Figure 5. Comparison of Tpmt-associated phenotypes in A172 isogenic cells.

Tpmt protein activity was measured in A172^mock and A172^Tpmt cell lines. (a) Tpmt protein activity was significantly higher in A172^Tpmt (p<0.05); additionally, (b) A172^Tpmt showed a significantly higher resistance to TG-induced toxicity when compared to A172^mock as determined by the MTT cell viability data (p<0.005) and (c) by IC₅₀ values (p<0.05). (d) The alkaline comet assay was used to compare TG-induced DNA damage. A172^mock displayed a significantly higher DNA damage than A172^Tpmt (p = 0.03) as measured by mean comet tail moment. Bars represent the means; whiskers represent the standard deviation (±). * p<0.05.