Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Peptide containing doai
Reexamination Certificate
1999-04-02
2004-11-09
Seidel, Marianne C. (Department: 1614)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Peptide containing doai
C530S327000, C435S007100
Reexamination Certificate
active
06815423
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to peptide-based compounds having light-emitting moieties. Peptides may be chemically linked with detectable “labels” and used, for example, to monitor peptide, cytokine, drug, and hormone receptors at the cellular level. Typically, the labeled peptide is placed in contact with a tissue or cell culture where it binds to an available receptor. Once bound, the label is detected, allowing properties such as receptor distribution or receptor binding kinetics to be monitored.
Peptides are typically labeled with radioactive elements such as
125
I or
3
H. In this case, emission of high-energy radioactive particles is monitored using standard &ggr;-ray detectors, thereby allowing detection of the label. While detection techniques for
125
I and
3
H are well-known, radioactive compounds by nature have limited half lives, and are often both toxic and expensive. Moreover, current detection technology makes it difficult or impossible to detect radioactive probes in real-time, thereby precluding study of kinetic processes.
Substance P is a particularly desirable peptide to label and use to monitor cell receptors, as this compound exhibits multiple biological roles including stimulation of visceral smooth muscle in the intestine and uterus. Substance P is an eleven amino acid peptide, first isolated in the brain and intestine, and has been identified as a major afferent neurotransmitter in pain transmission in the spinal chord (Kuraishi et al,
Neuroscience
30:241 (1989)). Substance P is responsible for the release of endogenous substances, including the release of histimine from mast cells (Regoli et al.
Pharmacological Reviews
46(4):551 (1994)).
SUMMARY OF THE INVENTION
The present invention provides a compound containing a substance P peptide and a light-emitting moiety that is both biologically active and optically detectable. The peptide is chemically attached to the light-emitting moiety at an amino acid position that is not involved in binding to the peptide receptor. In this way, the peptide's affinity for the binding site is not significantly decreased, and the compound retains high biological activity and can be easily detected using standard optical means.
In general, in one aspect, the invention provides a biologically active compound of the formula:
where R
1
is a light-emitting moiety and R
2
is a substance P-based peptide and fragment, derivative or analog thereof. The peptide is linked at a first amino acid position to (C—X) which, in turn, is selected from the group including C═O, C═S, CH(OH), C═C═O, C═NH, CH
2
, CH(OR), CH(NR), CH(R), CR
3
R
4
, and C(OR
3
)OR
4
where R, R
3
, and R
4
are alkyl moieties or substituted alkyl moieties. Preferably, the compound exhibits substantial biological activity in the presence of receptors having affinities for substance P-based peptides. The compound may also be in the form of a pharmaceutically acceptable salt or complex thereof. Preferably, the first amino acid position bound to (C—X) is included in the N-terminus amino acid of the substance P-based peptide.
In other preferred embodiments, the substance P-based peptide includes the amino acid sequence Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met (SEQ ID NO:1) and the Arg-residue is attached to the (C—X) moiety. The arginine residue preferably is chemically bound to the (C—X) moiety through the N-terminus amine group. In still other preferred embodiments, the (C—X) bond is either C═O or C═S. In another preferred embodiment, the peptide may be amidated at the C-terminus.
In other preferred embodiments, the light-emitting moiety (R
1
) is selected from the group including 4,4-difluoro-4-bora-3a-diaza-s-indacene, fluorescein, FTC, Texas red, phycoerythrin, rhodamine, carboxytetramethylrhodamine, 4′6-diamidino-2-phenylindole (DAPI), indopyras dyes, Cascade blue, coumarins, nitrobenzo-2-oxa-diazole (NBD), Lucifer Yellow, propidium iodide, CY3, CY5, CY9, dinitrophenol (DNP), lanthanide cryptates, lanthanide chelates, non-fluorescent dialdehydes (OPA, NDA, ADA, ATTOTAG reagents from Molecular Probes) which react with primary amines (N-term lys) in the presence of a nucleophile (i.e. CN
−
) to form fluorescent isoindoles, dansyl dyes fluorescamine and dabcyl chloride, 5-((((2-iodoacetyl)amino)ethyl)amino)naphthalene-1-sulfonic acid, long lifetime dyes comprised of metal-ligand complexes (MLC) which consist of a metal center (Ru, Re, Os) and organic or inorganic ligands complexed to the metal such as [Ru(bpy)3]
2+
and [Ru(bpy)
2
(dcbpy)], and the like and derivatives thereof. The light-emitting moiety can be attached to the peptide by reaction of a reactive side group (of the light-emitting moiety) with the N-terminus amino acid of substance P. Suitable linking moieties include, by way of example only, indoacetamide, maleimide, isothiocyanate, succinimidyl ester, sulfonyl halide, aldehydes, glyoxal, hydrazine and derivatives thereof.
By “substance P-based compound” is meant a peptide which includes substance P, fragments of substance P, derivatives or analogs thereof. Substance P-based peptides may be peptides whose sequences differ from substance P's wild-type sequence by only conservative amino acid substitutions. For example, one amino acid may be substituted for another with similar characteristics (e.g., valine for glycine, arginine for lysine, etc.) or by one or more non-conservative amino acid substitutions, deletions, or insertions which do not abolish the peptide's biological activity. Other useful modifications include those which increase substance P's stability. The peptide may contain, for example, one or more non-peptide bonds (which replace a corresponding peptide bond) or D-amino acids in the peptide sequence. Additionally, the C-terminus carboxylic acid group may be modified to increase peptide stability. For example, as described above, the C-terminus may be amidated or otherwise derivatized to reduce the peptide susceptibility to degradation.
In all cases, by “substantially biologically active” is meant the compound binds to a receptor having an affinity IC50 value for the compound which is no more than 15 times, more preferably no more than 10 times and most preferably equal to or less than that of the corresponding unlabeled peptide. Receptor affinity in this case can be determined using known methods, such as methods involving competitive binding of radioactively labeled peptides or by using known methods of fluorescence polarization or other known fluorescence technique for measuring the K
d
for the receptor/peptide interaction.
By “low” or “no” biological activity or “biologically inactive” is meant biological activities less than 1.0% of the biological activity of R
2
—H in the presence of a receptor having affinity for substance P.
The above-identified compound is useful in the labeling of cell receptor sites, cell sorting, flow cytometry and performing fluoroimmunoassays. In another aspect, the invention provides a method for labeling a receptor having an affinity for a substance P-based peptide by contacting the receptor with one or more of the compounds described above. Cell receptor sites, can be imaged by contacting candidate cell receptor sites with the compound of the invention, and then detecting the bound compounds as an indication of the cell receptor sites. Cell sorting can be performed by contacting a population of cells with compound and isolating cells bound to the compound. Flow cytometry can be performed by contacting a population of cells with the compound and detecting cells bearing receptors on their surfaces by detecting cells bound to the compound.
The invention has many advantages. In a general sense, peptide-containing compounds which retain their biological activity after being labeled with light-emitting moieties have a wide variety of biological applications. Such compounds can be used to identify, visualize, quantify, target and select receptors on cells and tissues both in vitro and in
Beaudet Alain
Desjardins Clarissa
Slon-Usakievicz Jacek
Delacroix-Muirheid C.
Iandiorio & Teska
PerkinElmer LAS, Inc.
Seidel Marianne C.
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