Cancer Cells Adhesion, migration and Metastasis cams ,migration ,metastasis ,integrins ,cadherins ,selectins ,ig-sf ,cd44 ,rho gtpase family ,mtor

1. Dr. Ramez Wannous
Qussai Abbas
Kinda Sharrouf
Rasha Salman
Ali Salman

2. What is metastasis?
▷ Metastasis is the process by which a
tumor cell leaves the primary
tumor, travels to a distant site via the
circulatory system, and establishes a
secondary tumor
▷ Ability of malignant cells to invade
into lymphatics, blood vessels and
cavities and spread to distant sites.
▷ Cells must be able to invade out of
channels and grow at distant site.
2
In Situ
Cancer
Basement
membrane
Invasive cancer
Blood vessel

3. Types of metastasis
Primary
the site
where the
malignant
neoplasm
arises eg.
Breast.
Secondary
metastasis
eg. breast
carcinoma
that has
spread to
another
organ
3

4. 3
2
1Lymphatics
(lymph nodes)
Blood vessels
(lung, liver, bone and brain)
Coelemic spaces
What are the
routes of
metastasis?

5. Reason for organ selectivity
Mechanistic theory:
determined by the
pattern of blood flow
“Seed and soil” theory:
the provision of a fertile
environment in which
compatible tumor cells
could grow

6. Determining factors
Appropriate growth factors or
extracellular matrix
environment
Compatible adhesion sites
on the endothelial lumenal
surface
Selective chemotaxis at
which the organ producing
some soluble attraction
factors to the tumor cells

7. Diversity in
tumor-cell
migration

9. Protrusion1
Contraction
Adhesion
Detachment
2
3
4

11. Rho GTPase family
Cdc42
Rac1
RhoA

13. Protrustion of the leading edge
Formation of these structures is driven by spatially- and
temporally-regulated actin polymerization at the leading edge
Growing actin filaments connect to adaptor proteins and push the cell membrane in an outward direction
Filopodia
Lamellipodia
Invadopodia

14. Actin polymerization

16. Cancer Cells Adhesion and Metastasis
CELL–CELL ADHESION CELL–MATRIX ADHESION

17. Cancer Cells Adhesion and Metastasis
▷ Since cellular motility is an essential part of
cancer metastasis, and adhesion and de-
adhesion (detachment) are prerequisites for
cellular motility, cell adhesion is critical for
cancer metastasis.
▷ Further, cell adhesion is not just a way to link
cells or link cells with the ECM, but it also
serves as a mechanism to activate cell
proliferation and survival pathways.
▷ Adhesion is primarily achieved through a group
of cell adhesion molecules (CAMs).

18. CAMs
CAMs are surface
glycoproteins that are
typically
transmembrane
receptors made up of
three domains:
intracellular domain,
transmembrane
domain, and
extracellular domain.

19. Integrins
Cadherins
Ig-SF
CD44
Selectins
Cancer Cells Adhesion and Metastasis
CAMs:

20. Cancer Cells Adhesion and Metastasis
1- Integrins
Integrins are responsible for cell–ECM adhesion
Glycoprotein family that form
heterodimeric receptors for ECM
molecules
Laminin
(LN)
collagen
(Col)
Fibrinogen
Vitronectin
(VN)
Fibronectin
(FN)

21. Cancer Cells Adhesion and Metastasis
They are composed of α and β subunits with non-covalent bonds connected to each
other.
1- Integrins
There are at least 19α and 8β
subunits that dimerize to yield
different integrin heterodimers
with distinct ligand binding and
signaling properties.

22. Cancer Cells Adhesion and Metastasis
1- Integrins
The intracellular domain is linked to cytoskeleton
through intracellular focal adhesions (FAs).
FAs are supramolecular complexes formed by more
than 150 different proteins, including kinases,
scaffold, and adaptor proteins, as well as actin
linking proteins.
FAs also mediate intracellular signaling pathways
and are dynamic structures which assemble,
disperse, and recycle during cell migration .

23. Cancer Cells Adhesion and Metastasis
1- Integrins

24. Cancer Cells Adhesion and Metastasis
1- Integrins
During cancer differentiation and metastasis processes, up-regulation of integrins
has been linked to cancer invasiveness. The subunits α3, α5, α6, αv, β1, and β3 are
expressed in metastatic cells and can be considered as indicators for metastasis.
integrins are an
attractive target for
cancer therapy

25. Cancer Cells Adhesion and Metastasis
Integrin antagonists:
The α5β1, αvβ3 and αvβ5 integrins are widely expressed in different cancers
and recognize the tripeptide Arg-Gly-Asp (RGD) motif present in several ECM
proteins .
The first small molecule integrin antagonist developed was cilengitide which
is a cyclic peptide belonging to the RGD-peptide family. Cilengitide binds to
the integrin β chain and prevents the interaction of integrins with their
endogenous ECM ligands.
1a-RGD
ATN-161
1- Integrins

26. Cancer Cells Adhesion and Metastasis
2- Cadherins:
Cadherins are a superfamily of transmembrane glycoproteins mediating homophilic
(same type of cells) cell–cell adhesion.
More than 20 members of the cadherin molecules have been reported with cell type-
specific expression manner.
Two cadherins of the same type from adjacent cells interact in a noncovalent manner
to hold two cells tightly together.
E-cadherins in epithelial cells, N-cadherins in
mesenchymal cells VE-, P-, and R-cadherins in
vascular endothelial, placental, and retinal tissues,
respectively.

27. Cancer Cells Adhesion and Metastasis
2- Cadherins:
The intracellular domain of E-cadherin is linked to cytoskeleton (α-actinin, vinculin,
and actin cytoskeleton) through linker proteins (catenin complex: α-catenin, β-
catenin, γ-catenin, and p120 catenin).
Formation of an intact E-cadherin–catenin complex not only stabilizes cell–cell
adhesion, but also triggers downstream signal transduction, including Rho GTPases,
PI3K, and MAPK, as well as other pathways.

28. Cancer Cells Adhesion and Metastasis
2- Cadherins:
Down-regulation or decreased levels
of E-cadherin is an essential event for
EMT and has been found in metastatic
cancer cells.
In contrast N-cadherin, which is
expressed in stromal cells has been
found to be increased in prostate
cancer, breast cancer, and liver
cancer.
The critical roles of N-cadherin in
tumor cell adhesion and migration
make the protein an attractive target
for cancer therapy.

29. Cancer Cells Adhesion and Metastasis
2- Cadherins:
N-cadherin inhibitors:
The first synthetic N-cadherin antagonist, a linear decapeptide (N-Ac
LRAHAVDVNGNH2), was described in 1990 Since then, several types of N-cadherin
antagonists have been reported.
ADH1 (Exherin) was the first N-cadherin antagonist that entered clinical trials.
ADH1 selectively and competitively binds to N-cadherin and blocks its function.
ADH1 has been tested in a phase II clinical trial as a monotherapy and in various
phase I combination trials with cytotoxic drugs such as docetaxel, carboplatin,
capecitabine, and melphalan.

30. Cancer Cells Adhesion and Metastasis
3- Selectins:
Selectins are vascular cell adhesion molecules (VCAMs) involved in adhesive interactions of
leukocytes, platelets, and endothelial cells that mediate leukocyte trafficking and hemostasis.

31. Cancer Cells Adhesion and Metastasis
3- Selectins:
Reports showed that at least one selectin
(P, L, or E) is capable of binding to any
human carcinoma, which demonstrates
the potential of selectins to mediate
contacts with tumor cells within
vasculature.

32. Cancer Cells Adhesion and Metastasis
Selectins inhibitors:
Selectins have been implicated in mediating contacts
with tumor cells within vasculature. Inhibition or
downregulation of E-selectin expression results in
attenuation of liver metastasis. .
STMC hexasaccharide is an in vivo effective inhibitor
of P-selectin with antimetastasis activities in animal
models.
3- Selectins:

33. Cancer Cells Adhesion and Metastasis
4- Ig-SF:

34. Cancer Cells Adhesion and Metastasis
5- CD44:
• CD44 members have a single pass transmembrane
glycoprotein involved in cell–cell, cell–matrix
adhesion, and cell signaling.
• CD44 proteins also regulate growth,
differentiation, survival, and migration, which are
all involved in tumor development and metastasis.
• The most important property of CD44 is its ability
to bind HA, a vital factor for the metastatic
process.
• Therefore, inhibition of HA binding to CD44
appears to interfere with events that are critical
for tumor development like angiogenesis,
apoptosis inhibition, and invasion.

36. Rho GTPase family
Cdc42
Rac1
RhoA
Activationof Cdc42
triggersactin
polymerizationand
bundlingtoform
filopodia.
Activationof Rac1
promotesactin
polymerization
leadingtoformation
of lamellipodia

37. RhoA

38. Contraction & cell movement
Key targets of activated RhoA:
1- Formin

39. Contraction & cell movement
Key targets of activated RhoA:
1- Formin

40. Contraction & cell movement
2- Rho-dependent kinase (Rock)
Key targets of activated RhoA:

41. Contraction & cell movement
2- Rho-dependent kinase (Rock)
Key targets of activated RhoA:
༰ LIM kinases and cofilin
directly phosphorylate and inactivate
members of the cofilin family, resulting
in stabilization of filamentous (F)-actin.
༰ PTEN and IP3 kinase…

43. On the basis of the structure-function information of Rac interaction with
GEFs, in a computer based virtual screening we have identified NSC23766, a
highly soluble and membrane permeable compound, as a specific inhibitor of
a GEF binding to Rac, therefore, inhibiting Rac activation by these GEFs.

44. Different enzymes can modify
stroma allowing cells to break
through basement membrane and
spread
Required for a controlled
degradation of components of the
extracellular matrix (ECM)
The proteases involved in this
process are classified into serine-,
cysteine-, aspartyl-, and
metalloproteinase.
Altered
cadherin
Altered
integrin
Basement
membran
e
Matrix degrading enzymes
Fibroblast
Growth
factor
Cancer
Cells
Matrix Degrading Enzymes

45. 26 members, subdivided into 4
groups, based on their structural
characteristics and substrate
specificities
Soluble and secreted groups;
collagenase, gelatinase and
stromelysins matrilysine
Membrane type (MT-MMP) group
are anchored in the plasma
membrane.
A zinc ion in the Active Centre of the
protease is required for their
catalytic activities
Matrix Degrading Enzymes
Matrix MetalloProteinases (MMP):

46. Matrix Degrading Enzymes
Regulation of MMP
MMP is controlled by an increased
expression on a transcriptional level.
MMPs are calcium-dependent proteases,
which are synthesized as a inactive
proenzymes and are activated by the
cleavage of a propeptide.
MMP activity is regulated by specific
inhibitors, the tissue inhibitors of MMP
(TIMPs).
MMP2 and MMP9, which cleave type IV
collagen the major constituent of basement
membrane, are believed to be of special
importance

47. ▷ Serine protease involved in ECM
degradation are plasmin, plasminogen
activators and cathepsin G.
▷ Plasmin is believed to be the most
important serine protease, firstly because
its ability to degrade several matrix
components like gelatin, fibronectin or
laminin, and secondly by the possible
activation of numerous proforms of MMPs
by propeptide cleavage.
▷ Plasmin is synthesized in its inactive
proform, plasminogen, which can be
converted to plasmin by plasminogen
activator.
▷ Two main types : urokinase (uPA)
and tissue (tPA).
▷ uPA is bound to the surface of
tumor cells by means of a specific
receptor (uPAR)
▷ There are specific inhibitors (PAI-1
and PAI-2) for the PA
Serine proteases:
Matrix Degrading Enzymes
Plasminogen activator:

49. Matrix Degrading Enzymes
Inhibition of proteases
• Inhibition of MMPs was considered to be a very promising
approach and was studied in a variety of clinical trials as
therapy for various types of cancers.
Unfortunately, those trials were largely unsuccessful
• It has been suggested that the
combination of a MMP inhibitor with other
chemotherapeutic agents would probably
yield a better therapeutic outcome
• The disappointing outcomes
development of drug resistance by the tumor cells
lack of sufficient specificity of the inhibitors and
changes in the cancer cell migration and invasion
(amoeboid cell migration through mesenchymal-
amoeboid transition)
• Small molecule MMP inhibitors, which are grouped
chemically as hydroxamates, thiol-based
analogs, pyrimidine-2,4,6-triones and mABs.

50. Regulation of pI3k pathway :
• PTEN is one of the most frequently
mutated tumor suppressors in human
cancer.
• It reduces rates of migration through
several mechanisms. One recently
identified mechanism is through its
effects on PtdIns(3,4,5)P levels .which
have downstream effects on Rac and
Cdc42 signaling

51. MTOR:
4E-BP1
S6K1
Akt
GTPase
FAK
PKCa
SGK1
Protein synthesis
Metabolism
Cell motility and
invasion
Cell survival
Cell motality and
invasion
Known
effector
molecules
Functions
 Ser/Thrproteinkinase
 multi-domain protein
 Phosphatidylinositolkina
se-related kinase (PIKK)
MTORC1 MTORC2

52. hank ou!
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