Department of Pathology, Albert Einstein College of Medicine / Montefiore Medical Center, 1301 Morris Park Avenue, Bronx, NY, 10461, USA.
Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine / Montefiore Medical Center, 1301 Morris Park Avenue, Bronx, NY, 10461, USA.
Breast Cancer Res. 2023 Apr 6;25(1):37. doi: 10.1186/s13058-023-01628-1.
Metastasis is a multistep process that leads to the formation of clinically detectable tumor foci at distant organs and frequently to patient demise. Only a subpopulation of breast cancer cells within the primary tumor can disseminate systemically and cause metastasis. To disseminate, cancer cells must express MenaINV, an isoform of the actin regulatory protein Mena, encoded by the ENAH gene, that endows tumor cells with transendothelial migration activity, allowing them to enter and exit the blood circulation. We have previously demonstrated that MenaINV mRNA and protein expression is induced in cancer cells by macrophage contact. In this study, we discovered the precise mechanism by which macrophages induce MenaINV expression in tumor cells. We examined the promoter of the human and mouse ENAH gene and discovered a conserved NF-κB transcription factor binding site. Using live imaging of an NF-κB activity reporter and staining of fixed tissues from mouse and human breast cancer, we further determined that for maximal induction of MenaINV in cancer cells, NF-κB needs to cooperate with the Notch1 signaling pathway. Mechanistically, Notch1 signaling does not directly increase MenaINV expression, but it enhances and sustains NF-κB signaling through retention of p65, an NF-κB transcription factor, in the nucleus of tumor cells, leading to increased MenaINV expression. In mice, these signals are augmented following chemotherapy treatment and abrogated upon macrophage depletion. Targeting Notch1 signaling in vivo decreased NF-κB signaling activation and MenaINV expression in the primary tumor and decreased metastasis. Altogether, these data uncover mechanistic targets for blocking MenaINV induction that should be explored clinically to decrease cancer cell dissemination and improve survival of patients with metastatic disease.
转移是一个多步骤的过程，导致在远处器官形成临床上可检测到的肿瘤病灶，并经常导致患者死亡。只有原发性肿瘤内的一小部分乳腺癌细胞能够系统地扩散并导致转移。为了扩散，癌细胞必须表达 MenaINV，一种肌动蛋白调节蛋白 Mena 的异构体，由 ENAH 基因编码，赋予肿瘤细胞穿越内皮细胞迁移的活性，使它们能够进入和离开血液循环。我们之前已经证明，巨噬细胞接触可以诱导癌细胞中 MenaINV mRNA 和蛋白的表达。在这项研究中，我们发现了巨噬细胞诱导肿瘤细胞中 MenaINV 表达的确切机制。我们检查了人类和小鼠 ENAH 基因的启动子，发现了一个保守的 NF-κB 转录因子结合位点。通过活细胞成像 NF-κB 活性报告基因和固定组织染色，来自小鼠和人类乳腺癌，我们进一步确定，为了最大限度地诱导癌细胞中 MenaINV 的表达，NF-κB 需要与 Notch1 信号通路合作。从机制上讲，Notch1 信号不会直接增加 MenaINV 的表达，但它通过保留肿瘤细胞核中的 p65（一种 NF-κB 转录因子）来增强和维持 NF-κB 信号，从而增加 MenaINV 的表达。在小鼠中，这些信号在化疗治疗后增强，并在巨噬细胞耗竭后被阻断。体内靶向 Notch1 信号降低了原发性肿瘤中 NF-κB 信号的激活和 MenaINV 的表达，并降低了转移。总的来说，这些数据揭示了阻止 MenaINV 诱导的机制靶点，这些靶点应该在临床上进行探索，以减少癌细胞的扩散，提高转移性疾病患者的生存率。
