The comparison of miRNA - 1236's and exogenous small double - stranded RNAs' activating effects on p21 expression in bladder cancer cells

Abstract

Objective Four pairs of synthetic candidate small double stranded RNAs (dsRNAs) with complete complementarity to the microRNA-1236 (miR-1236) target site of p21 promoter: dsP21-242, dsP21-243, dsP21-244 and dsP21-245 (dsP21-243 with best base-pairing to miR-1236). To investigate the differences of dsRNAs’ and miR-1236’s activating effects on p21 expression in bladder cancer cells T24 and EJ. Methods Referring to small activate RNA (saRNA) design principles, dsRNAs were designed and synthesized. dsControl (negative control), miR-1236 (positive control) or dsRNAs (experimental group) were respectively transfected into T24 and EJ cells. The analysis of p21 mRNA expression levels were conducted by real-time fluorescent quantitative polymerase chain reaction (FQ-PCR) and reverse transcriptase-polymerase chain reaction (RT-PCR). Western blotting was applied to detect the p21 protein expression levels. Results FQ-PCR analysis showed that only dsP21-245 in experimental group can significantly promote the expression of p21 mRNA in both cell lines. Compared with dsControl transfections, the up-regulation of p21 mRNA was 2.32-fold in T24 cells (P 0.05). RT-PCR confirmed the corresponding changes p21 mRNA expression levels in both cell lines. Western blotting revealed that the induction of p21 protein levels were consistent with the increase of p21 mRNA expression in both cell lines. The remaining three pairs of dsRNAs failed to up-regulated p21 gene expression in both cell lines (P>0.05). Conclusion Synthetic dsP21-245 can significantly promote the over-expression of p21 in bladder cancer cells. Besides, there are no significantly differences about the p21-activated abilities of dsP21-245 and miR-1236. Key words: MicroRNA; Double stranded RNA; RNA activation; p21; Bladder cancer