Changes in blood-brain barrier permeability to docetaxel in the presence of

Changes in blood-brain
barrier permeability to
docetaxel in the presence of
cancer influences cognitive
f
function
i
off mice
i
J
Joanna
Fardell, JJi Zhang,
g Raquel
q De
Souza, Ian Johnston, Janette
Vardy, Micheline Piquette-Miller
Chemotherapy & Cognition
What is known
•F
For a subset
b off survivors
i
chemotherapy
h
h
iis
associated with cognitive impairment
▫ Subtle impairment
▫ Affects a range of cognitive domains:
Visual and verbal memory
Processing speed and executive function Attention and concentration
Chemotherapy
py & cognition
g
animal studies:
What has been done so far?
• Previous animal studies have shown:
▫ Methotrexate
▫ 5-fluorouracil
▫ Doxorubicin/adriamycin
▫ Cyclophosphomide
Cognitive
g
impairment in
healthy
y animals
▫ Cytosine arabinoside
•Other chemotherapeutics??
•AND –what about the role of cancer??
Aims
• To examine the role of cancer in cognitive
decline associated with docetaxel (DTX)
chemotherapy
▫ Using a murine model of ovarian cancer (ID8
cancer cells)
• Secondary aims:
▫ Examine the role of ABC transporters (Pgp and
mrp7) in brain exposure to DTX
DTX and ABC transporters
• DTX is a substrate for ABC transporters
=P
P-glycoprotein
glycoprotein (Pgp)
(known as mdr1 in humans and mdr1a and mdr1b in mice)
= Mrp7
p7
• Transporters located in blood-brain barrier
▫ Actively
A ti l transports
t
t DTX outt off th
the cell
ll
▫ Has a role in multidrug resistance
Experimental design
Female
C57BL/6 mice
(N=40)
Day -14
ID8
inoculation
(vs healthy)
2x2
design:
Day 1
Plasma & brain
collection
(N=8)
Day 0
D
DTX (8mg/kg)
(vs control)
Days 2-6
Cognitive
testing (N=32)
ID8
healthy
DTX
ID8+DTX DTX
Control
ID8
Control
Day 7
Plasma & brain
collection
DTX concentrations (24h)
(using HPLC)
Brain
12
Br
rain DT
TX conce
entratio
on
(ng/g)
Pllasma D
DTX conc
centratiion
(ug/ml)
Plasma
10
8
6
4
2
0
Healthy +
DTX
ID8 + DTX
12
*
10
8
6
4
2
0
Healthy +
DTX
ID8 + DTX
Cognitive Test 1:
Novel object
j
recognition
g
(NOR)
( O )
▫ Object
j
recognition
g
memory
▫ Familiarityy
80 min
80 min
Sample Trial = 2 identical objects
Test Trial = 1 object familiar (from sample) & 1 novel (new) object
Results 2:
Cancer & DTX affect object recognition
ce (%)
Novell object prefenc
p
100
90
80
70
60
50
40
30
3
20
10
0
Control
Main effect of ID8:
F(1,29)=13.134 p<.05
ID8
ID8 + DTX
Interaction between ID8 + DTX:
F(1,29)=4.701 p<.05
DTX
Cognitive Test 2:
Morris water maze (MWM)
(
)
▫ Assesses spatial reference memory
▫ Requires
R
i
working
ki memory and
d retention/recall
i /
ll
Training trials
Platform fixed location
Random start position
Test trials = no platform, 1min free swim
Results 3:
Non-significant
No
s g ca t effects
e ects o
on spat
spatial
al memory
e oy
Latency tto cross
L
s platfor
rm (s)
60
50
40
Control
ID8
ID8+DTX
DTX
30
20
10
0
Train 1
Train 2
Test
Changes in gene expression (7days)
Gene ex
xpressio
on chan
nges
300%
3
250%
200%
*
150%
*
(using PCR)
Control
ID8
ID8 + DTX
DTX
*
100%
50%
0%
mrp7
mdr1a
Genes of interest
mdr1b
Limitations & thoughts
• Testing conducted shortly after treatment
▫ At this time DTX treatment is effective at killing
ID8 cancer cells –may
may explain interaction effect?
• No clear effect of DTX on MWM performance
▫ No delayed testing?
• Where to now?
▫ Inflammation?
Conclusions
• Cancer itself is associated with poor cognition
• DTX is associated with poor cognition
• The presence of cancer downregulates the
e pression of Pgp genes
expression
genes; This is associated with
ith
▫ Greater brain exposure to DTX
▫ Worse cognitive outcomes
•N
Nott all
ll d
domains
i off cognition
iti are iimpaired
i dd
due tto
cancer, chemotherapy or both
▫ But:
B t ti
timing
i off cognitive
iti ttestt
Thank you
• Prof Micheline PiquetteMiller
ill ((U off T))
• A/Prof Janette Vardy
• Dr Ian Johnston
• Raquell De Souza
• Ji Zhang
• Cancer
C
Institute
i
NSW
S
(RSA funding)
• Campbell Perry
International Travel
Scholarship
(School of Psychology, USyd)
• Canadian Cancer Society
Joanna Fardell
School of Psychology,
University of Sydney
[email protected]
Micheline Piquette-Miller
Leslie Dan Faculty of
Pharmacy, University of Toronto
[email protected]