67-kDa laminin receptor in human laryngeal squamous cell carcinoma

Abnormal interaction of epithelial cells with laminin component of basement membrane may account for altered biological behavior of cells, influencing proliferation, adhesion, and motility. In the current study, we investigated the role of 67-kDa laminin receptor (67LR), a high affinity receptor for laminin, in aggressiveness of laryngeal squamous cell carcinoma.

Thirty paraffin-embedded specimens and 20 fresh tissues of patients with laryngeal squamous cell carcinoma were analyzed using immunohistologic and reverse-transcriptase polymerase chain reaction techniques, respectively. Expression of 67LR on the surface of AMC-HN-8 cells was examined by flow cytometry. The effect of 67LR monoclonal antibody (MLuC5) on the adhesive and invasive abilities of AMC-HN-8 cells was determined by adherence and invasion inhibition assay in vitro.

Both at the mRNA and protein level, laryngeal carcinoma cells expressed higher level of 67LR than normal epithelial cells (P < .01). The expression of 67LR correlated inversely with differentiation extent of tumor (P < .05). 67LR level was significantly increased in patients with lymph node metastases than those without lymph node involvement (P < .05). Flow cytometry showed 80.9 +/- 0.9% of AMC-HN-8 cells expressed 67LR. After 60 minutes and 120 minutes of incubation, MluC5 induced 57.1 +/- 3.6% and 63.2 +/- 2.8% inhibition of adhesion, respectively. The invasive ability of AMC-HN-8 cells to matrigel was reduced by MLuC5.

Laryngeal carcinoma cells over-expressing 67LR have a stronger aggressive potential, which might make 67LR a promising target for the treatment of metastatic tumor.