ITPA protects against HAP-induced DNA breaks.

<p>Alkaline comet assay data reveals that as compared to the control and non-targeting shRNA-expressing cell lines, ITPA knockdown cells accumulated elevated levels of DNA breaks after 24 hours of treatment with HAP. At high doses of HAP, the sizes of the comet tails in the ITPA knockdown cells were too large to be quantified. The assay was performed at lower doses of HAP treatment in order to obtain measurable comet tails. As compared to the cells with vector, the overexpression of <i>HAM1</i> suppressed the accumulation of HAP-induced DNA breaks in the <i>ITPA</i> knockdown cells. Statistical differences were measured by one-way ANOVA followed by Dunns multiple comparisons for column analysis. By two-way ANOVA, p = 0.008. Post-test analysis revealed differences (p<0.05) for knockdown versus knockdown+<i>HAM1</i> and knockdown+vector versus knockdown+<i>HAM1</i>. No difference in levels of DNA breaks was observed for hydrogen peroxide treatment for all three cell lines.