Drug effects on certain enzymes of carbohydrate metabolism in MCF-7 cells in culture.

The effects of treatments with ethinyl-estradiol, tamoxifen, prednisolone, cyclophosphamide, methotrexate, 5-fluorouracil and Adriamycin on the activities of PFK, 6PGDH, alpha-GPDH and alpha-GPDH/6PGDH ratios were investigated in MCF-7 cells in monolayer cultures. The following findings are recorded. Both ethinyl-estradiol and prednisolone failed to induce alterations in the activities of these enzymes. Tamoxifen increased the activities of PFK, alpha-GPDH and alpha-GPDH/6PGDH ratios whereas ethinyl-estradiol inhibited the tamoxifen-induced rise in the activity of PFK. Treatment with cyclophosphamide alone was without any effect but in combination with either methotrexate or 5-fluorouracil induced increases in the activities of 6PGDH and alpha-GPDH. Adriamycin at a lower dose increased the activities of 6PGDH and alpha-GPDH and the alpha-GPDH/6PGDH ratio and decreased the activity of PFK. At a higher dose level it reduced the activities of all the enzymes whilst increasing the alpha-GPDH/6PGDH ratio. These data encourage us to undertake a project to test the sensitivity of individual tumours to these drugs in vitro thereby enabling the selection of appropriate drugs for adjuvant therapy.