Development of artificial chimerical gene regulatory elements specific for cancer gene therapy.
To achieve satisfactory outcome by the expression of therapeutic genes, it is of great importance to obtain efficient and high level of gene expression as well as minimizing inappropriate gene expression in non-target cells. To accomplish this goal for cancer gene therapy, we have evaluated the potential of cancer specific gene expression of functional promoter/enhancer elements in six putative cancer-specific genes (Tcf1alpha, C-Ha-Ras, CyclinE, Cdc25A, HK II, and hTert) using a luciferase reporter assay. Most of the reporter constructs showed higher activity in HepG2 cells than in non-transformed or stem cells, and, in particular, the hTert (E) or Tcf1alpha (T) regulatory element showed significantly higher activity. We have also constructed a series of artificial chimerical regulatory elements by combinatorial linking of E promoter and T enhancer. A dramatic decrease of activity was observed as the copy number of concatenated T/E regulatory elements increased. In contrast, in chimerical constructs containing two or three copies of regulatory elements of T/E, cell type preferential expression profiles were changed. Thus, both pGL3-TE and -TEE showed higher activity specifically in MCF7 breast cancer cells, whereas pGL3-TET showed moderate activity in several cancer cell lines of different origins. Our results demonstrate that although the transcriptional activities of synthetic promoters are weak, some cancer-specific regulatory elements are useful in developing optimized and systemic cancer-specific regulatory regions with potential application in targeted cancer cell therapy.
Shin
June Ho
JH
Department of Life Science and Research Institute of Natural Sciences, College of Natural Sciences, Hanyang University, Seoul 133-791, Korea.
Yi
Jea Kyu
JK
Lee
Young Jin
YJ
Kim
Ae Li
AL
Park
Mi Ae
MA
Kim
Sung-Hyun
SH
Lee
Heuiran
H
Kim
Chul Geun
CG
D020816:Amino Acid Motifs; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D005809:Genes, Regulator; D017930:Genes, Reporter; D005813:Genes, Synthetic / Q000235:genetics; D015316:Genetic Therapy / Q000379:methods*; D006367:HeLa Cells; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D051821:Lymphoid Enhancer-Binding Factor 1; D009369:Neoplasms / Q000628:therapy*; D009857:Oncogenes / Q000235:genetics; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D019098:Telomerase / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection
D004268:DNA-Binding Proteins; C497573:LEF1 protein, human; D051821:Lymphoid Enhancer-Binding Factor 1; D014157:Transcription Factors; D008156:Luciferases; D019098:Telomerase