The interaction of neoplastic cells with basement membrane molecules is the first step for the dissemination of tumor cells in vivo. Leukemic cells have a great ability to spread in the host, since cells are released from the bone marrow to the circulation. In this study we analysed whether CEM, U937, K562 and HL-60 cells were able to attach to different concentrations of laminin and/or fibronectin and/or type IV collagen. Attachment to type IV collagen was low, but it increased with the addition of laminin and occurred in all four leukemic cell lines. On the other hand, attachment to fibronectin was higher, but it decreased with the addition of laminin in the assays using U937 and HL-60 cells. The combination of type IV collagen and fibronectin was a good substratum for cellular attachment. However, the addition of laminin to this substratum impaired its attachment activity in U937, HL-60 and K562. These data suggest that laminin may control cellular attachment to the extracellular matrix during leukemic dissemination in hosts in different ways.
Leukemia; extracellular matrix; attachment; fibronectin; laminin; type IV collagen
