[The Relationship between MicroRNA Expression Profiling in Imatinib-Resistant Cell Line K562/G and Potential Mechanism through FOXO3/Bcl-6 Signaling Pathway]

Objective: To investigate the drug resistant related FOXO3/Bcl-6 signaling pathway in K562/G cell line and its related microRNA(miRNA) mechanisms.

Methods: The drug resistance potency of imatinib on K562/G was detected by MTT assay. The expression of FOXO3 and Bcl-6 proteins in K562 and K562/G cells was detected by Western blot. Real-time PCR (RT-PCR) was used to detect the expression of FOXO3 and Bcl-6 mRNA. The miRNA expression profiling in K562 and K562/G cells was analyzed by microarray technique, and the miRNA targeted to FOXO/Bcl-6 signaling pathway was identified.

Results: The expression of FOXO3 and Bcl-6 protein was significantly increased in K562/G cells as compared with that in K562 cells (P<0.01), the expression level of Bcl-6 mRNA showed no increase in K562/G cells. However, FOXO3 mRNA was up-regulated in K562/G cells (P<0.05). MiRNA microarray results showed that 109 miRNAs were expressed differentially in K562 and K562/G cells. The expression of 81 miRNAs were up-regulated while 28 miRNAs were down-regulated. Through reverse prediction by bioinformatics, miR-6718-5p, miR-5195-5p, miR-4711-3p, miR-4763-5p, miR-4664-5p and miR-3176 were related to FOXO/Bcl-6 signaling pathway.

Conclusion: The FOXO3/Bcl-6 signaling pathway contributes to imatinib resistance in K562/G cell line, and the miRNA expression profiles showed significant differences between K562/G and K562 cells.