Objective:To analyze the role of human mda-7/IL-24 gene on the proliferation of human non-small cell lung cancer cell line (H460). Methods:The mda-7/IL-24 cDNA was subcloned into expression vector pcDNA3 and transient transfected in human lung carcinoma cell H460. The overexpressed mda-7/IL-24 was identified by RT-PCR using SP6 primer and mda-7/IL-24 upstream primer. The role of human mda-7/IL-24 on the proliferation of H460 cells was analyzed with MTT after transfection of (pcDNA3)-mda-7/IL-24 for 72h. Results:The mda-7/IL-24 cDNA was subcloned into pcDNA3 successfully. RT-PCR study showed that mda-7/IL-24 could express in H460 cells at different ratio of DNA and lipofectamine (1 ?g ∶ 2?l-1?g ∶ 4?l). Compared with H460 cells and H460 cells transfected with (pcDNA3), pcDNA3-mda -7/IL-24 could inhibit the proliferation of H460 cells. The inhibition rate was (18.4%). Conclusion:The mda-7/IL-24 can inhibit the proliferation of human non-small-cell lung carcinoma cell H460.

Objective To prepare recombinant mda-7/IL-24 adenovirus to study its function on the proliferation of small cell lung cancer NCI-H446 cells. Methods According to the manufacturer's instructions of AdEasy vector system, mda-7/IL-24 cDNA was subcloned into the adenoviral shuttle vector pAdTrack-CMV. The efficient recombination of adenoviral backbone vector pAdEasy-1 and pAdTrack-CMV-mda-7/IL-24 was achieved in bacteria E. coli BJ 5183. The recombinant adenoviral vector pAd-mda-7/IL-24 linearized by Pac Ⅰ was transfected into HEK293 cells with lipofectamine 2000. To generate higher titer viral stocks, the amplification of recombinant adenovirus was accomplished in packing cells. Viral titers were measured by tissue culture infectious dose 50 (TCID_ 50 ) method. Ad.mda-7/IL-24 was identified by PCR. The expression of pAd-mda-7/IL-24 in NCI-H446 cells was detected by Western-blot analysis. The function of Ad.mda-7/IL-24 on the proliferation of NCI-H446 cells was assayed by MTT after cells were infected by 50 pfu/ml adenovirus. Results The recombinant adenoviral shutter vector pAdTrack-CMV-mda-7/IL-24 and recombinant adenoviral vector pAd-mda-7/IL-24 were constructed successfully as identified by sequence analysis. PCR assay showed that adenovirus Ad.mda-7/IL-24 contained mda-7/IL-24 cDNA. After amplification in packing cell HEK293, the titer of virus was 2?10~ 10 pfu/ml measured by TCID_ 50 assay. Western-blot results identified that MDA-7/IL-24 could be expressed in NCI-H446 cells. After infected by 50 pfu/ml adenovirus, the proliferation of NCI-H446 cells was inhibited by 21.37% with MTT method. Conclusion Ad.mda-7/IL-24 can inhibit the growth of NCI-H446 cell obviously. This result lays foundation to study its function mechanism and to apply it in gene therapy of the small cell lung cancer.

Interleukin 24 ( IL-24) has a good prospect in tumor therapy because it can specifically inhibit proliferation in a variety of tumor cells in vitro and in vivo and induce apoptosis of tumor cells without affecting normal cells .Gene therapies which use recombinant adenovirus as a vector have some limitations that restrict the clinical application of IL-24. In comparison, protein drugs have tremendous advantages .In this paper, the progress in research on IL-24 gene engineering protein is elaborated .