[Expression of alternatively spliced human tissue factor in acute leukemia cells]

The high expression of tissue factor (TF) is related to the coagulation disorder in acute leukemia. TF in blood circulation is mainly expressed in cells, microparticles (MP) and alternatively spliced human tissue factor (asHTF). To elucidate the role of TF in the coagulation disorder of acute myeloid leukemia (AML), RT-PCR was performed on 6 common AML cell lines NB4, HL-60, Kasumi-1, U937, K562 and THP-1. The results showed that only NB4 and U937 cells expressed baseline full-length TF and asHTF which were proved by sequencing. The flow cytometric detection, TF activity and TF antigen tests in NB4 and U937 cells revealed that the asHTF was expressed in trace amount and almost had no activity, while the TF antigen and activity in microparticles were significantly higher than that in asHTF. It is concluded that asHTF may play an unimportant role in the coagulation disorder of AML. Microparticle associated tissue factor (MP-TF) is the predominant source of TF activity released from AML cells.