219 Effect of olaparib treatment on cell cycle, senescence and cell death in ovarian cancer cells

Objectives

High-grade serous ovarian cancer (HGSOC) is the most frequent and deadly histological type of ovarian cancer. Targeted treatment approaches, such as PARP inhibitors, have brought significant improvement in management of this disease. Here we analyzed molecular mechanisms of olaparib influence on ovarian cancer cells.

Methods

We used our newly established HGSOC cell line OVPA8 (ECACC #1906260¹) and three other lines (A2780, SKOV3, KURAMOCHI). BRCA1/2 mutations were analyzed by Sanger sequencing and NGS. Cells were treated by olaparib (AZD2281). Metabolic activity and viability were assessed using AlamarBlue and crystal violet assay, respectively. Half maximal inhibitory concentrations (IC50) were determined using GraphPadPrism software. Cell death and cell-cycle distribution were analyzed by flow cytometry.

Results

NGS analysis revealed BRCA1 pathological mutation c.3700_3704delGTAAA (p.Val1234Glnf) and loss of heterozygosity in BRCA2 in OVPA8. BRCA2 pathological mutation c.6952C>T (p.Arg2318Ter) was described in KURAMOCHI, BRCA2 mutations of unknown significance in A2780 (c.T8195G, p.L2732X) and SKOV3 (c.7364A>G, p.H2455R).² The IC50 values were 3.99µM, 5.13µM, 6.77µM and 25.6µM for OVPA8, A2780, KURAMOCHI and SKOV3, respectively. Olaparib treatment resulted in G2/M arrest in all cell lines, increased senescence and cell death (except SKOV3).

Conclusions

All analyzed cell lines, except SKOV3, had low olaparib IC50 values. The same correlation was found for the level of cell death and senescence what may be related to the functional status of BRCA1/2. Cell cycle G2/M phase arrest was observed in all ovarian cancer cell lines.

References

Tudrej, P. et al. 2018-10.3390/ijms19072080 Stordal, B., et al. 2013-10.1016/j.molonc.2012.12.007 A.J.C. was co-financed by the European Union through the European Social Fund (grant POWR.03.02.00-00-I029).