Specific expression of the diphtheria toxin A chain gene regulated by the EWS-FLI1 fusion gene in Ewing's sarcoma nude mouse models / 第三军医大学学报

ABSTRACT

Objective To observe the specific expression of diphtheria toxin A chain gene(DTA) in Ewing's sarcoma nude mice models.Methods pS2DTA plasmid was constructed by the Lus gene in pS2 plasmid was replaced with the DTA gene in pIBI30 plasmid,and transformed into DH5?, then amplified.Five nude mice were injected with 2.4?10~(7) SKES1 cells,sacrificed on week 6,and the tumor tissues were implanted onto the back of another 20 nude mice.Till 6 weeks later the diameter of the tumor up to 0.8-1.0 cm,the Ewing's sarcoma nude mice models were successfully established and randomly assigned to receive the injection of 300 ?g lipidosome+100 ?l normal saline(control group) or 300 ?g lipidosome+100 ?l normal saline+100 ?g pS2DTA (experimental group) once a day for 5 d.On day 4 after the therapy finished,4 nude mice of each group were randomly sacrificed and the DTA expression in the tissue of tumor,liver and myocardium was detected by the immunohistochemistry and RTPCR.Results The immunochemical results showed DTA expression in the tissues of control group was all negative while the DTA expression in the experimental group was negative in the tissues of myocardium and liver,positive in tumor tissue.RTPCR showed DTA expression in control group was negative in all tissues while strongly positive in tumor tissue,weakly positive in liver tissue and negative in myocardiac tissue.Conclusion The pS2DTA regulated by the EWSFLI1 fusion gene has a specific expression in transplanted Ewing's sarcoma in mice.