Patent Application
20240361330
The present invention relates to a method of relativizing signals by using a neoglycoprotein as a standard for glycoproteins, wherein said neoglycoprotein comprises a streptavidin molecule bound through biotin to at least one, preferably four, pre-defined glycan determinant(s) which comprises said glycan structure (A) and a corresponding use of said neoglycoprotein. Thereby, statements whether a particular glycan structure (A) is present on a protein of interest are possible. Applications in diagnosis of diseases such as cancer, autoimmune disease or inflammatory disease are disclosed.
Glycans are present on a variety of different proteins, where they have an impact on protein trafficking, stability and folding, ultimately altering its biochemical, and biophysical properties. Moreover, glycans can mediate proteolysis patterns or directly mediate ligand-receptor interactions, oncogenic signaling transduction, immune recognition, migration and both cell-cell and cell-matrix adhesion. As such, particular glycans may exert a selective advantage for tumor cells. The presence of particular glycans or the presence of particular glycans on particular proteins thus may be used as a biomarker, e.g., for the diagnosis of cancer.
Glycan structures can be analyzed by using binding molecules that specifically bind to a particular glycan structure. Besides antibodies specific for glycan structures also lectins can be employed. Lectins are carbohydrate-binding proteins that are highly specific for sugar groups that are part of other molecules. These binding molecules can be used in assays like enzyme-linked immunosorbent assay (ELISA), enzyme-linked lectin assay (ELLA), magnetic ELLA (MELLA) to analyze the presence or absence of a particular glycan structure.
The signals obtained by applying these methods however needs to be relativized by a (positive) control or standard to allow valid statements whether there is said particular glycan structure present or not or to quantify it in a sample. Commercially available glycoprotein standards contain only one glycan structure, which is not identical to the glycan structure of interest, i.e. these cannot be used for assessing whether a glycan structure relevant for a disease is present on the protein of interest or not. Thus, protein standards comprising a particular glycan structure are not easily available. One possibility to obtain such controls is to conjugate the glycan structure of interest to the protein of interest. However, this is complicated, labor-intensive and expensive. Furthermore, it has to be repeated for every new combination of glycan structure of interest and protein of interest.
Consequently, there is an ongoing need for reliable, inexpensive and versatile glycoprotein standards. The present invention aims to address this need.
This need is solved by the subject-matter as defined in the claims and in the embodiments described herein.
The Inventors surprisingly found that it is not necessary to provide such a modified (glyco)protein of interest to relativize a signal obtained from determining a signal (1) obtained from determining a glycan structure (A) suspected to be present on a protein of interest but instead a neoglycoprotein can be used as a standard. This standard provides the signal (2) obtained from determining said glycan structure (A) actually comprised by a neoglycoprotein. The neoglycoprotein comprises a streptavidin molecule bound through biotin to at least one pre-defined glycan determinant which comprises said glycan structure (A). Thus, streptavidin can be seen as the scaffold for a neoglycoprotein, which itself acts as a standard for relativizing. As shown in the Examples, streptavidin loaded with biotinylated glycan structures (A) can be used as a standard.
Accordingly, the present invention relates to a method for relativizing a signal (1) obtained from determining a glycan structure (A) suspected to be present on a protein of interest, comprising comparing the signal obtained from determining said glycan structure (A) suspected to be present on said protein of interest with the signal (2) obtained from determining said glycan structure (A) actually comprised by a neoglycoprotein, wherein said neoglycoprotein comprises a streptavidin molecule bound through biotin to at least one pre-defined glycan determinant which comprises said glycan structure (A), thereby relativizing said signal (1) to said signal (2), or vice versa.
Also, the present invention relates to a method for relativizing a signal (1) obtained from determining a glycan structure (A) suspected to be present on a protein of interest, comprising comparing the signal obtained from determining said glycan structure (A) suspected to be present on said protein of interest with the signal (2) obtained from determining said glycan structure (A) actually comprised by a neoglycoprotein acting as a standard, wherein said neoglycoprotein comprises a streptavidin molecule bound through biotin-streptavidin interaction to at least one pre-defined glycan determinant which comprises said glycan structure (A), wherein relativizing comprises comparing signal (1) with signal (2) from the standard, thereby signal (2) allows putting the information obtained by signal (1) in relation, thereby relativizing said signal (1) to said signal (2), or vice versa.
The present invention further relates to the use of a neoglycoprotein comprising a streptavidin molecule bound through biotin to at least one pre-defined glycan determinant which actually comprises a glycan structure (A) suspected to be present on a protein of interest for relativizing a signal (1) obtained from determining glycan structure (A) suspected to be present on a protein of interest to a signal (2) obtained from determining said glycan structure (A) actually comprised by said neoglycoprotein, wherein said neoglycoprotein comprises a streptavidin molecule bound through a streptavidin-binding molecule to at least one pre-defined glycan determinant which comprises said glycan structure (A).
Also, the present invention relates to the use of a neoglycoprotein acting as a standard comprising a streptavidin molecule bound through biotin to at least one pre-defined glycan determinant which actually comprises a glycan structure (A) suspected to be present on a protein of interest for relativizing a signal (1) obtained from determining glycan structure (A) suspected to be present on a protein of interest to a signal (2) obtained from determining said glycan structure (A) actually comprised by said neoglycoprotein, wherein said neoglycoprotein comprises a streptavidin molecule bound through biotin-streptavidin interaction to at least one pre-defined glycan determinant which comprises said glycan structure (A) wherein relativizing comprises comparing signal (1) with signal (2) from the standard, thereby signal (2) allows putting the information obtained by signal (1) in relation.
Relativizing may comprise comparing signal (1) with signal (2) from the standard, thereby signal (2) allows putting the information obtained by signal (1) in relation. Advantageously, with such a comparison, signal (1) is relativized to said signal (2), or vice versa.
Relativizing may comprise comparing the signal obtained from determining said glycan structure (A) suspected to be present on said protein of interest with a signal (2) obtained from determining said glycan structure (A) actually comprised by said neoglycoprotein, (i) wherein, if signal (1) is lower than signal (2), it is indicative that said suspected glycan structure (A) is not present on said protein of interest, or (ii) wherein, if signal (1) is equal to or higher than signal (2), it is indicative that said suspected glycan structure (A) is present on said protein of interest.
Relativizing may further comprise comparing the signal (1) obtained from determining said glycan structure (A) suspected to be present on said protein of interest with the signal (2) obtained from determining a concentration series of said glycan structure (A) actually comprised by said neoglycoprotein.
The concentration series may comprise a concentration which corresponds to a predetermined threshold concentration above which said glycan structure (A) is known to be present on said protein of interest.
The signal may be signal intensity.
The signal (1) and the signal (2) may be obtained by enzyme-linked immunosorbent assay (ELISA), enzyme-linked lectin assay (ELLA), magnetic ELLA (MELLA), preferably ELLA or MELLA.
The glycan structure (A) may be selected from the group consisting of core fucose, antennary fucose, Fucα1-6GlcNAc-N-Asn containing N-linked oligosaccharides, Fucα1-6/3GlcNAc, α-L-Fuc, Fucα1-2Galβ1-4(Fucα1-3)GlcNAc, Fucα1-2Gal, Fucα1-6GlcNAc, Manβ1-4GlcNAcβ1-4GlcNAc, branched N-linked hexa-saccharide, Manα1-3Man, α-D-Man, (GlcNAcβ1-4)2-4, Galβ1-4GlcNAc, GlcNAcα1-4Galβ1-4GlcNAc, (GlcNAcβ1-4)2-5, Neu5Ac (sialic acid), Galβ1-3GalNAc-serine/threonine, Galα1-3GalNAc, Galβ1-6Gal, Galβ1-4GlcNAc, Galβ1-3GalNAc, GalNAcα1-3GalNAc, GalNAcα1-3Gal, GalNAcα/β1-3/4Gal, α-GalNAc, GalNAcβ1-4Gal, GalNAcα1-3(Fucα1-2)Gal, GalNAcα1-2Gal, GalNAcα1-3GalNAc, GalNAcβ1-3/4Gal, GalNAc-Ser/Thr (Tn antigen), Galβ1-3GalNAc-Ser/Thr (T antigen), GalNAcβ1-4GlcNAc (LacdiNAc), α-2,3Neu5Ac (α2-3 linked sialic acid), α-2,6Neu5Ac (α2-6 linked sialic acid), α-2,8Neu5Ac (α2-8 linked sialic acid), sialic acid (α-2,3Neu5Ac, α-2,6Neu5Ac or α-2,8Neu5Ac), Neu5Acα4/9-O-Ac-Neu5Ac, Neu5Acα2-3Galβ1-4Glc/GlcNAc, Neu5Acα2-6Gal/GalNAc, N-linked bi-antennary, N-linked tri/tetra-antennary, branched β1-6GlcNAc, Galα1-3(Fucα1-2)Galβ1-3/4GlcNAc, Galβ1-3(Fucα1-4)GlcNAc, NeuAcα2-3Galβ1-3(Fucα1-4)GlcNAc, Fucα1-2Galβ1-3(Fucα1-4)GlcNAc, Galβ1-4(Fucα1-3)GlcNAc, NeuAcα2-3Galβ1-4(Fucα1-3)GlcNAc, Fucα1-2Galβ1-4(Fucα1-3)GlcNAc, high mannose, sialyl Lewisa (sialyl Lea) antigen, sialyl Lewisx(sialyl Lex) antigen, Lewisx (Lex) antigen, sialyl Tn antigen, sialyl T antigen, Lewisy (Ley) antigen, sulfated core1 glycan, Tn antigen, T antigen, core 2 glycan, Lewisa (Lea) antigen, (GlcNAcβ1-4)n, β-D-GlcNAc, GalNAc, Gal-GlcNAc, GlcNAc, Galα1-3Gal, Galβ1-3GalNAc, α-Gal, α-GalNAc, (GlcNAc)n, branched (LacNAc)n.
The protein of interest may be a cancer biomarker protein, an autoimmune disease biomarker protein or an inflammatory disease biomarker protein. Said cancer biomarker protein may be an ovarian cancer biomarker protein, breast cancer biomarker protein, colorectal cancer biomarker protein, pancreatic cancer biomarker protein, prostate cancer biomarker protein, thyroid cancer biomarker protein, liver cancer biomarker protein, lung cancer biomarker protein, stomach cancer biomarker protein, testicular cancer biomarker protein or bladder cancer biomarker protein. Said prostate cancer biomarker protein may be β-haptoglobin, TIMP-1, PSA, fPSA or tPSA.
The presence of said glycan structure (A) may be indicative of cancer.
The invention will be better understood with reference to the detailed description when considered in conjunction with the non-limiting examples and the accompanying drawings, in which:
The present invention is described in detail in the following and will also be further illustrated by the appended examples and figures.
If available, the standards used in prior art typically are the proteins of interest, which are labelled with the glycan structure (A) (of interest), which is suspected to be on the protein of interest. The standard in prior art is thus the protein of interest itself, which comprises the glycan structure (A). Synthesizing such standards is however, complicated, time-consuming and expensive. The present invention thus aims at providing a reliable, inexpensive and versatile glycan structure or glycoprotein standard for relativizing signals obtained from determining glycan structures suspected to be present on a protein of interest.
The Inventors surprisingly found that it is not necessary to provide such a modified (glyco)protein of interest to relativize a signal obtained from determining a signal (1) obtained from determining a glycan structure (A) suspected to be present on a protein of interest but instead a neoglycoprotein can be used as a standard. This signal (2) obtained from determining a glycan structure (A) on the neoglycoprotein allows the relativization of signal (1). The neoglycoprotein comprises a streptavidin molecule bound through biotin to at least one pre-defined glycan determinant which comprises said glycan structure (A). Thus, streptavidin can be seen as the scaffold for a neoglycoprotein, to which the glycan structure (A) of interest can be coupled.
As shown in the Examples, streptavidin loaded with biotinylated glycan structures (A) can be used as a standard. This is the first study to develop a glycoconjugate or an exemplary neoglycoprotein as described herein consisting of a streptavidin molecule bound to up to four biotinyl-glycans to form a neoglycoprotein with 4 glycans on the protein/streptavidin scaffold. At the same time the inventive concept allows preparing any kind of neoglycoprotein with a defined glycan structure (A) present on the surface of streptavidin using biotinylated glycans. Such a neoglycoprotein with (up to) 4 glycans may then be used as a protein standard for determining said glycan structure (A), e.g. with the MELLA technology disclosed in WO 2019/185515 A1. In an exemplary embodiment, such neoglycoproteins are able to bind to a lectin and an anti-streptavidin antibody at the same time, i.e. in a sandwich configuration to provide an optical signal, which is considered to be the signal to which signal from analysing samples can be relativized using Glycanostics's MELLA protocol for prostate cancer (among others) diagnostics (
Accordingly, the present invention relates to a method for relativizing a signal (1) obtained from determining a glycan structure (A) suspected to be present on a protein of interest, comprising comparing the signal obtained from determining said glycan structure (A) suspected to be present on said protein of interest with the signal (2) obtained from determining said glycan structure (A) actually comprised by a neoglycoprotein, wherein said neoglycoprotein comprises a streptavidin molecule bound through biotin to at least one pre-defined glycan determinant which comprises said glycan structure (A), thereby relativizing said signal (1) to said signal (2), or vice versa.
Also, the present invention relates to a method for relativizing a signal (1) obtained from determining a glycan structure (A) suspected to be present on a protein of interest, comprising comparing the signal obtained from determining said glycan structure (A) suspected to be present on said protein of interest with the signal (2) obtained from determining said glycan structure (A) actually comprised by a neoglycoprotein acting as a standard, wherein said neoglycoprotein comprises a streptavidin molecule bound through biotin-streptavidin interaction to at least one pre-defined glycan determinant which comprises said glycan structure (A), wherein relativizing comprises comparing signal (1) with signal (2) from the standard, thereby signal (2) allows putting the information obtained by signal (1) in relation, thereby relativizing said signal (1) to said signal (2), or vice versa.
The present invention further relates to the use of a neoglycoprotein comprising a streptavidin molecule bound through biotin to at least one pre-defined glycan determinant which actually comprises a glycan structure (A) suspected to be present on a protein of interest for relativizing a signal (1) obtained from determining glycan structure (A) suspected to be present on a protein of interest to a signal (2) obtained from determining said glycan structure (A) actually comprised by said neoglycoprotein, wherein said neoglycoprotein comprises a streptavidin molecule bound through a streptavidin-binding molecule to at least one pre-defined glycan determinant which comprises said glycan structure (A).
Also, the present invention relates to the use of a neoglycoprotein acting as a standard comprising a streptavidin molecule bound through biotin to at least one pre-defined glycan determinant which actually comprises a glycan structure (A) suspected to be present on a protein of interest for relativizing a signal (1) obtained from determining glycan structure (A) suspected to be present on a protein of interest to a signal (2) obtained from determining said glycan structure (A) actually comprised by said neoglycoprotein, wherein said neoglycoprotein comprises a streptavidin molecule bound through biotin-streptavidin interaction to at least one pre-defined glycan determinant which comprises said glycan structure (A) wherein relativizing comprises comparing signal (1) with signal (2) from the standard, thereby signal (2) allows putting the information obtained by signal (1) in relation
“Relativizing” can be seen as describing the process of comparing one signal (1) with another signal (2), thereby providing information on how signal (1) relates to signal (2). Signal (2) can be seen as the standard in the context of the invention. In other words, signal (2) allows putting the information obtained by signal (1), e.g., the signal intensity, in context or relation. Thus, signal (2) may act as a positive control, thereby providing information on the signal that is needed to consider signal (1) as positive. Alternatively or additionally, signal (2) may not only be a positive control but also be the result of a concentration series, thereby allowing the quantification of the amount of the glycan structure (A) by comparing (relativizing) signal (1) to a series of signals (2) at different concentrations. In this context, the methods and uses of the invention can be also described as glycoprofiling the protein of interest.
In line with the above, “relativizing” may comprise comparing signal (1) with signal (2) from the standard, thereby signal (2) allows putting the information obtained by signal (1) in relation. Advantageously, with such a comparison, signal (1) is relativized to said signal (2), or vice versa.
The term “glycoprofile of a protein” means a carbohydrate structure of the protein of interest, e.g., composition and/or structure of covalently linked carbohydrates, e.g., quantity, presence, or absence of covalently linked carbohydrates. The term “glycoprofiling” means determining a carbohydrate structure (e.g., composition and/or structure of covalently linked carbohydrates, e.g., quantity, presence, or absence of covalently linked carbohydrates) on a protein of interest.
The information provided by signal (1) and signal (2) can provide the information whether the glycan structure (A) is present on the protein of interest or not. For this purpose signal (1) (obtained from determining said glycan structure (A) suspected to be present on said protein of interest) is compared (relativized) with the standard/signal (2) (obtained from determining said glycan structure (A) actually comprised by said neoglycoprotein). In case signal (1) is equal or higher than signal (2), it is indicative that said glycan structure (A) is considered to be present on the protein of interest. Accordingly, relativizing may comprise comparing the signal (1) obtained from determining said glycan structure (A) suspected to be present on said protein of interest with a signal (2) obtained from determining said glycan structure (A) actually comprised by said neoglycoprotein, wherein, if signal (1) is lower than signal (2), it is indicative that said suspected glycan structure (A) is not present on said protein of interest.
Otherwise, if signal (1) is lower than signal (2), it is indicative that said glycan structure (A) is considered not to be present on the protein of interest. Accordingly, relativizing may comprise comparing the signal (1) obtained from determining said glycan structure (A) suspected to be present on said protein of interest with a signal (2) obtained from determining said glycan structure (A) actually comprised by said neoglycoprotein, wherein, if signal (1) is equal to or higher than signal (2), it is indicative that said suspected glycan structure (A) is present on said protein of interest.
The methods and uses of the present invention however are not limited to qualitative statements. In contrast, if signal (1) is compared to a series of signals (2), which are determined at a series of different concentrations of the neoglycoprotein, allow a quantitative analysis of the amount of glycan structures (A) suspected to be on the protein of interest in a sample.
Accordingly, relativizing (in the methods and uses of the invention) may comprise comparing the signal (1) obtained from determining said glycan structure (A) suspected to be present on said protein of interest with the signal (2) obtained from determining a concentration series of said glycan structure (A) actually comprised by said neoglycoprotein.
A “concentration series” as described herein relates to data set of signals (2) obtained from determining the glycan structure (A) at two or more different concentrations of the neoglycoprotein. The data set may be used to provide or calculate a standard curve, e.g. by linear regression, that allows conclusions from the signal (intensity) (1) to the actual level or amount of the glycan structure (A) in a sample. The concentration series may also allow setting a predetermined threshold that provides for the signal (intensity), at which the glycan structure (A) is deemed to be present on the protein of interest. To put it differently, the concentration series may be used to set the baseline (threshold) for a data point, at which no neoglycoprotein has been added to the sample to be analyzed (in the concentration series). Accordingly, the concentration series may also comprise a concentration which corresponds to a predetermined threshold concentration above which said glycan structure (A) is known to be present on said protein of interest.
A “neoglycoprotein” as used herein relates to a streptavidin molecule, to which at least 1 and up to 4, i.e., 1, 2, 3 or 4, preferably 4, biotinylated glycan structures (A) are non-covalently bound by the biotin-streptavidin interaction. Accordingly, the neoglycoprotein is bound through biotin-streptavidin interaction. Streptavidin thereby acts as scaffold, which can be coupled to the desired glycan structures (A). Thereby, a highly versatile and quickly available neoglycoprotein standard can be provided. Accordingly, the glycan structure (A) is added to the streptavidin preferably in excess, e.g., at a molar ratio of at least 4:1 (glycan structure (A):streptavidin), at least 5:1, at least 7.5:1 or at least 10:1. Preferably, the glycan structure (A) is added to the streptavidin at a molar ratio of between 4.5:1 and 5.5:1, most preferably at a molar ratio of 5:1.
“Streptavidin” is a protein purified from the bacterium Streptomyces avidinii. Streptavidin homo-tetramers have an extraordinarily high affinity for biotin (also known as vitamin B7 or vitamin H). With a dissociation constant (Kd) on the order of around 10−14 mol/L, the binding of biotin to streptavidin is one of the strongest non-covalent interactions known in nature. An exemplary amino acid sequence of a wild type streptavidin is: MRKIVVAAIAVSLTTVSITASASADPSKDSKAQVSAAEAGITGTWYNQLGSTFIVTAGADGALTG TYESAVGNAESRYVLTGRYDSAPATDGSGTALGWTVAWKNNYRNAHSATTWSGQYVGGAEA RINTQWLLTSGTTEANAWKSTLVGHDTFTKVKPSAASIDAAKKAGVNNGNPLDAVQQ (SEQ ID NO: 1). An exemplary wild type sequence of streptavidin is also shown in UniProt database entry P22629, version 1 of 1 Aug. 1991. Streptavidin as used herein, e.g., in the context of the methods or uses described herein, may also encompass streptavidin muteins. Streptavidin muteins are, e.g., disclosed in WO 2017/186669 or WO 2014/076277. Streptavidin or streptavidin muteins used in the methods and uses of the invention may be derived from streptavidin variants which are shortened at the N- or/and the C-terminus. A preferred polypeptide according to the present invention comprises the amino acid sequence of a minimal streptavidin which begins N-terminally in the region of the amino acid positions 10 to 16 and terminates C-terminally in the region of the amino acid positions 133 to 142. Such a streptavidin mutein polypeptide corresponds preferably to a minimal streptavidin outside of the mutation region which comprises an amino acid sequence from position Ala13 to Ser139 and optionally has an N-terminal methionine residue instead of Ala13. In this application the numbering of amino acid positions refers throughout to the numbering of mature wt-streptavidin (Argarana et al., Nucleic Acids Res. 14 (1986), 1871-1882, cf. SEQ ID NO: 1) which is also deposited under accession number UniProtKB-P22629, v1 of 1 Aug. 1991. “Streptavidin” as used here, in the context of the methods or uses described herein, may also relate to other biotin-binding moieties besides streptavidin, e.g. proteins or aptamers binding to biotin.
Streptavidin may have an amino acid sequence that is substantially identical to that of SEQ ID NO: 1. Streptavidin as used herein may have an amino acid sequence having a sequence identity of at least 80%, at least 90%, at least 95%, at least 98%, at least 99% or 100% to of SEQ ID NO: 1. Streptavidin as used herein may consist of an amino acid sequence having a sequence identity of at least 80%, at least 90%, at least 95%, at least 98%, at least 99% or 100% to of SEQ ID NO: 1.
Generally, when used herein, the terms “percent (%) identical” or “percent (%) identity,” in the context of two or more nucleic acids or polypeptide sequences, refers to the extent to which two or more sequences or subsequences that are the same. Two sequences are “identical” if they have the same sequence of amino acids or nucleotides over the region being compared. Two sequences are “substantially identical” if two sequences have a specified percentage of amino acid residues or nucleotides that are the same (i.e., 60% identity, optionally 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% identity over a specified region, or, when not specified, over the entire sequence), when compared and aligned for maximum correspondence over a comparison window, or designated region as measured using one of the following sequence comparison algorithms or by manual alignment and visual inspection. Optionally, the identity exists over a region that is at least about 30 nucleotides (or 10 amino acids) in length, or more preferably over a region that is 100 to 500 or 1000 or more nucleotides (or 20, 50, 200 or more amino acids) in length.
The percentage of sequence homology or sequence identity can, for example, be determined herein using the program BLASTP, version blastp 2.2.5 (Nov. 16, 2002) (cf. Altschul et al., Nucleic Acids Res, 1997). In this embodiment the percentage of homology is based on the alignment of the entire polypeptide sequence (matrix: BLOSUM 62; gap costs: 11.1; cut-off value set to 10−3) including the propeptide sequences, preferably using the wild-type protein scaffold as reference in a pairwise comparison. It is calculated as the percentage of numbers of “positives” (homologous amino acids) indicated as result in the BLASTP program output divided by the total number of amino acids selected by the program for the alignment.
A “glycan” or a “glycan structure (A)” relates to compounds consisting of monosaccharides linked glycosidically and may also refer to carbohydrate portion of a glycoconjugate, such as a glycoprotein, glycolipid, glycoRNA (see, e.g., Flynn et al, Cell, 184(12):3109-3124) or a proteoglycan, even if the carbohydrate is only a monosaccharide or an oligosaccharide.
The glycan structure (A) bound to the streptavidin in the neoglycoprotein described herein is advantageously biotinylated. “Biotinylation” is the process of covalently attaching biotin to a protein, nucleic acid or other molecule, in particular to a glycan structure (A) as described herein. Various methods for biotinylating glycan structures (A) are known to a person skilled in the art. E.g., the biotinylation may be based on reductive amination in which a primary amine is coupled to an aldehyde to form an imine or a hydrazone if the primary amine is present as a hydrazide group. This imine (hydrazone) is then reduced to a secondary amine, which stabilizes the formed linkage (see scheme below). Using this reaction procedure, biotin-LC-hydrazide can be readily coupled to the reducing end of any carbohydrate to form a stable biotin-labeled product. See, e.g., Grün et al. (2006), Analytical Biochemistry, 354(1):54-63, hereby incorporated by reference in its entirety.
The biotin may also be coupled to the glycan by a polyethylene glycol linker such as a triethylene glycol (PEG3) spacer between glycan and biotin. An exemplary glycan structure (A) is 3′-sialyllactosamine-PEG3-biotin (single arm, ˜1100 Da), a biotinylated 3′-Sialylated N-acetyllactosamine (LacNAc=LN=Galβ1,4GlcNAc) with beta-linked triethylene glycol (PEG3) spacer between glycan and biotin. Such biotinylated glycans are commercially available, e.g., from Sussex Chemicals, Ottawa, Canada.
The present invention is not limited to any particular glycan structure (A). In contrast, the modularly construction of the neoglycoprotein allows the non-covalent attachment of virtually any glycan structure (A) to the streptavidin, which is the scaffold of the neoglycoprotein described herein. Exemplary glycan structures (A) include, but are not limited to, core fucose, antennary fucose, Fucα1-6GlcNAc-N-Asn containing N-linked oligosaccharides, Fucα1-6/3GlcNAc, α-L-Fuc, Fucα1-2Galβ1-4(Fucα1-3)GlcNAc, Fucα1-2Gal, Fucα1-6GlcNAc, Manβ1-4GlcNAcβ1-4GlcNAc, branched N-linked hexa-saccharide, Manα1-3Man, α-D-Man, (GlcNAcβ1-4)2-4, Galβ1-4GlcNAc, GlcNAcα1-4Galβ1-4GlcNAc, (GlcNAcβ1-4)2-5, Neu5Ac (sialic acid), Galβ1-3GalNAc-serine/threonine, Galα1-3GalNAc, Galβ1-6Gal, Galβ1-4GlcNAc, Galβ1-3GalNAc, GalNAcα1-3GalNAc, GalNAcα1-3Gal, GalNAcα/β1-3/4Gal, α-GalNAc, GalNAcβ1-4Gal, GalNAcα1-3(Fucα1-2)Gal, GalNAcα1-2Gal, GalNAcα1-3GalNAc, GalNAcβ1-3/4Gal, GalNAc-Ser/Thr (Tn antigen), Galβ1-3GalNAc-Ser/Thr (T antigen), GalNAcβ1-4GlcNAc (LacdiNAc), α-2,3Neu5Ac (α2-3 linked sialic acid), α-2,6Neu5Ac (α2-6 linked sialic acid), α-2,8Neu5Ac (α2-8 linked sialic acid), sialic acid (α-2,3Neu5Ac, α-2,6Neu5Ac or α-2,8Neu5Ac), Neu5Acα4/9-O-Ac-Neu5Ac, Neu5Acα2-3Galβ1-4Glc/GlcNAc, Neu5Acα2-6Gal/GalNAc, N-linked bi-antennary, N-linked tri/tetra-antennary, branched β1-6GlcNAc, Galα1-3(Fucα1-2)Galβ1-3/4GlcNAc, Galβ1-3(Fucα1-4)GlcNAc, NeuAcα2-3Galβ1-3(Fucα1-4)GlcNAc, Fucα1-2Galβ1-3(Fucα1-4)GlcNAc, Galβ1-4(Fucα1-3)GlcNAc, NeuAcα2-3Galβ1-4(Fucα1-3)GlcNAc, Fucα1-2Galβ1-4(Fucα1-3)GlcNAc, high mannose, sialyl Lewisa (sialyl Lea) antigen, sialyl Lewisx (sialyl Lex) antigen, Lewisx (Lex) antigen, sialyl Tn antigen, sialyl T antigen, Lewisy (Ley) antigen, sulfated core1 glycan, Tn antigen, T antigen, core 2 glycan, Lewisa (Lea) antigen, (GlcNAcβ1-4)n, β-D-GlcNAc, GalNAc, Gal-GlcNAc, GlcNAc, Galα1-3Gal, Galβ1-3GalNAc, α-Gal, α-GalNAc, (GlcNAc)n, branched (LacNAc)n.
Carbohydrate abbreviations as used herein include: “Neu5Ac” for N-acetylneuraminic acid; “Fuc” for fucose, “GalNAc” for N-acetylgalactosamine; “GlcNAc” for N-acetylglucosamine; “Gal” for galactose (e.g., Varki A, Cummings R D, Esko J D, Freeze H H, Stanley P, Bertozzi C R, Hart G W, E. M E., Essentials of Glycobiology, 2nd edition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor (NY), 2009).
Furthermore, as used herein the following terms are defined below:
The “signal” as used herein relates to the information obtained by determining a glycan structure (A) (suspected to be) on a protein of interest. This information typically is signal intensity, e.g., of an absorption at a particular wave length or fluorescence emission at a particular wave length. The signal intensity preferably is dependent on the amount of glycan structure (A) present on the protein of interest. The signal may thus also be seen as providing information on the glycoprofile of the protein of interest.
The neoglycoprotein described herein acts as a standard in methods and uses of the invention. These relate to determining a glycan structure (A) providing a signal (1) or a signal (2). “Determining a glycan structure (A)” as used herein relates to any method that is suitable for assaying whether a particular glycan structure (A) is present on a protein of interest or not, preferably suitable for determining the amount of glycan structure (A) (in a sample). In other words, determining a glycan structure (A) may also be seen as a method of glycoprofiling the protein interest suspected to have the glycan structure (A) on it. Thus, this method provides the signal that is relativized (signal (1)) or is the basis for the relativizing (signal (2)). Suitable methods include, but are not limited to, enzyme-linked immunosorbent assay (ELISA), enzyme-linked lectin assay (ELLA), magnetic ELLA (MELLA), preferably ELLA or MELLA. Accordingly, signal (1) and signal (2) may be obtained by enzyme-linked immunosorbent assay (ELISA), enzyme-linked lectin assay (ELLA), magnetic ELLA (MELLA), preferably ELLA or MELLA. Preferably, signal (1) and signal (2) are obtained at the same conditions, including the same reagents at the same concentrations. The present invention is however not limited to these methods but may include any other assay method involving glycan analysis.
ELISA can be seen as the starting point to a variety of similar or ELISA-like assays. ELISA is based on the specific interaction of an immunoglobulin with a molecule of interest such as the glycan structure (A) suspected to be on the protein of interest, wherein the specific interaction allows the generation of a signal only in presence of the molecule of interest and the signal (strength) corresponds to the concentration of the molecule of interest in the analyzed sample. Assays like ELISA, ELLA and MELLA are known to a person skilled in the art. Various ELISA variations such as sandwich ELISA, competitive ELISA and reverse ELISA are further known in the art. In the context of the invention, the primary immunoglobulin, i.e. the immunoglobulin binding to the molecule of interest, binds to the glycan structure (A) suspected to be on the protein of interest. Thus, the primary immunoglobulin, preferably an antibody or a fragment thereof, specifically binds to a glycan structure (A) of interest. In ELLA, the primary immunoglobulin is replaced by a lectin, which binds specifically to a glycan structure (A). Magnetic ELLA (MELLA) is a further development of ELLA described in WO 2019/185515 A1, hereby incorporated by reference in its entirety. The readout of these assays, e.g. the signal intensity, can be seen as the signal (1) or signal (2) in the context of the invention. Typically, the readout is the result of an enzymatic reaction of an enzyme coupled to a second immunoglobulin that binds to the primary immunoglobulin, to the protein of interest (to the protein backbone of the glycoprotein of interest) or the lectin. Alternatively, the enzyme can (directly) be coupled to the lectin. Frequently used readouts include, but are not limited to, OPD (o-phenylenediamine dihydrochloride) turning amber to detect HRP (Horseradish Peroxidase), which is often used to as a conjugated protein; TMB (3,3′,5,5′-tetramethylbenzidine) turning blue when detecting HRP and turns yellow after the addition of sulfuric or phosphoric acid; ABTS (2,2′-Azinobis [3-ethylbenzothiazoline-6-sulfonic acid]-diammonium salt) turning green when detecting HRP; or PNPP (p-Nitrophenyl Phosphate, Disodium Salt) turning yellow when detecting alkaline phosphatase. In addition to these colorimetric readouts, also radiolabel, fluorescent label, electrochemical label, chemiluminescent label, colorimetric approach or even a label-free format (e.g. SPR) can be used. Another example is 10-acetyl-3,7-dihydroxyphenoxazine (Amplex® Red reagent) to detect hydrogen peroxide (H2O2) or peroxidase activity. In the presence of peroxidase, the Amplex® Red reagent reacts with H2O2 in a 1:1 stoichiometry to produce the red-fluorescent oxidation product, resorufin. Resorufin has excitation and emission maxima of approximately 571 nm and 585 nm.
The term “lectin” when used herein refers to a carbohydrate-binding protein. A lectin typically is highly specific for a carbohydrate moiety or carbohydrate moieties (e.g., it reacts specifically with terminal glycosidic residues of other molecules such as a glycan/s of a glycoprotein (e.g., branching sugar molecules of glycoproteins, e.g., such as target polypeptides within the meaning of the present invention and biomarkers as described in Table 1 herein). Lectins are commonly known in the art. A skilled person is readily available to determine which lectin may be used for binding a carbohydrate moiety or carbohydrate moieties of interest, e.g. a carbohydrate moiety or carbohydrate moieties of a glycan attached to a protein. Preferred lectins applied in the context of the present invention are described herein. Also included by the term “lectin” are Siglecs (sialic acid-binding immunoglobulin-like lectins), Galectins (lectins that bind specifically to β-galactoside containing glycans) and Selectins (bind to the sialyl Lewis X (SLex) determinant NeuAcα2-3Galβ1-4(Fucα1-3)GlcNAc and related sialylated, fucosylated glycans). Notably, the term “lectin” when used herein also refers to glycan-binding antibodies. Accordingly, the term “lectin” when used herein may also encompass lectins, Siglecs, Galectins, Selectins, etc. as well as glycan-binding antibodies. Lectins may also include DNA/RNA aptamers recognizing glycans.
Lectins can be obtained from seeds of leguminous plants, but also from other plant and animal sources. Lectins can contain binding sites for specific mono- and oligosaccharides (e.g., glycans of glycoproteins). They can agglutinate cells by binding to specific sugar residues in membrane glycoproteins. Preferably, lectins of the present invention are selected from the group consisting of: Maackia amurensis lectin II (MAA II); Concanavalin A (Con A); Aleuria aurantia lectin (AAL); Sambucus nigra (SNA-1) lectin; Wisteria floribunda lectin (WFL) as defined herein.
Further preferred lectins of the present invention are shown in Table 1 below.
Particularly preferred lectins of the present invention are lectins with the following UniProtKB Accession Numbers: P0DKL3, P02866, P18891, 004366, A0A218PFP3, Q945S3, Q00022, Q6YNX3, Q71QF2, P02872, P18670, Q2UNX8, Q8L5H4, A0A089ZWN7, P05045, P19588, P83410, P17931, P56470, P24146, Q41263, Q39990, Q2F1K8, G9M5T0, B3XYC5, P02870, P19664, P0DKL3, P49300, A9XX86, Q40423, P16300, P05088, P05087, Q9AVB0, P02867, O24313, Q9SM56, P06750, B9SPG3, Q9BZZ2, P20916, Q9NYZ4, Q96RL6, P05046, P93535, P02876, P10968, P10969, P22972 or P56625 as well as corresponding mature forms thereof.
Exemplary lectins of the present invention further include:
Maackia amurensis lectin II (MAA II) is the hemagglutinin isolectin from Maackia seeds. Sialic acid-binding lectin recognizing oligosaccharides containing terminal sialic acid linked via α2-3 bond to neighboring galactose residues. Binds the trisaccharide sequence Neu5Acα2-3-Gal-β-1-4-GlcNAc. Preferably, MAA II has a SEQ ID NO: 2 (or its mature form).
Concanavalin A (Con A) a D-mannose specific lectin originally extracted from the jack-bean, Canavalia ensiformis. Preferably, Con A has a SEQ ID NO: 3 or SEQ ID NO: 4 (Con A, mature form).
Aleuria aurantia lectin (AAL) is a fucose-specific lectin extracted from Aleuria aurantia (Orange peel mushroom). Preferably, AAL has a SEQ ID NO: 5 (or its mature form). The isolation of AAL is, for example, described in (Debray et al., Kochibe et al.).
Sambucus nigra (SNA-1) lectin is a Neu5Acα2-6)Gal/GalNAc specific agglutinin extracted from Sambucus nigra (European elder). Preferably, SNA-I has a SEQ ID NO: 6 (or its mature form). Wisteria floribunda lectin (WFL) is an agglutinin extracted from Wisteria floribunda (Japanese wisteria). Preferably, WFL has a SEQ ID NO: 7 (or its mature form).
Furthermore, suitable lectins within the meaning of the present invention may explicitly include post-translationally processed- and mature forms of the lectins as disclosed herein.
The term “antibody” also includes, but is not limited to, but encompasses monoclonal, monospecific, poly- or multi-specific antibodies such as bispecific antibodies, humanized, camelized, human, single-chain, chimeric, synthetic, recombinant, hybrid, mutated, grafted, and in vitro generated antibodies, with chimeric or humanized antibodies being preferred. The term “humanized antibody” is commonly defined for an antibody in which the specificity encoding CDRs of HC and LC have been transferred to an appropriate human variable frameworks (“CDR grafting”). The term “antibody” also includes scFvs, single chain antibodies, diabodies or tetrabodies, domain antibodies (dAbs) and nanobodies. In terms of the present invention, the term “antibody” shall also comprise bi-, tri- or multimeric or bi-, tri- or multifunctional antibodies having several antigen binding sites. Said term also includes antigen binding portion(s). Also included by the term “antibody” may be FN3 scaffold, adnectin, affibody, anticalin, avimer, a bicyclic peptide, DARPin, a Kunitz domain, an Obody or an aptamer, such as a DNA, RNA or peptide aptamer.
Preferred antibodies of the present invention include, but are not limited to, an anti-PSA, anti-AFP, anti-MUC16, anti-WFDC2, anti-MUC1, anti-ERBB2, anti-CEACAM5, anti-FUT3 or anti-TG antibodies etc. Further preferred antibodies relating to the present invention are shown in Table 1 below.
Furthermore, the term “antibody” as employed in the invention also relates to derivatives of the antibodies (including fragments) described herein. A “derivative” of an antibody comprises an amino acid sequence which has been altered by the introduction of amino acid residue substitutions, deletions or additions. Additionally, a derivative encompasses antibodies which have been modified by a covalent attachment of a molecule of any type to the antibody or protein. Examples of such molecules include sugars, PEG, hydroxyl-, ethoxy-, carboxy- or amine-groups but are not limited to these. In effect the covalent modifications of the antibodies lead to the glycosylation, pegylation, acetylation, phosphorylation, amidation, without being limited to these.
The protein of interest is not limited to a particular protein. In contrast and due to the versatility of the neoglycoprotein, the methods and uses of the invention can be applied to assay whether a particular glycan structure (A) is present on the protein of interest. However, the protein of interest preferably is a glycoprotein or, to put it differently, a protein which is suspected to have a glycan structure (A). Since the presence or absence of a glycan structure (A) on the protein of interest may be important for diagnosis or prognosis of a disease, the protein of interest preferably is a protein, whose glycoprofile is relevant for a disease. The term “glycoprotein” (or “glycosylated protein”) as used herein means a protein containing one or more N-, O-, S- or C-covalently linked carbohydrates of various types, e.g., ranging from monosaccharides to branched polysaccharides (including their modifications such as sulfo- or phospho-group attachment). N-linked glycans are carbohydrates bound to —NH2 group of asparagine. O-linked glycans are carbohydrates bound to —OH group of serine, threonine, or hydroxylated amino acids. S-linked glycans are carbohydrates bound to —SH group of cysteine. C-linked glycans are carbohydrates bound to tryptophan via C—C bond.
The term “carbohydrates” means compounds (e.g., such as aldoses and ketoses) having the stoichiometric formula Cn(H2O)n. The generic term “carbohydrate” includes monosaccharides, oligosaccharides and polysaccharides as well as substances derived from monosaccharides by reduction of the carbonyl group (alditols), by oxidation of one or more terminal groups to carboxylic acids, or by replacement of one or more hydroxy group(s) by a hydrogen atom, an amino group, thiol group or similar groups. It also includes derivatives of these compounds.
As already described herein, the presence of a particular glycan structure (A) on the protein of interest may be relevant for the diagnosis of a particular disease such as a cancer, an autoimmune disease or an inflammatory disease. Some combinations of proteins (of interest, i.e. biomarker proteins) and glycan structures (A) are known to be indicative for diseases. Specific combinations of proteins of interest and glycans indicative for diseases are exemplified in Table 1 as well as antibodies or lectins binding to the particular glycan structures. Thus, the method and uses of the present invention can be used in diagnosing of diseases such as cancer, autoimmune disease or inflammatory disease. Accordingly, the presence of said glycan structure (A) may be indicative of a disease such as cancer, autoimmune disease or inflammatory disease.
In this context, the protein of interest preferably is a cancer biomarker protein, an autoimmune disease biomarker protein or an inflammatory disease biomarker protein.
As used herein, an “autoimmune disease” refers a group of diseases characterized by disease associated with the production of antibodies directed against one's own tissues. Non-limiting examples of an autoimmune disease include, but are not limited to, Hashimoto's disease, primary biliary cirrhosis, systemic lupus erythematosus, rheumatic fever, rheumatoid arthritis, autoimmune hemolytic anemia, idiopathic thrombocytopenic purpura, and postviral encephalomyelitis, Addison's disease, autoimmune enteropathy, primary biliary cirrhosis, Goodpasture's syndrome, Hashimoto's thyroiditis, myasthenia gravis, myxoedema, pemphigoid, rheumatoid arthritis, Sjogren's syndrome, symphathetic ophthalmitis, both forms of lupus erythematosus, thyrotoxicosis, ulcerative colitis, multiple sclerosis, celiac disease, diabetes mellitus type 1, Graves' disease, inflammatory bowel disease and psoriasis.
As used herein, an “inflammatory disease” refers a group of diseases characterized by impairment and/or abnormal functioning of inflammatory mechanisms of the body. Non-limiting examples of an inflammatory disease include, but are not limited to, necrotizing enterocolitis, gastroenteritis, pelvic inflammatory disease (PID), empyema, pleurisy, pyelitis, pharyngitis, angina, arthritis, acne, urinary tract infections, Acne vulgaris, Asthma, Celiac disease, Chronic prostatitis, Colitis, Diverticulitis, Glomerulonephritis, Hidradenitis suppurativa, Hypersensitivities, Inflammatory bowel diseases, Interstitial cystitis, Mast Cell Activation Syndrome, Mastocytosis, Otitis, Pelvic inflammatory disease, Reperfusion injury, Rheumatic fever, Rheumatoid arthritis, Rhinitis, Sarcoidosis, Transplant rejection, Vasculitis.
As used herein, “cancer” refers a group of diseases characterized by the uncontrolled growth of abnormal cells in the body. Unregulated cell division may result in the formation of malignant tumours or cells that invade neighbouring tissues and may metastasize to distant parts of the body through the lymphatic system or bloodstream. Non-limiting examples of cancers include squamous cell carcinoma, small-cell lung cancer, non-small cell lung cancer, squamous non-small cell lung cancer (NSCLC), non NSCLC, glioma, gastrointestinal cancer, renal cancer (e.g. clear cell carcinoma), ovarian cancer, liver cancer, colorectal cancer, endometrial cancer, kidney cancer (e.g., renal cell carcinoma (RCC)), prostate cancer (e.g. hormone refractory prostate adenocarcinoma), thyroid cancer, neuroblastoma, pancreatic cancer, glioblastoma (glioblastoma multiforme), cervical cancer, stomach cancer, bladder cancer, hepatoma, breast cancer, colon carcinoma, and head and neck cancer (or carcinoma), gastric cancer, germ cell tumour, pediatric sarcoma, sinonasal natural killer, melanoma (e.g., metastatic malignant melanoma, such as cutaneous or intraocular malignant melanoma), bone cancer, skin cancer, uterine cancer, cancer of the anal region, testicular cancer, carcinoma of the fallopian tubes, carcinoma of the endometrium, carcinoma of the cervix, carcinoma of the vagina, carcinoma of the vulva, cancer of the oesophagus, cancer of the small intestine, cancer of the endocrine system, cancer of the parathyroid gland, cancer of the adrenal gland, sarcoma of soft tissue, cancer of the urethra, cancer of the penis, solid tumours of childhood, cancer of the ureter, carcinoma of the renal pelvis, neoplasm of the central nervous system (CNS), primary CNS lymphoma, tumour angiogenesis, spinal axis tumour, brain stem glioma, pituitary adenoma, Kaposi's sarcoma, epidermoid cancer, squamous cell cancer, T-cell lymphoma, environmentally-induced cancers including those induced by asbestos, virus-related cancers (e.g., human papilloma virus (HPV)-related tumour), and hematologic malignancies derived from either of the two major blood cell lineages, i.e., the myeloid cell line (which produces granulocytes, erythrocytes, thrombocytes, macrophages and mast cells) or lymphoid cell line (which produces B, T, NK and plasma cells), such as all types of leukaemia, lymphomas, and myelomas, e.g., acute, chronic, lymphocytic and/or myelogenous leukaemia, such as acute leukaemia (ALL), acute myelogenous leukaemia (AML), chronic lymphocytic leukaemia (CLL), and chronic myelogenous leukaemia (CML), undifferentiated AML (MO), myeloblastic leukaemia (MI), myeloblastic leukaemia (M2; with cell maturation), promyelocytic leukaemia (M3 or M3 variant [M3V]), myelomonocytic leukaemia (M4 or M4 variant with eosinophilia [M4E]), monocytic leukaemia (M5), erythroleukaemia (M6), megakaryoblastic leukaemia (M7), isolated granulocytic sarcoma, and chloroma; lymphomas, such as Hodgkin's lymphoma (HL), non-Hodgkin's lymphoma (NHL), B-cell lymphomas, T-cell lymphomas, lymphoplasmacytoid lymphoma, monocytoid B-cell lymphoma, mucosa-associated lymphoid tissue (MALT) lymphoma, anaplastic (e.g., Ki 1+) large-cell lymphoma, adult T-cell lymphoma/leukaemia, mantle cell lymphoma, angio immunoblastic T-cell lymphoma, angiocentric lymphoma, intestinal T-cell lymphoma, primary mediastinal B-cell lymphoma, precursor T-lymphoblastic lymphoma, T-lymphoblastic; and lymphoma/leukaemia (T-Lbly/T-ALL), peripheral T-cell lymphoma, lymphoblastic lymphoma, post-transplantation, lymphoproliferative disorder, true histiocytic lymphoma, primary central nervous system lymphoma, primary effusion lymphoma, lymphoblastic lymphoma (LBL), hematopoietic tumours of lymphoid lineage, acute lymphoblastic leukaemia, diffuse large B-cell lymphoma, Burkitt's lymphoma, follicular lymphoma, diffuse histiocytic lymphoma (DHL), immunoblastic large cell lymphoma, precursor B-lymphoblastic lymphoma, cutaneous T-cell lymphoma (CTLC) (also called mycosis fungoides or Sezary syndrome), and lymphoplasmacytoid lymphoma (LPL) with Waldenstrom's macroglobulinemia; myelomas, such as IgG myeloma, light chain myeloma, non-secretory myeloma, smouldering myeloma (also called indolent myeloma), solitary, plasmocytoma, and multiple myelomas, chronic lymphocytic leukaemia (CLL), hairy cell lymphoma; hematopoietic tumours of myeloid lineage, tumours of mesenchymal origin, including fibrosarcoma and rhabdomyosarcoma; seminoma, teratocarcinoma, tumours of the central and peripheral nervous, including astrocytoma, schwannomas; tumours of mesenchymal origin, including fibrosarcoma, rhabdomyosarcoma, and osteosarcoma; and other tumours, including melanoma, xeroderma pigmentosum, keratoacanthoma, seminoma, thyroid follicular cancer and teratocarcinoma, hematopoietic tumours of lymphoid lineage, for example T-cell and B-cell tumours, including but not limited to T-cell disorders such as T-prolymphocytic leukaemia (T-PLL), including of the small cell and cerebriform cell type; large granular lymphocyte leukaemia (LGL) preferably of the T-cell type; a/d T-NHL hepatosplenic lymphoma; peripheral/post-thymic T cell lymphoma (pleomorphic and immunoblastic subtypes); angiocentric (nasal) T-cell lymphoma; cancer of the head or neck, renal cancer, rectal cancer, cancer of the thyroid gland; acute myeloid lymphoma, as well as any combinations of said cancers. Preferred cancers are also shown in Table 1.
The cancer may also be an ovarian cancer, breast cancer, colorectal cancer, pancreatic cancer, prostate cancer, thyroid cancer, liver cancer, lung cancer, stomach cancer, testicular cancer or bladder cancer. Accordingly, the biomarker protein (protein of interest) may be an ovarian cancer biomarker protein, breast cancer biomarker protein, colorectal cancer biomarker protein, pancreatic cancer biomarker protein, prostate cancer biomarker protein, thyroid cancer biomarker protein, liver cancer biomarker protein, lung cancer biomarker protein, stomach cancer biomarker protein, testicular cancer biomarker protein or bladder cancer biomarker protein.
Exemplary cancers, cancer biomarkers with aberrant glycosylation, lectins, antibodies and corresponding glycan modifications within the meaning of the present invention are also shown in Table 1 below. Lectin abbreviations used in Table 1: Cancers, corresponding cancer biomarkers with aberrant glycosylation, lectins and antibodies.: AAA—Anguilla anguilla agglutinin (UniProtKB Accession Number: Q7SIC1), AAL—Aleuria aurantia lectin, ABA—Agaricus bisporus agglutinin, ACA—Amaranthus caudatus agglutinin, AHA—Arachis hypogaea agglutinin=peanut agglutinin (PNA), AIA—Artocarpus integrifolia agglutinin=Jacalin, AIIoA—Allomyrina dichotoma agglutinin, AOL—Aspergillus oryzae lectin, BanLec—Musa paradisiaca lectin, BS-1—Bandeiraea simplicifolia lectin=Griffonia (Bandeiraea) simplicifolia lectin I, Con A Concanavalin A, DBA—Dolichos biflorus agglutinin, DSA—Datura stramonium agglutinin (Jacalin), ECL—Erythrina cristagalli lectin, GNA—Galanthus nivalis agglutinin, GSA I (GSL I)—Griffonia (Bandeiraea) simplicifolia lectin I, GSL II—Griffonia (Bandeiraea) simplicifolia lectin II, HHL—Hippeastrum hybrid (Amaryllis) lectin, HPA—Helix pomatia agglutinin, LBA—Phaseolus lunatus (lima bean, LBA), LEL—Lycopersicon esculentum (tomato) lectin, LCA—Lens culinaris agglutinin, LTA—Lotus tetragonolobus lectin, MAA I—Maackia amurensis agglutinin I, MAA II—Maackia amurensis agglutinin II, MGBL 1—macrophage galactose binding lectin 1, MGBL 2 (macrophage galactose binding lectin 2, NPA—Narcissus pseudonarcissus (Daffodil) lectin, PHA E—Phaseolus vulgaris agglutinin E, PHA L—Phaseolus vulgaris agglutinin L, PhoSL—Pholiota squarrosa lectin, PNA—Peanut agglutinin, PSL—Pisum sativum lectin, PTA I—Psophocarpus tetragonolobus lectin I, PTA II—Psophocarpus tetragonolobus II, PWM—Phytolacca americana, RCA I—Ricinus communis agglutinin I, RCA II—Ricinus communis agglutinin II, SBA—Soybean agglutinin (Glycine max agglutinin), SCA—Sambucus canadensis agglutinin=Sambucus nigra agglutinin (SNA), SJA—Sophora japonica agglutinin II, SNA—Sambucus nigra agglutinin, SSA—Sambucus sieboldiana agglutinin, SSL—Salvia sclarea lectin, STL—Solanum tuberosum lectin, TJA-I—Trichosanthes japonica agglutinin I, TJA-b—Trichosanthes japonica agglutinin (Yamashita et al.), TVA—Triticum vulgaris agglutinin=WGA wheat germ agglutinin, UEA—Ulex europaeus agglutinin, WVA—Vicia villosa lectin, WFA—Wisteria floribunda lectin, WGA—wheat germ agglutinin=TVA—Triticum vulgaris agglutinin. The symbol “↑”, an upward pointing arrow means increase in concentration of a corresponding glycan/s or a complex/s (e.g., dimer, trimer etc). The symbol “↓”, a downward pointing arrow means increase in concentration of a corresponding glycan/s or a complex/s (e.g., dimer, trimer etc).
References as shown in Table 1 are as follows:
It is noted that as used herein, the singular forms “a”, “an”, and “the”, include plural references unless the context clearly indicates otherwise. Thus, for example, reference to “a reagent” includes one or more of such different reagents and reference to “the method” includes reference to equivalent steps and methods known to those of ordinary skill in the art that could be modified or substituted for the methods described herein.
Unless otherwise indicated, the term “at least” preceding a series of elements is to be understood to refer to every element in the series. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the present invention.
The term “and/or” wherever used herein includes the meaning of “and”, “or” and “all or any other combination of the elements connected by said term”.
The term “less than” or in turn “more than” does not include the concrete number.
For example, less than 20 means less than the number indicated. Similarly, more than or greater than means more than or greater than the indicated number, e.g. more than 80% means more than or greater than the indicated number of 80%.
Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integer or step. When used herein the term “comprising” can be substituted with the term “containing” or “including” or sometimes when used herein with the term “having”. When used herein “consisting of” excludes any element, step, or ingredient not specified.
The term “including” means “including but not limited to”. “Including” and “including but not limited to” are used interchangeably.
As used herein the terms “about”, “approximately” or “essentially” mean within 20%, preferably within 15%, preferably within 10%, and more preferably within 5% of a given value or range. It also includes the concrete number, i.e. “about 20” includes the number of 20.
It should be understood that this invention is not limited to the particular methodology, protocols, material, reagents, and substances, etc., described herein and as such can vary. The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention, which is defined solely by the claims.
All publications cited throughout the text of this specification (including all patents, patent application, scientific publications, instructions, etc.), whether supra or infra, are hereby incorporated by reference in their entirety. Nothing herein is to be construed as an admission that the invention is not entitled to antedate such disclosure by virtue of prior invention. To the extent the material incorporated by reference contradicts or is inconsistent with this specification, the specification will supersede any such material.
The content of all documents and patent documents cited herein is incorporated by reference in their entirety.
An even better understanding of the present invention and of its advantages will be evident from the following examples, offered for illustrative purposes only. The examples are not intended to limit the scope of the present invention in any way.
Unconjugated streptavidin (˜55 kDa, not glycosylated), MAA-II (-130 kDa) and anti-streptavidin antibody (˜150 kDa) was purchased from Vector Labs, US. Glycan 3′-sialyllactosamine-PEG3-biotin (single arm, −1100 Da) was obtained from Sussex Research, Canada. Desalting columns (MWCO=7000 Da) were purchased from Thermo, US. All common chemicals, such as buffer components etc., were purchased from Sigma Merck, US. For all experiments, ultra pure deionized water (G=0.055 μS) was used. All buffers were filtered prior to use using 0.22 μm sterile filters.
All reagents used for SPR were purchased from GE Healthcare including HBS-P+ (Buffer 10×; BR-1006-71), Coupling Kit (BR100050), EDC (0.4 M), NHS (0.1 M), ethanolamine hydrochloride (1 M; pH 8.5). For regeneration NaOH (50 mM; BR-1003-58) and for coupling acetate buffer pH 4.0 (BR-1003-51) was used. SPR assays were run on BiacoreX100 (GE Healthcare) using a sensor chip CM5 (29-1496-04) or Au chip modified using 11-mercaptoundecanoic acid (5 mM in UVNIS ethanol, Sigma Merck, US; incubated at RT overnight) under a constant flow rate of 30 μL/min at 25° C. Original SW Biacore X100 Control Software was used to run the instrument.
All samples were diluted in 0.1 M PB (pH 7.4, 0.22 μm filtered) and measured in continual flow (a total volume of 500 μl was prepared for a single run). Measurement concentrations were found by pretesting the ideal particle per frame value (20-100 particles/frame), as suggested. Following settings were set according to the manufacturer's software manual for NanoSight NS300: the detection threshold was determined to include as many particles as possible with the restrictions that 10-100 red crosses were counted. Blue cross count was limited to minimum. Autofocus was adjusted so that indistinct particles were avoided. For each measurement, five 60 s videos were captured under the following conditions: cell temperature: 25° C.; syringe speed: 10 μl/min. After captures, the videos have been analyzed by the in-build NanoSight Software NTA 3.1 Build 3.1.46 with a detection threshold=10.
Lyophilized streptavidin powder was resuspended in a sterile 0.1 M PB (pH 7.4) to obtain a concentration of 1 mg·ml−1. For known concentration of biotinylated glycan, these two solutions were mixed in 1+5 molecules ratio for an hour at 37° C. with gentle mixing (500 rpm). Finally, this neoglycoprotein was purified of redundant glycans using Zeba Spin desalting column with 7 k MWCO (previously equilibrated using PB) at 3000 rpm for 1 min. Neoglycoprotein was obtained at c=˜0.9 mg·ml−1 and was stored at 4° C. for the rest of the experimental work.
SPR binding analysis In the first run, a carboxymethyl-dextran CM5 SPR chip was used to find an optimal immobilization pH value and subsequently for immobilization of a ligand on the sensor surface. Optimal pH for all cases was 4.0 (
To confirm a successful preparation of a sandwich (MAA-II/glycan-streptavidin/antibody), a 2D chip was prepared by immersing bare Au chip into 5 mM ethanol solution of 11-mercaptoundecanoic acid (RT, dark, overnight). An advantage of this approach is that basically all negative charges (carboxy groups) are localized on the surface and are removed after immobilization/blocking. The whole sandwich preparation, as well as the assay workflow, is shown on
A detailed overview of the conditions applied for each step is summarized in following Table 2.
For NTA analysis to observe the modification of magnetic nanoparticles (MNPs, 130 nm COOH terminated, dextran-coated nanomags), all three samples, i. e. bare MNPs, Ab-modified MNPs MNPs+Ab) and neoglycoprotein-enriched Ab-modified MNPs (MNPs+Ab+C) were treated equally, whether using a specific chemical/component or PB in case of blank—all three samples were therefore separated the same way/same number of times. Using spherical interface for biorecognition yields higher signal in this case, since the ligand density is decreased with longer linker molecules, decreasing sterical hindrance for MELLBA compared to planar surface used for SPR experiments above (
While unmodified (but equal number of times separated) MNPs yielded almost exclusively one single peak with d≤140 nm, while after Ab conjugation (amine coupling, 10 min, RT) there are two major fractions—(i)≤120 nm (slightly less compared to unmodified particles) and about 20% of (ii)≤150 nm. After incubation of these particles with purified neoglycoprotein, at least four different fractions could be observed—even larger aggregates occurred at ˜220 nm. Decrease of hydrodynamic diameter (dH) in process 1 (ab immobilization) is caused by “compressing” of dextran matrix around immobilized ab in case the binding capacity of MNPs is not saturated during the immobilization process (hypothesis). Otherwise, dHincreases, as in
Different streptavidin+biotinyl-glycan ratios were used (i. e. 1+0, 1+1, 1+2, 1+3, 1+4, 1+5, 1+6 and 1+7 ratios of number of molecules per volume) to prepare fully glycosylated protein standard. MALDI-TOF mass spectrometry (Bruker, USA) and previously optimized protocol (using 2,5-dihydroxyacetophenone (DHA) matrix) was used to detect mass fragments (m/z parameter) for ionized sample components, as described previously elsewhere. In
For this purpose, enzyme-linked lectin binding assay (ELLBA) has been used to find the full saturation ratio. The assay configuration is depicted in
The neoglycoprotein (protein standard) made by attachment of biotinylated glycans to the streptavidin was simultaneously recognised by the MAA-II lectin and by the anti-streptavidin antibody. This unexpected finding shows that such a neoglycoprotein can be applied as a protein standard for ELISA-like formats of analysis (including MELLA).
Experimental work showed that a glycoprotein standard—also referred to herein as neoglycoprotein (standard) or standard of the present invention, e.g. as the standard applied in Example 1, above—is stable for at least 1 week when stored at 4° C. Such a standard can be prepared in a highly reproducible way i.e. RSD of 8.17% for preparation of glycoprotein standard in 17 independent preparation batches within 18 weeks.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21190083.2 | Aug 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/072138 | 8/5/2022 | WO |
