[Effect of miR-202 on the growth of multiple myeloma cells via regulating B cell-activating factor and the underlying mechanism].

Objective: To explore the regulating effect of miR-202 on B cell-activating factor, and check whether the regulation influences the growth of multiple myeloma cells.

Methods: The potential binding sites of BAFF for miR-202 were predicted using bioinformatics software. Luciferase reporter gene analysis was used to evaluate the regulatory effect of miR-202 on BAFF. Human multiple myeloma U266 cells were transfected with has-miR-202-mimics, has-miR-202-inhibitor, siBAFF and their negative controls, respectively. After above treatments, BAFF mRNA and protein levels were detected by real-time PCR and Western blot analysis, and the proliferation and apoptosis in the multiple myeloma (MM) cells were examined by WST-1 and annexin V-FLUOS assay, respectively.

Results: The BAFF mRNA expression levels in the untransfected group, has-miR-202-3P-mimics transfected group, has-miR-202-3P-inhibitor transfected group and siBAFF transfected group were 1.040 ± 0.057, 0.573 ± 0.073, 1.205 ± 0.097 and 0.368 ± 0.052, respectively. BAFF mRNA expressions in U266 cells transfected with has-miR-202-3P-mimics and siBAFF were significantly decreased compared with that in the untransfected group (P < 0.05). The BAFF protein expression level of each group was consistent with the mRNA assay result. The absorbance value in 450 nm of the untransfected group, has-miR-202-3P-mimics transfected group, has-miR-202-3P-inhibitor transfected group and siBAFF transfected group were 1.063 ± 0.052, 0.714 ± 0.045, 0.936 ± 0.066 and 0.764 ± 0.053, respectively. In comparison with the untransfected group, the absorbance value at 450 nm of has-miR-202-3P-mimics and siBAFF transfected groups was significantly reduced (P < 0.05). The cell apoptosis rates of untransfected group, has-miR-202-3P-mimics transfected group, has-miR-202-3P-inhibitor transfected group and siBAFF transfected group were 26.2%, 49.6%, 21.1% and 30.7%, respectively. Therefore, the cell apoptosis rate of has-miR-202-3P-mimics transfected group was significantly increased than that of the untransfected group (P < 0.05). p-JNK protein expression level was decreased in the has-miR-202-3P-mimics transfected cells.

Conclusions: MiR-202 can inhibit the proliferation and induce apoptosis in MM cells via regulating BAFF. JNK/SAPK signaling pathway is involved in the regulation of BAFF by miR-202.