Abstract 3306: Involvement of chemokine receptor CCR7 in lymph node metastasis and poor prognosis in esophageal squamous cell carcinoma
Authors: Irino Tomoyuki , Takeuchi Hiroya , Matsuda Sachiko , Saikawa Yoshiro , Ueda Masakazu , Kitagawa Yuko 
Published: February 2011

Abstract
[Purpose] Previous reports suggest that chemokine receptor CCR7 may be involved in lymph node metastasis, but it remains unclear what an important role CCR7 expression plays in patients with esophageal squamous cell carcinoma (ESCC) because we have so far only a few reports available. Here, we investigated how CCR7-expressing cells behaved in response to its specific ligand CCL21/SLC in vitro and vivo and analyzed clinicopathological relationship in patients with ESCC.
[Materials and Methods] Before starting experiments, we assessed CCR7 mRNA in 10 ESCC cell lines (TE series) by quantitative RT-PCR and subsequently adopted TE4 for further functional studies. Additionaly, we generated a modified TE4 cell line that overexpressed CCR7 (TE4CCR7+). First, we performed a cell migration assay using EZ-TAXIScan®, a cell mobility analyzer which enables us to observe migrating cells directly by a CCD camera. TE4 cells were seeded into a chamber containing serum-free medium with 300 ng/ml of CCL21/SLC and filmed every 3 minutes for 12 hours. Next, we examined how the CCR7-expressing cells behaved in vivo using lymph node metastatic model mice. The model mice were developed as follows: 1) subcutaneously growing tumors were established by injecting 1×107 tumor cells of native TE4 and TE4CCR7+ in nude mice, 2) the tumors were excised and a small piece of which was transplanted in the cubitals of other nude mice, 3) axillary lymph nodes were excised and examined three, four, five and six weeks after transplantation in which metastatic cells were detected by quantitative RT-PCR using a human ALU sequence. In a clinicopathological study, we analyzed 105 ESCC specimens with immunohistochemical staining, which specimens were obtained from patients who had undergone radical esophagectomy in our hospital during 1997 to 2002.
[Results] The cell migration assay showed increased cell migration ability in CCR7-expressing cells. A VD plot analysis of the assay revealed a significant increase in cell motility. The mice transplanted with TE4CCR7+ cells developed lymph node metastases precociously compared with the mice with native TE4 cells. In the clinicopathological analysis, two researchers found CCR7 expression in 28 patients (27%), which positive expression was significantly associated with lymph node metastasis (p=0.04), five-year recurrence-free rate (positive 25% vs negative 52%, p&lt;0.01) and five-year survival rate (25% vs 51%, p=0.02).
[Conclusion] These results strongly suggest that CCR7, in part, plays a critical role in lymph node metastasis and subsequent poor prognosis in patients with ESCC. CCR7-targeted therapy can be one of promising treatments for lymph node metastasis.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3306.