Transcript REUNION GUADALAJARA JUNIO 2011

CELULA MADRE EN CANCER DE
PROSTATA IMPLICACIONES CLINICAS
Y TERAPEUTICAS
Prof. Dr. L. M. Antón Aparicio
Jefe Servicio Oncología Médica
Complejo Hospitalario Universitario
Coruña
SUMMARY (I)
•
Normal prostate gland development requires many coordinated cellular process
through prostate stem cells, including epithelial proliferation, mesenchymalepithelial interaction, ductal branching morphogenesis, and ductal canalisation.
•
Stem cells are defined functionally as cells that have the capacity to self-renew as
well as the ability to generate differentiated cells. Stem cells can generate
daughter cells identical to their mother (self-renewal) as well as produce progeny
with more restricted potential (differentiation). Self-renewal is achieved by
symmetrical cell division while maintaining pluripotency; and this can be
modulated by extrinsic factors, transcriptional regulator, and effectors.
•
The regenerative capacity of prostate gland has been attributed to
stem/progenitor cells within adult prostatic epithelium. It was hypothesized that
the adult prostate contains stem, transit/amplifying, and postmitotic cells and that
the stem cells were androgen-independent for survival.
SUMMARY (II)
•
In the normal prostate gland epithelium exist at many stages a spectrum of cells
expressing a continuum of differentiation markers, biological properties, all them
beginning from stem/progenitor cells through multiple intermediate cell types
along different lineages to terminally differentiated cells.
•
There is now strong evidence that the stem cells of many tissues reside in
physically delineated as well as physiologically specialized structures termed
niches. Inside the niche, stem cells are often quiescent; outside the niche, stem
cells must either possess sufficient intrinsic factors to overcome differentiation or
succumb too much of fate. The signal that controls which daughter cell or an adult
stem cell remains as stem cell and which begins the process of determination may
be mediated through a number of signalling pathways including Wnt, Hedgehog
(Hh), Notch, Bone Morphogenic Protein (BMP), Oct-4.
•
The signal that controls which daughter cell of an adult stem cell remains a stem
cell and which begind the process of determination may be mediated through a
number of signalling pathways including, Wnt, Hh, Notch, Oct-4, BMP, JAK/Stat, or
other signalling pathways.
PROSTATE GLAND
The prostate is located at the base of the bladder in males, surrounding the urethra
(Cunha et al. 1987).
The gland is composed of tubules that have an epithelial compartment surrounded by
stromal cells that include fibroblasts, smooth muscle, and myofibroblasts.
1. The epithelium consists of two cellular compartments made up of three
mophologically, functionally, and molecularly distinct cell types.
1.a. Androgen-independent flat basal cells are attached to the basement membrane,
where they maintain the homeostasis of the organ and express the high-molecularweight cytokeratins (CK) 5 and CK14. A subpopulation of basal cells also expresses the
p53-family-related gene p63.
1.b. Luminal cells are CK8/18-positive androgen-dependent columnar cells that lay
above the basal layer facing the lumen of each tubule where they secrete prostatic
proteins.
1.c. Neuroendocrine cells reside largely in the basal compartment, where they secrete
neuroendocrine peptides such as synaptophysin and chromogranin A that support
epithelial viability (Bonkhoff 1998; Abrahmsson 1999).
1.d. A fourth population of epithelial cells, named transit-amplifying cells, that coexpress
basal (CK5) and luminal (CK8) markers (Isaacs and Coffey 1989), as well as prostate stem
cell antigen (PSCA) in later stages (Tran et al. 2002).
ADULT PROSTATE STEM CELLS
The existence of PrSCs was determined by the observation that the
rodent prostate can undergo up to 30 cycles of involution and
regeneration in response to androgen cycling (English et al. 1987).
Two prevalent models have emerged to explain how these PrSCs give
rise to the different cell types of the prostate.
1.
2.
The linear model prosposes that the PrSCs reside among the CK5positive basal cells, where they can differentiate into the doublepositive intermediate/transit-amplifying population and the
finally into the CK8-positive luminal phenotype (Isaacs and Coffey
1989; Hudson et al. 2001)
The branched model of differentiation where the luminal and
basal cells are in separate lineages, maintained by separate
progenitor cells.
Location of stem cells: niche.
Multiple growth factor and cytokins are involved in stem-niche interactions. These include SCF/Kit, SDF1/CXCR4, Jagged/Notch, Androgen/Receptor, etc. BMP4 is expressed in stromal cells, but the type of
receptor expressed in prostate stem cells is unknown. The Wnt signal is important for stem cell selfrenewal, but the Wnts present in the niche are unknown. The source is true for FGF and Hh.
Stem cell type
Cell type
Markers
UGS epithelium (embryonic)
Luminal cell
CK8, CK18
Basal cell
CK5, CK14, p63
Transitional/ Intermediate
CK19, GSTpi
Luminal cell/predominant
CK8, CK18,
Neuroendocrine cell
Chromogranin-A, Synaptophysin,
Neuron-specific enolase, Serotonin
Basal cell/predominant
subpopulation
CK5, CK14, CK19, p63, GSTpi
Basal cell /small fraction
CK5, CK8, CK14, CK18, CK19,
P63, GSTpi
Basal cell / subset
CK15, CK17, CK19
Prostate epithelium (adult)
CK: cytokeratin; GSTPi: Glutathione-S-transferase-pi.
Progenitor/stem cells in embryonic urogenital sinus epithelium and
adult prostate epithelium with their respective cell lineage markers.
Cell
lineage
relationships
in
adult
prostate:
basal
cells
(CK5/14/p63/CK19/GSTpi+/CK8/CK18-);
definitive
luminal
cells
(CK8/18+/CK5/14/p63-); embryonic-like cells co-expressing both luminal and
basal cell markers (CK8/18/14/5/p63/CK19/GSTpi+).
Cell type
Luminal epithelial cells
Characteristics
Androgen-dependent, more
differentiated, low proliferative
capacity, high apoptotic index.
Cell markers
, PSA, CK8, CK18
Refs.
36, 37, 38
Basal epithelial cells
Androgen-independent,
undifferentiated profile, high
proliferative capacity, antiapoptotic protein.
, CK5, CK14, CK15, p63,
Bcl-2
36, 39, 40, 41
Stem cells
Stem cells
Sca-1, CK5, p63, CD4af
CK5, CK14, CD133,
CD44, CD4af
22, 23, 41, 42
43, 44, 45
Sca-1+, CD4af+, CD34CK5, CK14, p63
CK8, CK18, AR
36
36
36
Murine prostate
Human prostate
Prostate progenitor/ /stem
cells
Stem cell markers
Basal cell markers
Luminal cell markers
Cells presents in prostate with characteristics and cell markers associated
Developmental proposed model that implicates the different prostate
gland epithelial cells genesis from stem/progenitor cells.
Prostate stem cell hierarchy.
Prostate epithelial cell hierarchy.The stem cells divide, give rise to a new stem cell –self
renewal- and more committed progenitor cells (early&late) for the functional exocrine
and neuroendocrine cell lineages; the exocrine lineage is critically dependent on DHT,
and in fact this population represents >90% of all epithelial cells in the adult prostate
gland
ORIGIN OF PROSTATE CANCER CELLS
The vast majority of prostate cancers are acinar-type adenocarcinomas, which are defined by the proliferation of malignant
luminal-type cells and a loss of basal cells.
The traditional view is that prostate cancer arises from mature luminal cells of the prostate gland.
A subgroup of luminal cells, which are typically characterized
by the expresion of a transciption factor called NK3 homeobox
1 (Nkx3-1), also survive androgen depletion.
A majority of castration-resistant cells have a basal anatomic
location and express basal-cell markers.
Castration-resistant Nkx3-1 (CARN) cells express the androgen receptor and the luminal-cell marker CK18 and do not express
basal-cell markers.
1. CARN cells could give rise to basal, luminal, and
neuroendocrine cells after androgen was restored.
2. CARN cells were able to regenerate ducts and self-renew.
3. After the deletion of Pten, cells with a basal phenotype can
initiate prostate cancer in the mouse (Figure 1)
4. Deleted Pten (a tumor-suppressor gene) in CARN cells and
observed rapid carcinoma formation after androgen-mediated
regeneration
If prostate cancers indeed originate from different cell types (e.g., the basal or luminal compartment), the resulting tumors
might have different genetic profiles, biologic behavior, and therapeutic responses.
Proposed model of the cellular events associated with the initiation and progression of
prostatic cancer.
Ontogeny of prostate caner stem cells. In primary human prostate
tumours three classes can be discriminated; those with a minority of cells
(candidate stem cells) similar to the early- or late progentors, and the preterminally differentiated phenotype.
Hh
WNT
WNT
• Wnt signaling pathways regulate a variety of processes, including cell
growth, development and oncogenesis (Polakis 2000)
• Wnt regulate the stability of -catenin, a Key component of Wnt signaling
• A protein-protein interaction between th AR and -catenin has been
identified (Yang 2002).
• -catenin act as an AR coactivator, increasing AR-mediated transcription
(Truica 2000).
• Wnt 3 a plays an important role in androgen-mediated transcription and
cell growth (Verras 2004).
• Wnt 3 a induces AR activity in the absence of androgens or ehances AR
activity in the presence of low concentrataions of androgens (Verras 2004)
CONCLUSION
AR: Wnt crosstalk adds an additional layer of complexity to the Wnt
pathway´s role in prostate biology
Notch
NOTCH
•
•
•
•
•
•
•
•
•
Notch is part of an evolutionarily conserved signaling pathway that regulates cell
differentiation, proliferation, an growht (Mumm Skopan 2000)
Notch signaling has been reported to be a requirement for normal murine prostate
re-growth and branching (Wang et al 2004, 2006).
Notch-1 signal was seen selectively in the epithelium surrounding the lumen of the
budded ductal epithelial units. (Shon et al 2001).
Notch-1 expression is associated with basal epithelial cells in prostate (Gluene et
al, 2001).
The Notch-1 cells appeared to correlate with the population of the bsal cells
during prostatic develpment. (Shon et al 2001).
Notch-1 signaling may act to repress AR signaling (Belandia et al 2005)
Endrogenous Nothc-1 regulates PTEM tumor suppressor gene (Whelan et al 2009).
Notch-1 signaling has been linked with regulation of prostate tumor cell motility
(Scorey et al 2006).
Notch-1 signaling is lost in prostate adenocarcinoma (Whelan et al 2009)
CONCLUSION
Notch-1 signaling may contribute to the accumulation of genetic alterations that esult
in prostate cancer throngh reduced PTEN gene expressions.
CROSS TALK / CROSS-REGULATION
NOTCH activity inhibits prostate progenitor function ( Shahi et al 2011)
• The inhibitory role of Notch signaling toward proliferation of prostate
epithelial cells is via PTEN induction (Barth et al 1999)
Wnt signaling results in proliferation of immature prostate progenitors (Shahi et al
2011)
• The reported mechanism describe the induction of AR-mediated transcription
and enhances prostate cancer cells growth (Verras et al 2004)
CONCLUSIONS
• The ability of Wnt pathway to promote adult stem cell proliferation and selfrenewal is associated with is ability to influence the Notch signaling pathway
which is upregulated as a result of Wnt pathway induction. (Reya 2003,
Duncan 2005)
• Wnt and Notch pathways have interrelated opposing roles on prostate
progenitor cells proliferation and differentiation(Shahi et al 2011).
ANDROGEN RECEPTOR
• The androgen signaling pathway, which is mainly
mediated through the AR is importants for the normal
and neoplastic development of prostate cells (Gelmann
2002).
• Multiple mechanisms by which prostate cancer cells
progress to androgen-insensitive stages have been
reported: AR mutations, anplification (Balk 2002).
• In particular, it has been shown that PI3PK/AKt and
PTEN regulate AR. Mediated transcription (Sharma
2002, Wen 2000).
• Wnt and Notch are able to stimulate AR. Mediated
transcription, having interrelated opposing roles on
prostate progenitor cell proliferation and
differentiation (Shahi 2011).
Pathway
Wnt
BMP
Component Function
WNT11
Ligand
SFRP2
Ligand
inhibitor
SFRP4
BMP2
BMP2
Ligand
inhibitor
Ligand
Ligand
BMP3
BMP4
BMP4
Ligand
Ligand
Ligand
BMP4
Ligand
BMP5
BMP6
Ligand
Ligand
BMP6
BMP7
BMP9
SMAD4
Ligand
Ligand
Ligand
Intracellular
effector
Intracellular
effector
SMAD8
Sample
Prostate tumor cell lines
Expression
Androgen-dependent: high with androgens;
inhibited without androgens
Mouse prostate, early/advanced stages Activation/
of development
down-regulation in early/advanced
stages respectively
Rat prostate ablation and DHTRepressed
dependent re-growth
Normal/tumor prostate tissues
Expressed in both tissues
Benign/tumor
Decreased in tumor tissue
tissues
Normal/tumor prostate tissues
Expressed in both samples
Normal prostate development
Expressed
Normal/tumor prostate tissues
Expressed in both but predominantly
expressed in normal prostate
Prostate tumor cell lines
Induction under WNT3A, WNT5
administration or
DKK1 deletion
Normal/benign prostate tissues
Upregulated in benign tissue
Prostate tumor cell lines
Induction under WNT3A, WNT5
administration or
DKK1 deletion
Normal/tumor prostate tissues
Expressed in both tissues
Normal prostate development
Expressed
Prostate tumor
Decreased or absent
Benign/tumor
Decreased in tumor tissue
tissues
Normal/benign/
Expressed in normal/benign; absent in
tumor tissues
tumor
Refs.
71
63
64
73
78
73
75
73
72
74
72
73
82
79
78
78
Notch
NOTCH1
NOTCH1
NOTCH1
NOTCH1
NOTCH2
NOTCH2
NOTCH3
NOTCH4
JAG1
JAG1
JAG2
DLL1
DLL1
DLL4
SEL1L
DTX
(Deltex)
HES1
HES1
HEY1
Receptor
Receptor
Normal prostate development
Overexpressed in response to BMP7
Rat prostate ablation and DHTRepressed in rat ventral prostate
dependent re-growth
Receptor
Human normal prostate cell lines:
Expressed
PrEC, BPH-1, PNT2, RWPE-1,
PZHPV-1
Receptor
Mouse prostate ablation and androgen- Induction after castration. Return to
dependent re- growth
normal levels during re-growth
Receptor
Human normal prostate cell line: PNT2 Expressed
Receptor
Rat prostate development
Expressed in specific areas of stromal
mesenchyme
Receptor
Human normal prostate cell line: PNT2 Not expressed
Receptor
Human normal prostate cell line: PNT2 Not expressed
Ligand
Human normal prostate cell lines:
Expressed
PrEC, PNT2
Ligand
Rat prostate ablation and DHTRepressed in rat ventral prostate
dependent re-growth
Ligand
Human normal prostate cell lines:
Expressed
PrEC, PNT2
Ligand
Human normal prostate cell lines:
Expressed
PrEC, PNT2
Ligand
Rat prostate development
Expressed in specific areas of stromal
mesenchyme
Ligand
Human normal prostate cell line: PrEC Not expressed
Inhibitor
Rat prostate development in response Induced in rat ventral prostate
to DHT
Intermediary in Human normal prostate cell line: PNT2 Not expressed
signaling
Intermediary Human normal prostate cell line: PNT2 Expressed
target
Intermediary Normal prostate development
Inhibited in presence of BMP7
target
Intermediary Human normal prostate cell lines:
Expressed
target
PrEC, RWPE-1, PZHPV-1
82
83
83
85
83
88
83
83
83
64
83
83
88
83
64
83
83
82
83
Hedgehog SHH
SHH
Ligand
Ligand
Mouse UGS
Developing mouse prostate
SHH
IHH
DHH
PTCH1
Ligand
Ligand
Ligand
Receptor
Human fetal prostates
Mouse prostate development
Human fetal prostates
Mouse developing prostate
PTCH1
Receptor
Rat developing prostate
PTCH1
PTCH1
PTCH2
Receptor
Receptor
Receptor
Human fetal prostates
Adult prostate
Rat developing prostate
PTCH2
SMO
Receptor
Trans-membrane
effector
Intracellular
effector
Intracellular
effector
Intracellular
effector
Intracellular
effector
Intracellular
effector
Intracellular
effector
Intracellular
effector
GLI1
GLI1
GLI1
GLI2
GLI2
GLI3
GLI3
80
91
Human fetal prostates
Human fetal prostates
Expressed in epithelial cells
Expressed in epithelial cells in tips of
buds
Expressed in epithelial ducts
Up-regulated in SHH nulls
Expressed in epithelial ducts
Expressed in mesenchyme around tip
buds
Expressed in mesenchyme stromal cells
adjacent to epithelium of tip buds
Expressed in epithelial ducts
Not expressed in epithelial basal cells
Expressed in mesenchyme stromal cells
adjacent to epithelium of tip buds
Expressed in epithelium and stroma
Expressed in epithelial ducts
Mouse developing prostate
Mesenchyme around tip buds
91
Human fetal prostates
Expressed in epithelial ducts
97
Adult prostate
Not expressed in epithelial basal cells
98
Mouse developing prostate
91
Adult prostate
Expressed in mesenchyme around tip
buds
Not expressed in epithelial basal cells
Mouse developing prostate
Expressed throughout mesenchyme
91
Adult prostate
Not expressed in epithelial basal cells
98
97
95
97
91
92
97
98
92
97
97
98
Scheme showing the possible mitogenic and antiapoptotic cascades induced through the
EGF–EGFR, hedgehog, Wnt and other growth factor signaling pathway elements co-localized
in caveolea.
Scheme showing the possible oncogenic cascades involved in
the stimulation of sustained growth, survival,migration and
drug resistance of cancer progenitor cells.
STRATEGIES FOR ELIMINATION
OF CSCs IN THE PROSTATE (I)
• Therapeutic strategies to repair or eliminate mutated stem
cells are in at their stages, and the dangers associated with
targeting stemness remain to be assessed.
• In determining the phenotypic differences between normal
and malignant stem cells in prostate, there was a signature
that could not only differentiate cancer from benign, but
also stem from TA cells.
• The cancer element is more tractable, and overlaps the
stem and TA compartiments: destruction of stem and TA
cells would provide a more lasting therapy than just
elimination of the more differentiated progeny cells as at
present.
STRATEGIES FOR ELIMINATION
OF CSCs IN THE PROSTATE (II)
• Thus, to target the stem cell compartment for elimination of the
CSCs will require new strategies and array systems that are quite
distinct form those used to derive antiproliferatives that are the
currently favored targets of the pharmaceutical industry.
First, arrays systemics for cancer drug development require the
availability of large numbers of cells, and are currently based on a
selected number of cell lines for most tumor types.
Second, because rapid proliferation is not necessary in the stem-cell
compartment, the assays required for elimination of the CSCs
cannot be measured by a slowing of growth rat or metabolism.
Third, there is also the likelihood that the CSCs have inherent
resistance mechanisms.