Loss of Metastatic Responsiveness to Cell Shape Modulation in a Newly Characterized B16 Melanoma Adhesive Cell Variant

Abstract

Repeated selection of an adherent subpopulation from B16-F1 melanoma cells growing in suspension culture on poly(hydroxyethylmethacrylate) [poly(HEMA)] coated plates resulted in the isolation of an adherent variant designated B16-A10. B16-A10 cells are more adherent to poly(hydroxyethylmethacrylate) coated plates than are B16-F1 cells and express an organized actin structure characteristic of highly adherent low metastatic cells as opposed to the poor cytoskeletal organization of B16-F1 cells. Upon growth in suspension, B16-A10 cells do not acquire the enhanced metastatic capability characteristic of B16-F1 cells and they express similar lung colonizing ability irrespective of the culture conditions. The increased metastatic ability of B16-F1 cells in suspension culture has previously been associated with the decreased accessibility of surface proteins to lactoperoxidase catalyzed iodination and with the increased expression of sialylated peanut agglutinin-binding oligosaccharides on these proteins. B16-A10 cells which show no cell shape induced increase in metastatic ability do not undergo alteration in either of these two properties in suspension culture. The absence of these two phenomena on B16-A10 cells grown in suspension indicates that they are interrelated and involved in the increased metastatic ability of B16-F1 cells grown in suspension.