Figure 5.

Cells do not acquire resistance to Ponatinib as rapidly as Dasatinib and Bosutinib. (A) Schematic of long-term treatment with Dasatinib, Bosutinib and Ponatinib. DLD-1 cells were treated with continuous, increasing doses of Dasatinib, Bosutinib and Ponatinib for six weeks and then assessed for cell viability in comparison to control DLD-1 cells. (B) DLD-1 (■) and DLD-1-Das cells (□), were treated with ± Dasatinib or Ponatinib for 72 h. Cell viability was then determined using a commercially available Cell Titer-Glo kit and samples read on a bioluminometer. Data is expressed as % viability compared to untreated control cells ± S.D. (C) DLD-1 (■) and DLD-1-Bos cells (□), were treated with ± Bosutinib or Ponatinib for 72 h. Cell viability was then determined as outlined above. (D) DLD-1 (■) and DLD-1-Pon cells (□), were treated with ± Ponatinib for 72 h. Cell viability was then determined as outlined above. (E) DLD-1 (■) and DLD-1 cells that had been co-cultured in the presence of Ponatinib for 15, 35 and 45 weeks (□), were treated with ± Ponatinib for 72 h. Cell viability was then determined as outlined above. (F) SW48, DIFI and LIM1215 cells (■) and their counterparts that had been co-cultured in the presence of Ponatinib for greater than four months (□), were treated with ± Ponatinib for 72 h. Cell viability was then determined as outlined above from at least three independent experiments, each with 3 experimental replicates; * p < 0.05; ** p < 0.01.