Effects of hemin and thermal stress exposure on JWA expression.

To investigate the expression of JWA after hemin and (or) thermal stress exposure, we treated K562 (chronic myelogenous leukemia cells) cells with different doses of hemin and thermal stress using different exposure times. The expression of JWA protein was determined by Western blot analysis. Reverse transcription-polymerase chain reaction was carried out to determine JWA mRNA expression. JWA promoter transcription activity analysis was performed by chloramphenicol acetyl transferase-enzyme linked immunosorbent assay (CAT-ELISA). The expression of JWA protein was significantly increased by up to (3.23 ± 0.57) folds compared to the control in K562 cells after hemin treatment (50 μM for one week), and a similar pattern was observed in the cells after treatment with thermal stress (42°C) for 2 hours [increased by (8.00 ± 1.73) folds]. The expression of JWA mRNA was also significantly elevated by up to (1.37 ± 0.06) folds in K562 cells treated with hemin (30 μM for 48 hours), and a similar regulatory pattern [increased by (1.87 ± 0.13) folds] was observed with thermal stress exposure (42°C) for 30 minutes. However, a combined antagonistic effect was observed in the treatment of K562 cells with hemin (30 μM, 48 h) followed by thermal stress (42°C, 30 min). CAT-ELISA further confirmed that either hemin or thermal stress treatment could up-regulate JWA transcription activity, however, the effects could be counteracted partly by treatment with a combination of both. Hemin and thermal stress might regulate JWA expression via distinct intracellular signal transduction pathways.