Terrible class Flashcards
what is the cause of 90% cancer related mortality
metastasis
what are the 5 major steps in metastasis
-invasion and infiltration of surrounding normal host tissue
-release of neoplastic cells
-survival in the circulation
-arrest in the capillary beds of distant organs
-penetration of the lymphatic or blood vessel walls followed by growth of the disseminated tumor cells
true or false: only a small % of circulating cancer cells will form metastases
true
primary to secondary tumor site test
-cell detachment
-invasion of stroma
-intravasation
-migration
-extravasation
-establishment of metastases (in secondary organ site)
what happens in cell detachment
-emt
-matrix degrading proteinase (augment)
-growth factors and receptors (egfr, igf1r and tgf) go up
-adhesion molecules go down
-proteinase inhibitor go down
what happens in migration
-endothelial cell and adhesion molecules go up
what happens in extravasation
-selectin ligans change
-integrins and matrix degrading proteinasa
what happens in establishment of metastases
-interaction with local micro environment
-cell-cell adhesion molecules go up
-autocrine and paracrine growth regulatory factors (igf1, igf1r) go up
in vivo models
-analysis of surgical biopsies
-histopathology, genome, transcriptome, proteome
-animal tumor models (induction, transplantation, spontaneous and experimental metastasis)
-transgenic mice
-human tumor xenographs
-circulating tumor cells aka liquid biopsiesi
in vitro models
-cell lines
-reconstitutes tissues like vessels
-extracellular matrix models
-genetically altered cells
-PDX/organoids/slices
how to know that the poly metastasized
-the basal membrane is degraded
microinvasion of tumor
true or false: there can be hyperplasia without metastasis
true
what is the key to aquisition of a motile phenotype
epithelial to mesenchymal transition
what is downregulated during loss od apico basal polarity
e-cadherins and epithelial integrins
what is up regulated during gain of mesenchymal proteins
-n cadherins
-mesenchymal integrins
-vimentin
before transition what happened
-cell adhesion by adherens/tight junction
-apical basal polarity
-non migratory
-express epithelial markers like ecadherins
after emt what happened
-spindle shaped morphology
-loss of cell junctions
-change in cell polarity
-cleavage and invasion of basal lamina
-migration along fibronectin matrix
-express mesenchymal markers like n cadherin
what does fibronectin do
migration tracks
which ligans make homophilic interactions
-e cadherins and ig-superfamily
-cams aka N cams and type III fibronectin repeats
which ligans make heterophilic interactions
-mucins like CAMs and P selectins
-integrins and fibronectin
what is the binding sites of e cadherins
ca2+ binding sites
what does E selectin do
expressed on endothelial cells mediated tumor cell attachment in blood vessels
what is the hallmark of EMT
reduced E cadherins expression
where are N cadherins
-neural
-neurons, muscle, endothelial cells
where are e caherins
-epithelial cells/tissues
where are P cadherins
-placenta
where are r cadherins
retina
where are ve cadherins
-vascular endothelial cells
what are the roles of cadherins
-mediate calcium dependant homotypic cell-cell adhesion
-during embryogenesis mediate cell sorting
-formation of intercellular junctions like adheren, gap, tight, desmosomes
-establish cell polarity
-inhibit apoptosis
-activate or inhibit growth factor receptors like tyrosine kinases
what is a catetin
a bridge to actin cytoskeleton
what is eplin
epithelial protein lost in neoplasia links a catetin and actin
what does p120 do
a src kinase substrate, stabilizes e cadherin and links it to the other signaling systems
what is b catenin
a transcription factor in wnt signaling
what does HAV containing peptides do
-bind to eachother
-can disrupt adhesion and trigger cell migration
well differenciated, poorly invasive adenomas express what?
high E cadherin levels
invasive carcinomas express what?
have reduced e cad levels
invasive carcinomas have reduced e cad levels why?
transcriptional repression/inactivation dna methylation , mutations or post transcriptional events
e cadherins levels and the stability of e cad catenin complex can be de regulated through what?
phosphorylation of e cad, b catenin or p120 catenin by activated receptor tysosine kinases
e cad can negatively regulate what?
rtk
a reduction in e cad levels increase what????
cell motility, invasion and triggers b catenin/lymphoid enhancer binding factor: lef1 regulated transcription
what are the 3 classes of molecules in the ecm
-structural proteins (collagens and elastins)
-protein polysaccharide complexes to embed the structural proteins (proteoglycans)
-adhesive glycoproteins to attach cells to matrix (fibronectins and laminins)
what is the ecm
-web of proteins and carbohydrates at cell surface
-outside plasma membrane
-connected to cytoskeletal fibers and transmembrane proteins
18 a subunits and 8b subunit of integrins associate to form what….
multiple non-covalently bound heterodimeric transmembrane receptors
which endotelial cells receptors mediate angiogenesis
fibronectin
vitronectib
osteopontin
tenascin
integrin signaling cascade steps
-step 1: inside out signaling: an unbending and elongation of the dimer
-step 2: outside in signaling : separation of the 2 cytoplasmic abilities
true or false: integrins associate with receptor tyrosine kinases to amplify survival and growth signals
true
ex: avb3 with IR, vegfr and pdgfr and a5b1 with egfr
integrin signaling involves ….. with other regulatory signaling pathways
crosstalk
-there is focal adhesion
which kinases can mediate emt anbd are involved in different stages of metastasis
receptor tyrosine kinase
which rtks are already a dimer
insr
igf1r
irr
ras cascade
-growth factor binding
-receptor dimerization
-receptor autophosphorylation
-binding of adaptor protein and gef protein at membrane
-activated ras aka ras gtp activated a protein kinase cascade
-phosphorylated transcription factors ebter the nucleus to change gene expression
main roles of activation of rtks in human tumors
-autocrine loop
-amplification
-constitutive activation by point mutation
-genomic rearrangemnet- constituvely dimerized fusion protein
what is emt
-epithelial mesenchymal transition is an essential process during devlopment and is replicated in early stages of malignant progression
what are snail 1 and 2
-slugs are key regulators of the emt program linking wnt, tgfb and notch signalling
what does snail upregulate
-fibronectin
mmp
lef 1
what does snail down regulate
e cadherin
20x increse in snail 1 in patients with what
metastatic relative to non metastatic hcc
true or false: nfkb is an inflammatory mediator that downregulates snail
false it up regulates it
what is gsk 3b
glycogen synthase 3b is a destabilizer of b catenin (narking it for proteosomal degradation), smad, notch 1 and snail which is at the crossroad if severak signaling pathways
what does sinc finger e box binding homeobox proteins zeb1/2
represses e cad and increase mmp expression
tgfb signalling is a major inducer of what
emt
true or false: tgfb1 is a transcriptional repressor of e cad
true
mouse mammary epithelial cells undergo emt in response to what and how can it be blocked
tgfb1 can be blocked by n cad shrna
GSK-3 b - guardian of epithelial phenotype through its negative regulatory effect on
…..
b-catenin, SMAD, Notch1
and Snail
GSK-3
b phosphorylation by AKT releases t…….
his inhibition, stabilizing these TF and targeting them to the nucleus for transcriptional activation of EMT drivers
Signaling pathways that activate AKT (RTK, integrins)
or SMAD (TGF b) can initiate ….
EMT
true or false: tgfb only induces emt
false, it also regulates the tumor microenvironment
E-N Cadherin switching occurs in many cancers, is probably a …..
late event and can influence many cellular activities
effects of e-n cadherin switching
-increased detachment (loss of sorting)
-increased motility
-increased survival
Circulating soluble N-cadherin has been observed in the serum of cancer patients and shown to stimulate …..
angiogenesis and the migration of endothelial cells by associating with fibroblast growth factor receptor (FGFR)
what does e cadherin INHIBIT
-igf, egf and fgf receotir signaling
WHAT DOES N CADHERIN upregulate
expression induced by tgfb and b catenin
Non metastatic carcinoma cell (MCF-7) become metastatic upon
….
N-cadherin overexpression
N-cadherin silencing in pancreatic carcinoma cells renders them…..
non-invasive and non-metastatic
Transgenic expression of N-cadherin does not cause …..
tumorigenesis and does not alter tumor onset in mammary carcinoma models (Polyoma middle T or Neu) although it could accelerate metastasis
Cadherin switch is a late event, not oncogenic but promotes…..
invasion and metastasis.
what are the different modes of tumor migration
-MESENCHYMAL
-mesenchimal multicellular
-solid strand
-outward pushing tumor
steps of individual cell migration
-pseudopod protrusion adhesion and traction force generation
-focalized proteolysis
-actomyosin contraction
-rearend retraction s
steps of collective cell migration
-same steps as individual
0multicellular group ecm remodeling along interface macrotract
invasion into surrounding tissue requires that:
-tumor cells traverse several tissue compartments comprised of cells seperated bu the ecm
-destructive enzymes are secreted that can locally degrade the ecm
-tissue architecture breaks down, enabling the tumor to expand, invade neighboring blood vessels and spread to distant sites
true or false: invasion is a requirement at all stages of the metastatic process
true
what are the classes of proteinases
serine
cysteine
aspartic
metallo
what are exampkes of metallo proteinases
collagenese and stromelysin
true or false: mmps are sinc and calcium dependent enzymes
true
who are the normal physiologic mediators of matrix degradation
mmps
true or false: mmps share a high degreee of structure homology but differ in substrate specificity
true
what are the sub classes of mmpa
collagenases
-gelatinases
-stromelysins
-mt-mmps and other
true or false: mmps play a hige role in invasion and metastasis
true
how many genes encode for mmts
23 in humans
what is special in mmp 2 and 9
rhey have fibronectin type 2 repeats
they are gelatin binding
what do mmp 2 and 9 do when you ko them
metastasis and angionesis reduced in KO mice
where are located mt mmps
transmembrane
what are the minimal domains of mmps
mmp 7 and 26
what is mmp1
it is a standard domain
The MMPs are tightly regulated at multiple levels
Gene expression
Activation
Inhibition
Proteolytic cascades and feedback mechanisms (MMP can cleave plasminogen) to ensure tightly regulated tissue processing
what mechanism regulate mmps
the cysteine switch
-it has a pro domain that sirts on top of the catalytic domain rendering the enzyme inactive
-becomes active when the pro domain is displaced
MMP-2 KO mice :
Blockade of experimentally induced pancreatic
carcinogenesis; suppression of angiogenesis and tumor growth ;
delayed mammary gland differentiation; mild growth retardation.
MMP-9 KO mice :
Blockade of experimentally induced skin
carcinogenesis; suppression of experimentally induced pancreatic
carcinogenesis; decreased experimental metastasis
MMP-11 KO mice:
Suppression of experimentally induced mammary carcinogenesis; decreased tumor cell survival and growth
MMP-14 KO mice:
Reduced collagen turnover; defective angiogenesis
MT4-MMP in breast cancer cells involved
in …..
vessel dissociation and intravasation
increasing metastasis.
what is the invadopodia
are actin-rich protrusions of the plasma membrane that are associated with degradation of the extracellular matrix. They play a crucial role in cancer cell invasion and metastasis
what is adam
disintegrin and metalloproteinase – mostly
transmembrane
WHAT IS ADAMT
disintegrin and metalloproteinase with thrombospondin motifs -secreted
what is the cr region on the adams
hypervariable region, site of molecular reactions
what are the dis and egf regions
integrin binding substrate specificity
what do the adms participate in
ecm proteolysis and engance cancer cell growth
21 known human ADAMS Can mediate…..
Proteolysis of BM proteins E-Cad degradation Processing of GF, cytokine
precursors
ADAM10 and ADAM 17 expression levels
increase in
CRC liver metastases ADAM12 –ectodomain shedding of VE-CAD
adam10 is alssociated with what
e cadherin
what is adam17 associated with
protnfa, proamphiregulin and notch
inhibitors of mmps in the plasma
a2-macroglobulin
a1-proteinase inhibitor
a1-chymotrypsin
α2-antiplasmin
-produced in liver, actibe in plasma and non specific
what do TIMPS 1-4 do
-inhibitors of mmps in plasma
- products of separate genes
NT domain of 125 a.a. and CT domain of 65 a.a.
each stabilized by s-s bonds
produced by tumor (or host cells)
highly specific
act regionally
true or false timp can bind to inactibe forms of mmp
it can also bind to the active form of mmp
which cell do mmp2 and plasmin bind to
on tumor cells
he tumor microenvironment is critical and contributes to proteolytic cascades of….
MMP-2
New blood vessels provide ….
a source of nutrients and oxygen and a venue for dissemination
the angiogenic switch is necessary for what
tumor growth and metastasis
what happens in neovascularization
-makes rapid tumor growth possible bu supplying ocygen and nutrients and removing waste
-facilitates metastasis
angiogenesis can be triggered by what
tumor or microenvironmnet derived factors
Angiogenesis and lymphangiogenesis are orchestrated through interplay between
GF (VEGF), cytokines (TNFa) and integrins
ECM collagens are a source of ….
angiogenesis-inhibitor
-inhibitors are built in the invasive process
linical and experimental evidence
support Paget’s ……hypothesis
…..
-“seed and soil”
-Tumor-intrinsic and extrinsic determine the site of metastases.
-basically the type of tissue will determine the type of cancer
true or false: gene signatures can predict the site of metastasis and outcome
yeah
tumor cell movement toward a target organ is mediated by what
cytokineswha
t what is the role oc cxclr4-6
plays a role in tumor cell extravasation crosstalk with tumor associated stroma
where is found cxcr4-6 and mcp4
multiple organs
where is ccl20 found
in liver
where is ccl21 cound
lymph nodes and lung
time line of the early steps in organ colonization
-interaction with platelets 0-2 min
-interaction with neutrophils 2 min to 7-24h
-interaction with monocytes and macrophages rest of the time
Tumor cells form
microthrombi with platelets,
this protects them from….
shear stress and NK-mediated
lysis.
-It is also a source of
TGF b and PDGF.
Microthrombi do not form in
P-selectin−/− mice and these
mice are protected from
metastasis
true or false: cells derived from the bone marrow precede tumor cells to the site of metastasis
true
Cells derived from the bone marrow (green) precede tumour cells (red) to the
lung, the site of metastasis. The bone-marrow cells create…..
a proposed ‘pre-metastatic niche’, and the tumour cells join them to form a metastasis.
Organs of future metastasis are selectively and actively ….
modified by the primary tumor before metastatic spread has occurred
Tumors induce the formation of microenvironments in distant organs that are conducive to
…….
the survival and outgrowth of tumor cells before their arrival at these sites. These
microenvironments are termed pre-metastatic niches (PMNs).
PMN formation is a ……. process resulting from the combined systemic effects
of tumour-secreted factors and tumor-shed extracellular vesicles
step wise process
PMN formation is initiated with local c….
changes such as the induction of vascular
leakiness, remodelling of stroma and extracellular matrix, followed by systemic
effects on the immune system
The development of new technologies and approaches to identify PMNs in
distant organ sites in patients could revolutionize cancer treatment and lead to pre-emptive treatments to hinder metastasis
what delivers the signals to theorgans abouy the cancer cell
exosomes
Exosomes produced by pancreatic cancer cells induce
a pre-metastatic niche in the liver
Exosomal integrin expression as a potential predictor of
-patient organ-specific metastasis.
-NED- no evidence of disease
-LR- locoregional disease
-POD-predictor of dissemination
In the target organ cancer cells (often) undergo…..
mesenchymal to epithelial transition (MET)
Re-expression of…. is required for establishment of liver metastases
type iv collagen
Metabolic adaptation is crucial for tumor cell ….
survival andgrowth in a secondary organ.
The metabolic landscape of each organ is …
unique
Tumor cells in a secondary site need to adapt….
metabolically to
the new organ site to produce ATP and to survive
Dormancy may also result from the inability of tumor cells to …
reprogram metabolically
true or false: in the target organ, some cells will enter a dormant state
true
