Department of Urology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China.
Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China.
Int J Oncol. 2017 Jul;51(1):75-90. doi: 10.3892/ijo.2017.4003. Epub 2017 May 17.
Lymph node metastasis in patients with urinary bladder cancer (UBC) is always associated with poor prognosis and is the determinant for tumor staging and the development of treatment regimens; however, its underlying mechanisms remain to be studied. Immunohistochemical staining of tumor sections from 62 UBC patients was performed using CCR7, D2-40 and CD34 antibodies. We showed that increased CCR7 expression was significantly associated with positive lymph node status (P=0.008), pT3-T4 tumor stage (P=0.015), tumor grade (P=0.010) and worse overall survival (OS, P<0.001) and that both CCR7 expression and lymph node metastasis were independent prognostic factors for OS (P=0.031 and P=0.001, respectively) based on multivariate analysis. We found that there was a significant association between MLVD and lymph node status (P=0.006), but this relation was not observed for MVD. Furthermore, we showed that increased CCR7 expression correlated significantly with higher MLVD (P=0.014) and MVD (P=0.002). Wound-healing and matrigel transwell assays indicated that activation of CCR7 with CCL21 significantly enhanced the invasion and migration abilities of UM-UC-3 cells, and this enhanced effect was significantly abrogated by CCR7 knockdown using siRNA. Western blot analysis revealed that the phospho-ERK1/2 level was markedly increased when UM-UC-3 cells were treated with CCL21 and significantly decreased when the CCR7 gene was silenced. MEK/ERK1/2 inhibition with PD98059 significantly suppressed the migration and invasion abilities of UM-UC-3 cells and also significantly abrogated the effects of CCL21/CCR7 on cell migration and invasion. Based on these results, we conclude that activation of the CCL21/CCR7 chemoaxis promotes lymph node metastasis of UBC in at least two ways. Firstly, although CCR7 is a promoting factor that induces both lymphangiogenesis and angiogenesis, it may promote lymph node metastasis through its lymphangiogenic effect rather than through its angiogenic effect. Secondly, the CCL21/CCR7 chemoaxis promotes the migration and invasion of UBC cells via the MEK/ERK1/2 signaling pathway rather than the PI3K/AKT pathway.
膀胱癌（UBC）患者的淋巴结转移总是与不良预后相关，是肿瘤分期和治疗方案制定的决定因素；然而，其潜在机制仍有待研究。对 62 名 UBC 患者的肿瘤切片进行了 CCR7、D2-40 和 CD34 抗体的免疫组织化学染色。我们发现，CCR7 表达增加与阳性淋巴结状态（P=0.008）、pT3-T4 肿瘤分期（P=0.015）、肿瘤分级（P=0.010）和较差的总生存期（OS，P<0.001）显著相关，并且 CCR7 表达和淋巴结转移都是 OS 的独立预后因素（P=0.031 和 P=0.001）。我们发现，MLVD 与淋巴结状态之间存在显著关联（P=0.006），但与 MVD 之间没有观察到这种关系。此外，我们发现 CCR7 表达的增加与更高的 MLVD （P=0.014）和 MVD （P=0.002）显著相关。伤口愈合和基质胶 Transwell 分析表明，CCL21 激活 CCR7 显著增强了 UM-UC-3 细胞的侵袭和迁移能力，而这种增强作用在使用 siRNA 沉默 CCR7 时被显著阻断。Western blot 分析显示，当 UM-UC-3 细胞用 CCL21 处理时，磷酸化 ERK1/2 水平显著增加，而当 CCR7 基因沉默时，磷酸化 ERK1/2 水平显著降低。用 PD98059 抑制 MEK/ERK1/2 显著抑制了 UM-UC-3 细胞的迁移和侵袭能力，也显著阻断了 CCL21/CCR7 对细胞迁移和侵袭的影响。基于这些结果，我们得出结论，CCL21/CCR7 趋化作用的激活至少通过两种方式促进了膀胱癌的淋巴结转移。首先，尽管 CCR7 是一种促进淋巴管生成和血管生成的促进因子，但它可能通过其淋巴管生成作用而不是通过其血管生成作用促进淋巴结转移。其次，CCL21/CCR7 趋化作用通过 MEK/ERK1/2 信号通路而不是 PI3K/AKT 通路促进 UBC 细胞的迁移和侵袭。
