Abstract

Recirculation of normal and neoplastic lymphocytes occurs via binding to the endothelial luminar surface, followed by extravasation and the subsequent interaction of the cells with components of the underlying basement membrane and stromal extracellular matrix (ECM). To identify matrix constituents that could be involved in the tissue dissemination of neoplastic B cells, we have examined the ability of three lymphoma B- cell lines and one Philadelphia chromosome (Ph1)-positive cell line established from the lymphoid transformation of a chronic myeloid leukemia (CML) to adhere to a range of purified ECM molecules. Immunophenotyping with a panel of markers suggested that the lines derived from cells that had undergone transformation at distinct stages of B-cell maturation. The four cell lines displayed a differential ability to adhere to the ECM molecules tested. BV-173, Ci-1, and Sc-1 cells attached to various degrees to fibronectin (FN). Ri-1, Ci-1, and Sc-1 cells attached to human laminin (LN) variants, whereas only Ci-1 and Sc-1 cells showed some affinity for collagen (Col) type VI. All four cell lines interacted with fibrillar Col I, but only BV-173 and Ri- 1 cells attached to fibrillar Col III. The subendothelial Col VIII only was active as a substratum for BV-173 cells. In all cases, cells bound to fibrillar collagens when they were assembled into polymeric fibrils, and were incapable of adhering to monomeric and denatured collagen. In contrast to cell adhesion to FN and LN, which showed a plateau at high substrate concentrations, adhesion to fibrillar Col I reached a peak at intermediary concentrations and decreased thereafter, suggesting that cells respond to a definite macromolecular arrangement of collagenous fibrils. Adhesion to individual ECM molecules was not directly correlated with the apparent maturation state of the cells, nor with the relative density of known ECM receptors. Taken together, these results suggest that interaction of neoplastic B cells with selected matrix components may influence their dispersion throughout tissues. We further suggest that the use of quantitative cell adhesion assays in vitro may provide means of defining the behavioral traits of neoplastic B cells in vivo.

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