[Effects of all-trans retinoic acid and arsenic trioxide on tissue factor expression of acute promyelocytic leukemia cells].

OBJECTIVE

To investigate the effects of all-trans retinoic acid (ATRA) and arsenic trioxide (As(2)O(3)) on both tissue factor (TF) expression and procoagulant activity (PCA) of acute promyelocytic leukemia (APL) cells in vivo and in vitro.

METHODS

The PCA of APL blasts freshly isolated from the APL patients treated with ATRA or As(2)O(3) was detected using a one-stage clotting assay; the TF antigen was detected by ELISA and TF mRNA by RT-PCR. The maturation sensitivity (NB4) or resistant subclones (NB4-R1) of the promyelocytic NB4 cell line as well as U937 cells transfected with pMSCV-PML-RARa treated with or without ATRA or As(2)O(3) were also examined.

RESULTS

Both ATRA and As(2)O(3) time-dependently down-regulated the TF antigen, its mRNA transcription and membrane PCA of APL cells in vivo and in vitro. The TF antigen level in PML-RARa(+) U937 cells was significantly higher than that in U937 cells transfected with retrovirus vector (890 pg/8 x 10(5) +/- 80 pg/8 x 10(5) cell and 728 pg/8 x 10(5) +/- 86 pg/8 x 10(5) cell, respectively). Both ATRA and As(2)O(3) down-regulated the TF antigen of the U937 cells transfected with or without PML-RARa.

CONCLUSION

Tissue factor expression and PCA of APL cells can be down-regulated by ATRA and As(2)O(3). By down-regulating the TF expression, As(2)O(3) might also be used to improve the DIC-related hemorrhage of APL. It is also suggested that elevated TF antigen in the PML-RARa(+) U937 cells may be related with the fusion protein PML-RARa, while the down-regulation effect of ATRA and As(2)O(3) on the TF expression of U937 cells might not be involved in the fusion protein.