Novel noncanonical actions of CAR in human Liver

CAR 在人类肝脏中的新的非常规作用

基本信息

批准号：
10445324
负责人：
Hongbing Wang
金额：
$ 39.08万
依托单位：
UNIVERSITY OF MARYLAND BALTIMORE
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-07-06 至 2026-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10445324
关键词：
Affect Agar Amino Acids Apoptosis Apoptotic Carcinogens Cell Line Cell Proliferation Clinical DNA biosynthesis Data Development Diagnosis Disease Down-Regulation Ectopic Expression Environment Erythropoietin Erythropoietin Receptor Event Exhibits Gene Cluster Genes Genetic Transcription Growth Growth Factor Hepatic Hepatocarcinogenesis Hepatocyte Homeostasis Human Human Activities In Vitro Incidence Knowledge Lead Liver Liver neoplasms Malignant neoplasm of liver Mediating Modeling Molecular Mus Nuclear Nude Mice Oncogenes Oncogenic Outcome Patient-Focused Outcomes Pharmacology Phenobarbital Physiological Play Primary carcinoma of the liver cells Prognosis Protein Isoforms Proteins RNA Splicing Rattus Receptor Signaling Repression Rodent Role Sampling Signal Transduction Testing Therapeutic Tissues Transgenic Mice Transgenic Organisms Tumor Promoters Tumor Suppressor Proteins Variant Xenobiotics Xenograft procedure anti-cancer base constitutive androstane receptor design drug clearance drug metabolism epidemiology study genetic approach hepatoma cell in vivo insight liver cancer model liver cell proliferation migration novel novel marker novel strategies novel therapeutics overexpression response sensor transcriptome transcriptome sequencing tumor tumor growth tumor progression tumor xenograft tumorigenesis

项目摘要

Project Summary The constitutive androstane receptor (CAR; NR1i3) is a well-established xenobiotic sensor that regulates the expression of numerous genes encoding proteins important for drug metabolism and clearance. Accumulating evidence suggests that CAR also plays noncanonical roles in coordinating diverse physiological and pathophysiological responses associated with energy homeostasis and cell proliferation. Studies in rodents have established activation of CAR as a key event promoting liver tumor formation. In contrast, CAR activation- induced replicative DNA synthesis and hepatocyte proliferation in rodents were not observed in either cultured human liver cells in vitro or in chimeric mice with humanized liver in vivo. Moreover, epidemiological studies have shown that even after long-term clinical use, phenobarbital, a prototypical CAR activator, does not increase the incidence of liver tumors in humans. Yet, the role of human CAR (hCAR) in hepatoma cell proliferation and liver cancer development remains poorly understood. The overall objective of this application is to delineate the role of hCAR in liver tumor progression and to develop a comprehensive understanding of the molecular mechanisms underlying the effects of hCAR on hepatoma cell proliferation. To this end, we have shown that 1) expression of hCAR was significantly lower in hepatocellular carcinoma (HCC) compared to normal liver and, importantly, hCAR expression is inversely correlated with HCC outcomes; 2) ectopic expression of the reference hCAR but not a splicing variant isoform (hCAR3) in hepatoma cells markedly repressed cell proliferation, soft agar colony formation, and the growth of hepatoma xenografts in nude mice; 3) RNA-seq analyses revealed that hCAR alters the expression of a cluster of tumor suppressors and oncogenes including the downregulation of erythropoietin (EPO), a pleiotropic growth factor that exhibits cell proliferation and anti-apoptosis functions; and 4) activation of human and mouse CAR differentially alters the expression of cell proliferation genes in vivo. Based on these exciting preliminary findings, we hypothesize that in stark contrast to its rodent counterparts, hCAR exhibits anticancer functions that repress the progression of HCC by downregulating EPO. This central hypothesis will be tested in two Specific Aims: Aim 1. Define the role of hCAR isoforms in hepatoma cell proliferation and HCC progression; and Aim 2. Delineate the mechanisms by which hCAR represses HCC progression. Our findings are expected to determine the role of hCAR in HCC development and provide novel mechanistic insights into hCAR-mediated suppression of HCC progression that will open the door to novel biomarkers and therapeutics.

项目概要组成型雄甾烷受体（CAR；NR1i3）是一种成熟的异生素传感器，可调节许多编码对药物代谢和清除很重要的蛋白质的基因的表达。积累中有证据表明，CAR 在协调不同的生理和功能方面也发挥着非常规的作用。与能量稳态和细胞增殖相关的病理生理反应。对啮齿动物的研究有确定 CAR 的激活是促进肝肿瘤形成的关键事件。相比之下，CAR 激活- 在两种培养物中均未观察到啮齿类动物诱导的复制性 DNA 合成和肝细胞增殖体外的人类肝细胞或体内具有人源化肝脏的嵌合小鼠。此外，流行病学研究表明研究表明，即使在长期临床使用后，苯巴比妥（一种典型的 CAR 激活剂）也不会增加人类肝脏肿瘤的发病率。然而，人 CAR (hCAR) 在肝癌细胞增殖和肝脏中的作用对癌症的发展仍知之甚少。该应用程序的总体目标是描述角色 hCAR 在肝脏肿瘤进展中的作用，并全面了解其分子机制 hCAR 对肝癌细胞增殖的影响。为此，我们证明了 1) 的表达式与正常肝脏相比，肝细胞癌 (HCC) 中的 hCAR 显着降低，重要的是， hCAR 表达与 HCC 结局呈负相关； 2) 参考 hCAR 的异位表达，但是肝癌细胞中非剪接变异异构体（hCAR3）显着抑制细胞增殖，软琼脂集落裸鼠肝癌异种移植物的形成和生长； 3) RNA-seq 分析显示 hCAR 改变一系列肿瘤抑制因子和癌基因的表达，包括促红细胞生成素的下调 (EPO)，一种多效生长因子，具有细胞增殖和抗凋亡功能； 4) 激活人和小鼠的 CAR 差异性地改变体内细胞增殖基因的表达。基于这些令人兴奋的初步发现，我们假设与啮齿类动物形成鲜明对比，hCAR 表现出通过下调 EPO 抑制 HCC 进展的抗癌功能。这个中心假设将在两个具体目标中进行测试：目标 1. 定义 hCAR 同工型在肝癌细胞增殖和 HCC 中的作用进展；目标 2. 描述 hCAR 抑制 HCC 进展的机制。我们的发现有望确定 hCAR 在 HCC 发展中的作用，并提供新的机制见解 hCAR 介导的 HCC 进展抑制将为新型生物标志物和治疗方法打开大门。