PARP Inhibitors for the treatment of MPNST

1
PARP Inhibitors for the treatment of MPNST
Sarcoma Research Laboratory University of Texas,
MD Anderson Cancer Center

• 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

2
Malignant Peripheral Nerve Sheath Tumor (MPNST)

• Accounts for 310 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)

3
MPNST treatment and outcome

• Surgical excision is the
• mainstay of treatment
• Radiation/chemotherapy ?
• High rate of local and systemic recurrence

Zou et al., 2009
4
There is a critical need for novel effective
therapies in MPNST
5
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

6
The goal of our studies was to determine the
effects of PARP inhibitors on MPNST in vitro
and in vivo
7
Experimental Models
Lopez et al., 2011
8
PARPi treatment reduces PARP activity
9
Decrease in cell proliferation with AZD2281
Control Cell lines 96 hour treatment
cell growth
AZD2281 (uM)
10
Decrease in cell proliferation with AZD2281
MPNST Cell Lines 96 hour treatment
cell growth
AZD2281 (uM)
11
AZD2281 treatment decreases colony forming ability
MPNST 724
AZD2281 (uM)
12
AZD2281 causes G2/M cell cycle arrest
MPNST 724 24 hour treatment
2.5uM AZD
10.0uM AZD
control
5.0uM AZD
G1
G2
G2
G2
G1
G1
G2
S
S
S
S
G1
G2/M 53.217
G2/M 22.794
G2/M 79.795
G2/M 66.366
13
AZD2281 induces apoptosis
MPNST 724 96 hour treatment
control
2.5uM AZD
5.0uM AZD
10.0uM AZD
8 total apoptosis
30 total apoptosis
35 total apoptosis
42 total apoptosis
14
Effect on tumor growth
MPNST Xenograft Subcutaneous Injection (16 mice)
Tumors grow to 5mm
Intraperitoneal injection
Treatment (8 mice) 50mg/kg/day AZD2281
Vehicle (8 mice) PBS10DMSO10HPCB
Sacrifice mice when vehicle group reaches
1500mm3, measure tumor volume and weight,
preserve tissue
15
AZD2281 abrogates tumor growth
MPNST 724
MPNST 724 MPNST
26T
p 0.0002

16
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?

17
Acknowledgements
18
(No Transcript)
19
PARP Function and Inhibition
20
PARP Activity Assay

-
Biotinylated NAD
Strepavidin HRP
21
Complex MPNST Karyotype
724
The chromosome in this cell line ranged from
47-91 , the modal chromosome being 58
22
DNA damage PCR array Results
Name Relative Fold Change to NSC Relative Fold Change to NSC Relative Fold Change to NSC
Upregulated 724 ST88 462
BRCA1 9.7( 3.2) 29.9( 8.7) 18.0( 6.1)
CCNO 10.3( 4.8) 43.5( 24.4) 161.6( 86.7)
EXO1 30.7( 5.2) 32.2( 5.8) 43.9( 10.9)
FEN1 7.8( 3.6) 13.1( 4.3) 12.6( 3.6)
LIG1 19.0( 6.8) 24.6( 5.5) 26.6( 9.9)
MSH2 5.4( 0.6) 5.3( 0.7) 20.4( 3.3)
NEIL3 10.9(5.7) 13.7(10.1) 20.3(17.5)
PARP1 6.6( 3.6) 12.1( 6.1) 12.6( 6.4)
POLD3 8.7( 2.8) 6.8( 2.7) 6.5( 2.1)
RAD51 11.0( 7.2) 8.5( 4.1) 15.6( 4.1)
RAD54L 29.7( 12.3) 30.4( 7.6) 38.4( 11.8)
RPA3 5.5( 0.3) 6.1( 0.5) 5.5( 0.1)
XRCC2 24.5( 5.5) 37.8( 6.41) 30.9( 3.4)