Brief Articles
J ournal of Medicinal Chemistry, 1999, Vol. 42, No. 19 4013
with improved stability and bioavailability. These stud-
ies support the proposal that an initial lead compound
with poor pharmacokinetics can be developed with
improved absorption profiles, improved biological half-
life, and improved resistance to degradation and could
still effectively and selectively kill cancer cells.
Refer en ces
(
1) Setyono-Han, B.; Henkelman, M. S.; Foekens, J . A.; Klijn, J . G.
M. Direct inhibitory effects of somatostatin (analogues) on the
growth of human breast cancer cells. Cancer Res. 1987, 47,
1
566-1570.
(
2) Schally, A. V. Oncological applications of somatostatin analogues.
Cancer Res. 1988, 48, 6977-6985.
3) Bogden, A. E.; Taylor, J . E.; Moreau, J .-P.; Coy, D. H.; LePage,
D. J . Response of human lung tumor xenografts to treatment
with a somatostatin analogue (Somatuline). Cancer Res., 1990,
50, 4360-4365.
(
Exp er im en ta l Section
Synthesis, purification, and characterization of the peptides
8
were carried out as previously described. Mass spectra were
(4) K e` ri, Gy.; EÄ rchegyi, J .; Horv a` th, A.; Mez o¨ , I.; Idei, M.; V a` ntus,
T.; Balogh, AÄ .; Vad a` sz, Zs.; B o¨ k o¨ nyi, Gy.; Sepr o¨ di, J .; Tepl a` n, I.;
Csuka, O.; Tejeda, M.; Ga a` l, D.; Szegedi, Zs.; Szende, B.; Roze,
C.; Kalthoff, H.; Ullrich, A. A tumor-selective somatostatin
analogue (TT-232) with strong in vitro and in vivo antitumor
activity. Proc. Natl. Acad. Sci. U.S.A. 1996, 93, 12513-12518.
run on a Fisons VG-TOF spectrometer using matrix-assisted
laser desorption ionization (MALDI) or a VG Analytical ZAB-
SE instrument, using fast atom bombardment (FAB) ioniza-
tion, or a Finnigan MassLab Navigator quadrupole mass
2
spectrometer, using electrospray ionization. N flow, 300 L/h;
(5) Wang, W. Review, Oral protein drug delivery. J . Drug Target.
temperature, 180 °C; cone voltage; 49 V. The spectral data and
the details for the synthesis of 1,2,3,4,6-penta-O-acetyl-R,â-D-
glucopyranose (3), 2,3,4,6-tetra-O-acetyl-â-D-glucopyranosyl
azide (4), 2,3,4,6-tetra-O-acetyl-â-D-glucopyranosylamine (5)
and N-(2,3,4,6-tetra-O-acetyl-â-D-glucopyranosyl)succinamide
1996, 4, 195-232.
(6) Toth, I. Review: A novel chemical approach to drug delivery:
Lipidic amino acids conjugates. J . Drug Target. 1994, 2, 217-
2
39.
(
(
(
7) Toth, I.; Christodoulou, M.; Bankowsky, K.; Flinn, N.; Gibbons,
W. A.; Godeau, G.; Moczar, E.; Hornebeck, W. Design of potent
lipidic-peptide inhibitors of human neutrophil elastase. In vitro
and in vivo studies. Int. J . Pharm. 1995, 125, 117-122.
8) Kellam, B.; Drouillat, B.; Dekany, G.; Starr, M. S.; Toth, I.
Synthesis and in vitro evaluation of lipoamino acid and carbo-
hydrate modified enkephalins as potential antinociceptive agents.
Int. J . Pharm. 1998, 161, 55-64.
9) Horv a´ th, A.; Vad a` sz, Zs.; Csuka, O.; VanBinst, G.; J aspers, H.;
Idei, I.; EÄ rchegyi, J .; Sepr o¨ di, J .; Horv a` th, J .; Mez o¨ , I.; Tep a´ ln,
I.; K e´ ri, Gy. Somatostatin octa- and heptapeptides, structural
and biological characteristics. Peptides 1996, 483-484.
(6) are provided as Supporting Information.
In Vitr o An tip r olifer a tive Effect of Con ju ga tes on
Hu m a n Tu m or Cell Lin es. The conjugates (1b-1o) and
control TT-232 (1a ) were incubated with various tumor cell
lines for 24 and 48 h, at varying concentrations (20, 50, 100
µg/mL). Visualization of the antitumor activity was achieved
by employing a spectrophotometric assay using a tetrazolium
1
5
salt (MTT), which was converted to a colored derivative
Formazan) only by surviving cells and not those killed by the
(
analogues. The OD of the Formazan produced was measured
at 570 nm. The tumor cell lines used were SW620 (colonic),
PC3 (prostatic), HT29 (colonic), A2058 (melanoma), and A431
(
10) de J ong, M.; Bakker, W. H.; Krenning, E. P.; Breeman, W. A.
P.; van der Pluijm, M. E.; Bernard, B. F.; Visser, T. J .; J ermann,
E.; B e´ h e´ , M.; Powell, P.; M a¨ cke, H. R. Yttrium-90 and Indium-
0
(epidermoid carcinoma) cells.
111 labeling, receptor binding and biodistribution of [DOTA ,D-
1
3
Phe ,Tyr ]octreotide, a promising somatostatin analogue for
radionuclide therapy. Eur. J . Nucl. Med. 1997, 24, 368-370.
11) Nomoto, M.; Yamada, K.; Haga, M.; Hayashi, M. Improvement
of intestinal absorption of peptide drugs by glycosylation:
Transport of a tetrapeptide by the sodium independent D-glucose
transporter. J . Pharm. Sci. 1998, 87, 326-332.
In testin a l Ep ith elia l Absor p tion of P ep tid es 1f, 1g, 1k ,
a n d 1l. Absorption studies were performed using differenti-
ated human intestinal epithelial cell monolayers cultivated in
permeable cell culture inserts. The experimental details on the
cell culture, the determination of the integrity of Caco-2 cell
monolayers after exposure to peptides and transepithelial
electrical resistance, and the examination of the transport of
(
(12) Fukuda, M. Carbohydrate-Dependent Cell Adhesion. Bioorg.
Med. Chem. 1995, 3, 207-215.
(13) Toth, I.; Hillery, A. M.; Wood, I.; Magnusson, C.; Artursson, P.
Oral absorption of lipoamino acid conjugates. Int. J . Pharm.
3
H-labeled peptides 1f, 1g, 1k , and 1l across Caco-2 cell
monolayers where carried out as previously described.1
6-18
The
1
994, 102, 223-230.
experimental details are given in the Supporting Information
and are available in the World Wide Web edition of this
J ournal.
St a t ist ics. Results are expressed as mean values ( SD.
Statistical differences between two mean values were evalu-
ated by unpaired two-tailed t-test.
(
14) Artursson, P.; Karlsson, J . Correlation between oral drug
absorption in humans and apparent drug permeability coef-
ficients in human intestinal epithelial (Caco-2) cells. Biochem.
Biophys. Res. Commun. 1991, 175, 880-885.
(15) Hansen, M. B.; Nielsen, S. E.; Berg, K. Reexamination and
further development of a precise and rapid dye method for
measuring cell growth/cell kill. J . Immunol. Methods 1989, 119,
2
03-210.
Ack n ow led gm en t. This work was supported in part
by a grant from the British Council (No. GB-43/95), the
Hungarian National Research Foundation (OTKA
T026385 and OTKA T026388), and Inco-Coppernicus
European Grant (PL 966087).
(
16) Artursson, P.; Karlsson, J .; Ocklind, G.; Schipper, N. Models of
absorptive epithelia for studying transport processes. In Cell
Models of Epithelial Tissues - A Practical Approach; Shaw, A.,
Ed.; IRL: Oxford, 1996; pp 111-133.
17) Anderberg, E. K.; Nystr o¨ m, C.; Artursson, P. Epithelial transport
of drugs in cell culture. VII: Effects of pharmaceutical surfactant
exipients and bile acids on transepithelial permeability in
monolayers of human intestinal epithelial (Caco-2) cells. J .
Pharm. Sci. 1992, 81, 879-887.
(18) Artursson, P.; Magnusson, C. Epithelial transport of drugs in
cell culture. II: Effect of extracellular calcium concentration on
the paracellular transport of drugs of different lipophilicities
across monolayers of intestinal epithelial (Caco-2) cells. J .
Pharm. Sci. 1990, 79, 595-600.
(
Su p p or tin g In for m a tion Ava ila ble: Synthesis, purifica-
tion, and characterization of the peptides and compounds 3-6,
in vitro antiproliferative effect of conjugates on human tumor
cell lines, intestinal epithelial absorption of peptides, HPLC
retention time of compounds 1a -1o, MS data of compounds
1
a -1o, and microanalysis of compounds 3-6. This informa-
tion is available free of charge via the Internet at http://
pubs.acs.org.
J M9910167