Comparative adhesion of human haemopoietic cell lines to extracellular matrix components, bone marrow stromal and endothelial cultures

Abstract

Summary. We used flow cytometry to characterize cell adhesion molecule expression of the human haemopoietic cell lines KG1a, K562, HL-60, NALM-6 and CEM. A 51 chromium labelling assay was used to study the adhesion of these cell lines to extracellular matrix components and to bone marrow stromal and endothelial cultures. Both adhesion molecule expression and functional binding behaviour varied between cell lines. All five cell lines expressed the integrins a 4 b 1 and a 5 b 1 and all adhered to fibronectin. However, differences in intensity of expression of these integrins failed to correlate with extent of fibronectin adhesion. Inhibition experiments demonstrated that adhesion of KG1a to fibronectin was completely inhibited by divalent cation chelation and partially inhibited by RGDS peptides and chondroitinase ABC, suggesting that both a 4 b 1 and a 5 b 1 as well as CD44 were responsible for this interaction. Adhesion to bone marrow stromal and endothelial layers was superior to that to purified extracellular matrix components and was partially inhibited by divalent cation chelation. RGD peptides and anti-a 4 monoclonal antibody also partially inhibited KG1a adhesion to bone marrow endothelium.Discordance between cell adhesion molecule expression and adhesive behaviour suggest that current phenotypic descriptions remain incomplete and reinforce the need for complementary functional binding studies.

CXCR4 chemokine receptors (CD184) and α4β1 integrins mediate spontaneous migration of human CD34+ progenitors and acute myeloid leukaemia cells beneath marrow stromal cells (pseudoemperipolesis)

“…Pseudoemperipolesis has been described earlier for B-and T-lineage cell migration beneath marrow stroma or synovial fibroblasts (Hiai et al, 1981;Hewson et al, 1996;Takeuchi et al, 1999;Bradstock et al, 2000), and has been demonstrated to involve a4b1 and a5b1 (VLA-4, VLA-5 or CD49d, CD49e) integrin binding to corresponding stromal ligands (fibronectin and VCAM-1) (Miyake et al, 1992). The importance of a4b1 and a5b1 integrins in heterotypic adherence between precursor cell lines (pre-B Nalm-6 and multipotential UT-7) and marrow stromal cells has been demonstrated by several investigators (Ryan et al, 1991;Patrick et al, 1995;Robledo et al, 1998;Turner et al, 1998), but the molecular mechanism of haematopoietic stem cell migration beneath stromal cells has not yet been defined. It has been noted, however, that integrins alone mediate only the initial attachment of precursor or AML cells to stroma, but are not sufficient for the retention or subsequent migration beneath the stromal cells (Miyake et al, 1992;Bendall et al, 1993;Patrick et al, 1995).…”

An in vitro model of hematopoietic stem cell homing demonstrates rapid homing and maintenance of engraftable stem cells

“…Most in vitro homing studies examine adhesion of a hematopoietic cell population or cell line to a test substrate, such as purified extracellular matrix molecule coatings or stromal cell lines, under various conditions. [20][21][22][23][24][25][26][27][28][29] While these systems are more manageable, they do not accurately reflect the in vivo condition. Further, the outcome is most often measured by counting adherent cells, or counting cells remaining in the supernatant and subtracting them from the total, and this is limiting because it is impossible to determine the functionality of the adhered cells.…”

Hyaluronan Synthase Elevation in Metastatic Prostate Carcinoma Cells Correlates with Hyaluronan Surface Retention, a Prerequisite for Rapid Adhesion to Bone Marrow Endothelial Cells

“…In fact, tumor cells have been shown to bind and transmigrate through BMEC (17)(18)(19). The adhesion molecules implicated in these processes, CD44/hyaluronan, VLA-4/VCAM, and LFA-1/ICAM, are also involved in homing and extravasation of circulating lymphocytes and progenitor cells.…”