Antitumour effects of survivin antisense oligonucleotide carried by nano-high-polymer on colorectal cancer / 中国组织工程研究

ABSTRACT

BACKGROUND: In recent years, nano-carriers have been regarded as the most promising technologies for breakthrough the bottleneck of gene transfer. Polyamidoamine dendrimer (PAMAM) is a kind of new nanometer material. PAMAM can transfer target gene to the cell with high efficiency and lower toxic both in vivo and in vitro.OBJECTIVE: To evaluate the antitumour effects of survivin antisense oligonucleotide (Survivin-asODN) carried by PAMAM on colorectal cancer transplanted subcutaneously in nude mice.DESIGN, TIME AND SETTING: An in vivo experiment regarding tumor gene therapy was performed from February to August in 2008 at the Laboratory of Bionanometer Engineering, Research Institute of Micro/nanometer Science & Technology of Shanghai Jiao Tong University and Central Laboratory of Zhujiang Hospital of Southern Medical University.MATERIALS Human colorectal cancer cells SW620 were from Shanghai Cell Institute of Chinese Academy of Sciences.PAMAM dendrimer was offered by the Bionanometer Engineering Laboratory, Research Institute of Micro/nanometer Science & Technology, Shanghai Jiao Tong University. Lipofectamine ~(TM)2000 was purchased from Invitrogen, USA. Survivin-asODN was synthesized by Shanghai Bioengineering Company.METHODS: The PAMAM and cation liposome were respectively mixed with Survivin-asODN to generate the transfection complex carrying antisense gene. The shape of the complex was observed by transmission electron microscope, the particle size was determined by laser particle size analysator and the zeta potential was measured by an analytical tool. The encapsulating efficiency and release progress in vitro were determined by ultraviolet spectrophotometer in centrifuging method. Human colorectal cancer cells SW620 at logarithmic phase were inoculated into the abdominal region of 18 Blab/C nude mice subcutaneously to produce transplanted tumor models in colorectal cancer nude mice, which were randomly divided into 3 groups liposome, PAMAM and blank control groups. They were injected respectively with Hposome-survivin-asODN complex,PAMAM-survivin-as ODN transfection complex and seroculture liquid. The volumes of tumor were surveyed in the 2 groups.Western blotting method was used to determine the survivin gene expression in the transplanted tumor tissue.MAIN OUTCOME MEASURES: Particle size, zeta potential, gene loading level, encapsulation efficiency, release rate of cationic liposome-survivin-asODN complex and PAMAM-survivin-asODN complex, as well as survivin expression rate and apoptosis rate after transfection, inhibition rate of the transplanted tumor growth, Survivin protein expression and activity in the transplanted tumor cells.RESULTS: The particle size of PAMAM-survivin-asODN complex was smaller (P < 0.01), but the zeta potential was greater (P < 0.05), compared with liposome-survivin-asODN. There was no significant difference between PAMAM and liposome groups in terms of gene loading rate and transfection efficiency. DNA release lasted for 14 days for PAMAM, but only 5 days for liposome.After colorectal cancer cell transfection, survivin protein expression was lower, but apoptosis rate was higher, in the PAMAM-survivin-asODN complex than in the liposome-survivin-asODN complex (P < 0.05).CONCLUSION: PAMAM facilitates delivery of Survivin-asODN into transplanted colorectal cancer cells SW620. As a result,survivin protein expression was decreased, and apoptosis rate was increased in vivo which inhibited transplanied tumour growth.