Flt4 (vegfr-3) as a target for tumor imaging and anti-tumor therapy

Abstract

The present invention provide purified Flt4 receptor tyrosine kinase polypeptides and fragments thereof, polynucleotides encoding such polypeptides, antibodies that specifically bind such polypeptides, and uses therefor.

1 . A purified polypeptide comprising a portion of a mammalian Flt4 receptor tyrosine kinase (Flt4) extracellular domain (EC). 
     
     
         2 . A purified polypeptide according to  claim 1 , wherein the Flt4 is human. 
     
     
         3 . A purified polypeptide according to  claim 1 , wherein the Flt4 amino acid sequence is selected from the group consisting of SEQ ID NO: 2 and SEQ ID NO: 4. 
     
     
         4 . A purified polypeptide according to  claim 1 , wherein the fragment comprises Flt4 amino acid sequence capable of generating an immune response specific to Flt4. 
     
     
         5 . A purified polypeptide according to  claim 1 , wherein the fragment comprises Flt4 amino acid sequence capable of generating an immune response that produces antibodies which bind to Flt4 and fail to bind to Fin receptor tyrosine kinase. 
     
     
         6 . A purified polypeptide according to  claim 1 , comprising at least one immunoglobulin-like domain of the Flt4-EC. 
     
     
         7 . A purified polypeptide according to  claim 6 , comprising the first immunoglobulin-like domain of the Flt4-EC. 
     
     
         8 . A purified polypeptide according to  claim 6 , comprising the second immunoglobulin-like domain of the Flt4-EC. 
     
     
         9 . A purified polypeptide according to  claim 6 , comprising the third immunoglobulin-like domain of the Flt4-EC. 
     
     
         10 . A purified polypeptide according to  claim 6 , comprising the first, second, and third immunoglobulin domain of the Flt4-EC. 
     
     
         11 . A soluble polypeptide according to  claim 1 . 
     
     
         12 . A polynucleotide comprising a nucleotide sequence that encodes the polypeptide of  claim 1 . 
     
     
         13 . A polynucleotide according to  claim 12 , further comprising an expression control sequence operatively linked to the sequence the encodes the polypeptide. 
     
     
         14 . An expression vector comprising an expression control sequence operatively linked to a polynucleotide according to  claim 12 . 
     
     
         15 . An expression vector according to  claim 14 , wherein the expression control sequence comprises a promoter that promotes expression in a mammalian cell. 
     
     
         16 . An expression vector according to  claim 15  that is a viral vector selected from the group consisting of retrovirus, adenovirus, adeno-associated virus, vaccinia virus and herpesvirus. 
     
     
         17 . A host cell transformed or transfected with a vector according to  claim 15 . 
     
     
         18 . An isolated polypeptide comprising a Flt4 fragment that is encoded by a polynucleotide or oligonucleotide which hybridizes to a human gene encoding a FLT4 receptor tyrosine kinase, under hybridization conditions wherein said polynucleotide or oligonucleotide fails to hybridize to a human gene encoding FLT1, said hybridization conditions comprising:
 (a) a hybridization solution comprising 50% formamide, 5×Denhardt's solution, 5×SSPE, 0.1% SDS, and 0.1 mg/ml sonicated salmon sperm DNA;   (b) hybridization at a temperature of 42° C. for a duration of 18 to 24 hours; and   (c) washing following the hybridization at a wash temperature of 65° C., with a wash solution comprising 1×SSC and 0.1% SDS.   
     
     
         19 . An isolated polypeptide according to  claim 1 , wherein said Flt4 fragment is encoded by a polynucleotide or oligonucleotide that consists of a continuous nucleotide sequence of at least 200 nucleotides from a nucleotide sequence selected from the group consisting of: SEQ ID NO: 1, a nucleotide sequence complementary to SEQ ID NO: 1, SEQ ID NO: 3, and a nucleotide sequence complementary to SEQ ID NO: 3.