The use of hydrogen peroxide to enhance the efficacy of doxorubicin hydrochloride in a murine bladder tumor cell line.
OBJECTIVE
We determined whether the cytotoxicity of doxorubicin hydrochloride would be enhanced by adding hydrogen peroxide as a source of oxygen free radicals.


METHODS
Mouse bladder tumor cells (MBT-2) were grown in RPMI 1640 medium and treated with various concentrations of doxorubicin hydrochloride for 2 hours. Protein content was assayed as a measure of cell growth. A similar set of experiments was done with cells exposed to hydrogen peroxide only and combined doxorubicin and hydrogen peroxide. Protein content was again assayed as a measure of cell growth. Cells were also assayed for glutathione peroxidase and malonyl dialdehyde, a product of lipid peroxidation, to determine the mechanism of cell damage. Furthermore, MBT-2 cells were incubated with 100 M. alpha-tocopherol, a free radical scavenger, before exposure to hydrogen peroxide to determine whether the effects of hydrogen peroxide could be reversed.


RESULTS
We observed a dose dependent inhibition of MBT-2 cell growth after exposure to doxorubicin hydrochloride. Exposure to doxorubicin and hydrogen peroxide resulted in greater cell growth inhibition than exposure to either agent alone. The effects of hydrogen peroxide on cell proliferation were reversed by pre-incubation with alpha-tocopherol.


CONCLUSIONS
As a source of oxygen free radicals, hydrogen peroxide enhances the antiproliferative effect of doxorubicin hydrochloride on a mouse bladder tumor cell line. Thus, hydrogen peroxide may be a relatively inexpensive, nontoxic method of augmenting the cytotoxicity of doxorubicin hydrochloride. Further studies are warranted to determine whether these observations may have clinical application.
Loughlin
K R
KR
Division of Urology, Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Manson
K
K
Cragnale
D
D
Wilson
L
L
Ball
R A
RA
Bridges
K R
KR
D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D016923:Cell Death / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000627:therapeutic use*; D004357:Drug Synergism; D016166:Free Radical Scavengers; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D015227:Lipid Peroxidation; D051379:Mice; D008809:Mice, Inbred C3H; D014407:Tumor Cells, Cultured; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy* / Q000503:physiopathology
D000970:Antineoplastic Agents; D016166:Free Radical Scavengers; D004317:Doxorubicin; D006861:Hydrogen Peroxide