angiogenisis in tumer (cancer)

2. by
‫عون‬ ‫عبد‬ ‫سارة‬
‫نوري‬ ‫فاضل‬ ‫سجاد‬
‫موشنة‬ ‫سالم‬ ‫حسين‬
‫اياد‬ ‫ندى‬
‫خميس‬ ‫حسن‬

3. formation of new blood vessels
There are two ways to form the blood vessels in the body ?
1-Vasculogenesis
2-Angiogenesis
Vasculogenesis is the generation of blood vessels from endothelial cell progenitors
(angioblasts). It is responsible for the formation of the primary vasculature of the body
during early embryonic development development of the cardiovascular system. this is
followed by formation of a vascular tree and finally the cardiovascular system.
after which angiogenesis is
responsible for most, if not
all, blood vessel growth
during development and
in disease like cardiovascular disease

4. What is Angiogenesis ?
angiogenesis is the formation of new blood vessels from pre-existing vessels
and is a normal process in growth and development, as well as in wound healing.
oangiogenesis is defined as the growth of blood vessels and is an
important natural process used by the body for reproduction and for
healing injured tissues
oblood vessels bring oxygen and nutrients via the circulation to nourish all
tissues in the body
othe cells comprising blood vessels are called endothelial cells
othe endothelial cells of a blood vessel also produce molecules that
support the growth of tissues
ocancer cells take over the body's control of angiogenesis in order to
recruit their own private blood supply And the angiogenesis have
important role in the tumor to give nutrient an oxygen for growth the
tumor and for proliferation and important in metastasis the tumor

6. Intussusceptive
angiogenesis
Sprouting
angiogenesis
TYPE

7. Sprouting angiogenesis
Sprouting angiogenesis is the basic mechanism seen in the growth of new blood
vessels. It was the first identified form of angiogenesis. It occurs in several well-
characterized stages.
There are sequential steps that are finely regulated by chemical mediators in the body.
Significant role is played by factors such as VEGF
First, biological signals known as angiogenic growth
factors VEGF and FGF-Β produced by fibroblasts,
macrophages, endothelial cells and keratinocytes
are principal factors which regulate angiogenesis
activate receptors present on endothelial cells

8. Sprouting angiogenesis
Second step : activated endothelial cells begin to release enzymes like proteases
Matrix metalloprotease
Plasminogen activator …that activate plasminogen into plasmid ;which degrades
several components of ECM
. These proteases can break down proteins and cells of the basement membrane. This
creates opening in the existing blood vessel that allows the escape of the activated
endothelial cells from the existing orginal blood vessel.

9. The endothelial cells then proliferate
into the surrounding matrix and form
solid sprouts connecting neighboring
vessels. As sprouts extend toward the
source of the angiogenic stimulus, new
endothelial cells using adhesion
molecules, called integrins that help
them bind to each other to form chains.
These sprouts then form loops to
become tubular blood vessels. Sprouting
occurs at a rate of several millimeters
per day, and enables new vessels to
grow across gaps in the vasculature. It
is markedly different from splitting
angiogenesis, however, because it forms
entirely new vessels as opposed to
splitting existing vessels.

10. Sprouting angiogenesis
FINAL STEP
Maturation of neovasculature
When sufficient neovascularization has occurred the angiogenic factors are down
regulated
Balance equilibrium

12. Intussusceptive Angiogenesis
Intussusception, also known as splitting angiogenesis, was first observed in
neonatal rats. In this type of vessel formation, the capillary wall extends into
the lumen to split a single vessel in two. There are four phases of
intussusceptive angiogenesis.
First, the two opposing capillary walls establish a zone of contact.
Second, the endothelial cell junctions are reorganized and the vessel bilayer
is perforated to allow growth factors and cells to penetrate into the lumen.
Third, a core is formed between the two new vessels at the zone of contact
that is filled with pericytes and myofibroblasts. These cells begin laying
collagen fibers into the core to provide an extracellular matrix for growth of
the vessel lumen.
Finally, the core is fleshed out with no alterations to the basic structure.

13. Intussusceptive Angiogenesis
Intussusception is important because it is a reorganization of existing cells. It
allows a vast increase in the number of capillaries without a corresponding
increase in the number of endothelial cells. This is especially important in
embryonic development as there are not enough resources to create a rich
microvasculature with new cells every time a new vessel develops.

15. Angiogenesis in cancer
During tumor growth, angiogenesis is required for proper nourishment and removal of metabolic
wastes from tumor sites .In physiologic conditions, cells are located within 100 and 200 micro
meter. from blood vessels, their source of oxygen. When a multicellular organism is growing, cells
induce angiogenesis and vasculogenesis in order to recruit new
blood supply. In a pathological condition such as cancer, angiogenesis is required for tumor
survival and proliferation. The microenvironment of solid human
tumors is characterized by heterogeneity in oxygenation

16. Effect of hypoxia on tumer and angiogenisis
Hypoxia in tumors is primarily a pathophysiologic consequence of structurally and functionally
disturbed microcirculation and the deterioration of diffusion conditions
Tumor hypoxia appears to be strongly associated with tumor propagation, malignant progression,
and resistance to therapy, and it has thus become a central issue in tumor physiology and cancer
treatment
Hypoxia arises early in the process of tumor development because rapidly proliferating tumor cells
outgrow the capacity of the host vasculature
Tumor cells located more than 100 micro m away from blood vessels become hypoxic
Some clones will survive by activating an angiogenic pathway. If new blood vessels do not form, tumor clones
will be confined within 1–1.5 mm diameter
Such clones remain dormant from months to years before they switch to an angiogenic phenotype
Vascular cooption is confined only in the tumor periphery and gradual tumor expansion causes a
progressive central hypoxia. Hypoxia induces the expression of proangiogenic factors through hypoxia-
inducible factor-a, and if proangiogenic factors are in
excess of antiangiogenic factors, it may lead to the switch to an angiogenic phenotype

17. Carmeliet and Jain. Nature.
2000= Proangiogenic factor, eg. VEGF
= Angiogenic inhibitor
Angiogenesis
Mutation
Hypoxia
HIF-1
VEGF
dormant
Secretion of angiogenic factors Rapid
growth of
cancer
Regression of cancer

18. THE ANGIOGENIC SWITCH
The transition from a pre-vascular to a vascularized tumor phenotype is called
the angiogenic switch. This switch is controlled by a balance between pro- and
anti-angiogenic factors, which are secreted by the tumor cells themselves or by
cells of the tumor microenvironment (inparticular stromal cells and immune
cells). The most prominent pro-angiogenic factors arevascular endothelial
growth factor (VEGF) and fibroblast growth factor (FGF). Conversely, proteolytic
fragments of the extracellular matrix (ECM) can act as potent angiogenesis
inhibitors
(e.g., endostatin). Other anti-angiogenic factors include cleaved derivatives of plasminogen
(angiostatin) or antithrombin III (C-terminal antithrombin-fragment). The expression of pro and
anti-angiogenic factors by cancer cells is controlled directly by oncogenes, tumor suppressor
genes and transcription factors, but also indirectly by environmental factors (such as oxygen
or glucose supply)..
Genetic and epigenetic changes can modulate the response of the endothelial cells to
VEGFand FGF and thus influence the angiogenic balance.
. In patients, the angiogenic switch has been shown to occur in a number of cancer types,
most prominently in breast and cervical cancer

20. Structure of tumor vasculature
In tumors, the normal configuration of blood vessels isspreading without any organization, following tortuous
paths andchanging in diameter without any organization. Largecaliber tumor vessels may have thin walls usually
belonging to capillaries or an incomplete basement membrane and an unusual pericyte coat
Pericytes of normal capillaries have skeletal shapes and are closely attached to endothelial cells. In contrast,
pericytes in a tumor model show irregular shapes and are loosely attached to endothelial cells. Many projections
are observed from the pericyte into the interstitial space. Arrow:
pericytes of normal capillary. Arrowhead: pericytes of tumor capillary.

21. An imbalance in angiogenic factors, like vascular endothelial growth factor (VEGF) and angiopoietins, is
the main cause of this chaotic structure in a tumor vessels from which new vessels originate are
characterized by degradation of the basement membrane and decreased number of perycites and Tumor
vessels are hyperpermeable, mostly described as ‘leaky’, because of loss of adherence between endothelial
junctions as well as a discontinuous basement membrane. Vascular permeability allows the extravasation
of plasma proteins that constitute a momentary scaffold for migrating endothelial cells.
Another very common feature in tumor blood vessels is the presence of focal hemorrhages that occur
spontaneously mainly if the tumor cells express VEGF121 or VEGF165 The structural aberrations described so far in
tumor vessels are also coupled to molecular and functional disorders such as the overexpression of growth factors,
integrins, and the uptake of cationic liposomes

22. ENDOGENOUS ANGIOGENIC FACTORS
More than a dozen different proteins have been identified as angiogenic activators, including
• Vascular endothelial growth factor (VEGF)
• Basic fibroblast growth factor (bFGF)
• Angiogenin , transforming growth factor (TGF)-α, TGF-β
• Tumor necrosis factor (TNF)-α
• Platelet-derived endothelial growth factor
• Granulocyte colony-stimulating factor
• Placental growth factor
• Interleukin-8
• Hepatocyte growth factor
• Epidermal growth factor

23. SOURCE OF ANGIOGENIC FACTORS
• Angiogenic activity arises from the tumor cells itself in the form of
the release of angiogenic molecules such as basic fibroblast
growth factor;
• angiogenic activity arises from host cells recruited by the tumor
(ex. Macrophages), or is mobilized from the extracellular matrix, or
requires concomitant loss of physiological inhibition of endothelial
cell proliferation.

26. ENDOGENOUS ANGIOGENIC FACTORS
• VEGF is a powerful angiogenic agent in neoplastic tissues, as well as in normal
tissues. Under the influence of certain cytokines and other growth factors
• Some angiogenic phenotypes can be triggered by hypoxia resulting from the
increasing distance between the growing tumor cells and the capillaries or from the
inefficiency of new vessels. Hypoxia induces the expression of VEGF and its receptor
via hypoxia-inducible factor-1α (HIF-1α).
• Tumor cells feed on the new blood vessels by producing VEGF and then secreting it
into the surrounding tissue. When the tumor cells encounter endothelial cells, they
bind to receptors on the outer surface of the endothelial cell.

27. ENDOGENOUS ANGIOGENIC FACTORS
• The binding of VEGF to its receptor activates relay proteins that transmit a signal into the nucleus of
the endothelial cell.
• The nuclear signal prompts a group of genes to make products needed for new endothelial cell
growth.
• Endothelial cells activated by VEGF produce matrix metalloproteinases (MMPs).
• The MMPs break down the extracellular matrix which fills the spaces between cells and is made of
protein and polysaccharides.
• This matrix permits the migration of endothelial cells. The endothelial cells begin to divide as they
migrate into the surrounding tissues. Soon they organize into hollow tubes that evolve gradually into
a mature network of blood vessels with the help of an adhesion factor, such as integrin α or β.
• Newly formed blood vessels need to stabilize or mature. Angiotensin-1, -2, and their receptor Tie-2
can stabilize and govern vascular growth.

28. The binding of
VEGF to its
receptor
activates
relay
proteins
VEGF produce matrix
metalloproteinases
(MMPs).
MMPs break down
the extracellular
matrix
migration of
endothelial
cells
dividing of endothelial
cell
stabilize or mature by
Angiotensin-1, -2
ENDOGENOUS ANGIOGENIC FACTORS

29. VEGF Family
• VEGFA
• VEGFB
• VEGFC
• VEGFD
• VEGFE

30. ENDOGENOUS ANGIOGENIC FACTORS
• Among the VEGF family, VEGF-A, VEGF-B, VEGFC and VEGF-E acting on their
respective receptors cause proliferation of blood vessels, while VEGF-C and VEGFD
are involved in lymphangiogenesis.
• Vascular endothelial growth factor-A is also known as VEGF/vascular permeability
factor (VPF). Vascular endothelial growth factor-A is a heparin binding glycoprotein
that occurs in at least six molecular isoforms, which consist of 121, 145, 165, 183,
189, and 206 amino acids and are the result of alternative splicing of the mRNA.
• VEGF-A is a potent and very specific mitogen for vascular endothelial cells and
stimulates the full cascade of events required for angiogenesis, and is overexpressed
in a variety of tumors.

31. ENDOGENOUS ANGIOGENIC FACTORS
• VEGF-B exists as two protein isoforms, VEGF-B167 and VEGF-B186, resulting
from different spliced mRNA and binds specifically to VEGFR-1. However,
VEGF-B forms a heterodimer with VEGF-A, which may alter its interaction with
its biological receptors and modify its normal physiological effects. While
VEGF-B is widely expressed in heart, skeletal muscle, and vascular cells, its
biological function remains unclear. It has also been reported that VEGF-B
levels increase both throughout development and after birth, closely
correlating with the progression of cardiac angiogenesis.

32. ENDOGENOUS ANGIOGENIC FACTORS
• VEGF-C has a mature form that consists of a VEGF homology domain, Unlike VEGF-A, the
expression of VEGF-C does not appear to be regulated by hypoxia.
• The expression of VEGF-C appears to be restricted to early development and certain
pathological settings such as tumor angiogenesis and lymphangiogenesis.
• VEGF-D is known as induced growth factor (FIGF), these growth factors bind to the same
receptors on human endothelial cells, namely VEGFR-2 and -3. VEGF-C and VEGF-D bind
and activate VEGFR-3, regulating lymphangiogenesis as well as angiogenesis in the mid-
stages of embryogenesis.
• VEGF-E the interaction of VEGF-E with its receptor seems to promote endothelial cell
growth There is a significant overlap between the binding pocket of VEGF-A and VEGF-E on
VEGFR-2 which may suggest alliance of the two molecules in final response or alternatively
an antagonistic relationship between these two factors.

35. THE FIBROBLAST GROWTH FACTOR (FGF)
• The fibroblast growth factor (FGF) family with its prototype members FGF-1 (acidic FGF) and
FGF-2 (basic FGF) consists to date of at least 22 known members.
• FGF-1 stimulates the proliferation and differentiation of all cell types necessary for building
an arterial vessel, including endothelial cells and smooth muscle cells; this fact distinguishes
FGF-1 from other pro-angiogenic growth factors, such as vascular endothelial growth factor
(VEGF), which primarily drives the formation of new capillaries.
• One of the most important functions of fibroblast growth factor-2 (FGF-2 or bFGF) is the
promotion of endothelial cell proliferation and the physical organization of endothelial cells
into tube-like structures, thus promoting angiogenesis. FGF-2 is a more potent angiogenic
factor than VEGF or PDGF (platelet-derived growth factor); however, it is less potent than
FGF-1.

36. Balance of angiogenesis in cancer
Angiogenesis is stimulated when tumor tissues require nutrients and
oxygen. Angiogenesis is regulated by both activator and inhibitor
molecules. However, up-regulation of the activity of angiogenic factors is
itself not sufficient for angiogenesis of the neoplasm. Negative regulators
or inhibitors of vessel growth need to also be down-regulated

37. An angiogenesis inhibitor
An angiogenesis inhibitor is a substance that inhibits the
growth of new blood vessels (angiogenesis). Some
angiogenesis inhibitors are endogenous and a normal part
of the body's control, angiogenesis inhibitors are often
derived from circulating extracellular matrix proteins, and
others are obtained exogenously through pharmaceutical
drugs or diet

38. VEGF pathway inhibition
Inhibiting angiogenesis requires--- treatment with anti-angiogenic factors, or
drugs
Which reduce the production of pro-angiogenic factors, prevent them binding to
their receptors or block their actions
Inhibition of the VEGF pathway has become the focus of angiogenesis research as
approximately 60% of malignant tumors express high concentrations of VEGF

39. Inhibitors of angiogenesis
 . There are many naturally occurring proteins that can inhibit angiogenesis, including
 angiostatin,
 Endostatin
 Tumstatin
 Interferon
 Platelet factor 4
 Thorombospondin
 prolactin 16 kd fragment
 Tissue inhibitor of metalloproteinase-1, -2, and -3

40. Inhibitors of angiogenesis
 Angiostatin is composed of one or more fragments of plasminogen. It
induces apoptosis in endothelial cells and tumor cells, and inhibits migration and the
formation of tubules in endothelial cells. Immunohistochemical examination of
angiostatin-treated tumors indicated a decrease in the expression of mRNA for VEGF
and bFGF.
Endostatin is a naturally-occurring fragment derived from type XVIII
collagen. It is reported to serve as an anti-angiogenic agent, similar to angiostatin and
thrombospondin. Endostatin inhibits the growth factor
 Endostatin is a broad-spectrum angiogenesis inhibitor and may interfere with
the pro-angiogenic action of growth factors such as basic fibroblast growth factor
(bFGF/FGF-2) and vascular endothelial growth factor (VEGF)

41. Tumstatinis a protein fragment cleaved from collagen that serves as both an
antiangiogenic and proapoptotic agent.[1]

tumstatin has been shown to reduce angiogenesis in tumors, there is great
potential to use this knowledge as treatment for cancer. Tumstatin binds to the
endothelium of the tumor and is thus able to affect tumor growth.[9] By affecting
the apoptotic pathway, tumstatin inhibits the proliferation of endothelial cells.[6][1] It
has been shown that the efficacy of tumstatin in reducing angiogenesis in tumors
increases with tumor size.

One study showed that mice with a genetic αvβ3 integrin showed accelerated
tumor growth (integrins consisting of two noncovalently bound transmembrane α
and β subunits, are an important molecular family involved in tumor angiogenesis.
Integrin αvβ3 is highly expressed on activated endothelial cells, new-born vessels
as well as some tumor cells, but is not present in resting endothelial cells and most
normal organ systems, making it a suitable target for anti-angiogenic therapy.)
When tumstatin was replaced into the system, the tumor growth was disrupted and
the tumor shrunk.[11]

42. Prolactin 16-kD Fragment
A 16 kD N-terminal fragment of prolactin formed
endogenously by cleavage of intact prolactin. Possessing anti-
angiogenic properties, prolactin 16-kD fragment inhibits the
pro-angiogenic effects of basal fibroblast growth factor
(bFGF) and vascular endothelial growth factor (VEGF) on
endothelial cell proliferation, migration, and capillary
organization

45. Vascular Disrupting Agents in Cancer
Therapy
Vascular disrupting agents (VDAs) are distinguished
from anti-angiogenic agents by their ability to cause
a catastrophic vascular collapse in tumour tissue
within minutes to hours of drug administration,
leading to extensive tumour cell necrosis.
. Tumors cannot grow larger than 2mm without angiogenesis

46. Flavonoids
 DMXAA (5,6-dimethylxanthenone-4-acetic acid; and FAA (fl
avone acetic acid) are members of a series of drugs,
structurally distinct from the combretastatins, whose primary
site of action is unknown but which have multiple antivascular
actions including the induction of cytokines. Initial work found
that FAA induced extensive haemorrhagic necrosis and
reduced blood fl ow in animal tumour models, leading to the
development of derivatives, one of which, DMXAA, is 16 times
more potent than FAA and active in human tumours (Baguley
2003).

47. Other Biological VDAs
Various peptides, antibodies, antibody fragments or
growth factors are being designed to selectively bind
to tumour blood vessels and induce coagulation
and/or endothelial cell death. As for the low-
molecular-weight VDAs, these compounds are
designed to induce rapid tumour vascular shut-
down, leading to extensive tumour cell necrosis.

48. Antiangiogenic treatment of cancer
Inhibitors Mechanism
bevacizumab (Avastin) VEGF
carboxyamidotriazole inhibit cell proliferation and cell migration of endothelial cells
IL-12 stimulate angiogenesis inhibitor formation
thrombospondin inhibits binding of angiogenesis stimulators
inhibit basement membrane degradation
matrix metalloproteinase inhibitors
angiostatin
inhibit cell proliferation and induce apoptosis of endothelial

49. Antiangiogenic treatment of cancer
Inhibitors Mechanism
endostatin
inhibit cell migration, cell proliferation and survival of
endothelial cells
thalidomide inhibit cell proliferation of endothelial cells
thrombospondin
inhibit cell migration, cell proliferation, cell adhesion and
survival of endothelial cells
prolactin VEGF

50. anti-angiogenesis factors
 One of the most recent methods that is being developed for the delivery of anti-
angiogenesis factors to tumour regions in cancer sufferers is using genetically
modified bacteria that are able to colonize solid tumors in vivo. This method involves
genetically engineering bacterial species such
as Clostridium, Bifidobacteria and Salmonella by adding the genes for anti-
angiogenic factors such as endostatin or IP10 chemokine and removing any harmful
virulence genes. A target can also be added to the outside of the bacteria so that
they are sent to the correct organ in the body. The bacteria can then be injected into
the patient and they will locate themselves to the tumor site, where they release a
continual supply of the desired drugs in the vicinity of a growing cancer mass,
preventing it form being able to gain access to oxygen and ultimately starving the
cancer cells] .This method has been shown to work both in vitro and in vivo in mice
models, with very promising results.[. It is expected that this method will become
commonplace for treatment of various cancer types in humans in the future

51. Side effects of angiogenesis inhibitors
 Angiogenesis is important to many of the body’s normal processes.
Therefore, these drugs can cause a wide range of side effects, including:
1. High blood pressure
2. A rash and/or dry, itchy skin
3. Hand-foot syndrome, which causes tender, thickened areas on the skin,
sometimes with blisters, on palms and soles
4. Diarrhea
5. Fatigue
6. Low blood counts
7. Problems with wound healing or cuts re-opening

52. Diet
Some common components of human diets also act as mild
angiogenesis inhibitors and have therefore been proposed
for angioprevention, the prevention of metastasis through the
inhibition of angiogenesis. In particular, the following foods
contain significant inhibitors and have been suggested as part
of a healthy diet for this and other benefits:

53. Soy products such as tofu and tempeh,
(which contain the inhibitor "genistein")
Agaricus subrufescens mushrooms (contain the
inhibitors sodium
pyroglutamate and ergosterol)
Reishi mushrooms (via inhibition
of VEGF and TGF-beta)
Black raspberry (Rubus occidentalis) extract

54. Maitake mushrooms (via inhibition
of VEGF)
Phellinus linteus mushrooms(via active
substance Interfungins A inhibition
of glycation).
Green tea (catechins)Liquorice (glycyrrhizic acid)

55. References
 Robbins Basic Pathology, 9E by Vinay Kumar MBBS MD FRCPath (Author), Abul K. Abbas
MBBS (Author), Jon C. Aster MD PhD
 Tumor Angiogenesis Basic Mechanisms and Cancer Therapy
 https://en.wikipedia.org/wiki/Vascular_endothelial_growth_factor
 https://en.wikipedia.org/wiki/Angiogenesis#FGF
 https://en.m.wikipedia.org/wiki/Angiogenesis_inhibitor
 https://en.wikipedia.org/wiki/Tumstatin
 https://www.biooncology.com/pathways/vegf.html
 Cai, W., Chen, X. 2006. Anti-Angiogenic Cancer Therapy Based on Integrin avb3 Antagonism. Anti-Cancer
Agents in Medicinal Chhanabal, M., Jeffers, M., LaRochelle, W.J. 2005. Anti-Angiogenic Therapy as a
cancer Treatment Paradigm. Anti-Cancer Agents in Medicinal Chemistry 5 (2). Patrickemistry 407-428. D,
G.L. An Introduction to Medicinal Chemistry. New York: Oxford University Press, 2005

56. Reference
Molecular basis of angiogenesis and cancer
Tiziana Tonini1, Francesca Rossi1,2 and Pier Paolo Claudio*,1,3
1Department of Biotechnology, Temple University, Philadelphia, PA 19122, USA;
2Dipartimento di Pediatria, Seconda Universita’ di
Napoli, Italy; 3Dipartimento di Scienze Odontostomatologiche e Maxillo-Facciali,
Universita’ di Napoli ‘Federico II’, Italy Oncogene (2003) 22, 6549–6556
Tumor Angiogenesis
Basic Mechanisms
and Cancer Therapy
http://www.nature.com/onc/journal/v 22n/42/lluf/1206816 a.html
https://en.m.wikipedia.org/wiki/Angiogenesis
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2901818/
(https://en.wikipedia.org/wiki/Tumstatin)
http://www.tititudorancea.org/z/prolactin_16_kd_fragment.htm