脂肪细胞对三阴性乳腺癌细胞EMT形成及肿瘤转移的作用及机制

Metastasis has been the bottleneck problem of long-term survival for the patients who suffer from three-negative breast cancer. Tumor microenvironment is the pivotal factor of pro-metastasis. Epithelial-mesenchymal transition(EMT) which regulated by tumor microenvironment is the initial step and key driving force of metastasis. In our preliminary study, more adipocyte invasion into tumor, higher levels of leptin and LEPR were found in TNBC tissue but less in Luminal breast cancer. Also we found adipocyte HMSDC-Ad had the ability to promote migration and invasion of TNBC cell MDB-MB-435 in vitro, to induce EMT and to increase the expression of LEPR. In the present study, we plan to further explore the role of adipocyte on EMT induction, metastasis regulation, and the effect of adipocyte on LEPR expression and wnt/beta-catenin signaling pathway regulation by using MDB-MB-231,MDB-MB-435 cells, as well as TNBC surgical tissues. And also, we try to elucidate the role of leptin/LEPR/wnt/beta-catenin signaling pathways in the process of EMT induced by adipocytes. The data from the present study will provide the fundamental basis for TNBC treatment.

转移是制约三阴性乳腺癌（TNBC）患者长期生存的瓶颈问题。肿瘤微环境是肿瘤转移的关键促进因素，而受微环境调控的上皮间质转换（EMT）是控制肿瘤转移起始的关键事件。在预实验中，我们发现TNBC中脂肪细胞浸润、leptin及LEPR均显著高于Luminal 型乳腺癌，脂肪细胞可显著提升TNBC细胞体外迁移/侵袭能力、诱导EMT以及促进LEPR的表达。本项目拟HMSDC-Ad、MDB-MB-435、MDB-MB-231及TNBC临床标本为研究对象，观察脂肪细胞对TNBC细胞EMT诱导及转移促进作用，对LEPR表达以及wnt/β-catenin信号通路的调节作用，探讨leptin/LEPR/wnt/β-catenin通路在脂肪细胞诱导TNBC细胞 EMT及促转移中的作用，为基于脂肪细胞等肿瘤微环境的TNBC治疗提供理论基础。

转移是导致三阴性乳腺癌治疗失败的关键问题，靶向三阴性乳腺癌转移链条，对于进一步提高早期三阴性乳腺癌疗效具有重要意义。肿瘤微环境在肿瘤转移过程中扮演重要推手。有研究报道，脂肪细胞的浸润与前列腺癌、结肠癌、胰腺癌、卵巢癌不良预后呈正相关。乳腺癌中，研究发现脂肪浸润是乳腺癌预后不良的指标，而大样本的临床数据提示肥胖并不具有预后判断价值。本课题主要通过体内外细胞试验研究脂肪细胞在三阴性乳腺癌转移中的作用，采用real-time PCR、western blot及免疫荧光等方法评价脂肪细胞对TNBC细胞内EMT及wnt/β-catenin信号通路的影响，采用wnt/β-catenin通路的激动剂、拮抗剂及leptin的拮抗剂进行作用机制的功能确认，最后从288位临床标本中进行验证，并试图通过NGS测序进一步深入探索脂肪细胞对TNBC细胞的调控机制。结果发现：脂肪细胞促进TNBC细胞迁移、侵袭及转移；这一作用非通过EMT机制进行；Wnt/β-catenin通路及LEPR参与了对脂肪对TNBC侵袭转移能力的调节；临床标本中LEPR的表达与淋巴结分期、脉管侵犯及预后相关。本课题的结果证实了脂肪细胞是TNBC转移的重要的推动作用，证明了wnt/β-catenin通路及LEPR参与了脂肪细胞对TNBC转移的调控作用，为干预TNBC转移提供了潜在的靶点。