Methyl selenium regulation of Angiogenic switch Mech

描述（由申请人提供）：血管生成对于实体癌的发生和进展是必需的，并且是癌症化学预防的逻辑靶点。本授权申请将检验甲基硒醇或相关单甲基硒代谢物通过多种过程抑制血管内皮血管生成反应的假设：a）抑制导致G1细胞周期停滞的促有丝分裂信号传导; B）通过半胱天冬酶驱动的执行诱导细胞凋亡; c）抑制降解组织基质所需的基质金属蛋白酶（MMP）-2的表达。我们将1）使用生物化学、激酶药理学抑制剂和活性激酶突变体转染方法研究甲基硒抑制磷脂酰肌醇3-激酶（PI 3 K）信号级联在血管细胞G1期阻滞中的介导作用; 2）明确甲基硒诱导血管内皮细胞凋亡的途径，特别是什么半胱天冬酶被激活，线粒体和细胞色素C在它们的激活中的任何作用，以及PI 3 K和/或促有丝分裂活化蛋白激酶（MAPKJERK 1/2）抑制介导凋亡信号传导; 3）确定甲基硒靶向MMP-2表达的哪个阶段并阐明所涉及的生化/分子机制。特别是，我们将测试甲基硒醇是否破坏MMP-2和模型蛋白/肽分子中的二硫键。人脐静脉内皮细胞及其端粒化永生克隆将用于细胞培养模型中以实现这些目标。通过实现前两个目标，我们希望验证PI 3 K和/或MAPK 1/2途径对甲基硒抑制内皮细胞周期以及导致半胱天冬酶驱动执行的凋亡信号传导的介导作用。这可以为将来研究甲基硒如何与这些靶蛋白反应/相互作用以产生生物化学和细胞效应奠定基础。此外，阐明MMP-2的表达调控机制在目标3，特别是二硫键破坏作为其降解的潜在原因可能有更广泛的机制，抑制自分泌/旁分泌介导的肿瘤血管生成，生长，生存和侵袭硒的影响。

DESCRIPTION (provided by applicant): Angiogenesis is obligatory for the genesis and progression of solid cancers and is a logical target for cancer chemoprevention. This grant application will test the hypothesis that methylselenol or related monomethylselenium metabolites inhibit vascular endothelial angiogenic responses by multiple processes: a) inhibiting mitogenic signaling leading to G1 cell cycle arrest; b) inducing apoptosis through caspase-driven execution; c) inhibiting the expression of matrix metalloproteinase (MMP)-2 that is required for degrading tissue matrix. We will 1) investigate the mediator role of a methylselenium-inhibition of the phosphatidylinositol 3- kinase (PI3K) signaling cascade in vascular cell G1 arrest using biochemical, kinase pharmacologic inhibitor and active kinase mutant transfection approaches; 2) define the pathways through which methy-seLenium induces vascular endothelial cell apoptosis, especially what caspases are activated and any role of the mitochondria and cytochrome C in their activation as well as whether PI3K and/or mitogenic activated protein kinase (MAPKJERK1/2) inhibition mediate apoptosis signaling; 3) define what stage(s) of MMP-2 expression is targeted by methylselenium and elucidate the biochemical/molecular mechanisms involved. In particular, we will test whether methylselenol disrupts disulfide bonds in MMP-2 and model protein/peptide molecules. Human umbilical vein endothelial cells and their telomerized immortal clones will be used in cell culture models to accomplish these aims. By accomplishing the first 2 aims, we expect to validate a mediator role of PI3K and/or MAPK1/2 pathways for methylselenium inhibition of endothelial cell cycling as well as for apoptosis signaling leading to caspase-driven execution. This can lay the foundation for future work to investigate how methylselenium reacts/interacts with these target proteins to bring about the biochemical and cellular effects. In addition, elucidating the mechanisms of MMP-2 expression regulation in Aim 3 and especially disulfide disruption as a potential cause of its degradation may have broader mechanistic implications for inhibiting autocrine/paracrine-mediated tumor angiogenesis, growth, survival and invasiveness by selenium.