U.S. patent application number 11/375523 was filed with the patent office on 2007-01-11 for inhibitor of vascular endothelial cell growth factor.
Invention is credited to Richard L. Kendall, Kenneth A. JR. Thomas.
Application Number | 20070010442 11/375523 |
Document ID | / |
Family ID | 21901791 |
Filed Date | 2007-01-11 |
United States Patent
Application |
20070010442 |
Kind Code |
A1 |
Kendall; Richard L. ; et
al. |
January 11, 2007 |
Inhibitor of vascular endothelial cell growth factor
Abstract
The vascular endothelial cell growth factor (VEGF) inhibitors of
the present invention are naturally occurring or recombinantly
engineered soluble forms with or without a C-terminal transmembrane
region of the receptor for VEGF, a very selective growth factor for
endothelial cells. The soluble forms of the receptors will bind the
growth factor with high affinity but do not result in signal
transduction. These soluble forms of the receptor bind VEGF and
inhibit its function.
Inventors: |
Kendall; Richard L.;
(Edison, NJ) ; Thomas; Kenneth A. JR.; (Chatham
Borough, NJ) |
Correspondence
Address: |
MERCK AND CO., INC
P O BOX 2000
RAHWAY
NJ
07065-0907
US
|
Family ID: |
21901791 |
Appl. No.: |
11/375523 |
Filed: |
March 14, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10101018 |
Mar 19, 2002 |
7071159 |
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11375523 |
Mar 14, 2006 |
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09232773 |
Jan 15, 1999 |
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10101018 |
Mar 19, 2002 |
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08786164 |
Jan 21, 1997 |
5861484 |
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09232773 |
Jan 15, 1999 |
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08232538 |
Apr 21, 1994 |
5712380 |
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08786164 |
Jan 21, 1997 |
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08038769 |
Mar 25, 1993 |
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08232538 |
Apr 21, 1994 |
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Current U.S.
Class: |
514/8.1 ;
514/13.3; 530/350 |
Current CPC
Class: |
C07K 14/715 20130101;
A61K 38/00 20130101; C07K 14/71 20130101; A61P 43/00 20180101; A61P
9/00 20180101 |
Class at
Publication: |
514/012 ;
530/350 |
International
Class: |
A61K 38/18 20060101
A61K038/18; C07K 14/475 20060101 C07K014/475 |
Claims
1. A soluble VEGF inhibitor in substantially pure form which
specifically binds VEGF and inhibits cellular VEGF receptor
activity.
2. The soluble VEGF inhibitor according to claim 1 wherein the
soluble VEGF receptor is selected from the group consisting of
sVEGF-RI, sVEGF-RII, sVEGF-RTMI and sVEGF-RTMII.
3. The soluble VEGF inhibitor of claim 2 corresponding to sVEGF-RI
comprising the amino acid sequence: TABLE-US-00003 Met Val Ser Tyr
Trp Asp Thr Gly (SEQ. ID. NO.:6) Val Leu Leu Cys Ala Leu Leu Ser
Cys Leu Leu Leu Thr Gly Ser Ser Ser Gly Ser Lys Leu Lys Asp Pro Glu
Leu Ser Leu Lys Gly Thr Gln His Ile Met Gln Ala Gly Gln Thr Leu His
Leu Gln Cys Arg Gly Glu Ala Ala His Lys Trp Ser Leu Pro Glu Met Val
Ser Lys Glu Ser Glu Arg Leu Ser Ile Thr Lys Ser Ala Cys Gly Arg Asn
Gly Lys Gln Phe Cys Ser Thr Leu Thr Leu Asn Thr Ala Gln Ala Asn His
Thr Gly Phe Tyr Ser Cys Lys Tyr Leu Ala Val Pro Thr Ser Lys Lys Lys
Glu Thr Glu Ser Ala Ile Tyr Ile Phe Ile Ser Asp Thr Gly Arg Pro Phe
Val Glu Met Tyr Ser Glu Ile Pro Glu Ile Ile His Met Thr Glu Gly Arg
Glu Leu Val Ile Pro Cys Arg Val Thr Ser Pro Asn Ile Thr Val Thr Leu
Lys Lys Phe Pro Leu Asp Thr Leu Ile Pro Asp Gly Lys Arg Ile Ile Trp
Asp Ser Arg Lys Gly Phe Ile Ile Ser Asn Ala Thr Tyr Lys Glu Ile Gly
Leu Leu Thr Cys Glu Ala Thr Val Asn Gly His Leu Tyr Lys Thr Asn Tyr
Leu Thr His Arg Gln Thr Asn Thr Ile Ile Asp Val Gln Ile Ser Thr Pro
Arg Pro Val Lys Leu Leu Arg Gly His Thr Leu Val Leu Asn Cys Thr Ala
Thr Thr Pro Leu Asn Thr Arg Val Gln Met Thr Trp Ser Tyr Pro Asp Glu
Lys Asn Lys Arg Ala Ser Val Arg Arg Arg Ile Asp Gln Ser Asn Ser His
Ala Asn Ile Phe Tyr Ser Val Leu Thr Ile Asp Lys Met Gln Asn Lys Asp
Lys Gly Leu Tyr Thr Cys Arg Val Arg Ser Gly Pro Ser Phe Lys Ser Val
Asn Thr Ser Val His Ile Tyr Asp Lys Ala Phe Ile Thr Val Lys His Arg
Lys Gln Gln Val Leu Glu Thr Val Ala Gly Lys Arg Ser Tyr Arg Leu Ser
Met Lys Val Lys Ala Phe Pro Ser Pro Glu Val Val Trp Leu Lys Asp Gly
Leu Pro Ala Thr Glu Lys Ser Ala Arg Tyr Leu Thr Arg Gly Tyr Ser Leu
Ile Ile Lys Asp Val Thr Glu Glu Asp Ala Gly Asn Tyr Thr Ile Leu Leu
Ser Ile Lys Gln Ser Asn Val Phe Lys Asn Leu Thr Ala Thr Leu Ile Val
Asn Val Lys Pro Gln Ile Tyr Glu Lys Ala Val Ser Ser Phe Pro Asp Pro
Ala Leu Tyr Pro Leu Gly Ser Arg Gln Ile Leu Thr Cys Thr Ala Tyr Gly
Ile Pro Gln Pro Thr Ile Lys Trp Phe Trp His Pro Cys Asn His Asn His
Ser Glu Ala Arg Cys Asp Phe Cys Ser Asn Asn Glu Glu Ser Phe Ile Leu
Asp Ala Asp Ser Asn Met Gly Asn Arg Ile Glu Ser Ile Thr Gln Arg Met
Ala Ile Ile Glu Gly Lys Asn Lys Met Ala Ser Thr Leu Val Val Ala Asp
Ser Arg Ile Ser Gly Ile Tyr Ile Cys Ile Ala Ser Asn Lys Val Gly Thr
Val Gly Arg Asn Ile Ser Phe Tyr Ile Thr Asp Val Pro Asn Gly Phe His
Val Asn Leu Glu Lys Met Pro Thr Glu Gly Glu Asp Leu Lys Leu Ser Cys
Thr Val Asn Lys Phe Leu Tyr Arg Asp Val Thr Trp Ile Leu Leu Arg Thr
Val Asn Asn Arg Thr Met His Tyr Ser Ile Ser Lys Gln Lys Met Ala Ile
Thr Lys Glu His Ser Ile Thr Leu Asn Leu Thr Ile Met Asn Val Ser Leu
Gln Asp Ser Gly Thr Tyr Ala Cys Arg Ala Arg Asn Val Tyr Thr Gly Glu
Glu Ile Leu Gln Lys Lys Glu Ile Thr Ile Arg Gly Glu His Cys Asn Lys
Lys Ala Val Phe Ser Arg Ile Ser Lys Phe Lys Ser Thr Arg Asn Asp Cys
Thr Thr Gln Ser Asn Val Lys His.
4. The soluble VEGF inhibitor of claim 2 corresponding to sVEGF-RI
comprising the amino acid sequence: TABLE-US-00004 Ser Lys Leu Lys
Asp Pro Glu Leu (SEQ. ID. NO.:12) Ser Leu Lys Gly Thr Gln His Ile
Met Gln Ala Gly Gln Thr Leu His Leu Gln Cys Arg Gly Glu Ala Ala His
Lys Trp Ser Leu Pro Glu Met Val Ser Lys Glu Ser Glu Arg Leu Ser Ile
Thr Lys Ser Ala Cys Gly Arg Asn Gly Lys Gln Phe Cys Ser Thr Leu Thr
Leu Asn Thr Ala Gln Ala Asn His Thr Gly Phe Tyr Ser Cys Lys Tyr Leu
Ala Val Pro Thr Ser Lys Lys Lys Glu Thr Glu Ser Ala Ile Tyr Ile Phe
Ile Ser Asp Thr Gly Arg Pro Phe Val Glu Met Tyr Ser Glu Ile Pro Glu
Ile Ile His Met Thr Glu Gly Arg Glu Leu Val Ile Pro Cys Arg Val Thr
Ser Pro Asn Ile Thr Val Thr Leu Lys Lys Phe Pro Leu Asp Thr Leu Ile
Pro Asp Gly Lys Arg Ile Ile Trp Asp Ser Arg Lys Gly Phe Ile Ile Ser
Asn Ala Thr Tyr Lys Glu Ile Gly Leu Leu Thr Cys Glu Ala Thr Val Asn
Gly His Leu Tyr Lys Thr Asn Tyr Leu Thr His Arg Gln Thr Asn Thr Ile
Ile Asp Val Gln Ile Ser Thr Pro Arg Pro Val Lys Leu Leu Arg Gly His
Thr Leu Val Leu Asn Cys Thr Ala Thr Thr Pro Leu Asn Thr Arg Val Gln
Met Thr Trp Ser Tyr Pro Asp Glu Lys Asn Lys Arg Ala Ser Val Arg Arg
Arg Ile Asp Gln Ser Asn Ser His Ala Asn Ile Phe Tyr Ser Val Leu Thr
Ile Asp Lys Met Gln Asn Lys Asp Lys Gly Leu Tyr Thr Cys Arg Val Arg
Set Gly Pro Ser Phe Lys Ser Val Asn Thr Set Val His Ile Tyr Asp Lys
Ala Phe Ile Thr Val Lys His Arg Lys Gln Gln Val Leu Glu Thr Val Ala
Gly Lys Arg Ser Tyr Arg Leu Ser Met Lys Val Lys Ala Phe Pro Ser Pro
Glu Val Val Trp Leu Lys Asp Gly Leu Pro Ala Thr Glu Lys Ser Ala Arg
Tyr Leu Thr Arg Gly Tyr Ser Leu Ile Ile Lys Asp Val Thr Glu Glu Asp
Ala Gly Asn Tyr Thr Ile Leu Leu Set Ile Lys Gln Ser Asn Val Phe Lys
Asn Leu Thr Ala Thr Leu Ile Val Asn Val Lys Pro Gln Ile Tyr Glu Lys
Ala Val Ser Ser Phe Pro Asp Pro Ala Leu Tyr Pro Leu Gly Ser Atg Gln
Ile Leu Thr Cys Thr Ala Tyr Gly Ile Pro Gln Pro Thr Ile Lys Trp Phe
Trp His Pro Cys Asn His Asn His Ser Glu Ala Arg Cys Asp Phe Cys Ser
Asn Asn Glu Glu Ser Phe Ile Leu Asp Ala Asp Ser Asn Met Gly Asn Arg
Ile Glu Ser Ile Thr Gln Atg Met Ala Ile Ile Glu Gly Lys Asn Lys Met
Ala Ser Thr Leu Val Val Ala Asp Ser Arg Ile Ser Gly Ile Tyr Ile Cys
Ile Ala Ser Asn Lys Val Gly Thr Val Gly Arg Asn Ile Ser Phe Tyr Ile
Thr Asp Val Pro Asn Gly Phe His Val Asn Leu Glu Lys Met Pro Thr Glu
Gly Glu Asp Leu Lys Leu Ser Cys Thr Val Asn Lys Phe Leu Tyr Arg Asp
Val Thr Trp Ile Leu Leu Arg Thr Val Asn Asn Arg Thr Met His Tyr Ser
Ile Ser Lys Gln Lys Met Ala Ile Thr Lys Glu His Set Ile Thr Leu Asn
Leu Thr Ile Met Asn Val Ser Leu Gln Asp Ser Gly Thr Tyr Ala Cys Arg
Ala Arg Asn Val Tyr Thr Gly Glu Glu Ile Leu Gln Lys Lys Glu Ile Thr
Ile Arg Gly Glu His Cys Asn Lys Lys Ala Val Phe Ser Arg Ile Set Lys
Phe Lys Set Thr Arg Asn Asp Cys Thr Thr Gln Set Asn Val Lys
His.
5. The soluble VEGF inhibitor of claim 2 corresponding to sVEGF-RII
comprising the amino acid sequence: TABLE-US-00005
MQSKVLLAVALWLCVETRAASVGLPSVSLDLP (SEQ. ID. NO.:13)
RLSIQKDILTIKANTTLQITCRGQRDLDWLWP NNQSGSEQRVEVTECSDGLFCKTLTIPKVIGN
DTGAYKCFYRETDLASVIYVYVQDYRSPFIAS VSDQHGVVYITENKNKTVVIPCLGSISNLNVS
LCARYPEKRFVPDGNRISWDSKKGFTIPSYMI SYAGMVFCEAKINDESYQSIMYIVVVVGYRIY
DVVLSPSHGIELSVGEKLVLNCTARTELNVGI DFNWEYPSSKHQHKKLVNRDLKTQSGSEMKKF
LSTLTIDGVTRSDQGLYTCAASSGLMTKKNST FVRVHEKPFVAFGSGMESLVEATVGERVRIPA
KYLGYPPPEIKWYKNGIPLESNHTIKAGHVLT IMEVSERDTGNYTVILTNPISKEKQSHVVSLV
VYVPPQIGEKSLISPVDSYQYGTTQTLTCTVY AIPPPHHIHWYWQLEEECANEPSQAVSVTNPY
PCEEWRSVEDFQGGNKIAVNKNQFALIEGKNK TVSTLVIQAANVSALYKCEAVNKVGRGERVIS
FHVTRGPEITLQPDMQPTEQESVSLWCTADRS TFENLTWYKLGPQPLPIHVGELPTPVCKNLDT
LWKLNATMFSNSTNDILIMELKNASLQDQGDY VCLAQDRKTKKRHCVVRQLTVLER.
6. The soluble VEGF inhibitor of claim 2 corresponding to
sVEGF-RTMI comprising the amino acid sequence: TABLE-US-00006
MVSYWDTGVLLCALLSCLLLTGSSSGSKLKDP (SEQ. ID. NO.:14)
ELSLKGTQHIMQAGQTLHLQCRGEAAHKWSLP EMVSKESERLSITKSACGRNGKQFCSTLTLNT
AQANHTGFYSCKYLAVPTSKKKETESAIYIFI SDTGRPFVEMYSEIPEIIHMTEGRELVIPCRV
TSPNITVTLKKFPLDTLIPDGKRIIWDSRKGF IISNATYKEIGLLTCEATVNGHLYKTNYLTHR
QTNTIIDVQISTPRPVKLLRGHTLVLNCTATT PLNTRVQMTWSYPDEKNKRASVRRRIDQSNSH
ANIFYSVLTIDKMQNKDKGLYTCRVRSGPSFK SVNTSVHIYDKAFITVKHRKQQVLETVAGKRS
YRLSMKVKAFPSPEVVWLKDGLPATEKSARYL TRGYSLIIKDVTEEDAGNYTILLSIKQSNVFK
NLTATLIVNVKPQIYEKAVSSFPDPALYPLGS RQILTCTAYGIPQPTIKWFWHPCNHNHSEARC
DFCSNNEESFILDADSNMGNRIESITQRMAII EGKNKMASTLVVADSRISGIYICIASNKVGTV
GRNISFYITDVPNGFHVNLEKMPTEGEDLKLS CTVNKFLYRDVTWILLRTVNNRTMHYSISKQK
MAITKEHSITLNLTIMNVSLQDSGTYACRARN VYTGEEILQKKEITIRDQEAPYLLRNLSDHTV
AISSSTTLDCHANGVPEPQITWFKNNHKIQQE PGIILGPGSSTLFIERVTEEDEGVYHCKATNQ
KGSVESSAYLTVQGTSDKSNLELITLTCTCVA ATLFWLLLTLLI.
7. The soluble VEGF inhibitor of claim 2 corresponding to
sVEGF-RTMII comprising the amino acid sequence: TABLE-US-00007
MQSKVLLAVALWLCVETRAASVGLPSVSLDLP (SEQ. ID. NO.:15)
RLSIQKDILTIKANTTLQITCRGQRDLDWLWP NNQSGSEQRVEVTECSDGLFCKTLTIPKVIGN
DTGAYKCFYRETDLASVIYVYVQDYRSPFIAS VSDQHGVVYITENKNKTVVIPCLGSISNLNVS
LCARYPEKRFVPDGNRISWDSKKGFTIPSYMI SYAGMVFCEAKINDESYQSIMYIVVVVGYRIY
DVVLSPSHGIELSVGEKLVLNCTARTELNVGI DFNWEYPSSKHQHKKLVNRDLKTQSGSEMKKF
LSTLTIDGVTRSDQGLYTCAASSGLMTKKNST FVRVHEKPFVAFGSGMESLVEATVGERVRIPA
KYLGYPPPEIKWYKNGIPLESNHTIKAGHVLT IMEVSERDTGNYTVILTNPISKEKQSHVVSLV
VYVPPQIGEKSLISPVDSYQYGTTQTLTCTVY AIPPPHHIHWYWQLEEECANEPSQAVSVTNPY
PCEEWRSVEDFQGGNKIAVNKNQFALIEGKNK TVSTLVIQAANVSALYKCEAVNKVGRGERVIS
FHVTRGPEITLQPDMQPTEQESVSLWCTADRS TFENLTWYKLGPQPLPIHVGELPTPVCKNLDT
LWKLNATMFSNSTNDILIMELKNASLQDQGDY VCLAQDRKTKKRHCVVRQLTVLERVAPTITGN
LENQTTSIGESIEVSCTASGNPPPQIMWFKDN ETLVEDSGIVLKDGNRNLTIRRVRKEDEGLYC
QACSVLGCAKVEAFFIIEGAQEKTNLEIIILV GTTVIAMFFWLLLVIILGTV.
8. An expression vector comprising a promoter, and a DNA sequence
encoding a soluble VEGF inhibitor for expression in recombinant
host cells wherein the soluble VEGF inhibitor is selected from the
group consisting of sVEGF-RI, sVEGF-RII, sVEGF-RTMI and
sVEGF-RTMII.
9. The expression vector of claim 8 wherein the DNA encoding the
sVEGF-RI comprises the nucleotide sequence: TABLE-US-00008
GCGGACACTCCTCTCGGCTCCTCCCCGGCAGCGG (SEQ. ID. NO.:5)
CGGCGGCTCGGAGCGGGCTCCGGGGCTCGGGTGC
AGCGGCCAGCGGGCCTGGCGGCGAGGATTACCCG
GGGAAGTGGTTGTCTCCTGGCTGGAGCCGCGAGA
CGGGCGCTCAGGGCGCGGGGCCGGCGGCGGCGAA
CGAGAGGACGGACTCTGGCGGCCGGGTCGTTGGC
CGGGGGAGCGCGGGCACCGGGCGAGCAGGCCGCG TCGCGCTCACC ATG GTC AGC TAC TGG
GAC ACC GGG GTC CTG CTG TGC GCG CTG CTC AGC TGT CTG CTT CTC ACA GGA
TCT AGT TCA GGT TCA AAA TTA AAA GAT CCT GAA CTG AGT TTA AAA GGC ACC
CAG CAC ATC ATG CAA GCA GGC CAG ACA CTG CAT CTC CAA TGC AGG GGG GAA
GCA GCC CAT AAA TGG TCT TTG CCT GAA ATG GTG AGT AAG GAA AGC GAA AGG
CTG AGC ATA ACT AAA TCT GCC TGT GGA AGA AAT GGC AAA CAA TTC TGC AGT
ACT TTA ACC TTG AAC ACA GCT CAA GCA AAC CAC ACT GGC TTC TAC AGC TGC
AAA TAT CTA GCT GTA CCT ACT TCA AAG AAG AAG GAA ACA GAA TCT GCA ATC
TAT ATA TTT ATT AGT GAT ACA GGT AGA CCT TTC GTA GAG ATG TAC AGT GAA
ATC CCC GAA ATT ATA CAC ATG ACT GAA GGA AGG GAG CTC GTC ATT CCC TGC
CGG GTT ACG TCA CCT AAC ATC ACT GTT ACT TTA AAA AAG TTT CCA CTT GAC
ACT TTG ATC CCT GAT GGA AAA CGC ATA ATC TGG GAC AGT AGA AAG GGC TTC
ATC ATA TCA AAT GCA ACG TAC AAA GAA ATA GGG CTT CTG ACC TGT GAA GCA
ACA GTC AAT GGG CAT TTG TAT AAG ACA AAC TAT CTC ACA CAT CGA CAA ACC
AAT ACA ATC ATA GAT GTC CAA ATA AGC ACA CCA CGC CCA GTC AAA TTA CTT
AGA GGC CAT ACT CTT GTC CTC AAT TGT ACT GCT ACC ACT CCC TTG AAC ACG
AGA GTT CAA ATG ACC TGG AGT TAC CCT GAT GAA AAA AAT AAG AGA GCT TCC
GTA AGG CGA CGA ATT GAC CAA AGC AAT TCC CAT GCC AAC ATA TTC TAC AGT
GTT CTT ACT ATT GAC AAA ATG CAG AAC AAA GAC AAA GGA CTT TAT ACT TGT
CGT GTA AGG AGT GGA CCA TCA TTC AAA TCT GTT AAC ACC TCA GTG CAT ATA
TAT GAT AAA GCA TTC ATC ACT GTG AAA CAT CGA AAA CAG CAG GTG CTT GAA
ACC GTA GCT GGC AAG CGG TCT TAC CGG CTC TCT ATG AAA GTG AAG GCA TTT
CCC TCG CCG GAA GTT GTA TGG TTA AAA GAT GGG TTA CCT GCG ACT GAG AAA
TCT GCT CGC TAT TTG ACT CGT GGC TAC TCG TTA ATT ATC AAG GAC GTA ACT
GAA GAG GAT GCA GGG AAT TAT ACA ATC TTG CTG AGC ATA AAA CAG TCA AAT
GTG TTT AAA AAC CTC ACT GCC ACT CTA ATT GTC AAT GTG AAA CCC CAG ATT
TAC GAA AAG GCC GTG TCA TCG TTT CCA GAC CCG GCT CTC TAC CCA CTG GGC
AGC AGA CAA ATC CTG ACT TGT ACC GCA TAT GGT ATC CCT CAA CCT ACA ATC
AAG TGG TTC TGG CAC CCC TGT AAC CAT AAT CAT TCC GAA GCA AGG TGT GAC
TTT TGT TCC AAT AAT GAA GAG TCC TTT ATC CTG GAT GCT GAC AGC AAC ATG
GGA AAC AGA ATT GAG AGC ATC ACT CAG CGC ATG GCA ATA ATA GAA GGA AAG
AAT AAG ATG GCT AGC ACC TTG GTT GTG GCT GAC TCT AGA ATT TCT GGA ATC
TAC ATT TGC ATA GCT TCC AAT AAA GTT GGG ACT GTG GGA AGA AAC ATA AGC
TTT TAT ATC ACA GAT GTG CCA AAT GGG TTT CAT GTT AAC TTG GAA AAA ATG
CCG ACG GAA GGA GAG GAC CTG AAA CTG TCT TGC ACA GTT AAC AAG TTC TTA
TAC AGA GAC GTT ACT TGG ATT TTA CTG CGG ACA GTT AAT AAC AGA ACA ATG
CAC TAC AGT ATT AGC AAG CAA AAA ATG GCC ATC ACT AAG GAG CAC TCC ATC
ACT CTT AAT CTT ACC ATC ATG AAT GTT TCC CTG CAA GAT TCA GGC ACC TAT
GCC TGC AGA GCC AGG AAT GTA TAC ACA GGG GAA GAA ATC CTC CAG AAG AAA
GAA ATT ACA ATC AGA GGT GAG CAC TGC AAC AAA AAG GCT GTT TTC TCT CGG
ATC TCC AAA TTT AAA AGC ACA AGG AAT GAT TGT ACC ACA CAA AGT AAT GTA
AAA CAT TAA AGGACTCATTAAAAAGTAACAG
TTGTCTCATATCATCTTGATTTATTGTCACTGTT
GCTAACTTTCAGGCTCGGAGGAGATGCTCCTCCC
AAAATGAGTTCGGAGATGATAGCAGTAATAATGA
GACCCCCGGGCTCCAGCTCTGGGCCCCCCATTCA
GGCCGAGGGGGCTGCTCCGGGGGGCCGACTTGGT
GCACGTTTGGATTTGGAGGATCCCTGCACTGCCT
TCTCTGTGTTTGTTGCTCTTGCTGTTTTCTCCTG
CCTGATAAACAACAACTTGGGATGATCCTTTCCA
TTTTGATGCCAACCTCTTTTTATTTTTAAGCGGC GCCCTATAGT.
10. The expression vector of claim 8 wherein the DNA encoding the
sVEGF-RII comprises the nucleotide sequence: TABLE-US-00009
GGTGTGGTCGCTGCGTTTCCTCTGCCTGCGCC (SEQ. ID. NO.:16)
GGGCATCACTTGCGCGCCGCAGAAAGTCCGTC TGGCAGCCTGGATATCCTCTCCTACCGGCACC
CGCAGACGCCCCTGCAGCCGCGGTCGGCGCCC GGGCTCCCTAGCCCTGTGCGCTCAACTGTCCT
GCGCTGCGGGGTGCCGCGAGTTCCACCTCCGC GCCTCCTTCTCTAGACAGGCGCTGGGAGAAAG
AACCGGCTCCCGAGTTCCGGCATTTCGCCCGG CTCGAGGTGCAGGATGCAGAGCAAGGTGCTGC
TGGCCGTCGCCCTGTGGCTCTGCGTGGAGACC CGGGCCGCCTCTGTGGGTTTGCCTAGTGTTTC
TCTTGATCTGCCCAGGCTCAGCATACAAAAAG ACATACTTACAATTAAGGCTAATACAACTCTT
CAAATTACTTGCAGGGGACAGAGGGACTTGGA CTGGCTTTGGCCCAATAATCAGAGTGGCAGTG
AGCAAAGGGTGGAGGTGACTGAGTGCAGCGAT GGCCTCTTCTGTAAGACACTCACAATTCCAAA
AGTGATCGGAAATGACACTGGAGCCTACAAGT GCTTCTACCGGGAAACTGACTTGGCCTCGGTC
ATTTATGTCTATGTTCAAGATTACAGATCTCC ATTTATTGCTTCTGTTAGTGACCAACATGGAG
TCGTGTACATTACTGAGAACAAAAACAAAACT GTGGTGATTCCATGTCTCGGGTCCATTTCAAA
TCTCAACGTGTCACTTTGTGCAAGATACCCAG AAAAGAGATTTGTTCCTGATGGTAACAGAATT
TCCTGGGACAGCAAGAAGGGCTTTACTATTCC CAGCTACATGATCAGCTATGCTGGCATGGTCT
TCTGTGAAGCAAAAATTAATGATGAAAGTTAC CAGTCTATTATGTACATAGTTGTCGTTGTAGG
GTATAGGATTTATGATGTGGTTCTGAGTCCGT CTCATGGAATTGAACTATCTGTTGGAGAAAAG
CTTGTCTTAAATTGTACAGCAAGAACTGAACT AAATGTGGGGATTGACTTCAACTGGGAATACC
CTTCTTCGAAGCATCAGCATAAGAAACTTGTA AACCGAGACCTAAAAACCCAGTCTGGGAGTGA
GATGAAGAAATTTTTGAGCACCTTAACTATAG ATGGTGTAACCCGGAGTGACCAAGGATTGTAC
ACCTGTGCAGCATCCAGTGGGCTGATGACCAA GAAGAACAGCACATTTGTCAGGGTCCATGAAA
AACCTTTGTTGCTTTTGGAAGTGGCATGGAAT CTCTGGTGGAAGCCACGGTGGGGGAGCGTGTC
AGAATCCCTGCGAAGTACCTTGGTTACCCACC CCCAGAAATAAAATGGTATAAAAATGGAATAC
CCCTTGAGTCCAATCACACAATTAAAGCGGGG CATGTACTGACGATTATGGAAGTGAGTGAAAG
AGACACAGGAAATTACACTGTCATCCTTACCA ATCCCATTTCAAAGGAGAAGCAGAGCCATGTG
GTCTCTCTGGTTGTGTATGTCCCACCCCAGAT TGGTGAGAAATCTCTAATCTCTCCTGTGGATT
CCTACCAGTACGGCACCACTCAAACGCTGACA TGTACGGTCTATGCCATTCCTCCCCCGCATCA
CATCCACTGGTATTGGCAGTTGGAGGAAGAGT GCGCCAACGAGCCCAGCCAAGCTGTCTCAGTG
ACAAACCCATACCCTTGTGAAGAATGGAGAAG TGTGGAGGACTTCCAGGGAGGAAATAAAATTG
CCGTTAATAAAAATCAATTTGCTCTAATTGAA GGAAAAAACAAAACTGTAAGTACCCTTGTTAT
CCAAGCGGCAAATGTGTCAGCTTTGTACAAAT GTGAAGCGGTCAACAAAGTCGGGAGAGGAGAG
AGGGTGATCTCCTTCCACGTGACCAGGGGTCC TGAAATTACTTTGCAACCTGACATGCAGCCCA
CTGAGCAGGAGAGCGTGTCTTTGTGGTGCACT GCAGACAGATCTACGTTTGAGAACCTCACATG
GTACAAGCTTGGCCCACAGCCTCTGCCAATCC ATGTGGGAGAGTTGCCCACACCTGTTTGCAAG
AACTTGGATACTCTTTGGAAATTGAATGCCAC CATGTTCTCTAATAGCACAAATGACATTTTGA
TCATGGAGCTTAAGAATGCATCCTTGCAGGAC CAAGGAGACTATGTCTGCCTTGCTCAAGACAG
GAAGACCAAGAAAAGACATTGCGTGGTCAGGC AGCTCACAGTCCTAGAGCGTTAA.
11. The expression vector of claim 8 wherein the DNA encoding the
sVEGF-RTMI comprises the nucleotide sequence: TABLE-US-00010
GCGCTCACCATGGTCAGCTACTGGGACACCGG (SEQ. ID. NO.:17)
GGTCCTGCTGTGCGCGCTGCTCAGCTGTCTGC TTCTCACAGGATCTAGTTCAGGTTCAAAATTA
AAAGATCCTGAACTGAGTTTAAAAGGCACCCA GCACATCATGCAAGCAGGCCAGACACTGCATC
TCCAATGCAGGGGGGAAGCAGCCCATAAATGG TCTTTGCCTGAAATGGTGAGTAAGGAAAGCGA
AAGGCTGAGCATAACTAAATCTGCCTGTGGAA GAAATGGCAAACAATTCTGCAGTACTTTAACC
TTGAACACAGCTCAAGCAAACCACACTGGCTT CTACAGCTGCAAATATCTAGCTGTACCTACTT
CAAAGAAGAAGGAAACAGAATCTGCAATCTAT ATATTTATTAGTGATACAGGTAGACCTTTCGT
AGAGATGTACAGTGAAATCCCCGAAATTATAC ACATGACTGAAGGAAGGGAGCTCGTCATTCCC
TGCCGGGTTACGTCACCTAACATCACTGTTAC TTTAAAAAAGTTTCCACTTGACACTTTGATCC
CTGATGGAAAACGCATAATCTGGGACAGTAGA AAGGGCTTCATCATATCAAATGCAACGTACAA
AGAAATAGGGCTTCTGACCTGTGAAGCAACAG TCAATGGGCATTTGTATAAGACAAACTATCTC
ACACATCGACAAACCAATACAATCATAGATGT CCAAATAAGCACACCACGCCCAGTCAAATTAC
TTAGAGGCCATACTCTTGTCCTCAATTGTACT GCTACCACTCCCTTGAACACGAGAGTTCAAAT
GACCTGGAGTTACCCTGATGAAAAAAATAAGA GAGCTTCCGTAAGGCGACGAATTGACCAAAGC
AATTCCCATGCCAACATATTCTACAGTGTTCT TACTATTGACAAAATGCAGAACAAAGACAAAG
GACTTTATACTTGTCGTGTAAGGAGTGGACCA TCATTCAAATCTGTTAACACCTCAGTGCATAT
ATATGATAAAGCATTCATCACTGTGAAACATC GAAAACAGCAGGTGCTTGAAACCGTAGCTGGC
AAGCGGTCTTACCGGCTCTCTATGAAAGTGAA GGCATTTCCCTCGCCGGAAGTTGTATGGTTAA
AAGATGGGTTACCTGCGACTGAGAAATCTGCT CGCTATTTGACTCGTGGCTACTCGTTAATTAT
CAAGGACGTAACTGAAGAGGATGCAGGGAATT ATACAATCTTGCTGAGCATAAAACAGTCAAAT
GTGTTTAAAAACCTCACTGCCACTCTAATTGT CAATGTGAAACCCCAGATTTACGAAAAGGCCG
TGTCATCGTTTCCAGACCCGGCTCTCTACCCA CTGGGCAGCAGACAAATCCTGACTTGTACCGC
ATATGGTATCCCTCAACCTACAATCAAGTGGT TCTGGCACCCCTGTAACCATAATCATTCCGAA
GCAAGGTGTGACTTTTGTTCCAATAATGAAGA GTCCTTTATCCTGGATGCTGACAGCAACATGG
GAAACAGAATTGAGAGCATCACTCAGCGCATG GCAATAATAGAAGGAAAGAATAAGATGGCTAG
CACCTTGGTTGTGGCTGACTCTAGAATTTCTG GAATCTACATTTGCATAGCTTCCAATAAAGTT
GGGACTGTGGGAAGAAACATAAGCTTTTATAT CACAGATGTGCCAAATGGGTTTCATGTTAACT
TGGAAAAAATGCCGACGGAAGGAGAGGACCTG AAACTGTCTTGCACAGTTAACAAGTTCTTATA
CAGAGACGTTACTTGGATTTTACTGCGGACAG TTAATAACAGAACAATGCACTACAGTATTAGC
AAGCAAAAAATGGCCATCACTAAGGAGCACTC CATCACTCTTAATCTTACCATCATGAATGTTT
CCCTGCAAGATTCAGGCACCTATGCCTGCAGA GCCAGGAATGTATACACAGGGGAAGAAATCCT
CCAGAAGAAAGAAATTACAATCAGAGATCAGG AAGCACCATACCTCCTGCGAAACCTCAGTGAT
CACACAGTGGCCATCAGCAGTTCCACCACTTT AGACTGTCATGCTAATGGTGTCCCCGAGCCTC
AGATCACTTGGTTTAAAAACAACCACAAAATA CAACAAGAGCCTGGAATTATTTTAGGACCAGG
AAGCAGCACGCTGTTTATTGAAAGAGTCACAG AAGAGGATGAAGGTGTCTATCACTGCAAAGCC
ACCAACCAGAAGGGCTCTGTGGAAAGTTCAGC ATACCTCACTGTTCAAGGAACCTCGGACAAGT
CTAATCTGGAGCTGATCACTCTAACATGCACC TGTGTGGCTGCGACTCTCTTCTGGCTCCTATT
AACCCTCCTTATCTAA.
12. The expression vector of claim 8 wherein the DNA encoding the
sVEGF-RTMII comprises the nucleotide sequence: TABLE-US-00011 (SEQ.
ID. NO.: 18) CTCGAGGTGCAGGATGCAGAGCAAGGTGCTGCTGGCCGTCGCCCTGTGGC
TCTGCGTGGAGACCCGGGCCGCCTCTGTGGGTTTGCCTAGTGTTTCTCTT
GATCTGCCCAGGCTCAGCATACAAAAAGACATACTTACAATTAAGGCTAA
TACAACTCTTCAAATTACTTGCAGGGGACAGAGGGACTTGGACTGGCTTT
GGCCCAATAATCAGAGTGGCAGTGAGCAAAGGGTGGAGGTGACTGAGTGC
AGCGATGGCCTCTTCTGTAAGACACTCACAATTCCAAAAGTGATCGGAAA
TGACACTGGAGCCTACAAGTGCTTCTACCGGGAAACTGACTTGGCCTCGG
TCATTTATGTCTATGTTCAAGATTACAGATCTCCATTTATTGCTTCTGTT
AGTGACCAACATGGAGTCGTGTACATTACTGAGAACAAAAACAAAACTGT
GGTGATTCCATGTCTCGGGTCCATTTCAAATCTCAACGTGTCACTTTGTG
CAAGATACCCAGAAAAGAGATTTGTTCCTGATGGTAACAGAATTTCCTGG
GACAGCAAGAAGGGCTTTACTATTCCCAGCTACATGATCAGCTATGCTGG
CATGGTCTTCTGTGAAGCAAAAATTAATGATGAAAGTTACCAGTCTATTA
TGTACATAGTTGTCGTTGTAGGGTATAGGATTTATGATGTGGTTCTGAGT
CCGTCTCATGGAATTGAACTATCTGTTGGAGAAAAGCTTGTCTTAAATTG
TACAGCAAGAACTGAACTAAATGTGGGGATTGACTTCAACTGGGAATACC
CTTCTTCGAAGCATCAGCATAAGAAACTTGTAAACCGAGACCTAAAAACC
CAGTCTGGGAGTGAGATGAAGAAATTTTTGAGCACCTTAACTATAGATGG
TGTAACCCGGAGTGACCAAGGATTGTACACCTGTGCAGCATCCAGTGGGC
TGATGACCAAGAAGAACAGCACATTTGTCAGGGTCCCATGAAAAACCTTT
GTTGCTTTTGGAAGTGGCATGGAATCTCTGGTGGAAGCCACGGTGGGGGA
GCGTGTCAGAATCCCTGCGAAGTACCTTGGTTACCCACCCCCAGAAATAA
AATGGTATAAAAATGGAATACCCCTTGAGTCCAATCACACAATTAAAGCG
GGGCATGTACTGACGAATATGGAAGTGAGTGAAAGAGACACAGGAAATTA
CACTGTCATCCTTACCAATCCCATTTCAAAGGAGAAGCAGAGCCATGTGG
TCTCTCTGGTTGTGTATGTCCCACCCCAGATTGGTGAGAAATCTCTAATC
TCTCCTGTGGATTCCTACCAGTACGGCACCACTCAAACGCTGACATGTAC
GGTCTATGCCATTCCTCCCCCGCATCACATCCACTGGTATTGGCAGTTGG
AGGAAGAGTGCGCCAACGAGCCCAGCCAAGCTGTCTCAGTGACAAACCCA
TACCCTTGTGAAGAATGGAGAAGTGTGGAGGACTTCCAGGGAGGAAATAA
AATTGCCGTTAATAAAAATCAATTTGCTCTAATTGAAGGAAAAAACAAAA
CTGTAAGTACCCTTGTTATCCAAGCGGCAAATGTGTCAGCTTTGTACAAA
TGTGAAGCGGTCAACAAAGTCGGGAGAGGAGAGAGGGTCTGACATGCAGC
CCACTGAGCAGGAGAGCGTGTCTTTGTGGTGCACTGCAGACAGATCTACG
TTTGAGAACCTCACATGGTACAAGCTTGGCCCACAGCCTCTGCCAATCCA
TGTGGGAGAGTTGCCCACACCTGTTTGCAAGAACTTGGATACTCTTTGGA
AATTGAATGCCACCATGTTCTCTAATAGCACAAATGACATTTTGATCATG
GAGCTTAAGAATGCATCCTTGCAGGACCAAGGAGACTATGTCTGCCTTGC
TCAAGACAGGAAGACCAAGAAAAGACATTGCGTGGTCAGGCAGCTCACAG
TCCTAGAGCGTGTGGCACCCACGATCACAGGAAACCTGGAGAATCAGACG
ACAAGTATTGGGGAAAGCATCGAAGTCTCATGCACGGCATCTGGGAATCC
CCCTCCACAGATCATGTGGTTTAAAGATAATGAGACCCTTGTAGAAGACT
CAGGCATTGTATTGAAGGATGGGAACCGGAACCTCACTATCCGCAGAGTG
AGGAAGGAGGACGAAGGCCTCTACACCTGCCAGGCATGCAGTGTTCTTGG
CTGTGCAAAAGTGGAGGCATTTTTCATAATAGAAGGTGCCCAGGAAAAGA
CGAACTTGGAAATCATTATTCTAGTAGGCACGACGGTGATTGCCATGTTC
TTCTGGCTACTTCTTGTCATCATCCTAGGGACCGTTTAA.
13. A recombinant host cell containing the expression vector of
claim 8.
14. A method for inhibiting VEGF receptor function comprising the
administration of the VEGF inhibitor of claim 1 in an amount
sufficient to inhibit VEGF receptor function.
15. The method of claim 14 wherein the VEGF inhibitor is selected
from the group consisting of sVEGF-RI, sVEGF-RII, sVEGF-RTMI, and
sVEGF-RTMII.
16. A pharmaceutical composition comprising the inhibitor of claim
1 and a pharmaceutically acceptable carrier.
17. The pharmaceutical composition of claim 16 wherein the
inhibitor is selected from the group consisting of sVEGF-RI,
sVEGF-RII, sVEGF-RTMI, and sVEGF-RTMII.
18. A method for inhibiting angiogenesis comprising the
administration of the VEGF inhibitor of claim 1 in an amount
sufficient to inhibit angiogensis.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of application Ser. No.
10/101,018, filed Mar. 19, 2002, now U.S. Pat. No. 7,071,159; which
is a divisional of application Ser. No. 09/232,773 filed Jan. 15,
1999, now abandoned; which is a divisional of application Ser. No.
08/786,164 filed Jan. 21, 1997, now U.S. Pat. No. 5,861,484; which
is a divisional of application Ser. No. 08/232,538 filed Apr. 21,
1994, now U.S. Pat. No. 5,712,380 which is a continuation-in-part
application of application Ser. No. 08/038,769 filed Mar. 25, 1993,
now abandoned.
BACKGROUND OF THE DISCLOSURE
[0002] Recently a new class of cell-derived dimeric mitogens with
selectivity for vascular endothelial cells has been identified and
designated vascular endothelial cell growth factor (VEGF). VEGF has
been purified from conditioned growth media of rat glioma cells
[Conn et al., (1990), Proc. Natl. Acad. Sci. U.S.A., 87, pp
2628-2632]; and conditioned growth media of bovine pituitary
folliculo stellate cells [Ferrara and Henzel, (1989), Biochem.
Biophys. Res. Comm., 161, pp. 851-858; Gozpadorowicz et al.,
(1989), Proc. Natl. Acad. Sci. U.S.A., 86, pp. 7311-7315] and
conditioned growth medium from human U937 cells [Connolly, D. T. et
al. (1989), Science, 246, pp. 1309-1312]. VEGF is a dimer with an
apparent molecular mass of about 46 kDa with each subunit having an
apparent molecular mass of about 23 kDa. VEGF has some structural
similarities to platelet derived growth factor (PDGF), which is a
mitogen for connective tissue cells but not mitogenic for vascular
endothelial cells from large vessels.
[0003] The membrane-bound tyrosine kinase receptor, known as FLT,
was shown to be a VEGF receptor [DeVries, C. et al., (1992),
Science, 255, pp.989-991]. The FLT receptor specifically binds VEGF
which induces mitogenesis. Another form of the VEGF receptor,
designated KDR, is also known to bind VEGF and induce mitogenesis.
The partial cDNA sequence and nearly full length protein sequence
of KDR is known as well [Terman, B. I. et al., (1991) Oncogene 6,
pp. 1677-1683; Terman, B. I. et al., (1992) Biochem. Biophys. Res.
Comm. 187, pp.1579-1586].
[0004] Persistent angiogenesis may cause or exacerbate certain
diseases such as psoriasis, rheumatoid arthritis, hemangiomas,
angiofibromas, diabetic retinopathy and neovascular glaucoma. An
inhibitor of VEGF activity would be useful as a treatment for such
diseases and other VEGF-induced pathological angiogenesis and
vascular permeability conditions, such as tumor
vascularization.
SUMMARY OF THE DISCLOSURE
[0005] A naturally-occurring FLT messenger RNA (mRNA) was
identified and cloned from vascular endothelial cells. This mRNA is
shown to encode most of the extracellular, or soluble, portion of
the VEGF receptor, FLT. Soluble receptor molecules including forms
containing a C-terminal transmembrane region are also recombinantly
engineered for this and other VEGF receptors. These soluble
receptors, comprising truncated and modified forms are expressed in
recombinant host cells and have VEGF binding properties. The
soluble receptor proteins are useful as inhibitors of VEGF activity
since they will bind available VEGF preventing it from activating
its functional receptors on vascular endothelial cells and could
form non-functional heterodimers with full-length membrane anchored
VEGF receptors.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1--A schematic diagram of full length VEGF receptors
(FLT and KDR), the soluble VEGF receptors (sVEGF-RI and sVEGF-RII)
and the soluble receptors containing the C-terminal transmembrane
region (VEGF-RTMI and VEGF-RTMII) are shown with the protein
domains of each.
[0007] FIG. 2--The DNA sequence of the sVEGF-RI soluble VEGF
receptor/VEGF inhibitor is shown.
[0008] FIG. 3--The amino acid sequence of the sVEGF-RI soluble VEGF
receptor/VEGF inhibitor is shown.
[0009] FIG. 4--Demonstration that recombinant host cells express
sVEGF-RI is shown by the formation of high molecular weight
complexes of sVEGF-RI and [.sup.125I]VEGF and separated by size
exclusion chromatography.
[0010] FIG. 5--A 12.5% polyacrylamide electrophoretic gel is shown
which demonstrates the high degree of purity obtained for
sVEGF-RI.
[0011] FIG. 6--Cross-linked products of sVEGF-RI and
[.sup.125I]VEGF are shown at about 145 kDa, and at about 245
kDa.
[0012] FIG. 7A and 7B--Analysis of VEGF binding to sVEGF-RI (A) and
corresponding Scatchard plot (B).
[0013] FIG. 8--Inhibition of [.sup.125I]VEGF binding to HUVECs by
sVEGF-RI is demonstrated.
[0014] FIG. 9--Inhibition of VEGF-mediated mitogenesis on HUVECs is
shown using sVEGF-RI.
[0015] FIG. 10--The nucleotide sequence encoding sVEGF-RII is
shown.
[0016] FIG. 11--The amino acid sequence for sVEGF-RII is shown.
[0017] FIG. 12--The nucleotide sequence encoding VEGF-RTMII is
shown.
[0018] FIG. 13--The amino acid sequence for sVEGF-RTMII is
shown.
[0019] FIG. 14--The nucleotide sequence encoding sVEGF-RTMI is
shown.
[0020] FIG. 15--The amino acid sequence for sVEGF-RTMI is
shown.
[0021] FIG. 16--A diagram of pmFLT is shown.
[0022] FIG. 17--A diagram of pKDRA is shown.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0023] The present invention relates to cDNA encoding a soluble
VEGF receptor protein (sVEGF-R) which is isolated from VEGF
receptor producing cells or is recombinantly engineered from VEGF
receptor-encoding DNA. sVEGF-R, as used herein, refers to a protein
which can specifically bind to a vascular endothelial cell growth
factor without stimulating mitogenesis of vascular endothelial
cells.
[0024] The amino acid sequence of FLT is known, [Shibuya, M. et
al., (1990), Oncogene, 5, pp.519-524] and corresponds to the full
length cell-associated VEGF tyrosine kinase receptor. Other VEGF
receptors are known to exist. Other known VEGF receptors include,
but are not limited to KDR [Terman (1991), supra., and Terman
(1992), supra.]. Manmmalian cells capable of producing FLT, KDR and
other VEGF receptors include, but are not limited to, vascular
endothelial cells. Mammalian cell lines which produce FLT or KDR
and other VEGF receptors include, but are not limited to, human
endothelial cells. The preferred cells for the present invention
include human umbilical vein endothelial cells (HUVEC).
[0025] Other cells and cell lines may also be suitable for use to
isolate sVEGF-R cDNA. Selection of suitable cells may be done by
screening for sVEGF-R binding activity on cell surfaces, in cell
extracts or conditioned medium or by screening for gene expression
by PCR or hybridization. Methods for detecting soluble receptor
activity are well known in the art [Duan, D-S. R. et al., (1991)
J.Biol.Chem., 266, pp.413-418] and measure the binding of labelled
VEGF. Cells which possess VEGF binding activity in this assay may
be suitable for the isolation of sVEGF-R cDNA.
[0026] Full length FLT producing cells such as human HUVEC cells
(American Type Culture Collection, ATCC CRL 1730) [Hoshi, H. and
McKeehan, W. L., Proc. Natl. Acad. Sci. U.S.A., (1984) 81, pp.
6413-6417] are grown according to the recommended culture
conditions of the ATCC. Full length FLT, and KDR VEGF receptors as
well as extracellular region (sVEGF-RI and sVEGF-RII) and
extracellular region plus transmembrane region forms (VEGF-RTMI and
VEGF-RTMII) are shown in FIG. 1. The full length receptor has an
extracellular ligand binding region composed of about seven
immunoglobulin-like domains, a membrane spanning sequence
(transmembrane domain) and intracellular tyrosine kinase domains.
The inhibitory forms of this receptor, which are the subject of the
present invention, are also shown in FIG. 1 and lack the
intracellular kinase domains, and for some inhibitors, the
transmembrane sequence and the C-terminal most Ig-like
extracellular domain.
[0027] Any of a variety of procedures may be used to molecularly
clone sVEGF-R cDNA. These methods include, but are not limited to,
direct functional expression of the sVEGF-R gene following the
construction of an sVEGF-R-containing cDNA library in an
appropriate expression vector system.
[0028] Another method is to screen a sVEGF-R-containing cDNA
library constructed in a bacteriophage or plasmid shuttle vector
with a labelled oligonucleotide probe designed from the predicted
amino acid sequence of sVEGF-R. The preferred method consists of
screening a sVEGF-R-containing cDNA library constructed in a
bacteriophage or plasmid shuttle vector with a partial cDNA
encoding at least part of the full length FLT protein. This partial
cDNA is obtained by the specific PCR amplification of sVEGF-R DNA
fragments through the design of oligonucleotide primers from the
known sequence of the full length FLT-encoding DNA.
[0029] It is readily apparent to those skilled in the art that
other types of libraries, as well as libraries constructed from
other cells or cell types, may be useful for isolating
sVEGF-R-encoding DNA. Other types of libraries include, but are not
limited to, cDNA libraries derived from other cells or cell lines
other than HUVECs and genomic DNA libraries.
[0030] It is readily apparent to those skilled in the art that
suitable cDNA libraries may be prepared from cells or cell lines
which have sVEGF-R activity. The selection of cells or cell lines
for use in preparing a cDNA library to isolate sVEGF-R cDNA may be
done by first measuring secreted sVEGF-R activity using the VEGF
binding assay described fully herein.
[0031] Preparation of cDNA libraries can be performed by standard
techniques well known in the art. Well known cDNA library
construction techniques can be found for example, in Maniatis, T.,
Fritsch, E. F., Sambrook, J., Molecular Cloning: A Laboratory
Manual (Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.,
1982).
[0032] It is also readily apparent to those skilled in the art that
DNA encoding sVEGF-R may also be isolated from a suitable genomic
DNA library. Construction of genomic DNA libraries can be performed
by standard techniques well known in the art. Well known genomic
DNA library construction techiques can be found in Maniatis, T.,
Fritsch, E. F., Sambrook, J. in Molecular Cloning: A Laboratory
Manuel (Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.,
1982).
[0033] Another means of obtaining sVEGF-R molecules is to
recombinantly engineer them from DNA encoding the partial or
complete amino acid sequence of a VEGF receptor. Examples of other
VEGF receptors include, but are not limited to, KDR. Using
recombinant DNA techniques, DNA molecules are constructed which
encode at least a portion of the VEGF receptor capable of binding
VEGF without stimulating mitogenesis. Standard recombinant DNA
techniques are used such as those found in Maniatis, et al.,
supra.
[0034] Using one of the preferred methods of the present invention,
cDNA clones encoding sVEGF-R are isolated in a two-stage approach
employing polymerase chain reaction (PCR) based technology and cDNA
library screening. In the first stage, DNA oligonucleotides derived
from the extracellular domain sequence information from the known
full length FLT, KDR or other VEGF receptor is used to design
degenerate oligonucleotide primers for the amplification of
sVEGF-R-specific DNA fragments. In the second stage, these
fragments are cloned to serve as probes for the isolation of
complete sVEGF-R cDNA from a commercially available lambda gt10
cDNA library (Clontech) derived from HUVEC cells (ATCC CRL
1730).
[0035] These PCR derived products were used as hybridization probes
for screening a lambda gt10 cDNA library derived from HUVECs
(Clontech). Plating and plaque lifts of the library were performed
by standard methods (T. Maniatis, E. F. Fritsch, J. Sambrook,
Molecular Cloning: A Laboratory Manual (Cold Spring Harbor
Laboratory, Cold Spring Harbor, N.Y., 1982). The probes were
random-primed labelled with .sup.32P-dCTP to high specific activity
and a separate screening of the library (1.times.10.sup.6 plaques
per screen) was conducted with each probe. The probes were added to
hybridization buffer (50% formamide, 5.times. Denhardts,
6.times.SSC (1.times.SSC=0.15 M NaCl, 0.015 M
Na.sub.3citrate2H.sub.2O, pH 7.0), 0.1% SDS, 100 mg/ml salmon sperm
DNA) at 1.times.10.sup.6 cpm/ml.
[0036] Four positively hybridizing phage were detected using the
flt-specific probe. These positively hybridizing phage were
observed to be less than full length flt.
[0037] Two fit cDNA clones of about 2.0 kb and 2.7 kb in length
were subcloned into pGEM vectors (Promega) and bi-directionally
sequenced in their entirety by the chain termination method (Sanger
et al., (1977) P.N.A.S. USA, 74, pp. 5463-5467,) and shown to
contain a single open reading frame of about 569 amino acids.
Sequence analysis demonstrated that a portion of the 5' flt coding
region was missing from these clones. The remainder of the 5' end
was cloned using PCR and combined with the DNA of the clones
lacking the 5' end to yield a single open reading frame encoding
about 687 amino acids.
[0038] The sequence for the cDNA encoding flt-derived sVEGF-RI is
shown in Table 1, and was identified in clones 7 and 11. The
deduced amino acid sequence of sVEGF-RI from the cloned cDNA is
shown in Table 2. Inspection of the deduced amino acid sequence
reveals the presence of a single, large open reading frame of 687
amino acids. By comparison with amino acid sequence of the full
length FLT VEGF receptor, 31 amino acids are encoded at the
C-terminal end of the cDNA which are different from those of
FLT.
[0039] Using another of the preferred methods of the present
invention, DNA encoding sVEGF-R is constructed from a DNA sequence
encoding a VEGF receptor. For purposes of illustration, DNA
encoding the VEGF receptor known as KDR was utilized. Using the
receptor DNA sequence, a DNA molecule is constructed which encodes
the extracellular domain of the receptor, or the VEGF binding
domain only and is denoted sVEGF-RII. Restriction endonuclease
cleavage sites are identified within the receptor DNA and can be
utilized directly to excise the extracellular-encoding portion. In
addition, PCR techniques as described above may be utilized to
produce the desired portion of DNA. It is readily apparent to those
skilled in the art that other techniques, which are standard in the
art, may be utilized to produce sVEGF-R molecules in a manner
analagous to those described above. Such techniques are found, for
example, in Maniatis et al., supra.
[0040] Additional truncated forms of the VEGF receptor are
constructed which contain the transmembrane region. Retention of
the transmembrane may facilitate orientation of the inhibitor
molecule at the target cell surface. Examples of transmembrane
region containing inhibitor molecules include but are not limited
to those shown in FIG. 1. VEGF-RTMI and VEGF-RTMII, as shown in
FIG. 1, are FLT-related and KDR-related, respectively,
transmembrane region containing receptor inhibitors. Construction
of transmembrane region containing molecules, such as VEGF-RTMI and
VEGF-RTMII, is done by standard techniques known in the art
including but not limited to utilizing convenient restriction
endonuclease cleavage sites or PCR techniques as described herein.
It is readily understood by those skilled in the art that various
forms of the inhibitors of a VEGF receptor, as disclosed herein,
containing only the extracellular region or containing, in
addition, the transmembrane region may be constructed which have
substantially the same activity.
[0041] The cloned sVEGF-R cDNA obtained through the methods
described above may be recombinantly expressed by molecular cloning
into an expression vector containing a suitable promoter and other
appropriate transcription regulatory elements, and transferred into
prokaryotic or eukaryotic host cells to produce recombinant
sVEGF-R. Techniques for such manipulations are fully described in
Maniatis, T, et al., supra, and are well known in the art.
[0042] Expression vectors are defined herein as DNA sequences that
are required for the transcription of cloned copies of genes and
the translation of their mRNAs in an appropriate host. Such vectors
can be used to express eukaryotic genes in a variety of hosts such
as bacteria, bluegreen algae, fungal cells, yeast cells, plant
cells, insect cells and animal cells.
[0043] Specifically designed vectors allow the shuttling of DNA
between hosts such as bacteria-yeast or bacteria-animal or
bacteria-insect cells. An appropriately constructed expression
vector should contain: an origin of replication for autonomous
replication in host cells, selectable markers, a limited number of
useful restriction enzyme sites, a potential for high copy number,
and active promoters. A promoter is defined as a DNA sequence that
directs RNA polymerase to bind to DNA and initiate RNA synthesis. A
strong promoter is one which causes mRNAs to be initiated at high
frequency. Expression vectors may include, but are not limited to,
cloning vectors, modified cloning vectors, specifically designed
plasmids or viruses.
[0044] A variety of mammalian expression vectors may be used to
express recombinant sVEGF-R in mammalian cells. Commercially
available mammalian expression vectors which may be suitable for
recombinant sVEGF-R expression, include but are not limited to,
pMC1neo (Stratagene), pXT1 (Stratagene), pSG5 (Stratagene),
EBO-pSV2-neo (ATCC 37593) pBPV-1(8-2) (ATCC 37110),
pdBPV-MMTneo(342-12) (ATCC 37224), pRSVgpt (ATCC 37199), pRSVneo
(ATCC 37198), pSV2-dhfr (ATCC 37146), pUCTag (ATCC 37460), and
gZD35 (ATCC 37565).
[0045] DNA encoding sVEGF-R may also be cloned into an expression
vector for expression in a recombinant host cell. Recombinant host
cells may be prokaryotic or eukaryotic, including but not limited
to bacteria, yeast, mammalian cells including but not limited to
cell lines of human, bovine, porcine, monkey and rodent origin, and
insect cells including but not limited to drosophila, moth,
mosquito and armyworm derived cell lines. Cell lines derived from
mammalian species which may be suitable and which are commercially
available, include but are not limited to, CV-1 (ATCC CCL 70),
COS-1 (ATCC CRL 1650), COS-7 (ATCC CRL 1651), CHO-K1 (ATCC CCL 61),
3T3 (ATCC CCL 92), NIH/3T3 (ATCC CRL 1658), HeLa (ATCC CCL 2),
C1271 (ATCC CRL 1616), BS-C-1 (ATCC CCL 26) and MRC-5 (ATCC CCL
171). Insect cell lines which may be suitable and are commercially
available include but are not limited to 3M-S (ATCC CRL 8851) moth
(ATCC CCL 80) mosquito (ATCC CCL 194 and 195; ATCC CRL 1660 and
1591) and armyworm (Sf9, ATCC CRL 1711).
[0046] The expression vector may be introduced into host cells via
any one of a number of techniques including but not limited to
transformation, transfection, liposome or protoplast fusion, and
electroporation. The expression vector-containing cells are
clonally propagated and individually analyzed to determine whether
they produce sVEGF-R protein. Identification of sVEGF-R expressing
host cell clones may be done by several means, including but not
limited to immunological reactivity with anti-sVEGF-R antibodies,
binding to radiolabelled VEGF, and the presence of host
cell-secreted sVEGF-R activity.
[0047] Expression of sVEGF-R DNA may also be performed using in
vitro produced synthetic mRNA. Synthetic mRNA can be efficiently
translated in various cell-free systems, including but not limited
to wheat germ extracts and reticulocyte extracts, as well as
efficiently translated in cell based systems, including but not
limited to microinjection into frog oocytes, with microinjection
into frog oocytes being preferred.
[0048] Levels of sVEGF-R protein produced by host cells may be
quantitated by immunoaffinity and/or ligand affinity techniques.
sVEGF-R-specific affinity beads or sVEGF-R-specific antibodies are
used to isolate .sup.35S-methionine labelled or unlabelled sVEGF-R
protein. Labelled sVEGF-R protein is analyzed by SDS-PAGE.
Unlabelled sVEGF-R protein is detected by Western blotting, ELISA
or RIA assays employing sVEGF-R specific antibodies, or by ligand
blotting with labelled VEGF.
[0049] Following expression of sVEGF-R in a recombinant host cell,
sVEGF-R protein may be recovered to provide sVEGF-R in active form,
capable of binding VEGF without stimulating mitogenesis. Several
sVEGF-R purification procedures are available and suitable for use.
sVEGF-R may be purified from cell lysates and extracts, or from
conditioned culture medium, by various combinations of, or
individual application of salt fractionation, ion exchange
chromatography, size exclusion chromatography, hydroxylapatite
adsorption chromatography, reversed phase chromatography, heparin
sepharose chromatography, VEGF ligand affinity chromatography, and
hydrophobic interaction chromatography.
[0050] In addition, recombinant sVEGF-R can be separated from other
cellular proteins by use of an immuno-affinity column made with
monoclonal or polyclonal antibodies specific for full length
sVEGF-R, or polypeptide fragments of sVEGF-R.
[0051] Identification of sVEGF-RI--In an attempt to clone the VEGF
receptor cDNA (flt) a HUVEC lgt10 cDNA library was screened with a
DNA probe derived from the extracellular domain of the membrane
bound or full length form of this receptor as shown in FIG. 1. Four
incomplete clones, all lacking various lengths of 5' coding
sequence, were isolated from screening a total of 1.times.10.sup.6
plaques. Two of these isolates represent partial clones that were
identical to full length fit, one of which contained the complete
3' coding region of the form described by Shibuya et al., supra.
The other two clones were identical to full length fit up to base
pair number 2219 (Table 1 and FIG. 2) where they then diverged from
full length fit. These clones (clone 7 and 11) coded for an
additional unique 31 amino acids before the open reading frame is
terminated by a TAA codon (Table 2 and FIG. 3).
[0052] Clone 7 and 11 coded for a protein with a predicted
molecular mass of about 75 kDa containing 12 putative N-linked
glycosylation sites. This version of the receptor was missing the
transmembrane and intracellular kinase domains and thus coded for a
natural soluble form of the VEGF receptor (sVEGF-RI). Further, the
protein molecule predicted by sVEGF-RI has only the first six
Ig-like domains, missing the one closest to the transmembrane
sequence (FIG. 1). The 31 amino acids at the C-terminal end of
sVEGF-RI contain two cysteine residues, but does not resemble an Ig
domain.
[0053] Expression of sVEGF-RI in Sf9 cells--To analyze the binding
and biological properties of this form of the receptor, the protein
was expressed using a baculovirus expression system. Clone 7 was
missing about 350 base pairs of coding sequence at the 5' end. This
region was cloned by PCR using the primers described above and in
Example 1. A clone containing the complete coding region of
sVEGF-RI was constructed by combining the 5' PCR fragment with
sVEGF-RI clone 7 which overlapped at a Sacd site. The 5' EcoRI site
was then changed to a BamHI site and the full length sVEGF-RI was
cloned into pBluebac III (Invitrogen) as a BamHI/BamHI fragment. A
recombinant baculovirus P-3 stock containing the sVEGF-RI gene 3'
in relation to the polyhedrin promoter was then prepared as
described herein.
[0054] Culture media from small scale infections were tested for
the ability to form high molecular weight complexes with
[.sup.125I]VEGF. The labeled ligand and culture media from the
baculovirus infected cells were combined and incubated. The
reactions were then analyzed by size exclusion chromatography. When
the wild-type infected culture medium was mixed with the
radioactive ligand (FIG. 4) a single radioactive peak was observed.
However, when the sVEGF-RI infected culture medium was used, a high
molecular weight complex was formed, as evident by the appearance
of a second peak in this reaction eluting near the void volume of
the column. This experiment showed that the natural soluble form of
the FLT VEGF receptor, sVEGF-RI, forms a high molecular weight
complex with VEGF.
[0055] The recombinantly produced sVEGF-R is purified from the
recombinant host cell extracts or cell culture fluid using
heparin-sepharose column chromatography which specifically binds
the sVEGF-R protein. The heparin-sepharose bound VEGF-R column is
washed using a suitable buffer containing between 0.1M and 0.6M
NaC1 which removes contaminating proteins without significant loss
of sVEGF-R. The sVEGF-R is eluted from the heparin-sepharose column
using a suitable buffer containing about 1M NaC1, yielding
substantially purified sVEGF-R.
[0056] Binding of the sVEGF-RI to VEGF--The binding of
.sup.125I-labelled VEGF to sVEGF-RI was characterized by
crosslinking, and by complex formation with sVEGF-RI absorbed to 96
well plates.
[0057] The crosslinked products are shown in FIG. 6. The sVEGF-RI
was cross-linked to [.sup.125I]VEGF (lane 1); in the presence of
unlabelled VEGF (lane 2) and unlabelled bFGF (lane 3). Two high
molecular weight bands (about 145 kDa and 245 kDa) were formed in
the sVEGF-RI and [.sup.125I]VEGF containing reaction, and in the
sVEGF-RI and [.sup.125I]VEGF plus an excess of unlabelled bFGF
reaction. The two high molecular weight bands were not present when
sVEGF-RI was incubated with [.sup.125I]VEGF plus an excess of
unlabelled VEGF, demonstrating the specificity of sVEGF-RI for
VEGF, and the ability of sVEGF-RI to form a dimer. The 145 kDa band
is presumably a crosslinked complex containing one receptor
molecule (about 100 kDa) and a VEGF dimer (about 46 kDa). As shown
in FIG. 6 complexes containing two receptor molecules (about 245
kDA) were also observed. This suggests that each VEGF dimer can
bind one or two receptor molecules and that the soluble form of the
VEGF receptor may undergo ligand-induced dimerization.
[0058] The affinity of sVEGF-RI for VEGF was evaluated by absorbing
sVEGF-RI to the surface of a 96 well plate, followed by blocking
the nonspecific sites with 0.5% gelatin. Variable amounts of
labeled ligand were added to each well. These results demonstrate
that sVEGF-RI binds VEGF with high affinity with an apparent Kd of
about 20 pM (FIG. 7). Since the soluble form of the receptor is
missing the Ig domain closest to the transmembrane spanning region,
this domain is not required for ligand binding.
[0059] The sVEGF-RI is shown to inhibit binding of VEGF to HUVECs
by incubating cultured HUVECs with [.sup.125I]VEGF and various
amounts of sVEGF-RI. Following incubation, the cells are washed to
remove unbound [.sup.125I]VEGF. The cells are then solubilized and
the amount of cell-associated 125I is determined by gamma counter,
which demonstrates the amount of [.sup.125I]VEGF which was capable
of binding to the cellular VEGF receptor in the presence of
sVEGF-RI. Using this method, it is demonstrated that sVEGF-RI was
capable of inhibiting [.sup.125I]VEGF binding to HUVECs VEGF
receptor (see FIG. 8).
[0060] Since sVEGF-RI was able to inhibit VEGF binding to cell
receptors, it was then determined that sVEGF-RI could inhibit VEGF
induced mitogenesis. Cells are preincubated with sVEGF-RI and then
incubated with VEGF in the presence of [.sup.3H]thymidine.
Following incubation, the amount of cellular DNA-incorporated
[.sup.3H]thymidine is measured which indicates whether VEGF has
induced mitogenesis and caused [.sup.3H]thymidine to be
incorporated into cellular DNA. The presence of sVEGF-RI inhibits
the ability of VEGF to stimulate mitogenesis as shown in FIG.
9.
[0061] The inhibitor of the present invention can be used for the
inhibition of VEGF activity. The inhibitor can be used either
topically or intravascularly. For topical applications the
formulation would be applied directly at a rate of about 10 ng to
about 1 mg/cm.sup.2/day. For intravaneous applications, the
inhibitor is used at a rate of about 1 mg to about 10 mg/kg/day of
body weight. For internal use, the formulation may be released
directly into the region to be treated either from implanted slow
release polymeric material or from slow release pumps or repeated
injections. The release rate in either case is about 100 ng to
about 100 mg/day/cm.sup.3.
[0062] For non-topical application the VEGF inhibitor is
administered in combination with pharmaceutically acceptable
carriers or diluents such as phosphate buffer, saline, phosphate
buffered saline, Ringer's solution, and the like, in a
pharmaceutical composition, according to standard pharmaceutical
practice. For topical application, various pharmaceutical
formulations are useful for the administration of the active
compound of this invention. Such formulations include, but are not
limited to, the following: ointments such as hydrophilic petrolatum
or polyethylene glycol ointment; pastes which may contain gums such
as xanthan gum; solutions such as alcoholic or aqueous solutions;
gels such as aluminum hydroxide or sodium alginate gels; albumins
such as human or animal albumins; collagens such as human or animal
collagens; celluloses such as alkyl celluloses, hydroxy alkyl
celluloses and alkylhydroxyalkyl celluloses, for example
methylcellulose, hydroxyethyl cellulose, carboxymethyl cellulose,
hydroxypropyl methylcellulose, and hydroxypropyl cellulose;
polyoxamers such as Pluronic.RTM. Polyols exemplified by
Pluronic.RTM. F-127; tetronics such as tetronic 1508; and alginates
such as sodium alginate.
[0063] The following examples are provided as illustrative of the
present invention without, however, limiting the same thereto.
EXAMPLE 1
[0064] Cloning flt-related sVEGF-RI--A 580 base pair DNA probe for
flt was obtained by PCR of the HUVEC phage library using the
primers 5' GCACCTTGGTTGTGGCTGAC 3' (SEQ. ID. No.: 1) and 5'
TGGAATTCGTGCTGCTTCCTGGTCC 3' (SEQ. ID. No.: 2). The resulting DNA
fragment was cloned into pGEM3Z as a XbaI/EcoRI fragment. The probe
was prepared by the random priming method [Feinberg, A. P. and
Vogelstein, B., (1983) Anal.Biochem., 132, pp.6-13] using the
megaprime kit (Amersham) at a specific activity of 1.times.10.sup.7
cpm/ng. The HUVEC cDNA library was plated at a density of
5.times.10.sup.4 plaques/150 cm plate then about 1.times.10.sup.6
plaques were screened by hybridization as previously described
[Maniatis, T. et al., supra]. Briefly, following prehybridization
at 42.degree. C. for 2 hours in 50% formamide, 5.times.SSC,
5.times. Denhardt's solution, 0.1% SDS, 100 mg/ml salmon sperm DNA
(hybridization buffer) the filters were hybridized with the probe
for 16 hours at 42.degree. C. in hybridization buffer. The filters
were washed one time for 15 min at room temperature in 2.times.SSC
then three times at 55.degree. C. in 0.1.times.SSC. Four positive
plaques were identified and rescreened two additional times to
obtain homogeneous isolates. Inserts were cloned into pGEM3Z for
DNA sequence analysis. Two of these clones were identified which
contained less than the full length flt coding region. DNA sequence
analysis showed that these clones lacked the 5' coding region of
flt. The DNA sequence is shown in Table 1 and FIG. 2, and the
deduced amino acid sequence is shown in Table 2 and FIG. 3. The 5'
end of fit was cloned by PCR using the primers 5'
GGAATTCCGCGCTCACCATGGTCAGC 3' (SEQ.ID.NO.:3) and 5'
TTTGAATTCACCCGGCAGGGAATGACG 3' (SEQ.ID.NO.:4). The PCR fragment
generated with this set of primers was cloned into fit clone 7 as
an EcoRI/Sacl fragment. TABLE-US-00001 TABLE 1
GCGGACACTCCTCTCGGCTCCTCCCCGGCAGCGG (SEQ. ID. NO.:5)
CGGCGGCTCGGAGCGGGCTCCGGGGCTCGGGTGC
AGCGGCCAGCGGGCCTGGCGGCGAGGATTACCCG
GGGAAGTGGTTGTCTCCTGGCTGGAGCCGCGAGA
CGGGCGCTCAGGGCGCGGGGCCGGCGGCGGCGAA
CGAGAGGACGGACTCTGGCGGCCGGGTCGTTGGC
CGGGGGAGCGCGGGCACCGGGCGAGCAGGCCGCG TCGCGCTCACC ATG GTC AGC TAC TGG
GAC ACC GGG GTC CTG CTG TGC GCG CTG CTC AGC TGT CTG CTT CTC ACA GGA
TCT AGT TCA GGT TCA AAA TTA AAA GAT CCT GAA CTG AGT TTA AAA GGC ACC
CAG CAC ATC ATG CAA GCA GGC CAG ACA CTG CAT CTC CAA TGC AGG GGG GAA
GCA GCC CAT AAA TGG TCT TTG CCT GAA ATG GTG AGT AAG GAA AGC GAA AGG
CTG AGC ATA ACT AAA TCT GCC TGT GGA AGA AAT GGC AAA CAA TTC TGC AGT
ACT TTA ACC TTG AAC ACA GCT CAA GCA AAC CAC ACT GGC TTC TAC AGC TGC
AAA TAT CTA GCT GTA CCT ACT TCA AAG AAG AAG GAA ACA GAA TCT GCA ATC
TAT ATA TTT ATT AGT GAT ACA GGT AGA CCT TTC GTA GAG ATG TAC AGT GAA
ATC CCC GAA ATT ATA CAC ATG ACT GAA GGA AGG GAG CTC GTC ATT CCC TGC
CGG GTT ACG TCA CCT AAC ATC ACT GTT ACT TTA AAA AAG TTT CCA CTT GAC
ACT TTG ATC CCT GAT GGA AAA CGC ATA ATC TGG GAC AGT AGA AAG GGC TTC
ATC ATA TCA AAT GCA ACG TAC AAA GAA ATA GGG CTT CTG ACC TGT GAA GCA
ACA GTC AAT GGG CAT TTG TAT AAG ACA AAC TAT CTC ACA CAT CGA CAA ACC
AAT ACA ATC ATA GAT GTC CAA ATA AGC ACA CCA CGC CCA GTC AAA TTA CTT
AGA GGC CAT ACT CTT GTC CTC AAT TGT ACT GCT ACC ACT CCC TTG AAC ACG
AGA GTT CAA ATG ACC TGG AGT TAC CCT GAT GAA AAA AAT AAG AGA GCT TCC
GTA AGG CGA CGAATT GAC CAA AGC AAT TCC CAT GCC AAC ATA TTC TAC AGT
GTT CTTACT ATT GAC AAA ATG CAG AAC AAA GAC AAA GGA CTT TAT ACT
TGTCGT GTA AGG AGT GGA CCA TCA TTC AAA TCT GTT AAC ACC TCA GTGCAT
ATA TAT GAT AAA GCA TTC ATC ACT GTG AAA CAT CGA AAA CAGCAG GTG CTT
GAA ACC GTA GCT GGC AAG CGG TCT TAC CGG CTC TCTATG AAA GTG AAG GCA
TTT CCC TCG CCG GAA GTT GTA TGG TTA AAAGAT GGG TTA CCT GCG ACT GAG
AAA TCT GCT CGC TAT TTG ACT CGT GGC TAC TCG TTA ATT ATC AAG GAC GTA
ACT GAA GAG GAT GCA GGG AAT TAT ACA ATC TTG CTG AGC ATA AAA CAG TCA
AAT GTG TTT AAA AAC CTC ACT GCC ACT CTA ATT GTC AAT GTG AAA CCC CAG
ATT TAC GAA AAG GCC GTG TCA TCG TTT CCA GAC CCG GCT CTC TAC CCA CTG
GGC AGC AGA CAA ATC CTG ACT TGT ACC GCA TAT GGT ATC CCT CAA CCT ACA
ATC AAG TGG TTC TGG CAC CCC TGT AAC CAT AAT CAT TCC GAA GCA AGG TGT
GAC TTT TGT TCC AAT AAT GAA GAG TCC TTT ATC CTG GAT GCT GAC AGC AAC
ATG GGA AAC AGA ATT GAG AGC ATC ACT CAG CGC ATG GCA ATA ATA GAA GGA
AAG AAT AAG ATG GCT AGC ACC TTG GTT GTG GCT GAC TCT AGA ATT TCT GGA
ATC TAC ATT TGC ATA GCT TCC AAT AAA GTT GGG ACT GTG GGA AGA AAC ATA
AGC TTT TAT ATC ACA GAT GTG CCA AAT GGG TTT CAT GTT AAC TTG GAA AAA
ATG CCG ACG GAA GGA GAG GAC CTG AAA CTG TCT TGC ACA GTT AAC AAG TTC
TTA TAC AGA GAC GTT ACT TGG ATT TTA CTG CGG ACA GTT AAT AAC AGA ACA
ATG CAC TAC AGT ATT AGC AAG CAA AAA ATG GCC ATC ACT AAG GAG CAC TCC
ATC ACT CTT AAT CTT ACC ATC ATG AAT GTT TCC CTG CAA GAT TCA GGC ACC
TAT GCC TGC AGA GCC AGG AAT GTA TAC ACA GGG GAA GAA ATC CTC CAG AAG
AAA GAA ATT ACA ATC AGA GGT GAG CAC TGC AAC AAA AAG GCT GTT TTC TCT
CGG ATC TCC AAA TTT AAA AGC ACA AGG AAT GAT TGT ACC
ACACAAAGTAATGTAAAACATTAAAG GACTCATTAAAAAGTAACAGTTGTCTCATATCAT
CTTGATTTATTGTCACTGTTGCTAACTTTCAGGC
TCGGAGGAGATGCTCCTCCCAAAATGAGTTCGGA
GATGATAGCAGTAATAATGAGACCCCCGGGCTCC
AGCTCTGGGCCCCCCATTCAGGCCGAGGGGGCTG
CTCCGGGGGGCCGACTTGGTGCACGTTTGGATTT
GGAGGATCCCTGCACTGCCTTCTCTGTGTTTGTT
GCTCTTGCTGTTTTCTCCTGCCTGATAAACAACA
ACTTGGGATGATCCTTTCCATTTTGATGCCAACC
TCTTTTTATTTTTAAGCGGCGCCCTATAGT
[0065] TABLE-US-00002 TABLE 2 Met Val Ser Tyr Trp Asp Thr Gly (SEQ.
ID. NO.:6) Val Leu Leu Cys Ala Leu Leu Ser Cys Leu Leu Leu Thr Gly
Ser Ser Ser Gly Ser Lys Leu Lys Asp Pro Glu Leu Ser Leu Lys Gly Thr
Gln His Ile Met Gln Ala Gly Gln Thr Leu His Leu Gln Cys Arg Gly Glu
Ala Ala His Lys Trp Ser Leu Pro Glu Met Val Ser Lys Glu Ser Glu Arg
Leu Ser Ile Thr Lys Ser Ala Cys Gly Arg Asn Gly Lys Gln Phe Cys Ser
Thr Leu Thr Leu Asn Thr Ala Gln Ala Asn His Thr Gly Phe Tyr Ser Cys
Lys Tyr Leu Ala Val Pro Thr Ser Lys Lys Lys Glu Thr Glu Ser Ala Ile
Tyr Ile Phe Ile Ser Asp Thr Gly Arg Pro Phe Val Glu Met Tyr Ser Glu
Ile Pro Glu Ile Ile His Met Thr Glu Gly Arg Glu Leu Val Ile Pro Cys
Arg Val Thr Ser Pro Asn Ile Thr Val Thr Leu Lys Lys Phe Pro Leu Asp
Thr Leu Ile Pro Asp Gly Lys Arg Ile Ile Trp Asp Ser Arg Lys Gly Phe
Ile Ile Ser Asn Ala Thr Tyr Lys Glu Ile Gly Leu Leu Thr Cys Glu Ala
Thr Val Asn Gly His Leu Tyr Lys Thr Asn Tyr Leu Thr His Arg Gln Thr
Asn Thr Ile Ile Asp Val Gln Ile Ser Thr Pro Arg Pro Val Lys Leu Leu
Arg Gly His Thr Leu Val Leu Asn Cys Thr Ala Thr Thr Pro Leu Asn Thr
Arg Val Gln Met Thr Trp Ser Tyr Pro Asp Gln Lys Asn Lys Arg Ala Ser
Val Arg Arg Arg Ile Asp Gln Ser Asn Ser His Ala Asn Ile Phe Tyr Ser
Val Leu Thr Ile Asp Lys Met Gln Asn Lys Asp Lys Gly Leu Tyr Thr Cys
Arg Val Arg Ser Gly Pro Ser Phe Lys Ser Val Asn Thr Ser Val His Ile
Tyr Asp Lys Ala Phe Ile Thr Val Lys His Arg Lys Gln Gln Val Leu Glu
Thr Val Ala Gly Lys Arg Ser Tyr Arg Leu Ser Met Lys Val Lys Ala Phe
Pro Ser Pro Gln Val Val Trp Leu Lys Asp Gly Leu Pro Ala Thr Gln Lys
Ser Ala Arg Tyr Leu Thr Arg Gly Tyr Ser Leu Ile Ile Lys Asp Val Thr
Gln Gln Asp Ala Gly Asn Tyr Thr Ile Leu Leu Ser Ile Lys Gln Ser Asn
Val Phe Lys Asn Leu Thr Ala Thr Leu Ile Val Asn Val Lys Pro Gln Ile
Tyr Gln Lys Ala Val Ser Ser Phe Pro Asp Pro Ala Leu Tyr Pro Leu Gly
Ser Arg Gln Ile Leu Thr Cys Thr Ala Tyr Gly Ile Pro Gln Pro Thr Ile
Lys Trp Phe Trp His Pro Cys Asn His Asn His Ser Gln Ala Arg Cys Asp
Phe Cys Ser Asn Asn Gln Gln Ser Phe Ile Leu Asp Ala Asp Ser Asn Met
Gly Asn Arg Ile Gln Ser Ile Thr Gln Arg Met Ala Ile Ile Gln Gly Lys
Asn Lys Met Ala Ser Thr Leu Val Val Ala Asp Ser Arg Ile Ser Gly Ile
Tyr Ile Cys Ile Ala Ser Asn Lys Val Gly Thr Val Gly Arg Asn Ile Ser
Phe Tyr Ile Thr Asp Val Pro Asn Gly Phe His Val Asn Leu Gln Lys Met
Pro Thr Gln Gly Gln Asp Leu Lys Leu Ser Cys Thr Val Asn Lys Phe Leu
Tyr Arg Asp Val Thr Trp Ile Leu Leu Arg Thr Val Asn Asn Arg Thr Met
His Tyr Ser Ile Ser Lys Gln Lys Met Ala Ile Thr Lys Gln His Ser Ile
Thr Leu Asn Leu Thr Ile Met Asn Val Ser Leu Gln Asp Ser Gly Thr Tyr
Ala Cys Arg Ala Arg Asn Val Tyr Thr Gly Gln Gln Ile Leu Gln Lys Lys
Gln Ile Thr Ile Arg Gly Gln His Cys Asn Lys Lys Ala Val Phe Ser Arg
Ile Ser Lys Phe Lys Ser Thr Arg Asn Asp Cys Thr Thr Gln Ser Asn Val
Lys His .cndot..cndot..cndot.
EXAMPLE 2
[0066] Expression of sVEGF-RI in Sf9 insect cells--The full length
sequence encoding sVEGF-RI was cloned as an EcoRI/BamHI fragment
into pGEM3Z. The EcoRI site was then modified to a BamHI site and
cloned into pBlueBac III 3' of the polyhedrin promoter (psFLThlue).
This plasmid was transfected into Sf9 armyworm cells using
liposomes. After 48 hours the medium from the transfected cells
which contains recombinant polyhedrin virus particles, was
harvested. Dilutions (10.sup.3-10.sup.4 fold) of the virus were
prepared and plaque purified in soft agar containing 150 mg/ml
5-bromo-4-chloro-3-indolyl-.beta.-D-galactoside. Recombinant
plaques were identified by blue color and used to infect Sf9 cells
(5.times.10.sup.5 cells/well) in 12 well plates. Medium (100 ml)
from polyhedrin minus infections was used to prepare P-2 viral
stocks by infecting 2.5.times.10.sup.6 cells in a T-25 flask. Large
scale high titer P-3 viral stocks were then prepared by infecting
Sf9 cells (500 ml at 2.times.10.sup.6 cells/ml) with 5 ml of the
P-2 stock then incubating at 27.degree. C. for 5-6 days and the
medium was harvested by centrifugation. Protein expression was
accomplished by infecting cells at a density of
2-2.5.times.10.sup.6 cells/ml with a multiplicity of infection of
5-10. Twenty four hours after infection the cells were changed to a
serum free medium (SF900II, Gibco BRL), incubated for an additional
48 hours and the medium was collected. This conditioned medium
contains the recombinantly expressed sVEGF-RI protein.
EXAMPLE 3
[0067] Iodination of VEGF and PIGF--.sup.125I-labeled human
recombinant VEGF was prepared by the chloramine T method (Hunter,
W. M. and Greenwood, F. C., (1962) Nature (London), 194, pp.
495-496). Briefly, 1 mg of VEGF in 30% acetonitrile/0.1%
trifluroacetic acid was adjusted to pH 7.1 by the addition of 1/3
volume of 0.4 M sodium phosphate buffer, pH 7.1. Freshly dissolved
chloramine T (4 ml of a 2 mg/ml stock in 0.1 M sodium phosphate
buffer, pH 7.1) was added to the VEGF solution and reacted for 45
seconds at room temperature (total volume of 150 ml). The reaction
was stopped by the addition of 50 ml of 10 mM KI and 50 ml of 2
mg/ml meta bisufite. The labeled ligand was separated from the free
.sup.125I by gel filtration on a 0.7.times.15 cm Sephadex G-25
column equilibrated in PBS with 1 mg/ml gelatin. Fractions were
counted in a Packard g counter, aliquoted and stored at -70.degree.
C. VEGF was labeled to a specific activity of 5.times.10.sup.5 to
1.times.10.sup.6 cpm/ng. Recombinant human P1GF was iodinated by
the chloramine-T method as described herein, to specific activity
between approximately 3.times.10.sup.5-9.times.10.sup.5 cpm/ng.
After iodination, PlGF was stored at 4.degree. C. in PBS containing
1 mg/ml gelatin.
[0068] Gel Filtration Chromatography--Receptor-ligand complex was
formed by incubating 10 ml of .sup.125I-labeled VEGF (10.sup.5 cpm)
with 100 ml of either wild-type or baculovirus sVEGF-RI-containing,
infected Sf9 cell culture medium overnight at room temperature. The
reaction products were separated on a Sephacryl S200 gel filtration
column (0.7.times.25 cm) equilibrated in PBS, 1 mg/ml gelatin, at a
flow rate of 15 ml/hr. Fractions (0.75 ml) were collected and
analyzed in a g counter. Receptor-ligand complexes pass quickly
through the column while the free labelled VEGF passes through more
slowly. The results of this experiment shown in FIG. 4 demonstrate
the formation of a high molecular weight complex between labelled
VEGF and sVEGF-RI protein. This shows that sVEGF-RI binds VEGF.
[0069] Crosslinking--Purified sVEGF-RI (1-10 ng) was added to 25 ml
of binding buffer (Dulbecco's Modified Eagle's medium (DME), 25 mM
HEPES, pH 7.5, 0.3% gelatin), and 1.times.10.sup.5 cpm of
[.sup.125I]-VEGF was added (FIG. 6, lane 1) with either 200 ng of
unlabelled VEGF (lane 2) or bFGF (lane 3), then incubated 2 to 16
hours at room temperature. Bis(sulfosuccinimidyl)suberate (Pierce)
crosslinker was added to a final concentration of 1 mM. The
reaction was stopped after 15 min by the addition of boiling SDS
PAGE sample buffer. The crosslinked products were separated by SDS
PAGE on a 7.5% acrylamide gel and analyzed either by
autoradiography or a phosphoimager. The results are shown in FIG. 6
and demonstrate that sVEGF-RI binds labelled VEGF by the appearance
of two bands of about 145 kDa and 245 kDa. The 145 kDa band
consists of one sVEGF-RI molecule and one VEGF molecule (Monomer,
M.). The 245 kDa band apparently consists of two sVEGF-RI molecules
and one VEGF dimer (D). Free VEGF ligand (L) dimers migrated at
about 45 kDA.
[0070] Purified Ex-KDR and sFLT were each allowed to bind either
[.sup.125I]VEGF or [.sup.125I]PlGF at 25.degree. C. for 1 hr in a
final volume of 25 .mu.l in binding buffer (10 mM Hepes, pH 7.4,
0.01% BSA, 100 mM NaCl) with or without an excess of the
appropriate unlabeled ligand. Competition binding was accomplished
by incubation in the presence of various concentrations of
unlabeled VEGF (0.1-400 nM). The reactions were then crosslinked
with 1 mM BS.sup.3 at 25.degree. C. for 15 min followed by the
addition of boiling Laemmli sample buffer (10). The crosslinked
products were analyzed by SDS/7.5% PAGE and the complexes were
visualized using a Phospholmager (Molecular Dynamics, Sunnyvale,
Calif.). In the competition crosslinking experiments the amount of
radioactivity contained in the Ex-KDR/[.sup.125I]VEGF complex as
well as the uncomplexed [.sup.125I]VEGF were quantified using the
Phospholmager.
[0071] Binding assay--The binding of sVEGF-RI to VEGF was analyzed
using a 96 well plate assay as described by Duan, D-S. R. et al.,
supra. Briefly, sVEGF-RI, 50 to 200 ml partially purified by Mono Q
chromatography (Pharmacia), was diluted to 10 ml in 25 mM TRIS, pH
7.4, 100 mM NaCl, 20 mM NH.sub.4HCO.sub.3. Aliquots (100 ml) were
absorbed to the surface of a 96 well plate for 18 hours at
4.degree. C., the plates were then washed twice with blocking
buffer (DME, 25 mM HEPES, pH 7.5, 0.5% gelatin) and the nonspecific
sites were blocked in the same buffer for 6 hours at 4.degree. C.
The plate was then washed twice in binding buffer. Various amounts
of [.sup.125I]VEGF were added to the wells in a final volume of 100
ml/well and incubated for 2 hours at room temperature. The wells
were washed three times with 100 ml of binding buffer, the bound
protein was solubilized with 100 ml of 1% SDS, 0.5% BSA and counted
in a g counter. The results, shown in FIG. 7, were analyzed by the
method of Scatchard [Scatchard, G., (1949) Ann. N.Y. Acad. Sci.,
51, pp. 660-672]. The analysis demonstrates that sVEGF-RI retains
high affinity binding for VEGF with a Kd value of about 20 pM. This
clearly demonstrates that sVEGF-RI, lacking the transmembrane
region and adjacent Ig-like domain, binds VEGF with high affinity
and that these regions are not required for VEGF binding.
[0072] Purified Ex-KDR and sFLT were each allowed to bind either
[.sup.125I]VEGF or [.sup.125I]PlGF at 25.degree. C. for 1 hour in a
final volume of 25 .mu.l in binding buffer (10 mM Hepes, pH 7.4,
0.01% BSA, 100 mM NaCl) with or without an excess of the
appropriate unlabeled ligand. Competition binding was accomplished
by incubation in the presence of various concentrations of
unlabeled VEGF (0.1-400 nM). The reactions were then crosslinked
with 1 mM BS.sup.3 at 25 .degree. C. for 15 min followed by the
addition of boiling Laenmmli sample buffer. The crosslinked
products were analyzed by SDS/7.5% PAGE and the complexes were
visualized using a Phospholmager (Molecular Dynamics, Sunnyvale,
Calif.). In the competition crosslinking experiments the amount of
radioactivity contained in the Ex-KDR/[.sup.125I]VEGF complex as
well as the uncomplexed [.sup.125I]VEGF were quantified using the
Phospholmager.
[0073] To determine if sFLT and Ex-KDR bind VEGF and PlGF with high
affinity, purified sFLT and Ex-KDR were each incubated with either
[.sup.125I]VEGF or [.sup.125I]PlGF, covalently crosslinked and high
molecular mass complexes were resolved by SDS/PAGE. sFLT formed
high molecular mass complexes with both VEGF and PlGF whereas
Ex-KDR formed complexes with VEGF but not with PlGF. The positions
of the monomer (one VEGF dimer bound to one receptor molecule) and
dimer (one VEGF dimer bound to two receptor molecules) were as
expected. These radiolabeled complexes were competed by an excess
of the same unlabeled VEGF or PlGF and thus are specific. PlGF was
able to compete for VEGF binding to the sFLT receptor and VEGF
competes for PIGF binding to this receptor. PlGF was not able to
compete for [.sup.125I]VEGF binding to Ex-KDR.
[0074] The affinity of VEGF for Ex-KDR was determined by a
crosslinking competition binding assay since the Ex-KDR receptor
binds poorly to 96 well plates. A constant amount of
[.sup.125I]VEGF was bound to Ex-KDR in the presence of increasing
concentrations of unlabeled VEGF. The concentration of unlabeled
VEGF required to displace 50% of the total [.sup.125I]VEGF binding
is approximately 1 nM, which is similar to the apparent K.sub.d for
the membrane form of KDR.
[0075] Competition between PlGF and VEGF for binding to sFLT
[0076] Competitive binding of VEGF and PlGF to sFLT was analyzed by
the 96 well plate binding assay. A constant amount of either
[.sup.125I]VEGF or [.sup.125I]PlGF was bound to immobilized sFLT in
the presence of increasing amounts of either unlabeled VEGF or
PlGF. In comparison, 50% of the binding of [.sup.125I]PlGF to sFLT
was displaced by only 10 pM of VEGF. Approximately 110 pM of
unlabeled PlGF displaced 50% of [.sup.125I]PlGF binding to sFLT in
agreement with saturation binding experiments. However, an
approximately 5-fold higher concentration of PIGF (.about.550 pM)
was required to displace 50% of the [.sup.125I]VEGF binding to
sFLT. These data indicate that VEGF and PlGF compete for the same
site on sFLT at which VEGF binds with .about.4-fold higher affinity
than PlGF. Crosslinking competition experiments with sFLT gave
similar results.
[0077] Here we show that VEGF binds to the extracellular domains of
both FLT and KDR with high affinity. P1GF, however, only binds to
the extracellular domain of FLT with high affinity and does not
bind to the equivalent extracellular region of KDR. VEGF is able to
compete efficiently for PlGF binding to sFLT whereas PlGF competes
less efficiently for VEGF binding. These binding data demonstrate
that VEGF complexes with sFLT somewhat tighter than does PIGF.
Competitive binding infers that the VEGF and PlGF sites on sFLT are
probably either overlapping or identical. Thus, sFLT will inhibit
both PIGF and VEGF function.
EXAMPLE 4
[0078] Inhibition of VEGF binding by sVEGF-RI--The ability of
sVEGF-RI to inhibit VEGF binding to HUVECs was tested. HUVECs were
plated at 50,000 cells/well in 24 well plates precoated with
gelatin, and allowed to grow to confluence. A constant amount of
[.sup.125I]VEGF (100,000 cpm) was mixed with various amounts of
partially purified sVEGF-RI in binding buffer, in a total volume of
200 .mu.l and preincubated at room temperature for 1 hour. Samples
were added to the cells and incubated for 4 hours at 4.degree. C.
with shaking. The medium was then aspirated and the cells were
washed three times with binding buffer. The bound radioactivity was
solubilized with 50 mM TRIS-HC1, pH 8.0, 150 mM NaCl, 1% NP40, 1%
BSA and counted in a y counter.
[0079] The results are shown in FIG. 8. At the highest
concentration of sVEGF-RI, VEGF binding to HUVECs was reduced by
70%. It may, however, be difficult to completely inhibit binding to
the cellular membrane bound receptor since one molecule of sVEGF-R
bound to a VEGF dimer may be able to bind to cell associated
receptor to form an inactive (sVEGF-RI)-VEGF-(membrane spanning
VEGF receptor) complex.
EXAMPLE 5
[0080] Inhibition of VEGF mediated mitogenesis by sVEGF-RI
Mitogenic inhibition--Since sVEGF-RI was able to inhibit VEGF
binding to endothelial cells, it was then determined that the
soluble receptor could inhibit VEGF induced mitogenesis in HUVECs.
HUVECs were plated in gelatin coated 96 well plates at a density of
4000 cells/well in 100 ml of DME supplemented with 10% heat
inactivated fetal calf serum plus antibiotics (penicillin G, 100
units/ml; streptomycin sulfate, 100 mg/ml). After 16 hours the
medium was changed and test samples were added, cells were
preincubated with a variable amount of purified sVEGF-RI for 15
minutes at 37.degree. C. before growth factor (10 ng/ml) was added.
The cells were incubated for 24 hours then
[methyl-.sup.3H]thymidine (0.8 mCi/well; 20 Ci/mmol: 1 Ci=37 GBq,
final specific activity of 0.8 mCi/nmole) was added followed by
incubated for an additional 72 hours at 37.degree. C. under 5%
CO.sub.2. The cells were then washed twice with Hank's balanced
salt solution adjusted to pH 7.5 with 25 mM Hepes, 0.1% BSA. The
cells were then lysed, the DNA was solubilized with 0.2 M
Na.sub.2CO.sub.3, 0.1 M NaOH, and [.sup.3H]thymidine incorporation
was quantified by scintillation counting. The results are shown in
FIG. 9. sVEGF-RI was able to completely inhibit VEGF induced
[.sup.3H]thymidine incorporation in HUVECs.
EXAMPLE 6
[0081] Purification of baculovirus expressed sVEGF-RI from Sf9
cells--Culture medium from Sf9 cells infected with a baculovirus
construct designed to express sVEGF-RI (Example 2) was
chromatographed through a heparin Sepharose CL-6B (Pharmacia)
column (0.7.times.4 cm). The column was washed with 5 volumes of 10
mM Na-phosphate buffer, pH 6.2, 0.1 M NaC1, followed by 6 ml of 10
mM Na-phosphate buffer, pH 6.2, 0.6 M NaC1. The sVEGF-RI was eluted
with 10 mM Na-phosphate buffer, pH 6.2, 1.0 M NaC1. Polyacrylamide
gel electrophoresis was performed which demonstrated greater than
90% purity (as judged by coomassie blue staining) of the
recombinantly produced sVEGF-R (FIG. 5). The identity of the
protein was confirmed by N-terminal protein sequence analysis. The
actual N-terminus (Ser Lys Leu . . . ) of the recombinant protein
differs by two amino acids from that predicted by Shibuya et al.,
supra. (Ser-Ser-Ser . . . ). The peptidase cleavage site in
sVEGF-RI produced in Sf9 cells was between residues gly-26 and
ser-27.
EXAMPLE 7
[0082] Construction of KDR-related sVEGF-R--Soluble forms of KDR (a
known VEGF receptor) [Terman, B. I. et al., (1991) Oncogene 6, pp.
1677-1683; Terman, B. I. et al., (1992) Biochem. Biophys. Res.
Comm. 187, pp. 1579-1586] may exist naturally but have not yet been
identified. A soluble form of KDR is recombinantly constructed by
modifying its coding sequence by PCR using the primers 1) 5'
TTTGGATCCCTGCAGACAGATCTACGTTTGAGAACC 3' (SEQ. ID. NO.: 7) and 2) 5'
TTTTGGATCCTTAACGCTCTAGGACTGTGAGC 3' (SEQ. ID. NO.: 8), and pKDRA
(the Xhol/EcoRl fragment coding for the extracellular and
transmembrane domain of KDR cloned into the EcoRI site of pGEM 7Z
obtained from Promega) as a template (FIG. 17). This generated a
translation stop codon after amino acid residue number 663 of KDR
which corresponds to the extracellular domain of full length KDR.
This modified fragment is then used to replace the Pstl/BamHl
fragment of pKDRA generating a truncated form of the KDR gene (FIG.
10) which codes for a soluble receptor denoted sVEGF-RII (FIG. 11).
The Xhol site at base pair number 257 is then changed to a BamHl
site by standard cloning techniques. Another truncated form of the
KDR receptor is created with primer 1 shown above, and primer 3) 5'
TTTTGGATCCAACGGTCCCTAGGATGATGAC 3', (SEQ. ID. NO.: 9) (FIG. 12).
This form of KDR, denoted VEGF-RTMII, is truncated at the
C-terminal side of the transmembrane domain and therefore retains
the transmembrane region (FIG. 13). A similar form of the FLT
receptor is generated by PCR using the primers 4) 5'
AGCACCTTGGTTGTGGCTGACTC 3' (SEQ. ID. NO.: 10) and 5) 5'
TTTTGGATCCTTAGATAAGGAGGGTTAATAGG 3' (SEQ. ID. NO.: 11) and plasmid
pmFLT (full length flt cloned into the EcoRI site of pGEM3Z
obtained from Promega) as a template (FIG. 16). The 780 base pair
PCR fragment can then be cloned together with the EcoRl/Xbal
fragment from pmFLT to produce an EcoRl/BAMHl fragment (FIG. 14)
encoding a truncated form of FLT (denoted VEGF-RTMI) which retains
the transmembrane domain but lacks the cytoplasmic domain (FIG.
15). The EcoRl site at the 5' end of the gene is then modified to a
BamHl site. The resulting truncated forms of KDR and FLT are then
cloned into pBluebaclll (Stratagene) for expression in Sf9 insect
cells. Characterization of these constructed truncated forms of
VEGF receptors is accomplished by the techniques used to
characterize sVEGF-RI as in Examples 2, 3, 4, 5, and 6.
EXAMPLE 8
Identification and Partial Purification of a Soluble VEGF Binding
Protein
[0083] A mRNA encoding a soluble version of Flt was expressed in
HUVECs. The recombinant sFlt protein, when expressed in Sf9 insect
cells (BVsFlt), was found to bind tightly to heparin Sepharose. To
determine if sFlt protein was expressed by HUVECs, conditioned
medium from cultured HUVECs was filtered through a 0.22 .mu.m
membrane and passed over a heparin sepharose column. The heparin
column was eluted with a step gradient and fractions were tested
for binding to [.sup.125I] VEGF by covalent crosslinking. VEGF
binding activity eluted at similar NaCl concentrations as the
BVsFlt protein and was found in the 0.6-1.2 M NaCl step fraction.
An equal volume of EndoUV medium (endothelial cell growth medium)
not conditioned was chromatographed and had no VEGF binding
activity in the 0.6-1.2 M NaCl fraction. The VEGF binding activity
from HUVECs when crosslinked to labeled VEGF formed complexes which
migrate slower on SDS/PAGE than VEGF complexes formed with BVsFlt.
VEGF binding fractions were pooled and further separated by cation
exchange chromatography with a linear NaCl gradient. Again, VEGF
binding activity from the endothelial cell conditioned medium
elutes at a similar position as BVsFlt.
[0084] The chromatography data shows that the partially purified
HUVEC VEGF binding protein behaves similar to BVsFlt. To determine
if this VEGF binding protein is related to Flt, antibodies against
peptides based on the N-terminus and third immunoglobulin-like
domain in the extracellular region of Flt were prepared. Fractions
from the mono S column that produced high molecular weight
complexes when covalently crosslinked to [.sup.125I] VEGF were
analyzed by Western blot analysis. These data show that a 116 kDa
protein band which co-elutes with VEGF binding activity was
detected by both antibodies, thus the binding activity isolated
from human endothelial cells is a soluble form of Flt.
Sequence CWU 1
1
* * * * *