Retroviral vector mediated IL6 gene therapy for human colon cancer cells.

Objective: To investigate the regulatory effect of IL6 exression on colon cancer cells. Methods: Human IL6 gene was successfuly reconstructed into retroviral vector pZIPIL6cDNA and transfected into package cells PA317,which were then selected by antibiotic G418Human colon cancer cells HT29 were infected with the prepared recombinant virus granules.IL6 gene were analyzed with Northern Blot at transcription level and the expression of protein were measured with ELISA and MTT method.Furthermore,the tumor repression function of the transfected cells were observed in vivo and in vitro through cells growth curve,plating efficiency and the inoculated tumors in nude mice. Results:High titer recombinant virus granules were prepared and stably expressive transfected cells HT29IL6 were constructed,the amount of the secreted protein was 11325 pg/ml and the activity was 150U/ml.Doubling time of the transfected cells was 25 days and log phase of growth was 47 days,plating efficiency and repression rate were 221%and 50%respectively.The tumor forming time in the inoculated nude mice was 135days and the final diameters of the tumor were among 65 to 85 mm,signifiantly lower than the nontransfected cells. Conclusion: Mediated by retroviral vector,IL6 gene can be stably expressed in the human colon cancer cells,and the expression clearly repress the proliferation of colon cancer cells in vitro and growth of the inocculated tumor in vivo.