丙酮酸通过过量的 AcCoA 抑制脱氢酶。在化学抗性 TNBC 中，更大的转录和/或 CRAT 的翻译可以最大限度地提高 oxphos 所需的 TCA 衍生还原当量，从而有助于化学耐药性。我们已经确定脂肪酸代谢途径和 CRAT 显着富集于化疗（多西紫杉醇联合卡铂，TNBC 的标准 NACT）耐药与化疗耐药 RNA 和蛋白质水平的敏感 TNBC PDX 和患者活检 (NCT02547987)。在初步的对 NACT 后与 NACT 前 TNBC 患者来源的异种移植 (PDX) 肿瘤的分析，我还发现增加通过传输电子将卡铂处理的 PDX 中的胞质脂滴 (LD) 与载体进行比较显微镜（TEM）显示脂肪酸代谢增强。因此，我假设升高 CRAT 在耐药 TNBC 中的表达可增强代谢可塑性，缓冲脂质 AcCoA 的衍生积累可最大限度地提高 TCA 循环通量和氧化磷，从而有助于化学耐药性。我将通过确定 AcCoA 是否优先源自增加的脂肪酸来解决这一假设化学抗性 TNBC 中的氧化。我将调查 CRAT 消融是否会损害化疗敏感性和生存率使用体外和体内模型。我还将确定 CRAT 的哪种亚型是必要且充分的驱动化疗耐药性。总之，这些研究将提高我们对增加的机制的理解 oxphos 存在于残余 TNBC 中，并为针对 CrAT 功能的治疗提供理论依据，以改善预后化疗耐药患者。