Heat-induced up-regulation of NAD(P)H:quinone oxidoreductase potentiates anticancer effects of beta-lapachone.
OBJECTIVE
The purpose of the present study was to evaluate the efficacy of mild hyperthermia to potentiate the anticancer effects of beta-lapachone (3,4-dihydro-2,2-dimethyl-2H-naphthol[1,2-b]pyran-5,6-dione) by up-regulating NAD(P)H:quinone oxidoreductase (NQO1) in cancer cells.


METHODS
Effects of beta-lapachone alone or in combination with mild heating on the clonogenic survival of FSaII fibrosarcoma cells of C3H mice and A549 human lung tumor cells in vitro was determined. Effects of heating on the NQO1 level in the cancer cells in vitro were assessed using Western blot analysis for NQO1 expression, biochemical determination of NQO1 activity, and immunofluorescence microscopy for NQO1 expression. Growth of FSaII tumors in the hind legs of C3H mice was determined after treating the host mice with i.p. injection of 45 mg/kg beta-lapachone followed by heating the tumors at 42 degrees C for 1 hour every other day for four times.


RESULTS
Incubation of FSaII tumor cells and A549 tumor cells with beta-lapachone at 37 degrees C reduced clonogenic survival of the cells in dose-dependent and incubation time-dependent manner. NQO1 level in the cancer cells in vitro increased within 1 hour after heating at 42 degrees C for 1 hour and remained elevated for >72 hours. The clonogenic cell death caused by beta-lapachone increased in parallel with the increase in NQO1 levels in heated cells. Heating FSaII tumors in the legs of C3H mice enhanced the effect of i.p.-injected beta-lapachone in suppressing tumor growth.


CONCLUSIONS
We observed for the first time that mild heat shock up-regulates NQO1 in tumor cells. The heat-induced up-regulation of NQO1 enhanced the anticancer effects of beta-lapachone in vitro and in vivo.
Park
Heon Joo
HJ
Radiobiology Laboratory, Department of Therapeutic Radiology/Radiation Oncology, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Choi
Eun Kyung
EK
Choi
Jihyung
J
Ahn
Ki-Jung
KJ
Kim
Eun Jung
EJ
Ji
In-Mi
IM
Kook
Yeon Hee
YH
Ahn
Seung-Do
SD
Williams
Brent
B
Griffin
Robert
R
Boothman
David A
DA
Lee
Chung K
CK
Song
Chang W
CW
D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D016923:Cell Death; D045744:Cell Line, Tumor; D003131:Combined Modality Therapy; D001728:Dicumarol / Q000627:therapeutic use; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D006979:Hyperthermia, Induced; D051379:Mice; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009285:Naphthoquinones / Q000627:therapeutic use*; D009369:Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000628:therapy*; D015854:Up-Regulation
D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D009285:Naphthoquinones; C014638:beta-lapachone; D001728:Dicumarol; D016660:NAD(P)H Dehydrogenase (Quinone)