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Abstract 268
ODM-207, a novel BET-bromodomain inhibitor as a therapeutic approach
for the treatment of patients with castration resistant prostate cancer
Mari
1
Björkman ,
1
Mattila ,
1
Riikonen ,
2
Abbineni ,
2
Jaleel ,
2
Marappan , Tarja
Elina
Reetta
Chandrasekhar
Mahaboobi
Sivapriya
1
2
2
1
1
Daniel Nicorici , Susanta Samajdar , Murali Ramachandra Pekka Kallio , Anu Moilanen
1
Ikonen ,
1Orion Corporation Orion Pharma, Espoo, Finland, 2Aurigene Discovery Technologies Limited, Bangalore, India
Background
Results
During normal development, the androgen receptor (AR) regulates genes
that are essential for the differentiation of the prostate. However, in
prostate cancer (PCa), AR-regulated gene transcription is re-directed to
drive the malignant phenotype. Also castration resistant prostate cancer
(CRPC) is dependent on AR and is characterized by persistent activation of
AR signaling by residual tissue androgens. In fact, activation of AR signaling
has been shown to be crucial for prostate cancer growth at all stages of
the disease and several molecular mechanisms have been proposed to
explain the addiction to AR including emergence of AR overexpression, AR
ligand binding domain (LBD) mutations and splicing variants lacking the
LBD. Unfortunately, despite recent advances in treatment of CRPC, nearly
all patients treated with current hormonal therapies eventually will
relapse.
1. ODM-207 is a novel, potent, and structurally distinct
Herein, we performed RNA-sequencing studies and gene set enrichment
analysis of ODM-207 treated VCaP cells to study the pathways regulated
by ODM-207. Gene set enrichment analysis indicates significant changes in
expression of genes involved in e.g. MYC and AR gene signatures. Indeed,
in cellular studies with AR-positive prostate cancer cell lines as well as
22Rv1 xenograft model, ODM-207 showed potent down-regulation of
Myc, an important oncogenic regulator of cell proliferation and
tumorigenesis.
xenograft
a) Effect of ODM-207 on tumor volumes
inhibitor of BET proteins
a) Biochemical potency of b) Antiproliferative effects
of ODM-207 in prostate
ODM-207
cancer cell lines
Bromodomain
BRD4 full length
IC50
(nM)
89
***
b) Effect of ODM-207 on tumor weights
2. ODM-207 regulated pathways and genes in prostate cancer
cell lines
a) Differentially expressed genes in VCaP cells between ODM207 and DMSO treatment groups
2h
663
617
1031
1000
V e h ic le
O D M -2 0 7 3 0 m g / k g q d
500
***
E n z a lu t a m id e 2 0 m g / k g q d
0
c) ODM-207 inhibits Myc in in vivo efficacy study
6h
2453
530
2423
3277
d) ODM-207 downregulates Myc in prostate cancer cell
lines
ODM-207
24h
Methods
3. ODM-207 inhibits tumor growth in AR-V7 expressing 22Rv1
T u m o r w e ig h t / m g
Herein, we show that ODM-207, an inhibitor of tandem bromodomain
(BD) containing family of transcriptional regulators known as the BET
(bromodomain and extraterminal) proteins antagonizes the interaction
between the Brd4 and acetylated histone peptides. In cellular studies with
AR-positive prostate cancer cell lines, ODM-207 possessed potent growth
inhibitory activity. ODM-207 also displayed potent antiproliferative activity
in a VCaP model resistant to second generation anti-androgen
enzalutamide and inhibited the expression of the AR splice variant AR-V7.
In 22Rv1 prostate cancer xenograft, oral administration of ODM-207 was
efficacious in suppressing tumor growth at well tolerated doses.
c) Fold changes of selected genes in AR, MYC, p53, apoptosis,
DNA repair, G2M checkpoint and E2F pathways
0
30
300
3000
nM
22Rv1
b) Pathways regulated by ODM-207 in VCaP cells
VCaP
Biochemical activity: Binding of ODM-207 to BRD4 full length recombinant protein was tested by measuring
the displacement of bromodomain/acetylated peptide interaction using biotin conjugated Acetyl-Histone H4
[Lys5,8,12,16] peptide and the TR-FRET assay.
Conclusions
LNCaP
ODM-207 regulated pathways in VCaP cell line
Cells lines: VCaP, LNCaP and
22Rv1 cell lines were purchased from ATCC and maintained in the condition
recommended by the provider. VCaP enzalutamide resistant (VCaP enza res.) cell line was developed by passaging
VCaP cells in the presence of increasing concentrations of enzalutamide over 18 months. Cell line is maintained in
growth media supplemented with 7.6 µM enzalutamide.
 ODM-207 is a novel and structurally distinct BET protein
inhibitor
e) ODM-207 downregulates AR-V7 in VCaP and
enzalutamide resistant VCaP cell lines
Cell viability assays: VCaP, VCaP enzalutamide resistant , LNCaP and
22Rv1 cell lines were plated on 96-well
plates and treated with ODM-207 for 4 days. Growth inhibitory effect of ODM-207 in cell lines was measured using
WST-1 Cell Proliferation Assay (Roche).
ODM-207
Gene expression analyses: VCaP cells were treated with vehicle
control or 1 µM ODM-207 in triplicate for
2, 6 and 24h. Differentially expressed genes and gene sets enrichment were analyzed by RNA-seq 15M
reads/sample (Illumina HiSeq).
0
Immunoblotting:
AR-V7
22Rv1 xenograft: Tumors were established by subcutaneous injection of 22Rv1 cells into male nude mice.
GAPDH
After initial tumor growth, when the average tumor volume reached 127 mm3, oral treatment with ODM-207 30
mg/kg qd, enzalutamide 20 mg/kg qd or vehicle was initiated and continued for 27 days. Tumor volume was
measured with a caliper during the course of the study. Animals were sacrificed at 4h after last dosing. Tumor
weights were determined, and Myc protein expression levels of the tumors were measured using Milliplex MAP
Myc Signaling Kit (Millipore Cat#48-602MAG). FI/prot = fluorescence intensity / amount of protein. ***, p<0,0001
AR-V7
Cells were treated for 24h with ODM-207 and cell samples were immunoblotted with ARV7 (Abcam, ab198394), Myc (Covance, MMS-150P) and GAPDH (Cell Signaling, 2118S) antibodies.
Poster presented at EORTC-NCI-AACR Symposium 2016
Munich, Germany, 29 Nov-2 Dec 2016
0
30
30
GAPDH
These studies were sponsored by Orion Corporation Orion Pharma
VCaP
300 300 3000 3000 nM
VCaP enza
res.
 ODM-207 inhibits proliferation of androgen receptor dependent
prostate cancer cell lines including enzalutamide-resistant
models
 Causes suppression of AR target genes, Myc signaling
and DNA repair pathway and induction of p53 pathway
as well as apoptosis
 Induces a dose-dependent reduction in Myc and AR-V7
splice variant protein levels
 In vivo, oral administration of ODM-207 potently inhibits tumor
growth and Myc expression in 22Rv1 prostate cancer xenograft
model
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