Study Of Xenograft In Nude Mice On Ovarian Cancer Cell Targeted CD59 By SiRNA

Objectives:In vitro studies had demonstrated that the recombinant vector pSUPER-siCD59 could inhibit CD59 expression on A2780, decrease CD59's protection against complement, and enhance tumor cell susceptibility to complement-mediated cytolysis and facilitate tumor clearance.The present study was to investigate the inhibition effect of pSUPER-siCD59 on CD59 gene and the growth of ovarian cancer in vivo.Methods:A2780 cells were transfected with pSUPER-siCD59 (T group) and blank plasmid (V group) respectively using Lipofectamne2000. After screened with G418 and amplified, these cells together with A2780 without transfection (C group) were subcutaneously injected into nude mice respectively. Xenograft was observed for 30 days continuously. The long axis and minor axis of tumor were measured by vernier caliper every 5 days. The inhibition effect of CD59-siRNA on tumor and CD59 was evaluated by tumor growth curves,in situ hybridization (ISH),immunohistochemistry (IHC),RT-PCR and Western Blot.Results:A2780 cells transfected with pSUPER-siCD59 and pSUPER expressed green fluorescent protein. G418 resistant cells were obtained under the pressure of G418. The tumor growth curves demonstrated that the growth of cells transfected with pSUPER-siCD59 was significantly inhibited (P<0.05) and grew slowly compared with other groups. There was no statistical significance between V and C group in terms of tumor weights and volumes (P>0.05).ISH showed that positive expression of CD59mRNA, presenting blue and purple particles, was mainly in cytoplasm. IHC showed that positive expression of CD59 protein was mainly on cell membrane. ISH,RT-PCR,Western Blot and IHC all showed that the expression of CD59 mRNA and CD59 protein in T group was decreased significantly compared with other groups (P<0.05), while there was no statistical significance between V and C group (P>0.05).Conclusions:Studies of in vivo experiment demonstrated that CD59-siRNA significantly inhibited the expression of CD59, increased the sensitivity of A2780 cells to the complement attack and inhibited the tumor growth. The results may further indicate the role of CD59 in tumor immune escape.