Targeting MUC5AC mucin in breast cancer brain metastasis

摘要 在美国，乳腺癌(BC)脑/中枢神经系统(CNS)转移与低生存率有关。 女性，其中30%-40%的病例报告为三重受体阴性(TN)和表皮生长因子 受体阳性(ErbB2+)BC亚型。尽管在诊断和治疗管理方面取得了进展 BC，脑转移(BM)的病例仍有显著增加，这些BCBM之间的存活率 病人是非常惨淡的。因此，迫切需要确定BCBM的主要分子驱动因素和 用于骨髓早期检测的新型预测生物标志物S。在这方面，我们的全球转录分析 研究表明，在嗜脑(BT)细胞中，分泌凝胶形成粘蛋白MUC5AC的水平明显更高 而不是亲代BC细胞。此外，一项电子计算机分析显示，在 BCBM存档组织与原发肿瘤的比较。最重要的是，MUC5AC的增强水平 在BCBM患者和非BM BC患者的血清中检测到。这些研究强烈表明 提示MUC5AC有可能成为BCBM早期发现的潜在预测生物标志物。此外，MUC5AC 基因敲除(KD)导致BT的运动性降低、细胞黏附和血脑屏障(BBB)移位 相对于控件的单元格。重要的是，MUC5AC KD细胞显示心脏内的BM潜力降低 老鼠模型。我们对MUC5AC介导的骨髓的初步机制研究表明， Bt细胞中的CD44和cMET通路。MUC5AC与cMET的共同受体CD44v6相互作用。 以cMET的激活形式本地化，建立BCBM。CD44v6和cMET已被证明 使用透明质酸和肝细胞生长因子通过前馈循环优先增强BM 小路。我们还观察到在小胶质细胞/星形胶质细胞存在的情况下，Bt细胞中MUC5AC的强阳性表达 条件培养液。用PLB-1001靶向MUC5AC可减少Bt细胞中MUC5AC的表达。我们 假设MUC5AC通过CD44v6/cMET轴增强BCBM，因此可能是一个有用的标记 预测煤层气。在目标1中，我们将建立MUC5AC作为高危BC中BM的一个新的预测生物标志物 患者，并检查MUC5AC在原发肿瘤中的高表达是否预测骨髓，并与 治疗反应、总存活率和复发。目的2研究将确定MUC5AC介导的调节 BM通过cMET/CD44v6/NF-κB轴建立临床前小鼠模型。在目标3中，我们将使用BBB CMET单用或与顺铂或奈拉替尼联合治疗的可穿透1期试验 TN和ErbB2+脑转移瘤的治疗策略。总而言之，建议的研究将把MUC5AC确立为 用于高危BM的新的预测生物标志物，将有助于制定BCBM的预防策略， 目前还没有治愈方法。

Abstract Breast cancer (BC) brain/central nervous system (CNS) metastasis is associated with poor survival among U.S. women, with 30-40% of these cases reported as triple receptor-negative (TN) and epidermal growth factor receptor-positive (ErbB2+) BC subtypes. Despite the progress in the diagnostic and therapeutic management of BC, there is still a significant increase in brain metastasis (BM) cases, and the survival rate among these BCBM patients is very bleak. Therefore, there is an urgent need to identify primary molecular drivers of BCBM and novel predictive biomarker(s) for the early detection of BM. In this regard, our global transcriptomic analysis showed that levels of a secretory gel-forming mucin, MUC5AC, is significantly higher in the brain tropic (BT) cells than the parental BC cells. Additionally, an in silico analysis revealed significantly higher levels of MUC5AC in the archived BCBM tissues compared to the primary tumors. Most importantly, the augmented levels of MUC5AC were detected in the serum of BCBM patients compared to non-BM BC patients. These studies strongly suggest that MUC5AC could be a potential predictive biomarker for the early detection of BCBM. Furthermore, MUC5AC knockdown (KD) resulted in reduced motility, cell adhesion, and blood-brain barrier (BBB) transmigration in BT cell lines relative to controls. Importantly, MUC5AC KD cells showed diminished BM potential in an intracardiac mouse model. Our initial mechanistic studies on the MUC5AC-mediated BM showed an important role of the CD44 and cMET pathways in BT cells. MUC5AC interacted with CD44v6, a co-receptor for cMET, and co- localized with the activated form of cMET to establish BCBM. CD44v6 and cMET have been shown to preferentially enhance BM through a feed-forward loop using hyaluronic acid and hepatocyte growth factor pathways. We also observed robust expression of MUC5AC in BT cells in the presence of microglia/astrocyte conditioned media. Targeting MUC5AC with PLB-1001 reduces MUC5AC expression in BT cells. We hypothesize that “MUC5AC enhances BCBM through CD44v6/cMET-axis” and could thus be a useful marker to predict BCBM. In Aim 1, we will establish MUC5AC as a novel predictive biomarker for BM in high-risk BC patients, and examine whether high MUC5AC expression in primary tumors predicts BM, and correlates with response to therapy, overall survival, and relapse. Aim 2 studies will define the regulation of MUC5AC-mediated BM through the cMET/CD44v6/NF-κB-axis using preclinical mouse models. In Aim 3, we will use a BBB penetrable phase 1 tested cMET inhibitor alone or in combination with cisplatin or neratinib as novel therapeutic strategy for TN and ErbB2+ brain metastatic BC. Altogether, the proposed studies will establish MUC5AC as a novel predictive biomarker for high-risk BM and will help in developing preventive strategies for BCBM, which currently has no cure.