乳腺癌是妇女最常见的恶性肿瘤之一，影响预后的主要因素是乳腺癌复发和转移。研究表明，microRNAs在乳腺癌的恶性进程中扮演重要角色。本课题组初步发现miR-720在乳腺癌组织中呈低表达，并抑制乳腺癌细胞增殖和侵袭转移,其机制可能是miR-720靶向调控DNMT3a，从而影响增殖和侵袭转移相关分子的甲基化程度。我们将进一步采用分子生物学、细胞生物学及免疫学等实验方法明确miR-720、DNMT3a与乳腺癌细胞增殖和转移的关系。本项目拟从细胞功能、动物模型及人体乳腺癌病例三个层面探讨miR-720与DNMT3a在乳腺癌发生发展中的相互关系及其参与乳腺癌细胞增殖和侵袭转移调控的分子机制，可望获得miR-720在乳腺癌中的作用及其靶向DNMT3a参与乳腺癌细胞增殖和侵袭转移调控的可靠证据，为诠释乳腺癌发生发展的分子机制和应用microRNAs及其靶点作为诊断新指标和治疗新手段提供有力的科学依据。

Breast cancer is one of the most common malignancies in female cancer. The metastasis and recurrence adopted do the major prognostic factors of breast cancer patients. It shows that microRNAs are playing an important part in malignant process. we introduced that miR-720 was lower expressed in breast cancer tissues and inhibited the proliferation and matestasis of breast cancer cells. The molecular mechanism might be that miR-720 was target regulating DNMT3a so that influence methylation of proliferation and matestasis related factors. We will continue studying the relationship of miR-720, DNMT3a and cell proliferation and matestasis of breast cancer by using experiment methods of molecular biology, cell biology and immunology. This subject will discuss the relationship of miR-720 and DNMT3a in breast cancer and the molecular mechanisms by which they regulate cell proliferation and matestasis at the level of cellular functions，animal model and patient cases. It is expected to obtain evidence that miR-720 involved in regulating proliferation and matestasis of breast cancer cells.the results may provide powerful scientific basis for explaining the molecular mechanism in development of breast cancer and applying microRNAs and their targets as new makers for the clinical diagnosis and treatment.