Adriamycin Resistance in Human Tumor Cells Associated with Marked Alterations in the Regulation of the Hexose Monophosphate Shunt and Its Response to Oxidant Stress

Grace Chao Yeh, Sandra J. Occhipinti, Ken H. Cowan, Bruce A. Chabner, Charles E. Myers

Research output: Contribution to journalArticlepeer-review

49 Scopus citations

Abstract

We found that Adriamycin increased the pentose phosphate shunt activity in both Adriamycin-sensitive (WT) and Adriamycin-resistant (ADRR) human breast cancer MCF-7 cells. In contrast, hydrogen peroxide and cumene hydroperoxide markedly stimulated pentose-shunt activity in ADRR but only moderately increased the activity in WT cells. Furthermore, the altered oxidation-reduction regulation is associated with changes intrinsic to the key enzymes of the pentose-shunt pathway, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase and with glutathione peroxidase. We found the Vmax values for glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were 50- and 4-fold lower, respectively, in ADRR than WT cells and the Kma of NADP4 were 10-fold lower in ADRR than WT. The activity of glutathione reductase in ADRR is 42% of that in WT. In spite of these changes, the response of the cells to both hydrogen peroxide and organic peroxide is not limited by either the capacity of the pentose shunt or glutathione reductase, but is determined by the activity of glutathione peroxidase and a glutathione transferase which possess peroxidase activity. The kinetic properties of the glucose-6-phosphate dehydrogenase in ADRR may, however, seriously limit the activity of cytochrome P-450 reductase, a major enzyme of Adriamydn conversion to a free radical.

Original languageEnglish (US)
Pages (from-to)5994-5999
Number of pages6
JournalCancer Research
Volume47
Issue number22
StatePublished - 1987
Externally publishedYes

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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