Dysregulations of functional RNA modifications and hexavalent chromium lung carcinogenesis

功能性RNA修饰失调与六价铬肺癌发生

• 批准号: 10565860
• 负责人: Chengfeng Yang
• 金额: --
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-02-08 至 2023-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10565860
• 关键词: Affect; Biological Assay; Biological Process; Biology; CISH gene; Cancer Etiology; Carcinogens; Cells; Chemicals; Chronic; Control Groups; Country; DNA; Data; Down-Regulation; Environmental Carcinogens; Environmental Health; Enzyme-Linked Immunosorbent Assay; Exposure to; Gene Expression; Goals; Histones; Human; Impairment; Incidence; Janus kinase; Knockout Mice; Lung; Lung Neoplasms; Lysine; Malignant neoplasm of lung; Mediating; Messenger RNA; Metal Carcinogenesis; Methyltransferase; Microarray Analysis; Modification; Monoubiquitination; Mus; Nucleotides; Occupational; Oncogenic; Pathway interactions; Persons; Play; Post-Translational Protein Processing; Process; Promoter Regions; Property; Proteins; RNA; RNA Polymerase II; RNA Stability; Reader; Resistance; Review Literature; Ribose; Role; STAT protein; Small Interfering RNA; Tumor Burden; Tumor Tissue; Tumorigenicity; United States; Untranslated RNA; Up-Regulation; Western Blotting; cancer stem cell; cancer therapy; carcinogenesis; carcinogenicity; cell transformation; chromium hexavalent ion; conditional knockout; environmental carcinogenesis; insight; knock-down; lung carcinogenesis; lung tumorigenesis; mouse model; novel; overexpression; pollutant; promoter; recruit; stem cell self renewal; stem-like cell; transcriptome sequencing; tumor progression; tumorigenesis; ubiquitin isopeptidase; ubiquitin-protein ligase

PROJECT SUMMARY/ABSTRACT Hexavalent chromium [Cr(VI)] is one of the most common environmental carcinogens causing lung cancer, however, the mechanism of Cr(VI) carcinogenesis remains elusive. The N6-methyladenosine (m6A) modification is the most prevalent internal modification in eukaryotic messenger RNAs (mRNAs), which is dynamically regulated by three groups of proteins known as writers, erasers and readers. Recent advances in demonstrating the vital roles of RNA m6A modifications in regulating gene expression and a variety of biological processes represents a breakthrough in understanding RNA biology and functions. Moreover, accumulating evidence has shown that up- regulation of m6A modifications plays critical roles in cancer progression and cancer therapy resistances. However, it remains largely un-explored whether the m6A modification dysregulation plays a role in the carcinogenic process especially in environmental carcinogenesis. The goal of this study is to investigate the mechanism of Cr(VI) carcinogenesis by studying RNA m6A modification dysregulations, focusing on the role and mechanism of chronic Cr(VI) exposure-caused m6A writer methyltransferase like 3 (METTL3) up-regulation. Our preliminary studies found: (i) Chronic Cr(VI) exposure up-regulates METTL3 expression, which contributes causally to Cr(VI)-induced cell transformation, CSC-like property and tumorigenesis. (ii) METTL3 up-regulation is also similarly detected in chronic Cr(VI) exposure-caused human and mouse lung tumor tissues. (iii) The Jak2-Stat3 pathway is activated. (iv) Jak2 and SOCS3 mRNA levels are increased and decreased in Cr(VI)-transformed cells, respectively. Stably knocking down METTL3 significantly decreases Jak2 but increases SOCS3 mRNA levels. (v) Inhibition of the Jak2-Stat3 oncogenic pathway in Cr(VI)-transformed cells significantly reduces their CSC-like property. (vi) The repressive histone 2A (H2A) lysine 119 (K119) monoubiquitination (H2AK119ub1) levels and H2AK119ub1 enrichment at METTL3 promoter region are greatly reduced in Cr(VI)-transformed cells. (vii) The expression level of a H2A deubiquitinase USP28 is up-regulated in Cr(VI)-transformed cells. Knockdown of USP28 increases H2AK119ub1 levels but reduces METTL3 protein levels. Based on literature review and our novel preliminary data, our central hypothesis is: “METTL3 up-regulation increases Jak2 and SOCS3 mRNA m6A modifications to up-regulate Jak2 but down-regulate SOCS3 expressions, which activates the oncogenic Jak2-Stat3 pathway promoting Cr(VI) carcinogenesis”. Three aims are proposed: Aim 1 will determine the mechanism of how chronic Cr(VI) exposure up- regulates METTL3 expression focusing on the role of USP28-mediated down-regulation of histone 2A monoubiquitination. Aim 2 will demonstrate that METTL3 up-regulation increases Jak2 and SCOS3 mRNA m6A modifications to activate the Jak2-Stat3 pathway promoting Cr(VI)-exposure-induced CSC-like property and tumorigenesis. Aim 3 will demonstrate that METTL3 lung-specific deletion using a METTL3 conditional knockout mouse model impairs Cr(VI) lung tumorigenesis in mice.

项目摘要/摘要 六价铬[Cr(VI)]是最常见的环境致癌物质之一， 然而，铬(VI)的致癌机制仍不清楚。N6-甲基腺苷(M6A)修饰为 真核信使RNA(MRNAs)中最普遍的内部修饰，它是动态调节的 由三组蛋白质组成，分别为写入器、擦除器和阅读器。展示生命的最新进展 RNA m6A修饰在调节基因表达和各种生物学过程中的作用代表了一种 在理解RNA生物学和功能方面的突破。此外，越来越多的证据表明，UP- M6A修饰的调节在癌症进展和癌症治疗抵抗中起着关键作用。然而， M6A修饰失调是否在致癌过程中起作用，目前还很大程度上尚不清楚。 尤其是在环境致癌方面。本研究旨在探讨铬(VI)的作用机理 通过研究RNA m6A修饰失调的致癌作用，重点研究慢性粒细胞白血病的作用和机制 铬(VI)暴露引起M6A编写器甲基转移酶样3(METTL3)表达上调。我们的初步研究发现： (I)慢性铬(VI)暴露可上调METTL3的表达，从而导致铬(VI)诱导的细胞 转化、CSC样特性与肿瘤发生。(Ii)METTL3上调也同样在慢性疾病中被检测到 铬(VI)暴露所致的人和小鼠肺肿瘤组织。(3)JAK2-STAT3通路被激活。(Iv)JAK2 在铬(VI)转化细胞中，SOCS3基因的表达水平分别升高和降低。稳稳地敲门 下调METTL3可显著降低JAK2的表达水平，但增加SOCS3的mRNA水平。(V)JAK2-STAT3的抑制 铬(VI)转化细胞的致癌途径显著降低其CSC样特性。(六)压迫者 组蛋白2A(H_2A)赖氨酸119(K119)单素化(H_2AK119ub1)水平和H_2AK119ub1浓缩 在铬(VI)转化的细胞中，METTL3启动子区域显著减少。(Vii)H2A的表达水平 去泛素酶USP28在铬(VI)转化的细胞中上调。击倒USP28增加了H_2AK119 ub1 但会降低METTL3蛋白的水平。基于文献回顾和我们的小说初步数据，我们的中心 假说是：“METTL3上调会增加JAK2和SOCS3mRNA m6A的修饰，从而上调JAK2 但下调SOCS3的表达，从而激活致癌的JAK2-STAT3途径，促进铬(VI) 致癌作用“。提出了三个目标：目标1将确定慢性铬(VI)暴露如何上调的机制。 USP28介导的组蛋白2A下调对METTL3表达的调控作用 一元素化。目标2将证明METTL3上调增加JAK2和SCOS3mRNAm6A 激活JAK2-STAT3通路的修饰促进铬(VI)暴露诱导的CSC样特性和 肿瘤发生学。目标3将使用METTL3条件敲除来证明METTL3肺特异性缺失 小鼠模型对小鼠铬(VI)肺肿瘤形成的影响