Abstract
A network composed of activation and inactivation pathways to regulate mitomycin C (MMC) action is suggested to exist in human cancer cells. COLO201 colon cancer cells were stably transfected with human NQO1 cDNA that encodes NAD(P)H: quinone oxidoreductase (DT‐diaphorase, DTD), and a clonal cell line with about 57‐fold elevated DTD activity was obtained. Northern analysis revealed that expression of the NADPH:cytochrome P450 reductase (P450 reductase) gene was decreased in the transfectant, COLO201/NQO1, associated with the increase of NQO1 expression. Biochemical characterization of the cells showed a significant increase of the glutathione (GSH) content concomitantly with the decrease of the P450 reductase activity. As a result of these coordinated modulations, sensitivity of COLO201/NQO1 to MMC was not increased as compared to the parent cells. Analyses of inhibition by specific inhibitors of DTD, P450 reductase and glutathione S‐transferase (GST) in 5 human colon cancer cell lines including the transfectant showed that DTD and P450 reductase play significant roles in MMC activation in cells with sufficiently high DTD activity and with marginal DTD activity, respectively. In contrast, GST appeared to participate in MMC inactivation in cells with a high level of GST activity. These results indicated that DTD, P450 reductase, GSH and GST may act together compensatively or competitively, depending on their levels in cells, to determine the cellular sensitivity to MMC.
Keywords: Colon cancer, Mitomycin C, NQO1, NADPH:cytochrome P450 reductase, Drug resistance
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REFERENCES
- 1).Crooke , S. T. and Bradner , M. T.Mitomycin C: a review . Cancer Treat. Rev. , 3 , 121 – 139 ( 1976. ). [DOI] [PubMed] [Google Scholar]
- 2).Workman , P.Enzyme‐directed bioreductive drug development revisited: a commentary on recent progress and future prospects with emphasis on quinone anticancer agents and quinone metabolizing enzymes, particularly DT‐diaphorase . Oncol. Res. , 6 , 461 – 475 ( 1994. ). [PubMed] [Google Scholar]
- 3).Nishiyama , M. , Suzuki , K. , Kumazaki , T. , Yamamoto , W. , Toge , T. , Okamura , T. and Kurisu , K.Molecular targeting of mitomycin C chemotherapy . Int. J. Cancer , 72 , 649 – 656 ( 1997. ). [DOI] [PubMed] [Google Scholar]
- 4).O'Dwyer , P. J. , Szarka , C. E. , Yao , K.‐S. , Halbherr , T. C. , Pfeiffer , G. R. , Green , F. , Gallo , J. M. , Brennan , J. , Frucht , H. , Goosenberg , E. B. , Hamilton , T. C. , Litwin , S. , Balshem , A. M. , Engstrom , P. F. and Clapper , M. L.Modulation of gene expression in subjects at risk for colorectal cancer by the chemopreventive dithiolethione oltipraz . J. Clin. Invest. , 98 , 1210 – 1217 ( 1996. ). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5).Kuo , M. T. , Bao , J.‐J. , Curley , S. A. , Ikeguchi , M. , Johnston , D. A. and Ishikawa , T.Frequent coordinated overexpression of the MRP/GS‐X pump and γ‐glutamylcysteine synthetase genes in human colorectal cancers . Cancer Res. , 56 , 3642 – 3644 ( 1996. ). [PubMed] [Google Scholar]
- 6).Saeki , S. , Nishiyama , M. and Toge , T.DT‐diaphorase as a target enzyme for biochemical modulation of mitomycin C . Hiroshima J. Med. Sci. , 44 , 55 – 63 ( 1995. ). [PubMed] [Google Scholar]
- 7).Jaiswal , A. K. , McBride , O. W. , Adesnik , M. and Nebert , D. W.Human dioxin‐inducible cytosolic NAD(P)H:mena‐dione oxidoreductase. cDNA sequence and localization of gene to chromosome 16 . J. Biol. Chem. , 263 , 13572 – 13578 ( 1988. ). [PubMed] [Google Scholar]
- 8).Kano , T. , Sakai , M. and Muramatsu , M.Structure and expression of a human class π glutathione S‐transferase messenger RNA . Cancer Res. , 47 , 5626 – 5630 ( 1987. ). [PubMed] [Google Scholar]
- 9).Roninson , I. B. , Chin , J. E. , Choi , K. , Gros , P. , Housman , D. E. , Fojo , A. , Shen , D.‐W. , Gottesman , M. M. and Pastan , I.Isolation of human mdr DNA sequences amplified in multidrug‐resistant KB carcinoma cells . Proc. Natl. Acad. Sci. USA , 83 , 4538 – 4542 ( 1986. ). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10).Cole , S. P. , Ghardwaj , G. , Gerlach , J. H. , Mackie , J. E. , Grant , C. E. , Almquist , K. C. , Stewart , A. J. , Kurz , E. U. , Duncan , A. M. and Deeley , R. G.Overexpression of a transporter gene in a multi‐resistant human lung cancer cell line . Science , 258 , 1650 – 1654 ( 1992. ). [DOI] [PubMed] [Google Scholar]
- 11).Shephard , E. A. , Palmer , C. N. , Segall , H. J. and Phillips , I. R.Quantification of cytochrome P450 reductase gene expression in human tissues . Arch. Biochem. Biophys. , 294 , 168 – 172 ( 1992. ). [DOI] [PubMed] [Google Scholar]
- 12).Ercolani , L. , Florence , B. , Denaro , M. and Alexander , M.Isolation and complete sequence of a functional human glyceraldehyde‐3‐phosphate dehydrogenase gene . J. Biol. Chem. , 263 , 15335 – 15341 ( 1988. ). [PubMed] [Google Scholar]
- 13).Belcourt , M. F. , Hodnick , W. F. , Rockwell , S. and Sartorelli , A. C.Differential toxicity of mitomycin C and porfiromycin to aerobic and hypoxic Chinese hamster ovary cells overexpressing human NADPH: cytochrome c (P‐450) reductase . Proc. Natl. Acad. Sci. USA , 93 , 456 – 460 ( 1996. ). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14).Mikami , K. , Naito , M. , Tomida , A. , Yamada , M. , Sirakusa , T. and Tsuruo , T.DT‐diaphorase as a critical determinant of sensitivity to mitomycin C in human colon and gastric carcinoma cell lines . Cancer Res. , 56 , 2823 – 2826 ( 1996. ). [PubMed] [Google Scholar]
- 15).Joseph , P. , Xu , Y. and Jaiswal , A. K.Non‐enzymatic and enzymatic activation of mitomycin C: identification of a unique cytosolic activity . Int. J. Cancer , 65 , 263 – 271 ( 1996. ). [DOI] [PubMed] [Google Scholar]
- 16).Singh , S. V. , Xu , B. H. , Maurya , A. K. and Mian , A. M.Modulation of mitomycin C resistance by glutathione transferase inhibitor ethacrynic acid . Biochim. Biophys. Acta , 1137 , 257 – 263 ( 1992. ). [DOI] [PubMed] [Google Scholar]
- 17).Siegel , D. , Beall , H. , Senekowitsch , C. , Kasai , M. , Arai , H. , Gibson , N. W. and Ross , D.Bioreductive activation of mitomycin C by DT‐diaphorase . Biochemistry , 31 , 7879 – 7885 ( 1992. ). [DOI] [PubMed] [Google Scholar]
- 18).Sharma , M. and Tomasz , M.Conjugation of glutathione and other thiols with bioreductively activated mitomycin C. Effect of thiols on the reductive activation rate . Chem. Res. Toxicol. , 7 , 390 – 400 ( 1994. ). [DOI] [PubMed] [Google Scholar]
- 19).O'Leary , K. A. , McQuiddy , P. and Kasper , C. B.Transcriptional regulation of the TATA‐less NADPH cytochrome P‐450 oxidoreductase gene . Arch. Biochem. Biophys. , 330 , 271 – 280 ( 1996. ). [DOI] [PubMed] [Google Scholar]