Production of CC chemokines induced by ATRA are restricted in TG2 knockdown NB4 cells. NB4 cells (105 cells/mL) and its sublines (virus control and TG2-KD NB4 cells) were cultured in presence of 1μM ATRA for 48 and 72 hours. (A) Relative expressions of CCL2, CCL3, CCL20, and CCL24 chemokines during the ATRA-induced differentiation of control and TG2-KD NB4 cells are presented by a heat map. Results are derived from the microarray experiment. (B) Relative mRNA expressions of CC chemokines were determined at the indicated time points by real-time Q-PCR. Expression levels are normalized to the level of the cyclophilin. (C) Protein levels of CC chemokines were quantified in supernatants of NB4 cells at the indicated time points by ELISA. Figures show typical protein level patterns from 2 or 3 independent experiments measured in duplicates. (D) Chemoattractive effect of supernatant of differentiating control, virus control, and TG2-KD NB4 cells on peripheral white blood cells was evaluated by migration assay. Migration experiments were performed 2 times with 3 parallels in each experiment. Statistical significance between wild-type and TG2-KD cells was determined by using the Student t test P < .05.