Our study favors a biomarker usage of antibody response to tankyrases. Spontaneous CD8(+) T-cell responses to these enzymes are rare and further investigation is needed to evaluate tankyrases as potential targets for cancer immunotherapy.
Violation of proliferation control is a common feature of cancer cells. We put forward the hypothesis that promoters of genes involved in the control of cell proliferation should possess intrinsic cancer specific activity. We cloned promoter regions of CDC6, POLD1, CKS1B, MCM2, and PLK1 genes into pGL3 reporter vector and studied their ability to drive heterologous gene expression in transfected cancer cells of different origin and in normal human fibroblasts. Each promoter was cloned in short (335-800 bp) and long (up to 2.3 kb) variants to cover probable location of core and whole promoter regulatory elements. Cloned promoters were significantly more active in cancer cells than in normal fibroblasts that may indicate their cancer specificity. Both versions of CDC6 promoters were shown to be most active while the activities of others were close to that of BIRC5 gene (survivin) gene promoter. Long and short variants of each cloned promoter demonstrated very similar cancer specificity with the exception of PLK1-long promoter that was substantially more specific than its short variant and other promoters under study. The data indicate that most of the important cis-regulatory transcription elements responsible for intrinsic cancer specificity are located in short variants of the promoters under study. CDC6 short promoter may serve as a promising candidate for transcription targeted cancer gene therapy.
Gene therapy is a fast-developing field of molecular medicine. New, effective, and cancer-specific promoters are in high demand by researchers seeking to treat cancer through expression of therapeutic genes. Here, we created a combinatorial library of tumor-specific chimeric promoter modules for identifying new promoters with desired functions. The library was constructed by randomly combining promoter fragments from eight human genes involved in cell proliferation control. The pool of chimeric promoters was inserted into a lentiviral expression vector upstream of the CopGFP reporter gene, transduced into A431 cells, and enriched for active promoters by cell sorting. The enriched library contained a remarkably high proportion of active and tumor-specific promoters. This approach to generating combinatorial libraries of chimeric promoters may serve as a useful tool for selecting highly specific and effective promoters for cancer research and gene therapy.
Core promoters with adjacent regions of the human genes CDC6, POLD1, CKS1B,
MCM2, and PLK1 were cloned into a pGL3 vector in front of the Photinus pyrails
gene Luc in order to study the tumor specificity of the promoters. The cloned
promoters were compared in their ability to direct luciferase expression in
different human cancer cells and in normal fibroblasts. The cancer-specific
promoter BIRC5 and non-specific CMV immediately early gene promoter were used
for comparison. All cloned promoters were shown to be substantially more active
in cancer cells than in fibroblasts, while the PLK1 promoter was the most
cancer-specific and promising one. The specificity of the promoters to cancer
cells descended in the series PLK1, CKS1B, POLD1, MCM2, and CDC6. The
bidirectional activity of the cloned CKS1B promoter was demonstrated. It
apparently directs the expression of the SHC1 gene, which is located in a
“head-to-head” position to the CKS1B gene in the human genome. This feature
should be taken into account in future use of the CKS1B promoter. The cloned
promoters may be used in artificial genetic constructions for cancer gene
therapy.
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