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死亡的主要原因。其高死亡率是由于大多数患者（约75%）在疾病晚期被诊断为弥漫性腹腔内转移的结果。减积手术后，铂为基础的化疗方案被认为是这些患者的标准治疗。然而，尽管一线化疗的初始反应率为65%-80%，但大多数卵巢癌复发。对进一步化疗的获得性耐药性通常是治疗失败的原因，导致晚期卵巢癌的总体5年生存率仅为约25%。因此，迫切需要鉴定负责化疗耐药性和卵巢癌发展的新分子，从而导致新的靶向治疗。MicroRNA（miRNA）是一类在遗传学上保守的小分子RNA，在细胞存活、增殖、分化和血管生成等过程中起着重要的调控作用。大量的研究表明，miRNAs在人类恶性肿瘤中经常被失调，并作为“癌基因”或“肿瘤抑制基因”发挥功能。此外，miRNA表达特征与特定的临床癌症特征密切相关，并可用于对正常组织和癌组织以及恶性肿瘤亚型进行分类。我们的初步数据显示，在人类卵巢癌中，miRNAs频繁上调或下调，其中一些，特别是miR-214，参与化疗耐药性和转移，并具有致癌活性。基于这些初步的数据和事实，每个miRNA负调控数百个基因，我们假设，miRNA在卵巢癌的发生，腹腔内传播和化疗耐药性中发挥重要作用，并可能成为人类卵巢癌的治疗靶点。因此，本项目的目标是确定作为卵巢癌发病因素和治疗靶点的miRNAs。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在卵巢癌中过表达的机制; 2）检测miR-214功能获得和丧失对卵巢癌细胞的肿瘤表型的影响以及miR-214在OSE细胞中的致癌活性; 3）确定转基因小鼠中miR-214功能获得对卵巢肿瘤发生的后果和4）验证miR-214靶向基因并确定miR-214在肿瘤发生中的机制。卵巢癌是妇科恶性肿瘤的主要死亡原因，也是妇科恶性肿瘤的主要病因之一。它的高死亡率是由于大多数患者（约75%）在疾病的晚期被诊断出来。尽管一线化疗的初始反应率为65%-80%，但大多数卵巢癌会复发。对进一步化疗的获得性耐药性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，迫切需要开发用于早期检测的肿瘤标志物，并鉴定负责化疗耐药性和卵巢癌发展的新分子，从而导致新的靶向治疗。我们最近发现，在人类卵巢癌中，一类称为microRNA的小核苷酸经常发生改变。这些microRNA中的一些参与化学抗性并驱使“正常”细胞恶性行为。我们还在人卵巢癌血浆中检测到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.