Glycosaminoglycan-modified protein, process for the production of this protein, use and pharmaceutical compositions containing the same

Abstract: A glycosaminoglycan-modified protein wherein an amino group of a protein is bound to an aldehyde group, which has been formed by reducing and partially oxidizing the reducing terminal sugar moiety of a glycosaminoglycan, which has a high stability in vivo and can retain physiological activity of the protein for a prolonged period of time.

Description: FIELD OF THE INVENTION This invention relates to a protein modified with a glycosaminoglycan. More particularly, it relates to a protein modified with a glycosaminoglycan which is obtained by reacting a glycosaminoglycan activated with a specific activator with a protein. BACKGROUND OF THE INVENTION Recently, attempts have been frequently made to apply enzymes and physiologically active proteins as drugs for treating various diseases including cancer, inflammation and hereditary enzyme deficiency. However, many of these enzymes and physiologically active proteins are heterogenic to living organisms. Thus the administration of these compounds as such to an organism would cause a problem of immunogenicity or deteriorate the stability in vivo . When such a compound is to be formulated into a medicine, therefore, it is required to relieve an anaphylatic reaction and to improve the prolonged drug effect. Furthermore, attempts have been made to produce these proteins in a large amount through genetic engineering techniques. However, proteins produced by genetic engineering suffer from a problem of the deficiency of a sugar chain, which seriously affects the stability in vivo . Accordingly, there has been proposed to modify an enzyme or a physiologically active protein with various synthetic polymers or polysaccharides so as to pharmacologically improve the stability thereof. Examples of the synthetic polymers employed therefor include poly-L-aspartic acid (M. Okada, A. Matsushima, A. Katsuhata, T. Aoyama, T. Ando and Y. Inada: Int. Archs Allergy Appl. Immun. 76 , 79 - 81 (1965)) and derivatives thereof, poly-D- or -L-lysine, D-glutamic acid/D-lysine copolymer (F.T. Liu and D.H. Katz: Proc. Natl. Acad. Sci. USA, 76 , 1430 - 1434 (1979)), polyvinyl alcohol pyran copolymer, polyethylene glycol and derivatives thereof and styrene/maleic acid copolymer (H. Maeda, M. Ueda, T. Morinaga and T. Matsumoto: J. Med. Chem., 28 , 455 - 461 (1985)). Examples of the polysaccharides include agarose, carboxymethyl cellulose, dextran (T.P. King, L. Kochoumian, K. Ishizaka, L. Kichtenstein, P.S. Norman: Arch. Biochem. Biophys., 169 , 464 - 473 (1975)), pullulan (M. Usui and T. Matsuhashi: J. Immunol., 122 , 1266 - 1272 (1979) and N. Matsuhashi: Genkansa no Jikken Dobutsu Moderu (Experimental Animal Model for Hyposensitization), ed. by S. Kobayashi et al., Genkansa Ryoho no Kiso to Rinsho (Bases and Clinical Application of Hyposensitization Therapy), 4 - 11, Chugai Igakusho (1982)) and lipopolysaccharide. On the other hand, U.S. Patent 4,485,754 proposes a stabilized protein which is obtained by reacting a protein such as superoxide dismutase or insulin with chondroitin sulfate in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. However, the protein thus obtained is in the form of a complicated polymer involving a polymer of the protein per se, since plural carboxyl groups in aspartic acid or glutamic acid contained in the protein are activated by 1-enthyl-3-(3-dimethylaminopropyl)carbodiimide, respectively. Thus, this product should be further improved from the viewpoint of the pharmacological effect of the unmodified superoxide dismutase or insulin as a monomer. SUMMARY OF THE INVENTION An object of the present invention is to provide a glycosaminoglycan-modified protein, which is highly stable in vivo and can express the inherent physiological effect of the starting protein for a prolonged period of time without forming any polymer of a complicated structure. The above object of the present invention can be achieved by a glycosaminoglycan-modified protein obtained by reacting glycosaminoglycan activated by reducing terminal residue-lactonization method with a protein. According to an embodiment of the present invention, a glycosaminoglycan-modified protein of the following formula: wherein P represents a protein residue exclusive of n amino groups from the protein; n is an integer of from 1 to 100 and GAG represents a glycosaminoglycan residue exclusive of the reducing terminal sugar moiety from the glycosaminoglycan is provided. In Fig. 1, Lane 1 stands for the electrophoretic pattern of SOD derived from bovine red blood cell, Lane 2 stands for the pattern of SOD derived from dog red blood cell, Lane 3 stands for the pattern of HA-modified SOD derived from dog red blood cell, and Lane 4 stands for HA-modified SOD derived from bovine red blood cell. DETAILED DESCRIPTION OF THE INVENTION The glycosaminoglycan-modified protein of the present invention may be produced by, for example, reacting a glycosaminoglycan activated by reducing terminal residue-lactonization method with a protein. The process for production of glycosaminoglycan-modified protein of the present invention is described in detail below. Reducing terminal residue-lactonization method This method comprises partially oxidizing the reducing terminal sugar moiety of a glycosaminoglycan to thereby cleave the terminal sugar moiety followed by forming a lactone. Then, a protein modified with the glycosaminoglycan is prepared by reacting the lactone with an amino group of the protein. The reaction scheme of this method is as follows: Reaction scheme B In the above reaction scheme, R¹ = OH, R² = CH₂OH, A represents a potassium or sodium atom; and P, n, GAG. In this method, the glycosaminoglycan of the formula (II) is first oxidized to cleave the reducing terminal sugar moiety. Thus, a carboxyl compound of the formula (III) is obtained. Examples of the oxidizing agent to be used in this oxidation step include iodine and bromine. The oxidizing agent may be used usually in an amount of from 2 to 20 equivalents, preferably from 5 to 15 equivalents, per mole of the compound of the formula (II). The oxidation reaction may be conducted in a liquid medium selected from among, for example, a buffer solution such as borate buffer solution (pH 8.3), phosphate buffer solution (pH 8.6) or a mixture of such a buffer solution with an organic solvent such as dimethylformamide, acetonitrile or dioxane, methanol at a temperature of from 0 to 40°C, preferably from 15 t 20°C. After the oxidation reaction, potassium hydroxide or sodium hydroxide is added to the reaction mixture to decompose the remaining oxidizing agent. The thus-obtained solution containing the compound of the formula (III) is applied to a column packed with 200 ml of strongly acidic cation exchange resins such as Dowex 50 and Amberlite IR120 and allowed it to pass through the column over 1 hour to obtain the passed-through fraction. The column is washed with water, this water fraction is combined with the above-obtained passed-through fraction and then the combined fraction is allowed to stand overnight at 4 °C to form the lactone compound of the formula (IV). The lactone compound of the formula (IV) thus obtained is then reacted with a protein to give the glycosaminoglycan-modified protein represented by the formula (I). The reaction between the lactone compound of the formula (IV) and the protein may be conducted by reacting the lactone in the form of a trialkylamine or adjusting the pH value of a mixture of the lactone and the protein to 4 to 7 with an aqueous solution of sodium hydroxide followed by effecting the reaction at 0 to 70 °C, preferably 15 to 50 °C. Regarding the glycosaminoglycan-modified protein of the formula (I), n may generally range from an integer of 1 to 100, preferably from 1 to 10 on average. The glycosaminoglycan-modified protein produced by the above-mentioned method may be separated and purified by a conventional method. For example, the reaction mixture is desalted with the use of a dialysis membrane or an ultrafiltration membrane. Then, the desired product is separated from the unreacted glycosaminoglycan and protein and purified with the use of an anion exchanger or a cation exchanger. Alternately, the product may be separated and purified by gel filtration by taking advantage of the difference in molecular weight. In the cases of some proteins, furthermore, it is possible to separate and purify the desired product by affinity chromatography using a carrier on which an enzyme inhibitor, a substrate or an antibody is immobilized. The glycosaminoglycan employed in the present invention for modifying a protein may be selected over a wide range depending on the required characteristics of the desired glycosaminoglycan-modified protein and the purpose of the modification, without particular restriction. More particularly, it may be selected from among coromic acid, hyaluronic acid, chondroitin, chondroitin sulfate, teichuronic acid, dermatan sulfate, heparin, heparan sulfate, keratosulfate, keratopolysulfate and derivatives thereof such as chondroitin polysulfate. When the desired product is used as an antithrombotic agent and an antiarteriosclerotic agent, preferred glycosaminoglycans are chondroitin sulfate, chondroitin polysulfate, heparin, heparan sulfate and dermatan sulfate. On the other hand, hyaluronic acid, dermatan sulfate and chondroitin sulfate are suitable for the production of an antirheumatic agent and an antiinflammatory agent. These glycosaminoglycans can be used alone or in combination of two or more. The protein to be modified with the glycosaminoglycan is not particularly restricted. Usable as the proteins are physiologically active proteins originating from various animals including human, microorganisms and plants as well as those produced by chemical synthesis or using genetic engineering techniques. Specific examples of the proteins include cytokines (for example, various interferons such as interferon-α, interferon-β and interferon-γ, interleukin-2, interleukin-3), hormones [for example, insulin, growth hormone-releasing factor (GRF), calcitonin, calcitonin gene-relating peptide (CGRP), atrial natriuretic hormone (ANP), vasopressin, corticotropin-releasing factor (CRF), vasoactive intestinal peptide (VIP), secretin, α-melanocyte-stimulating hormone (α-MSH), adrenocorticotropic hormone (ACTH), cholecystokinin (CCK), glucagon, parathyroid hormone (PTH), parathyroid hormone-relating protein (PTHrP), somatostatin, enkephalin], growth factors [for example, growth hormone (GH), insulin-like growth factor (IGF-I, IGF-II), β-nerve growth factor (β-NGF), basic fibroblast growth factor (bFGF), transforming growth factor-β (TGF-β), erythropoietin, granulocyte colony stimulating factor (G-CSF), granulocyte macrophage colony stimulating factor (GM-CSF), platelet-derived growth factor (PDGF), epidermal growth factor (EGF)], enzymes [for example, tissue plasminogen activator (TPA), elastase, superoxide dismutase (SOD), bilirubin oxidase, catalase, uricase, urokinase, thermolysin, trypsin, chymotrypsin, Vs protease, pepsin, papain, hyaluronidase, chondroitin ABC lyase, asparaginase] and other proteins [for example, ubiquitin, insulin secretion-activating protein (IAP), serum thymus factor (STF), peptide-T, albumin, globulin, transferrin, lipoprotein, lipid A derivative, Ornithonyssus protein, trypsin inhibitor]. In the glycosaminoglycan-modified protein of the present invention, a glycosaminoglycan residue is chemically bound to a protein. The amount of the glycosaminoglycan to be introduced into the protein may vary depending on, for example, the protein and/or glycosaminoglycan, its molecular weight and the final usage of the formed glycosaminoglycan-modified protein. However, the suitable introduction amount of each glycosaminoglycan may be easily determined by those skilled in the art by simple experiments. Generally, the glycosaminoglycan may be introduced into the protein in an amount of from 1 to 99.9 % by weight, preferably from 90 to 95 % by weight, based on the weight of the protein to be modified. A glycosaminoglycan-modified protein hardly react with the antibody corresponding to the unmodified protein. Furthermore, the antibody productivity of the protein is substantially lowered by the modification. Further, when the glycosaminoglycan-modified protein is administered to a living organism, its activity is sustained for a long time, compared with the activity of the corresponding unmodified protein. Thus, the glycosaminoglycan-modified protein shows an improved stability in vivo . Drugs containing the glycosaminoglycan-modified protein of the present invention may be formulated into various forms for oral administration, for example, granules, fine subtilaes, powders, tablets, capsules, syrups, troches, suspensions or solutions. Alternately, the glycosaminoglycan-modified protein may be orally administered as such. Alternately, it may be formulated into injections for intravenous, intra-arterial, intraportal, intrapleuroperitoneal, intramuscular, subcutaneous or intratumor administration. Furthermore, it may be in the form of a powder and formulated into an injection upon use. It may be formulated into suppositories for per rectum or ointments for parenteral administration. These preparations may be formulated together with known organic or inorganic liquid or solid pharmaceutical carriers, diluents, binders, disintegrating agents and the like suitable for oral, parenteral or per rectum administration. (e.g., lactose, sucrose, glucose, starch, gum arabic, tragacanth gum). Furthermore, stabilizers, humectants, emulsifiers, aromatics and components for varying osmotic pressure may be added thereto. Examples thereof include gelatin, glycerol, vaseline, wax, plastics and higher alcohol. Furthermore, salts may be optionally used as an assistant ingredient for maintaining the pH value of the formulation at an appropriate level. For suppositories, a water-soluble or hydrophilic base such as macrogol or an oily base such as cacao oil may be used. The dose of the glycosaminoglycan-modified protein of the present invention may vary depending on the disease to be treated and symptoms and age of the patient. It is preferable to continuously or intermittently administer the compound to a patient in a dose of from 1 to 5000 mg/day in the case of oral administration or from 1 to 100 mg/day in the case of injection. To further illustrate the present invention, and not by way of limitation, the following Examples are given. In the following Examples, the activity and molecular weight of the GAG-modified proteins and the content of glycosaminoglycans and proteins were determined under the following conditions. Determination of activity Superoxide dismutase: One unit of enzyme is defined as the amount of the enzyme inhibiting 50 % of the activity of xanthine oxidase at pH 7.8 and 25°C. Determination of molecular weight A sample is subjected to high performance liquid chromatography using a G6000PWx2 (Tosoh Corporation) column. Elution was carried out with a 0.2 M sodium chloride aqueous solution. The molecular weight of a sample is determined based on a calibration curve. Determination of content of glycosaminoglycan (1) Glycosaminoglycan containing uronic acid A sample is subjected to carbazole-sulfuric acid reaction in accordance with the method as described in T. Bitter and H. M. Muir, Analytical Biochemistry, 4, 330-334 (1962). (2) Glycosaminoglycan containing no uronic acid A sample is subjected to phenol-sulfuric acid reaction in accordance with the method described in M. Dubois, K. A. Gilles, J. K. Hamilton, P. A. Rebers and F. Smith, Anal. Chem., 28 , 350-356 (1956). Determination of content of protein The content of a protein is determined by the method of Lowry et al. as described in O. H. Lowry, N. J. Rosenbrough, A. L. Farr and R. J. Randall, J. Biol. Chem., 193 , 265-275 (1951). EXAMPLE 1 Preparation of GAG-modified protein by reducing terminal residue-lactonization method: A. Preparation of reducing terminal residue-lactonized hyaluronic acid: 500 mg of hyaluronic acid (MW 10,000) was dissolved in 50 ml of water. 5 ml of a 0.1 M iodine solution in methanol was added thereto and the resulting mixture was allowed to react at room temperature for 6 hours. Then, approximately 5 ml of 0.1 N potassium hydroxide was added to the reaction mixture so as to cause the discoloration of the liberated iodine. Ethanol saturated with potassium acetate was added to the solution. The precipitate thus formed was collected by filtration and dissolved in 50 ml of water. The resulting solution was contacted with 50 ml of a strongly acidic ion exchange resin [Dowex 50(H⁺)] at 5 °C for 20 hours. The filtrate thus obtained was neutralized with tri-n-butylamine. The excessive amine was removed with ether and the residue was lyophilized. Thus, tri-n-butylamine of reducing terminal residue-lactonized hyaluronic acid was obtained as white powder. Lot No. 310. Yield: 410 mg. Reducing sugar determined by Somogyi-Nelson's method: none. B. Preparation of protein modified with reducing terminal residue-lactonized glycosaminoglycan I. Preparation of hyaluronic acid-modified peptide (H-Arg-Gly-Asp-Val-NH₂; RGDV): 60 mg of the product of lot NO. 310 was dissolved in 20 ml of dimethylformamide and 2.5 mg of a dimethylformamide solution of RGDV was added thereto. The resulting mixture was allowed to react at 60 °C for 2 hours. 10 ml of a 25 % aqueous solution of sodium acetate was added to the reaction mixture and the resulting mixture was allowed to stand at room temperature for 30 minutes. Then, ethanol was added thereto and the precipitate thus formed was collected by filtration. The filtrate was treated with an ultrafiltration device provided with a membrane of a fractionating molecular weight of 5000 to remove the unreacted RGDV. Then, the filtrate was lyophilized. The characteristics of hyaluronic acid-modified RGDV were as follows: Lot No. 320. Yield: 40.2 mg. RGDV content: 3.3 %. Hyaluronic acid content: 96.7 %. and In the above formulae, X is a hydrogen atom of non-reducing terminal residue of hyaluronic acid. EXAMPLE 2 Preparation of hyaluronic acid-modified superoxide dismutase 400 mg of comb-derived hyaluronic acid (MW 150,000) was dissolved in 2 M phosphate buffer (pH 11.5) and 1 ml of an acetonitrile solution of cyanogen bromide (100 mg/ml) was added thereto to allow the resulting mixture to react at 4°C for 5 minutes. Immediately after the termination of the reaction, 150 ml of acetonitrile was added to the reaction mixture to form precipitate. The thus-obtained precipitate was washed quickly with acetonitrile and was dissolved in 0.1 M sodium hydrogencarbonate solution. 10 ml of a 1% solution of superoxide dismutase (SOD) derived from dog red blood cell was added to the reation mixture and the reaction was carried out at 4°C for 20 hours. Ethanol was added to the reaction mixture to form precipitate and the resulting precipitate was dissolved in water. After adding 0.1 ml of ethanol amine to the mixture, the reaction was carried out at room temperature for one hour. Ethanol was added to the reaction mixutre to obtain precipitate and the thus-obtained precipitate was washed with ethanol well and dried to obtain hyaluronic acid-modified SOD. The characteristics of the hyaluronic acid-modified SOD thus obtained were as follows. Yield: 350 mg SOD content: 21.2% Hyaluronic acid content: 78.8% Molecular weight: 172,000 Activity: 82.1% of that of unmodified SOD Electrophoresis: cf. Fig. 1.

Claims: Claims for the following Contracting States : AT, BE, CH, DE, DK, FR, GB, IT, LI, LU, NL, SE A glycosaminoglycan-modified protein represented by the formula: wherein P represents a protein residue exclusive of n amino groups from the protein; n is an integer of from 1 to 100; and GAG represents a glycosaminoglycan residue exclusive of a reducing terminal sugar moiety from the glycosaminoglycan. A glycosaminoglycan-modified protein according to claim 1, wherein the glycosaminoglycan content ranges from 1 to 99.9% by weight based on the weight of the protein. A glycosaminoglycan-modified protein according to claim 1, wherein the glycosaminoglycan is selected from colominic acid, hyaluronic acid, chondroitin, chondroitin sulfate, teichuronic acid, dermatan sulfate, heparin, heparan sulfate, keratosulfate, keratopolysulfate and derivatives thereof. A glycosaminoglycan-modified protein according to claim 1, which is obtainable by oxidizing a reducing terminal sugar moiety of a glycosaminoglycan, treating the reducing terminal sugar moiety-oxidized glycosaminoglycan with an acid and reacting the glycosaminoglycan with a protein. A process for the production of a glycosaminoglycan-modified protein of claim 1 which comprises partially oxidizing the reducing terminal sugar moiety of said glycosaminoglycan to thereby cleave the terminal sugar moiety followed by forming a lactone therefrom and reacting the activated glycosaminoglycan with a protein. A pharmaceutical composition containing a glycosaminoglycan-modified protein of one of the claims 1 to 4 and a pharmaceutically acceptable carrier or diluent. Use of a glycosaminoglycan-modified protein according to one of the claims 1 to 4 for preparing a pharmaceutical composition for the treatment of various diseases including cancer, inflammation and hereditary enzyme deficiency. Claims for the following Contracting States : ES, GR Process for the production of a glycosaminoglycan-modified protein represented by the formula: wherein P represents a protein residue exclusive of n amino groups from the protein; n is an integer of from 1 to 100; and GAG represents a glycosaminoglycan residue exclusive of a reducing terminal sugar moiety from the glycosaminoglycan, which comprises oxidizing a reducing terminal sugar moiety of a glycosaminoglycan, treating the reducing terminal sugar moiety-oxidized glycosaminoglycan with an acid and reacting the glycosaminoglycan with a protein. Process for the production of a glycosaminoglycan-modified protein represented by the formula: wherein P represents a protein residue exclusive of n amino groups from the protein; n is an integer of from 1 to 100; and GAG represents a glycosaminoglycan residue exclusive of a reducing terminal sugar moiety from the glycosaminoglycan, which comprises partially oxidizing a reducing terminal sugar moiety of said glycosaminoglycan to therby cleave the terminal sugar moiety followed by forming a lactone therefrom and reacting the activated glycosaminoglycan with a protein. Process for the production of a glycosaminoglycan-modified protein according to claim 1 or 2, wherein the glycosaminoglycan content ranges from 1 to 99.9% by weight based on the weight of the protein. Process for the production of a glycosaminoglycan-modified protein according to claim 1 or 2, wherein the glycosaminoglycan is selected from colominic acid, hyaluronic acid, chondroitin, chondroitin sulfate, teichuronic acid, dermatan sulfate, heparin, heparan sulfate, keratosulfate, keratopolysulfate and derivatives thereof. Use of a glycosaminoglycan-modified protein obtained by a process according to one of the claims 1 to 4 for preparing a pharmaceutical composition for the treatment of various diseases including cancer, inflammation and hereditary enzyme deficiency.

Inventors: MIYAZAKI KYOSUKE, SAKURAI KATSUKIYO, MIYAZAKI, KYOSUKE, SAKURAI, KATSUKIYO
Applicants: SEIKAGAKU KOGYO CO LTD, SEIKAGAKU KOGYO KABUSHIKI KAISHA (SEIKAGAKU CORPORATION)
Application year: 1990
Main classification: C07K17
IPC codes: C07K14, C08B37, C07K1, C07K5, A61K47, C07K9, A61K38, C12N9