ACS Medicinal Chemistry Letters
LETTER
with DOXO alone. A number of reactive nitrogen species,
generated under different conditions and environments, can
mediate this nitration. The amount of nitro tyrosine produced
by 5 appeared greater than that produced by 4. This result is in
keeping with the higher levels of nitrite detected with 5. Also, the
intracellular accumulation of DOXO with 5 was higher than with
4. It is known that DOXO up-regulates the inducible isoform of
NO synthase (iNOS),15 thereby increasing the endogenous syn-
thesis of NO in mammalian cells. Thus, it is possible that the
nitration of MRP3 elicited by 4 and 5 is due in part to the release
of NO by the products and in part to the increased production of
endogenous NO via the induction of the iNOS enzyme. No
nitration occurred in P-gp protein. Both P-gp and MRP3 are
involved in DOXO efflux, depending on the different tissues and
on the relative abundance of the transporters in tumor cells.3
Because the treatment with the NO donor compounds 3 and 7
did not modify the activity of P-gp in HT29-dx cells (see the
rhodamine 123 test in the Supporting Information), we have to
conclude that this transporter does not play a primary role in the
effect exerted by NO on DOXO retention. This is most likely due
to the lower number of tyrosine residues of the transporter with
respect to MRP3 and/or to its lower expression.7,16
(3) Gottesman, M. M.; Fojo, T.; Bates, S. E. Multidrug resistance in
cancer: Role of ATP-dependent transporters. Nat. Rev. Cancer 2002,
2, 48–58.
(4) Colabufo, N. A.; Berardi, F.; Cantore, M.; Contino, M.; Inglese,
C.; Niso, M.; Perrone, R. Perspectives of P-glycoprotein modulating
agents in oncology and neurodegenerative diseases: Pharmaceutical,
biological, and diagnostic potentials. J. Med. Chem. 2010, 53, 1883–
1897 and references therein.
(6) T€urk, D.; Hall, M. D.; Chu, B. F.; Ludwig, J. A.; Fales, H. M.;
Gottesman, M. M.; Szakꢀacs, G. Identification of compounds selectively
killing multidrug-resistant cancer cells. Cancer Res. 2009, 69, 8293–8301.
(7) Riganti, C.; Miraglia, E.; Viarisio, D.; Costamagna, C.; Pescar-
mona, G.; Ghigo, D.; Bosia, A. Nitric oxide reverts the resistance to
doxorubicin in human colon cancer cells by inhibiting the drug efflux.
Cancer Res. 2005, 65, 516–525.
(8) Gasco, A.; Schoenafinger, K. The NO-releasing heterocycles. In
Nitric Oxide Donors; Wang, P. G., Cai, T. B., Taniguchi, N., Eds.; Wiley-
VCH Verlag GmbH & Co KGaA: Weinheim, 2005; pp 131ꢀ175.
(9) Fruttero, R.; Crosetti, M.; Chegaev, K.; Guglielmo, S.; Gasco, A.;
Berardi, F.; Niso, M.; Perrone, R.; Panaro, M. A.; Colabufo, N. A.
Phenylsulfonylfuroxans as modulators of multidrug-resistance asso-
ciated protein-1 and P-glycoprotein. J. Med. Chem. 2010, 53, 5467–5475.
(10) Matthews, N. E.; Adams, M. A.; Maxwell, L. R.; Gofton, T. E.;
Graham, C. H. Nitric oxide-mediated regulation of chemosensitivity in
cancer cells. J. Natl. Cancer I 2001, 93, 1879–1885.
The preliminary results disclosed in the present work show
that the design of hybrid NO donor antitumor drugs could be a
useful strategy to address the problem of MDR in cancer therapy.
(11) Frederiksen, L. J.; Siemens, D. R.; Heaton, J. P.; Maxwell, L. R.;
Adams, M. A.; Graham, C. H. Hypoxia induced resistance to doxorubicin
in prostate cancer cells is inhibited by low concentrations of glyceryl
trinitrate. J. Urol. 2003, 170, 1003–1007.
’ ASSOCIATED CONTENT
(12) Mayer, B.; Beretta, M. The enigma of nitroglycerin bioactiva-
tion and nitrate tolerance: News, views and troubles. Br. J. Pharmacol.
2008, 155, 170–184.
(13) Daiber, A.; Wenzel, P.; Oelze, M.; Munzel, T. New insights into
bioactivation of organic nitrates, nitrate tolerance and cross-tolerance.
Clin. Res. Cardiol. 2008, 97, 12–20.
S
Supporting Information. Syntheses and characterization
b
data for the compounds and procedures for biological assays.
This material is available free of charge via the Internet at http://
pubs.acs.org.
(14) Grossi, L. Nitrite anion: The key intermediate in alkyl nitrates
degradative mechanism. J. Med. Chem. 2008, 51, 3318–3321.
(15) Aldieri, E.; Bergandi, L.; Riganti, C.; Costamagna, C.; Bosia, A.;
Ghigo, D. Doxorubicin induces an increase of nitric oxide synthesis in rat
cardiac cells that is inhibited by iron supplementation. Toxicol. Appl.
Pharmacol. 2002, 185, 85–90.
’ AUTHOR INFORMATION
Corresponding Author
*Tel: þ39 011 6707850. Fax: þ39 011 6707286. E-mail: roberta.
(16) Doublier, S.; Riganti, C.; Voena, C.; Costamagna, C.; Aldieri,
E.; Pescarmona, G.; Ghigo, D.; Bosia, A. RhoA silencing reverts the
resistance to doxorubicin in human colon cancer cells. Mol. Cancer Res.
2008, 6, 1607–1620.
’ ACKNOWLEDGMENT
We are indebted to Istituto Zooprofilattico Sperimentale del
Piemonte, Liguria e Valle d'Aosta, for mass spectral data.
’ ABBREVIATIONS
DOXO, doxorubicin; NO, nitric oxide; MDR, multidrug resistance;
P-gp, P-glycoprotein; ABC, ATP binding cassette; SNAP, S-nitroso-
penicillamine; SNP, sodium nitroprusside; GSNO, S-nitrosoglu-
tathione; ODQ, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one; sGC,
soluble guanylate cyclase; Rp-8-Br-cGMPS, 8-bromoguanosine-30,50-
cyclic monophosphorothioate; 8-Br-cGMP, 8-bromoguanosine cyclic
monophosphate;cGMP, guanosine-30,50-cyclicmonophosphate;
MDCK cells, MadinꢀDarby canine kidney cells; mtALDH, mi-
tochondrial aldehyde dehydrogenase
’ REFERENCES
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(2) Szakacs, G.; Paterson, J. K.; Ludwig, J. A.; Booth-Genthe, C.;
Gottesman, M. M. Targeting multidrug resistance in cancer. Nat. Rev.
Drug Discovery 2006, 5, 219–234.
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