Polymerase synthesis and potential interference of a small-interfering RNA targeting hPim-2

Aim: To synthesize three small-interference RNAs (siRNAs) by T7 RNA polymerase-catalyzed reaction, and to investigate their efficacy on modulating the expression of serine/threonine kinase Pim-2 in human colon cancer cell line. Methods: siRNA I, II and III were synthesized by T₇ RNA polymerase-directed in vitro transcription, then transfected into human colon cancer cells SW-480. After incubation for 6 h at 37 °C, 100 mL/L FBS in RPMI 1640 was substituted in each well. After the transfection was repeated twice to three times in each kind of siRNA, hPim-2 mRNA and protein expression were measured by RT-PCR and Western blotting, respectively. Results: Compared to the control group, after transfected for 48 h with hPim-2 siRNA I, II and III, the relative inhibition rates of hPim-2 mRNA expression in colon cancer cells were 65.4% (P<0.05),46.2% (P< 0.05) and 56.1% (P<0.05), respectively. The protein level of hPim-2 was decreased at 72 h compared to the untransfected cells. The relative inhibition percentages of hPim-2 protein by siRNA I, II, III were 61.6% (P<0.05), 45.8% (P<0.05) and 55.6% (P<0.05), respectively. Conclusion: The in vitro transcribed siRNAs can be useful for silencing oncogene hPim-2 expression specifically and efficiently. This may open a new path toward the use of siRNAs as a gene-specific therapeutic tool.