Fig. 2: RS-35d, S-35d and R-35d differential synergism with olaparib and their diverse impact on cell viability.

a Cell viability measured after 72 h exposure to 40 µM RS-35d, 20 µM S-35d or 20 µM R-35d alone or in combination with 10 µM olaparib (OLA) in BxPC-3, HPAC, Capan-1 and H-6037 cells. b Gene expression profile of the main HR genes in the employed three PDAC cell lines. Relative gene expression values were obtained from the Cancer Dependency Map portal Depmap (https://depmap.org/portal/) and are inferred from RNA-seq data using the RSEM tool and are reported after log₂ transformation, using a pseudo-count of 1; log₂(TPM + 1). c Interaction index (i. index) of RS-35d, S-35d or R-35d association with olaparib in BxPC-3, HPAC, Capan-1 and H-6037 cell lines. I. index values were made explicit in their respective graphs when the drug association showed synergism (i. index < 0.8). Cell death assessment by CellTox Green (d) and vital dyes staining (e) measured after 72 h exposure to 40 µM RS-35d, 20 µM S-35d or 20 µM R-35d alone or in combination with 10 µM OLA in BxPC-3 cells; d RS-35d, S-35d or R-35d alone or in combination with 10 µM OLA in BxPC-3 cells; e Representative images of DAPI-stained nuclei and the corresponding PI-stained cells (scale bar, 50 μm) and analysis of PI-positive cells (%). Results are expressed as mean ± SD (n = 3). Statistical analysis was performed with two-way ANOVA followed by Tuckey’s multiple comparison test, with ^§p < 0.05, ^§§p < 0.01 or ^§§§p < 0.001 vs CTRL; ^#p < 0.05, ^##p < 0.01 or ^###p < 0.001 vs 10 µM OLA; *p < 0.05, **p < 0.01 or ***p < 0.001 vs RAD51-BRCA2 inhibitor alone.