[Effect of siRNA-Interfering β-Catenin Expression on MDR of Human Multiple Myeloma Cell Line]

To investigate the effecr of siRNA-interfering β-catenin expression on drug-resistance of multiple myeloma cells.

The multiple myeloma cell line RPMI-8226 was cultured in vitro. The maphalan-resistant cell model was established by concentration gradient ascending of durg, then the drug-resistant cell line was instantaneously transfected with β-catenin siRNA, the sensitivity of RPMI 8226 cells to maphalan was detected by CCK-8 meltod before and after the transfection with siRNA; the mRNA and protein expression of β-catenin was detected by qRT-PCR and Western blot respectively, the apoptosis of cells was detected by flow cytometry.

IC₅₀ of maphalan decreased from (5.29±0.19) μmol/L to (1.88±0.64) μmol/L, suggesting that the deplation of β-eatenin restored the sensitivity of drug-resistant cell line RPMI-8226 to malphalan. The Western blot showed that after the instaintaneous transfection with β-catenin siRNA, the β-catenin protein expression level obviously decreased, compared with level before transfection. After transfection, the maplalan-inducing apoptosis rate of cells increased from (35±0.5)% to (54±0.4)%, suggesting that the β-catinin gene may correlated with drug-resistance of cells. Interfering the expression of β-catenin gene could enhance the sensitivity of drug-resistant RPMI-8226 cells to maphalan.

The β-catenin siRNA interfereuce can inhisit the β-catenin gene expression in Wnt/β-catenin signaling pathway, suppress the cell proliferation, enhence the toxicity of maphalan on drug-resistant RPMI-8226 cells, thus result in increase of cell apoptosis.