Study on the Association Between miRNA-202 Expression and Drug Sensitivity in Multiple Myeloma Cells.

An increasing amount of experimental evidence has shown that miRNAs play a causal role in hematologic tumorigenesis. In this study, we characterized the role of miR-202 in multiple myeloma (MM) drug sensitivity. The potential binding site of miR-202 and B cell-activating factor (BAFF) was confirmed by luciferase reporter assay. MM cells were transfected with miR-202 mimics and inhibitor. Cells growth was measured by WST-1 cell proliferation assay and Annexin V-FLUOS apoptosis assay. BAFF and miR-202 mRNA levels were measured by real-time PCR. Meanwhile, BAFF, Bcl-2 family survival proteins and MAPK pathway proteins were measured by Western blot. It was found that miR-202 was functioned as a modulator of BAFF expression. miR-202 over-expression sensitized MM cells to bortezomib (Bort) but less to Thalidomide (Thal) and dexamethasone (Dex). miR-202 mimics in combination with Bort inhibited MM cell survival more effectively as compared with Bort treatment alone. Our study also provided experimental evidence that JNK/SAPK signaling pathway was involved in the regulatory effect of miR-202 on drug resistance of MM cells. These results suggest that the regulatory mechanism of miR-202 expression may be a promising target for fine-tuning anti-myeloma therapy.