The Therapeutic Effect Of IL-24 On Tumor Growth Of Human Cervical Cancer In BALB/C Nude Mice

Objective:To investigate the growth inhibition,apoptosis promotion and its action mechanism of gene recombinant plasmid pDC316-hIL-24 on human cervical cancer C33A cells xenografted in nude mice model.Methods:1.15 nude mice were injected subcutaneous of the armpit with cervical cancer C33A cells,to establish xenograft of nude mice model. The nude mice were randomly divided into 3 groups, IL-24 gene recombinant plasmid group, empty plasmid group, and PBS group, were respectively injected into tumor with Lipofectamine 2000 to interfere,observe general state of health of nude mice. The tumor volume was measured before every injection every three days, comparison of tumor volume after the intervention, tumor growth curve was generated based on changes in xenograft tumor volume. The mice were sacrificed after five injections,and tumor tissues were removed and weighted by scales to calculate the tumor inhibition rate.2.Determination of IL-24 the mRNA level of expression in xenograft tumor by RT-PCR.3.The histopathological changes of the tumor tissues were observed in each group by HE staining and as well as immunohistochemistry was determined the levels of the Bax and Bcl-2 in each group.Results:1.The mice model with the xenografts was established successfully .To the end of the experiment, after transfection IL-24 in xenograft,it has been expressed successfully in tumor cells. Growth of transplanted tumor was significantly inhibited in the IL-24 recombinant plasmid group, transplanted tumor volume and weight obviously smaller compared with the empty plasmid group and the PBS group(P<0.05), when there was no significant difference between the two control groups (P>0.05). The average growth inhibitory rate was 36% in IL-24 recombinant plasmid group (P<0.05) and 6.8% in empty plasmid group(P>0.05).2.A specific DNA band which is 620bp was amplified by RT- PCR in the IL-24 gene recombinant plasmid group, but there was not any DNA band in the empty plasmid group and PBS group.3.Pathological observation shows in recombinant plasmid group cervical cancer cells have focal necrosis zone and there were necrosis cell and nuclear fragmentation could be found.4.Immunohistochemistry revealed that, recombinant plasmid group the expression of Bcl-2 was degraded compared with the two control groups(P <0.05), however Bax expression was enhanced than the latter two (P<0.05), when there was no significant difference between the latter two(P>0.05).Conclusion:1.Recombinant plasmid pDC316-hIL-24 has significantly inhibition function on human cervical cancer C33A cells nude mice model xenografts growth.2.Recombinant plasmid pDC316-hIL-24 promotes C33A cells apoptosis, and its mechanism may be related to the up-regulation of bax expression,but the down-regulation of bcl-2.3.It may be a novel theory basis and experiment for gene therapy approach for human cervical cancer.