OBJECTIVETo investigate the expression of CSN complex (COP9 signal some subunits) in the patients with acute promyelocytic leukemia (APL) and its significance in the ATRA-induced APL differentiation.

METHODSUsing the NB4 cells as a model, morphologic observation and myeloid differentiation marker CD11b detection were used to monitor ATRA-induced APL differentiation, the expression of CSN complex in cell differentiation was detected by Western blot and reverse transcription real time fluorescent quantitative PCR (RT-qPCR) method. RT-qPCR was also used to detect the relative expression level of COP9 signalosome subunits in the APL patients and remission after treatment.

RESULTSATRA could obviously enhance CD11b expression; the cell morphology showed obvious differentiation characteristics. During the differentiation, the expression of COP9 signalosome subunits was down-regulated by ATRA. Meanwhile, the CSN expression level in newly diagnosed APL patients was much higher than that in controls (non-leukemia) (P < 0.05). The level of CSN expression was obviously down-regulated when APL patients achieved complete remission.

CONCLUSIONThe high CSN expression level in APL patients can be down-regulated by ATRA. CSN complex may have a significant effect on the pathogenesis and therapy of APL.