Loss of VLA-3 (CD49c/CD29) expression in two multidrug resistant Burkitt's lymphoma cell lines.

Expression of P-glycoprotein (P-gp) mediated multidrug resistance (MDR) has been suggested to be associated with an impaired clinical outcome in several malignancies. In contrast to P-gp itself, further phenotypical and functional alterations related to MDR are poorly characterized. In this in vitro study, we analyzed two Burkitt's lymphoma cell lines (Raji and Daudi) for the beta 1 integrin phenotype prior to and after induction of MDR via co-cultivation with vincristine. A significant loss of the VLA-3 (CD49c/CD29) adhesion receptor was observed whereas all other intergins analyzed lacked considerable changes. We conclude that induction of P-gp mediated MDR does not only affect resistance to cytotoxic drugs but also induces cellular changes with potential relevance for migratory and/or adhesive properties of malignant cells.