Recombinant bifunctional protein targeting cd47 and her2

Abstract

The present disclosure provides a recombinant fusion protein containing an extracellular Ig-like domain of a signal-regulator protein (SIRP), linked via a linker, to a paratope of an Ig-like anti-HER2 antibody at the N-terminus of a heavy chain or a light chain constituting the paratope. The present disclosure also provides a polynucleotide encoding the recombinant fusion protein, an expression vector containing the polynucleotide, a method for producing the recombinant protein and a method for treating a disease caused by over-expression of CD47 and/or HER2.

We claim: 
     
         1 . A recombinant fusion protein, comprising an extracellular Ig-like domain of a signal-regulatory protein (SIRP), linked via a linker, to a paratope of an Ig-like anti-HER2 antibody at the N-terminus of a heavy chain or a light chain constituting the paratope,
 wherein the signal-regulatory protein is SIRPα,   wherein the extracellular Ig-like domain of the signal-regulatory protein is first extracellular Ig-like domain of signal-regulatory protein (SIRPαD1),   wherein the amino acid sequence of SIRPαD1 has at least 90% sequence identity to SEQ ID NO: 2 and   wherein the recombinant fusion protein is capable of blocking binding of CD47s on cancer cells to SIRPs on surfaces of macrophages, binding to HER2s on cancer cells to inhibit uncontrolled cancer cell growth, and binding to FcRs on NK cells or macrophages.   
     
     
         2 . The recombinant fusion protein of  claim 1 , wherein each paratope of the Ig-like anti-HER2 antibody is linked to an extracellular Ig-like domain of signal-regulatory protein (SIRP) at the N-terminus of the heavy chain constituting that paratope. 
     
     
         3 . The recombinant fusion protein of  claim 1 , wherein each paratope of the Ig-like anti-HER2 antibody is linked to an extracellular Ig-like domain of signal-regulatory protein (SIRP) at the N-terminus of the light chain constituting that paratope. 
     
     
         4 . The recombinant fusion protein of  claim 1 , wherein one paratope of the Ig-like anti-HER2 antibody is linked to an extracellular Ig-like domain of signal-regulatory protein (SIRP) at the N-terminus of the heavy chain constituting that paratope, and the other paratope of the Ig-like anti-HER2 antibody is linked to an extracellular Ig-like domain of signal-regulatory protein (SIRP) at the N-terminus of the light chain constituting that paratope. 
     
     
         5 . The recombinant fusion protein of  claim 1 , wherein the linker is a peptide of 10 to 30 amino acid residues. 
     
     
         6 . The recombinant fusion protein of  claim 5 , wherein the linker is -(Gly-Gly-Gly-Gly-Ser) 3 - (SEQ ID NO: 22). 
     
     
         7 . The recombinant fusion protein of  claim 1 , wherein the Ig-like anti-HER2 antibody comprises two heavy chains each having an amino acid sequence with at least 80%, 85%, 90%, 95%, 98% or 99% identity to SEQ ID NO: 6, and two light chains each having an amino acid sequence with at least 80%, 85%, 90%, 95%, 98% or 99% identity to SEQ ID NO: 8. 
     
     
         8 . The recombinant fusion protein of  claim 7 , wherein each heavy chain has an amino acid sequence of SEQ ID NO: 6. 
     
     
         9 . The recombinant fusion protein of  claim 7 , wherein each light chain has an amino acid sequence of SEQ ID NO: 8. 
     
     
         10 . A polynucleotide encoding the recombinant fusion protein of  claim 1 . 
     
     
         11 . An expression vector comprising a polynucleotide of  claim 10 . 
     
     
         12 . A host cell comprising the expression vector of  claim 11 . 
     
     
         13 . A pharmaceutical composition, comprising the recombinant fusion protein of  claim 1 , and at least one pharmaceutical carrier. 
     
     
         14 . A method for treating a disease caused by over-expression of CD47 and/or HER2, comprising administering to a patient or a subject a therapeutically effective amount of the pharmaceutical composition of  claim 13 . 
     
     
         15 . The method of  claim 14 , wherein the disease is selected from the group consisting of acute myelocytic leukemia (AML), chronic myelocytic leukemia (CML), acute lymphoblastic leukemia (ALL), non-Hodgkin's lymphoma (NHL), multiple myeloma (MM), bladder cancer, ovarian cancer, prostate cancer, lung cancer, colon cancer, breast cancer, pancreatic cancer, and renal cell carcinoma. 
     
     
         16 . The method of  claim 14 , wherein the disease is selected from the group consisting of Crohn's disease, allergic asthma and rheumatoid arthritis. 
     
     
         17 . The recombinant fusion protein of  claim 1 , wherein the amino acid sequence of SIRPαD1 has at least 95% sequence identity to SEQ ID NO: 2. 
     
     
         18 . The recombinant fusion protein of  claim 1 , wherein the amino acid sequence of SIRPαD1 has at least 99% sequence identity to SEQ ID NO: 2. 
     
     
         19 . The recombinant fusion protein of  claim 1 , wherein the amino acid sequence of SIRPαD1 is SEQ ID NO: 2.