METASTASIS OF ENTAMOEBA-HISTOLYTICA COMPARED TO COLON-CANCER - ONE MORE STEP IN INVASION

The multistep invasion process of metastasis is a well-conserved mecha nism of normal symbiosis and pathogenic parasitosis. To illustrate thi s statement, we have compared cellular and molecular aspects of metast asis from colon cancer and enteric amebiasis caused by Entamoeba histo lytica. Both types of pathogenic cell, cancer cells and amebic trophoz oites, follow the same metastatic route for the liver and other organs . Both establish invasion microecosystems implicating similar kinds of host cells and molecules belonging to closely related families. We ha ve recently found indications that molecules released by trophozoites immediately after adhesion to epithelial monolayers bind to elements o f the epithelial intercellular junctions. This phenomenon may lead to the functional disturbance of these junctions. Down-modulation of cell -cell adhesion molecules promotes invasion of colon cancer and other c ancer cells. It is our opinion that comparative studies of apparently unrelated systems may reveal cellular and molecular mechanisms of inva sion and metastasis that are of general biological importance.