5'-Nucleotidase activity and arachidonate metabolism in doxorubicin sensitive and resistant P388 cells

5'-nucleotidase activity, arachidonate metabolism and adenosine uptake were measured in P388 murine leukaemia cells and in a subline resistant to doxorubicin. These membranes related activities were found to be increased in the doxorubicin resistant cell line, compared to the drug sensitive cells. It is suggested that these differences do not play a role in the mechanism of resistance to doxorubicin. Rather they reflect alterations in plasma membrane composition and structure between these cell lines. This study also suggests that the use of decreased 5'-nucleotidase activity as a marker of certain leukaemias should be reviewed with caution. An increase in cell enzyme activity in treated patients may not necessarily indicate a shift toward normal behaviour of these cells, but rather a selection of certain cell subpopulations.