MicroRNAs for monitoring tumor progression and predicting response to therapy

背景：MicroRNAs （miRs）在乳腺肿瘤中发生改变，影响肿瘤的发生和进展。由于miRs在循环中非常稳定，它们作为乳腺癌的非侵入性生物标志物也具有巨大的潜力。事实上，在乳腺癌患者中已经检测到循环miRs，但由于结果不一致，对其作为微创生物标志物的相关性的解释受到限制。此外，循环miR的细胞来源和调节这些潜在miR生物标志物的分子机制仍不清楚。为了解决这些问题，建立了一个高度相关的动物模型，用于体内研究潜在的miR生物标志物。携带x连锁肿瘤抑制因子Foxp3 （Foxp3sf/+）安全（sf）突变的衰老小鼠会发生自发性乳腺癌和肿瘤肺转移。对Foxp3sf/+雌性小鼠循环miRs的分析显示，在肿瘤进展和肺转移过程中，血浆miR-200c/141和miR-155水平显著升高，这些结果在一小部分乳腺癌患者中得到了验证。因此，这些miRs似乎是检测人类乳腺癌进展和预测肿瘤对治疗反应的新型生物标志物的理想候选者。假设和目标：中心假设是循环miR-200c/141和miR-155是早期检测和预测肿瘤进展和治疗反应的有用生物标志物。这一假设将在三个特定目标中得到验证：1)在大量患者群体中验证潜在的miR生物标志物，2)确定miR生物标志物在早期检测肿瘤进展和预测治疗反应中的效用，以及3)阐明循环miR生物标志物的起源和调控。方法：首先，在Foxp3sf/+小鼠模型中发现的miR生物标志物的上调将通过TaqMan miR检测在大量乳腺癌患者中得到验证。将使用最优的方法、材料、对照和匹配的个体来确保统计显著性

DESCRIPTION (provided by applicant): Background: MicroRNAs (miRs) are altered in breast tumors, influencing tumor development and progression. As miRs are remarkably stable in circulation, they also have enormous potential as non-invasive biomarkers for breast cancer. Indeed, circulating miRs have been detected in breast cancer patients, but interpretation of their relevance as minimally invasive biomarkers is limited by inconsistent results. Furthermore, the cellular source of circulating miRs and the molecular mechanisms regulating these potential miR biomarkers remain unclear. To address these issues, a highly relevant animal model for in vivo investigation of potential miR biomarkers was established. Aging mice with a Scurfy (sf) mutation of the X-linked tumor suppressor, Foxp3 (Foxp3sf/+), develop spontaneous breast cancer and tumor lung metastases. Analysis of circulating miRs in Foxp3sf/+ female mice revealed that plasma miR-200c/141 and miR-155 levels increase dramatically during tumor progression and lung metastasis, and these results were validated in a small population of breast cancer patients. Thus, these miRs appear as ideal candidates for novel biomarkers to detect the progression of human breast cancer and predict tumor response to therapies. Hypothesis and Goals: The central hypothesis is that circulating miR-200c/141 and miR-155 are useful biomarkers for early detection and prediction of tumor progression and therapeutic response. This hypothesis will be tested in three specific aims: 1) To validate potential miR biomarkers in a large patient population, 2) To determine the utility of the miR biomarkers in the early detection of tumor progression and prediction of therapeutic response, and 3) To elucidate the genesis and regulation of circulating miR biomarkers. Approach: First, the upregulation of the miR biomarkers identified in the Foxp3sf/+ mouse model will be validated in a large population of breast cancer patients using a TaqMan miR assay. The most optimal methods, materials, controls, and matched individuals will be used to ensure the statistical significance of this validation. Second, we will determine if the miR biomarkers are useful for the early detection of tumor progression, especially tumor metastasis. The utility of miR biomarkers in predicting response to treatments in breast cancer patients will be estimated by comparison with current biomarkers. Third, we will use FOXP3 Tet-off MCF7 cells to determine if miRs are released from breast cancer cells and regulated by FOXP3. The Foxp3sf/+ mouse model will be used to further investigate the cellular sources of circulating miR biomarkers. Innovation and Significance: This study will be the first to investigate 1) the utility of the miR biomarkers in predicting response o therapies, and 2) the mechanisms regulating circulating miR biomarkers during tumor progression in vivo. If confirmed, these miR biomarkers will provide non-invasive tools for improving outcomes and decreasing mortality in breast cancers with FOXP3 defects.