[Expression level of TRF1 protein in human acute leukemia and its relationship with activity of telomerase]

The study was aimed to investigate the expression level of TRF1 protein in human acute leukemia and relationship between expression level of TRF1 protein and activity of telomerase. A quantitative Western blot technique was developed using anti-TRF1(33 - 277) monoclonal antibody and GST-TRF1 fusion protein as a standard to further determine the expression level of TRF1 protein in total proteins extracted from clinical specimens. 20 cases of acute leukemias were studied when 11 normal volunteer's bone marrow was used as control. The results showed that the expression level of TRF1 protein in normal bone marrow (2.217 +/- 0.461 microg/microl) was significantly higher than that in bone marrow of acute leukemia patients (0.754 +/- 0.343 microg/microl) (P < 0.01). There was no remarkable difference of expression level of TRF1 protein between ALL and ANLL (0.628 +/- 0.281 microg/microl vs 0.844 +/- 0.360 microg/microl, P > 0.05). After chemotherapy, TRF1 expression level of patients with complete remission raised (0.772 +/- 0.307 microg/microl vs 1.683 +/- 0.344 microg/microl, P < 0.01), but lower than that of normal (2.217 +/- 0.461 microg/microl, P < 0.01). TRF1 expression level of patients without complete remission was not remarkable different after chemotherapy (0.726 +/- 0.443 microg/microl vs 0.894 +/- 0.338 microg/microl, P > 0.05). TRF1 expression level of patients with complete remission was higher than that in patients without complete remession (1.683 +/- 0.344 microg/microl vs 0.894 +/- 0.338 microg/microl, P < 0.01). For all sample the telomerase activity was determined. It was confirmed that the activity of telomerase in normal bone marrow was lower than that in bone marrow of acute leukemia patients (0.125 +/- 0.078 microg/microl vs 0.765 +/- 0.284 microg/microl, P < 0.01). There was no significantly difference of expression level of TRF1 protein between ALL and ANLL (0.897 +/- 0.290 microg/microl vs 0.677 +/- 0.268 microg/microl, P > 0.05). After chemotherapy, telomerase activity of patients with complete remission reduced (0.393 +/- 0.125 microg/microl), but higher than that of normal (0.125 +/- 0.078 microg/microl, P < 0.01). It is concluded that expression level of TRF1 protein in AL patients is significantly decrese and associated with therapeutic efficaciousness and the activity of telomerase (P < 0.001).