A New Endothelial Molecule Involved in Melanoma Cell Binding to Human Dermal Microvascular Endothelial Cells

Lee, Kwang Hoon; Chung, Kee Yang; Lawley, Thomas J; Swerlick, Robert A

Abstract

BACKGROUND
We have previously demonstrated that phorbol myristate acetate (PMA)-induced increases in melanoma cell binding to endothelial cells derived from human dermis (HDMEC) are not mediated via known cell adhesion molecules and may be affected through microvessel-specific novel proteins not previously described on endothelial cells.
OBJECTIVE
This study was performed to identify new molecules which may play a role in HDMEC-melanoma cells binding.
METHODS
We have generated a monoclonal antibody(Mab) against PMA-stimulated HDMEC. A Mab was evaluated functionally through melanoma cell-endothelial cell adherence assay and characterized by Western immunoblot.
RESULTS
Mab EM-71 recognized a molecule with expression levels in vitro that could be upregulated by PMA(EM-71 molecule). The expression of EM-71 molecule on HDMEC was increased in a dose-dependent manner by PMA only, but not affected by interleukin 1 alpha(IL-lÎ±) or tumor necrosis factor alpha(TNFÎ±) PMA augmented melanoma cell adherence to HDMEC, which is coincident with an increase in EM-71 molecule expression on HDMEC by PMA. Mab EM-71 partially inhibited up to 59% of the increased melanoma cell binding to PMA-stimulated HDMEC and failed to block melanoma cell binding to IL-lÎ± or TNFÎ±-stimulated HDMEC. Western immunoblots of lysates of HDMEC demonstrated a 200 kDa protein on HDMEC.
CONCLUSION
This study demonstrates that EM-71 molecule may play a partial role in melanoma binding to PMA-stimulated HDMEC.