Site News  |   Monitor Keywords  |   Monitor Archive  |   Organizer  |   Account Info  |

Rational evolution of cytokines for higher stability, the cytokines and encoding nucleic acid molecules

This application is a divisional of U.S. application Ser. No. 10/658,834, entitled, “RATIONAL EVOLUTION OF CYTOKINES FOR HIGHER STABILITY, THE CYTOKINES AND ENCODING NUCLEIC ACID MOLECULES,” filed Sep. 8, 2003, which claims the benefit of priority under 35 U.S.C. 119(e) to U.S. provisional application Ser. No. 60/457,135, entitled “RATIONAL EVOLUTION OF CYTOKINES FOR HIGHER STABILITY, ENCODING NUCLEIC ACID MOLECULES AND RELATED APPLICATIONS,” filed Mar. 21, 2003, and U.S. provisional application Ser. No. 60/409,898, entitled “RATIONAL EVOLUTION OF CYTOKINES FOR HIGHER STABILITY, ENCODING NUCLEIC ACID MOLECULES AND RELATED APPLICATIONS,” filed Sep. 9, 2002, each to Rene Gantier, Thierry Guyon, Manuel Vega and Lila Drittanti.

This application is related to U.S. application Ser. No. 11/176,830, filed Jul. 6, 2005, which is also a continuation of U.S. application Ser. No. 10/658,834, filed Sep. 8, 2003. This application is also related to PCT Application No. PCT/IB03/004347, entitled, “RATIONAL EVOLUTION OF CYTOKINES FOR HIGHER STABILITY, THE CYTOKINES AND ENCODING NUCLEIC ACID MOLECULES,” to Rene Gantier, Thierry Guyon, Manuel Vega and Lila Drittanti. This application also is related to U.S. application Ser. No. 10/658,355, filed Sep. 8, 2003, entitled “RATIONAL DIRECTED PROTEIN EVOLUTION USING TWO-DIMENSIONAL RATIONAL MUTAGENESIS SCANNING,” and to U.S. provisional application Ser. No. 60/457,063, entitled “RATIONAL DIRECTED PROTEIN EVOLUTION USING TWO-DIMENSIONAL RATIONAL MUTAGENESIS SCANNING,” filed Mar. 21, 2003, and to U.S. provisional application Ser. No. 60/410,258, entitled “RATIONAL DIRECTED PROTEIN EVOLUTION USING TWO-DIMENSIONAL RATIONAL MUTAGENESIS SCANNING,” filed Sep. 9, 2002, each to Rene Gantier, Thierry Guyon, Hugo Cruz Ramos, Manuel Vega and Lila Drittanti. This application also is related to co-pending U.S. application Ser. No. 10/022,249, filed Dec. 17, 2001, entitled “HIGH THROUGHPUT DIRECTED EVOLUTION BY RATIONAL MUTAGENESIS,” to Manuel Vega and Lila Drittanti.

The subject matter of each of the above-noted applications, international applications and provisional applications is incorporated by reference in its entirety.

An electronic version on compact disc (CD-R) of the Sequence Listing is filed herewith in duplicate (labeled Copy # 1 and Copy # 2), the contents of which are incorporated by reference in their entirety. The computer-readable file on each of the aforementioned compact discs, created on Feb. 1, 2007 is identical, 1,843 kilobytes in size, and titled 922DSEQ.001.txt.

Modified cytokine proteins having selected modified properties compared to the unmodified or wild type proteins, and nucleic acid molecules encoding these proteins are provided. The proteins can be used for treatment and diagnosis.

The delivery of therapeutic proteins for clinical use is a major challenge to pharmaceutical science. Once in the blood stream, these proteins are constantly eliminated from circulation within a short time by different physiological processes, involving metabolism as well as clearance using normal pathways for protein elimination, such as (glomerular) filtration in the kidneys or proteolysis in blood. The latter is often the limiting process affecting the half-life of proteins used as therapeutic agents in per-oral administration and either intravenous or intramuscular injection. The problems associated with these routes of administration of proteins are well known and various strategies have been used in attempts to solve them.

A protein family, which has been the focus of much clinical work, and efforts to improve its administration and bio-assimilation, is the cytokine family, including the interferon family. Interferon molecules are grouped in the heterogeneous family of cytokines, originally identified on the basis of their ability to induce cellular resistance to viral infections (Diaz et al., J. Interferon Cytokine Res., 16:179-180, 1996). Type I interferons, referred to as interferons α/β, include many members of the interferon α family (interferon α1, α2, ω and τ) as well as interferon β. The type II interferon γ is different from type I in its particular mechanisms that regulate its production. Whereas the production of interferons α/β is most efficiently induced in many types of cells upon viral infection, interferon-γ is produced mainly in cells of hemopoietic system, such as T-cells or natural killer cells, upon stimulation by antigens or cytokines, respectively. These two interferon systems are functionally non-redundant in the antiviral defense host.

Interferon α, hereinafter “interferon alpha-2b,” or “interferon α-2b” or “IFNα-2b,” used interchangeably, has a broad spectrum of biological effects, including antiviral effects. Antiviral effects include antiproliferative and immuno-modulatory actions (Stark et al., Annu. Rev. Biochem., 67: 227-264, 1998). As well as eliciting strong antiviral activities in target cells, interferons α/β also activate effector cells of the innate immune system such as natural killer cells and macrophages (Pestka et al., Annu. Rev. Biochem., 56: 727-777, 1987; Biron et al., Annu. Rev. Immunol., 17:189-220, 1999). As part of its immuno-modulatory action, interferon type I protects T-lymphocytes from apoptosis (Scheel-Toeller et al., Eur. J. Immunol., 29:2603-2612, 1999; Marrack et al., J. Exp. Med., 189:521-530, 1999) and growth enhancing factors (Robert et al., Hematol. Oncol., 4:113-120, 1986; Morikawa et al., J. Immunol., 139:761-766, 1987). The biological effects of interferons α/β are initiated upon binding to the IFN type I receptor, which results in activation of several downstream effector molecules (Hibbert and Foster, J. Interferon Cytokine Res., 19:309-318, 1999).

Interferons as well as many cytokines are important therapeutics. Since naturally occurring variants have not evolved as therapeutics, they often have undesirable side-effects as well as the above-noted problems of short-half life, administration and bioavailability. Hence, there is a need to improve properties of cytokines, including interferons, for use as therapeutic agents. Therefore, among the objects herein, it is an object to provide cytokines that have improved therapeutic properties.

Provided herein are methods for directed evolution of families of proteins and resulting families of modified proteins. A family, such as the cytokine protein family, is initially identified. A property or phenotype for modification, such as resistance to proteolysis for increased stability in blood, is selected for modification. A representative member or members of the family, such as members of the interferon α family, such as IFNα-2b or IFNα-2a, or interferon β family, is (are) selected. It is modified using any directed evolution method and protein(s) with a desired phenotype are screened and identified. In addition, the 3-dimensional structure of the protein can be mapped to topologically and spatially identify the loci that are modified to achieve the phenotypic change. 3-dimensional structures of other members of the family are generated or obtained and compared with the modified family member. Loci in the other family members that correspond on the protein to those modified in the original protein are identified and modified. The resulting proteins can be tested to confirm that they exhibit the modified phenotype.

Provided herein are methods for generating modified cytokines based on structural homology (3D scanning). These methods are based on the spatial and topological structure; they are not based on their underlying sequences of amino acid residues. The methods are used for identification of target sites for mutagenesis, particularly in families of target proteins. The targets are identified through comparison of patterns of protein backbone folding between and among structurally related proteins. The methods are exemplified herein for cytokines. Families of the modified cytokines also are provided herein.

Any protein known or otherwise available to those of skill in the art is suitable for modification, such as optimization or improvement of a selected property, using the directed evolution methods provided herein, including cytokines (e.g., IFNα, including IFNα-2b and IFNα-2a, and IFNβ) or any other proteins that have already been mutated or optimized.

Provided herein are modified cytokines that exhibit increased resistance to proteolysis as assessed in vivo or in vitro. Typically the increase in resistance is a least 5%, generally 8%, 10% or more. The modified cytokines provided herein include those designed by 3D scanning using the interferon α's that were modified based upon 2D scanning methods herein.

Also provided herein are modified (mutant) cytokine proteins, such as variants of IFNβ and IFNα, including IFNα-2b and IFNα-2a proteins and IFNβ proteins, that have altered, particularly, improved therapeutic properties, including higher stability compared to the unmodified forms. In particular, exemplary modified cytokines provided herein have increased stability, which, for example, improves their use as therapeutics. Among the modified cytokines provided herein are those that exhibit increased resistance to proteolysis compared to the unmodified cytokine. In particular, such resistance is at least 10%, 20%, 30%, 40%, 50%, 70%, 100% or more resistant to proteolysis compared to the unmodified cytokine. Also provided are cytokines that have increased anti-proliferative and/or antiviral activity and/or resistance to proteolysis compared to an unmodified cytokine.

Exemplary of the modified cytokines provided herein are modified interferons that exhibit higher stability compared to unmodified forms. Such modified interferons can be used for treating conditions in humans that are responsive to treatment with interferons, such, but are not limited to, as viral infections, cancer or tumors, undesired cell proliferation and for immuno-modulation.

Exemplary of proteins that can be modified by the 2D and 3D scanning methods provided herein are cytokines from the interferons/interleukin-10 family. This family includes, for example, interleukin-10 (IL-10; SEQ ID NO:200, interferon beta (IFNβ; SEQ ID NO: 196), interferon alpha-2a (IFNα-2a; SEQ ID NO: 182), interferon alpha-2b (IFNα-2b; SEQ ID NO:1), and interferon gamma (IFN-γ; SEQ ID NO: 199). The long-chain cytokine protein family includes, among others, granulocyte colony stimulating factor (G-CSF; SEQ ID NO: 210), leukemia inhibitory factor (LIF; SEQ ID NO: 213), growth hormone (hGH; SEQ ID NO: 216), ciliary neurotrophic factor (CNTF; SEQ ID NO: 212), leptin (SEQ ID NO: 211), oncostatin M (SEQ ID NO: 214), interleukin-6 (IL-6; SEQ ID NO: 217) and interleukin-12 (IL-12; SEQ ID NO: 215). The short-chain cytokine protein family includes, among others, erythropoietin (EPO; SEQ ID NO: 201), granulocyte-macrophage colony stimulating factor (GM-CSF; SEQ ID NO: 202), interleukin-2 (IL-2; SEQ ID NO: 204), interleukin-3 (IL-3; SEQ ID NO: 205), interleukin-4 (IL-4; SEQ ID NO: 207), interleukin-5 (IL-5; SEQ ID NO: 208), interleukin-13 (IL-13; SEQ ID NO: 209), Flt3 ligand (SEQ ID NO: 203) and stem cell factor (SCF; SEQ ID NO: 206). Modified forms of each that have increased resistance to proteolysis are provided. They were generated by comparison among the 3D-structures to identify residues that improve resistance to proteolysis.