A short presentation on VEGFR and its inhibitors with a special focus on their interactions made with the receptor.

1. VEGFR AND ITS SMALL MOLECULE
INHIBITORS: IMPLICATIONS IN
GLIOBLASTOMA
Batch- M. Pharm 2013-15
Presented by Ms. Heena Bhojwani
Under the guidance of Dr. Urmila Joshi
At Prin. K. M. Kundnani College of Pharmacy

2. Presentation Overview
 What is Glioma?
 Types of Glioma
 Glioblastoma multiforme (GBM)
 Tumor Angiogenesis
 Angiogenic Switch - Judah Folkmans’ theory
 Process of Tumor Angiogenesis
 Activation of the VEGFR
 Signal Transduction through VEGFR
 Targets for treatment of Glioblastoma
 Vascular Endothelial Growth Factor Receptor (VEGFR)
 VEGFR-2 kinase domain
 Binding of ATP
 Small Molecule Inhibitors of VEGFR2
 Side effects of VEGFR2 Inhibitors
 Conclusions
 References 2 of 34

3. WHAT IS GLIOMA?
 Glioma is a common type of primary brain tumor.
 Originate in the glial cells in the brain.
 Arise from three different types of cells:
a. Astrocytes
b. Oligodendrocytes
c. Ependymal cells.
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4. Types of Glioma
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5. ASTROCYTOMAS and Glioblastomas
 Astrocytomas are developed from astrocytes.
 Often found in the cerebrum and cerebellum.
 High-grade astrocytomas are called Glioblastoma
multiforme.
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6. GLIOBLASTOMA MULTIFORME (GBM)
 Accounts for 17% of all primary central nervous
system tumors.
 Classified by the World Health Organization as a
grade IV malignancy.
 Commonly occur as:
I. de novo (also called primary GBMs)
II. Due to the progression of lower grade tumors to
higher malignancy (secondary GBMs).
6 of 34Flavia R.S. Lima , Suzana Assad Kahn, Rossana C. Soletti , Deborah Biasoli, Tercia, Alves Anna Carolina C. da Fonseca, Celina Garcia,
Luciana Romão, José Brito, Jane Faria, Helena Borges, Vivaldo Moura-Neto, Glioblastoma: Therapeutic challenges, what lies ahead,
Biochimica et Biophysica Acta 1826, 2012, 338–349.

7. ANGIOGENIC SWITCH:
JUDAH FOLKMAN’S THEORY
 Balance of naturally
occurring pro- and anti-
angiogenic signals is
disrupted.
 Process of new blood
vessel formation occurs.
 New blood vessel
formation induced by
hypoxia and number of
growth factors.
8 of 34James M. Hamby and H. D. Hollis Showalter,Small Molecule Inhibitors of Tumor-Promoted Angiogenesis,Including Protein Tyrosine Kinase Inhibitors
Pharmacol. Ther. Vol. 82, Nos. 2–3, pp,1999, 169–193.

8. Tumor Angiogenesis
 1971: Surgeon Judah Folkman hypothesizes that tumor growth is dependent
upon angiogenesis.
 A vital process in the progression of gliomas to glioblastoma.
 Responsible for the growth of small, localized neoplasm's into larger, growing,
and potentially metastatic tumors.
 Although glioblastoma rarely metastasizes, it almost always recurs locally due
to diffuse infiltration resulting from angiogenesis.
 Regulated by growth factors that bind to their specific receptors on endothelial
cells.
 Growth factors induce the proliferation and migration of endothelial cells.
7 of 34James M. Hamby and H. D. Hollis Showalter,Small Molecule Inhibitors of Tumor-Promoted Angiogenesis,Including Protein Tyrosine Kinase
Inhibitors, Pharmacol. Ther. Vol. 82, Nos. 2–3, pp,1999, 169–193.

9. PROCESS OF TUMOR ANGIOGENESIS
VEGF
VEGFR
INCREASED
VASCULAR
PERMEABILTY DISSOCIATION
OF
PERICYTE
COVERAGE
Requires
cathepsin B,
MMP,
Other matrix
Proteins
Hypoxia
Induces pro-
angiogenic
factor
production
HIF
PERICYTES
ASSOCIATION
9of 34
Michael L.H.Wong, Amy Prawira, Andrew H.Kaye, Christopher M. Hovens, Tumor Angiogenesis: Its mechanism and therapeutic implications in malignant gliomas, Journal

10. ACTIVATION OF VEGFR
Covalently
linked
Binding of
VEGF
Autophosphorylatio
n of Tyr residues
Receptor
Dimerization
ATP
ADP
ATP
ADP
ACTIVATED
RECEPTOR
10 of 34Edward Stuttfeld and Kurt Ballmer-Hofer, Structure and Function of VEGF Receptors, IUBMB Life, 61(9), 2009, 915–922.

11. Signal Transduction Through VEGFR
Raf
MEK
ERK
CELL PROLIFERATION
P38
MAPK
HSP27
CELL MIGRATION
VASCULAR
PERMEABILITY
Shb
PI3K
PKB
eNOS
CELL SURVIVAL
11 of 34Sonia Tugues, Sina Koch, Laura Gualandi and Xiujuan Li, Vascular Endothelial Growth Factors and Receptors: Anti-angiogenic Therapy in treatment of cancer,
Molecular Aspects of Medicine, 32, 2011, 88-111.

12. Targets for treatment of Glioblastoma
Wortmannin
HIF-1 α
Translation
inhibitor
Semaxinib
VEGFR-2
Inhibitor
Celecoxib
Cox-2
inhibitor
Cilengitide
αvβ3 inhibitor
Marimastat
MMP Inhibitor
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13. VASCULAR ENDOTHELIAL GROWTH FACTOR
RECEPTOR (VEGFR)
VEGFR-1 VEGFR-2 VEGFR-3
NRP-1
LYMPHANOGENESIS
VASCULOGENESIS AND ANGIOGENESIS
NRP-2
VEGF-B
VEGF-A VEGF-E VEGF-C
VEGF-D
KINASE DOMAINS OF VEGFR 1 AND 2 ARE CONSERVED ONES, WITH 70%
HOMOLOGY BUT CARBOXY TERMINAL IS DIFFERENTIATED. 13 of 34

14. Organization of the VEGF receptor protein–tyrosine kinases. Numbers on the right of each
receptor correspond to human tyrosine residue phosphorylation sites.
14 of 34
Robert Roskoski Jr., Vascular endothelial growth factor (VEGF) signaling in tumor progression, Critical Reviews in Oncology/Hematology 62 , 2007, 179–213.

15. VEGFR-2 KINASE DOMAIN
Crystal Structure of the protein kinase catalytic core of VEGFR2
15 of 34
Robert Roskoski Jr., Vascular endothelial growth factor (VEGF) signaling in tumor progression, Critical Reviews in Oncology/Hematology 62 , 2007, 179–213.

16. STRUCTURAL BINDING OF ATP:
ATP binding with N-H of
Cys919 and C=O of Glu917
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17. Diagram of the inferred interactions between the human VEGF receptor 2 protein–tyrosine kinase catalytic core residues, ATP, and a
protein substrate.
•Asp1028: orients the
tyrosyl group of the
substrate protein in a
catalytically competent
state.
•Asp1046 : binds to Mg2+
that in turn coordinates
the β and γ phosphate
groups of ATP; Asp1046
also binds to the α-
phosphate.
•In the activated enzyme ,
Lys868 is an forms ion pairs
with the α and β phosphates
of ATP and with Glu885 of
the α C helix.
•In the inactive enzyme
which lacks bound ATP,
Lys868 binds instead to an
activation segment
phosphotyrosine and is far
from Glu885.
17 of 34
Robert Roskoski Jr., Vascular endothelial growth factor (VEGF) signaling in tumor progression, Critical Reviews in Oncology/Hematology 62 , 2007, 179–213.

18. VEGFR-2 AS TARGETS:
INHIBITION OF TUMOR ANGIOGENESIS
 Phosphorylation of the tyrosine residues is essential for the
activation of receptor.
 Thus ATP binding in the catalytic core.
 Inhibition can be achieved by selectively targeting the enzymatic
activity of kinases with small ATP competitive molecules that can
occupy the catalytic ATP binding site.
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19. STRUCTURAL FEATURES OF INHIBITORS
 A common structural feature of the inhibitors is a planar
heterocyclic ring system
I. For binding to the Adenine pocket
II. To mimic the adenine –kinase interaction by making
backbone hydrogen bond interactions
 Can posses substituted anilino group:
I. In some class of drugs be can a contributing factor for
selectivity.
II. Bind to the hydrophobic pocket.
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20. Crystal structure showing the Cys919 residue of hinge region, Adenine site, Glu885 of α
C helix and Asp 1046 of DFG motif with Compound X bound to them.
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21. SMALL MOLECULE INHIBITORS OF VEGFR-2
VEGFR-2 INHIBITORS
Indolin-2-ones
Indolocarbazole
Anilinoquinazolines
Anilinophthalazines
Disubstituted Urea
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22. Classification on the basis of
action
Drugs acting as
only VEGFR-2
inhibitors
Examples:
Sunitinib, Vatalanib,
Vandetnib etc.
Drugs acting as
VEGFR-2 and Raf
inhibitors
Example:
Sorafenib
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23. 1.INDOLIN-2-ONES (OXINDOLES) -SUNITINIB
X Ray crystal structure of VEGFR-2 in
complex with Sunitinib
23 of 34
T.L. Underiner, B. Ruggeri and D.E. Gingrich, Development of Vascular Endothelial Growth Factor Receptor (VEGFR) Kinase Inhibitors as Anti-
Angiogenic Agents in Cancer Therapy, Current Medicinal Chemistry, 11, 2004, 731-745.

24. -NH GROUP:
H-BOND
DONOR
CARBONYL
GROUP:
H-BOND
ACCEPTOR
SUNITINIB
DIRECT BINDING OF SUNITINIB TO THE ATP-BINDING SITE OF VEGFR-2
3of34
Julio Caballero, Camila Muñoz, Jans H. Alzate-Morales, Susana Cunha, Lurdes Gano, Ralf Bergmann , Joerg Steinbach, Torsten Kniess, Synthesis, in silico, in vitro,
and in vivo investigation of 5-[11C]methoxy-substituted sunitinib, a tyrosine kinase inhibitor of VEGFR-2, European Journal of Medicinal Chemistry, 58, 2012, 272-

25. 2. INDOLOCARBAZOLE-SATUROSPORINE
 Binds similar to sunitinib
i.e via H-donor/acceptor
interaction.
lactam ring responsible for binding
25 of 34
T.L. Underiner, B. Ruggeri and D.E. Gingrich, Development of Vascular Endothelial Growth Factor Receptor (VEGFR) Kinase Inhibitors as Anti-
Angiogenic Agents in Cancer Therapy, Current Medicinal Chemistry, 11, 2004, 731-745.

26. 3. ANILINOQUINAZOLINES - VANDETANIB
Quinazoline - resides deep inside
Adenine pocket
Accepts H-bond from
Cys-912
Fills hydrophobic pocket
26 of 34
T.L. Underiner, B. Ruggeri and D.E. Gingrich, Development of Vascular Endothelial Growth Factor Receptor (VEGFR) Kinase Inhibitors as Anti-
Angiogenic Agents in Cancer Therapy, Current Medicinal Chemistry, 11, 2004, 731-745.

27. 4. ANILINOPHTHALAZINES -VATALANIB
Binds to Hydrophobic pocket
No direct H-bonding with hinge region
Makes hydrophobic
contacts with other
amino acids
Forms water
mediated H-
bonds with
hinge region
27 of 34T.L. Underiner, B. Ruggeri and D.E. Gingrich, Development of Vascular Endothelial Growth Factor Receptor (VEGFR) Kinase Inhibitors as Anti-
Angiogenic Agents in Cancer Therapy, Current Medicinal Chemistry, 11, 2004, 731-745.

28. 5. DISUBSTITUTED UREA - SORAFENIB
X Ray crystal structure of sorafenib
in complex with kinase domain of
VEGFR-2
28 of 34T.L. Underiner, B. Ruggeri and D.E. Gingrich, Development of Vascular Endothelial Growth Factor Receptor (VEGFR) Kinase Inhibitors as Anti-
Angiogenic Agents in Cancer Therapy, Current Medicinal Chemistry, 11, 2004, 731-745.

29. SORAFENIB
H-Bond
Acceptor
H-Bond
Dnor
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30. SIDE EFFECTS OF VEGFR-2 INHIBITORS
 Hypertension
 Bleeding
 Gastrointestinal upset
 Mucositis
 Skin toxicity
 Fatigue
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31. CURRENT VEGFR2 INHIBITORS
 Sorafenib (under clinical trials)- for reccurent
GBM
 Vatalanib in combination with other drugs
(under clinical trials)- for reccurent GBM
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32. CONCLUSION
 GBM is one of the most angiogenic tumors in humans,
thus anti-angiogenic drugs could be the ideal
molecules for the inhibition of this process.
 VEGFR2 is highly expressed in case of tumor
angiogenesis than VEGFR1. So VEGFR2 small
molecule inhibitors can be beneficial in management of
GBM along with other drugs.
32 of 34

33. 33 of 34

34. REFERENCES
 Robert Roskoski Jr., Vascular endothelial growth factor (VEGF) signaling in tumor progression, Critical Reviews
in Oncology/Hematology 62 , 2007, 179–213.
 James M. Hamby and H. D. Hollis Showalter,Small Molecule Inhibitors of Tumor-Promoted
Angiogenesis,Including Protein Tyrosine Kinase Inhibitors, Pharmacol. Ther. Vol. 82, Nos. 2–3, pp,1999, 169–193.
 Edward Stuttfeld and Kurt Ballmer-Hofer, Structure and Function of VEGF Receptors, IUBMB Life, 61(9), 2009, 915–922.
 Michael L.H.Wong, Amy Prawira, Andrew H.Kaye, Christopher M. Hovens, Tumor Angiogenesis: Its mechanism
And therapeutic implications in malignant gliomas, Journal of Clinical Neuroscience, 16, 2009, 1119-1130.
 Sonia Tugues, Sina Koch, Laura Gualandi and Xiujuan Li, Vascular Endothelial Growth Factors and Receptors:
Anti-angiogenic Therapy in treatment of cancer, Molecular Aspects of Medicine, 32, 2011, 88-111.
 S. Schenone,1, F. Bondavalli1 and M. Botta2, Antiangiogenic Agents: an Update on Small Molecule VEGFR
Inhibitors, Current Medicinal Chemistry, 14, 2007, 2495-2516.
 T.L. Underiner, B. Ruggeri and D.E. Gingrich, Development of Vascular Endothelial Growth Factor Receptor
(VEGFR) Kinase Inhibitors as Anti-Angiogenic Agents in Cancer Therapy, Current Medicinal Chemistry, 11, 2004,
731-745.
 Xiaoping Jiang, Guangchuan Ou, Depeng Yan, Min Zhang and Xianyou Yuan, 3D-QSAR Studies of VEGFR-2
Kinase Inhibitors Based on Docking, Letters in Drug Design & Discovery, 8, 2011, 926-942.
 Stephen J. Boyer, Small Molecule Inhibitors of KDR (VEGFR-2) Kinase: An Overview of Structure Activity
Relationships, Current Topics in Medicinal Chemistry 2, 2002, 973-1000.
 Zachary A. Knight and Kevan M. Shokat, Features of Selective Kinase Inhibitors , Chemistry & Biology, Vol. 12,
2005, 621–63.
 Julio Caballero, Camila Muñoz, Jans H. Alzate-Morales, Susana Cunha, Lurdes Gano, Ralf Bergmann , Joerg
Steinbach, Torsten Kniess, Synthesis, in silico, in vitro, and in vivo investigation of 5-[11C]methoxy-substituted
sunitinib, a tyrosine kinase inhibitor of VEGFR-2, European Journal of Medicinal Chemistry, 58, 2012, 272-280.
 Flavia R.S. Lima , Suzana Assad Kahn, Rossana C. Soletti , Deborah Biasoli, Tercia, Alves Anna Carolina C. da
Fonseca, Celina Garcia, Luciana Romão, José Brito, Jane Faria,
Helena Borges, Vivaldo Moura-Neto, Glioblastoma: Therapeutic challenges, what lies ahead, Biochimica et Biophysica Acta
1826, 2012, 338–349.
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