Role of miR-105 in breast cancer metastasis

描述（由申请人提供）：微小RNA（miRNA）似乎在癌症进展和转移期间介导癌细胞与其宿主生态位之间的相互作用中发挥作用。我们的初步研究表明，miR-105，其在循环中的水平与早期乳腺癌（BC）患者的转移进展相关，是转移性BC（MBC）细胞的特征性表达和分泌。MiR-105下调紧密连接蛋白ZO-1，其表达减少与BC患者的转移相关。MiR-105有效诱导MBC细胞的迁移和增殖，并可通过MBC分泌的外泌体转移至癌症小生境中的正常上皮和内皮细胞，在那里它改变ZO-1表达和这些小生境细胞的屏障功能。在 在我们实验室建立的小鼠模型中，MBC分泌的exosomes和miRNAs可以被各种组织中的细胞内化，并且可以促进转移发展。本研究的目的是剖析miR-105在调节癌细胞转移潜能和破坏癌生态位中的上皮和内皮“屏障”方面的双重作用，并探索靶向miR-105介导的促转移功能的新的治疗策略。在目的1中，将研究miR-105对癌细胞粘附、迁移、侵袭、增殖和锚定非依赖性生长的作用，以及ZO-1在介导这些作用中的作用。将鉴定额外的miR-105调节基因，并确定它们在介导miR-105效应中的作用。在目标2中，将确定癌症分泌的、外泌体转移的miR-105对正常上皮和内皮小生境细胞的影响，重点是它们限制癌细胞侵袭和转移的“屏障”功能。miR-105介导的屏障破坏作用的大小和动力学将通过将上皮和内皮小生境细胞与分泌miR-105的MBC细胞共培养来确定。在目的3中，将使用BC的小鼠异种移植模型确定miR-105对生态位适应和BC转移的体内作用。将评估miR- 105干预的抗转移作用。这些对癌症分泌的miRNA的深入功能研究有助于肿瘤宿主环境的共同进化，将为疾病进展期间癌症和宿主之间的动态通信提供新的见解。这项研究还将为靶向癌症分泌的miRNA提供原理证明，作为一种新的方法，在早期癌症阶段阻断癌症导向的、促转移的小生境重塑，以预防转移。我们的长期目标是验证原发性BC中的miR-105途径，并建立标准方法来鉴定适合靶向miR-105的治疗的患者，以了解癌症分泌的miRNA的整体效应，并阐明癌症分泌的循环miRNA（例如，miR-105）作为血液传播标志物用于早期诊断或预测转移。

DESCRIPTION (provided by applicant): MicroRNAs (miRNAs) appear to play a role in mediating interactions between cancer cells and their hosting niche during cancer progression and metastasis. Our preliminary studies indicate that miR-105, whose levels in the circulation are associated with metastatic progression in early-stage breast cancer (BC) patients, is characteristically expressed and secreted by metastatic BC (MBC) cells. MiR-105 downregulates the tight junction protein ZO-1, for which reduced expression is associated with metastasis in BC patients. MiR-105 potently induces migration and proliferation in MBC cells, and can be transferred via MBC-secreted exosomes to normal epithelial and endothelial cells in the cancer niche, where it alters ZO-1 expression and the barrier function of these niche cells. In a mouse model established in our lab, MBC-secreted exosomes and miRNAs can be internalized by cells in various tissues, and can facilitate metastasis development. The goals of this study are to dissect the dual roles of miR-105 in regulating the metastatic potential of cancer cells and in destroying the epithelial and endothelial "barriers" in the cancer niche, and t explore novel therapeutic strategies that target miR-105-mediated pro-metastatic functions. In Aim 1, the effects of miR-105 on cancer cell adhesion, migration, invasion, proliferation and anchorage-independent growth, as well as the role of ZO-1 in mediating these effects, will be investigated. Additional miR-105-regulated genes will be identified and their role in mediating miR-105's effects will be determined. In Aim 2, the effects of cancer-secreted, exosome-transferred miR-105 on normal epithelial and endothelial niche cells will be determined, focusing on their "barrier" functions to restrict cancer cell invasion and metastasis. The magnitude and kinetics of miR-105-mediated barrier-destroying effects will be determined by co-culturing the epithelial and endothelial niche cells with MBC cells that secrete miR-105. In Aim 3, the in vivo effects of miR-105 on niche adaptation and BC metastasis will be determined using mouse xenograft models of BC. The anti-metastatic effect of miR- 105 intervention will be evaluated. These in-depth functional studies of cancer-secreted miRNAs that contribute to the co-evolution of the tumor-hosting environment will provide novel insights into the dynamic communication between cancer and host during disease progression. This study will also provide proof-of- principle for targeting cancer-secreted miRNAs as a novel approach to block the cancer-directed, pro-metastatic remodeling of the niche at early cancer stages for the prevention of metastasis. Our long-term objectives are to validate the miR-105 pathway in primary BC and establish standard approaches to identify patients suitable for therapies that target miR-105, to understand the global effects of cancer-secreted miRNAs, and to elucidate cancer-secreted, circulating miRNAs (e.g., miR-105) in BC patients as blood-borne markers for early diagnosis or prediction of metastasis.