Targeting ZAP70:

1
Targeting ZAP-70 A New Treatment Strategy in
Chronic Lymphocytic Leukemia Januario E.
Castro, M.D. Assistant Professor - Division of
BMT Rebecca and John Moores Cancer Center UCSD
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• B cell activation in normal and CLL cells
• Differential activation patterns of NF?B in CLL
  cells
• Biology of ZAP-70 and why it is a High Risk
  prognostic factor in CLL
• Heat Shock Protein-90 (Hsp90) protein complex
  its function in CLL
• How to translate our results from the laboratory
  to the patients

• Overview

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Normal Activation in B cells
BCR
Syk
NF?B
Nucleus
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ZAP-70 Mediated Activation Model in CLL
BCR
ZAP-70
Syk
NF?B
Nucleus
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Differential NF?B Activation in CLL
I?B-? Degradation
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Differential NF?B Activation in CLL
MEDIA Anti-µ MEDIA
Anti-µ
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CLL
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ZAP-70
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ZAP-70
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ZAP-70 Expression and Disease Progression in CLL
Rassenti et al. NEJM 2004, 351893
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ZAP-70 Function is Supported by Hsp90
BCR
Hop
ATP
ZAP-70
Syk
p23
NF?B
Nucleus
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Hsp90 Chaperon Complex Cycle
Kamal,A., et al. Trends Mol Med. 2004
Jun10(6)283-90. Kamal,A., et al. Nature. 2003
(425) 407
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Cells Active Hsp90 Expression in CLL
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ZAP-70 is a Novel Hsp90 Client Protein
BOUND
UNBOUND
CLL ZAP-70
CLL ZAP-70 -
T cells
B cells
T cells
B cells
CLL ZAP-70
CLL ZAP-70 -
MCF7
MCF7
IP
WB
No Ab
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ZAP-70 Function is Supported by Hsp90
BCR
Hop
ATP
GM
ZAP-70
Syk
p23
NF?B
Nucleus
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ZAP-70 Function is Supported by Hsp90
17-AAG 17-DMAG
BCR
ZAP-70
Syk
NF?B
Nucleus
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ZAP-70 Function is Supported by Hsp90
17-AAG 17-DMAG
BCR
Syk
NF?B
Nucleus
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Hsp90 Inhibition Induces Apoptosis in CLL cells
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Hsp90 Inhibition Induces Apoptosis in CLL cells
d.
Apoptosis
17-AAG (nM)
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Hsp90 Inhibition Induces ZAP-70 Degradation in
CLL cells
17-AAG (nM)
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Hsp90 Inhibition Induces ZAP-70 Degradation in
CLL cells
WB
Time (hrs)
0 24 72 24
72
ZAP-70
Hsp70
PARP-1
?-Actin
- - -
17-AAG
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CLL Clinical Trials using Hsp90 Inhibitors
17-AAG
17-DMAG
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Our Patients Thomas J. Kipps, M.D., Ph.D. Laura
Rassenti, Ph.D. CRC Staff Januario E. Castro,
M.D. Carlos E. Prada, M.D. Jan Bole,
R.N. Undergrad Students Olivier Loria Jorieth
Jose Daniel Contreras