2.4. Sulforhodamine B assay

Cytotoxicity and proliferation were measured using the SRB assay. 250-3000 cells were plated per well in 96-well plates, treated with 1:4 or 1:2 dilution series of carboplatin (Sigma-Aldrich, Gillingham, UK), mitomycin C (Selleckchem, Houston, TX, USA) paclitaxel (Selleckchem), or olaparib (Selleckchem) and incubated for 5 days at 37°C. These were fixed using 25% trichloroacetic acid (Sigma-Aldrich), and stained with 0.4% w/v sulforhodamine B dye (Sigma-Aldrich). Dye was dissolved by addition of Tris pH 10.5, and optical density at 540nM was measured using a BP800 Microplate Reader (Biohit). Absolute IC₅₀ values were interpolated from concentration-response curves using Graphpad Prism v9.4.1.