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Title:
RIBOSOMAL S-6 KINASE (RSK) INHIBITORY PEPTIDES AND METHOD OF USE THEREOF
Document Type and Number:
WIPO Patent Application WO/2008/150282
Kind Code:
A1
Abstract:
The present invention provides ribosomal S-6 Kinase (RSK) inhibitory peptides, and methods of use thereof, for the prevention and treatment of cirrhosis. The RSK inhibitory peptides preferably comprise a CCAAT/Enhancer Binding Protein-β subunit (C/EBPβ) mutant comprising an Alanine substitution at position 217 of the native C/EBPβ.

Inventors:
BUCK, Martina (935 Jeffrey Road, Del Mar, CA, 92014, US)
Application Number:
US2007/062700
Publication Date:
December 11, 2008
Filing Date:
February 23, 2007
Export Citation:
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Assignee:
UNIVERSITY OF CALIFORNIA, SAN DIEGO (9500 Gilman Drive, Mc0910La Jolla, CA, 92093-0910, US)
BUCK, Martina (935 Jeffrey Road, Del Mar, CA, 92014, US)
International Classes:
A61K38/03; A61K38/07; A61K38/16
Other References:
BUCK M. ET AL.: 'C/EBPbeta Phosphorylation by RSK Creates a Functional XEXD Caspase Inhibitory Box Critical for Cell Survival' MOLECULAR CELL vol. 8, no. 4, 2001, pages 807 - 816, XP001157557
BUCK M. ET AL.: 'A Ribosomal S-6 Kinase-Mediated Signal to C/EBP-beta Is Critical for the Development of Liver Fibrosis' PLOS ONE vol. 2, no. 12, 2007, page E1372
Attorney, Agent or Firm:
WARREN, William, L. et al. (Sutherland Asbill & Brennan LLP, 999 Peachtree Street N, Atlanta GA, 30309-3996, US)
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Claims:

CLAIMS

What is claimed is:

I. An isolated peptide for preventing or treating cirrhosis comprising a human ribosomal S-6 kinase (RSK) inhibitory peptide.

2. The isolated peptide of Claim 1, wherein said RSK inhibitory peptide comprises a CCAAT/Enhancer Binding Protein-β subunit (C/EBPβ) mutant comprising an Alanine substitution at position 217 of a native C/EBPβ.

3. The isolated peptide of Claim 2, wherein said C/EBPβ mutant comprises an amino acid sequence as set forth in SEQ ID NO: 1.

4. The isolated peptide of Claim 2, wherein said C/EBPβ mutant comprises an amino acid sequence as set forth in SEQ ID NO:2.

5. An isolated nucleotide encoding the RSK inhibitory peptide of Claim 1.

6. A pharmaceutical composition for preventing or treating cirrhosis comprising the RSK inhibitory peptide of Claim 1, and a pharmaceutically acceptable carrier.

7. The pharmaceutical composition of Claim 6, wherein said RSK inhibitory peptide comprises a CCAAT/Enhancer Binding Protein-β subunit (C/EBPβ) mutant comprising an Alanine substitution at position 217 of a native C/EBPβ.

8. The pharmaceutical composition of Claim 7, wherein said C/EBPβ mutant comprises an amino acid sequence as set forth in SEQ ID NO: L

9. The pharmaceutical composition of Claim 7, wherein said C/EBPβ mutant comprises an amino acid sequence as set forth in SEQ ID NO:2.

10. An antibody generated from a peptide comprising the RSK inhibitory peptide of Claim 1.

I I . A method of preventing or treating cirrhosis comprising administering to a subject in need an effective amount of a pharmaceutical composition comprising a human ribosomal S-6 kinase (RSK) inhibitory peptide. .

12. The method of Claim 11, wherein said RSK inhibitory peptide comprises a CCAAT/Enhancer Binding Protein-β subunit (C/EBPβ) mutant comprising an Alanine substitution at position 217 of a native C/EBPβ,

23. The method of Claim 12, wherein said C/EBPβ mutant comprises an amino acid sequence as set forth in SEQ ID NO: 1.

24. The method of Claim 12, wherein said C/EBPβ mutant comprises an amino acid sequence as set forth in SEQ ϊD NO:2,

Description:

RIBOSOMAL S-6 KINASE (RSK) INHIBITORY PEPTIDES AND METHOD

OF USE THEREOF

STATEMENT OF GOVERNMENT INTEREST

10001] This invention was supported by the U.S. Department of Veterans Affairs and the Federal Government has certain rights in this invention.

REFERENCE TO RELATED APPLICATIONS

[0002J This application claims the priority benefit of U.S. provisional patent application Ser. No. 60/776, 1 19. "'Assays and Treatments for Virus Infections and Other Disease Conditions, " ' filed February 23, 2006 and the entire application is incorporated by reference herewith.

FIELD OF THE INVENTION

[0003] The invention relates to liver fibrosis and cirrhosis. In particular, the present invention relates to ribosomal S-6 kinase (RSK) inhibitory peptides, and method of use thereof, for preventing and treating liver cirrhosis.

BACKGROUND OF THE INVENTION

|00041 The annual worldwide mortality from liver cirrhosis is approximately 800,000 (Reducing Risks, Promoting Healthy Life In T he World Health Report 2002 1-230 (World Health Organization, Geneva, 2002)), and there is no available treatment (Report 04-5491 Executive Summary in Action Plan for Liver Disease Research 1-6 (NIH, U.S. Department of Health and Human Services, 2004)), Excessive tissue repair in chronic liver diseases induced by viral, toxic, immunologic, and metabolic disorders (Chung, R. & Podolsky, D. Cirrhosis and its Complications in Harrison's Principles of Internal Medicine 1754-1767 (McGraw-Hill, New York, 2005)), results in the deposition of scar tissue and the development of cirrhosis (Chojkier, M., Regulation of collagen gene expression in Liver growth and repair (eds. Strain, A. & Diehl, A.) 430-450 (Chapman & Hall, London, 1998)).

[00051 Quiescent hepatic stellate cells (HSC) produce negligible amounts of extracellular matrix proteins (ECM), but after their activation, these cells develop a

myofibroblastic phenotype, proliferate and become the main contributors of ECM (Buck, M, et al., MoI. Cell 4, 1087-1092 (1999); Lee, K. S. et al., J. Clin. Invest. 96, 2461-2468 (1995)). This step is required for the development of liver fibrosis and cirrhosis (Friedman, S. L., J. Biol. Chem, 275, 2247-2250 (2000); Bataller, R. et at, J. Clin. Invest. 115, 209-218 (2005); Ankoma-Sey, V. & Friedman, S. Hepatic stellate cells in Liver growth and repair (eds. Strain, A. & Diehl, A.) 512-537 (Chapman & Hall, London, 1998)).

[0006] In response to liver injury, hepatic stellate cell activation causes excessive liver fibrosis resulting in cirrhosis (Chojkier, M, Regulation of collagen gene expression in Liver growth and repair (eds. Strain,A. & Diehl,A.) 430-450 (Chapman & Hall, London, 1998); Friedman, S. L. J. Biol. Chem. 275, 2247-2250 (2000); Batatler, R. et al., J. Clin. Invest. 1 15, 209-218 (2005)). Phosphorylation of the CCAAT/Enhancer Binding Protein-β (C/EBPβ) on threonine-217 (T217) by ribosomal-S-6 kinase (RSK) is indispensable for the activation and survival of these cells (Buck, M. et al., MoL Cell 8, 807-816 (2001)).

[0007| The mitogen -activated protein kinase (MAPK) pathway, through the extracellular signal-regulated kinase (ERK 1/2), activates RSK (Buck, M. et al, MoI. Cell 8, 807-816 (2001); Bonni, A. et al. Science 286, 1358-1362 (1999); Bhatt, R. et al., Science 286, 1362-1365 (1999); Gross, S. et al., Science 286, 1365-1367 (1999); Sassone-Corsi, P. et al., Science 285, 886-891 (1999)), resulting in the phosphorylation of mouse C/EBPβ on T217 (Buck, M. et al, MoI. Cell 8, 807-816 (2001); Buck, M. et al., MoI. Cell 4, 1087-1092 (1999)). This phosphorylation of C/EBPβ is evolutionary conserved and necessary for HSC survival upon their activation (Buck, M. el al., MoI. Cell 8, 807-816 (2001)). It has been known that the RSK pathway may be critical for HSC activation induced by liver injury, because expression of a catalytically inactive mutant RSK (Nakajima, T. et al., Cell 86, 465-474 (1996)), blocked proliferation and survival of cultured HSC upon their activation by collagen type 1 (Buck, M, et al., MoI. CeIl S, 807-816 (2001)).

|0008] Activation of stellate cells is responsible for the development of liver cirrhosis in chronic liver diseases of all causes (Chojkier, M. et al.. Regulation of collagen gene expression in Liver growth and repair (eds. Strain,A. & Diehl,A.) 430-450

(Chapman & Hall, London, 1998); Bataller, R. et al., J. Clin. Invest. 115, 209-218

(2005); Chung, R. & Podolsky, D. Cirrhosis and its Complications in Harrison's Principles of Internal Medicine 1754-1767 (McGraw-Hill, New York, 2005)) and remarkably, HSC clearance by apoptosis may allow recovery from liver injury and reversal of liver fibrosis (Iredaie, J. et ai, Semin. Liv. Dis. 21, 427-436 (2001)).

[0009] Therefore, for the treatment for liver diseases, there is a need to develop a therapeutic strategy for the prevention and treatment of cirrhosis by inhibition of the RSK pathway. Based on the findings that the RSK-C/EBPβ phosphorylation pathway is critical for the development of liver cirrhosis, the discovery of the present invention satisfies the need by providing small molecules inhibiting RSK-C/EBPβ phosphorylation and methods for the regression of liver fibrosis, and further prevention of development of primary iiver cancer.

SUMMARY OF THE INVENTION

10010] The present invention provides ribosomal S-6 kinase (RSK) inhibitory compounds, preferably peptides, or analogs thereof, for preventing or treating liver cirrhosis. In preferred embodiments, the RSK inhibitory peptide is a CCAAT/Enhancer Binding Protein-β subunit (C/EBPβ) mutant comprising an Alanine substitution at position 217 of the native C/EBPβ. In another preferred embodiment, the RSK inhibitory peptide is a C/EBPβ mutant comprising an amino acid sequence of KAVD (SEQ ID NO: 1) (C/EBPβ-A217). In yet another preferred embodiment, the RSK inhibitory peptide comprising an amino acid sequence of KAVDKLSDEYKMRRERNN1AVRKSRDKAKMRNLETQHK (SEQ ID NO:2) (C/EBPβ216-253-A217). The RSK inhibitory peptides of the present invention are believed to prevent and/or induce regression of liver fibrosis or cirrhosis by inhibiting RSK-C/EBPβ phosphoylation pathway, resulting in activation of capase 8 activity, and inducing apoptosis of hepatocyte stellate cells (HSC).

[0011] The present invention also provides isolated nucleotides encoding the aforementioned RSK inhibitory compounds, peptides, mutants, or analogs thereof.

[0012] The present invention further provides antibodies generated from the RSK inhibitory compounds, peptides, mutants, or analogs thereof, for preventing and/or treating liver fibrosis or cirrhosis. The present invention also provides vaccines

comprising the RSK inhibitory compounds, peptides, mutants, or analogs thereof, for preventing liver fibrosis or cirrhosis. Pharmaceutical compositions for preventing and/or treating liver fibrosis or cirrhosis comprising the aforementioned RSK inhibitory peptides, mutants, analogs, antibodies, and vaccine thereof, and one or more pharmaceutically acceptable carrier, are also provided.

[0013J Furthermore, the present invention provides methods for preventing or treating liver fibrosis or cirrhosis comprising administering to a subject in need an effective amount of pharmaceutical composition comprising the aforementioned RSK inhibitory compounds, peptides, mutants, analogs, antibodies, vaccines thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 illustrates that C/EBPO-A217 mice are refractory to the induction of liver fibrosis. C/EBPβ +/+ [wt]. C/EBPβ-A217 and C/EBPβ "7" [ko] mice received weekly i.p. injections of CCU or mineral oil (control) for 12 weeks. Fig. Ia. Representative Mallory's trichrome stain for liver fibrosis (in blue; arrowheads). Alt C/EBPβ +/+ (wt) mice (n= \2) developed liver cirrhosis. The C/EBPβ-A2I7 f«=12; PO.0001) and C/EBPβ " ' " [ko] (π=6; P<0.01) mice had either no fibrosis or only minimal liver fibrosis. Fig. Ib. Representative Sinus red immunohistochemistry for collagen (in red; arrowhead). Marked increase in liver collagen in a cirrhotic pattern was observed in C/EBPβ +/+ , but not in C/EBPβ-A 217 or C/EBPβ " ' " [ko], mice. Fig. Ic. Analysis of hepatic collagen content by Sirius red, showed a ~3-foId increase in C/EBPβ" "/í mice treated with CCl 4 (O= 12), compared to C/EBPβ-A217 mice treated with CCl 4 fn=12 ; PO.001). C/EBPβ v~ mice were also refractory to the induction of liver fibrosis by CCl 4 (n= 6; P<0.01).

10015] Figure 2 illustrates that C/EBPβ-A217 mice have less liver collagen after CCl 4 treatment. Representative confocal microscopy for collagen type 1 (in red) using specific antibodies. Marked increase in liver collagen type 1 in a cirrhotic pattern was observed in C/EBPβ +/ " [wt], but not in C/EBPβ-A217 or C/EBPβ v" [ko], mice after chronic CCl 4 treatment.

100161 Figure 3 illustrates that C/EBPβ-A217 mice are refractory to hepatic stellate cell activation and proliferation. Mice received CCU or mineral oil injections for 12 weeks

as described in Fig 1. Fig. 3a. Activated stellate cells, identified by confocal microscopy for α-smooth muscle actin (cc-SMA; red), displayed C/EBPβ-PhosphoT217 (green) in livers of C/EBPβ +/+ [wt], but not C/EBPβ-A217, mice treated with CCl 4 . Colocalization of ct-SMA and C/EBPβPhosphoT217 is shown in yellow (merge). Nuclei are identified with TO-PRO-3 (blue). Only background staining was observed when omitting the first antibody. Fig. 3b. Proliferating cell nuclear antigen (PCNA; red) was present in activated stellate cells only in livers of C/EBPβ +/+ [wt] mice treated with CCl 4 , while active caspase 3 (green) was found in stellate cells only in livers of C/EBPβ-A217 mice treated with CCl 4 . Nuclei are identified with TO-PRO-3 (blue).

[0017] Figure 4 illustrates that C/EBPβ-A217 inhibits RSK activation in hepatic stellate cells. Fig. 4a. A phospho-RSK immunoblot was performed on RSK imniunoprecipitates from protein lysates of purified HSC in an experiment conducted as described in Fig. 1. Phosphorylated RSK [RSKp380] was decreased in HSC isolated from C/EBPβ-A2I7 mice. C/EBPβ and RSK were similar in the different experimental groups. β-Actin was used as an internal control for the immunoprecipitations. Results from triplicate samples of three independent experiments are shown. Fig. 4b. A caspase 8 immunoblot was performed on C/EBPβ immunoprecipitates from protein lysates from samples described in (Fig. 4a). The association between C/EBPβ-A217 with active caspase 8 was increased in HSC isolated from C/EBPβ-A217 mice. Phosphorylated C/EBPβ-T217 was decreased in HSC from C/EBPPA217 mice treated with CCI 4 . C/EBPβ and RSK were similar in the different experimental groups. β-Actin was used as an internal control for the immunoprecipitations. Fig. 4c. Primary C/EBPβ +/+ HSC were transfected with vectors (1 μg each) expressing green fluorescent protein with control wt RSK (GFP), a dominant negative RSK mutant, or C/EBPβ- A217. Transfected stellate cells were selected by sorting for GFP, and cell lysates were immunoprecipitated with C/EBPP specific antibodies. C/EBPβ-PhosphoT217 and caspase 8 irnmunoblots were performed in C/EBPβ immunoprecipitates. Dominant negative RSK or C/EPBβ-A217 prevented C/EPBβ phosphorylation and stimulated the association of unphosphorylated C/EBPβ with active caspase 8. β-Actin was used as an internal control for the immunoprecipitations. Results from triplicate samples of three independent experiments are shown.

[0018] Figure 5 illustrates that a C/EBPβ-A217 peptide blocks activation of RSK. RSK activity was determined in a cell-free system as described in Methods. Recombinant RSK was activated with ATP (125 μM) in the presence or absence of KTVD (200 μM), KAVD (200 μM), or C/EBPβ2 iό-253-A217 (0.25 nM) peptides. Staurosporine was used as a control inhibitor (0.01 nM). All C/EBPβ peptides inhibited RSK activity to a similar extent as staurosporine (P < 0.01). Results from triplicate samples of two independent experiments are shown,

[0019] Figure 6 illustrates that C/EBPβ-A217 associates with active caspase 8 in hepatic stellate cells. Fig, 6a. Reciprocal caspase 8 ϊmmunoprecipitation of experiment described in Fig. 4a and 4b, confirmed the association of C/EBPβ-A217 with active caspase 8. β-Actin was used as an internal control for the immunoprecipitations. Fig. 6b. Reciprocal caspase 8 immunoprecipitation of experiment described in Fig. 4c, confirmed the association of C/EBPβ-A217 with active caspase 8. β-Actin was used as an internal control for the immunoprecipitations.

|0020] Figure 7 illustrates that active caspase 8 associates with TRADD and RIP. Fig. 7a. TRADD, C/EBPβ, RIP and caspase 8 immunoblots were performed on C/EBPβ immunoprecipitates from primary activated HSC treated with an ERK1/2 inhibitor (10 μM) or the cell permeable KA217VD peptide (200μM). Blocking the phosphorylation of C/EBPβ by RSK with the ERK1/2 inhibitor or the cell permeable KA217VD peptide, increased the association between C/EBPβ , active caspase 8, TRADD and RIP. P-Actin was used as an internal control for the immunoprecipitations. Fig. 7b. Reciprocal TRADD immunoprecipitations of experiment described in (a) confirmed the association of C/EBPβ with caspase 8, TRADD and RIP.

[0021J Figure 8 illustrates that the RS K- inhibitory peptide blocks hepatic stellate cell activation and liver fibrosis induced by CCU. Fig. 8a. Caspase 8 activity was measured in lysates from HSC isolated from C/EBPβ and C/EBPβ-A217 mice untreated or treated with CCl 4 for 24 hr, Caspase activity was increased in C/EBPβ-A217 mice treated with CCI 4 . Results from triplicate samples of two independent experiments are shown. Fig. 8b. Caspase activation in a cell-free system was determined. The Ac- KA217VD-CHO peptide enhanced the activation of caspase 8 at picomolar concentrations. Baseline caspase 8 activity was 3.8 U (100%). Results from triplicate

samples of three independent experiments are shown, P<0.01 for A217 peptide. Fig. 8c. Animate received a single injection of CCU or mineral oil. α-SMA (red) and C/EBPβ- PhosphoThr217 (green) were identified as in Fig. 3. Treatment with the cell permeable Ac-KA217 VD-CHO peptide blocked the expression of α-SMA and C/EBPβ- PhosphoThr217. Fig, 8d. PCNA (red) and active caspase 3 (green) were identified as in Fig. 3. Treatment with the Ac-KA217VD -CHO peptide blocked the expression of PCNA and induced active caspase 3. Fig. 8e. C/EBPβ +/í mice with severe liver fibrosis after treatment with CCU for 8 weeks or 12 weeks, while continuing on CC14, received the RSK inhibitory peptide (5 μg Lp., three times / week, for week 9 or 13, respectively, followed by 1 μg Lp., three times / week for weeks 10 -12 or 14-16, respectively), while continuing to induce iiver injury and Fibrosis with CCl 4 . These are representative Mallory's trichrome stain for liver fibrosis (in blue; arrowheads). Ail control mice n= 8 at 16-weeks) developed severe liver fibrosis, while mice receiving the RSK-inhibitory peptide (n=% at 12- weeks; and π=8 at 16-weeks) had no fibrosis or only minimal liver fibrosis (PO.01). f. In the experiment described in (Fig. Sd). hepatic collagen content (determined by extraction and purification as described in Methods) was decreased in mice treated with the RSK-inhibitory peptide (PO.01).

DETAILED DESCRIPTION OF THE INVENTION

|θO221 The present invention provides ribosomal S-6 kinase (RSK) inhibitory compounds, preferably peptides, or analogs thereof, for preventing or treating liver cirrhosis. In preferred embodiments, the RSK inhibitory peptide is a CCAAT/Enhancer Binding Protein-β subunit (C/EBPβ) mutant comprising an Alanine substitution at position 217 of the native C/EBPβ. In another preferred embodiment, the RSK inhibitory peptide is a C/EBPβ mutant comprising an amino acid sequence of KAVD (SEQ ID NO: 1) (C/EBPβ-A217). In yet another preferred embodiment, the RSK inhibitory peptide comprising an amino acid sequence of KAVDKLSDEYKMRRERNNIAVRKSRDKAKMRNLETQHK (SEQ ID NO:2) (C/EBPβ216-253-A217). The RSK inhibitory peptides of the present invention are believed to prevent and/or induce regression of liver fibrosis or cirrhosis by inhibiting RSK-C/EBPβ phosphorylation pathway, resulting in activation of capase 8 activity, and inducing apoptosis of hepatocyte stellate cells (HSC).

[0023] As used herein, the term "compound" refers to any chemical substances consisting of two or more different chemically bonded chemical elements with a determining composition. The "compound" used herein can be either naturally occurred (endogenous compounds) or chemically synthesized, including but not limited to any peptides, proteins, polynucleotides, oligonucleotides (antisense oligonucleotide agents), ribozymes, dsRNAs, RNAi, siRNAs, gene therapy vectors, vaccines, antibodies. Any techniques known to those of skill in the art for producing such compounds, including but not limited to the expression of peptides or proteins through standard molecular biologica! techniques including recombinant techniques, the isolation of peptides or proteins from natural sources, or the chemical synthesis of compounds are within the scope of the present invention.

|0024] As used herein, the term "peptide" refers to a chain of at least three amino acids joined by peptide bonds. The terms "peptide" and "protein' " are used interchangeably herein. The chain may be linear, branched, circular, or combinations thereof. As used herein, the term "analogs" refers to two amino acids that have the same or similar function, but that have evolved separately in unrelated organisms. As used herein, the term "analog" further refers to a structural derivative of a parent compound that often differs from it by a single element. As used herein, the term "analog" also refers to any peptide modifications known to the art, including but are not limited to changing the side chain of one or more amino acids or replacing one or more amino acid with any non-amino acids.

|0025] In certain embodiments the peptides and analogs of the present invention are isolated or purified. Protein purification techniques are well known in the art. These techniques involve, at one level, the homogenization and crude fractionation of the cells, tissue or organ to peptide and non-peptide fractions. The peptides of the present invention may be further purified using chromatographic and electrophoretic techniques to achieve partial or complete purification (or purification to homogeneity). Analytical methods particularly suited to the preparation of a pure peptide are ion- exchange chromatography, gel exclusion chromatography, polyacrylamide gel electrophoresis, affinity chromatography, immunoaffinity chromatography and isoelectric focusing. A particularly efficient method of purifying peptides is fast protein liquid chromatography (FPLC) or even HPLC.

[0026] An isolated peptide is intended to refer to a peptide/protein that is purified to any degree relative to its naturally-occurring state. Therefore, an isolated or purified peptide refers to a peptide free from at least some of the environment in which it may naturally occur. Generally, ''purified" will refer to a peptide composition that has been subjected to fractionation to remove various other components, and which composition substantially retains its expressed biological activity. Where the term "substantially purified" is used, this designation will refer to a composition in which the peptide forms the major component of the composition, such as constituting about 50%, about 60%, about 70%. about 80%. about 90%, about 95%, or more of the peptides in the composition.

(0027] Various methods for quantifying the degree of purification of the peptide are known in the art. These include, for example, determining the specific activity of an active fraction, or assessing the amount of peptides within a fraction by SDS/PAGE analysis. Various techniques suitable for use in peptide/protein purification are well known to those of skill in the art. These include, for example, precipitation with ammonium sulphate, PEG, antibodies and the like, or by heat denaturation, followed by: centrifugation; chromatography steps such as ion exchange, gel filtration, reverse phase, hydroxy lapatite and affinity chromatography; isoelectric focusing; gel electrophoresis; and combinations of these and other techniques. As is generally known in the art, it is believed that the order of conducting the various purification steps may be changed, or that certain steps may be omitted, and still result in a suitable method for the preparation of a substantially purified protein or peptide.

10028) There is no general requirement that the peptides and their analogs always be provided in their most purified state, indeed, it is contemplated that less substantially purified products will have utility in certain embodiments. Partial purification may be accomplished by using fewer purification steps in combination, or by utilizing different forms of the same general purification scheme. Methods exhibiting a lower degree of relative purification may have advantages in total recovery of protein product, or in maintaining the activity of an expressed protein. The invention contemplates compositions comprising the peptides and a pharmaceutically acceptable carrier.

[0029) In certain embodiments, the peptides and their analogs of the present invention may be attached to imaging agents including but are not limited to fluorescent, and/or

radioisotopes including but are not limited to 125 I, for imaging, diagnosis and/or therapeutic purposes. Many appropriate imaging agents and radioisotopes are known in the art, as are methods for their attachment to the peptides.

[0030] The present invention also provides isolated nucleotides, homologs and analogs comprising the nucleotide sequences encoding the aformentioned RSK inhibitory compounds, preferably peptides. In one of the preferred embodiments, the present invention provides an isolated nucleotide encoding a RSK inhibitory peptide comprising a C/EBPβ mutant having an Alanine substitution at position 217 of the native C/EBPβ. In yet another preferred embodiment, the present invention provides an isolated nucleotide encoding a RSK inhibitory peptide comprising an amino acid sequence of KAVD (SEQ ID NO: I) (C/EBPβ-A217). In yet another preferred embodiment, the present invention provides an isolated nucleotide encoding a RSK inhibitory peptide comprising an amino acid sequence of KAVDKLSDEYKMRRERNNIAVRKSRDKAKMRNLETQHK (SEQ ID NO:2) (C/EBPβ216-253-A217),

[0031] As used herein, the "nucleic acids" or "'nucleotides" may be derived from genomic DNA, complementary DNA (cDNA) or synthetic DNA. The term "nucleic acid" or "nucleotide" also refer to RNA or DNA that is linear or branched, single or double stranded, chemically modified, or a RNA/DNA hybrid thereof. It is contemplated that a nucleic acid within the scope of the present invention may comprise 3-100 or more nucleotide residues in length, preferably, 9-45 nucleotide residues in length, most preferably, 15-24 nucleotide residues in length. Where incorporation into an expression vector is desired, the nucleic acid may also comprise a natural intron or an intron derived from another gene. Less common bases, such as inosine, 5-methylcytosine, 6-rnethyladenine, hypoxanthine, and others can also be used.

(0032] An "isolated" nucleic acid molecule is one that is substantially separated from other nucleic acid molecules which are present in the natural source of the nucleic acid (i.e., sequences encoding other polypeptides). Preferably, an "isolated" nucleic acid is free of some of the sequences which naturally flank the nucleic acid (i.e., sequences located at the 5' and 3' ends of the nucleic acid) in its naturally occurring replicon. For example, a cloned nucleic acid is considered isolated. A nucleic acid is also considered isolated if it has been altered by human intervention, or placed in a locus or location

that is not its natural site, or if it is introduced into a eel! by agro infection. Moreover, an 'isolated" nucleic acid molecule, such as a cDNA molecule, can be free from some of the other cellular material with which it is naturally associated, or culture medium when produced by recombinant techniques, or chemical precursors or other chemicals when chemically synthesized.

I0033J As used herein, ''homologs" are defined herein as two nucleic acids or peptides that have similar, or substantially identical, nucleic acids or amino acid sequences, respectively. The term "homolog" further encompasses nucleic acid molecules that differ from one of the nucleotide sequences due to degeneracy of the genetic code and thus encodes the same amino acid sequences. In one of the preferred embodiments, homologs include allelic variants, orthologs, paralogs, agonists, and antagonists of nucleic acids encoding the peptide, or analogs thereof, of the present invention,

[0034] As used herein, the term "orthologs" refers to two nucleic acids from different species, but that have evolved from a common ancestral gene by speciation. Normally, orthologs encode peptides having the same or similar functions. In particular, orthologs of the invention will generally exhibit at least 80-85%, more preferably 85-90% or 90- 95%, and most preferably 95%, 96%, 97%, 98%, or even 99% identity, or 100% sequence identity, with all or part of the amino acid sequence of the RSK inhibitory peptides, or analogs thereof, of the present invention, preferably, SEQ ID NO: 1, or mutants thereof, and will exhibit a function similar to these RSK inhibitory peptides. Preferably, the orthologs of the present invention are RSK inhibitors that are capable of interfering RSK-C/EBPβ phosphorylation pathway, resulting in activation of capase 8 activity, and inducing regression of liver fibrosis and/or cirrhosis. As also used herein, the term "paralogs" refers to two nucleic acids that are related by duplication within a genome, Paralogs usually have different functions, but these functions may be related (Tatusov et al., 1997, Science 278(5338):631-637).

(00351 To determine the percent sequence identity of two amino acid sequences (e.g., SEQ ID NO: 1, and a mutant form thereof), the sequences are aligned for optimal comparison purposes (e.g., gaps can be introduced in the sequence of one polypeptide for optimal alignment with the other polypeptide or nucleic acid). The amino acid residues at corresponding amino acid positions are then compared. When a position in one sequence (e.g., SEQ ID NO: 1) is occupied by the same amino acid residue as the

corresponding position in the other sequence (e.g., a mutant form of the sequence selected from the peptide sequences of SEQ ID NO: 1), then the molecules are identical at that position. The same type of comparison can be made between two nucleic acid sequences.

[0036] The percent sequence identity between the two sequences is a function of the number of identical positions shared by the sequences (i.e., percent sequence identity = numbers of identical positions/total numbers of positions x 100). Preferably, the isolated amino acid homologs included in the present invention are at least about 50- 60%, preferably at least about 60-70%, and more preferably at least about 70-75%, 75- 80%, 80-85%, 85-90%, or 90-95%, and most preferably at least about 96%, 97%, 98%, 99%, or more identical to an entire amino acid sequence of the aforementioned RSK inhibitory peptides, preferably, SEQ ID NO: 1. In one preferred embodiment, the isolated nucleic acid homologs of the present invention encode RSK inhibitory peptides, or portion thereof, that is at least 90%, more preferably at least 95% identical to an amino acid sequence of SEQ ID NO: 1, and inhibit RSK-C/EBPβ phosphorylation pathway, resulting in regression of liver fibrosis and/or cirrhosis. In yet another preferred embodiment, the isolated nucleic acid homologs of the present invention encode amino acid sequences, or portions thereof, that is at least 90%, more preferably at least 95% identical to an amino acid sequence of SEQ ID NO:2, and inhibit RSK- C/EBPβ phosphorylation pathway, resulting tn regression of liver Fibrosis and/or cirrhosis.

10037) The determination of the percent sequence identity between two nucleic acid or peptide sequences is well known in the art. For instance, the Vector NTI 6.0 (PC) software package (ϊnforMax, 7600 Wisconsin Ave., Bethesda, MD 20814) to determine the percent sequence identity between two nucleic acid or peptide sequences can be used. In this method, a gap opening penalty of 15 and a gap extension penalty of 6.66 are used for determining the percent identity of two nucleic acids. A gap opening penalty of 10 and a gap extension penalty of 0.1 are used for determining the percent identity of two polypeptides. All other parameters are set at the default settings. For purposes of a multiple alignment (Clustal W algorithm), the gap opening penalty is 10, and the gap extension penalty is 0.05 with blosum62 matrix. It is to be understood that for the purposes of determining sequence identity when comparing a

DNA sequence to an RNA sequence, a thymidine nucleotide is equivalent to a uracil nucleotide.

[0038] In another aspect, the present invention provides an isolated nucleic acid comprising a nucleotide sequence that hybridizes to the nucleotides encoding the amino acid sequence shown in SEQ ID NO: 1 under stringent conditions, and inhibit RSK-

C/EBPβ phosphorylation pathway, resulting in regression of liver fibrosis and/or cirrhosis. In yet another aspect, the present invention provides an isolated nucleic acid comprising a nucleotide sequence that hybridizes to the nucleotides encoding the amino acid sequences of SEQ ID NO:2, under stringent conditions, and inhibit RSK-C/EBPβ phosphorylation pathway, resulting in regression of liver fibrosis and/or cirrhosis.

[0039] As used herein with regard to hybridization for DNA to a DNA blot, the term "stringent conditions" refers to hybridization overnight at 60°C in 1OX Denhart's solution, 6X SSC, 0.5% SDS, and 100 μg/ml denatured salmon sperm DNA. Blots are washed sequentially at 62°C for 30 minutes each time in 3X SSC/0.1% SDS, followed by IX SSC/0.1% SDS, and finally 0.1X SSC/0.1 % SDS. As also used herein, in a preferred embodiment, the phrase "'stringent conditions" refers to hybridization in a 6X SSC solution at 65°C. In another embodiment "highly stringent conditions" refers to hybridization overnight at 65°C in 1OX Denhart's solution, 6X SSC, 0.5% SDS and 100 μg/ml denatured salmon sperm DNA. Blots are washed sequentially at 65°C for 30 minutes each time in 3X SSC/0.1% SDS 3 followed by IX SSC/0.1% SDS, and finally 0.1X SSC/0.1% SDS. Methods for nucleic acid hybridizations are described in Meinkoth and Wahl, 1984, Anal. Biochem. 138:267-284; Current Protocols in Molecular Biology, Chapter 2, Ausubel et al., eds., Greene Publishing and Wiley- Interscience, New York, 1995; and Tijssen, 1993, Laboratory Techniques in Biochemistry and Molecular Biology: Hybridization with Nucleic Acid Probes, Part I, Chapter 2, Elsevier, New York, 1993.

[0040J Using the above-described methods, and others known to those of skill in the art, one of ordinary skill in the art can isolate homologs of the aforementioned RSK inhibitory peptides comprising the amino acid sequence shown in SEQ ID NO: 1. In yet another preferred embodiment, one of ordinary skill in the art can also isolate homologs of the aforementioned RSK inhibitory peptides comprising a amino acid sequence of

SEQ ID NO:2, One subset of these homologs are allelic variants. As used herein, the term "allelic variant * ' refers to a nucleotide sequence containing polymorphisms that lead to changes in the amino acid sequences of the peptides of the present invention without altering the functional activities. Such allelic variations can typically result in 1-5% variance in nucleic acids encoding the RSK inhibitory peptides of the present invention (e.g., SEQ ID NO: I, or SEQ ID NO:2).

[00411 In addition, the skilled artisan wil! further appreciate that changes can be introduced by mutation into a nucleotide sequence that encodes the amino acid sequence of the RSK inhibitory peptide, or analog thereof (e.g., SEQ ID NO: I, or SEQ ID NO:2). For example, nucleotide substitutions leading to amino acid substitutions at "non-essential" amino acid residues can be made in a sequence encoding the amino acid sequence of the peptides, or analogs thereof, of the present invention. A "nonessential" amino acid residue is a residue that can be altered without altering the activity of said peptide, whereas an "essential" amino acid residue is required for desired activity of such peptide, such as enhance or facilitate transdermal delivery of any drugs.

10042] In one embodiment, the isolated nucleic acid molecule comprises a nucleotide sequence encoding the RSK inhibitory peptide, wherein the RSK inhibitory peptide comprises an amino acid sequence at least about 50% identical to an amino acid sequence of SEQ ID NO: 1. or SEQ ID NO:2. Preferably, the peptide encoded by the nucleic acid molecule is at least about 50-60% identical to an amino acid sequence of SEQ ID NO: I, or SEQ ID NO:2, more preferably at least about 60-70% identical, even more preferably at least about 70-75%, 75-80%, 80-85%, 85-90%, or 90-95% identical, and most preferably at least about 96%, 97%, 98%, or 99% identical to an amino acid sequence of SEQ ID NO: 1, or SEQ ID NO:2.

10043) An isolated nucleic acid molecule encoding the RSK inhibitory peptides of the present invention can be created by introducing one or more nucleotide substitutions, additions, or deletions into a nucleotide encoding the peptide sequence, such that one or more amino acid substitutions, additions, or deletions are introduced into the encoded peptide and/or the side chain of the amino acids constituting the encoded peptides. Mutations can be introduced into the nucleic acid sequence encoding the peptide sequence of the present invention by standard techniques, such as site-directed

mutagenesis and PCR-mediated mutagenesis. Preferably, conservative amino acid substitutions are made at one or more predicted non-essential amino acid residues. 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.

100441 Families of amino acid residues having similar side chains have been defined in the art. These families include amino acids with basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine), nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan), beta-branched side chains (e.g., threonine, valine, isoleucine), and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine). Following mutagenesis of the nucleic acid sequence encoding the RSK inhibitory peptides of the present invention, the encoded RSK inhibitory peptide can be expressed reconibinantly and the RSK activity can be determined.

[004Sj The nucleotides of the present invention may be produced by any means, including genomic preparations, cDNA preparations, in vitro synthesis, RT-PCR, and in vitro or in vivo transcription. It is contemplated that peptides of the present invention, their variations and mutations, or fusion peptides/proteins may be encoded by any nucleic acid sequence that encodes the appropriate amino acid sequence. The design and production of nucleic acids encoding a desired amino acid sequence is well known to those of skill in the art based on standardized codons. In preferred embodiments, the codons selected for encoding each amino acid may be modified to optimize expression of the nucleic acid in the host cell of interest. Codon preferences for various species of host cell are well known in the art.

j0046j Any peptides and their analogs comprising the isolated peptides of the present invention can be made by any techniques known to those of skill in the art, including but are not limited to the recombinant expression through standard molecular biological techniques, the conventional peptide/protein purification and isolation methods, and/or the synthetic chemical synthesis methods. The nucleotide and peptide sequences corresponding to various genes may be found at computerized databases known to those of ordinary skill in the art, for instance, the National Center for Biotechnology Information's Genbank and GenPept databases (National Center for Biotechnology

Information). Alternatively, various commercial preparations of proteins and peptides are known to those of skill in the art.

[00471 Because the length of the isolated peptides of the present invention is relatively short, peptides and analogs comprising the amino acid sequences of these isolated peptide inserts can be chemically synthesized in solution or on a solid support in accordance with conventiona! techniques. Various automatic synthesizers are commercially available and can be used in accordance with known protocols. Short peptide sequences, usually from about 6 up to about 35 to 50 amino acids, can be readily synthesized by such methods. Alternatively, recombinant DNA technology may be employed wherein a nucleotide sequence which encodes a peptide and its analog of the present invention is inserted into an expression vector, transformed or transfected into an appropriate host cell, and cultivated under conditions suitable for expression.

[0048] Peptide mimetics may also be used for preparation of the peptides and their analogs of the present invention, Mimetics are peptide-containing molecules that mimic elements of protein secondary structure. A peptide mimetic is expected to permit molecular interactions similar to the natural molecule, and may be used to engineer second generation molecules having many of the natural properties of the peptides, but with altered and even improved characteristics.

[00491 The present invention also provides chimeric or fusion peptides that comprise the aforementioned RSK compounds, peptides, and/or analogs thereof. As used herein, a "chimeric or fusion peptide" comprises the amino acid sequence corresponding to the amino acid sequence of the aformentioned RSK peptides, or analogs thereof, operatively linked, preferably at the N- or C-terminus, to all or a portion of a second peptide or protein. As used herein, "the second peptide or protein" refer to a peptide or protein having an amino acid sequence which is not substantially identical to the amino acid sequences of the aforementioned RSK peptides, analogs, or mutants thereof, e.g., a peptide or protein that is different from SEQ ID NO: 1 or SEQ ID NO:2, and is derived from the same or a different organism. With respect to the fusion peptide, the term "operatively linked'' is intended to indicate that the amino acid of the peptides, or analogs thereof, of the present invention, and the second peptide or protein are fused to

each other so that both sequences fulfill the proposed function attributed to the sequence used.

100501 For example, fusions may employ leader sequences from other species to permit the recombinant expression of a protein in a heterologous host. Another useful fusion includes the addition of an immunologically active domain, such as an antibody epitope, to facilitate purification of the fusion protein. Inclusion of a cleavage site at or near the fusion junction will facilitate removal of the extraneous polypeptide after purification. Other useful fusions include linking of functional domains, such as active sites from enzymes, glycosylation domains, cellular targeting signals or transmembrane regions. In preferred embodiments, the fusion proteins of the present invention comprise the peptide and/or analog comprising amino acid sequences of the displayed peptide identified from the in vivo phage display, that is linked to a therapeutic protein or peptide. Examples of proteins or peptides that may be incorporated into a fusion protein include cytostatic proteins, cytocidal proteins, pro-apoptosis agents, anti- angiogenic agents, hormones, cytokines, growth factors, peptide drugs, antibodies, Fab fragments antibodies, antigens, receptor proteins, enzymes, lectins, MHC proteins, cell adhesion proteins and binding proteins. These examples are not meant to be limiting and it is contemplated that within the scope of the present invention virtually any protein or peptide could be incorporated into a fusion protein comprising the peptides and analogs of the present invention. Furthermore, in certain preferred embodiments, the fusion proteins of the present invention exhibit enhanced transdermal penetration capability as compared to non-fusion proteins or peptides that have not fused with the peptides and analogs, as disclosed herein.

|005lj Methods of generating fusion peptides/proteins are well known to those of skill in the art. Such peptides/proteins can be produced, for example, by chemical attachment using bifunctional cross-linking reagents, by de novo synthesis of the complete fusion peptide/protein, or by standard recombinant DNA techniques that involve attachment of a DNA sequence encoding the peptides of present invention, as disclosed herein, to a DNA sequence encoding the second peptide or protein, followed by expression of the intact fusion peptide/protein using. For example, DNA fragments coding for the peptide sequences of the peptides, or analogs thereof, of the present invention, are ligated together in-frame in accordance with conventional techniques, for

example by employing blunt-ended or stagger-ended termini for ligation, restriction enzyme digestion to provide for appropriate termini, filling-in of cohesive ends as appropriate, alkaline phosphatase treatment to avoid undesirable joining and enzymatic ligation. In another embodiment, the fusion gene can be synthesized by conventional techniques including automated DNA synthesizers. Alternatively, PCR amplification of gene fragments can be carried out using anchor primers that give rise to complementary overhangs between two consecutive gene fragments that can subsequently be annealed and re-amplified to generate a chimeric gene sequence {See, for example, Current Protocols in Molecular Biology, Eds. Ausubel et ai. s 1992, John Wiley & Sons), Moreover, many expression vectors are commercially available that already encode a fusion moiety (e.g., a GST polypeptide). The nucleic acids encoding the aforementioned RSK compounds, peptides, analogs, or mutants thereof, can be cloned into such an expression vector such that the fusion moiety is linked in-frame to these nucleic acids encoding the RSK peptides, or analogs or mutants thereof.

[0052] The present invention further provides antibodies and/or vaccines generated from, and/or comprising the RSK inhibitory compounds, peptides, analogs thereof, for prevention and/or treatment of liver fibrosis and/or cirrhosis. The term "antibody" includes complete antibodies, as well as fragments thereof (e.g., F(ab')2, Fab. etc.) and modified antibodies produced therefrom (e.g., antibodies modified through chemical, biochemical, or recombinant DNA methodologies), with the proviso that the antibody fragments and modified antibodies retain antigen binding characteristics sufficiently similar to the starting antibody so as to provide for specific detection of antigen.

[0053] Antibodies may be prepared in accordance with conventional ways, where the expressed polypeptide or protein is used as an immunogen, by itself or conjugated to known immunogenic carriers, e.g. KLH 5 pre-S HBsAg, other viral or eukaryotic proteins, or the like. Various adjuvants may be employed, with a series of injections, as appropriate. For monoclonal antibodies, after one or more booster injections, the spleen is isolated, the lymphocytes immortalized by cell fusion, and then screened for high affinity antibody binding. The immortalized cells, i.e. hybridomas, producing the desired antibodies may then be expanded. For further description, see Monoclonal Antibodies: A Laboratory Manual, Harlow and Lane eds., Cold Spring Harbor Laboratories, Cold Spring Harbor, N. Y., 1988. If desired, the mRNA encoding the

heavy and light chains may be isolated and mutagenized by cloning in E. coli, and the heavy and light chains mixed to further enhance the affinity of the antibody. Alternatives to in vivo immunization as a method of raising antibodies include binding to phage display libraries, usually in conjunction with in vitro affinity maturation.

[0054] As used herein, the term "vaccine" refers to a product that produces immunity therefore protecting the body from the disease. Vaccines that comprise a suspension of attenuated or killed microorganism (e.g. bacterial, viruses, or) are administered for the prevention, amelioration or treatment of infectious diseases. In preferred embodiments, the present invention provides vaccines generated from, and/or comprising the RSK inhibitory compounds, peptides, mutants, or analogs thereof.

[0055] The present invention further provides a pharmaceutical composition for preventing and/or treating liver fibrosis and/or cirrhosis comprising the aformentioned RSK compounds, peptides, mutants, or analogs thereof, of the present invention, and a pharmaceutically acceptable carrier and/or excipient. Pharmaceutically acceptable carriers and/or excipients are well known in the art, and have been amply described in variety of publications, including, for example, "Remington: The Science and Practice of Pharmacy", 19 th Ed. (1995).

[0056] The present invention further comprises methods for preventing or treating liver fibrosis and/or cirrhosis comprising administering to a subject in need an effective amount of a pharmaceutical composition comprising the aforementioned RSK inhibitory compounds, peptides, mutants, analogs, antibodies, vaccine thereof. In preferred embodiments, the aforementioned RSKcompounds, peptides, mutants, analogs, antibodies, or vaccines thereof, can be used as a therapeutic agent for treating liver fibrosis and/or cirrhosis, As used herein, the term "therapeutic agent," "or "drug" is used interchangeably to refer to a chemical material or compound that treating liver fibrosis and/or cirrhosis.

[0057] In yet another preferred embodiment, the aforementioned RSK inhibitory compounds, peptides, mutants, analogs, antibodies, vaccines thereof, can also be incorporated into vectors/virus and used for gene therapy. The term "gene therapy" refers to a technique for correcting defective genes responsible for disease development. Such techniques may include inserting a normal gene into a nonspecific

location within the genome to replace a nonfunctional gene; swapping an abnormal gene for a normal gene through homologous recombinations, reparing an abnormal gene to resume its normal function through selective reverse mutation; and altering or regulating gene expression and/or functions of a particular gene. In most gene therapy, a normal gene is inserted into the genome to replace an abnormal or disease-causing gene.

[0058] As used herein, a term "vector/virus" refers to a carrier molecule that carries and delivers the ''normal" therapeutic gene to the patient's target cells. Because viruses have evolved a way of encapsulating and delivering their genes to human cells in a pathogenic manner, most common vectors for gene therapy are viruses that have been genetically altered to carry the normal human DNA. As used herein, the viruses/vectors for gene therapy include retroviruses, adenoviruses, adeno-associated viruses, and herpes simplex viruses. The term "retrovirus" refers to a class of viruses that can create double-stranded DNA copies of their RNA genomes, which can be further integrated into the chromosomes of host cells, for example, Human immunodeficiency virus (HlV) is a retrovirus. The term "adenovirus" refers to a class of viruses with doubie-stranded DNA genomes that cause respiratory, intestinal, and eye infections in human, for instance, the virus that cause the common cold is an adenovirus. The term "adeno-associated virus" refers to a class of small, single- stranded DNA viruses that can insert their genetic material at a specific site on chromosome 19. The term "herpes simplex viruses" refers to a class of double- stranded DNA viruses that infect a particular cell type, neurons. Herpes simplex virus type 1 is a common human pathogen that causes cold sores,

(0059] As used herein, the terms "treatment," "'treating," and the like, refer to obtaining a desired pharmacologic and/or physiologic effect. The effect may be prophylactic in terms of completely or partially preventing a symptom thereof and/or may be therapeutic in terms of a partial or complete cure for an adverse affect attributable to the condition. 'Treatment," as used herein, covers any treatment of an injury in a mammal, particularly in a human, and includes: (a) preventing formation of liver fibrosis and/or cirrhosis, arresting any complications, and minimizing its effects; (b) relieving the symptoms; (c) preventing the disease from occurring in a subject which may be predisposed to the disease but has not yet been diagnosed as having it; (d)

inhibiting the disease, i.e., arresting its development; and (e) relieving the disease, i.e., causing regression of the disease.

|0060] As used herein, the term "individual," "'host," "subject," and "patient" are used interchangeably herein, and refer to a mammal, including, but not limited to, murines, simians, humans, mammalian farm animals, mammalian sport animals, and mammalian pets, preferably, humans.

[0061] As used herein, the term "effective amount" or "therapeutically effective amount" means a dosage sufficient to provide treatment of the disease state being treated or to otherwise provide a desired pharmacologic and/or physiologic effect.

[0062] These and many other variations and embodiments of the invention will be apparent to one of skill in the art upon a review of the appended description and examples.

EXAMPLES

Example 1 : Induction of Liver Fibrosis in C/EBPβ-A217 Mice

[0063] Animal Procedures: C/EBPβ *7 ", C/EBPβ-A217 and C/EBPβ " ' " mice (23-27 g) each received intraperitoneal injections of CCU or mineral oil (50 μl) only once or weekly (for up to 16 weeks). In other chronic experiments, C/EBPβ +/+ mice (25 g) each received intraperitoneal injections of CCI 4 or mineral oil (50 μl) weekly (for up to 16 weeks), but after 8 weeks, animals received either saline (control) or the cell permeable KAVD (SEQ ID NO: 1) (Buck, M. et al., MoL Cell 8, 807-816 (2001)) (5 μg Lp., three times / week, for week 9, followed by 1 μg Lp., three times / week for weeks 10-12 or 10-16, respectively), while continuing to induce liver injury and fibrosis with CCl 4 . In the acute experiments, animals received the cell permeable KAVD (SEQ ID NO:1) (100 pg intraperitonealiy) at 18 hr and animals were sacrificed at 24 hr (Buck, M. et al., EMBO J. 13, 851-860 (1994)). In the chronic experiments, animals were sacrificed 24 hr after the last CCU injection.

[0064] Microscopy: Fluorescent labels were observed using antibodies against C/EBPβ, α-SMA, PCNA (Santa Cruz Biotechnology, Santa Cruz, California), active caspase 3 (PharMingen, San Diego, California) or C/EBPβ-PhosphoT217 (Buck, M. et

al., MoI. Cell 8, 807-816 (2001)) in a laser confocal microscope (Buck, M. et al., Mυl. Cell 8, 807-816 (2001); Buck, M. et al., MoL Cell 4, 1087-1092 (1999); Buck, M. et al., EMBO J. 20, 6712-6723 (2001)). Fluorochromes utilized were Alexa 488 and Alexa 594. At least 100 cells were analyzed per experimental point (Muck et at, EMBO J, 13: 851-860 (1994)). TO-PRO-3 (Molecular Probes, Eugene, Oregon) was used to analyze nuclear morphology. The degree of liver fibrosis was determined by using the Mallory's trichrome and the Sirius red Immunohistochemistry (Jimenez, W. et al Hepatology 5, 815-818 (1985); Bedossa, P. et al., Hepatology 20, 15-20 (1994)). The interobserver agreement was > 90%.

Liver Inflammation Genes

[0065] The liver expression of 86 inflammation genes was determined by using the RT 2 Quantitative Real-Time PCR Array as described by the manufacturer (SuperArray, Frederick, MD). Control and experimental liver samples were analyzed together with internal control samples for the RNA purification and amplification steps, as well as for housekeping genes (β-glucuronidase, hypoxanthine guanine phosphoribosyl transferase 1, heat shock protein 1 β, g Iy ceraidehyde-3 -phosphate dehydrogenase, and β-actin ), using the BioRad iQ5 real-time PCR detection system (BioRad, Hercules, CA).

(0066] RSK-inhibitory compound, preferably a peptide or peptide analog, blocks the phosphorylation of mouse induce ϋver cirrhosis in mice C/EBPβ on T217 and induce HSC apoptosis and decrease liver fibrosis. Upon the chronic exposure to the hepatotoxin CCU produces liver cirrhosis in mice expressing the RSK-inhibitory C/EBPβ-A217 transgene, These animals are developmental Iy normal, fertile and have a normal life span (Buck, M. et al., MoI. Cell 8, 807-816 (2001)).

[0067] The data indicated that that after the administration of CCU for 12 weeks, all C/EBPβ +/r mice had severe liver fibrosis (cirrhosis) (grade 4; «=12), while all C/EBPβ- A217 mice had minimal or no liver fibrosis (Fig. Ia). These findings were confirmed by analysis of liver collagen with the Sirius red binding assay (Fig. Ib and Ic), and by confocal microscopy using specific antibodies against collagen type 1 (Fig. 2).

10068) Further, after the administration of CCl 4 , the hepatic collagen was markedly abnormal, adopting a cirrhotic pattern, by histochemical analysis (Fig. Ib), and its

content increased approximately 3 -fold from baseline in C/EBPβ í/+ (wt) mice (PO.001) while remaining unchanged in C/EBPβ-A217 mice (NS) (Fig. Ic). The hepatic collagen pattern and content of C/EBPβ τ/+ (wt) mice treated with CCl 4 for 12 weeks are similar to those of patients with liver cirrhosis (Gross, S. et ah, Science 286, 1365-1367 (1999). C/EBPβ "A (ko) mice were also refractory to the induction of liver fibrosis (P<0.01) (Fig. Ia, Ib and Ic).

[0069) In addition, Tables 1 and 2 indicated that C/EBPb-A217 mice had less liver injury (Table 1) and inflammation (Table 2) than C/EBPb +/V mice after CCl 4 treatment. Table 1 provided that thirty hours after a single intraperitoneal dose of CCU, C/EBPβ +/+ (n=9) and C/EBPβ 'A (n=9) mice had higher serum alanine aminotransferase (ALT) levels than C/EBPβ- A217 mice tø=9) (P < 0.005).

Table 1 , C/EBPβ- A217 mice have less liver damage after CCl 4 treatment.

(0070] A panel of 86 inflammatory genes were evaluated by RT-QPCR. The data provided that the expression of 21 inflammation genes was markedly decreased, while the expression of other 45 inflammation genes was unchanged in C/EBPβ-A217 mice after CCU-induced liver injury, when compared to control animals treated with CCl 4 .

Table 2. Decreased Inflammation in the Livers of C/EBPβ- A217 mice after CCl 4 treatment.

eneBank Symbol ,Description

[0071] Furthermore, Tables 1 and 2 showed that in addition to increased HSC apoptosis, partial resistance to ϋver necrosis and inflammation may contribute to the

prevention of liver cirrhosis in C/EBPβ-A217 mice, A decreased inflammatory response, mediated by hepatic macrophages, may be responsible for the decreased liver injury in C/EBPβ-A217 mice.

Example 2. Hepatic Stellate Ceil (HSC) Activation and Proliferation in C/EBPβ-A217 Mice

[0072] Cell Cultures: Adult C/EBPβ +/+ and C/EBPβ-A217 transgenic mice were used for the isolation of hepatic stellate cells as described (Buck. M. et al, MoI. Cell 8, 807- 816 (2001); Buck, M. et al., MoI, Cell 4, 1087-1092 (1999)). Stellate cells were prepared, by in situ perfusion and single-step density Nycodenz gradient (Accurate Chemical & Scientific Corp., Westbury, New York), as described previously (Lee, K. S. et al., J, Clin. Invest. 96, 2461-2468 (1995)). Stellate cells were identified by their typical autoffuorescence at 328nm excitation wavelength, staining of lipid droplets by oil red, and immunohistochemistry with a monoclonal antibody against desmin. Greater than 95% of the isolated cells were stellate cells. Primary mouse stellate cells freshly isolated from C/EBPβ +/+ mice and activated by collagen type 1 matrix, were transfected with vectors expressing RSK wild type, a catalytically inactive, dominant negative RSK mutant, or C/EBPβ-A2 ϊ7 together with GEP (Buck et al., MoI. Cell. 8: 807-816 (2001)). Transfected stellate cells were selected by sorting for GFP, and cell lysates were immunoprecipitated with C/EBPP specific antibodies. In other experiments, stellate cells were incubated for 24 hr with an ERK 1/2 inhibitor (Calbiochem 328006) (I0μM), or the KAVD peptide (200μM).

lmmunoprecipitation and Immunoblots

|0073] Pre-cleared stellate cell lysates were incubated for 2h with purified C/EBPβ, RSK, TRADD or caspase 8 antibodies followed by the addition of A/G+ agarose (Santa Cruz Biotechnology) for 12h. The immunoprecipitation reactions each contained 500 μg of total protein and 2 μg antibody (or purified IgG pre-immune serum as negative control). Immunoprecipϊtates were washed 3 times in 500 ml cell lysis buffer (Descombes, P. et al, Genes Dev. 4, 1541-1551 (1990)) and resolved by SDS-PAGE, and C/EBPβ, RSK, RSKp380, TRADD, RϊP, β-actin and caspase 8 detected by western blot (Buck et al., EMBO J. 15: 1753-65 (1996), Buck et al., EMBO J. 13: 851-860 (1994), and Trauwein et al.. Nature 364: 544-547 (1993)), following the

chemoluminescence protocol (Perkin-EImer, Shelton, Connecticut) using purified antibodies against C/EBPβ (C-19; aa 258-276), RSK, RSKp380, TRADD, RIP, β-actin (Santa Cruz Biotechnology), procaspase 8 (PharMingen) and C/EBPβ-PhosphoThr217 (Buck, M. et al., MoI. Cell 8, 807-816 (2001)). Negative samples were performed omitting the first antibody.

[0074) Chronic CCl 4 administration to C/EBPβ τ/+ (wt) mice, induced marked activation of stellate cells, as indicated by the positive immunofluorescence for α-smooth muscle actin (α-SMA) within the scars (Buck, M. et al., MoI. Cell 4, 1087-1092 (1999); Lee, K. S. et al, J. Clin, Invest. 96, 2461 -2468 (1995)) (Fig. 3a), and proliferation of HSC, as indicated by the presence of proliferating cell nuclear antigen (PCNA; DNA polymerase b auxiliary protein), an S-phase marker (Bravo, R. et al., Nature 326, 515- 517 (1987)) (Fig. 3b). By contrast, C/EBPβ-A217 mice were refractory to the induction of HSC activation and proliferation by CCU treatment (Fig. 3a and 3b). Moreover, chronic CCI 4 treatment induced the apoptotic cascade in HSC in the livers of C/EBPβ- A217 mice, but not C/EBPβ +/τ mice, as determined by the presence of active caspase 3 immunofluorescence (Fig. 3b). After chronic CCI 4 administration, C/EBPβ was phosphorylated on Thr217 in stellate cells of C/EBPβ +/~ mice, but not in C/EBPβ-A217 mice, as determined by confocal microscopy (Fig. 3a). using specific antibodies against this phosphorylated epitope (Buck, M. et al., MoI. Cell 8, 807-816 (2001)).

Example 3. C/EBPβ-A217 Inhibits RSK Activation in Hepatic Stellate Cells (HSC)

RSK Activity;

10075) RSK activity was measured by the QTL Lightspeed assay (QTL Biosystems; Santa Fe, New Mexico) using purified recombinant RSK-2 (4,333 U/mg) (Upstate, New York), and staurosporine (0.0 InM) as a control inhibitor. RSK activity was measured in the presence or absence of KTVD (200 μM), KAVD (200 μM), or C/EBP0216-253- A217 (0.25 nM) peptides.

Caspase Activity

[»0761 Purified synthetic N -acetyl, C-aldehyde KAVD tetrapeptide (American Peptide Company, Sunnyvale, California) were assayed for their ability to enhance the activity

of purified human recombinant caspase 8 (catalogue # 201-041-C005) (Alexis BiochemicaSs). The sequence of caspase 8 includes S217 through D479 cloned into an expression vector containing a 21 amino acid linker at the N-terminus. Thus, the prodomain (first 220 amino acids) is essentially missing. The fragment is cleaved at D385 and the active caspase 8 is essentially identical to that identified in apoptotic cells (Stennicke, H. R. et al,, J. Biol. Chem. 272, 25719-25723 (1997)). Caspase 8 activity was also measured in stellate cell iysates, using recombinant caspase 8 as a standard for activity. Caspase activity was determined by the release of the /?-nitroanaline coϊorimetric (Alexis Biochemicals, San Diego, California) substrate for caspase 8 (catalogue # 260-045) within the linear part of the kinetic assay 30 31. Active caspase 3 was determined with specific antibodies (PharMingen).

Statistical Analysis

|0077] Results are expressed as mean (± SD). Either the Student-? or the Wilcoxon Mann- Whitney tests were used to evaluate the differences of the means between groups for parametric and non-parametric populations, respectively, with a P value of <0.05 as significant.

(00781 A phosphor-RSK immunoblot was performed on RSK immunoprecipitates from protein lystates of purified HSC from C/EBPβ í/+ and C/EBPβ-A217 mice. C/EBPβ- A217 binding to, and blocking, RSK phosphorylation (Fig 4a) results in decreased phosphorylation of C/EBPβ on Thr217, and other target survival proteins by activated RSK (Buck et al., MoI. Cell 4: 1087-92 (1999), and Bonni et al., Science 286: 1358-62 (1999)). The C/EBPβ-A217 peptides, KAVD (SEQ ID NO:1) and C/EBPβ216-253- A217 (at nM concentrations), efficiently and directly blocked RSK's activation in a cell-free system (Fig. 5). The wild type (wt) peptide, KTVD (SEQ ID NO:3) also inhibited RSK by binding to the kinase but cannot be phosphorylated by RSK given its size (Fig. 5).

|0079] C/EBPβ-A217 was present with active caspase 8 in HSC from C/EBPβ-A217 mice after chronic CCU administration and, to a lesser extent, after mineral oil administration (Fig. 4b). In contrast, the association between inactive procaspase 8 and C/EBPβ-PhosphoT217 (Fig. 4b), as well as that between C/EBPβ and activated phospho-RSK (Fig. 4a), increased in HSC of C/EBPβ 4 /+ mice after chronic CCl 4

administration. Reciprocal immunoprecipitation with caspase 8 antibodies confirmed the presence of C/EBPβ-A217 with active caspase 8 (Fig. 5). RSK phosphorylation was inhibited in HSC from C/EBPβ-A217 mice, indicating that C/EBPβ-A217 not only associates with RSK but that also decreases its phosphorylation and activation (Fig. 4a). These data suggest that inhibition of RSK by nonphosphorylatable C/EBPβ-A217 is critical for caspase 8 activation, such findings were supported by the increased caspase 8 activation in HSC from C/EBPβ-A217 mice after chronic CCU administration (Fig. 4b).

iøOSO] Activation of caspase 8 was also studied. Activated primary mouse C/EBPβ + ' + HSC were transfected with vectors expressing green fluorescent protein with a control wild type (wt) RSK (GFP), with a dominant negative RSK mutant, or with the RSK- inhibitory dominant negative C/EBPβ-A217. C/EBPβ-PhosphoThr217 was markedly decreased in activated HSC expressing either the RSK. mutant or C/EBPβ-A217 (Fig. 4c). Moreover, unphosphorylated C/EBPβ was associated with the active caspase 8 in cells expressing the dominant negative RSK (Fig, 4c), which prevents C/EBPβ phosphorylation on T217 by RSK. In contrast, in the control cells expressing GFP and RSK wild type (wt) , C/EBPβ was phosphoryiated and associated with procaspase 8 (Fig. 4c), as reported previously (Buck, M. et al., MoI. Cell 8, 807-816 (2001)).

Example 4. RSK inhibitory peptide (C/EBPβ-A217) Activates Caspase 8 Activity in Hepatic Stellate Cells (HSC) and Induced Regression of Liver Fibrosis

10081) To activate HSC, a single dose of CCl 4 to C/EBPβ +/+ (wt) mice was administered, while control mice received the mineral oil vehicle (Rudolph, K. et al, Science 287, 1253-1258 (2000)). Six hours later, animals received an intraperitoneal injection of the cell permeable Ac-KA217 VD-CHO peptide (100 μg) or saline vehicle (100 μl). Animals were sacrificed at 24h.

[0082| Reciprocal immunoprecipitation with caspase 8 specific antibodies confirmed the presence of unphosphorylated C/EBPβ with active caspase 8 (Fig. 6b). After blocking the RSK-C/EBPβ phosphorylation cascade in activated HSC, with either an ERK 1/2 inhibitor or a cell permeable C/EBPβ-A217 peptide, Ac-KA217VD-CHO (SEQ ID NO: 1), unphosphorylated C/EBPβ became associated with other members of the

death receptor complex II, such as TRADD and RIP (Micheau, O. et al., Cell 1 14, 181- 190 (2003)) (Fig. 7). These associations were identified in C/EBPβ and TRADD immunoprecipitations (Fig. 7a and b). Caspase 8 activation was stimulated by C/EBPβ-A217 in HSC from C/EBPβ-A217 mice treated with CCl 4 (Fig. 8a). In addition, the peptide enhanced the activity of recombinant caspase 8 in a cell-free system at picomolar concentrations (Fig, 8b).

[0083] Acute CCl 4 administration induced both activation and proliferation of HSC (among other hepatic cells), judging by the expression of αSMA and PCNA 3 as determined by confocal microscopy (Fig. 8c and 8d). HSC activation and proliferation were blocked by treatment with the KAVD (SEQ ID NO:1) peptide, but not by treatment with saiine (Fig. 8c and 8d). Similarly to the findings of RSK inhibition in cell-free, cuitured primary stellate cells and in C/EBPβ-A217 transgenic mice, the KAVD (SEQ ID NO:1) peptide prevented the phosphorylation of C/EBPβ on Thr217 in HSC activated by the liver injury induced by the hepatotoxin CCl 4 (Fig. 8c). Further, in agreement to the findings of the increased caspase 8 activation in cell-free, cultured primary stellate cells and in C/EBPβ-A217 transgenic mice, the KAVD (SEQ ID NO:1) peptide stimulated the apoptotic pathway of HSC as indicated by the presence of active caspase 3 (Fig. 8d),

[0084] C/EBPβ "/+ mice was treated with severe liver fibrosis, after receiving CCU for either 8 weeks or 12 weeks, with the RSK inhibitory peptide (5 μg Lp., three times / week, for week 9 or 13, respectively, followed by 1 μg i.p., three times / week for weeks 10 -12 or 14-16, respectively), while continuing to induce liver injury and fibrosis with CCl 4 . Treatment of cirrhotic animals with the peptide, while continuing to receive CCU, prevented the progression and induced regression of liver fibrosis compared to control mice treated with CCl 4 . At week-12 or week-16, there was a marked regression of liver fibrosis judging by the trichrome stain (Fig. 8d) or by the hepatic collagen content (Fig. 8e). All control mice f«=24) had severe liver fibrosis, while all mice that received the RSK-inhibitory peptide (n ~ 16) had minimal or no liver fibrosis (P<0.0l) (Fig. 8d and 8e).

Appendix Sequence List

KAVD(SEQ1DNO:1)

KAVDKLSDEYKMRRERNNIAVRKSRDKAKMRNLETQHK (SEQ ID NO:2)

KTVD (SEQ ID NO:3)