MicroRNAs in Human Ovarian Cancer

描述（由申请人提供）：卵巢癌是西方世界妇科恶性肿瘤中导致死亡的主要原因。其高死亡率是由于大多数患者（约75%）被诊断为疾病晚期并伴有弥漫性腹腔内转移。减脂手术后的铂类化疗方案被认为是这些患者的标准治疗方案。然而，尽管一线化疗的初始有效率为65%-80%，但大多数卵巢癌复发。对进一步化疗的获得性耐药通常是治疗失败的原因，导致晚期卵巢癌的总体5年生存率仅为25%左右。因此，迫切需要发现与化疗耐药和卵巢癌发展有关的新分子，从而开发新的靶向治疗方法。MicroRNAs （miRNA）是一类在系统发育上保守的小rna，在细胞存活、增殖、分化和血管生成的调控中发挥重要作用。积累的研究表明，mirna在人类恶性肿瘤中经常被解除调控，其功能要么是“致癌基因”，要么是“抑癌基因”。此外，miRNA表达特征与特定的临床癌症特征有很好的相关性，可用于区分正常组织和癌组织以及恶性肿瘤亚型。我们的初步数据显示，mirna在人卵巢癌中频繁上调或下调，其中一些，特别是miR-214，参与化疗耐药和转移，并具有致癌活性。基于这些初步数据和每个miRNA负调控数百个基因的事实，我们假设miRNA在卵巢癌发生，腹腔内传播和化疗耐药中发挥重要作用，并可能成为人类卵巢癌的治疗靶点。因此，本项目的目的是确定mirna作为卵巢癌的致病因素和治疗靶点。为了验证我们的假设并实现我们的目标，我们将1)确定miR-214在卵巢癌中的过表达机制；2)研究miR-214的功能获得和功能丧失对卵巢癌细胞肿瘤表型的影响以及miR-214在OSE细胞中的致癌活性；3)确定miR-214功能获得对转基因小鼠卵巢肿瘤发生的影响；4)验证miR-214靶向基因，确定miR-214在肿瘤发生中的机制。卵巢癌是妇科恶性肿瘤导致死亡的主要原因。其高死亡率是由于大多数患者（约75%）被诊断为疾病晚期。尽管一线化疗的初始有效率为65%-80%，但大多数卵巢癌复发。对进一步化疗的获得性耐药通常是治疗失败的原因，导致晚期卵巢癌的总体5年生存率仅为25%左右。因此，迫切需要开发肿瘤标志物，用于早期检测和识别与化疗耐药和卵巢癌发展有关的新分子，从而导致新的靶向治疗。我们最近在人类卵巢癌中发现了一类小核苷酸（称为microRNAs）的频繁变化。其中一些microrna与化疗耐药有关，并驱使“正常”细胞产生恶性行为。我们还在人卵巢癌血浆中检测到了microRNA。基于这些初步结果，我们将研究microrna是否可以作为人类卵巢癌的诊断/预后标志物、治疗靶点和致病因素。这些研究将对卵巢癌的检测和治疗产生重大影响。

DESCRIPTION (provided by applicant): Ovarian carcinoma is the leading cause of death from gynecological malignancies in the western world. Its high death rate is a result of the fact that most patients (~75%) are diagnosed at an advanced stage of disease with disseminated intra-abdominal metastasis. Debulking surgery followed by platinum-based chemotherapy schemes is considered standard care for these patients. However, despite an initial response rate of 65%-80% to first-line chemotherapy, most ovarian carcinomas relapse. Acquired resistance to further chemotherapy is generally responsible for treatment failure, resulting in an overall 5-year survival rate of only about 25% for late- stage ovarian cancer. Thus, there is urgent need to identify novel molecules that are responsible for chemoresistance and ovarian cancer development, and thus lead to new targeted therapy. MicroRNAs (miRNA) are a class of small RNAs that are phylogenetically conserved and play important roles in the regulation of cell survival, proliferation, differentiation and angiogenesis. Accumulated studies shows that miRNAs are frequently deregulated in human malignancy and function as either "oncogenes" or "tumor suppressor genes". In addition, miRNA expression signatures correlate well with specific clinical cancer characteristics and can be used to classify normal and cancerous tissues as well as subtype of malignancy. Our preliminary data show frequent upregulation or downregulation of miRNAs in human ovarian cancer, some of which, especially miR-214, are involved in chemoresistance and metastasis and have oncogenic activity. Based on these preliminary data and the fact that each miRNA negatively regulates hundreds of genes, we hypothesize that miRNAs play significant role in ovarian carcinogenesis, intra-abdominal dissemination and chemoresistance and could be therapeutic targets for human ovarian cancer. Thus, the objective of this project is to determine the miRNAs as pathogenetic factors and therapeutic targets in ovarian cancer. To test our hypothesis and achieve our goal, we will 1) determine the mechanism of overexpression of miR-214 in ovarian cancer; 2) examine the effects of miR-214 gain- and loss-of-function on the neoplastic phenotypes of ovarian cancer cells and the oncogenic activity of miR-214 in OSE cells; 3) determine the consequence of miR-214 gain of function on ovarian tumorigenesis in transgenic mice and 4) validate the miR-214 targeted gene and determine the mechanism of miR-214 in oncogenesis. PUBLIC HEALTH RELEVANCE: MicroRNA in Human Ovarian Cancer Ovarian carcinoma is the leading cause of death from gynecological malignancies. Its high death rate is a result of the fact that most patients (~75%) are diagnosed at an advanced stage of disease. Despite an initial response rate of 65%-80% to first-line chemotherapy, most ovarian carcinomas relapse. Acquired resistance to further chemotherapy is generally responsible for treatment failure, resulting in an overall 5-year survival rate of only about 25% for late-stage ovarian cancer. Thus, there is urgent need to develop tumor markers for early detection and identify novel molecules that are responsible for chemoresistance and ovarian cancer development, and thus lead to new targeted therapy. We have recently identified frequent alterations of a class small nucleotides, called microRNAs, in human ovarian cancer. Some of these microRNAs are involved in chemoresistance and drive "normal" cells to malignant behavior. We also detected microRNA in human ovarian cancer plasma. Based on these preliminary results, we will investigate if the microRNAs could be diagnostic/prognostic markers, therapeutic targets and causal factors in human ovarian cancer. These studies will have significant impact on ovarian cancer detection and treatment.