(A) 30,000 dissociated sphere-forming cells derived from A2780 cells (platinum-sensitive and -resistant) were treated with CDDP (1.67µM) or SGI-110 (100nM) alone or in combination. Representative images are shown. Scale bar, 200µm. (B) Quantitative analysis of spheres formation assay. (C) 500 ALDH(+) cells derived from A2780_CR5 were treated with cisplatin (1.67µM), SGI-110 (100nM), alone or in combination, and allowed to recover for 4 days. The number of spheres (left) and colonies (right) was counted in 14 days and 7 days, respectively. (D) Sphere formation assay of 500 untreated and SGI-110 (100nM) treated ALDH(+)/ALDH(−) cells isolated from cultured A2780_CR5 (platinum-resistant). Representative images were shown in the upper panel, Scale bar, 200µm. Quantification of sphere formation assay is shown below the images. Cells were plated in triplicate and spheres were mechanically disassociated every 7 days and counted on the Day 14. (E) Colony formation assay of 500 untreated and SGI-110 (100nM) treated ALDH(+)/ALDH(−) cells isolated from cultured A2780_CR5. Cells were plated in triplicate. Colonies were stained with crystal violet and counted on day 8. (F) ALDH(+) cell differentiation assay. Average number of ALDH(+) population present in untreated or SGI-110 (100nM) treated A2780_CR5_ALDH(+) cells. ALDH(+) cells were cultured in RPMI or DMEM condition for 7, 14, 21, 28, and 42 days. Mean values ± SD of three independent experiments in triplicate are reported (*: P<0.05, **: P<0.01, ***: P<0.001).