Mir-55 inhibition can reduce cell proliferation and induce apoptosis in Jurkat (Acute T cell Leukemia) cell line

MicroRNAs are small and non-coding RNA molecules with approximately 22 nt in length that cause inhibition of translation or degradation of mRNA. MiR-155 is a kind of molecule with different functions, such as its role in proliferation, apoptosis, inflammation, differentiation, and immunity. One of its best known functions is apoptosis that affects on caspase-3 activity. The main aim of this study was evaluation of miR-155 inhibition effect on cell proliferation and apoptosis induction in Jurkat cells. In this study, Jurkat cells along with MTT assay were used for evaluation of sensitivity to varied concentrations of miR-155 inhibitor (25, 50 and 75 nmol). MiR-155 expression level was analyzed using the quantitative real-time polymerase chain reaction (QRT-PCR). Caspase-3 activity was measured by caspase-3 colorimetric activity assay kit. Unpaired t-test was applied for the analysis of MTT and apoptosis results. Probability of 5% was assumed as statistically significant. According to our results, the use of miR-155 inhibitor increased the activity of caspase-3 by 2 fold in 75 nmol concentration. In this research, we found that the proper increase of miR-155 inhibitor concentration can inhibit miR-155 and consequently increase caspase-3 activity and induce apoptosis in the Jurkat cells leading to cell death ultimately. Apoptosis induction by miRNAs activation or inhibition is probably one of the best and low risk ways of cell death induction in malignancies. Due to role of miR-155 in several cancer cells, it may be used as a therapeutic target in future.