基底细胞样型（BasL）乳腺癌脑转移是困扰临床的难题，其机制不明确，缺少有效的早期诊断及治疗方法。本项目预实验发现，长链非编码RNA-前列腺雄激素调控转录本1（PART1）在BasL乳腺癌中特异性高表达，预示着患者更高的脑转移风险。体内实验中，上调PART1能促进癌细胞的脑转移，下调则抑制。体外实验中，PART1受雄激素受体（AR）和转录因子MAFK调控，通过吸附抑癌的miR-30a-3p/-5p和miR-433-3p，促进癌细胞的自我更新、抗失巢凋亡等能力并维持AR的激活，参与了BasL乳腺癌脑转移，但具体的机制尚待进一步探索。本课题拟利用细胞、动物及半体内模型，探讨PART1在BasL乳腺癌脑转移各阶段的具体分子机制；利用多种分子生物学技术及临床样品检测，阐明PART1异常表达的原因，及其维持AR持续性激活的分子机制。为临床BasL乳腺癌脑转移的诊治提供新的生物标记物及潜在的治疗靶点。

The brain metastasis of basal-like breast cancer is a frustrating clinical challenge. However, the specific mechanism underlying the brain metastasis of basal-like breast cancer remains not determined yet, and effective targeted therapeutic strategy is still lacking. Our preliminary research results found that expression levels of long non-coding RNA - prostate androgen-regulated transcript 1 (PART1) was specifically upregulated in basal-like breast cancer, which predicted high risk in basal-like breast cancer patients with brain metastasis. Upregulating PART1 promoted brain metastasis in basal-like breast cancer cells in vivo; conversely, silencing PART1 yielded an opposite effect on basal-like breast cancer cells. In experiments in vitro, our results further revealed that both androgen receptor (AR) and MAF BZIP Transcription Factor K (MAFK) upregulated PART1 expression, which promoted cancer cells self-renewal, anoikis resistance and constitutive activation of AR signaling through sponging tumor suppressive miR-30a-3p/-5p and miR-433-3p, resulting in brain metastasis of basal-like breast cancer. However, the specific mechanism remains further investigated. Next, we will investigate the specific functions and mechanisms in each process of brain metastasis in basal-like breast cancer by cell, animal and half-vivo model; we will further utilize versatile molecular biological techniques to clarify the molecular mechanism responsible for the cause of PART1 overexpression, and the one for constitutive activation of AR signaling; finally. Accordingly, the successful implementation of this project will provide novel auxiliary diagnostic molecule and potential therapeutic target to conquer the brain metastasis of basal-like breast cancer.