Determination of molecular pathways regulating LOT1 mediated growth suppressions

产品说明：我们先前报道了通过分析正常和恶性转化的大鼠卵巢表面上皮（ROSE）细胞（一种体外卵巢癌模型）之间的基因表达差异发现LOT 1（转化时丢失）基因（GenBank登录号U 72620）。 与正常祖细胞相比，该基因在独立转化的ROSE细胞系中经常显示出表达降低或丧失。基于这些观察结果，我们认为LOT 1基因是一个潜在的参与调控人类卵巢癌的候选基因。 为了在模型系统中将这一发现转化为人类疾病，我们克隆了人类同源物LOT 1（GenBank登录号72621）。有趣的是，人类基因定位于6号染色体第25带（6 q25），这是卵巢癌和许多其他实体瘤中杂合性缺失（洛）的位点。 LOT 1基因的表达在11个卵巢癌细胞系中的7个中丢失或降低，与大鼠卵巢癌细胞系中的发现一致。 LOT 1的氨基酸序列分析表明，它是一个含有锌指结构域的蛋白质，具有转录因子的特征结构域。 功能分析证明，它是一个核蛋白，具有潜在的转录因子的作用。 我们还发现LOT 1基因参与表皮生长因子受体（EGFR）信号通路，是卵巢癌细胞生长的负调控因子。 该提案的目的是通过确定LOT 1的下调或表达/功能丧失如何转导抗增殖信号并作为肿瘤/生长抑制基因调节抑制恶性表型的其他基因来进一步确定LOT 1的临床重要性。 为了详细阐述这些机制，我们将研究与LOT蛋白作用相关的上游调节因子和下游事件，并确定这些正常过程在卵巢恶性肿瘤中是如何受到干扰的。 希望这些努力将导致更好地了解卵巢癌的发展和/或进展，并为更有效的诊断，治疗和/或疾病管理提供基础。

DESCRIPTION: (Applicant's Description) We previously reported discovery of the LOT1 (Lost On Transformation) gene (GenBank accession #U72620) through analysis of gene expression differences between normal and malignantly transformed rat ovarian surface epithelial (ROSE) cells, an in vitro ovarian cancer model. The gene frequently shows decreased or lost expression in independently transformed ROSE cell lines compared to the normal progenitor cells. Based on these observations, we considered the LOT1 gene a potential candidate gene involved in regulating human ovarian cancer. In an effort to translate this finding in a model system to human disease, we cloned the human homologue, LOT1 (GenBank accession #72621). Interestingly, the human gene maps to chromosome 6 at band 25 (6q25), which is a site for loss of heterozygosity (LOH) in ovarian cancer and many other solid tumors. Expression of the LOT1 gene was lost or decreased in seven out of eleven ovarian cancer cell lines consistent with the findings in the rat ovarian cancer cell lines. The deduced amino acid sequence of LOT1 indicates that it is a zinc-finger motif containing protein with domains characteristic of transcription factors. Functional assays proved that it is a nuclear protein with a potential role as a transcription factor. We also found that the LOT1 gene is involved in the epidermal growth factor receptor (EGFR) signaling pathway and is a negative regulator of the ovarian cancer cell growth. The goal of this proposal is to further ascertain the clinical importance of LOT1 by determining how down-regulation or lost expression/function of LOT1 transduces anti-proliferative signals and behaves as a tumor/growth suppresser gene regulating other genes, which inhibit the malignant phenotype. To elaborate these mechanisms we will investigate the upstream regulators and downstream events associated with the action of the LOT protein and to determine how these normal processes are perturbed in ovarian malignancies. Hopefully, these endeavors will result in a better understanding of the ovarian cancer development and/or progression and provide a basis for more effective diagnosis, treatment, and/or management of the disease.