The present invention relates to novel human hyaluronidase variants having increased enzymatic activity and thermal stability compared to human hyaluronidase which is an enzyme that hydrolyzes hyaluronic acid, and more particularly to hyaluronidase PH20 variants or fragments thereof, which comprise one or more amino acid residue substitutions in the region corresponding to the alpha-helix region and/or its linker region in wild-type PH20 having the amino acid sequence of SEQ ID NO: 1, preferably mature wild-type PH20 consisting of amino acid residues L36 to S490, and in which one or more of the N-terminal or C-terminal amino acid residues are selectively deleted, a method for producing the same, and a pharmaceutical composition comprising the same.
The human skin is composed of epidermis, dermis and a subcutaneous fat layer, and there are six types of glycosaminoglycans in the skin. These glycosaminoglycans include hyaluronic acid, chondroitin sulfate, dermatan sulfate, heparan sulfate, heparin, and keratin sulfate.
These glycosaminoglycans are composed of repeating disaccharide sugar units. The number of the disaccharide sugar units is different among the glycosaminoglycans, but ranges from several hundreds to thousands. Among the glycosaminoglycans, hyaluronic acid is present in the skin more than half of the amount in the body. Hyaluronic acid is synthesized by hyaluronan synthase present in the cell membrane, is present alone without binding to proteoglycans, and is the only glycosaminoglycan having no sulfate group. Other glycosaminoglycans bind to proteoglycans and have a sulfate group. Hyaluronic acid consists of glucuronic acid and N-acetylglucosamine linked via alternating β-1,4 and β-1,3 bonds, and is composed of about 5,000 repeating units of these disaccharides. It is known that about one-third (5 g) of hyaluronic acid in the human body is turned over every day.
Hyaluronidases are enzymes that degrade hyaluronic acid present in the extracellular matrix. It is known that there are six types of hyaluronidases in humans: they are Hyal1, Hyal2, Hyal3, Hyal4, HyalPS1, and PH20/SPAM1. Human Hyal1 and Hyal2 are expressed in most of the tissues. PH20/SPAM1 (hereinafter referred to as PH20) is expressed in the sperm plasma membrane and the acrosomal membrane. However, HyalPS1 is not expressed because it is a pseudogene. Hyaluronidases are divided into, according to a method of cleaving hyaluronic acid, three types: enzymes (EC 3.2.1.35) that cleave β-1,4 bonds between N-acetylglucosamine and glucuronic acid by the use of H2O; enzymes (EC 3.2.1.36) that cleave β-1,3 bonds between N-acetylglucosamine and glucuronic acid by the use of H2O; and bacterial hyaluronidases (EC 4.2.99.1) that cleave β-1,4 bonds without using H2O.
The catalytic amino acids of Hyal1 are D129 and E131, which hydrolyze hyaluronic acid by substrate-assisted catalysis. Hyal1 exhibits the optimum activity at an acidic pH of 3 to 4, and has no enzymatic activity at pH 4.5 or higher. In contrast to Hyal1, PH20 exhibits enzymatic activity at a wide pH range of 3 to 8.
Arming et al. identified that the catalytic amino acids of PH20 are D111 and E113 (Arming et al., 1997). Arming et al. labelled Leu as the first amino acid of the mature protein, and thus the catalytic amino acids of the full-length PH20 with the signal peptide correspond to D146 and E148, respectively.
Hyaluronidase hydrolyzes hyaluronic acid, thereby reducing the viscosity of hyaluronic acid in the extracellular matrix and increasing the permeability thereof into tissue (skin). The subcutaneous area of the skin has a neutral pH of about 7.0 to 7.5. Thus, among the various types of hyaluronidases, PH20 is widely used in clinical practice (Bookbinder et al., 2006). In examples in which PH20 is used in clinical practice, PH20 is used as an eye relaxant and an anesthetic additive in ophthalmic surgery, and is also co-administered with an antibody therapeutic agent which is injected subcutaneously (Bookbinder et al., 2006). In addition, based on the property of hyaluronic acid that is overexpressed in tumor cells, PH20 is used to hydrolyze hyaluronic acid in the extracellular matrix of tumor cells, thereby increasing the access of an anticancer therapeutic agent to the tumor cells. In addition, it is also used to promote resorption of body fluids and blood, which are excessively present in tissue.
PH20 was first identified in guinea pig sperm by Lathrop et al., and is also known to be expressed in sperms of different species. Human PH20 gene was cloned by Lin et al. and Gmachl et al. Human PH20 has the amino acid sequence of SEQ ID NO: 1 which consists of 509 amino acid residues, and exhibits 60% amino acid identity with guinea pig PH20 gene. Human PH20 enzyme is encoded from SPAM1 (sperm adhesion molecule-1) gene, and Ser490 of PH20 is present as binding to the glycosylphosphatidylinositol (GPI) on the surface of the sperm plasma membrane and in the acrosomal membrane. Sperm hydrolyzes hyaluronic acid using PH20 when it penetrates oocytes through the hyaluronan-rich cumulus layer of the oocytes. PH20 is present in the amount corresponding to 1% or less of the amount of proteins in sperm, and has six N-glycosylation sites (N82, N166, N235, N254, N368, and N393).
Currently commercially available PH20 is obtained by extraction from the testes of cattle or sheep. Examples thereof include Amphadase® (bovine hyaluronidase) and Vitrase® (sheep hyaluronidase).
Bovine testicular hyaluronidase (BTH) is obtained by removing a signal peptide and 56 amino acids on the C-terminal from bovine wild-type PH20 during post-translational modification. BTH is also a glycoprotein, and has a mannose content of 5% and a glucosamine content of 2.2%, based on the total components including amino acids. When animal-derived hyaluronidase is repeatedly administered to the human body at a high dose, a neutralizing antibody can be produced. Since animal-derived hyaluronidase contains other biomaterials in addition to PH20, it may cause an allergic reaction when administered to the human body (Bookbinder et al., 2006). In particular, the production and the use of PH20 extracted from cattle can be limited due to concerns of mad cow disease. In order to overcome this problem, studies on the recombinant protein of human PH20 have been conducted.
Recombinant protein of human PH20 has been reported to be expressed in yeast (P. pastoris), DS-2 insect cells, and animal cells. The recombinant PH20 proteins produced in insect cells and yeast differ from human PH20 in terms of the pattern of N-glycosylation during post-translational modification.
Among hyaluronidases, only three dimensional structures of Hyal1 (PDB ID: 2PE4) (Chao et al., 2007) and bee venom hyaluronidase (PDB ID: 1FCQ, 1FCU, 1FCV) are determined. Hyal1 is composed of two domains, a catalytic domain and an EGF-like domain. The catalytic domain is in the form of (β/α)8 in which an alpha-helix and a beta-strand, which characterize the secondary structure of the protein, are each repeated eight times (Chao et al., 2007). The EGF-like domain is completely conserved in variants in which the C-terminus of Hyal1 is spliced differently. The amino acid sequences of Hyal1 and PH20 are 35.1% identical, and the protein structure of PH20 has not yet been found.
A recombinant protein of human PH20 was developed by Halozyme Therapeutic, Inc. and has been sold under the trade name Hylenex® (Bookbinder et al., 2006; Frost, 2007).
When D146 and E148, which are the catalytic amino acids of PH20, were mutated to asparagine (D146N) and glutamine (E148Q), respectively, there was no enzymatic activity (Arming et al., 1997). In addition, when R246 of PH20 was substituted with glycine, the enzymatic activity was reduced by 90%, and when E319 was substituted with glutamine and R322 was substituted with threonine, the enzymatic activity disappeared. A variant in which 36 amino acids at the C-terminus of PH20 were removed (474-509 amino-acid truncation) showed a 75% reduction in enzymatic activity compared to wild-type PH20. This variant was not secreted extracellularly and remained in HeLa cells. When C-terminal 134 amino acids were removed from PH20, PH20 had no enzymatic activity and was not secreted extracellularly. According to Frost et al., the C-terminal 477-483 region of PH20 is essential for soluble expression (Frost, 2007). The activity of full-length PH20 (1 to 509) or a PH20 variant having a C-terminus truncated at position 467 was merely 10% of a PH20 variant having a C-terminus truncated at one of positions 477 to 483 (Frost, 2007).
Meanwhile, recombinant PH20 still has insufficient thermal stability or expression levels in the recombinant cells. Therefore, there is a great demand in industry for a recombinant hyaluronidase having further improved biological and physico-chemical characteristics.
It is an object of the present invention to provide a hyaluronidase PH20 variant or fragment thereof which is improved in thermal stability, enzyme activity and expression level, compared to wild-type PH20, preferably mature wild-type PH20.
Another object of the present invention is to provide a composition for treating cancer, comprising the above-described hyaluronidase PH20 variant or fragment thereof, and a method of treating cancer using the same.
To achieve the above objects, the present invention provides a hyaluronidase PH20 variant or fragment thereof, which comprises one or more amino acid residue substitutions in the region corresponding to an alpha-helix region and/or its linker region in the amino acid sequence of wild-type PH20, preferably mature wild-type PH20, and in which one or more of the N-terminal or C-terminal amino acid residues are selectively deleted.
The present invention also provides a composition for treating cancer, comprising the above-described hyaluronidase PH20 variant or fragment thereof, and a method of treating cancer using the same.
Unless defined otherwise, all the technical and scientific terms used herein have the same meaning as those generally understood by one of ordinary skill in the art to which the invention pertains. Generally, the nomenclature used herein and the experiment methods, which will be described below, are those well-known and commonly employed in the art.
The present invention provides a hyaluronidase PH20 variant or fragment thereof, which comprises one or more amino acid residue substitutions in the region corresponding to an alpha-helix region and/or its linker region, preferably an alpha-helix 8 region (S347 to C381) and/or a linker region (A333 to R346) between alpha-helix 7 and alpha-helix 8, in the amino acid sequence of wild-type PH20, preferably mature wild-type PH20, and in which one or more of the N-terminal or C-terminal amino acid residues are selectively cleaved and deleted.
In the present invention, the positions of amino acid residues in each variant correspond to the amino acid positions of wild-type PH20 having the sequence of SEQ ID NO: 1.
In addition, in the present invention, “mature wild-type PH20” means a protein consisting of amino acid residues L36 to S490 of SEQ ID NO: 1, which lack M1 to T35, which form a signal peptide, and A491 to L509, which are not related to the substantial enzymatic function of PH20, in the amino acid sequence of wild-type PH20 having the sequence of SEQ ID NO: 1.
Specifically, the PH20 variant or fragment thereof according to the present invention may comprise one or more mutations, preferably amino acid residue substitutions selected from the group consisting of T341A, T341C, T341G, S343E, M345T, K349E, L353A, L354I, N356E and I361T, more preferably selected from the group consisting of T341A, T341C, L354I and N356E in wild-type PH20 having the amino acid sequence of SEQ ID NO: 1.
In the present invention, the term “PH20 variant” is intended to include mutation of one or more amino acid residues, preferably substitution of one or more amino acid residues in the amino acid sequence of wild-type PH20, as well as occurrence of deletion of one or more amino acid residues at N-terminus or C-terminus together with substitution of the amino acid residues, and is used as substantially the same meaning as the expression “PH20 variant or fragment thereof”.
In the present invention, the protein tertiary structure of PH20 located outside the active site was studied through the protein structure modeling of human PH20 on the basis of Hyal1 (SEQ ID NO: 2) which is a human hyaluronidase whose protein tertiary structure is known. As a result, amino acids located in the alpha-helix 8 region of PH20 were selected and substituted with the amino acid sequence of alpha-helix 8 of Hyal1, thereby attempting to enhance the thermal stability of the protein structure without affecting the catalytic activity of the enzyme. In particular, because alpha-helix 8 is located in the outer portion of the protein tertiary structure of PH20, there is less interaction with the adjacent alpha-helix or beta-strand than the other alpha-helices of PH20. According to the present invention, it has been found that when the amino acid sequence of the alpha-helix 8 region of human PH20 and a linker region between alpha-helix 7 and alpha-helix 8 is partially substituted with the amino acid sequence of the alpha-helix 8 region of highly hydrophilic Hyal1 and a linker region between alpha-helix 7 and alpha-helix 8 of Hyal1, the enzymatic activity at neutral pH and the protein aggregation temperature (Tagg.) increase. Based on these experimental results, it has been found that a novel PH20 variant or fragment thereof, which has increased enzymatic activity and thermal stability compared to wild-type PH20, can be provided.
Thus, the PH20 variant according to the present invention comprises one or more amino acid residue substitutions selected from the group consisting of T341A, T341C, T341G, S343E, M345T, K349E, L353A, L354I, N356E and I361T, preferably selected from the group consisting of T341A, T341C, L354I and N356E in the amino acid sequence of wild-type PH20 (having the amino acid sequence of SEQ ID NO: 1), preferably mature wild-type PH20 (having a sequence consisting of amino acid residues L36 to S490 in the amino acid sequence of SEQ ID NO: 1).
The PH20 variant according to the present invention also comprises one or more amino acid residue substitutions in the region corresponding to an alpha-helix region and/or its linker region, preferably an alpha-helix 8 region (S347 to C381) and/or the linker region (A333 to R346) between alpha-helix 7 and alpha-helix 8, more preferably T341 to N363, T341 to I361, L342 to I361, S343 to I361, I344 to I361, M345 to I361, or M345 to N363 in wild-type PH20 having the amino acid sequence of SEQ ID NO: 1.
In particular, in the PH20 variant according to the present invention, the alpha-helix 8 region (S347 to C381) and/or the linker region (A333 to R346) between alpha-helix 7 and alpha-helix 8 of the wild-type PH20, preferably the mature wild-type PH20 may be substituted with one or more amino acid residues of the corresponding region (see Tables 2 and 3) of Hyal1 having the sequence of SEQ ID NO: 2, but is not limited thereto.
P56~D65
P163~R194
S317~G332
P299~G314
S347~C381
More specifically, the novel PH20 variant or fragment thereof according to the present invention preferably comprises an amino acid residue substitution of L354I and/or N356E in the amino acid sequence of wild-type PH20, preferably mature wild-type PH20,
and further comprises at least the amino acid residue substitution at one or more positions selected from among T341 to N363, particularly one or more positions selected from the group consisting of T341, L342, S343, I344, M345, S347, M348, K349, L352, L353, D355, E359, I361 and N363, but is not limited thereto.
More preferably, the amino acid residue substitution at one or more positions selected from the group consisting of T341, L342, S343, I344, M345, S347, M348, K349, L352, L353, D355, E359, I361 and N363 may be one or more amino acid residue substitutions selected from the group consisting of T341A, T341C, T341D, T341G, T341S, L342W, S343E, I344N, M345T, S347T, M348K, K349E, L352Q, L353A, D355K, E359D, I361T and N363G, but is not limited thereto.
Preferably, the novel PH20 variant or fragment thereof according to the present invention may comprise one or more amino acid residue substitutions selected from the group consisting of M345T, S347T, M348K, K349E, L352Q, L353A, L354I, D355K, N356E, E359D and I361T,
and may further comprise one or more amino acid residue substitutions selected from the group consisting of T341A, T341C, T341D, T341G, T341S, L342W, S343E, I344N and N363G, but is not limited thereto.
More preferably, the novel PH20 variant or fragment thereof according to the present invention may comprise any one amino acid residue substitution selected from the following amino acid residue substitution groups, but is not limited thereto:
(a) T341S, L342W, S343E, I344N, M345T, S347T, M348K, K349E, L352Q, L353A, L354I, D355K, N356E, E359D and I361T;
(b) L342W, S343E, I344N, M345T, S347T, M348K, K349E, L352Q, L353A, L354I, D355K, N356E, E359D and I361T;
(c) M345T, S347T, M348K, K349E, L352Q, L353A, L354I, D355K, N356E, E359D, I361T and N363G;
(d) T341G, L342W, S343E, I344N, M345T, S347T, M348K, K349E, L352Q, L353A, L354I, D355K, N356E, E359D and I361T;
(e) T341A, L342W, S343E, I344N, M345T, S347T, M348K, K349E, L352Q, L353A, L354I, D355K, N356E, E359D and I361T;
(f) T341C, L342W, S343E, I344N, M345T, S347T, M348K, K349E, L352Q, L353A, L354I, D355K, N356E, E359D and I361T;
(g) T341D, L342W, S343E, I344N, M345T, S347T, M348K, K349E, L352Q, L353A, L354I, D355K, N356E, E359D and I361T;
(h) I344N, M345T, S347T, M348K, K349E, L352Q, L353A, L354I, D355K, N356E, E359D and I361T; and
(i) S343E, I344N, M345T, S347T, M348K, K349E, L352Q, L353A, L354I, D355K, N356E, E359D and I361T.
In the present invention, an expression described by one-letter amino acid residue code together with numbers, such as “S347”, means the amino acid residue at each position in the amino acid sequence of SEQ ID NO: 1.
For example, “S347” means that the amino acid residue at position 347 in the amino acid sequence of SEQ ID NO: 1 is serine.
In addition, “S347T” means that serine at position 347 of SEQ ID NO: 1 is substituted with threonine.
The PH20 variant according to the present invention is interpreted as including variants or fragments thereof in which the amino acid residue at the specific amino acid residue position is conservatively substituted.
As used herein, the term “conservative substitution” refers to modifications of a PH20 variant that involves the substitution of one or more amino acids for amino acids having similar biochemical properties that do not result in loss of the biological or biochemical function of the PH20 variant.
A “conservative amino acid substitution” is one in which the amino acid residue is replaced with an amino acid residue having a similar side chain. Families of amino acid residues having similar side chains have been defined and are well known in the art to which the present invention pertains. These families include amino acids with basic side chains (e.g., lysine, arginine and histidine), amino acids with acidic side chains (e.g., aspartic acid and glutamic acid), amino acids with uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, and cysteine), amino acids with nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, and tryptophan), amino acids with beta-branched side chains (e.g., threonine, valine, and isoleucine), and amino acids with aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, and histidine).
It is envisioned that the PH20 variant or fragments thereof of the present invention may still retain the activity although it has conservative amino acid substitutions.
In addition, the PH20 variant or fragment thereof according to the present invention is interpreted to include PH20 variants or fragments thereof having substantially the same function and/or effect with those/that of the PH20 variant or fragment thereof according to the present invention, and having an amino acid sequence homology of at least 80% or 85%, preferably at least 90%, more preferably at least 95%, most preferably at least 99% to the PH20 variant or fragment thereof according to the present invention.
The PH20 variants according to the present invention have increased expression levels and protein refolding rate, thereby increasing high thermal stability, compared to mature wild-type PH20. Furthermore, the enzymatic activity of the PH20 variants was more increased than or similar to that of mature wild-type PH20 despite an increase in the thermal stability.
Meanwhile, even if the mature wild type PH20 variants with the C-terminal deletion showed the decrease in enzymatic activities, based on the present invention, the C-terminal deleted PH20 variants showed the similar or increased enzymatic activities due to the more rapid protein refolding and thermal stabilities. In addition, PH20 variants in this present invention maintained the enzymatic activities when the N-terminal amino acids were deleted up to five amino acid residues. This indicated that for the protein expression and enzyme activities P41 of the N-terminus was important.
Accordingly, the PH20 variant or fragment thereof according to the present invention is characterized in that it comprises one or more amino acid residue substitutions in the alpha-helix 8 region (S347 to C381) and/or the linker region (A333 to R346) between alpha-helix 7 and alpha-helix 8 in the amino acid sequence of wild-type PH20, and one or more of the N-terminal and/or C-terminal amino acid residues are additionally deleted, but is not limited thereto.
In one aspect, the PH20 variant or fragment thereof according to the present invention may be one in which cleavage occurs before an amino acid residue selected from the group consisting of M1 to P42 of the amino acid sequence of SEQ ID NO: 1, preferably before an amino acid residue L36, N37, F38, R39, A40, P41, or P42 at the N-terminus, so that one or more amino acid residues at the N-terminus are deleted, and/or cleavage occurs after an amino acid residue selected from the group consisting of V455 to L509, preferably after an amino acid residue selected from the group consisting of V455 to S490, most preferably after an amino acid residue V455, C458, D461, C464, I465, D466, A467, F468, K470, P471, P472, M473, E474, T475, E476, P478, I480, Y482, A484, P486, T488, or S490 at the C-terminus, so that one or more amino acid residues at the C-terminus are deleted.
The expression “cleavage occurs before an amino acid residue selected from the group consisting of M1 to P42 at the N-terminus” means that an amino acid residue immediately before an amino acid residue selected from among M1 to P42 at the N-terminus is cleaved and deleted.
For example, the expression “cleavage occurs before an amino acid residue L36, N37, F38, R39, A40, P41, or P42” respectively means that all amino acid residues from M1 to T35 immediately before L36, all amino acid residues from M1 to L36 immediately before N37, all amino acid residues from M1 to N37 immediately before F38, all amino acid residues from M1 to F38 immediately before R39, all amino acid residues from M1 to R39 immediately before A40, all amino acid residues from M1 to A40 immediately before P41, or all amino acid residues from M1 to P41 immediately before P42 in the amino acid sequence of SEQ ID NO: 1 is cleaved and removed, respectively.
In addition, the expression “cleavage occurs after an amino acid residue selected from the group consisting of V455 to L509 at the C-terminus” means that an amino acid residue immediately after an amino acid residue selected from among V455 to L509 at the C-terminus is cleaved and deleted.
For example, the expression “cleavage occurs after an amino acid residue V455, C458, D461, C464, I465, D466, A467, F468, K470, P471, P472, M473, E474, T475, E476, P478, I480, Y482, A484, P486, T488 or S490 at the C-terminus” means that an amino acid residue after the amino acid residue V455, C458, D461, C464, I465, D466, A467, F468, K470, P471, P472, M473, E474, T475, E476, P478, I480, Y482, A484, P486, T488 or S490 in the amino acid sequence of SEQ ID NO: 1 is cleaved and removed.
Preferably, the novel PH20 variant or fragment thereof according to the present invention may be selected from the group consisting of amino acid sequences of SEQ ID NOs: 60 to 115, but is not limited thereto.
Most preferably, the novel PH20 variant or fragment thereof according to the present invention may have the amino acid sequence of SEQ ID NO: 99. The novel PH20 variant or fragment thereof having an amino acid sequence of SEQ ID NO: 99 may comprise 15 amino acid substitutions of T341S, L342W, S343E, I344N, M345T, S347T, M348K, K349E, L352Q, L353A, L354I, D355K, N356E, E359D and I361T, and deletion before F38 at the N-terminus, and truncation after F468 at the C-terminus.
The sequences of the substituted or cleaved amino acids in the PH20 variants constructed in the specific embodiment according to the present invention are as shown in Table 11.
A study focused on increasing the enzymatic activity and thermal stability of PH20 by amino acid substitution of an alpha-helix and its linker region, which are secondary structures forming the tertiary structure of the protein, as disclosed in the present invention, has not been previously reported. Previous studies reported that the enzymatic activity of wild-type PH20 changes depending on the cleavage positions of amino acid residues located at the C-terminal region. However, in the present invention, a specific alpha-helix forming the secondary structure of PH20 was substituted with the alpha-helix of other human hyaluronidase, thereby constructing PH20 variants having higher stability than wild-type PH20. These variants may be variants in which the interaction of the substituted alpha-helix domain with portions forming other secondary structures of PH20 shows a pattern different from that of wild-type PH20, indicating that the variants have consistent enzymatic activity regardless of the C-terminal cleavage position.
In specific embodiment, the novel PH20 variant or fragment thereof according to the present invention, which has increased enzymatic activity and thermal stability compared to mature wild-type PH20, may be one which comprises one or more amino acid residue substitutions selected from the group consisting of T341A, T341C, T341G, S343E, M345T, K349E, L353A, L354I, N356E and I361T, and in which one or more amino acids located in an alpha-helix 8 region (S347 to C381) and/or the linker region (A333 to R346) between alpha-helix 7 and alpha-helix 8 in the amino acid sequence of wild-type PH20, preferably mature wild-type PH20, are substituted with other amino acids.
Specifically, the amino acid substitution in the linker region between alpha-helix 7 and alpha-helix 8 comprises the substitution of one or more amino acid residues in the region consisting of amino acid residues T341 to N363, T341 to I361, L342 to I361, L342 to I361, S343 to I361, I344 to I361, M345 to I361, or M345 to N363.
In order to examine the effect of C-terminal truncation in PH20 variants in which alpha-helix 8 and a linker region between alpha-helix 7 and alpha-helix 8 are substituted, three PH20 variants (HM6, HM10 and HM21) were selected as templates.
HM6 is a variant in which amino acids in M345 to N363 region are substituted with the amino acid sequence of Hyal1 (M345T, S347T, M348K, K349E, L352Q, L353A, L354I, D355K, N356E, E359D and I361T in SEQ ID NO: 1 are substituted). In addition, HM6 is a variant in which the substitution of alpha-helix 8 and a linker region between alpha-helix 7 and alpha-helix 8 is the least substituted variant among the PH20 variants according to the present invention, which do not comprise additional C-terminal cleavage (that is, a form in which the C-terminal amino acid residue is S490, like mature wild-type PH20).
HM10 is a variant in which amino acids in L342 to I361 region are substituted with the amino acid sequence of Hyal1 (L342W, S343E, I344N, M345T, S347T, M348K, K349E, L352Q, L353A, L354I, D355K, N356E, E359D and I361T in SEQ ID NO: 1 are substituted), and which has the highest thermal stability while having an enzymatic activity similar to that of mature wild-type PH20 among the PH20 variants according to the present invention, which do not comprise additional C-terminal truncation.
HM21 is a variant in which amino acids in T341 to I361 region are substituted with the amino acid sequence of Hyal1 (T341S, L342W, S343E, I344N, M345T, S347T, M348K, K349E, L352Q, L353A, L354I, D355K, N356E, E359D and I361T in SEQ ID NO: 1 are substituted), and which has an enzymatic activity which is about two times higher than that of wild-type PH20 at pH 7.0 among the PH20 variants according to the present invention, which do not comprise additional C-terminal truncation.
The HM6-based PH20 variants constructed in the present invention have the N-terminus starting at L36 and the C-terminus terminating at I465, F468, or P471 as shown in Table 4 below.
The HM10-based PH20 variants commonly have the N-terminus cleaved before the F38 residue and the C-terminus cleaved after the V455, C458, D461, C464, I465, D466, A467, F468, K470, P472, M473, E474, T475, E476, P478, I480, Y482, A484, P486, or T488 residue as shown in Table 5 below.
As shown in the examples of variants which comprise amino acid substitutions in the L342 to I361 region corresponding to the alpha-helix 8 region and the linker region between alpha-helix 7 and alpha-helix 8 of HM10 as a template and in which the N-terminus was cleaved before the F38 residue and the C-terminus was cleaved at I465, D466, A467, F468, K470, P472, M473, E474, T475, E476, P478, I480, Y482, A484, P486, or T488, the PH20 variants according to the present invention exhibited an enzymatic activity similar to that of mature wild-type PH20 regardless of the C-terminal cleavage position.
As shown in Table 6 below, two HM21-based PH20 variants commonly have the N-terminus cleaved before the F38 residue and the C-terminus cleaved after the F468 or K470 residue.
Variants were constructed using, as a template, HM21 having an enzymatic activity which is about two times higher than that of mature wild-type PH20. These variants are those which comprise amino acid substitutions in the T341 to I361 region corresponding to the alpha-helix 8 region and the linker region between alpha helix 7 and alpha-helix 8 and in which the N-terminus was cleaved before the F38 residue and the C-terminus was cleaved after F468 or K470. Surprisingly, these variants maintained the high enzymatic activity of HM21 regardless of the C-terminal cleavage position.
In the study conducted by Frost et al., when the length of PH20 is shorter due to the cleavage before the amino acid position of 477, the enzymatic activity decreased to about 10% of a variant having a C-terminus cleaved after the position 477. However, in the present invention, when one or more amino acids in alpha-helix 8 of PH20 and its linker region were substituted, the enzymatic activity was maintained due to the increase in the stability of the protein regardless of the C-terminal cleavage position. This result is very significant in that it solves the problem that the enzymatic activity of wild-type PH20 is reduced due to the C-terminal truncation of wild-type PH20.
In addition, in the present invention, the effect of the N-terminal amino acids of PH20, which has not been known previously, was studied.
In order to examine the effects of N-terminal cleavage sites in HM6 variants in which one or more amino acid residues in the region (M345 to I361) corresponding to the alpha-helix region of wild-type PH20 and the linker region between alpha-helix 7 and alpha-helix 8 (substituted with M345T, S347T, M348K, K349E, L352Q, L353A, L354I, D355K, N356E, E359D or I361T in SEQ ID NO: 1 and comprising no additional C-terminal cleavage) were substituted with amino acid residues of the corresponding alpha-helix 8 region of Hyal1 and the linker region between alpha-helix 7 and alpha-helix 8, variants, in which amino acid residues L36 to V47 in SEQ ID NO: 1 were substituted with FRGPLLPNR or amino acid residues L36 to A52 in SEQ ID NO: 1 were substituted with FRGPLLPNRPFTTV, were constructed using HM6 as a template. In addition, using HM6 as a template, the variants HM40, HM13, HM41, HM24, HM42 and HM25 were constructed in which the N-terminus in the amino acid sequence of SEQ ID NO: 1 was cleaved before the N37, F38, R39, A40, P41 or P42 residue (see Table 7).
As a result, it was shown that when the N-terminus of HM6 was cleaved before the N37, F38, R39, A40 or P41 residue, the enzymatic activity was not greatly influenced; however, when the N-terminus was cleaved before the P42 residue, the enzymatic activity significantly decreased, indicating that the N-terminal region of PH20, located after P41, is important for protein expression and enzymatic activity. In addition, when one or more amino acids in the N-terminal L36 to V47 or L36 to A52 region of HM6 were substituted with the amino acids of Hyal1, the variant protein was not expressed in ExpiCHO cells, indicating that the N-terminal region is important for protein expression.
In addition, in the present invention, it was attempted to increase the expression of a recombinant PH20 protein in animal cells by using the signal peptide of other proteins, instead of using the original signal peptide of PH20.
Therefore, in another aspect, the novel PH20 variant according to the present invention may be one in which the N-terminus further comprises a human growth hormone signal peptide having an amino acid sequence MATGSRTSLLLAFGLLCLPWLQEGSA of SEQ ID NO: 3, a human serum albumin signal peptide having an amino acid sequence MKWVTFISLLFLFSSAYS of SEQ ID NO: 4, or a human Hyal1 signal peptide having an amino acid sequence MAAHLLPICALFLTLLDMAQG of SEQ ID NO: 5 as shown in Table 8 below, instead of the signal peptide of wild-type PH20, which consists of M1 to T35, but is not limited thereto.
The expression “instead of the signal peptide of wild-type PH20, which consists of M1 to T35” means a case in which the signal peptide of wild-type PH20 is partially or completely deleted; thus it does not perform its function. In addition, the expression is meant to include a case in which a portion of the N-terminus is further deleted, for example, a case in which cleavage occurs before the N37, F38, R39, A40, P41 or P42 residue occurs so that an additional deletion of the N-terminus together with the deletion of the signal peptide of wild-type PH20 occurs.
In another aspect, the present invention provides a composition for treating cancer comprising the novel PH20 variant according to the present invention, and a method for treating cancer using the same.
Cancers or carcinomas that can be treated by the novel PH20 variant according to the present invention are not limited particularly, but includes both solid cancers and blood cancers. The cancer may be selected from the group consisting of liver cancer, hepatocellular carcinoma, gastric cancer, breast cancer, lung cancer, ovarian cancer, bronchial cancer, nasopharyngeal cancer, laryngeal cancer, pancreatic cancer, bladder cancer, colorectal cancer, colon cancer, uterine cervical cancer, brain cancer, prostate cancer, bone cancer, thyroid cancer, parathyroid cancer, renal cancer, esophageal cancer, biliary tract cancer, testis cancer, rectal cancer, head and neck cancer, ureteral cancer, osteosarcoma, neurocytoma, fibrosarcoma, rhabdomyosarcoma, astrocytoma, neuroblastoma and neuroglioma, but is not limited thereto. Preferably, cancers that can be treated by the composition according to the present invention may be selected from the group consisting of colorectal cancer, breast cancer, lung cancer and renal cancer, but is not limited thereto.
The composition of the present invention may be a pharmaceutical composition. The pharmaceutical composition may further comprise a pharmaceutically acceptable component. The component that is typically used in the formulation of drugs may be one or more selected from the group consisting of, but not limited to, lactose, dextrose, sucrose, sorbitol, mannitol, starch, gum acacia, calcium phosphate, alginate, gelatin, calcium silicate, microcrystalline cellulose, polyvinylpyrrolidone, cellulose, water, syrups, methyl cellulose, methylhydroxybenzoate, propylhydroxybenzoate, talc, magnesium stearate, and mineral oil. In addition, the pharmaceutical composition may further comprise one or more selected from the group consisting of diluents, excipients, lubricants, wetting agents, sweeteners, aromatics, emulsifiers, suspensions, and preservatives.
The pharmaceutical composition of the present invention may be administered orally or parenterally. The parenteral administration is carried out by intravenous injection, subcutaneous injection, intramuscular injection, intraperitoneal injection, endothelial administration, topical administration, intranasal administration, intrapulmonary administration, rectal administration, and the like. For the oral administration, the active ingredient in the composition needs to be formulated into a coated dosage form or into a dosage form which can protect the active ingredient from being disintegrated in stomach considering that peptides and proteins are digested in stomach. Alternatively, the present composition may be administered via any device by which the active ingredient can move to the target cell of interest.
The pharmaceutical composition may be formulated in the form of solutions, suspensions, syrups or emulsions in oils or aqueous media, or in the form of extracts, grains, suppositories, powders, granules, tablets or capsules, and may additionally include dispersing or stabilizing agents for the purpose of formulation.
In particular, the composition for treating cancer according to the present invention may be used for combined treatment with other anticancer drugs.
An anticancer drug that can be used for combined treatment with the novel PH20 variant according to the present invention is preferably a chemical anticancer drug, an antibody-based anticancer drug, a biological anticancer drug, an RNAi, or a cell therapeutic agent, but is not limited thereto.
Preferably, the anticancer drug that can be used for combined treatment with the novel PH20 variant according to the present invention is preferably an immuno-oncologic agent, more preferably an immune checkpoint inhibitor, but is not limited thereto.
In another aspect, the present invention is directed to a nucleic acid encoding the PH20 variant or fragment thereof.
The nucleic acids, as used herein, may be present in cells, in the cell lysate, or in the partially purified or substantially pure form. “Isolated” or “substantially pure”, when referring to nucleic acids, refer to those that have been purified away from other cellular components or other contaminants, e.g., other cellular nucleic acids or proteins, by standard techniques, including alkaline/SDS treatment, CsCl banding, column chromatography, agarose gel electrophoresis, and others well known in the art. The nucleic acids of the present invention may be DNA or RNA.
In still another aspect, the present invention is directed to recombinant expression vector comprising the nucleic acid. For expression of the PH20 variant or fragment thereof according to the present invention, a DNA encoding the PH20 variant can be obtained by standard molecular biology techniques (e.g., PCR amplification or cDNA cloning using a hybridoma that expresses the PH20 variant), and the DNA can be inserted into an expression vector such that it is “operatively linked” to transcriptional and translational control sequences.
As used herein, the term “operatively linked” is intended to mean that a gene encoding the PH20 variant or fragment thereof is ligated into a vector such that transcriptional and translational control sequences serve their intended function of regulating the transcription and translation of the gene encoding the PH20 variant or fragment thereof. The expression vector and expression control sequences are chosen to be compatible with the expression host cell used. The genes encoding the PH20 are inserted into the expression vector by standard methods (e.g., ligation of complementary restriction enzyme sites on a fragment of the gene encoding the PH20 variant or fragment thereof and vector, or blunt end ligation if no restriction enzyme sites are present).
In addition, the recombinant expression vectors carry regulatory sequences that control the expression of a gene encoding the PH20 variant in the host cell. The term “regulatory sequence” is intended to include promoters, enhancers and other expression control elements (e.g., polyadenylation signals) that control the transcription or translation of the genes encoding the PH20 variant or fragment thereof. It will be appreciated by those skilled in the art that the design of the expression vector, including the selection of regulatory sequences, may depend on such factors as the choice of the host cell to be transformed, the level of expression of protein desired, etc.
In yet another aspect, the present invention is directed to a host cell comprising the nucleic acid or the vector. The host cell according to the present invention is preferably selected from the group consisting of animal cells, plant cells, yeasts, E. coli., and insect cells, but is not limited thereto.
Specifically, the host cell according to the present invention include prokaryotic cells such as E. coli, Bacillus subtilis, Streptomyces sp., Pseudomonas sp., Proteus mirabilis or Staphylococcus sp., fungi such as Aspergillus sp., yeasts such as Pichia pastoris, Saccharomyces cerevisiae, Schizosaccharomyces sp. and Neurospora crassa, and eukaryotic cells such as lower eukaryotic cells, and higher other eukaryotic cells such as insect cells.
In addition, the host cells that can be used in the present invention may be derived from plants or mammals. Preferably, examples of the host cells include, but are not limited to, monkey kidney cells (COS7), NSO cells, SP2/0, Chinese hamster ovary (CHO) cells, W138, baby hamster kidney (BHK) cells, MDCK, myeloma cells, HuT 78 cells and HEK293 cells. More preferably, CHO cells may be used.
The nucleic acid or the vector is transfected into a host cell. Transfection can be performed using various techniques that are generally used to introduce foreign nucleic acid (DNA or RNA) into prokaryotic or eukaryotic cells, for example, electrophoresis, calcium phosphate precipitation, DEAE-dextran transfection or lipofection. In order to express the PH20 variant or fragment thereof of the present invention, various combinations of recombinant expression vectors and host cells can be employed. The preferred expression vector for eukaryotic cells comprises gene expression regulatory sequences derived from, but not limited to, SV40, bovine papillomavirus, adenovirus, adeno-associated virus, cytomegalovirus and retrovirus. The expression vector, which can be used for bacterial hosts, comprises bacterial plasmids, such as, pET, pRSET, pBluescript, pGEX2T, pUC vector, col E1, pCR1, pBR322, pMB9 and the derivatives thereof, obtained from E. coli; a plasmid having broad host range, such as, RP4; phage DNAs exemplified by various phage lambda derivatives, such as, λgt10, λgt11 and NM989; and other DNA phages, such as, M13 and filamentous single-stranded DNA phage. The expression vector available for yeast cells may be 2-μm plasmid and its derivatives. The expression vector for insect cells includes pVL941.
In a further aspect, the present invention is directed to a method for producing an PH20 variant or fragment thereof, the method comprising a step of culturing the host cell and expressing the PH20 variant or fragment thereof according to the present invention.
When a recombinant expression vector capable of expressing the PH20 variant or fragment thereof is introduced into mammalian host cells, the PH20 variant or fragment thereof can be produced by culturing the host cells for a period of time such that the PH20 variant or fragment thereof is expressed in the host cells, preferably a period of time such that the PH20 variant is secreted into the medium during culture of the host cells.
In some cases, the expressed PH20 variant can be isolated and purified from the host cells. Isolation or purification of the PH20 variant can be performed by conventional isolation/purification methods (e.g., chromatography) that are used for proteins. The chromatography may include one or more combinations selected from affinity chromatography, ion exchange chromatography, and hydrophobic chromatography, but is not limited thereto. In addition to the chromatography, a combination of filtration, ultrafiltration, salting out, dialysis, and the like may be used to isolate and purify the antibody.
Hereinafter, the present invention will be described in further detail with reference to examples. It will be obvious to a person having ordinary skill in the art that these examples are illustrative purposes only and are not to be construed to limit or change the scope of the present invention.
For construction of PH20 variants, the cDNA (clone ID: hMU002604) of wild-type PH20 was purchased from the Korean Human Gene Bank. Wild-type PH20 encodes amino acids from L36 to S490. The PH20 gene was amplified by polymerase chain reaction (hereinafter referred to as PCR) and inserted into the XhoI and NotI restriction enzyme sites of a pcDNA3.4-TOPO vector. For expression in ExpiCHO cells, the signal peptide of human growth hormone, human serum hormone or human Hyal1 was used as a signal peptide instead of the original signal peptide of PH20. For protein purification using a HisTrap column, the DNA sequence of a 6×His-tag was located at the 3′-end of the PH20 cDNA. The amino acid substitution of PH20 variants was performed using PCR method, and the amino acid substitution was confirmed by DNA sequencing.
The list of primers used in cloning of the PH20 variants are summarized in Table 9 below, and the specific sequences of the primers are summarized in Table 10 below.
After finding the PH20 variant with increased enzymatic activity and thermal stability, the 6×His-tag-free cDNA of the PH20 variant was also constructed.
When the cell density of ExpiCHO cells reached 6×106/mL, a plasmid comprising the wild-type or variant PH20 cDNA inserted in the pcDNA3.4-TOPO vector was transfected into the ExpiCHO cells by ExpiFectamine CHO reagent. As a cell culture medium, ExpiCHO expression medium (100 to 500 mL) was used. After transfection, the ExpiCHO cells were shake-cultured at 130 rpm for total 6 days, during which the cells were cultured at 37° C. for 1 day and further cultured at lower temperature of 32° C. for 5 days. After completion of the culture, the cell supernatant was collected by centrifugation at 10,000 rpm for 30 min.
The recombinant proteins of the C-terminal 6×His-attached wild-type PH20 and variant PH20, produced in the ExpiCHO cells, were purified in three steps (performed using a HisTrap column, a Q Sepharose column and a Phenyl column, respectively) by an AKTA prime system.
For protein purification using the HisTrap column, buffer A (20 mM sodium phosphate, pH 7.5, 0.5 M NaCl) and buffer B (20 mM sodium phosphate, pH 7.5, 0.5 M NaCl, 0.5 M imidazole) were prepared. The protein was bound to the HisTrap column, and the column was flushed with 5 column volumes (CV) of buffer A to remove non-specifically bound proteins. It was confirmed that the conductivity was maintained at constant level, the column was flushed with 5 CV of 20% buffer B to elute the protein. The eluted protein was dialyzed with dialysis buffer (20 mM sodium phosphate, pH 7.5, 50 mM NaCl). For protein purification using the Q Sepharose column, buffer A (20 mM sodium phosphate, pH 7.5) and buffer B (20 mM sodium phosphate, pH 7.5, 0.5 M NaCl) were prepared. The protein was bound to the Q Sepharose column, and the column was flushed with 5 CV of buffer A to remove nonspecifically bound proteins, and then 5 CV of buffer B was flushed at concentration gradient of 0 to 100% to elute the protein.
For protein purification using the phenyl column, buffer A (20 mM sodium phosphate, pH 7.0, 1.5 M (NH4)2SO4) and buffer B (20 mM sodium phosphate, pH 7.0) were prepared. The protein was bound to the phenyl column, and the column was flushed with 5 CV of buffer A to remove nonspecifically bound proteins, and then 5 CV of buffer B was flushed at concentration gradient of 0 to 100% to elute the protein.
The enzymatic activities of wild-type PH20 and variant PH20 were measured by turbidimetric assay, substrate-gel assay, and Morgan-Elson assay.
The turbidimetric assay is a method of measuring the absorbance in the precipitate produced when hyaluronic acid is mixed with albumin (BSA). When hyaluronic acid is hydrolyzed by PH20, the absorbance of the precipitate produced when mixed with albumin decreases. Hyaluronidase PH20 (Sigma) was diluted to 1, 2, 5, 7.5, 10, 15, 20, 30, 50 and 60 units/mL, and prepared in each tube. The purified protein sample was dissolved in enzyme diluent buffer (20 mM Tris.HCl, pH 7.0, 77 mM NaCl, 0.01% (w/v) bovine serum albumin) and diluted to 100×, 300×, 600×, 1200× and 2400× and prepared in each tube. In fresh tubes, the hyaluronic acid solution having a concentration of 3 mg/mL was diluted 10-fold to a concentration of 0.3 mg/mL so that the volume of each tube became 180 μL. 60 μL of enzyme was added to and mixed with the diluted hyaluronic acid solution and allowed to react at 37° C. for 45 min. After completion of the reaction, 50 μL of the reacted enzyme and 250 μL of acidic albumin solution were added to each well of a 96-well plate and shaken for 10 min, and then the absorbance was measured at 600 nm by spectrophotometer.
In the substrate-gel assay, the protein was electrophoresed on 10% SDS gel (including 0.17 mg/mL hyaluronic acid) for 1 h, and SDS was removed with 2.5% Triton X-100 (w/v) at 4° C. for 2 h. Thereafter, an enzymatic reaction was performed in the buffer (50 mM sodium phosphate, pH 7.0, 150 mM NaCl) at 37° C. (which is the optimum temperature for PH20) for 1 to 4 h, and the protein was stained with 0.5% Alcian blue reagent. Alcian blue reagent not bound to the hyaluronic acid was removed using de-staining solution. The SDS gel stained with Alcian blue was imaged, and then the band was quantified.
The thermal stability of the protein was measured by a method of measuring the aggregation temperature by dynamic light scattering (DLS), a method of measuring the melting temperature (Tm) in real-time PCR using Sypro-Orange dye, a method of measuring the enzymatic activity after leaving the protein to stand at predetermined temperature for a predetermined time, etc. In the method of measuring the aggregation temperature by DLS, the aggregation of molecules is measured using light scattering, and thus the sensitivity is high and the aggregation temperature is generally lower than the melting temperature of the protein.
The sequences of the substituted or cleaved amino acids in the PH20 variants constructed in the present invention are shown in Table 11 below.
Among the variants according to the present invention, the variant having the 6×His-tag attached to the C-terminus of PH20 was named HM; the variant free of the 6×His-tag was named HP; mature PH20 (L36 to S490) having the 6×His-tag attached to the C-terminus was named WT; and mature wild-type PH20 (L36 to Y482) having the C-terminus cleaved after Y482 while being free of the 6×His-tag was named HW2.
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In order to construct variants having higher enzymatic activity and thermal stability than WT by substituting amino acids located in the alpha-helix 8 region of PH20 and the linker region between alpha-helix 7 and alpha-helix 8, the following variants were constructed: the variant HM1 in which amino acids in the M345 to N363 region were substituted; the variant HM2 in which 7 amino acids in the Y365 to V379 region were substituted; and the variant HM3 in which 19 amino acids in the M345 to V379 region were substituted. Among the amino acids located in alpha-helix 8 of PH20, C351, which is involved in disulfide bonding, and Y357 which is involved in hydrophobic interaction, were not substituted. The substituted amino acid sequences in the variants HM1, HM2 and HM3 are shown in Table 11 above. When ExpiCHO cells were transfected with the pcDNA3.4-TOPO plasmid comprising the gene of the variant HM1, HM2 or HM3, the variant HM1 was expressed in the ExpiCHO cells (
The variant HM6 was expressed in ExpiCHO cells, and the expression level thereof was similar to that of the variant HM1 (the expression level was 3.4-fold higher than that of WT) (
When the thermal stabilities of WT and the variants HM1 and HM6 were compared based on the aggregation temperatures, the aggregation temperatures were 46.5° C., 53.0° C. and 50.5° C., respectively, indicating that the aggregation temperatures of the variants HM1 and HM6 were 6.5° C. and 4.0° C. higher, than that of WT, respectively (
In addition, when the hydrophilic/hydrophobic natures of WT and the variants HM1 and HM6 were compared using a phenyl column chromatography, HM1 and HM6 were all eluted earlier than WT. This suggests that the variants HM1 and HM6 have a more hydrophilic nature than WT due to the substitution of the amino acids. However, the variants HM1 and HM6 eluted from the phenyl column showed two peaks, unlike WT, and exhibited the same molecular weight when treated with PNGase F. This appears to be a difference caused by N-glycosylation (
It is believed that the amino acid substitution of the M345 to N363 and M345 to I361 regions by construction of the variants HM1 and HM6 in Example 2 resulted in an increase in both the enzymatic activity and thermal stability of PH20, has made great advances in terms of protein engineering. Thus, based on the variants HM1 and HM6, other amino acids in the N-terminal and C-terminal directions were additionally substituted.
First, the variants HM4 and HM7 were constructed, which comprise the substituted amino acids in the variants HM1 and HM6 and in which the amino acids between G340 and I344 were additionally substituted with G340V, T341S, L342W, S343E and I344N. The sequences of the substituted amino acid sequences in the variants HM4 and HM7 are shown in Table 11 above. The variants HM4 and HM7 were expressed in ExpiCHO cells. The results of protein purification for HM7 are shown in
The difference between the variants HM6 and HM7 is amino acids between G340 and I344. In order to identify amino acids which are involved in the increased thermal stability of the variant HM7, the following variants were constructed based on the variant HM6: HM8 in which I344N was substituted; HM9 in which S343 and I344N were substituted; HM10 in which L342W, S343E and I344N were substituted; and HM21 in which T341S, L342W, S343E and I344N were substituted. The sequences of the substituted amino acids in the variants HM8, HM9, HM10 and HM21 are shown in Table 11 above. The variants HM8, HM9, HM10 and HM21 were expressed in ExpiCHO cells (
When the physical properties of the variants HM7, HM8, HM9, HM10 and HM21 were examined using a phenyl column chromatography, these PH20 variants were eluted earlier than WT, suggesting that these variants all have a hydrophilic nature. However, the pattern of the main peak at the amino acid substitution position appeared differently (
The variant HM7 also showed two peaks in the phenyl column chromatography, like the variants HM1 and HM6, suggesting that two different types were present.
In order to examine the patterns of migration of WT and the variants depending on their isoelectric points, isoelectric focusing (hereinafter referred to as IEF) analysis was performed (
In addition, based on the variant HM6, other amino acids in the C-terminal regions of alpha-helix 8 were substituted, thereby constructing the variants HM11 and HM12. The sequences of the substituted amino acids in the variants HM11 and HM12 are shown in Table 11 above. The variant HM11 was expressed in ExpiCHO cells, but the expression level thereof was lower than that of WT (
The C-terminal region of PH20 is already well known to play an important role in the expression and enzymatic activity of PH20, but the role of the N-terminal region of PH20 is not well known. In order to examine the effect of cleavage of the amino acid at the N-terminal region of PH20 on the enzymatic activity, variants HM40, HM13, HM41, HM24, HM42 and HM25 having the N-terminus cleaved at N37, F38, R39, A40, P41 or P42 were constructed based on the variant HM6 (Table 11). Furthermore, HP61 and HP62 with modifications at the N-terminal amino acids were additionally constructed.
The variants HM40, HM13, HM41, HM24, HM42, HP61 and HP62 were expressed in ExpiCHO cells, but HM25 was not expressed (
Regarding the enzymatic activities of the N-terminal cleaved PH20 variants, measured by the substrate-gel assay (1 h of reaction), the enzymatic activities of HM40, HM13 and HM41 were similar to that of the HM6 variant, but the enzymatic activities of HM24 and HM42 were lower than that of HM6 (
When the physical properties of the variants HM40, HM13, HM41, HM24 and HM42 were analyzed using a phenyl column chromatography, these variants were eluted from the column earlier than WT, suggesting that these variants have a hydrophilic nature (
The aggregation temperatures of the N-terminal cleaved PH20 variants, measured by DLS, were different among the variants depending on the position where the amino acid started (
The C-terminal region of PH20 is known to play an important role in protein expression and enzymatic activity. In the present invention, the variants HM14, HM15 and HM16, in which the C-terminal amino acids were cleaved at I465, F468 and K471, respectively, were constructed based on the variant HM6. The sequences of the substituted amino acids in these variants HM14, HM15 and HM16 are shown in Table 11 above. These variants HM14, HM15 and HM16 were expressed in ExpiCHO cells (
The structural flexibilities of WT and the variants HM14, HM15 and HM16 were examined by fluorescence quenching using acrylamide (
The enzymatic activities of the variants HM14, HM15 and HM16, measured by turbidimetric assay, were also confirmed in substrate-gel assay (
When the physical properties of the C-terminal cleaved variants were analyzed using a phenyl column chromatography, the variants HM14, HM15 and HM16 were all eluted earlier than WT, indicating that they had a hydrophilic nature. In addition, the hydrophobicities of these variants were in the order of HM16>HM14>HM15 (
The PH20 variants constructed in the present invention were based on HM6, and HM8, HM9 and HM10, in which amino acid residues G340 to I344 were additionally substituted, exhibited better performance than WT in terms of protein expression levels, enzymatic activities and thermal stabilities. The variants HM19 and HM20 were constructed which had an N-terminus cleaved at F38 and a C-terminus cleaved at F468 based on HM10 having high enzymatic activity and thermal stability among variants HM8, HM9 and HM10. HM19 and HM20 were all expressed in ExpiCHO cells and purified using a HisTrap column chromatography (
The expression levels of HM10-based C-terminal truncated variants in ExpiCHO cells showed a tendency to decrease as the length of the C-terminal region became shorter, and these variants were not expressed when the C-terminus was truncated at C464 or shorter (
In order to examine whether the variant is not expressed in ExpiCHO cells when the C-terminus is cleaved at residue 464 or shorter, Western blot analysis was performed. As shown in
The enzymatic activities of the HM10-based C-terminal truncated variants, measured by turbidimetric assay, are shown in
When the enzymatic activities of the HM10-based C-terminal truncated variants were measured by substrate-gel assay, these variants exhibited higher enzymatic activity than WT, and showed enzymatic activity similar to that of the template HM10, indicating that the difference in enzymatic activity depending on the length of the C-terminal region was not significant (
The variant HP34 was purified by four-step column chromatography (
In turbidimetric assay, the activities of HP34 and HP46 were 45.6 U/μg and 47.2 U/μg, respectively, which were about 2-fold higher than that of WT and were about 10% higher than that of the template HM21 (
The kinetics of each variant was measured by Morgan-Elson assay, and the results of the measurement are shown in
The aggregation temperatures of HP34 and HP46, measured by DLS, were 51.5° C. and 51.0° C., respectively, which were similar to that of the template HM21 and were about 5° C. higher than that of HW2, indicating that these variants were thermally stable (
Wild-type HW2 and the variant HP46 were left to stand overnight at pH 7.0 and pH 3.0, and then the enzymatic activities thereof were compared by substrate-gel assay. As a result, it was shown that HP46 exhibited high activity not only at pH 7.0 but also at pH 3.0, indicating that it had excellent stability (
HM53, HM54, HM55, HM56, HP59 and HP60 are variants having a mutation at the amino acid at position 341, among HM21-based variants. It was confirmed that the mutation of the amino acid at position 341 had various effects on the expression level and activity of the variants (
Biopharmaceuticals with higher molecular weights than those of low-molecular-weight synthetic chemicals have a risk of triggering unintended immune responses when they enter the human body. An outside contact surface, created by folding or interaction with adjacent domains in the secondary structure or tertiary structure of a large-molecular-weight biomaterial, can promote immune response to the biomaterial by providing an epitope to the immune system in the human body. This immune response can produce an anti-drug antibody (ADA), and this response can inhibit the drug's effectiveness, or cause hypersensitivity to the drug, or promote clearance of the drug in the human body. The immune response to the drug may therefore affect the results in clinical trials, and may cause serious abnormal reactions upon long-term use. This immune response can be influenced by various factors, and triggered by the specific response to the drug itself or disease, or by factors that depend on the method of drug administration or individual patients. Factors caused by the drug itself include the similarity or dissimilarity of the biopharmaceuticals to human peptides, posttranslational modification, impurities, aggregate formation, and the characteristics of the formulation. Factors that varies among individual patients include sex, reactivity with other drugs being taken, and genetic factors depending on the type of human leukocyte antigen (HLA).
This immunogenic response is triggered by CD4+ T cells or CD8+ T cells that recognize epitopes regardless of the cause of the immune response. Because of HLA class II gene diversity in individuals, epitopes of CD4+ T cells are different among individuals, and therefore the responsiveness to biopharmaceuticals in CD4+ T cells in each blood provided by the healthy donor can be a very important criterion for evaluating immune responses that may arise in clinical processes. CD4+ T cells are activated by antigen presenting cells (APCs) recognizing the antigens presented through their type II MHC (major histocompatibility complex). Activated CD4+ T cells release cytokines that activate macrophages, cytotoxic T cells, and B cells, resulting in high levels of antibody production. On the contrary, CD8+ T cells have direct cytotoxicity and directly remove cells infected with antigens, damaged cells, or cells that lost their function. CD8+ T cells have T cell receptors that can recognize specific antigen peptides bound to type I MHC molecules located on the surface of every cell. CD8+ T cells can also be activated by recognizing antigens presented by antigen presenting cells, and this activation can be further enhanced by cytokines of CD4+ T cells. Therefore, when the activation level of CD4+ T cells and CD8+ T cells by new biomaterials is measured in vitro, it is possible to predict immunogenic responses that can be induced in clinical processes. In this example, in order to predict the immunogenicity of the PH20 variant in comparison with a control, CD4+ T cells and CD8+ T cells were isolated from PBMCs, and then treated with 1.5 ng/mL and 15 ng/mL of the control PH20 and the PH20 variant (HP46), and then the distributions of activated CD4+ T cells and CD8+ T cells were measured. The activation level of each type of T cells was measured using Stimulating Index, and Stimulating Index (SI) is defined as follows:
Stimulating Index (SI)=(T-cell activation level after treatment with test sample)/(T-cell activation level after treatment with vehicle)
If the SI value of cells is 2 or more, it can be determined that the cells were activated at the significant level.
Immunogenic responses may vary depending on the HLA type. Therefore, experiments for measuring responses in more various HLA types were performed using T cells isolated from PBMCs provided from 10 healthy donors. The HLA types of the 10 PBMCs used are shown in Table 12 below.
The results of measuring the activation levels of CD4+ and CD8+ T cells treated with each of PH20 and the PH20 variant are summarized in Table 13 below. When looking at the results of measuring the activation levels of CD4+ and CD8+ T cells, it appears that PH20 and the PH20 variant all show relatively low activation levels. In the case of PH20, the activation level of CD4+ T cells was measured to be 2 or more in two experiments, and in the case of the PH20 variant, the activation of CD4+ T cells was not detected. In the case of PH20, the activation of CD8+ T cells was detected in one experiment, and in the case of the PH20 variant, the activation of CD8+ T cells was also detected in one experiment. However, in the case of PH20, the SI value was measured to be 2 or more at both 1.5 ng/mL and 15 ng/mL, but in the case of the PH20 variant, an SI value of 2 or less at 1.5 ng/mL and an SI value of 2 or more at 15 ng/mL were measured (see
Therefore, at the lower concentration, the activation level of CD8+ T cells was observed to be low in the case of the PH20 variant, and it is determined that the activation level of CD8+ T cells by PH20 is higher than the activation level of CD8+ T cells by the PH20 variant. The conclusions drawn from the above results are as follows:
1) the activation levels of CD4+ T cells and CD8+ T cells by PH20 and the PH20 variant are relatively low; and
2) the possibility of activation of CD4+ T cells and CD8+ T cells by the PH20 variant is lower than that by PH20.
From these results, it is expected that the PH20 variant will have a lower possibility of triggering an immunogenic response in clinical processes than PH20.
The PH20 variants or fragments thereof according to the present invention have increased protein expression levels and show an increase in protein aggregation temperature of 4-11.5° C. or so when expressed in CHO (ExpiCHO) cells so that they can be efficiently produced while having high thermal stability, compared to the mature wild-type PH20.
Further, as the result of substrate-gel assay, one of tests to measure the activity of hyaluronidase, the PH20 variants or fragments thereof according to the present invention have improved protein refolding so that they are re-natured faster than that of the mature wild-type PH20, and the original enzymatic activity is maintained regardless of the C-terminal cleavage position.
Furthermore, the PH20 variants or fragments thereof according to the present invention have low immunogenicity so that they can be repeatedly administered to the human body.
The electronic file is attached.
Number | Date | Country | Kind |
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10-2018-0086308 | Jul 2018 | KR | national |
10-2019-0029758 | Mar 2019 | KR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/KR2019/009215 | 7/25/2019 | WO | 00 |