Methods for use of vascular endothelial growth factor antagonists
Inventors
Bottaro, Donald P. • Cecchi, Fabiola
Assignees
US Department of Health and Human Services
Publication Number
US-9550818-B2
Publication Date
2017-01-24
Expiration Date
2033-04-26
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Abstract
The present invention provides variant VEGF polypeptides which have been altered in their C-terminal heparin binding region to lower their heparin binding affinity. These variants have been found to act as receptor antagonists for VEGF receptors and antagonize angiogenesis. These variants are useful to treat diseases characterized by pathological angiogenesis.
Core Innovation
The invention provides variant vascular endothelial cell growth factor (VEGF) polypeptides altered in their C-terminal heparin binding region to lower their heparin binding affinity. These variants act as receptor antagonists for VEGF receptors and antagonize angiogenesis. They retain substantial affinity for VEGF receptors VEGFR-1 (FLT-1) and VEGFR-2 (KDR/FLK-1) while having reduced or repelled binding to heparin and heparan sulfate proteoglycans compared to native VEGF. This receptor antagonism leads to inhibition of pathological angiogenesis.
The problem addressed by the invention arises from the critical role of VEGF signaling in pathological angiogenesis associated with diseases such as cancer and ocular diseases. Existing VEGF antagonists, such as neutralizing antibodies and ATP binding site antagonists, have limitations including high production costs and off-target effects. There is a need for effective VEGF receptor antagonists that can be produced more cost-effectively and that can inhibit VEGF signaling even when receptor activation is independent of VEGF binding.
The invention discovered that introducing opposite charge substitutions at critical heparan sulfate (HS) binding residues in the VEGF heparin binding domain unexpectedly produces a competitive antagonist of VEGF signaling that inhibits angiogenesis. The mechanism involves receptor occupancy by the variant polypeptide combined with charge-based repulsion of heparan sulfate from the ligand/receptor complex, preventing receptor activation. This strategy provides a general and effective means of antagonizing VEGF and other HS-binding growth factors.
Claims Coverage
The patent contains multiple claims focusing on methods for treating diseases characterized by pathological angiogenesis using VEGF variant polypeptides with specific amino acid substitutions. The claims cover the variant's maintained receptor affinity, specific sequences, and the targeted diseases.
Use of VEGF variant polypeptides with acidic substitutions in heparin binding domain for treatment
Administering a pharmaceutically effective amount of a VEGF variant polypeptide that antagonizes VEGF-mediated angiogenesis and comprises polypeptides selected from SEQ ID NO:25, SEQ ID NO:26 with glutamic acid or aspartic acid substitutions at specified positions, or a polypeptide having at least 95% identity to these sequences with the identified substitutions.
Maintenance of receptor affinity in VEGF variants
The variant polypeptide maintains substantially the same affinity for VEGFR-1 (FLT-1) and VEGFR-2 (KDR/FLK-1) as the native VEGF, ensuring effective receptor binding despite altered heparin binding.
Use of specific variant sequences with R to E substitutions
The variant polypeptides include those comprising SEQ ID NO:6, SEQ ID NO:7, or polypeptides having at least 95% identity to these sequences and possessing the arginine to glutamic acid substitutions.
Specific inclusion of the VEGF variant comprising SEQ ID NO:7
Use of the variant polypeptide SEQ ID NO:7, which contains glutamic acid substitutions at the critical heparin binding residues, as an active agent in the described treatment method.
Treatment of diseases characterized by pathological angiogenesis including cancer and ocular diseases
The method is applied specifically to treating diseases characterized by pathological angiogenesis such as cancer (including metastatic cancer), macular degeneration, and diabetic retinopathy.
The independent claims describe methods of treating pathological angiogenesis by administering VEGF variants with specific acidic amino acid substitutions in the heparin binding domain, maintaining receptor affinity, and antagonizing VEGF activity. They highlight particular variant sequences and target diseases like cancer and ocular angiogenic disorders.
Stated Advantages
Variant VEGF polypeptides provide competitive receptor antagonism of VEGF signaling and angiogenesis.
Antagonists can be produced more cost-effectively than antibodies requiring mammalian expression systems.
The receptor antagonism strategy enables inhibition of receptor activation even when receptor activation is independent of VEGF binding.
Charge-based repulsion of heparan sulfate from the ligand/receptor complex offers a general and effective approach for developing signaling antagonists of HS binding growth factors.
Documented Applications
Treatment of diseases characterized by pathological angiogenesis, including cancer.
Treatment of ocular diseases involving pathological angiogenesis such as macular degeneration and diabetic retinopathy.
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