Small RNAs in Breast Cancer Metastasis

乳腺癌是最常见的癌症类型，也是西方妇女死亡的主要原因。 转移，原发性肿瘤细胞扩散到身体的远处部位形成继发性肿瘤的过程。 乳腺癌是乳腺癌患者死亡的主要原因。大多数乳腺癌（75%）表达 雌激素受体（ER），以及实验和临床证据支持ER在乳腺癌中的关键作用 转移ER α拮抗剂如他莫昔芬已用于ER α阳性乳腺癌患者（约70%）， 所有患者）用于乳腺癌预防和治疗。不幸的是，在所有ER阳性肿瘤中， 或者对这些内分泌疗法没有反应，或者在最初的成功治疗后，肿瘤复发， 内分泌抵抗性乳腺癌此外，已知三苯氧胺耐药乳腺癌变得更容易发生。 并转移到其他器官。我们最近的研究支持ER辅激活因子MED1是一种关键的 人乳腺癌他莫昔芬耐药和转移介质。重要的是，MED1 在约40 - 60%的人乳腺癌中过表达，并且MED1的过表达与 乳腺癌患者的生存率很低。有趣的是，最近的一项研究发现， 治疗后乳腺癌患者循环肿瘤细胞中的MED1突变。但 在这些过程中，MED1过表达和突变的调控和分子机制仍然存在。 定义不明确。通过生物信息学分析和实验验证，我们提供了 强有力的初步研究支持miR-205在调节MED1表达和 以及乳腺癌转移和耐药中的激活。此外，我们还发现， MED1突变在促进乳腺癌细胞转移和治疗抵抗方面异常活跃， 另一类新发现的小RNA增强子RNA的表达。在这里，我们将阐明 MED1在这些过程中的作用和分子机制， 结合体外分子生物学研究、体内原位和PDX小鼠模型、免疫- 人类患者样本染色和RNA纳米技术。我们已经建立了一个强大的基础， 具有相关专业知识的翻译研究团队，以实现以下具体目标：1）：确定角色 miR-205/ErbB3/MED1轴在人乳腺癌他莫昔芬耐药中的作用; 2）：研究miR-205/ErbB3/MED1轴在人乳腺癌他莫昔芬耐药中的作用。 MED1调节增强子RNA在乳腺癌转移中的机制; 3）：确定 靶向小RNA对乳腺癌治疗抗性和转移的影响。这项研究的完成可能会 填补了理解调节乳腺癌的新型小RNA调节回路的关键知识空白 治疗耐药性和转移，并在提供潜在的新的 他们的治疗目标。

Breast cancer is the most common type of cancer and a leading cause of death among Western women. Metastasis, a process in which primary tumor cells spread to distant sites of the body to form secondary tumors, is the primary cause of death for breast cancer patients. Most breast cancers (75%) express the estrogen receptor (ER), and both experimental and clinical evidences support key roles for ER in breast cancer metastasis. ERα antagonists such as tamoxifen have been used in ERα-positive breast cancer patients (~70% of all patients) for breast cancer prevention and treatment. Unfortunately, up to half of all ER-positive tumors either do not respond to these endocrine therapies or, after initial successful treatment, the tumors recur as endocrine-resistant breast cancer. Further, tamoxifen resistant breast cancer is known to become more aggressive and metastasize to other organs. Our recently studies supported ER coactivator MED1 as a key mediator in both tamoxifen-resistance and metastasis of human breast cancer. Importantly, MED1 overexpresses in about 40-60% of human breast cancers and the overexpression of MED1 highly correlates with poor survival of breast cancer patients. Interestingly, a recent study discovered an increased frequency of a MED1 mutation in circulating tumor cells in breast cancer patients following treatments. However, the regulation and molecular mechanisms underlying MED1 overexpression and mutation in these processes still remain poorly defined. Through both bioinformatic analyses and experimental validation, we have provided strong preliminary studies supporting that miR-205 plays an important role in regulating both MED1 expression and activation in breast cancer metastasis and resistance. Furthermore, we found that this clinically relevant MED1 mutation is hyperactive in promoting breast cancer cell metastasis and treatment resistance, as well as the expression of another class of newly identified small RNA called enhancer RNAs. Here, we will elucidate the role and molecular mechanism underlying MED1 regulation and functions in these processes using a combination of in vitro molecular biological studies, in vivo orthotopic and PDX mouse models, immuno- staining of human patient samples and RNA nanotechnology. We have assembled a strong basic and translational research team with relevant expertise to pursue the following specific aims: 1): Determine the role of the miR-205/ErbB3/ MED1 axis in tamoxifen resistance of human breast cancer; 2): Investigate the mechanisms of MED1 regulation of enhancer RNAs in breast cancer metastasis; 3): Determine the efficacy of targeting small RNAs on breast cancer therapy resistance and metastasis. Completion of this study will likely to fill a key knowledge gap in understanding novel small RNA regulatory circuits in regulating breast cancer therapy resistance and metastasis, and to make an important positive impact in providing potential novel targets for their treatment.