Objective: To observe the expression of phospholipid scramblase 1 (PLSCR1) in matrine (MAT) induced differentiation of all-trans retinoic acid (ATRA) resistant acute promyelocytic leukemia (APL) cells, and to explore its correlation to cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signal pathway.
Methods: NB4 (an APL cell line sensitive to ATRA) and NB4-R1 (a resistant strain of ATRA) were observed as subjects in this study. Effects of combined treatment of 0.1 mmol/L MAT and 1 [mol/L ATRA on the differentiation of two cell lines were detected using nitroblue tetrazolium (NBT) reduction test and flow cytometry (CD11b). Expressions of PML/RARot and PLSCR1 protein/gene were detected using Western blot and Real-time fluorescence quantitative PCR assay. Meanwhile, H89, PKA antagonist, was used to observe cell differentiation antigen and changes of aforesaid proteins and genes.
Results: MAT combined ATRA could significantly elevate positive rates of NBT and CD11 b in NB4-R1 cells, and significantly down-regulate the expression of PML/RARapha-fusion protein/gene (P < 0.05, P < 0.01). ATRA used alone could obviously enhance the expression of PLSCRI in NB4 cells at protein and mRNA levels (P < 0.01). But the expression of PLSCR1 was up-regulated in NB4-R1 cells, but with statistical.difference only at the protein level (P <0. 01). In combination of MAT, PLSCR1 protein expression was further elevated in the two cell lines (P < 0.01). Besides, there was statistical difference in mRNA expressions in NB4-R1 cells (P < 0.05). All these actions could be reversed by treatment of 10 micromol/L H89 (P < 0.05, P < 0.01).
Conclusion: MAT combined ATRA could significantly induce the differentiation of NB4-R1 cells, and inhibit the expression of PML/RARalpha fusion gene/protein, which might be associated with up-regulating PLSCR1 expression.