Abstract: Objective To investigate the inhibition of lymphoid enhancer factor-1 (LEF-1) expression in human malignant melanoma cell line A375 by RNA interference method. Methods Sense and antisense oligonucleotides with hairpin structures, targeted specifically at LEF-1 mRNA, were designed, synthesized, then linked to the expression vector psilencer3.1-H1 neo after annealing. After identification, the re-combinant psilencer3.1-H1/LEF-1 siRNA was used to transfect the cultured A375 cells by a liposome-medi-ated method. The cells expressing the recombinant RNA was detected by G418 screening. The mRNA and protein levels were detected by RT-PCR, Western blotting and immunocytochemistry, respectively. Results The expression vector psilencer3.1-H1/LEF-1 siRNA was successfully constructed, and its stable expression in cell clones was achieved. The mRNA and protein levels of LEF-1 were both down-regulated in the trans-fected cells. Conclusion The recombinant of psilencer3.1-HI/LEF-1 siRNA can inhibit the mRNA and protein expression of LEF-1 in A375 cells.

Key words: RNA interference, Melanoma, Gene expression, Lymphoid enhancer factor