Mechanisms of arsenic-induced carcinogenesis

砷致癌机制

• 批准号: 8542997
• 负责人: KESHAV K SINGH
• 金额: --
• 依托单位: BIRMINGHAM VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8542997
• 关键词: Address; Affect; Anchorage-Independent Growth; Applications Grants; Arsenic; Binding; Biological Assay; Breast; Breast Cancer Cell; Breast Epithelial Cells; Carcinogens; Catalysis; Cell Death; Cell Proliferation; Cell model; Cell physiology; Chemicals; Chromosomes; Complex; Cutaneous Fibrous Histiocytoma; Development; Dose; Endocrine Disruptors; Estradiol; Estrogens; Exposure to; Female; Functional disorder; Future; Gene Expression; Genes; Goals; Growth; Health; Hormones; Human; Induced Mutation; Interferons; Laboratories; Laboratory Animals; Ligands; Link; Long-Term Effects; Malignant Neoplasms; Mammary Gland Parenchyma; Measures; Military Personnel; Mission; Mitochondria; Mitochondrial DNA; New Agents; Oxidative Phosphorylation; Play; Population Study; Preventive; Process; Production; Reactive Oxygen Species; Reporting; Research; Resistance; Retinoids; Risk; Role; Staging; Therapeutic Agents; Veterans; Woman; Wound Healing; base; carcinogenesis; cell growth; cell transformation; complex IV; exposed human population; insight; malignant breast neoplasm; matrigel; mitochondrial DNA mutation; model development; mortality; prevent; public health relevance; respiratory; tumor; tumorigenic

DESCRIPTION (provided by applicant): Since a significant number of women serve in the military an increasing number of female veterans are impacted by breast cancer. The long-term goal of this research is to develop chemo-preventive and therapeutic agents against breast cancer to reduce the health burden in female military personnel. The current goal of this research is to identify mechanisms involved in the development of arsenic-induced breast cancer. To replicate normal field exposure conditions, we exposed breast epithelial cells to low dose of arsenic for several months. We discovered that a five month continuous exposure of breast epithelial cells to arsenic results in increased cell proliferation, increased wound healing, increased anchorage independent growth, as well as increased matrigel invasion. These studies suggest arsenic induces tumorigenic transformation of breast epithelial cells. Our preliminary studies revealed that mitochondria are important targets of arsenic induced transformation. Mitochondria control cell growth and cell death. Mitochondria perform other cellular functions including ATP production via mitochondrial oxidative phosphorylation (mtOXPHOS). We discovered that exposure to arsenic induces selective subgenomic amplification of chromosome 5p which contains many genes involved in mitochondrial function. Consistent with this finding arsenic-transformed cells show 1) increased Complex I and IV activities; 2) an increased expression of Complex I regulatory subunits NDUFA13 or GRIM19 (gene associated with retinoid interferon induced mortality) and non-regulatory NDUFB8 comprising the mtOXPHOS; and 3) increased expression of COXII subunit comprising complex IV. Furthermore our study suggest that arsenic-treatment did not 1) induce changes in Complex II and III activities and 2) alter the expression of arsenic-transporters. However, arsenic-transformed cells produce an increased level of reactive oxygen species. We hypothesize that arsenic disrupts mtOXPHOS function which contributes to tumorigenic transformation of breast epithelial cells. To address the proposed hypothesis, we plan to: Aim 1: Determine the spectrum of arsenic-induced mtOXPHOS dysfunction during progression (1, 2, 3, 4 months) to tumorigenic transformation (5 months) of mammary epithelial cells. Aim 2: Determine arsenic-induced changes affecting subunit gene expression, composition and organization of mtOXPHOS super-complexes during the progression and tumorigenic transformation of mammary epithelial cells. Aim 3: Determine a role for a regulatory and a non-regulatory subunit of mtOXPHOS Complex I in resistance to arsenic-induced cell death and tumor development. NDUFA13/GRIM19 encodes the regulatory component of mtOXPHOS Complex I and is essential for the assembly and enzymatic activity of Complex I. In contrast, NDUFB8 encodes a non- regulatory accessory subunit that is not involved in the catalysis of Complex I. The proposed studies should provide insight into the mechanism(s) involved in arsenic induced breast cancer and in the future may help prevent or treat breast cancers in female veterans.

描述（由申请人提供）： 由于大量妇女在军队服役，越来越多的女性退伍军人受到乳腺癌的影响。这项研究的长期目标是开发乳腺癌的化学预防和治疗药物，以减轻女性军人的健康负担。这项研究的当前目标是确定砷诱导乳腺癌发展的机制。为了复制正常的现场暴露条件，我们将乳腺上皮细胞暴露于低剂量的砷中数月。我们发现乳腺上皮细胞连续暴露于砷五个月导致细胞增殖增加、伤口愈合增加、锚定独立生长增加以及基质胶侵袭增加。这些研究表明砷诱导乳腺上皮细胞的致瘤性转化。我们的初步研究表明，线粒体是砷诱导转化的重要靶点。线粒体控制细胞生长和细胞死亡。线粒体执行其他细胞功能，包括通过线粒体氧化磷酸化（mtOXPHOS）产生ATP。我们发现暴露于砷会诱导染色体5 p的选择性亚基因组扩增，其中包含许多参与线粒体功能的基因。与该发现一致，砷转化的细胞显示1）增加的复合物I和IV活性; 2）增加的复合物I调节亚基NDUFA 13或GRIM 19（与类维生素A干扰素诱导的死亡相关的基因）和包含mtOXPHOS的非调节性NDUFB 8的表达;和3）增加的包含复合物IV的COXII亚基的表达。此外，我们的研究表明，砷处理没有1）诱导复合物II和III活性的变化和2）改变砷转运蛋白的表达。然而，砷转化细胞产生的活性氧水平增加。我们假设砷破坏了mtOXPHOS功能，这有助于乳腺上皮细胞的致瘤性转化。为了解决所提出的假设，我们计划：目的1：确定砷诱导的mtOXPHOS功能障碍的频谱在乳腺上皮细胞的肿瘤转化（5个月）的进展（1，2，3，4个月）。目标二：确定砷诱导的变化，影响亚基基因表达，组成和组织的mtOXPHOS超复合物在乳腺上皮细胞的进展和致瘤性转化。目标三：确定mtOXPHOS复合物I的调节和非调节亚基在抵抗砷诱导的细胞死亡和肿瘤发展中的作用。NDUFA 13/GRIM 19编码mtOXPHOS复合物I的调节组分，并且对于复合物I的组装和酶活性是必需的。相比之下，NDUFB 8编码不参与复合物I的催化的非调节辅助亚基。拟议的研究应提供深入了解砷诱导乳腺癌的机制，并在未来可能有助于预防或治疗女性退伍军人的乳腺癌。