[Reversal Roles and Its Mechanism of Asiatic Acid on Multidrug Resistance in K562/ADR Cells Through the Wnt/β-catenin Pathway].

Objective: To investigate the reversal effect and mechanism of asiatic acid (AA) on multidrug resistance in human adriamycin (ADR) chronic myeloid leukemia K562/ADR cells.
Methods: CCK-8 assay was used to detect the resistance of K562 cells and K562/ADR cells to ADR. CCK-8 assay was used to detect the effect of AA on K562/ADR cell viability and adriamycin sensitization. After K562/ADR cells were treated with non-toxic doses of AA(10, 20 μmol/L), the average fluorescence intensity of ADR was detected by flow cytometry. Real-time quantitative PCR was used to detect the expression levels of MRP1, P-gp, β-catenin, C-myc and cyclinD1 mRNA. Western blot was used to detect the expression levels of MRP1, P-gp, β-catenin, C-myc and cyclinD1 proteins. Western blot assay was used to detect the expression levels of MRP1, P-gp, β-catenin, C-myc and cyclinD1 proteins in K562/ADR cells treated with 20 μmol/L AA and Wnt/β-catenin pathway agonist WAY-262611 (5 μmol/L).
Results: The CCK-8 assay showed that the drug resistance of K562/ADR cells was 56.57 times that of K562 cells, showing stable drug resistance, and the difference was statistically significant ( P < 0.05). AA inhibited the proliferative activity of K562/ADR cells in a concentration-dependent manner（ r =0.9666）. Compared with 0 μmol/L AA group, the 10 and 20 μmol/L AA groups could significantly enhance the average fluorescence intensity of intracellular ADR ( P < 0.05), and reverse the cell resistance to ADR ( P < 0.05). The mRNA and protein expressions of MRP1, P-gp, β-catenin, C-myc and cyclinD1 in cells were down-regulated ( P < 0.05). Compared with 20 μmol/L AA group, the expression levels of MRP1, P-gp, β-catenin, C-myc and cyclinD1 protein in 20 μmol/L AA+WAY group were significantly increased ( P < 0.05).
Conclusion: AA inhibits K562/ADR cell proliferation in a concentration-dependent manner and reverse their resistance to ADR, the reversal mechanism may be related to the down-regulation of MRP1 and P-gp expression after inhibiting Wnt/β-catenin signaling pathway.