Chromium in carcinogenesis and angiogenesis

六价铬[Cr（VI）]长期暴露与人类肺癌相关。虽然 铬（VI）诱导的致癌机制，机制和作用的新的兴趣 Cr（VI）的致癌作用尚不清楚。在初步研究中，我们使用人类 来自Cr（VI）暴露受试者和对照受试者的外周血单核细胞（PBMC细胞）进行整体 基因组表达谱分析，发现IL-8和CXCL 5是两个上调最多的基因 与非暴露受试者相比，在暴露组中检测到。我们通过RT-qPCR验证了我们的发现 和ELISA测定。此外，我们发现miR-199 a抑制和β-catenin上调是重要的， 用于IL-8和CXCL 5诱导。miR-199 a的强制表达和IL-8或CXCL 5的敲低抑制了两者的表达。 细胞转化和血管生成。这些发现与我们从Cr（VI）- 转化细胞和体外研究。此外，我们发现β-catenin直接激活IL-8， miR-199 a在转录水平表达，而miR-199 a直接靶向缺氧诱导因子1 β。 （HIF-1 α）抑制HIF-1 α表达。我们假设miR-199 a抑制和β-catenin 上调在Cr（VI）诱导的肿瘤发生和血管生成中是重要的，通过诱导IL-10， 8和CXCL 5表达。肿瘤细胞生长和血管生成是肿瘤的重要特征， 致癌作用，从正常细胞转化为癌细胞。为了验证这个假设，我们将 目的1）确定miR-199 a抑制和β-catenin上调在 Cr（VI）诱导的细胞转化，并确定IL-8和CXCL 5升高的机制。目标2） 确定miR-199 a、β-连环蛋白、IL-8和CXCL 5在Cr（VI）转化细胞诱导的肿瘤生长中的作用。目的 3)为了确定Cr-T细胞是否通过IL-8受体诱导嵌合肿瘤血管生成， 建立模型并测定外周血中IL-8、CXCL 5、β-连环蛋白和miR-199 a的表达水平 单核细胞（PBMC）和血浆，以及与Cr（VI）内部暴露剂量的可能相关性， 职业性接触Cr（VI）的工人。我们将使用分子方法的组合， 模型，以及来自人类受试者的血液和组织样本，以确定miR-199 a，β- 连环蛋白、IL-8和CXCL 5在Cr（VI）诱导的细胞转化、肿瘤生长和血管生成中的作用。这些 这些研究不仅有助于我们了解Cr（VI）诱发癌症的潜在机制， 还确定了潜在的新生物标志物，用于早期检测电镀工人的Cr（VI）暴露 未来的工厂

Hexavalent chromium [Cr(VI)] long-term exposure is associated with human lung cancer. Although there is emerging interest in the mechanism underlying Cr(VI)-induced carcinogenesis, the mechanism and role of Cr(VI) in inducing carcinogenesis still remains to be elucidated. In preliminary studies, we used human peripheral blood mononuclear cells (PBMC cells) from Cr(VI) exposed and control subjects to perform whole genome expression array analysis, and found that IL-8 and CXCL5 are the two most up-regulated genes detected in the exposure group compared with non-exposure subjects. We validated our findings by RT-qPCR and ELISA assay. Additionally, we found that miR-199a suppression and β-catenin upregulation are important for IL-8 and CXCL5 induction. Forced expression of miR-199a and knockdown of IL-8 or CXCL5 inhibited both cell transformation and angiogenesis. These findings are consistent with our results obtained from Cr(VI)- transformed cells and from in vitro studies. Furthermore, we found that β-catenin directly activated IL-8 expression at transcriptional level, while miR-199a directly targets hypoxia-inducible factor 1 (HIF-1) for inhibiting HIF-1 expression. We hypothesize that miR-199a suppression and β-catenin upregulation are important in Cr(VI)-induced tumorigenesis and angiogenesis through induction of IL- 8 and CXCL5 expression. Tumor cell growth and angiogenesis are the important characteristics of carcinogenesis, transformation from normal cells to cancer cells. In order to test this hypothesis, we will perform three specific aims: Aim 1) To determine role of miR-199a suppression and β-catenin upregulation in Cr(VI)-induced cell transformation, and identify the mechanism of IL-8 and CXCL5 elevation. Aim 2) To determine roles of miR-199a, β-catenin, IL-8, and CXCL5 in Cr(VI) transformed cell-induced tumor growth. Aim 3) To determine whether Cr-T cells induce tumor angiogenesis through IL-8 receptors using chimeric tumor model and determine expression levels of IL-8, CXCL5, β-catenin, and miR-199a in peripheral blood mononuclear cells (PBMCs) and plasma, and the possible correlations with Cr(VI) internal exposure doses in workers with occupational Cr(VI) exposure. We will use a combination of molecular approaches, a n animal model, and blood and tissue samples from human subjects to define roles and mechanisms of miR-199a, β- catenin, IL-8, and CXCL5 in Cr(VI)-induced cell transformation, tumor growth, and angiogenesis. These studies will not only help us understand the underlying mechanisms of Cr(VI) in inducing carcinogenesis, but also identify potential new biomarkers for early detection of Cr(VI) exposure of workers in electroplating factories in the future.