Objective: To construct vectors that express therapeutic genes specifically in hepatocellular carcinoma, the TREs (Tissue-specific transcriptional regulatory elements) of natural human alpha-fetoprotein (AFP) was reconstructed.
Methods: Using subcloning techniques, the -870 bp(-)-3.06 kb fragment of the natural human AFP TREs was deleted to construct an artificial AFP(e/p) TREs which contains the "core" promoter and the -3.06 kb(-)-5.1 kb fragment of natural human AFP TREs that contains enhancer activity.
Results: By using chloramphenicol acetyltransferase (CAT) assay, the artificial AFP(e/p) TREs showed an activity 1.8 fold as high as that of the natural AFP TREs in an AFP positive human hepatocarcinoma cell line HepG2, and it also remained to be tissue-specific since there was no activity was detected in an AFP negative human larynxcarcinoma cell line Hep2.
Conclusions: These results indicate that the artificial AFP(e/p) TREs we have constructed has higher activity than the natural AFP TREs and it also remains its hepatocarcinoma specificity. The reconstructed AFP(e/p) TREs is suitable for constructing of gene therapy vector with hepatocarcinoma expression specificity.