MicroRNAs in Human Ovarian Cancer

描述(申请人提供)：卵巢癌是西方世界妇科恶性肿瘤的主要死因。它的高死亡率是因为大多数患者(~75%)是在疾病的晚期被诊断为腹内播散性转移的。对这些患者来说，手术后再进行以铂为基础的化疗方案被视为标准护理。然而，尽管对一线化疗的初始有效率为65%-80%，大多数卵巢癌仍会复发。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，迫切需要确定导致化疗耐药和卵巢癌发展的新分子，从而导致新的靶向治疗。MicroRNAs(MiRNA)是一类在系统发育上保守的小RNA，在细胞的生存、增殖、分化和血管生成的调节中发挥重要作用。越来越多的研究表明，miRNAs在人类恶性肿瘤中经常被解除调控，其功能可能是“癌基因”，也可能是“肿瘤抑制基因”。此外，miRNA的表达特征与特定的临床癌症特征有很好的相关性，可以用来对正常组织和癌组织以及恶性肿瘤的亚型进行分类。我们的初步数据显示，miRNAs在人卵巢癌中频繁上调或下调，其中一些，特别是miR-214，参与了化疗耐药和转移，并具有致癌活性。根据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miRNAs在卵巢癌的发生、腹内扩散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miRNAs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在卵巢癌中过表达的机制；2)检测miR-214功能获得和失去功能对卵巢癌细胞表型和OSE细胞中miR-214致癌活性的影响；3)确定miR-214功能增强对转基因小鼠卵巢肿瘤发生的影响；4)验证miR-214靶基因的有效性，并确定miR-214致癌的机制。公共卫生相关性：人类卵巢癌中的microRNA卵巢癌是导致妇科恶性肿瘤死亡的主要原因。它的高死亡率是由于大多数患者(~75%)是在疾病的晚期被诊断出来的。尽管对一线化疗的初始有效率为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记物用于早期检测和识别与化疗耐药和卵巢癌发生有关的新分子，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称为microRNAs的小核苷酸的频繁变化。其中一些微小RNA参与了化疗耐药，并促使“正常”细胞发生恶性行为。我们还检测到人卵巢癌血浆中的microRNA。基于这些初步结果，我们将研究microRNAs是否可以作为卵巢癌的诊断/预后标记物、治疗靶点和原因因素。这些研究将对卵巢癌的诊断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.