OBJECTIVETo investigate the effects of Notch1 gene silencing on the proliferation and apoptosis of multiple myeloma cells, and to find the new targets for the treatment of multiple myeloma.

METHODSNotch1-shRNA targeted silencing Notch1 gene was transfected into multiple myeloma RPMI8226 cells, the CCK-8 and flow cytometry were used to detect the proliferation and apoptosis of myeloma cells after Notch1-shRNA transfection, the real-time fluorescence quantitative PCR was used to analyze expression level of Notch1 mRNA, and the Western blot were used to detect the expression level of Notch1 signaling pathway-related protein, such as Hes-1, Jagged-1, Jagged-2, BCL-2, PTEN, AKT and P-AKT.

RESULTSThe mRNA and protein expression levels of Notch1-shRNA transfected cells were significantly inhibited in the experimental group assayed by real time fluorescence quantitative PCR and Western blot, the mRNA and protein expression level were down-regulated to 66% + 0.1%, 88% + 3.4% respectively, as compared with the control group(P<0.05). CCK-8 results confirmed that the cell proliferation rate was significantly decreased in the experimental group 48 hours after transfection. Flow cytometry results showed that the cell apoptosis rate was significantly higher in the experimental group than that in the control group. The expression levels of downstream protein Hes1, p-AKT and BCL-2 were decreased, the level of PTEN increased significantly after Notch1 gene silencing.

CONCLUSIONNotch1 gene silencing by transfection of Notch1-shRNA can inhibit the proliferation of myeloma cells and induce their apoptosis, and its mechanism is related to the activation of PTEN gene and p-AKT signaling. Notch1 signal can be used as a potential target for multiple myeloma therapy.