Abstract:

BACKGROUND: Real-time quantitative RT-PCR can directly reflect the expression change of fusion gene, but it cannot directly reflect the relative expression of intracellular PML-RARα fusion protein in patients with acute promyelocytic leukemia (APL) before and after all-trans retinoic acid treatment.
OBJECTIVE: To investigate the reliability of immunofluorescence technique in judging the early-stage therapeutic effects of all-trans retinoic acid treatment in APL by dynamic monitoring PML-RARα fusion protein.
METHODS: Immunofluorescence technique was used for detection of PML-RARα protein expression in typical APL cell strain BN4 cells or NB4 cells of patients with APL following all-trans retinoic acid treatment. Real-time quantitative RT-PCR was used for detection of intracellular PML-RARα mRNA expression as control to investigate the reliability of immunofluorescence technique.
RESULTS AND CONCLUSION: Immunofluorescence staining results showed that before all-trans retinoic acid treatment, a large amount of red fusion protein PML-RARα of different size and irregular morphology was observed in BN4 cells in vitro cultured or from patients’ bone marrow; after all-trans retinoic acid treatment, PML-RARα fusion protein in the NB4 cells gradually became regular and was gradually scattered with prolongation of treatment time. Real-time quantitative RT-PCR results showed that the change tendency of PML-RARα mRNA expression was in accordance with immunofluorescence results. This suggests that immunofluorescence for detection of PML-RARα expression can be used for directly judging the therapeutic effects of all-trans retinoic acid treatment.