Mechanism of Hexavalent Chromium Carcinogenesis Role of Long Non-Coding RNA Dysregulation

六价铬致癌机制与长非编码RNA失调的作用

• 批准号: 10823032
• 负责人: Chengfeng Yang
• 金额: $ 35.89万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10823032
• 关键词: 3' Untranslated Regions; Affect; Affinity Chromatography; Biological Assay; Cancer Etiology; Carcinogens; Cell Maintenance; Cells; Chromatin Remodeling Factor; Chronic; Country; DNA Methylation; DNA Repair Gene; Data; Down-Regulation; Environmental Carcinogens; Environmental Health; Epigenetic Process; Exposure to; Gene Expression; Genetic Transcription; Goals; Guanine Nucleotide Exchange Factors; Histones; KDM5B gene; Knockout Mice; Length; Luciferases; Lung; Lysine; MAP Kinase Gene; Malignant Neoplasms; Mediating; Metabolic; Metal Carcinogenesis; Mus; Neoplasm Metastasis; Nuclear; Occupational; Oncogenic; PARP inhibition; Persons; Phenocopy; Phenotype; Play; Poly(ADP-ribose) Polymerases; Porifera; Post-Translational Protein Processing; Property; Proteins; RNA; RNA Polymerase II; Reactive Oxygen Species; Regulator Genes; Relapse; Reporter; Review Literature; Role; Series; United States; Untranslated RNA; cancer cell; cancer initiation; cancer stem cell; carcinogenesis; carcinogenicity; cell transformation; chromium hexavalent ion; genotoxicity; insight; knock-down; lung carcinogenesis; lung tumorigenesis; novel; overexpression; pollutant; promoter; recruit; rho GTP-Binding Proteins; stem cell differentiation; stem-like cell; therapy resistant; tumorigenesis

PROJECT SUMMARY/ABSTRACT Hexavalent chromium [Cr(VI)] is a common and well-recognized environmental carcinogen causing lung and other cancers, however, the mechanism of Cr(VI) carcinogenesis remains elusive. Previous Cr(VI) carcinogenesis studies mostly focus on its genotoxic effects. However, studies showed that Cr(VI) exposure also causes non- genotoxic effects such as epigenetic changes as evidenced by dysregulations in DNA methylation and histone posttranslational modifications. While these observations open new directions for studying Cr(VI) carcinogenesis, it remains to be determined how Cr(VI)-caused epigenetic dysregulations contribute to Cr(VI) carcinogenesis. Moreover, very little is known about the role of non-coding RNAs (ncRNAs) especially the long non-coding RNAs (lncRNAs), another epigenetic mechanism regulating gene expression, in Cr(VI) carcinogenesis. Recent studies show that lncRNAs are emerging key regulators of gene expression and play critical roles in cancer. The goal of this study is to investigate the mechanism of Cr(VI) carcinogenesis focusing on the role of lncRNA dysregulation. Our preliminary studies found: (i) Chronic Cr(VI) exposure increases the expression of the lncRNA ABHD11-AS1, which contributes causally to Cr(VI)-induced cell transformation, cancer stem cell (CSC)-like property and tumorigenesis; (ii) Chronic Cr(VI) exposure down-regulates the expression of miR-182-5p; but knockdown of ABHD11-AS1 increases the level of miR-182-5p. Moreover, overexpressing miR-182-5p in Cr(VI)-transformed cells significantly reduces their transformed phenotypes, phenocopying the effect of ABHD11-AS1 knockdown; (iii) The Rho GTPase Rac1 and Erk1/2 MAPK are highly activated in Cr(VI)-transformed cells; (iv) The expression level of the oncogenic Rac-GEF Tiam1 is significantly up-regulated in Cr(VI)-transformed cells; but overexpressing miR- 182-5p or knockdown of ABHD11-AS1 greatly decrease Tiam1 level; (v) The expression level of PARP-1, a critical DNA repair gene and a key regulator of gene expression, is significantly up-regulated in Cr(VI)-transformed cells; (vi) The level of protein PARylation is drastically increased in Cr(VI)-transformed cells; inhibition of PARP-1 or knockdown of PARP-1 greatly decrease the levels of protein PARylation and ABHD11-AS1 and the transformed phenotype of Cr(VI)-transformed cells. Based on literature review and our novel preliminary data, our central hypothesis is: “Chronic Cr(VI) exposure-upregulated lncRNA ABHD11-AS1 sponges miR-182-5p and causes its down-regulation, which leads to increased level of the oncogenic Rac-GEF Tiam1 promoting Cr(VI) carcinogenesis”. Three aims are proposed: Aim 1 will determine the mechanism by which chronic Cr(VI) exposure up-regulates ABHD11-AS1. Aim 2 will demonstrate that ABHD11-AS1 sponges miR-182-5p causing its down- regulation and promoting Cr(VI)-exposure-induced CSC-like property, cell transformation and tumorigenesis. And Aim 3 will demonstrate that down-regulation of miR-182-5p increases levels of the oncogenic Rac-GEF Tiam1 promoting Cr(VI)-exposure-induced CSC-like property, cell transformation and tumorigenesis. Tiam1 knockout mice will be used to demonstrate that Tiam1 plays an important role in Cr(VI)-induced lung carcinogenesis.

项目摘要/摘要 六价铬[CR（VI）]是一种常见且公认的环境致癌物，导致肺和其他 但是，CR（VI）癌变的机理仍然难以捉摸。先前的CR（VI）癌变 研究主要集中于其遗传毒性作用。但是，研究表明，CR（VI）的暴露也会导致非 - 遗传毒性作用，例如表观遗传学变化，如DNA甲基化和组蛋白的失调所证明 翻译后修改。这些观察结果为研究CR（VI）致癌的新方向开放，但 尚待确定CR（VI）指示的表观遗传失调如何促进CR（VI）癌变。 此外，关于非编码RNA（NCRNA）的作用，尤其是长的非编码RNA的作用知之甚少 （LNCRNA）是CR（VI）癌变中调节基因表达的另一种表观遗传机制。最近的研究 表明LNCRNA是基因表达的主要调节剂，并在癌症中起关键作用。目标 这项研究是为了研究CR（VI）致癌的机理，重点是LNCRNA失调的作用。 我们的初步研究发现：（i）慢性CR（VI）暴露增加了lncrna abhd11-as1的表达 有时会导致CR（VI）诱导的细胞转化，癌症干细胞（CSC）样性质，并且 肿瘤发生； （ii）慢性CR（VI）暴露降低了miR-182-5p的表达；但是击倒 ABHD11-AS1增加了miR-182-5p的水平。此外，在CR（VI）转化的细胞中过表达miR-182-5p 显着降低了它们转化的表型，表达了ABHD11-AS1敲低的作用； （iii） Rho GTPase Rac1和ERK1/2 MAPK在CR（VI）转化的细胞中被高度激活。 （iv）表达水平 在CR（VI）转化的细胞中，致癌RAC-GEF TIAM1显着上调。但是过表达mir- 182-5p或ABHD11-AS1的敲低大大降低了TIAM1水平； （v）PARP-1的表达水平，一个关键 DNA修复基因和基因表达的关键调节剂在CR（VI）转化的细胞中显着上调。 （vi）在CR（VI）转化的细胞中，蛋白质抚养的水平急剧增加；抑制PARP-1或 PARP-1的敲低大大降低了蛋白质荷和ABHD11-AS1的水平以及转化的 CR（VI）转化细胞的表型。根据文献综述和我们的新型初步数据，我们的中央 假设是：“慢性CR（VI）暴露于lncrna abhd11-As1 sponges mir-182-5p，并导致其导致其 下调，导致促进CR（VI）的致癌RAC-GEF TIAM的水平升高 提出了三个目标：AIM 1将确定慢性CR（VI）暴露的机制 上调ABHD11-AS1。 AIM 2将证明ABHD11-AS1 sponges mir-182-5p导致其下降 - 调节和促进CR（VI）暴露诱导的CSC样性质，细胞转化和肿瘤发生。和 AIM 3将证明miR-182-5p的下调增加了致癌的RAC-GEF TIAM1 促进CR（VI）暴露诱导的CSC样性质，细胞转化和肿瘤发生。 Tiam1淘汰赛 小鼠将用于证明TIAM1在CR（VI）诱导的肺癌发生中起重要作用。