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NEAMATI ET AL.
ANTIMICROB. AGENTS CHEMOTHER.
2. Burke, Jr., T. R., M. R. Fesen, A. Mazumder, J. Wang, A. M. Carothers, G.
Grunberger, J. Driscoll, K. W. Kohn, and Y. Pommier. 1995. Hydroxylated
aromatic inhibitors of HIV-1 integrase. J. Med. Chem. 38:4171–4178.
3. Carteau, S., J. F. Mouscadet, H. Goulaouic, F. Subra, and C. Auclair. 1993.
Inhibitory effect of the polyanionic drug suramin on the in vitro HIV DNA
integration reaction. Arch. Biochem. Biophys. 305:606–610.
4. Chow, S. A., K. A. Vincent, V. Ellison, and P. O. Brown. 1992. Reversal of
integration and DNA splicing mediated by integrase of human immunode-
ficiency virus. Science 255:723–726.
5. Cushman, M., W. M. Golebiewski, Y. Pommier, A. Mazumder, D. Reymen,
E. De Clerq, L. Graham, and W. G. Rice. 1995. Cosalane analogs with
enhanced potencies as inhibitors of HIV-1 protease and integrase. J. Med.
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3.4 Ϯ 0.8 g/ml; IC50: 15.6 Ϯ 1.4 g/ml) was also confirmed to
be moderately potent in this assay. Although these two com-
pounds were inactive in our IN assay, they were effective in-
hibitors of HIV-1 reverse transcriptase (20). Interestingly, not
all compounds that exhibited high potency against reverse
transcriptase were confirmed active in cellular assays (1, 20).
We also did not observe a direct correlation between anti-IN
activities and in vitro activities in cellular assays.
DISCUSSION
6. De Benedetti, P. G. 1991. Molecular modeling and quantitative structure-
activity analysis of antibacterial sulfanilamides and sulfones. Prog. Drug Res.
36:361–417.
The mechanisms of cytotoxicity and anti-HIV-1, and anti-IN
activity remain a critical issue for this class of compounds and
all other inhibitors reported thus far. It seems possible to
identify critical factors necessary for IN activity in isolated
enzyme systems. Unfortunately, information gained in such
systems does not always translate to activities observed in cel-
lular assays. The question of whether anti-IN activity in iso-
lated enzyme systems correlates with general anti-HIV activity
remains. Studies from several laboratories have concluded that
in some instances, there is a good correlation between activi-
ties in isolated enzyme models and the in vitro cellular data
(see, for example, reference 27). However, there are many
reasons why isolated enzyme data do not necessarily translate
into cellular activity. In light of this, a more robust model system
needs to be evaluated, and toward this end we have been
engaging in several different studies to address this issue. For
example, we are exploring the site of enzyme-drug interaction,
using a photoaffinity probe (23). Several of our water-soluble
inhibitors will be evaluated in cocrystallization experiments
with the native enzyme for X-ray structure determinations. We
are also exploring inhibitory activities of the drugs against
several IN mutants.
7. De Benedetti, P. G. 1987. Structure-activity relationships and mechanism of
action of antibacterial sulphanilamides and sulfones. Adv. Drug Res. 16:227–
279.
8. De Clercq, E. 1995. Toward improved anti-HIV chemotherapy: therapeutic
strategies for intervention with HIV infections. J. Med. Chem. 38:2491–
2517.
9. Fesen, M., Y. Pommier, F. Leteurtre, S. Hiroguchi, J. Yung, and K. W. Kohn.
1994. Inhibition of HIV-1 integrase by flavones, caffeic acid phenethyl ester
(CAPE) and related compounds. Biochem. Pharmacol. 48:595–608.
10. Hong, Y.-L., P. A. Hossler, D. H. Calhoun, and S. T. Meshnick. 1995.
Inhibition of recombinant pneumocystis carinii dihydropteroate synthetase
by sulfa drugs. Antimicrob. Agents Chemother. 39:1756–1763.
11. Katz, R. A., and A. M. Skalka. 1994. The retroviral enzymes. Annu. Rev.
Biochem. 63:133–173.
12. LaFemina, R. L., P. L. Graham, K. LeGrow, J. C. Hastings, A. Wolfe, S. D.
Young, E. A. Emini, and D. J. Hazuda. 1995. Inhibition of human immuno-
deficiency virus integrase by bis-catechols. Antimicrob. Agents Chemother.
39:320–324.
13. Liehr, J. G., and D. Roy. 1990. Free radical generation by redox cycling of
estrogens. Free Radical Biol. Med. 8:415–423.
14. Lopez de Compadre, R. L., R. A. Pearlstein, A. J. Hopfinger, and J. K.
Seydel. 1987. A quantitative structure-activity relationship analysis of some
4-aminodiphenyl sulfone antibacterial agents using linear free energy and
molecular modeling methods. J. Med. Chem. 30:900–906.
15. Matsukawa, T., B. Ohta, and T. Imada. 1950. Syntheses of sulfide and
sulfone compounds. III. Syntheses of diphenyl sulfone compounds. J. Pharm.
Soc. Jpn. 70:77–80.
Comparative analysis of a panel of structurally similar sul-
fones has revealed several factors contributing to the mecha-
nisms of anti-HIV-1 IN activity of this class of compounds. For
example, replacement of one hydroxyl group with an amino,
thiol, aldehyde, or carboxyl group resulted in no loss of po-
tency. However, electron-withdrawing groups such as nitro and
fluoro groups influence IN inhibitory potency. Interestingly,
precedents in the literature suggest that the electronic nature
of substituents on the phenyl ring greatly influences the anti-
bacterial and antimalarial activities of sulfones (6, 7, 14).
The findings of the present study could have important im-
plications for the designing of more potent sulfone-based in-
hibitors. For example, compounds containing a mercapto
group adjacent to an amino, hydroxyl, or carboxyl group ought
to have anti-IN activity. Presently, we are engaged in synthe-
sizing novel compounds based on sulfones and other inhibitors
to obtain an optimal IN inhibitor.
16. Mazumder, A., K. Raghavan, J. Weinstein, K. W. Kohn, and Y. Pommier.
1995. Inhibition of human immunodeficiency virus type-1 integrase by cur-
camin. Biochem. Pharmacol. 49:1165–1170.
17. Mazumder, A., A. Gazit, A. Levitzki, M. Nicklaus, J. Yung, G. Kohlhagen,
and Y. Pommier. 1995. Effects of tyrphostins, protein kinase inhibitors, on
human immunodeficiency virus type 1 integrase. Biochemistry 34:15111–
15122.
18. Mazumder, A., N. Neamati, J.-P. Sommadossi, G. Gosselin, R. F. Schinazi,
J.-L. Imbach, and Y. Pommier. 1996. Effects of nucleotide analogs on human
immunodeficiency virus integrase. Mol. Pharmacol. 49:621–628.
19. Mazumder, A., S. Wang, N. Neamati, M. Nicklaus, S. Sunder, J. Chen,
G. W. A. Milne, W. G. Rice, T. R. Burke, Jr., and Y. Pommier. 1996.
Antiretroviral agents as inhibitors of both human immunodeficiency virus
type 1 integrase and protease. J. Med. Chem. 39:2472–2481.
20. McMahon, J. B., R. J. Gulakowski, O. S. Weislow, R. J. Schultz, V. L.
Narayanan, D. J. Clanton, R. Pedemonte, F. W. Wassmundt, R. W. Buckheit,
Jr., W. D. Decker, E. L. White, J. P. Bader, and M. R. Boyd. 1993. Diaryl-
sulfones, a new chemical class of nonnucleoside antiviral inhibitors of human
immunodeficiency virus type 1 reverse transcriptase. Antimicrob. Agents
Chemother. 37:754–760.
21. Mironov, G. S., V. V. Vetrova, and M. I. Farberov. 1969. Synthesis of diaryl
sulfones and polycarboxylic acids based on them. Izv. Vyssh. Uchebn. Zaved.
Khim. Khim. Tekhnol. 12:1588–1593.
22. Mouscadet, J. F., S. Carteau, H. Goulaouic, F. Subra, and C. Auclair. 1994.
Triplex-mediated inhibition of HIV DNA integration in vitro. J. Biol. Chem.
269:21635–21638.
23. Neamati, N., P. Sunthankar, A. Mazumder, N. King, S. D. Hume, Y. Pom-
mier, and R. R. Drake. Proteolytic mapping identification of the azidothy-
midine monophosphate binding site of human immunodeficiency virus
type-1 integrase. Submitted for publication.
24. Pommier, Y., G. Kohlhagen, K. W. Kohn, F. Leteurtre, M. C. Wani, and
M. E. Wall. 1995. Interaction of an alkylating camptothecin derivative with
a DNA base at topoisomerase I-DNA cleavage sites. Proc. Natl. Acad. Sci.
USA 92:8861–8865.
ACKNOWLEDGMENTS
The assistance of the staff of the Drug Synthesis and Chemistry
Branch, NCI, is gratefully acknowledged. We also thank T. Jenkins and
R. Craigie (Laboratory of Molecular Biology, NIDDK, NIH) for the
mutant HIV IN proteins and the expression system for wild-type HIV
IN. We are also indebted to K. W. Kohn for stimulating discussion and
assistance during the course of this study.
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