Fig. 3: Aggressive DTP cells display increased ATF3 expression, enhanced by cisplatin-treatment and providing a survival benefit.

A Classification of aggressive drug-tolerant persister clones (aDTPs) and non-aggressive control clones (naControl) due to phenotypic and functional characteristics regarding cisplatin sensitivity, colony formation and migration. B aDTP and naControl cells were subjected to increasing cisplatin concentrations and cell viability was measured by CellTiter-Glo after 48 h of treatment. Values represent the average from all three clones in each group. C The half effective concentrations (EC50) of cisplatin for each of the 3 naControl and 3 aDTP clones were calculated from the viability assay data in (B). D ATF3 mRNA expression in each clone within the indicated groups was determined from the RNA-seq data. E Western blot and densiometric analysis of ATF3 protein expression in parental OVCAR-3 cells and in naControl and aDTP clones. (Uncropped Western blots in Supplementary Data Original data). F Western blot analysis of ATF3 protein expression in the aDTP clones 1–3 in the presence or absence of 13 µM cisplatin for 24 h, after transient transfection with non-targeted (CTRL) or ATF3-targeted siRNA (ATF3). (Uncropped Western blots in Supplementary Data Original data). G Flow cytometric analysis of aDTP cells after transfection with control (siControl) or ATF3-targeted siRNA (siATF3) in the presence of 13 µM cisplatin for 24 h. Cell viability was accessed by AnnexinV/PI staining. Data represents mean ± SD. *p < 0.05; **p < 0.01; ***p < 0.001.