adenosine deaminase activity in estrogen receptor positive and negative human breast cancer cell lines

abstract background: the aims of this study were to assay the activity of adenosine deaminase (ada) in estrogen receptor positive (mcf-7) and negative (mda-mb468) breast cancer cell lines. methods: mda-mb468 and mcf-7 breast cancer cell lines were cultured in complete medium, striped serum with and without 0.0 1~-lm diethylstilbestrol (des), complete medium in the presence and absence of 111m tamoxifen for 20 hr. adenosine deaminase activity was determined using the colorimetric method described by guisti and galanti. results: it was found that the activity of enzyme in estrogen receptor positive (er+) cell line (mcf-7) was significantly higher than that of estrogen receptor negative breast cancer cell line (mda-mb468). ada activity in mcf-7 cells cultured in the presence of tamoxifen or charcoal-striped serum was significantly lower than that of control. furthermore addition of diethylstilbestrol (des) to the striped serum increased the value of ada activity to that of control. unlike mcf-7 cells, the activity of ada in mda-mb468 cells remained unchanged upon treatment with tamoxifen or striped serum. conclusion: these findings suggest estrogen responsiveness of ada expression in mcf-7 cells.