Analysis of AND-34 in human breast cancer

描述（由申请人提供）：人类乳腺癌对抗雌激素治疗产生耐药性的机制尚不完全清楚。在对调节这一过程的基因的无偏搜索中，Dorssers等人确定了一种新蛋白BCAR3或局灶粘附适配器蛋白p130Cas的上调是可重复的遗传事件，可诱导这种抗雌激素抗性。在并行和独立的工作中，我们克隆了小鼠and -34/BCAR3，并证明它通过Cdc25 gef样结构域与p130Cas结合。使用西方分析，我们发现AND-34在高水平表达

DESCRIPTION (provided by applicant): The mechanisms by which human breast carcinomas acquire resistance to antiestrogen therapy remain incompletely understood. In an unbiased search for genes which regulate this process, Dorssers et al determined that upregulation of either a novel protein, BCAR3, or the focal adhesion adapter protein p130Cas are reproducible genetic events that induce such antiestrogen resistance. In concurrent and independent work, we cloned murine AND-34/BCAR3 and demonstrated that it associates with p130Cas through a Cdc25 GEF-like domain. Using Western analysis, we find that AND-34 is expressed at high levels in a subset of human breast carcinomas but not normal breast tissue. We subsequently determined that overexpression of AND-34 induces PI3K, Akt and Rac activation in breast cancer cell lines. Specific Aims: 1) To determine the mechanism by which overexpression of AND-34 in human breast cancer cells induces PI3K activation, we will: A) Examine whether AND-34 associates with and positively regulates PI3K activation by transmembrane tyrosine kinase receptors in breast cancer cell lines. This work will include an analysis of signaling in AND-34 -/- tissues; B) Examine the role of p130Cas in AND-34-mediated PI3K activation; C) Examine the role of Src kinases in such PI3K activation. 2) To determine how AND-34 and related gene family members affect PI3K signaling and clinical outcome in primary human breast cancers and to examine the effect of AND-34 on ER signaling, we will: A) Contrast the ability of human NSP1, AND-34 and NSP-3 to induce Akt and Rac activation and antiestrogen resistance in human breast cancer cell lines. B) Determine by Western analysis whether NSP1, AND-34 or NSP-3 expression in primary human breast cancer specimens correlates with PI3K activation or ERa expression; C) Determine by immunohistochemistry whether NSP1, AND-34 or NSP-3 expression in primary human breast cancer specimens correlates with ERa expression, disease-free or overall survival. D) Determine if AND-34 overexpression induces ligand-independent ERa-mediated ERE transactivation.