Expression of chemokine receptor CCR7 is associated with cervical lymph node metastasis of oral squamous cell carcinoma

Abstract

Tumor cell migration and metastasis share many similarities with leukocyte trafficking, which is critically regulated by chemokines and their receptors. The present study was designed to examine the expression of chemokine receptor CCR7 in oral squamous cell carcinoma (OSCC), and to investigate the possible role of CCR7/CCL21 interaction in neck lymph node metastasis of OSCC. By using immunohistochemistry, RT-PCR and Western Blot, expression of CCR7 was examined in 85 cases of oral squamous cell carcinoma, and Tca8113 and ACC cell lines. CCL21-mediated cell migration was assayed in Matrigel-coated chemotaxis chamber. In vitro adhesion assay was shown for banding of tumor cell lines to submandibular lymph nodes with or without anti-CCR7 antibody treatment. Immunohistochemical staining showed 65.9% (56/85) of positive CCR7 expression in OSCC tissues. CCR7 expression was significantly higher in patients with lymph node metastasis compared with those without lymph node metastasis (P=0.015) and was also associated with tumor size (P=0.014), and clinical stage (P=0.009). RT-PCR and Western Blot also confirmed positive CCR7 expression in oral squamous cell carcinoma and Tca8113 cell line, and negative CCR7 expression in normal oral mucosa and ACC cell line. CCL21 stimulation increased the ability of CCR7-positive Tca8113 cells passing through the Matrigel membrane. CCR7-positive Tca8113 cells also showed stronger adhesion to lymph nodes, which could be partly blocked by anti-CCR7 antibody incubation. These results indicated that the chemotactic CCR7/CCL21 interaction may be a possible mechanism for induction of directional lymph node metastasis by oral squamous cell carcinoma.