Study On The Expression And The Function Of IFP35 In Chronic Myelogenous Leukemia Cells

Objective:Chronic myeloid leukemia (CML) is typified by robust marrow and extramedullary myeloid cell production. Interferon alpha (IFN-α) is one of the most effective agent for CML treatment. But some CML patients appear resistance after IFN-αtreatment. Our laboratory had discovered IFP35 was over expressed in IFN-a sensitive KT-1/A3 CML cell line, but not in IFN-a resistance KT-1/A3R. IFP35 (Interferon-induced Protein 35) is the interferon induced protein. Through study the moleculer expression in different CML cell line after IFN-αtreatment, to find out the functions of IFP35 protein participating in the interferon induced pathway.Methods:This study uses IFN-a treatment diferent sensitive CML cell lines KT-1/A3 and KT-1/A3R cells as the experimental models, uses RT-PCR and Western blotting to analyze the difference of IFP35 expression in the conditions with or without the inducement by IFN-a; based on these study, pcDNA3.1+/IFP35 recombinant expression vector was constructed and transfected into KT-1/A3 cells and KT-1/A3R cells. Proliferation and growth states of KT-1/A3 and KT-1/A3R cells in different groups were analyzed by using cell counting assay, and drawing the cell growth curve diagrams. Cell apoptosis rates were examined by flow cytometry (FCM) at 48h after IFN-a induction of KT-1/A3 and KT-1/A3R cells.Results:RT-PCR results showed that IFP35 gene expression in KT-1/A3 and KT-1/A3R cells was significantly increased by IFN-a induction. Western blotting results showed that IFP35 protein expression induced by interferon in KT-1/A3 cells was higher than that in KT-1/A3R cells. The pcDNA3.1+/IFP35 recombinant expression vector after transfection do not promote proliferation, but can effectively reduce the interferon induced inhibiting effect.Conclusions:IFN-a can effectively induce IFP35 gene and protein exprssion, IFP35 protein expression induced by interferon in KT-1/A3 cells in much higher than that in KT-1/A3R cells. While the cell counting of KT-1/A3 and KT-1/A3R cells transfected with pcDNA3.1+/IFP35 recombinant expression vector and control vector with or without the induction of IFN-a was set up, the results suggest that IFP35 protein may regulate the IFN-a induced pathway, through reducing sensitivity to IFN-a treatment of CML cells.