IL-24 expression is upregulated after PC1-p30 overexpression or IL-13 treatment. A: semiquantitative RT-PCR of IL-24 from PC1-p30 overexpression in HEK293 T cells. RT, reverse transcriptase; nt, no template. B: quantitative PCR analysis of IL-24 expression after overexpression of PC1-p30 in human embryonic kidney (HEK) 293 T cells (*P < 0.05, one-tailed t-test). C: quantitative PCR analysis of mouse IL-24 mRNA in mouse inner medullary collecting duct (IMCD) cells treated with vehicle control (PBS) or 100 ng/ml mouse IL-13 (*P < 0.05, one-tailed t-test). D, top: quantitative PCR of human kidney 2 (HK2) cells treated with vehicle (PBS), 100 ng human IL-4 for 24 h with or without prior treatment with 500 nM pyridone-6 (P = 0.0002, one-way ANOVA). D, bottom: immunoblot of HK2 cells treated with vehicle (PBS), 100 ng IL-4 for 1 h with or without 30 min prior treatment with 500 nM pyridone-6 (representative of n = 3).