Abstract:

Objective To investigate the inhibitory effect of hCAP-18/LL-37 gene transfection on proliferation in Lewis cells,and to study the possible antitumor mechanism.Methods DNA of hCAP-18/LL-37 transient transfection mediated by Polyfect was employed.The experimental cells were classified into untransfected cells,pcDNA4/Myc-His transfected cells and pcDNA4/Myc-His- LL-37 transfected cells.The proliferating abilities of Lewis cells 48 and 72h after transfection were measured by MTT colorimetric assay.The apoptosis of transfected Lewis cells was detected by flow cytometry and  fluorescence microscope.The expressions of Bax and Bcl-2 in transfected Lewis cells were determined by cellular and immunohistochemical technique.Results The proliferating viability of Lewis cells transfected by the recombinant plasmid was significantly inhibited,the inhibitory  rate of growth  was 3.51% and 17.65% compared with pcDNA4/Myc-His transfected cells.The apoptotic rate were 7.4%,4.4%,5.2% in untransfected cells,pcDNA4/Myc-His cells and pcDNA4/Myc-His- LL-37 cells, respectivly, by FCM measurement.The protein expression of Bax in transfected Lewis cells was increased,and there was significant difference compared with control(P< 0.05).The protein expression of Bcl-2 in transfected Lewis cells was decreased,but there was no significant difference compared with control(P>0.05).
Conclusion hCAP-18/LL-37 gene transfection can induce apoptosis of Lewis cells by  up-regulation of Bax and  down-regulation of Bcl-2 and inhibit the proliferating ability of Lewis cells.

Key words: hCAP-18/LL-37;transient transfection;carcinoma,Lewis lung;apoptosis