The Potential of the Human Osteopontin Promoter and Single-Nucleotide Polymorphisms for Targeted Cancer Gene Therapy

Title:The Potential of the Human Osteopontin Promoter and Single-Nucleotide Polymorphisms for Targeted Cancer Gene Therapy

Volume: 15 Issue: 1

Author(s): X.G. Chen and W.T. Godbey

Affiliation:

Keywords: Alternative splicing, expression-targeting, gene delivery, SNP, SPP1.

Abstract: Regulatory elements of the osteopontin (opn) gene are attractive candidates for expressiontargeted gene therapy because numerous malignant cancers are marked by opn overexpression. The maximum opn promoter (^Popn)-driven reporter intensity obtained for tested cancer cell lines was as strong (102.69%) as positive-control transfections. At the same time, ^Popn-driven reporter expression was reduced by ~90% in non-cancer cell lineages. Deletion analysis of the -922 bp region opn promoter did not confirm published reports of a repressor area within 922 bases upstream of the transcriptional start site. Further enhancements to targeting and expression were obtained through incorporation of single-nucleotide polymorphisms (SNPs) into the promoter sequence. It was found that the SNPs -443C, -155GG, -66T led to increased ^Popn-driven transfection in cancer cells (fold increase of 1.23 ~ 3.48), with a concomitant decrease in reporter expression in normal controls (fold change of 0.69). Further investigations to confirm a correlation between endogenous opn mRNA levels and ^Popn-driven reporter expression produced a surprising lack of correlation (R²=0.24). However, taking into account opn mRNA splicing variants showed a strong negative correlation between mRNA levels of the variant opn-a and ^P opn-driven transgene activity (R²=0.95). These data have implications on how future searches for expression-targeting promoters should be conducted.

Cite this article as:

Chen X.G. and Godbey W.T., The Potential of the Human Osteopontin Promoter and Single-Nucleotide Polymorphisms for Targeted Cancer Gene Therapy, Current Gene Therapy 2015; 15 (1) . https://dx.doi.org/10.2174/1566523214666141127094033