The Wild Type P53 Inhibits Lung Cancer Cell Growth And Its Modified Dc To Induce Specific Anti-tumor Immune Response In Experimental Studies

Objects: We observed the suppressing action of \vt-p53 gene to cell line with mutant p53 gene, further researched the function of wt-p53 gene of suppressing cancer cell growth. Then we study whether dendritic cells that transfected by p53 wild-type plasmid pC53-SN3 and control plasmid pCMV-neo could induced the specific immunoresponse of lung cancer in vitro. Methods: Screened p53 mutant cell line with PCR, immunohistochemical and SSCP. The cell line was transfected with pC53-SN3 and control plasmid pCMV-neo. Screened cell expressing wt-p53 stable with culture containing G418. Investigated the influence of wt-p53 gene through cell growth curve and clone-forming experiment. Used rhIL-4 and GM-CSF combine to induce DC from the enriched blood of the 24-lung cancer. Transfected DC with p53 wild-type plasmid pC53-SN3 and control plasmid pCMV-neo with lipofectamine separately. Then co-culture with unpurified T cells in order to induce potent CTL. The cytolytic of specific CTL against Calu-6 cell line were measured by using LDH-releasing assay. Results: We found that Calu-6 cell line had a mutant of p53 gene, in which transferred to in site of 204 code, the cell line transfected by pC53-SN3 grow slowly significantly, but there was no significant difference between Calu-6 cell transfected by control plasmid pCMV-neo and primitive Calu-6 cell. The rate of clone -forming was 90.6%. These results suggested that wt-p53 gene supplements the function of mutant p53 gene of Calu-6 cell and suppress the growth of cancer cell by modulating the cell cycle negativly. The phenotype of cells demonstrated that CD83, CD la, the markers of mature DCs, increased apparently after transfected by plasmid pC53-SN3, CD14 decreased apparently, but CD40, CD86, HLA-DR-3-the specific phenotype of DC remain almost the same as before transfected. The results of mixture-lymphocyte culture test exhibited that DC we induced could present antigen and stimulated the proliferation of lymphocyte. The percentage of poliferation was about 20-30%. Compared with T-IL-2, the cytolytic activity of T-DC- pC53-SN3 against Calu-6 cell line showed a significant increase, but cytolytic activity of T-DC-pCMV-neo and T-IL-2 had no significant difference. The examination result of phenotype indicated that the CDS, CD69, CD45RO/CD8 of T-DC- pC53-SN3 increased significantly, but CD3, CD4, CD86, ect, were not significantly different from those of T-DC-pCMV-neo. Conclusions: The research indicated wt-p53 gene could suppress the growth of cancer cell and modulating the cell cycle negativly. This study showed that DC transfected by wild-type p53 gene could induce potent CTL to kill tumor cell efficiently. Wild-type p53 gene as a kind means of cancer immunity therapy has a bright future.