C O M M U N I C A T I O N S
(7) Wang, J. S.; Le, N.; Heredia, A.; Song, H. J.; Redfield, R.; Wang, L. X.
Org. Biomol. Chem. 2005, 3, 1781–1786.
because of their low propensity for immunogenicity, high
metabolic stability, ready large-scale production, and relatively
low cost. Small-molecule antibody-recruiting therapeutics such
as ARM-H would have additional benefits over available
treatment approaches to HIV. For example, directing HIV-
infected cells and virus particles to Fcγ receptors on antigen-
presenting cells could enhance the presentation of viral antigens
on MHC proteins and contribute to long-lasting anti-HIV
immunity.26,35 Furthermore, because anti-DNP antibodies are
already present in the human bloodstream, no pre-vaccination
would be necessary for ARM-H activity. Also, the binding of
bifunctional small-molecule targeting agents to antibodies should
prolong their plasma half-life, thus increasing their effective-
ness.27 Elucidation of the molecular details governing the
interactions among ARM-H, gp120, and anti-DNP antibodies
will assist in optimization efforts as well as in the evaluation of
this strategy in more complex biological models for HIV
infection. These and other investigations are currently ongoing
in our laboratories.
(8) Kong, R.; Tan, J.; Ma, X.; Chen, W.; Wang, C. Biochim. Biophys. Acta
2006, 1764, 766–772.
(9) Rostovtsev, V. V.; Green, L. G.; Fokin, V. V.; Sharpless, K. B. Angew.
Chem., Int. Ed. 2002, 41, 2596–2599.
(10) Tornøe, C.; Christensen, C.; Meldal, M. J. Org. Chem. 2002, 67, 3057–
3064.
(11) Ho, H.; et al. J. Virol. 2006, 80, 4017–4025.
(12) The increase in potency of BMS-378806 in MT-2 cells versus ELISAs
may be the result of a cooperative enhancement in binding to viral envelope
gp120, which exists as a trimer (ELISA studies were performed using
monomeric gp120). The steric bulk of ARM-H due to the C4 tether may
impede binding of more than one ARM-H molecule per gp120 trimer.
(13) More details regarding assay conditions and troubleshooting can be found
in the Supporting Information.
(14) Weiss, C.; White, J. J. Virol. 1993, 67, 7060–7066.
(15) Because it was necessary to permeabilize the cells prior to labeling,
intracellular gp120 can also be observed in these micrographs.
(16) Aasa-Chapman, M. M. I.; Holuigue, S.; Aubin, K.; Wong, M.; Jones, N. A.;
Cornforth, D.; Pellegrino, P.; Newton, P.; Williams, I.; Borrow, P.;
Mcknight, A. J. Virol. 2005, 79, 2823–2830.
(17) Gerencer, M.; Burek, V.; Crowe, B. A.; Barrett, N. P.; Dorner, F. Microb.
Pathog. 1998, 25, 253–266.
(18) The modest levels of complement-dependent cytotoxicity observed for
ARM-H in Figure 4 are similar to values reported in other systems (see
ref 34) and may result from the low levels of Env expression on the CHO-
gp120 cells (see ref 14). Also, because of assay incompatibilities, CDC
data corresponding to ARM-H concentrations greater than 30 µM could
not be obtained. More details can be found in the Supporting Information.
(19) Characteristic autoinhibition of ternary complex formation at high levels
of bifunctional molecule, arising from excess free bifunctional material
that drives the equilibria toward formation of binary complexes, was
not reliably observed in these assays (see the Supporting Information
for more details). For more information on autoinhibitory behavior in
ternary complexes, see: Mack, E. T.; Perez-Castillejos, R.; Suo, Z.;
Whitesides, G. M. Anal. Chem. 2008, 80, 5550–5555, and references
contained therein.
Acknowledgment. The authors thank Jacob Appelbaum and
Phillip Lichtor for helpful suggestions, Caitlin Sengelaub for
technical assistance, and Professor Guido Ferrari (Duke Uni-
versity) for helpful discussions. This work was funded by the
National Institutes of Health through the NIH Director’s New
Innovator Award Program (Grant DP22OD002913 to D.A.S.).
K.S.A. acknowledges NIH Grant GM49551 for funding support.
The following reagents were obtained through the AIDS
Research and Reference Reagent Program, Division of AIDS,
NIAID, NIH: CHO-WT (here called CHO-gp120) from Dr. Carol
Weiss and Dr. Judith White and MT-2 cells, catalog no. 237,
from Douglas Richman.
(20) More details regarding assay conditions and troubleshooting can be found
in the Supporting Information.
(21) Carlson, C.; Mowery, P.; Owen, R.; Dykhuizen, E. C.; Kiessling, L. ACS
Chem. Biol. 2007, 2, 119–127.
(22) Owen, R.; Carlson, C.; Xu, J.; Mowery, P.; Fasella, E.; Kiessling, L.
ChemBioChem 2007, 8, 68–82.
(23) Popkov, M.; Gonzalez, B.; Sinha, S.; Barbas, C. Proc. Natl. Acad. Sci.
U.S.A. 2009, 106, 4378–4383.
(24) Popkov, M.; Rader, C.; Gonzalez, B.; Sinha, S.; Barbas, C. Int. J. Cancer
2006, 119, 1194–1207.
Supporting Information Available: Detailed experimental pro-
cedures, compound characterization, and complete author lists for
refs 6 and 11. This material is available free of charge via the Internet
(25) Low, P.; Henne, W.; Doorneweerd, D. Acc. Chem. Res. 2008, 41, 120–
129.
(26) Lu, Y.; You, F.; Vlahov, I.; Westrick, E.; Fan, M.; Low, P. S.; Leamon,
C. P. Mol. Pharm. 2007, 4, 695–706.
(27) Rader, C.; Sinha, S. C.; Popkov, M.; Lerner, R. A.; Barbas, C. F. Proc.
Natl. Acad. Sci. U.S.A. 2003, 100, 5396–5400.
(28) Bertozzi, C. R.; Bednarski, M. D. J. Am. Chem. Soc. 1992, 114, 5543–
5546.
References
(29) Bertozzi, C. R.; Bednarski, M. D. J. Am. Chem. Soc. 1992, 114, 2242–
2245.
(1) Brekke, O. H.; Sandlie, I. Nat. ReV. Drug DiscoVery 2003, 2, 52–62.
(2) Allen, T. M. Nat. ReV. Cancer 2002, 2, 750–763.
(30) Li, J.; Zacharek, S.; Chen, X.; Wang, J. Q.; Zhang, W.; Janczuk, A.; Wang,
P. G. Bioorg. Med. Chem. 1999, 7, 1549–1558.
(3) Corson, T. W.; Aberle, N.; Crews, C. M. ACS Chem. Biol. 2008, 3, 677–
(31) Krishnamurthy, V. M.; Quinton, L. J.; Estroff, L. A.; Metallo, S. J.; Isaacs,
J. M.; Mizgerd, J. P.; Whitesides, G. M. Biomaterials 2006, 27, 3663–
3674.
692.
(4) Antibodies recognizing the DNP epitope have been estimated to constitute
1% of circulating IgM and 0.8% of circulating IgG. See: (a) Karjalainen,
K.; Makela, O. Eur. J. Immunol. 1976, 6, 88–93. (b) Farah, F. S.
Immunology 1973, 25, 217–226. The prevalence of anti-DNP antibodies
has been estimated at between 18 and 90% of humans. See: (c) Ortega,
E.; Kostovetzky, M.; Larralde, C. Mol. Immunol. 1984, 21, 883–888. (d)
Jormalainen, S.; Makela, O. Eur. J. Immunol. 1971, 1, 471–478.
(5) Miranda, L. R.; Schaefer, B. C.; Kupfer, A.; Hu, Z. X.; Franzusoff, A.
Proc. Natl. Acad. Sci. U.S.A. 2002, 99, 8031–8036.
(32) Shokat, K. M.; Schultz, P. G. J. Am. Chem. Soc. 1991, 113, 1861–1862.
(33) Naicker, K. P.; Li, H.; Heredia, A.; Song, H.; Wang, L. Org. Biomol. Chem.
2004, 2, 660–664.
(34) Perdomo, M. F.; Levi, M.; Ilberg, M. S.; Vahlne, A. Proc. Natl. Acad. Sci.
U.S.A. 2008, 105, 6.
(35) Rawool, D. B.; Bitsaktsis, C.; Li, Y.; Gosselin, D. R.; Lin, Y.; Kurkure,
N. V.; Metzger, D. W.; Gosselin, E. J. J. Immunol. 2008, 180, 5548–5557.
(6) Wang, T.; et al. J. Med. Chem. 2003, 46, 4236–4239.
JA9057647
9
16394 J. AM. CHEM. SOC. VOL. 131, NO. 45, 2009