Cell Reports,
Год журнала:
2023,
Номер
42(7), С. 112792 - 112792
Опубликована: Июль 1, 2023
The
ATR
kinase
safeguards
genomic
integrity
during
S
phase,
but
how
protects
DNA
replication
forks
remains
incompletely
understood.
Here,
we
combine
four
distinct
assays
to
analyze
functions
at
ongoing
and
newly
assembled
upon
inhibition
by
hydroxyurea.
At
forks,
inhibitor
(ATRi)
increases
MRE11-
EXO1-mediated
nascent
degradation
from
PrimPol-generated,
single-stranded
(ssDNA)
gaps.
ATRi
also
exposes
template
ssDNA
through
fork
uncoupling
degradation.
Electron
microscopy
reveals
that
reduces
reversed
increasing
gap-dependent
new
triggers
CtIP-initiated
EXO1,
exposing
ssDNA.
Upon
PARP
inhibition,
preferentially
exacerbates
in
BRCA1/2-deficient
cells
disrupts
the
restored
gap
protection
BRCA1-deficient,
PARP-inhibitor-resistant
cells.
Thus,
mechanisms,
providing
an
extended
view
of
ATR's
stabilizing
forks.
Genes & Development,
Год журнала:
2022,
Номер
36(5-6), С. 278 - 293
Опубликована: Март 1, 2022
DNA
repair
and
damage
signaling
pathways
are
critical
for
the
maintenance
of
genomic
stability.
Defects
contribute
to
tumorigenesis,
but
also
render
cancer
cells
vulnerable
reliant
on
remaining
activities.
Here,
we
review
major
classes
defects
in
cancer,
instability
that
they
give
rise
to,
therapeutic
strategies
exploit
resulting
vulnerabilities.
Furthermore,
discuss
impacts
both
targeted
therapy
immunotherapy,
highlight
emerging
principles
targeting
therapy.
Nature Structural & Molecular Biology,
Год журнала:
2022,
Номер
29(4), С. 329 - 338
Опубликована: Март 24, 2022
Abstract
Poly(ADP-ribose)
polymerase
1
(PARP1)
is
implicated
in
the
detection
and
processing
of
unligated
Okazaki
fragments
other
DNA
replication
intermediates,
highlighting
such
structures
as
potential
sources
genome
breakage
induced
by
PARP
inhibition.
Here,
we
show
that
PARP1
activity
greatly
elevated
chicken
human
S
phase
cells
which
FEN1
nuclease
genetically
deleted
highest
behind
forks.
inhibitor
reduces
integrity
nascent
strands
both
wild-type
during
replication,
does
so
−
/
to
an
even
greater
extent
can
be
detected
postreplicative
single-strand
nicks
or
gaps.
Collectively,
these
data
inhibitors
impede
maturation
implicate
strand
discontinuities
cytotoxicity
compounds.
Abstract
DNA
damage
tolerance
and
mutagenesis
are
hallmarks
enabling
characteristics
of
neoplastic
cells
that
drive
tumorigenesis
allow
cancer
to
resist
therapy.
The
‘Y-family’
trans-lesion
synthesis
(TLS)
polymerases
enable
replicate
damaged
genomes,
thereby
conferring
tolerance.
Moreover,
Y-family
inherently
error-prone
cause
mutations.
Therefore,
TLS
potential
mediators
important
tumorigenic
phenotypes.
skin
cancer-propensity
syndrome
xeroderma
pigmentosum-variant
(XPV)
results
from
defects
in
the
Polymerase
Pol
eta
(Polη)
compensatory
deployment
alternative
inappropriate
polymerases.
However,
extent
which
dysregulated
contributes
underlying
etiology
other
human
cancers
is
unclear.
Here
we
consider
broad
impact
on
We
survey
ways
pathologically
altered
cancer.
summarize
evidence
shape
review
studies
implicating
as
a
driver
carcinogenesis.
Because
many
treatment
regimens
comprise
DNA-damaging
agents,
pharmacological
inhibition
an
attractive
strategy
for
sensitizing
tumors
genotoxic
therapies.
discuss
tractability
pathway
recent
progress
development
inhibitors
therapeutic
purposes.
Mutation
signatures
associated
with
apolipoprotein
B
mRNA
editing
catalytic
polypeptide-like
3A/B
(APOBEC3A/B)
cytidine
deaminases
are
prevalent
across
cancers,
implying
their
roles
as
mutagenic
drivers
during
tumorigenesis
and
tumor
evolution.
APOBEC3A
(A3A)
expression
induces
DNA
replication
stress
increases
the
cellular
dependency
on
ataxia
telangiectasia
Rad3-related
(ATR)
kinase
for
survival.
Nonetheless,
how
A3A
remains
unclear.
We
show
that
without
slowing
forks.
find
single-stranded
(ssDNA)
gaps
through
PrimPol-mediated
repriming.
A3A-induced
ssDNA
repaired
by
multiple
pathways
involving
ATR,
RAD51,
translesion
synthesis.
Both
ATR
inhibition
trapping
of
poly(ADP-ribose)
polymerase
(PARP)
PARP
inhibitor
impair
repair
gaps,
preferentially
killing
A3A-expressing
cells.
When
used
in
combination,
inhibitors
selectively
kill
cells
synergistically
a
manner
dependent
PrimPol-generated
gaps.
Thus,
arises
from
which
confer
therapeutic
vulnerability
to
gap-targeted
inhibitors.
Molecular Cell,
Год журнала:
2022,
Номер
82(22), С. 4218 - 4231.e8
Опубликована: Ноя. 1, 2022
POLθ
promotes
repair
of
DNA
double-strand
breaks
(DSBs)
resulting
from
collapsed
forks
in
homologous
recombination
(HR)
defective
tumors.
Inactivation
results
synthetic
lethality
with
the
loss
HR
genes
BRCA1/2,
which
induces
under-replicated
accumulation.
However,
it
is
unclear
whether
POLθ-dependent
replication
prevents
HR-deficiency-associated
lethality.
Here,
we
isolated
Xenopus
laevis
and
showed
that
processes
stalled
Okazaki
fragments,
directly
visualized
by
electron
microscopy,
thereby
suppressing
ssDNA
gaps
accumulating
on
lagging
strands
absence
RAD51
preventing
fork
reversal.
Inhibition
polymerase
activity
leaves
unprotected,
enabling
their
cleavage
MRE11-NBS1-CtIP
endonuclease,
produces
broken
asymmetric
single-ended
DSBs,
hampering
BRCA2-defective
cell
survival.
These
reveal
a
genome
protection
function
rupture
highlight
possible
resistance
mechanisms
to
inhibitors.
Cell Reports,
Год журнала:
2022,
Номер
41(9), С. 111716 - 111716
Опубликована: Ноя. 1, 2022
Polymerase
theta
(POLθ)
is
an
error-prone
DNA
polymerase
whose
loss
synthetically
lethal
in
cancer
cells
bearing
breast
susceptibility
proteins
1
and
2
(BRCA1/2)
mutations.
To
investigate
the
basis
of
this
genetic
interaction,
we
utilized
a
small-molecule
inhibitor
targeting
POLθ
domain.
We
found
that
processes
single-stranded
(ssDNA)
gaps
emerge
absence
BRCA1,
thus
promoting
unperturbed
replication
fork
progression
survival
BRCA1
mutant
cells.
A
genome-scale
CRISPR-Cas9
knockout
screen
uncovered
suppressors
functional
interaction
between
including
NBN,
component
MRN
complex,
cell-cycle
regulators
such
as
CDK6.
While
complex
nucleolytically
ssDNA
gaps,
CDK6
promotes
progression,
thereby
exacerbating
stress,
feature
BRCA1-deficient
lack
activity.
Thus,
gap
formation,
modulated
by
activity,
underlies
synthetic
lethality
important
insight
for
clinical
trials
with
inhibitors.