289O - Molecular characterization of a panel of ovarian clear cell carcinoma (OCCC) cell lines (289O)

Date 18 November 2017
Event ESMO Asia 2017 Congress
Session Gynaecological cancers
Topics Ovarian Cancer
Basic Science
Gynaecologic Malignancies
Translational Research
Presenter Ruby Huang
Citation Annals of Oncology (2017) 28 (suppl_10): x86-x93. 10.1093/annonc/mdx663
Authors R. Huang1, J. Ye2, K.T. Kuay2, T.Z. Tan2, V. Heong3, D.S. Tan3
  • 1Gynaecologic Oncology, National University Cancer Institute, Singapore, 119228 - Singapore/SG
  • 2Cancer Science Institute Of Singapore, National University of Singapore, 117599 - Singapore/SG
  • 3Haematology-oncology, National University Cancer Institute Singapore, 119074 - Singapore/SG

Abstract

Background

OCCC is common in Asia and has been shown to be associated chemoresistance to standard therapy. With limited pre-clinical models available for drug screening and biomarker discovery, detailed characterization of existing OCCC cell lines is crucial to enhance our understanding of this disease.

Methods

6 OCCC cell lines (JHOC9, TAYA, RMG2, KOC7C, OVTOKO, RMG5) were profiled and authenticated using short tandem repeat (STR) profiling. DNA extracted were used for next generation sequencing (NGS) using ACT Genomics ACTOnco and ACTBRCATM. Mutations were identified using Torrent Variant Caller. Only nonsynonymous mutations with coverage ≥ 25, variant frequency ≥ 5%, and not found in common variant database were retained for analysis. Extracted RNA was used for gene expression microarray profiling using Affymetrix U133A2. Epithelial ovarian cancer gene expression molecular subtypes (GEMS) and epithelial-mesenchymal transition (EMT) scores were determined from microarray analysis.

Results

3 OCCC lines (JHOC9, TAYA, and RMG2) were found to be “Epithelial” displaying low EMT scores (-0.71, -0.69, -0.53) while 3 other OCCC lines (KOC7C, OVTOKO, RMG5) were “Mesenchymal” with high EMT scores (0.23, 0.28, 0.4). All the Epithelial lines were characterized as Epi-A, while two Mesenchymal lines (KOC7C and RMG5) were characterized as Stem-A, and OVTOKO was Mes when characterized via GEMS. ARID1A and PIK3CA mutations were found in JHOC9 and TAYA while MLH1 mutation was found in RMG2. Of note, TP53 mutation was found in TAYA. ARID1A mutation was also found in Mesenchymal lines, OVTOKO and RMG5. Two Mesenchymal lines (KOC7C and RMG5) were found to harbor BRCA1 mutations with RMG5 also harboring a BRCA2 mutation. When cells were cultured in an anchorage independent condition, the percentage of apoptotic cells significantly increased in the Epithelial compared to the Mesenchymal lines.

Conclusions

Existing OCCC cell lines are heterogeneous and recapitulate certain molecular features common in OCCC such as ARID1A and PIK3CA mutations. Uncommon mutations such as BRCA1/2 were also discovered. These OCCC lines will be useful to interrogate for therapeutic vulnerabilities to enhance our understanding of this devastating disease.

Clinical trial identification

Legal entity responsible for the study

National University of Singapore

Funding

None

Disclosure

All authors have declared no conflicts of interest.