2 research outputs found
Control of genomic stability by APC/C-Cdh1 and therapeutic implications
Full text linkTesis doctoral inédita, leída en Universidad Autónoma de Madrid, facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 11-11-2013The
E3-‐ubiquitin
ligase
APC/C-‐Cdh1
is
essential
for
embryonic
endoreduplication
but
its
relevance
in
the
mammalian
mitotic
cell
cycle
is
still
unclear.
We
show
here
that
genetic
ablation
of
Cdh1
in
the
developing
nervous
system
results
in
hypoplastic
brain,
abnormal
development
of
ependymal
cells
and
hydrocephalus.
These
defects
correlate
with
increased
levels
of
multiple
cell
cycle
regulators
and
increased
entry
into
S-‐phase
in
neural
progenitors,
resulting
in
replicative
stress.
However,
cell
division
is
prevented
in
the
absence
of
Cdh1
due
to
the
activation
the
DNA
damage
response,
induction
of
p53,
G2
arrest
and
apoptotic
death.
Concomitant
ablation
of
p53
rescues
apoptosis
but
not
replicative
stress,
resulting
in
premature
death
due
to
the
presence
of
damaged
neurons
throughout
the
adult
brain.
Interestingly,
partial
inhibition
of
cyclin-‐dependent
kinases
(Cdks)
rescues
the
replicative
stress
and
the
defective
proliferation
suggesting
that
Cdh1
loss
results
in
DNA-‐damage-‐like
response
due
to
Cdk
hyperactivation.
In
addition,
by
using
a
proteomic
approach
in
Cdh1-‐null
cells
and
mouse
tissues,
we
have
identified
the
kinesin
Eg5
and
topoisomerase
2α
as
APC/C-‐Cdh1
targets
involved
in
the
maintenance
of
genomic
stability.
The
high
levels
of
Eg5
in
Cdh1-‐null
cells
are
accompanied
by
partial
resistance
to
Eg5
inhibitors
such
as
monastrol.
In
contrast,
Cdh1-‐null
cells
display
a
dramatic
sensitivity
to
Top2α
poisons
currently
used
in
cancer
therapy
as
a
consequence
of
increased
levels
of
trapped
Top2α-‐DNA
complexes.
Treatment
of
human
cancer
cells
with
APC/C
inhibitors
results
in
increased
sensitivity
to
Top2α
poisons
revealing
a
new
synthetic
lethal
interaction
that
could
be
used
for
the
optimization
of
anticancer
treatments.
These
data
indicate
that
a)
Inactivation
of
Cdh1
in
vivo
results
in
replicative
stress,
cell
cycle
arrest
and
cell
death;
and
b)
APC/C
inhibition
may
have
therapeutic
use,
not
only
by
inhibiting
Cdc20
leading
to
mitotic
arrest,
but
also
by
altering
the
levels
of
Cdh1
substrates
(such
as
Eg5
and
Top2α).
Thus,
targeting
the
APC/C
may
result
in
differential
responses
(increased
resistance
or
susceptibility)
to
specific
therapeutic
agents.La
E3-‐ubiquitina
ligasa
APC/C-‐Cdh1
es
esencial
para
la
endoreduplicación
durante
el
desarrollo
embrionario,
pero
su
relevancia
en
el
ciclo
celular
mitótico
de
mamíferos
todavía
no
está
clara.
La
eliminación
genética
de
Cdh1
específicamente
en
el
sistema
nervioso
resulta
en
hipoplasia,
desarrollo
anormal
de
las
células
ependimarias
e
hidrocefalia.
Estos
defectos
correlacionan
con
un
incremento
en
niveles
de
reguladores
del
ciclo
celular
y
en
entrada
en
fase
S
en
los
progenitores
neurales,
que
da
lugar
a
estrés
replicativo.
En
ausencia
de
Cdh1
estas
células
progenitoras
no
progresan
en
el
ciclo
debido
a
la
activación
de
la
respuesta
a
daño
en
el
DNA,
la
inducción
de
p53,
la
parada
en
la
fase
G2
y
la
muerte
celular
programada
(apoptosis).
La
eliminación
de
p53
previene
la
apoptosis
de
las
células
deficientes
para
Cdh1,
pero
no
el
estrés
replicativo.
Sin
embargo,
la
inhibición
parcial
de
la
actividad
de
quinasas
dependientes
de
ciclinas
(Cdks)
rescata
el
estrés
replicativo
y
los
problemas
en
proliferación,
lo
que
sugiere
que
la
acumulación
de
daño
en
el
DNA
en
ausencia
de
Cdh1
se
debe
a
la
hiperactivación
de
las
Cdks.
Además,
mediante
técnicas
proteómicas
en
células
y
tejidos
deficientes
para
Cdh1,
hemos
identificado
a
la
kinesina
Eg5
y
la
topoisomerasa
2α
como
nuevos
sustratos
de
APC/C-‐Cdh1
implicados
en
el
mantenimiento
de
la
estabilidad
genómica.
La
acumulación
de
Eg5
en
células
donde
se
ha
eliminado
Cdh1
provoca
una
resistencia
parcial
al
inhibidor
de
Eg5
monastrol.
Por
otro
lado,
las
células
deficientes
para
Cdh1
son
especialmente
sensibles
al
inhibidor
de
topoisomerasa
etopósido,
actualmente
utilizado
en
tratamientos
antitumorales.
De
hecho,
el
tratamiento
de
líneas
tumorales
humanas
con
un
inhibidor
de
APC/C
incrementa
la
sensibilidad
a
inhibidores
de
topoisomerasa
2.
Estos
datos
muestran
que:
a)
La
inactivación
de
Cdh1
in
vivo
provoca
estrés
replicativo,
parada
del
ciclo
y
muerte
celular;
and
b)
La
inhibición
de
APC/C
puede
tener
aplicaciones
terapéuticas,
no
sólo
a
través
de
la
inducción
de
parada
en
mitosis
por
bloqueo
de
la
actividad
de
cdc20,
sino
también
mediante
el
aumento
de
niveles
de
sustratos
de
Cdh1
(tales
como
Eg5
o
Top2α)
que
modulan
la
respuesta
a
distintos
tratamientos
contra
el
cancer
A synthetic lethal interaction between APC/C and topoisomerase poisons uncovered by proteomic screens.
No full textThe Anaphase-promoting complex/cyclosome (APC/C) cofactor Cdh1 modulates cell proliferation by targeting multiple cell-cycle regulators for ubiquitin-dependent degradation. Lack of Cdh1 results in structural and numerical chromosome aberrations, a hallmark of genomic instability. By using a proteomic approach in Cdh1-null cells and mouse tissues, we have identified kinesin Eg5 and topoisomerase 2α as Cdh1 targets involved in the maintenance of genomic stability. These proteins are ubiquitinated and degraded through specific KEN and D boxes in a Cdh1-dependent manner. Whereas Cdh1-null cells display partial resistance to Eg5 inhibitors such as monastrol, lack of Cdh1 results in a dramatic sensitivity to Top2α poisons as a consequence of increased levels of trapped Top2α-DNA complexes. Chemical inhibition of the APC/C in cancer cells results in increased sensitivity to Top2α poisons. This work identifies in vivo targets of the mammalian APC/C-Cdh1 complex and reveals synthetic lethal interactions of relevance in anticancer treatments.We thank Angeles Almeida, Thomas U. Mayer, William T. Beck, Anthony A. Hyman, Jan-Michael Peters, Eusebio Manchado, and Scott Lowe for reagents. M. E., A.J.L.-C., and M.A.-F. were supported by the Spanish Ministry of Education, Culture and Sports, the AECC Scientific Foundation, and the EU-PEOPLE programme, respectively. Work in the O.F.-C. laboratory was supported by grants from the Spanish Ministry of Economy and Competitiveness (MINECO; SAF2011-23753), the Association for International Cancer Research (120229), the Howard Hughes Medical Institute, and the European Research Council (ERC-210520). Work in the H.Y. laboratory was funded by grants from Marie Curie Cancer Care and Cancer Research UK. Work in M.M.'s laboratory was funded by grants from the Foundation Ramon Areces, MINECO (SAF2012-38215), the OncoCycle Programme (S2010/BMD-2470) from the Comunidad de Madrid, and the European Union Seventh Framework Programme (MitoSys project; HEALTH-F5-2010-241548).S
