Post on 14-Dec-2015
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PARP Inhibitors for the treatment of MPNST
Christine Kivlin, Roman Belousov, Gonzalo Lopez, Quan-Sheng Zhu, Kai-Lieh Huang, Davis Ingram,
Keila E. Torres, Alexander J. Lazar, Raphael E. Pollock, Dina Lev
Sarcoma Research LaboratoryUniversity of Texas, MD Anderson Cancer Center
Malignant Peripheral Nerve Sheath Tumor (MPNST)
• Accounts for 3–10% of soft tissue sarcomas
• Up to 1,200 new cases in the U.S. per year
• High metastatic potential
• Neurofibromatosis type I (NF1)-related cases (50%) and sporadic (50%)
• Associated with a precursor lesion (NF1-related, deep neurofibromata)
MPNST treatment and outcome
• Surgical excision is the
mainstay of treatment
• Radiation/chemotherapy =?
• High rate of local and systemic recurrence
Zou et al., 2009
PARP inhibitors for the treatment of cancer
• PARPi have been used in clinical trials over the past few years for common cancers, role for sarcoma unknown
• Tumors with DNA repair defects are most highly sensitive
The goal of our studies was to determine the effects of
PARP inhibitors on MPNST in vitro and in vivo
PARPi treatment reduces PARP activity
MPNST 724
PARP inhibitor (10uM)
Rel
ativ
e P
AR
P A
ctiv
ity
AZD2281Olaparib
(AstraZeneca)
ABT888Veliparib
(Abbott Laboratories)
BSI201Iniparib
(Sanofi Aventis)
MPNST 26T
PARP inhibitor (10uM)
Rel
ativ
e P
AR
P A
ctiv
ity
Decrease in cell proliferation with AZD2281
AZD2281 (uM)
% c
ell g
row
thControl Cell lines96 hour treatment
Decrease in cell proliferation with AZD2281
MPNST Cell Lines96 hour treatment
NSC
724
26T
ST88
462
AZD2281 (uM)
% c
ell g
row
th
AZD2281 treatment decreases colony forming ability
AZD2281 (uM)
MPNST 724
control 5.0 10.0 0.6125 1.25 2.5
AZD2281 causes G2/M cell cycle arrest
control 2.5uM AZD 5.0uM AZD 10.0uM AZD
G2/M: 53.217% G2/M: 66.366% G2/M: 79.795%G2/M: 22.794%
MPNST 72424 hour treatment
G1
SG2
G1
G1
G1S S S
G2 G2 G2
AZD2281 induces apoptosis
control 2.5uM AZD 5.0uM AZD 10.0uM AZD
MPNST 72496 hour treatment
8% total apoptosis 30% total apoptosis 35% total apoptosis 42% total apoptosis
Effect on tumor growthMPNST Xenograft: Subcutaneous Injection (16 mice)
Tumors grow to 5mm
Treatment (8 mice)50mg/kg/day AZD2281
Vehicle (8 mice)PBS+10%DMSO+10%HPCB
Sacrifice mice when vehicle group reaches 1500mm3, measure tumor volume and weight, preserve tissue
Intraperitoneal injection
Conclusions• MPNST cells are relatively sensitive to
PARP inhibition in vitro– Decrease in cell proliferation– G2/ M cell cycle arrest– Enhanced apoptosis
• Anti-tumor effect of PARPi in vivo– Cytostatic effect on tumor proliferation– Role of PARPi in combination with
chemotherapy preclinical/clinical trials?
PARP Activity Assay
Histone- coated strip wells
AZD2281ABT888BSI 201
-Add PARPi of interest
-Add cell lysate
-Add PARP cocktail, incubate
NAD
Add TACS Sapphire
Add HCl
Read Absorbance at 450nm
Biotinylated NAD:
Strepavidin HRP:
+ -
The chromosome # in this cell line ranged from 47-91 , the modal chromosome # being 58
724
Complex MPNST Karyotype