ICAM-1 supports adhesion of human small-cell lung carcinoma to endothelial cells

Adhesion of tumor cells to endothelium via cell-adhesion molecules constitutes a crucial step in metastasis, which is largely responsible for the poor prognosis of small-cell lung carcinoma (SCLC). Patients with SCLC were reported to have elevated levels of intercellular adhesion molecule-1 (ICAM-1). The present study therefore focusses on endothelial ICAM-1 in tumor-cell adhesion. We found that the adherence of SCLC cells (cell lines H24, H69, H82) to cultured vascular endothelium in stasis and flow depends on the expression of ICAM-1. After blocking endothelial ICAM-1 with monoclonal antibodies, adhesion was significantly reduced. These results pinpoint ICAM-1 for the first time as a molecule crucially involved in SCLC cell-endothelial adhesion.