Transcript differentiation therapy of apl

DIFFERENTIATION THERAPY
OF APL
. Retinoic acid and arsenic trioxide
. Differentiation into granulocytes
. Best prognosis among myeloid leukemias
(Cure rates: 30% in 1988, 70% 2003, 100%
very soon )
. First example of differentiation therapy
Huang, Blood 1988, Chen Blood 1996
THE t(15;17) TRANSLOCATION
. Specific for APL
. Rearranges the RARa gene into a PML/RARa fusion
. PML/RARa expression in transgenic mice suffice to
induce APL
. Rare variant translocations, all involving RARa
. First example of oncogene-targeted therapy
de Thé Nature 1990, de Thé Cell 1991
Combining RA/As in the mouse
• Transgenic mice develop APL
• RA-induced differentiation to granulocytes
• Demonstrates Arsenic trigger differentiation
in vivo (apoptosis ex vivo, no differentiation)
• RA/As synergy for disease regression (model
and cell line studies had predicted antagonism)
Survival
Treatment
RA/AS
5
PCR4
3
2
RA
1
AS
40
80
120
160
200
240
280
Days
Lallemand JEM 1999
APL PATIENTS ?
No relapse un dual-treated patients,
Arsenic better than RA!
ATRA + As2 O3 (n= 23)
60/61 CR
1.0
As2 O3 (n= 18)
.9
Disease free survival
.8
ATRA (n= 19)
.7
.6
.5
.4
.3
.2
.1
0
4
8
12
16
20
24
28
32
Time of follow up (months)
Chen PNAS 2004
PML/RARA-SPECIFIC REPORTERS
Fold induction
by RA
APL: RARA, PML/RARA
Non-APL: RARA
50
40
30
20
10
1
1
2
3
4
5
6
8
10 12
DR
16
0
8
IR ER
DR1-16
AGGTCA
IR0
ER3-8
Kamashev JEM 2004
• Major gain of function,
PML/RARA controls genes not regulated
by RA in non-APL cells
• PML/RARA-specific reporters:
test the real effects of RA exclusively
on the fusion in APL cells
cAMP/RA CROSS-TALKS
• Well-known for APL & F9 differentiation, but never
demonstrated for transcriptional activation by
RARA and PML/RARA
50
Fold
induction
40
30
20
10
1
RA, 10nM
cAMP
DR5
DR8
DR10
CONCLUSIONS (cAMP)
• cAMP functionally targets PML/RARA
Enhances differentiation by RA and As
Enhances RA activation of PML/RARAspecific reporters genes
• Reverts RA-resistance ex vivo and in vivo
• Clinically relevant: Theophyline first line
drug?
MYELOPROLIFERATION IN
PML/RARA-K160R TG MICE
7
6
5
nls-PML/RARAK160R
4
3
2
1
0
0
5
10
15
20
25
Months
SPLENOMEGALY
IRRADIATED
APL
UNIRRADIATED
GRAFT 1
But no progression
towards APL
GRAFT 2
n°4
n°16
(4/4)
n°17
SPLENOMEGALY
APL
PML/RARA
7/8 LINES
6/8 LINES
PML/RARA
K160R
10/10 LINES
0/10 LINES
(4/4)
n°23
(3/3)
n°26
(9/9)
GRAFT 2
GRAFT 1
n°14
n°22
(1/4)
n°24
(1/4)
n°27
(1/5)
n°30
(1/5)
0
5
10
15
20
25
30
35
40
Months
CONCLUSIONS (K160)
• PML/RARA homodimers do not suffice to
induce a differentiation block and do not
trigger APL
• PML sumolation critical to differentiation
block and immortalisation, most likely
through Daxx-triggered repression
• Could explains why PML is the common fusion
partner in APL
A sad note to finish
• Despite the absence of any basic or clinical
research and the low manufacturing costs,
Arsenic sells it for over 100 000 E for a
complete treatment
• Most countries, including France, cannot afford
it for first line patients, despite its obvious
superiority
• We may have failed just when we thought we
had succeeded...
CREDITS
CNRS 9051, Hôpital St. Louis, Paris
Jun ZHU, Jun ZHOU, Florence RIAUCOUX, Laurent PERES,
Nicole HONORE, Marie-Claude GUILLEMIN, Valérie LALLEMAND,
Hassane SOIHILI, Dmitrii KAMASHEV, Dominique VITOUX
Hôpital St. Louis, Paris
Emmanuel RAFFOUX, Hervé DOMBRET, Marie-Thérèse DANIEL,
Michel LANOTTE , Laurent DEGOS
USCF:
Scott KOGAN, Mike BISHOP
Pôle Franco-Chinois de Shanghai:
Zhu CHEN