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Epigenetic reprogramming of melanoma cells by vitamin C treatment

维生素 C 治疗对黑色素瘤细胞进行表观遗传重编程

基本信息

批准号：
9104118
负责人：
Gaofeng Wang
金额：
$ 16.69万
依托单位：
UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-07-02 至 2017-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9104118
关键词：
Acetylation Ascorbic Acid Ascorbic Acid Deficiency Benign Biochemistry Cell Proliferation Cells DNA DNA Methylation DNA Sequence Alteration Development Diet Dioxygenases Environmental Risk Factor Enzymes Epigenetic Process Etiology Family Generations Genes Genetic Transcription Genome Genome Stability Goals Gulo Health High-Throughput Nucleotide Sequencing Housing Human In Vitro Iron Journals Knockout Mice Lead Link Malignant - descriptor Malignant Neoplasms Melanoma Cell Metastatic Melanoma Modification Mus Nevus Oxidases Paper Pathogenesis Patients Pattern Phase Phenotype Physiological Plasma Prevention Protein p53 Publishing Radial Growth Phase Research Role Science Signal Transduction Skin Cancer Staging System TP53 gene Testing Time Tumor Suppression Tumorigenicity Vertical Growth Phase Xenograft procedure alpha ketoglutarate ascorbate base cancer prevention cofactor demethylation design dietary supplements epigenomics genome-wide gulonolactone imaging system improved in vivo in vivo imaging malignant phenotype melanocyte melanoma novel research study restoration transcriptome transcriptome sequencing uptake whole genome

项目摘要

DESCRIPTION (provided by applicant): Melanoma occurs frequently with a significant contribution of environmental factors to its etiology. In addition to genetic mutations, aberrant epigenetic alterations also contribute to the malignant transformation of melanocytes. Recently, the loss of 5-hydroxymethylcytosine (5hmC) has been identified as a novel epigenetic mark for melanoma. The content of 5hmC is relatively high in healthy melanocytes but is gradually lost during the progression from benign nevi through malignant stages of primary and metastatic melanoma. 5hmC is converted from 5-methylcytosine (5mC) by TET (ten-eleven translocation) family dioxygenases. The global loss of 5hmC changes genome stability and genome-wide transcription patterns, leading to a cascade of phenotypic transformation from healthy melanocytes to malignant melanoma. Vitamin C was recently identified to induce the generation of 5hmC by acting as a cofactor for TET by our lab and confirmed by others. The uptake of vitamin C appears to be disrupted in melanoma cells. Therefore, it is plausible that vitamin C deficiency also contributes to the loss of 5hmC that is associated with the initiation and progression of melanoma. Preliminary results show that 0.1 mM vitamin C, a concentration in the range of healthy human plasma, increases the content of 5hmC in cultured melanoma cells (derived from radial growth phase (RGP), vertical growth phase (VGP) and metastatic phase) toward the level of healthy melanocytes. Based on these exciting findings, vitamin C treatment is hypothesized to help epigenetically reprogram melanoma cells toward healthy melanocytes by reestablishing normal 5hmC profiles in the genome. Two specific aims are proposed to test this hypothesis. Aim 1 is to examine whether vitamin C treatment reestablishes 5hmC profiles in the genome of melanoma cells toward healthy melanocytes. High-throughput sequencing will be used to characterize the vitamin C treatment-induced changes in 5hmC and transcription profiles of the whole genome in melanoma cells. Results of these experiments will determine whether vitamin C treatment causes 5hmC and transcriptome profiles in melanoma cells, particularly at RGP stage, toward healthy melanocytes. Aim 2 is to determine whether 5hmC reestablishment by vitamin C treatment decreases melanoma malignant phenotypes in vitro and tumorgenicity in vivo. In Vivo Imaging System (IVIS) and histological examinations will be conducted to analyze the formation of melanoma xenografts in Gulo knockout mice, which cannot synthesize vitamin C like humans, supplemented with or without vitamin C in the diet. Results of these experiments will determine whether vitamin C treatment reduces the malignancy of melanoma. Successful completion of this research will establish a potential role for vitamin C in reversing epigenomic alterations associated with melanoma, thereby prompting the development of novel epigenetic prevention and treatment for melanoma patients.

描述(由申请人提供)：黑色素瘤经常发生，环境因素对其病因有很大的贡献。除了基因突变，异常的表观遗传改变也有助于黑素细胞的恶性转化。最近，5-羟甲基胞嘧啶(5hmC)的缺失被确定为黑色素瘤的一个新的表观遗传学标志。在健康的黑素细胞中，5hmC的含量相对较高，但在从良性痣到原发和转移性黑色素瘤的恶性阶段的发展过程中，5hmC逐渐丢失。5HmC由5-甲基胞嘧啶(5mC)在Tet(十-十一易位)家族双加氧酶的作用下转化而来。5hmC的全球缺失改变了基因组的稳定性和全基因组的转录模式，导致了从健康的黑素细胞到恶性黑色素瘤的级联表型转化。维生素C作为Tet的辅助因子，最近被我们实验室证实可以诱导5HmC的产生，并得到了其他人的证实。黑色素瘤细胞对维生素C的摄取似乎受到干扰。因此，维生素C缺乏也可能导致5hmC的丢失，这与黑色素瘤的发生和发展有关。初步结果表明，0.1 mM维生素C浓度在健康人血浆范围内，可使培养的黑色素瘤细胞(来源于径向生长期(RGP)、垂直生长期(VGP)和转移期)的5HmC含量增加，接近健康黑素细胞的水平。基于这些令人兴奋的发现，维生素C治疗被假设通过在基因组中重建正常的5hmC图谱，帮助表观遗传学重新编程黑色素瘤细胞向健康的黑素细胞转变。为了检验这一假说，本文提出了两个具体目标。目的1是检查维生素C治疗是否重建黑色素瘤细胞基因组中朝向健康黑素细胞的5hmC图谱。高通量测序将用于表征维生素C治疗引起的黑色素瘤细胞5hmC和整个基因组转录图谱的变化。这些实验的结果将确定维生素C治疗是否导致黑色素瘤细胞，特别是在RGP阶段的5hmC和转录组向健康的黑素细胞转变。目的2确定维生素C处理后的5hmC重建是否能降低黑色素瘤的体外恶性表型和体内致瘤性。在活体成像系统(IVIS)和组织学检查将被用来分析黑色素瘤移植瘤在Gulo基因敲除小鼠中的形成，这些小鼠不能像人类那样合成维生素C，在饮食中添加或不添加维生素C。这些实验的结果将决定维生素C治疗是否会降低黑色素瘤的恶性程度。这项研究的成功完成将确立维生素C在逆转与黑色素瘤相关的表观基因组改变方面的潜在作用，从而推动针对黑色素瘤患者的新的表观遗传学预防和治疗的开发。