SRI Supplement to Reproductive Sciences - Volume 25 Number 1 - March 2018 - 91A

Scientific Abstracts

O-102
Co-Occurrence of Somatic Mutations in Tumor Suppressor ARID1A
and Estrogen Receptor Cofactor NRIP1 in Endometrial Cancer.
Zhigui Li†, Oloruntoba I Osagie, Gary L Goldberg, Gloria S Huang*.
Yale School of Medicine, New Haven, CT, United States.
INTRODUCTION: Mutations in the tumor suppressor ARID1A resulting
in loss of expression is a frequent event in endometrial cancer. Genetic
ablation of ARID1A in mice enhances the endometrial proliferative
response to estrogen (Kim et al, PLOS Genetics 2015). We hypothesize
that ARID1A cooperates with alterations in sex hormone receptors in
carcinogenesis of the endometrium.
METHODS: The primary study cohort was comprised of all the TCGA
uterine corpus endometrial carcinoma patients with tumor DNA sequence
and copy number alteration data, N=240 (TCGA, Nature 2013). Mutual
exclusivity and co-occurrence analysis was done using the cBioPortal
for Cancer Genomics (Cerami et al, Cancer Discovery 2012; Gao et al,
Sci Signal 2013) to analyze somatic genetic alterations in the following:
Baf chromatin remodeling complex member ARID1A; classical estrogen
receptors ESR1 and ESR2; obligate estrogen receptor cofactor NRIP1;
progesterone receptor PGR; and G-protein coupled estrogen receptor
GPER1. Results were expressed as Log Odds Ratio and P-value by
Fisher's Exact Test, where P<0.05 was deemed significant. Additional
mutual exclusivity and co-occurrence analysis was done in the pan-cancer
MSK-IMPACT cohort (MSKCC, Nat Med 2017). In this secondary cohort,
the analysis was limited to ARID1A, ESR1, and PGR since NRIP1, ESR2,
and GPER1 were not sequenced.
RESULTS: Among the 240 uterine endometrial cancer samples from
the TCGA cohort, the frequency of somatic genetic alterations was:
ARID1A, N=82 (34%), PGR, N=16 (7%), ESR1, N=14 (6%), NRIP1,
N=13 (5%), ESR2, N=4 (1.7%), and GPER1, N=4 (1.7%). Gene pairs with
significant co-occurrence were: ARID1A and NRIP1 (P=0.009, Log Odds
Ratio=1.557), ESR1 and PGR (P=0.009, Log Odds Ratio=1.965), ESR1
and NRIP1 (P=0.032, Log Odds Ratio=1.773), PGR and NRIP1 (P=0.046,
Log Odds Ratio=1.597). ARID1A alterations were predominantly
truncating mutations, while the majority of NRIP1 alterations were
missense mutations. In the pan-cancer MSK-IMPACT cohort (N=10,945),
significant co-occurring alterations were noted in the following gene
pairs: ARID1A and PGR (P<0.001, Log Odds Ratio=1.379), ARID1A
and ESR1 (P<0.001, Log Odds Ratio=0.807), ESR1 and PGR (P<0.001,
Log Odds Ratio=0.807).

91A

CONCLUSION: The significant co-occurrence of ARID1A and NRIP1
somatic alterations in endometrial cancer supports our hypothesis of
cooperativity between ARID1A and female sex hormone receptors in
carcinogenesis. This novel finding is further supported by the significant
co-occurrence of ARID1A with ESR1 and PGR alterations in a large
pan-cancer cohort.

O-103
Integrative Analysis of Multi-Omics Exosomal Data for Identifying
Multi-Markers for Susceptibility to Chemotherapy in Ovarian
Cancer. Mona Alharbi†,2 Andrew Lai,2 Dominic Guanzon,2 Shayna
Sharma,2 Carlos Palma,2 Felipe Zuñiga,3 Gregory E Rice,2 Lewis Perrin,1
John D Hooper,1 Carlos Salomon*.2 1Mater Research Institute-University
of Queensland, Brisbane, Australia; 2The University of Queensland,
Brisbane, Australia; 3University of Concepción, Concepción, Chile.
INTRODUCTION: Ovarian cancer usually has a poor prognosis because
it predominantly presents at advanced stages. New approaches are
required to develop more effective early detection strategies and real-time
treatment response monitoring. Exosomal content (proteins and miRNAs)
are often parent cell specific, thus providing insight or "fingerprint" of
the intracellular environment. Therefore, this study aimed to identify an
exosomal signature which can be used to determine a patients response
to the chemotherapy.
METHODS: A panel of ovarian cancer cell lines (SKOV-3, OVCA420, OVCA-429, TOV-II2D, OVTOKO, OV90, CAOV-3, HEY and
OVCAR-3) were used in this study. Cells were cultured under 8% O2
to mimic the physiological conditions. Cell migration, proliferation
and apoptosis (caspase3/7) in response to different concentrations of
carboplatin (0-1000 uM) were evaluated using a real-time monitoring
system (IncuCyte). The proteomic and miRNA profiles were determined
using SWATH mass spectrometry analysis and Next Generation
Sequencing (Illumina technology), respectively. Hierarchical clustering
and principal component analysis (PCA) was used for multi-omics
analyses. Finally, the set of biomarkers were validated in circulating
exosomes obtained from a small cohort of patients with recurrence.
RESULTS: Ovarian cancer cells with different origins and histotypes
present significant differences in their migration capacity, specifically
high migration SKOV-3, OVTOKO, -OVCA-420 and HEY; intermediate
migration TOV-2IID, OVCA-429 and OVACR-3 and low migration
CAOV-3 and OV90. Interestingly, the migration capacity of these cells
was associated with cell apoptosis in response to carboplatin, specifically
EC50 of 12.1 ± 2.6, 9.4 ± 2.2, 4.4 ± 1.5, 4.1 ± 1.6, 4.0 ± 1.9, 2.8 ± 0.9,
1.5 ± 0.6, 0.9 ± 0.2 and 0.7 ± 0.1 for HEY, SKOV-3, OVAC-429, OV90,
OVTOKO, OVCA-420, OVCAR-3, CAOV-3 and TOV-II2D, respectively.
In contrast, the proliferation of these cells inversely correlated (p<0.005)
with their migration and EC50. PCA was able to separate these ovarian
cancer cells into two distinct resistant and sensitive groups, based on
migration, proliferation, and response to carboplatin. Using SWATH
MS/MS and miRNA sequencing approach, we successfully identified 25
multi-markers in circulating exosomes to identify patients with recurrence
of ovarian cancer.
CONCLUSION: We suggest that exosomal cargo may be used as
prognostic biomarkers to monitor patients' response to treatments.

O-104
AXL Inhibition Improves Chemo Response in Gynecologic Serous
Cancers. Katherine Fuh, Jeanne Quinn, Meg Palisoul, Molly Greenwade,
Katina Massad, Lei Guo, Andrea Hagemann, Carolyn McCourt, Premal
Thaker, Matt Powell, Dave Mutch. Washington University, St. Louis,
MO, United States.
INTRODUCTION: Genetic inhibition of AXL decreases invasion,
migration, and metastasis in gynecologic serous cancers. We sought to
determine how therapeutic inhibition of AXL affects treatment response
in in vitro and in vivo models of ovarian and uterine serous cancers.
METHODS: Taxane and platinum resistant ovarian and uterine serous cell
lines were used for cell viability (XTT) assays. Western blotting was used
to detect protein expression. Selective small molecule inhibition of AXL
was achieved using BGB324. Single and combined therapy was assessed

Friday Orals

expression in these biologically aggressive (Type II) endometrial cancers,
and evaluate FRα as a targetable receptor for IMGN853 (Mirvetuximab
soravtansine).
METHODS: The expression of FRα was evaluated by
immunohistochemistry (IHC) and flow cytometry in 90 endometrioid clear
cell and USC samples. The in vitro cytotoxic activity and bystander effect
were studied in primary uterine cancer cell lines expressing differential
levels of FRα. In vivo antitumor efficacy of IMGN853 was evaluated in
xenograft/patient derived xenograft (PDX) models.
RESULTS: Semi-quantitative IHC analysis indicated that 41% of the USC
patients overexpress FRα. Further, overexpression of FRα (ie, 2+) was
detected via flow cytometry in 22% (2/9) of primary endometrioid/clear
cell and in 27% (3/11) of primary USC cell lines. Increased cytotoxicity
was seen with IMGN853 treatment compared to control in uterine
tumor cell lines (USC and endometrioid/clear cell) expressing 2+ FRα.
In contrast, tumor cell lines with low FRα showed no difference when
exposed to IMGN853 versus control. IMGN853 induced bystander killing
of FRα = 0 tumor cells. In an endometrioid/clear cell xenograft model
(END(K)265), harboring 2+ FRα, IMGN853 treatment showed complete
resolution of tumors (p=0.0005) (Figure 1). Treatment with IMGN853 in
USC PDX model (BIO(K)1), expressing 2+ FRα, induced 2-fold increase
in median survival (p=0.0006) (Figure 1)
*Figure(s) will be available online.
CONCLUSION: IMGN853 shows remarkable anti-tumor activity in
biologically aggressive FRα 2+ uterine cancers. This preclinical data
suggests that patients with chemotherapy resistant/recurrent endometrial
cancer overexpressing FRα may benefit from this treatment.

Reproductive Sciences Vol. 25, Supplement 1, March 2018

Table of Contents for the Digital Edition of SRI Supplement to Reproductive Sciences - Volume 25 Number 1 - March 2018