Reactive Oxygen Species-Induced CXCL8 in Ovarian Cancer

描述(申请人提供)：最近的研究表明，ROS水平升高在高级别浆液性卵巢癌(HGSOC)的生物学中起着重要作用，但ROS参与的确切机制尚未阐明。我们的初步结果表明，较高水平的ROS诱导卵巢癌细胞株和原代人类肿瘤组织中CXCL8的表达和GSK-3b的失活。HGSOC组织中CXCL8的表达增加以及同源受体CXCR1/2水平的升高与不良的临床病程有关。我们假设ROS调节CXCL8的表达以介导肿瘤生长和血管生成，其中CXCL8作为促进血管生成的旁分泌因子发挥重要作用，并可能作为促进增殖的自分泌生长因子。为了验证这一假设，我们建议实现以下三个目标。在目标1中，我们将使用小鼠原位异种移植模型来确定ROS通过GSK-3b的磷酸化诱导肿瘤细胞中CXCL8表达，从而使其对肿瘤生长的负调控失活的作用和机制。调节肿瘤细胞中ROS、CXCL8和活性GSK-3b的表达水平，可通过表达过氧化氢酶、CXCL8基因敲除或过表达，以及结构性活性或显性阴性GSK-3b的表达来实现。在目标2中，我们将使用人源化的嵌合肿瘤模型来确定CXCL8在ROS诱导的肿瘤生长和血管生成中的旁分泌和自分泌作用。在该模型中，人内皮细胞(EC)和人癌细胞通过体内多孔性PLGA海绵共植入。我们将研究在EC和肿瘤细胞中CXCR1和CXCR2基因的敲除(单独或同时)对肿瘤生长和血管生成的影响。在目标3中，我们将在一组原代人类肿瘤组织中确定ROS、CXCL8和GSK-3b的磷酸化/失活或/和活性的水平及其与HGSOC患者肿瘤分期和生存期的相关性(带临床注释)。本研究将为揭示CXCL8调控卵巢肿瘤生物学的新分子机制提供重要启示，并可能揭示ROS/GSK-3b/CXCL8信号通路作为HGSOC治疗新靶点的可能性。

DESCRIPTION (provided by applicant): Recent studies have shown that increased levels of reactive oxygen species (ROS) play an important role in the biology of high grade serous ovarian carcinoma (HGSOC), but the precise mechanisms for the involvement of ROS have not yet been elucidated. Our preliminary findings revealed that higher levels of ROS induced expression of CXCL8 and inactivation of GSK-3b in ovarian cancer cell lines and primary human tumor tissues. Increased expression of CXCL8, as well as elevated levels of the cognate receptors, CXCR1/2, in HGSOC tissues have been associated with an unfavorable clinical course. We hypothesize that ROS regulate CXCL8 expression to mediate tumor growth and angiogenesis in which CXCL8 plays a significant role as a paracrine factor for promoting angiogenesis, and, potentially as an autocrine growth factor for increasing proliferation. To test this hypothesis, we propose to perform the following three aims. In Aim 1, we will use a mouse orthotopic xenograft model to determine the role and mechanism by which ROS induce CXCL8 expression in tumor cells via phosphorylation of GSK-3b, resulting in inactivation of its negative regulation of tumor growth. Modulation of expression levels of ROS, CXCL8 and active GSK- 3b in tumor cells will obtained by expression of catalase, CXCL8 knockdown or over-expression, and expression of constitutively active or dominant negative GSK-3b. In Aim 2, we will determine the paracrine and autocrine effects of CXCL8 in ROS-induced tumor growth and angiogenesis using a humanized chimeric tumor model in which human endothelial cells (EC) and human cancer cells are co-implanted via porous PLGA sponges in vivo. The effect on tumor growth and angiogenesis of the knockdown of CXCR1 and CXCR2 in EC and tumor cells (separately or simultaneously) will be investigated. In Aim 3, we will determine levels and correlations of ROS, CXCL8, and GSK-3b phosphorylation/inactivation or/and activities with tumor stages and survival in patients with HGSOC in a panel of primary human tumor tissues (with clinical annotation). This study will provide important insights into a new molecular mechanism for the regulation of ovarian tumor biology via CXCL8, and may reveal the future potential for the ROS/GSK-3b/CXCL8 signaling pathway to serve as novel therapeutic target for HGSOC.