Figure 3. The effect of cisplatin on ATC cells.

(A) Representative phase contrast microscopy images of THJ-11T parental monolayer-derived cells exposed to the indicated dose of cisplatin for 48 hours. (B) Dose-dependent inhibition of growth in all ATC cell lines. IC₅₀ values are as shown for each cell line. (C) Comparison of in vitro resistance to cisplatin of the parental monolayer cells and spheroid-forming cells. The THJ-11T and THJ-16T parental monolayer-derived cells and thyrosphere-derived cells were treated with 10 µM of cisplatin and the fraction of proliferating cells remaining was subsequently estimated based on the Alamar Blue cell proliferation assay. All experiments were performed in triplicate. ****, P<0.0001; ***, P<0.001; **, P<0.05.