The Role of Aberrant Splicing of EVl1 in Ovarian Cancer Pathophysiology

描述(申请人提供)：利用高分辨率比较基因组杂交(CGH)阵列分析235例卵巢癌，我们已经将卵巢癌中最常见的拷贝数增加区域缩小到3q26.2的约3.2MB宽区域。实时定量聚合酶链式反应显示，EVI1(生态型病毒整合位点-1)和MDS1/EVI1基因间融合转录本是该区域扩增最高的转录本。此外，EVI1在90%的肿瘤中发生异常剪接(Del190-515)。MDS1/EVI1和EVI1改变卵巢上皮细胞的增殖、运动、衰老和信号转导。此外，MDS1/EVI1水平升高与预后良好相关，而EVI1Del190-515与预后不良相关。因此，我们的数据表明，EVI1、MDS1/EVI1及其剪接形式在肿瘤的启动和发展过程中发挥着不同的作用，这取决于细胞环境。患者的预后可能取决于EVI1剪接变异体的相对水平。最近发现EVI1与细胞存活和抑制转化生长因子(转化生长因子β，转化生长因子？)通过增加PI3K(磷脂酰肌醇-3-激酶)活性来传递信号。因此，我们将检验这一假设，即EVI1原癌基因及其异常剪接形式的相对表达通过对PI3K和转化生长因子？发信号。我们将通过以下三个目标来检验这一假设： 1)我们将确定原癌基因EVI1异常剪接形式的过度表达是否与卵巢癌的发生、发展和药物反应有关。 2)我们将确定EVI1及其剪接变异体是否通过调节PI3K和转化生长因子来介导不同的细胞效应？信号通路。 3)我们将检验EVI1剪接变异体预测患者预后的假设。

DESCRIPTION (provided by applicant): Using high resolution comparative genomic hybridization (CGH) array analysis of 235 ovarian cancers, we have narrowed the most frequent region of copy number increase in ovarian cancers to an ~3.2 MB wide region at 3q26.2. Real time PCR of genes within this region indicated that EVI1 (ecotropic viral integration site-1) and an intergenic MDS1/EVI1 fusion transcript were the most highly amplified transcripts within this region. Moreover, EVI1 is aberrantly spliced (Del190-515) in >90% of tumors. MDS1/EVI1 and EVI1 alter proliferation, motility, senescence, and signaling in ovarian epithelial cells. Further, increases in MDS1/EVI1 levels are associated with a good prognosis while EVI1Del190-515 was associated with a poor outcome. Thus, our data suggest that EVI1, MDS1/EVI1, and its splice forms play distinct roles during tumor initiation and progression depending on the cellular context. Patient outcome is likely dependent on the relative levels of the EVI1 splice variants. EVI1 has recently been implicated in cell survival and inhibition of transforming growth factor (TGF beta, TGF?) signaling by increasing PI3K (phosphatidylinositol-3-kinase) activity. Thus, we will test the hypothesis that the relative expression of the EVI1 proto-oncogene and its aberrantly spliced forms contributes to ovarian cancer initiation, progression, and drug responsiveness through differential effects on PI3K and TGF? signaling. We will test this hypothesis through the following three aims: 1) We will determine whether overexpression of aberrantly spliced forms of the proto-oncogene EVI1 contributes to ovarian cancer initiation, progression, and drug responsiveness. 2) We will determine whether EVI1 and its splice variants mediate different cellular effects through regulating the PI3K and TGF? signaling pathways. 3) We will test the hypothesis that splice variants of EVI1 predicts patient outcomes.