Abstract: To study the specific effect of silencing of CD55 gene by small interfering RNA (siRNA) on the growth of human pancreatic cancer cell line BxPC-3. Methods Three CD55-specific siRNAs and one negative siRNA were designed and was transfected into human pancreatic cancer cell line BxPC-3 by Lipofectamine 2000.Quantitative real-time PCR(qRT-PCR) and Western blot were used to test the expression levels of CD55 mRNA and protein respectively. And flow cytometry were used to detect apoptosis, proliferation and cell cycle of target cells. Results: One of three CD55-specific siRNAs, siRNA3 could silence the expression of the CD55 gene. The expression levels of CD55 mRNA and protein decreased remarkably.The cells transfected with siRNA3 were found to increase apoptosis and reduce proliferation significantly;the target cells stagnated in phase G1 after transfection(P<0.05). Conclusion: SiRNA-mediated silencing of the decay accelerating factor(CD55) can effectively affect the biological behavior of human pancreatic cancer cell line BxPC-3.

Key words: Pancreatic carcinoma, RNA interference, CD55, Cell apoptosis, Cell proliferation, Cell cycle