Characterisation of Ovarian Cancer Cell Line NIH-OVCAR3 and Implications of Genomic, Transcriptomic, Proteomic and Functional DNA Damage Response Biomarkers for Therapeutic Targeting.

Alice Bradbury,Rachel O’Donnell,Sweta Sharma Saha,Yvette Drew,Nicola J Curtin

doi:10.3390/cancers12071939

Alice Bradbury, Rachel O’Donnell + Show 3 more

Open Access

https://doi.org/10.3390/cancers12071939

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Abstract

In order to be effective models to identify biomarkers of chemotherapy response, cancer cell lines require thorough characterization. In this study, we characterised the widely used high grade serous ovarian cancer (HGSOC) cell line NIH-OVCAR3 using bioinformatics, cytotoxicity assays and molecular/functional analyses of DNA damage response (DDR) pathways in comparison to an ovarian cancer cell line panel. Bioinformatic analysis confirmed the HGSOC-like features of NIH-OVCAR3, including low mutation frequency, TP53 loss and high copy number alteration frequency similar to 201 HGSOCs analysed (TCGA). Cytotoxicity assays were performed for the standard of care chemotherapy, carboplatin, and DDR targeting drugs: rucaparib (a PARP inhibitor) and VE-821 (an ATR inhibitor). Interestingly, NIH-OVCAR3 cells showed sensitivity to carboplatin and rucaparib which was explained by functional loss of homologous recombination repair (HRR) identified by plasmid re-joining assay, despite the ability to form RAD51 foci and absence of mutations in HRR genes. NIH-OVCAR3 cells also showed high non-homologous end joining activity, which may contribute to HRR loss and along with genomic amplification in ATR and TOPBP1, could explain the resistance to VE-821. In summary, NIH-OVCAR3 cells highlight the complexity of HGSOCs and that genomic or functional characterization alone might not be enough to predict/explain chemotherapy response.

Highlights

IntroductionA key enabling characteristic of cancer [1], is often caused by defects in DNA damage response (DDR) pathways
Genomic instability, a key enabling characteristic of cancer [1], is often caused by defects in DNA damage response (DDR) pathways
We investigated one of the most widely studied ovarian cancer cell line, NIH-OVCAR3, as a model of High grade serous ovarian cancer (HGSOC), established in 1982 from ascites from a progressive ovarian adenocarcinoma that was resistant to cyclophosphamide, cisplatin and doxorubicin [20]

Summary

Introduction

A key enabling characteristic of cancer [1], is often caused by defects in DNA damage response (DDR) pathways. DNA single strand break repair, in cells with defective homologous recombination DNA repair (HRR). This principle has been successfully applied clinically in HGSOC, where HRR defects are observed in ~50%, and in breast, pancreatic and prostate cancer [3] with HRR defects due to BRCA1/2 mutation. The approval of PARPi in women with HGSOC harbouring HRR defects, and as maintenance therapy in women with platinum sensitive tumours has resulted in significant clinical benefits with prolongation of disease free survival irrespective of BRCA mutation or HRD status [6,7], as well as improved overall survival in platinum-sensitive cases [8]

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Discussion

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