Propensity for macrophage apoptosis is related to the pattern of expression and function of integrin extracellular matrix receptors

Ligation of integrins to an extracellular matrix activates signal transduction systems which produce multiple responses in different cell types. Adhesion often provides a survival signal to cells; disruption of adhesion frequently results in apoptosis. Our laboratory has utilized apoptosis-sensitive and -resistant cell lines to investigate the role of integrin expression and function in regulation of apoptosis in macrophages. Chronic exposure of murine macrophage-like RAW264.7 cells to apoptosis inducing agents (bacterial lipopolysaccharide and interferon-γ) resulted in the generation of a derivative cell line (RES) resistant to apoptosis. Observation of RAW and RES cultures indicated a difference in adhesion between the two cell types. The two cell lines also exhibit significant differences in expression of integrins previously characterized to be important in apoptosis.